REVIEW | doi:10.20944/preprints202111.0490.v1
Subject: Medicine & Pharmacology, Dentistry Keywords: CAD/CAM; dental ceramics; dental technology; digital dentistry; dental education; dental innovation; disruptive technology
Online: 25 November 2021 (20:06:23 CET)
Digital dentistry, including CAD/CAM dentistry, is perhaps the most disruptive innovation in dentistry to date. The rapid development of digital dentistry technologies over the past several decades has enabled clinicians to improve patient care by significantly reducing the time necessary for the restorative phase of treatment. Advancements in intra-oral scanning and computer-aided design and manufacturing (CAD/CAM), in conjunction with new dental CAD/CAM ceramic materials, have simplified patient care and made same-day dentistry a reality. This review aims to present the most recent advancements described in current literature as well as to document the successful implementation of digital dentistry into a predoctoral program. The overall process of CAD/CAM same-day dentistry and the accompanying advancements in software and materials were presented and discussed. Implementation of technology and personnel requirements were reviewed. CAD/CAM dentistry has been influential in shaping and improving dental practice and education, and this influence will only continue with time.
ARTICLE | doi:10.20944/preprints202001.0064.v1
Subject: Medicine & Pharmacology, Dentistry Keywords: dental enamel; dental caries; genomics; odontogenesis
Online: 8 January 2020 (06:35:12 CET)
Objectives: The hierarchical structure of enamel gives insight on the properties of enamel and can influence its strength and ultimately caries experience. Presently, past caries experience is quantified using the decayed, missing, filled teeth/decayed, missing, filled surface (DMFT/DMFS for permanent teeth; dmft/dmfs for primary teeth) or international caries detection and assessment system (ICDAS) scores. By analyzing the structure of enamel, a new measurement can be utilized clinically to predict susceptibility to future caries experience based on a patient’s individual’s biomarkers. The purpose of this study was to test the hypothesis that number of prisms by square millimeter in enamel and average gap distance between prisms and interprismatic areas, influence caries experience through genetic variation of the genes involved in enamel formation. Materials and Methods: Scanning electron microscopy (SEM) images of enamel from primary teeth were used to measure number of prisms by square millimeter and interprismatic spaces, prism density and gap distances between prisms in the enamel samples. The measurements were tested to explore a genetic association with variants of selected genes and correlations with caries experience based on the individual’s DMFT+ dmft score and enamel microhardness at baseline, after an artificial lesion was created and after the artificial lesion was treated with fluoride. Results: Associations were found between variants of genes including ameloblastin, amelogenin, enamelin, tuftelin, tuftelin interactive protein 11, beta defensin 1, matrix metallopeptidase 20 and enamel structure variables measured. Significant correlations were found between caries experience and microhardness and enamel structure. Negative correlations were found between number of prisms by square millimeter and high caries experience (r value= -0.71), gap distance between prisms and the enamel microhardness after an artificial lesion was created (r value= -0.70), and gap distance between prisms and the enamel microhardness after an artificial lesion was created and then treated with fluoride (r value= -0.81). There was a positive correlation between number of prisms by square millimeter and prism density of the enamel (r value= 0.82). Conclusions: our data support that genetic variation may impact enamel formation, and therefore influence susceptibility to dental decay and future caries experience. Clinical Relevance: The evaluation of enamel structure that may impact caries experience allows for hypothesizing that the identification of individuals at higher risk for dental caries and implementation of personalized preventative treatments may one day become a reality.
ARTICLE | doi:10.20944/preprints201609.0041.v1
Subject: Medicine & Pharmacology, Other Keywords: dental anxiety; dental fear; anxiolytics; nitrous oxide
Online: 12 September 2016 (10:32:47 CEST)
Dental anxiety (DA) negatively affects patients’ oral and overall health. This study explored attitudes and clinical practices of licensed Ohio general dentists who treat patients with DA. Methods: An anonymous self-administered mail survey was sent to 500 general dentists licensed and practicing in Ohio. Responses to 21 pre-coded questions were analyzed. Frequencies were examined; cross-tabs, Chi-Square, and Fischer’s Exact Test were calculated for statements according to dentists’ gender. Alpha was set at p = 0.05. Results: Nearly all respondents treated anxious patients; males were more likely to find it challenging than females. Dentists were most familiar with distraction, although half found nitrous oxide to be an effective tool. Female dentists were more likely than males to be familiar with anxiolytics and find them effective. Conclusion: Overall, Ohio general dentists are most familiar with using distraction and nitrous oxide during appointments for anxious patients. Gender differences exist in attitudes towards anxiolytic use for patients with DA. Practice Implications: By identifying techniques that are comfortable for patient and practitioner, oral health disparities associated with DA may be reduced.
ARTICLE | doi:10.20944/preprints202206.0107.v1
Subject: Medicine & Pharmacology, Dentistry Keywords: Access to Dental Care; COVID-19; Dental Public Health
Online: 7 June 2022 (11:22:41 CEST)
Background: The COVID-19 pandemic has changed the way dentistry has been practiced world over , this study sought to assess the impact of the COVID-19 pandemic on the patterns of attendance for dental treatment in a large hospital in Kuwait compare them to data from the year prior to the pandemic Methods: A total of 176,690 appointment records of 34,250 patients presenting to the AlJahra specialist hospital, Kuwait for dental treatment from April 2019 to March 2021 were analyzed. Types of procedures and the departments to which they presented were analyzed and the patterns of attendance before and during the pandemic were compared; Results: While there was a significant reduction in the number of orthodontic, endodontic and periodontal procedures there was no impact on oral surgery, restorative procedures or pediatric dentistry; Conclusions: There has been a return in the numbers of patients availing dental treatment, however, there has been a definite shift in the use of certain dental procedures .
COMMUNICATION | doi:10.20944/preprints202106.0407.v1
Subject: Medicine & Pharmacology, Dentistry Keywords: Dental Implants; biomechanical phenomena; dental prosthesis; finite element analysis.
Online: 15 June 2021 (14:20:23 CEST)
The effect of the different dental implants positioning region on the stress performance of the implant-supported prosthesis is not yet clear. This study evaluated the dental treatment with six dental implants in three different models and three different occlusal loading conditions, in terms of the biomechanical response of implants, prosthetic screw and maxilla, using three-dimensional finite element analysis. The finite element models were modelled containing external hexagon implants, as well as a Cobalt-Chromium superstructure. Three types of loads were applied: in the area of the central incisors, first premolar and in the second molars. For the finite element simulations, the von-Mises stress peaks in the implant and in the surrounding cortical bone were analyzed. All recorded results reported higher values for the implant-supported prosthesis in group C compared to the groups A and B. The highest stress values, regardless the evaluated model, was in the prosthesis in group C and in screws, the smallest were in group A.
BRIEF REPORT | doi:10.20944/preprints202007.0734.v1
Subject: Medicine & Pharmacology, Dentistry Keywords: cannabinoid; CBD; dental care; dental plaque; tooth polish; polishing powder
Online: 31 July 2020 (06:02:24 CEST)
Introduction: Dental health problems including dental plaque are common health problems affecting people of different age groups globally. Air-polishing is a safe tooth polishing technique used by dental professionals for stain and plaque removal and as preventive procedure for dental health. Here we report the technical improvisation of existing air-polishing technique by supplementing cannabinoid powder into the classic polishing powder for effective removal of supragingival and subgingival plaque and inhibition of plaque forming bacteria. Methods: The cannabidiol (CBD) powder was added to the tooth polishing powder (AIR-N-GO, classic) at 1% (wt/wt) ratio. The study was conducted on 12 patients, of which 6 received regular polishing treatment and 6 received CBD-supplemented polishing treatment. The dental plaque samples were collected before and after each treatment and subjected to in vitro microbiological analysis and the colony forming units (CFU) were analyzed using automated colony counter. Results: Based on in vitro microbiological analysis, the average CFU of interdental space samples collected from post-CBD-supplemented polishing treatment was significantly reduced (linear fold change between 3.9-18.4) compared to that of post-regular polishing (linear fold change between 1.0-2.6) treatment. Conclusions: CBD-supplemented polishing powder can help in effective removal and killing of dental plaque bacteria during the polishing treatment. CBD powder can be added as enhancing supplement to the existing polishing powders.
Subject: Physical Sciences, Acoustics Keywords: oral health; dental checkup; Korea National Health and Nutrition Examination Survey (KNHANES); dental care; dental service utilization
Online: 15 March 2021 (10:57:43 CET)
To identify gender- and age-related associations between adult dental checkups and unmet dental care needs, we analyzed data of 14,000 participants, ages ≥ 19, from the 7th Korea National Health and Nutrition Examination Survey (2016–2018) (KNHANES VII). Data was collected via self-report questionnaires and interviews. Complex sample chi-square test and multiple logistic regression analysis indicated 31.7% of participants had unmet dental care needs; in the prior 12months, 67.1% had not utilized dental services, and 43.3% had not received dental checkups. Odds ratios (ORs) for dental checkups and unmet dental needs were 8.87 (CI:7.80–10.09, p < 0.001) for those who used dental services and 1.28 (CI: 1.13–1.44, p < 0.001) for those who had not. Significant age-dependent associations between those not receiving dental checkups and the rate of unmet dental care include men and women aged 50–59 years (OR: 1.77; CI = 1.22–2.58 and OR: 1.43; CI: 1.02–2.02; p = 0.040, respectively) and women ≥ 70 years (OR = 1.79, CI = 1.20–2.66, p = 0.004). Reducing unmet dental care needs requires greater public health promotion and education regarding regular dental checkups; additional practical strategies could enhance dental checkup compliance.
REVIEW | doi:10.20944/preprints202105.0296.v1
Subject: Life Sciences, Biochemistry Keywords: CAD/CAM; dental restoration; ceramic; all-ceramic; survival; fixed dental prosthesis
Online: 13 May 2021 (13:18:51 CEST)
Although CAD/CAM ceramics present a promising alternative to metal-ceramic fixed dental prostheses, little is known about their mid- and long-term clinical performance. This systematic review aims to estimate the survival and success rates and describes the underlying complication characteristics for CAD/CAM tooth-supported fixed dental prostheses (FDPs). We systematically searched MEDLINE and Web of Science to find relevant prospective studies with a follow-up of at least one year. We estimated pooled 1-, 5- and 10-year survival and success rates by combining the collected data in a Poisson regression model. Descriptive statistics were conducted to evaluate the distribution of failures and complications in the included studies. Risk of bias for the included studies was assessed with an adapted checklist for single-arm trials. Pooled estimated 1-, 5-, and 10-year survival rates ranged from 93.80% to 94.66%, 89.67% to 91.1%, and 79.33% to 82.20%, respectively. The corresponding success rates, excluding failures but including any other types of intervention, were 94.53% to 96.77%, 90.89% to 94.62%, and 81.78% to 89.25%. Secondary caries was the most frequent cause of failure, followed by chipping of the veneering. The most common cause of complication, excluding failures but requiring intervention, was chipping of the veneering. Risk of bias was generally acceptable for the included studies, with 7 studies associated with low risk of bias, 8 studies with a moderate risk of bias, and 3 studies with serious risk of bias. The current meta-analysis on CAD/CAM supported FDPs revealed satisfying survival and success rates for up to 10 years of exposure. More prospective studies focusing on long-term performance are needed to strengthen the evidence currently available in the literature.
ARTICLE | doi:10.20944/preprints202206.0239.v1
Online: 16 June 2022 (10:54:10 CEST)
Objective: The purpose of the present study was to analyze the management of dental extractions in patients affected by coagulation disorders in order to prevent bleeding intraoperative and postoperative complications. Subjects and Methods: This study included 17 patients with a diagnosis of a coagulation disorder, who had been subjected to a single or multiple dental extraction. Recombinant activated Factor VII was administered in those patients who were affected by a deficit of factor VII ranged between 10,5% and 21%. The other patients were treated locally with tranexamic acid. Results: A total of 50 teeth were extracted, 7 by surgical extraction and 43 by simple extraction. Of the 17 patients included 9 of them suffering from factor VII deficiency, 5 from factor V deficiency, 1 from Glanzmann's thrombasthenia and 2 from Haemophilia A. Pretreatment with recombinant activated factor VII was performed on a total of 8 patients with factor VII deficiency; the remaining 9 patients underwent tranexamic acid treatment. 1 hemorragic postoperative complication was observed. Conclusions: Surgical and no surgical extractions appear to be a safe procedure for patients affected by coagulation disorders when appropriate prophylaxis is adopted.
REVIEW | doi:10.20944/preprints202006.0102.v1
Subject: Medicine & Pharmacology, Dentistry Keywords: COVID-19; COVID pandemic; COVID and dental practise; dental public health; infection control
Online: 7 June 2020 (15:44:33 CEST)
Background: SARS-CoV-2 has resulted in a global pandemic, COVID-19. The disease has spread outrageously from Wuhan, china to rest of the world affecting millions of people. The human transmission is mainly known to occur by aerosols. As almost every dental procedure is associated with aerosol production, oral health care professionals are at a high risk of getting the infection. An attempt has been made to render cohesive practical suggestions for dental professionals amid COVID-19 outbreak. Objectives: The paper aims at providing evidence based information in managing dental patients during this pandemic. Material and Methods: The paper provides a broad overview of predominant findings based on electronic database search regarding COVID-19 outbreak and its effect on dental practice. Conclusion: Dental care should not be neglected due to the pandemic. Thorough knowledge about the disease and its prevention will not only help us in providing care to these patients but will also help in preventing the nosocomial spread of infection.
REVIEW | doi:10.20944/preprints202101.0306.v2
Subject: Medicine & Pharmacology, Allergology Keywords: Anemia; dental; management; oral manifestations
Online: 17 February 2021 (10:45:35 CET)
Anemia is a condition of decreased red blood cell number or hemoglobin concentration, or of disturbance in their function, ultimately leading to decreased oxygen transport to tissues. Many factors and diseases may lead to anemia, with wide manifestations systemically as well as orally. Therefore, a sound understanding of this condition is essential for the dental practitioner, with emphasis on alerting signs, dental management and proper communication with patient’s physician.
ARTICLE | doi:10.20944/preprints201905.0117.v1
Online: 10 May 2019 (10:30:14 CEST)
Dental scaling has high importance in oral health due to its effect on preventing the teeth root destruction. Moreover, it can influence other health aspects such as reducing the risk factor of infective endocarditis. There are various devices applicable to dental scaling. It is essential to select the most appropriate type of instrument to achieve more efficient scaling. Multi-Attribute Decision Making (MADM) is a mathematical approach widely applied in for selecting the best alternative based on essential criteria. In the present research, several criteria including cost, ease of use and sterilization, durability and effectiveness considered as criteria for device selection. The experts in the related field were asked to score the criteria and corresponded alternative. According to the results, obtained by applying the TOPSIS method, Piezon Master is the most option which is mainly due to its durability and effectiveness. The second rank belongs to Cavitron due to its ease of use and sterilization in addition to affordable cost.
Subject: Medicine & Pharmacology, Dentistry Keywords: odontogenic infection; dental abscess; head and neck infection; dental epidemiology; racial discrepancy; gender discrepancy
Online: 2 November 2020 (10:33:47 CET)
Odontogenic infections are infections of the orofacial structures arising from dental disease. Despite its preventability, it exerts a significant burden on healthcare infrastructure worldwide. Our study explored the various different microbiological, social, and epidemiological characteristics of 103 cases of odontogenic infections at our regional center which demonstrated specific predilections for the young and middle-aged, those with diabetes mellitus, African American/Black and Hispanic ethnicities, posterior teeth, left-sided dentition, and male gender. However, nuances and exceptions to these trends were also seen with specific groups that may complicate treatment.
ARTICLE | doi:10.20944/preprints202104.0791.v1
Subject: Medicine & Pharmacology, Other Keywords: COVID-19 Vaccines; Cross-Sectional Studies; Decision Making; Dental Education; Dental Students; International Association of Dental Students; Mass Vaccination; Multicenter Study; Social Determinants of Health
Online: 30 April 2021 (15:26:07 CEST)
Background: Acceleration of mass vaccination strategies is the only pathway to overcome the COVID-19 pandemic. Healthcare professionals and students have a key role in shaping public opinion about vaccines. This study aimed to evaluate the attitudes of dental students globally towards COVID-19 vaccines and explore the potential drivers for students' acceptance levels; Methods: A global cross-sectional study was carried out in February 2021 using an online ques-tionnaire. The study was liaised by the scientific committee of the International Association of Dental Students (IADS), and data was collected through the national and local coordinators of IADS member organizations. The dependent variable was the willingness to take the COVID-19 vaccine, and the independent variables included demographic characteristics, COVID-19-related experi-ence, and the drivers of COVID-19 vaccine-related attitude suggested by the WHO-SAGE; Results: A total of 6639 students from 22 countries representing all world regions responded to the ques-tionnaire properly. Their mean age was 22.06 ± 2.79 (17-40) years, and the majority were females (70.5%), in clinical years (66.8%), and from upper-middle-income economies (45.7%). In general, 22.5% of dental students worldwide were hesitant, and 13.9% rejected COVID-19 vaccines. The students in low- and lower-middle-income (LLMI) economies had significantly higher levels of vaccine hesitancy compared to their peers in upper-middle- and high-income (UMHI) economies (30.4% vs 19.8%; p < 0.001); Conclusions: The global acceptance level of dental students for COVID-19 vaccines was suboptimal, and their worrisome level of vaccine hesitancy was influenced by the socioeconomic context where the dental students live and study. The media and social media, public figures, insufficient knowledge about vaccines, and mistrust of governments and the pharmaceutical industry were barriers to vaccination. The findings of this study call for further implementation of epidemiology (infectious diseases) education within undergraduate dental curricula.
ARTICLE | doi:10.20944/preprints202202.0354.v1
Subject: Mathematics & Computer Science, Artificial Intelligence & Robotics Keywords: Dental segmentation; deep learning; panoramic radiograph
Online: 28 February 2022 (10:15:46 CET)
Introduction: Dental segmentation in panoramic radiograph has become very relevant in dentistry, since it allows health professionals to carry out their assessments more clearly and helps them to define the best possible treatment plan for their patients. Objectives: In this work, a comparative study is carried out with four segmentation algorithms (U-Net, DCU-Net, DoubleU-Net and Nano-Net) that are prominent in the medical literature on segmentation and we evaluate their results with the current state of the art of dental segmentation in panoramic radiograph. Methods: These algorithms were tested with a dataset consisting of 1,500 images, considering experiment scenarios with and without augmentation data. Results: DoubleU-Net was the model that presented the best results among the analyzed models, reaching 96.591% accuracy and 92.886% Dice using the dataset with data augmentation. Another model that stood out was Nano-Net using the dataset without data augmentation; this model achieved results close to that of the literature with only 235 thousand trainable parameters, while the literature model (TSASNet) contains 78 million. Conclusions: The results obtained in this work are satisfactory and present paths for a better and more effective dental segmentation process.
BRIEF REPORT | doi:10.20944/preprints202108.0462.v1
Subject: Medicine & Pharmacology, Dentistry Keywords: Dental Implants; fatigue; mechanical tests; torque
Online: 24 August 2021 (09:04:13 CEST)
The aim of this study was to compare the screw removal torque of mini conical prosthetic components and straight trunnion of indexed morse taper implants, after mechanical cycling. The sample consisted of 40 implants and 20 mini-conical prosthetic components (MC group) and 20 straight trunnion components (ST group). Each group consisted of 10 specimens, with 2 implants in each, and cobalt-chromium metallic crowns were screwed into each sample. The components of the MC group received a torque of 20 N.cm with a digital torque wrench and after 10 minutes were retightened with the same value as the initial torque. The components of the ST group received a torque of 30 N.cm, with a digital torque wrench and after 10 minutes, they were retightened with the same value. The screws of the respective crowns of the two groups received a torque of 10 N.cm and after 10 minutes were retightened with the same value. Each group was subjected to the fatigue test in a mechanical cycler at 2.000.000 cycles, with a load of 250 N and frequency of 4 Hz. At the end of the fatigue test, the loosening torque of each screw of the specimens was measured through a digital torque wrench. The data were analyzed by two-way ANOVA and Tukey test. In both groups, there were loss of torque. The results showed no statistic difference between MC and ST groups.
ARTICLE | doi:10.20944/preprints202012.0371.v1
Online: 15 December 2020 (10:35:17 CET)
Abstract: The study aimed to determine the factors associated with the avoidance of dental preventive care in adolescents and their parents in the framework of The Youth and Parents Risk Factor Behavior Survey in Slovakia has been initiated during the years 2015/2016. The data were collected using two separate standardized questionnaires: (i) the questionnaire for adolescents (n=515) and (ii) the questionnaire for parents (n=681). The study group consisted of 57 adolescents (54.4% males) who did not visit the dentist for preventive care in the previous year. The control group consisted of 458 adolescents (35.8% males) who visited a dentist for preventive care at least once in the previous year. A significantly higher number of males (54.4%), older adolescents (21.4%) were not visiting dental preventive care regularly. Incomplete family (56.1%), stressful situations at home (17.5%), and feeling unwell were observed as the factors contributing to the avoidance of dental preventive care. More than 34.5% of adolescents were not visiting either dental preventive care but also pediatric preventive care (AOR=5.14; 95%CI=2.40, 10.99). Divorced mothers and mothers with household income lower than 900 € had significantly higher dental care avoidance in their children. A significantly higher percentage of fathers from the exposed group were not visiting dental preventive care regularly (47.8%; p< .05). The results of the study can be used as an educational intervention steps focusing on the influence of parental and adolescent behavior in dental preventive care.
BRIEF REPORT | doi:10.20944/preprints202110.0285.v1
Subject: Medicine & Pharmacology, Dentistry Keywords: dental materials; finite element analysis; prosthodontics; biomechanics
Online: 20 October 2021 (10:00:45 CEST)
Evidence regarding the effect of the onlay preparation design for different CAD/CAM restorative materials considering the preservation of cusps is lacking. Molars were 3D modeled in four preparation designs for onlay restoration: traditional design with functional cusp coverage (TFC), non-retentive design with functional cusp coverage (NFC), traditional design with non-functional cusp coverage (TNFC), non-retentive design with non-functional cusp coverage (NNFC). Restorations were simulated with two CAD/CAM restorative materials: LD – lithium disilicate (IPS e.max CAD) and RC - resin composite (GrandioBloc). A 100 N axial load was applied to the occlusal surface simulating the centric contact point. Von Mises (VM) and maximum principal (Pmax) stresses were evaluated for restorations, cement layer and dental substrate. The non-retentive preparation design reduced the stress concentration in the tooth structure in comparison to the conventional retentive design. For LD onlays, the stress distribution on the restoration intaglio surface showed that the preparation design as well as the prepared cusp, influenced the stress magnitude. The non-retentive preparation design provided better load distribution in both restorative materials and more advantageous for tooth structure. The resin composite restoration on non-functional cusp is recommended when functional cusp is preserved, in order to associate conservative dentistry and low stress magnitude.
ARTICLE | doi:10.20944/preprints202105.0363.v1
Subject: Materials Science, Biomaterials Keywords: Dental composite, Methacrylated calcium phosphate, translucency, Biomineralization
Online: 16 May 2021 (22:39:21 CEST)
The aim of this study was to synthesize and characterize a novel Methacrylate- functionalized Calcium Phosphate (MCP) used as a bioactive compound for innovative dental composites. The characterization was accomplished by Attenuated Total Reflectance Fourier-Transform Infrared Spectroscopy (ATR-FTIR), X-Ray Diffraction Analysis (XRDA), Scanning Electron Microscopy (SEM), and EnergyDispersive Spectroscopy (EDS). The incorporation of MCP as a bioactive filler in esthetic dental composite formulations and the ability of MCP containing dental composites to promote precipitation of hydroxyapatite (HAp) on the surfaces of those dental composites was explored. The translucency parameter, depth of cure, degree of conversion, ion release profile, and other physical properties of composites were studied with respect to the amount of MCP added to the composites. Composites containing 3 Wt.%, 6 Wt.%, and 20 Wt.% MCP were evaluated at 7, 14, and 21 days. The progress of surface precipitation of hydroxyapatite on MCP-containing dental composites was studied by systematically increasing the MCP content in the composite and the time of specimen storage in Dulbecco’s phosphate-buffered solution with calcium and magnesium. It was found that there was a direct correlation between the percentage of MCP in a composite formulation, the amount of time the specimen was stored in PBS, and the deposition of hydroxyapatite on the composite’s surface
REVIEW | doi:10.20944/preprints202008.0075.v1
Subject: Materials Science, Biomaterials Keywords: dental materials, nanomaterials, zeolite, graphene, nanoparticles, nanofibers
Online: 4 August 2020 (04:48:03 CEST)
The results of the bibliographic analysis show that the most explored nanomaterials in dentistry are graphene and carbon nanotubes, and their derivatives. A detailed analysis and a comparative study on their applications show that, although they are quite similar, graphene based materials seem to be more promising for most of the applications of interest in dentistry. The bibliographic study also demonstrated the potential of zeolite based materials, although the low number of studies on their applications shows that they have not been totally explored, as well as other porous nanomaterials that found important applications in medicine, such as metal organic frameworks, have not been explored. Subsequently, it is expected that the research effort will concentrate in graphene and zeolite based materials in the incoming years. Thus, present review paper presents a detailed bibliographic study, with more than 200 references, in order to describe briefly the main achievements that have been described in dentistry using nanomaterials, compare and analyze them in a critical way, with the aim of predicting the future challenges.
ARTICLE | doi:10.20944/preprints202002.0010.v1
Subject: Materials Science, Biomaterials Keywords: autogenous demineralized dentin matrix; osseointegration; dental implants
Online: 3 February 2020 (04:45:18 CET)
Autogenous demineralized dentin matrix (ADDM), derived from human extracted tooth, is commonly used as a bone-graft substitute to reconstruct alveolar defects when placing dental implants. The purpose of this retrospective study is to examine efficacy of ADDM in terms of surgical complications and marginal bone resorption by analyzing the medical records and radiographs of patients who received ADDM graft from 2008 to 2011 in our institute. Occurrence of complications, marginal bone loss around implants were investigated with regard to the type of defect, location of bone grafting, and types of bone graft techniques. ADDM-based bone grafting was performed on 221 sites in 82 patients and 208 implants were placed afterwards: The percentage of complications after bone grafting was 15.84%, and the implant survival rate was 95.19%. All complications were resolved with conventional treatment except for the 10 cases of osseointegration failure. The average marginal bone loss was 0.31 mm at the last examination after the average follow-up period of 7.2 years. Within the limitation of this study, the results of long-term follow-up are consistent with the short-term results of relevant studies. ADDM can produce promising clinical outcomes when used for alveolar ridge augmentation around implants.
COMMUNICATION | doi:10.20944/preprints201806.0203.v1
Subject: Materials Science, Biomaterials Keywords: Zirconia; primer; priming; bonding; catechol; dental; prosthodontics
Online: 13 June 2018 (06:06:31 CEST)
Zirconia has recently become one of the most popular dental materials in prosthodontics being used in crowns, bridges, and to implants. However, weak bonding strength of dental adhesives and resins to zirconia surface has been a grand challenge in dentistry, thus finding a better adhesion to zirconia is urgently required. Marine sessile organisms such as mussels use a unique priming strategy to produce a strong bonding to wet mineral surfaces; one of the distinctive chemical features in the mussel’s adhesive primer proteins is high catechol contents among others. In this study, we pursued a bioinspired adhesion strategy, using a synthetic catechol primer applied to dental zirconia surfaces to study the effect of catecholic priming to shear bonding strength. Catechol priming provided a statistically significant enhancement (P < 0.05) in shear bonding strength compared to the bonding strength without priming, and relatively stronger bonding than commercially available zirconia priming techniques. This new bioinspired dental priming approach can be an excellent addition to the practitioner’s toolkit to improve dental bonding to zirconia.
REVIEW | doi:10.20944/preprints201802.0051.v1
Subject: Life Sciences, Biotechnology Keywords: metals; dental regeneration; bioactivity; tissue regeneration; bone
Online: 6 February 2018 (05:25:46 CET)
The regeneration of bone tissue is a main purpose of most therapies in dental medicine. For bone regeneration, calcium phosphate (CaP)-based substitute materials based on natural (allo- and xenografts) and synthetic origins (alloplastic materials) are applied for guiding the regeneration processes. The optimal bone substitute has to act as a substrate for bone ingrowth into a defect, while it should be resorbed even in the time frame needed for complete regeneration up to the condition of restitution ad integrum. In this context, the modes of action of CaP-based substitute materials have been frequently investigated and it has been shown that such materials strongly influence regenerative processes such as osteoblast growth or differentiation and also on osteoclastic resorption due to different physicochemical properties of the materials. However, the material characteristics needed for the required ratio between the formation of new bone tissue and material degradation has not been found until now. The addition of different substances such as collagen or growth factors and also of different cell types have already been tested but did not allow for sufficient or prompt application. Moreover, metals or metal ions are differently used as basis or as supplement for different materials in the field of bone regeneration. Moreover, it has already been shown that different metal ions are integral components of bone tissue playing functional roles in the physiological cellular environment as well as in the course of bone healing. The present review focuses on frequently used metals as integral parts of materials designated for bone regeneration with the aim to give an overview of currently existing knowledge about the effects of metals in the field of bone regeneration.
ARTICLE | doi:10.20944/preprints202108.0413.v3
Subject: Medicine & Pharmacology, Dentistry Keywords: Dental Age Measurement; Dental Radiography; Orthopantomogram; Convolutional Neural Network; K-Nearest Neighbour; Health Data Analytics; Biomedical Machine Learning
Online: 12 April 2022 (10:12:48 CEST)
Age estimation in dental radiographs Orthopantomography (OPG) is a medical imaging technique that physicians and pathologists utilise for disease identification and legal matters. For example, for estimating post-mortem interval, detecting child abuse, drug trafficking, and identifying an unknown body. Recent development in automated image processing models improved the age estimation's limited precision to an approximate range of +/- one year. While this estimation is often accepted as accurate measurement, age estimation should be as precise as possible in most serious matters, such as homicide. Current age estimation techniques are highly dependent on manual and time-consuming image processing. Age estimation is often a time-sensitive matter in which the image processing time is vital. Recent development in Machine learning-based data processing methods has decreased the imaging time processing; however, the accuracy of these techniques remains to be further improved. We proposed an ensemble method of image classifiers and transfer learning techniques to enhance the accuracy of age estimation using OPGs from one year to a couple of months (1-3-6). This hybrid model is based on convolutional neural networks (CNN) and K nearest neighbours (KNN). The hybrid (HCNN-KNN) model was used to investigate 1,922 panoramic dental radiographs of patients aged 15 to 23. These OPGs were obtained from the various teaching institutes and private dental clinics in Malaysia. To minimise the chance of overfitting in our model, we used the principal component analysis (PCA) algorithm and eliminated the features with high correlation. To further enhance the performance of our hybrid model, we performed systematic image pre-processing. We applied a series of classifications to train our model. We have successfully demonstrated that combining these innovative approaches has improved the classification and segmentation and thus the age-estimation outcome of the model. Our findings suggest that our innovative model, for the first time, to the best of our knowledge, successfully estimated the age in classified studies of one year old, six months, three months and one-month-old cases with accuracies of 99.98, 99.96, 99.87, and 98.78 respectively.
ARTICLE | doi:10.20944/preprints202111.0147.v1
Online: 8 November 2021 (13:40:53 CET)
IntroductionDiversity is known to be important but diversity of staff working in dental schools in the UK and Ireland is low in comparison with the dental profession and the overall population. AimsTo provide a detailed snapshot of the diversity of dental academic staff in 2021 including staff working in academic and clinical roles.MethodsAn online survey was circulated to dental schools by Dental Schools Council. Questions included dates of graduation and key career milestones, demographics and indicators of esteem. Free text questions were also included.ResultsThere was a high degree of variability in dental academic careers which made direct comparisons difficult. Neither gender nor race appeared to be associated with a faster career progression. Females and those of racialised minority were less represented at the most senior grades. For those who had completed specialty training, racialised minority staff were far less likely to be working at consultant grade than their White equivalents.ConclusionThere are differences in career progression between staff in dental schools. The high amount of individual variability makes these difficult to quantify except at the most senior positions. Qualitative information is needed to contextualise the results and provide additional information.
Subject: Behavioral Sciences, Applied Psychology Keywords: teeth; greyhound; intervention; brushing; calculus; gingivitis; dental; periodontal
Online: 19 May 2021 (07:53:28 CEST)
Periodontal disease is one of the most common conditions affecting dogs worldwide and is reported to be particularly prevalent in racing greyhounds. A range of potential risk factors have been hypothesised. Previous research has suggested, regular tooth brushing can reduce both calculus and gingivitis, but the frequency required is unclear. Here, we report a controlled blinded in-situ in which kennel staff brushed 160 racing greyhounds’ teeth (living at six kennel establishments), either weekly, daily or never over two-month period. All visible teeth were scored for calculus and gingivitis, using previously validated scales. We calculated average scores for each of three teeth groups and overall averaging the teeth groups. Changes were compared to baseline. After two months, the total calculus scores (controlling for baseline) were significantly different in the three treatemnet groups, (F(2,129) = 10.76, p<0.001) with both weekly and daily brushing resulting in significant reductions. Gingivitis was also significantly different (F(2,128) = 4.57, p=0.012), but in this case, only daily brushing resulted in a significant reduction. Although dogs in different kennels varied significantly in their levels of both calculus (F(5,129) =8.64, p<0.001), and gingivitis (F(5,128)=3.51 p=0.005), the intervention was generally similarly effective in all establishments. Teeth groups varied and incisors were not significantly affected by treatment. Since trainers implementing the routine, reported minimal time commitment and positive experiences, we suggest that daily brushing is recommended for racing greyhounds, and that demonstrations should include attention to all teeth groups including incisors. Similar trials need to be conducted with retired greyhounds since these have been shown to present particularly high levels of periodontal disease.
ARTICLE | doi:10.20944/preprints202104.0093.v1
Subject: Medicine & Pharmacology, Allergology Keywords: International student; Depression; Bangladesh; Dental; CES-D; Undergraduate
Online: 5 April 2021 (10:34:16 CEST)
Background Bangladesh has been attracting international students on various subjects in recent times. Every year students from different parts of the world come to study undergraduate and postgraduate courses, mostly at private universities in Bangladesh. This study evaluates the depression status among international students who are studying dentistry in Bangladesh. Methods This cross-sectional survey was conducted among International undergraduate dental students who enrolled in the Bachelor of Dental Surgery program in nine public and private dental colleges in Bangladesh. A total of 206 students completed the survey, and CES-D 10 items Likert scale questionnaire was used for data collection. The Cronbach alpha for CES-D 10 scale items for this population is 0.812. Results The majority of the students (79.5%) are below 24 years of age, and students who cannot communicate well in Bengali (Bangla), about 60% of them have experienced depression. About 77.3% (p< 0.00) of the international students having financial difficulties exhibited depression. The international students who went through financial problems were two times more likely to suffer from depression (OR=2.38; p-value <0.01). Conclusion This study tried to highlight the struggles faced by international students in Bangladesh studying dentistry. It is evident from the findings that several factors influence students' mental well-being during demanding dental education years.
REVIEW | doi:10.20944/preprints202012.0455.v1
Subject: Medicine & Pharmacology, Allergology Keywords: Prognosis; prosthodontics; dental implant; clinical performance; risk factor.
Online: 18 December 2020 (11:34:49 CET)
Background: The treatment plan of prosthetic restorations supported by dental implants require comprehensive scientific knowledge to deliver prostheses with good prognosis, even before the implant insertion. This review aims to analyze the main prosthetic determinants of the prognosis of implant-supported prostheses. Methods: A systematic review of the literature was conducted with a PICO question: "For partially or complete edentulous subjects treated with implant-supported prostheses, which prosthetic factors could affect clinical outcomes?". A literature search was performed electronically in PubMed (MEDLINE), Scopus and Cochrane Library with the following equation [PROGNOS* OR RISK] FACTOR IMPLANT DENTAL, and by hand search in relevant journals and throughout the selected papers. Results: This revision was carried out based on 50 papers focused on several prosthodontics-related risk factors that were grouped as follows: implant-connection, loading protocol, transmucosal abutments, prosthetic fit, provisionalization, type of retention, impression technique, fabrication technique, and occlusion. More than a half of the studies were systematic reviews (30%), meta-analysis (16%) or prospective evaluations of prosthesis with various kinds of events (18%). But also narrative reviews of literature (14%) and in vitro/animal studies (16%) were found. Conclusions: The current literature provides insufficient evidence for most of the investigated topics. However, based on the accumulated data, it seems reasonable to defend that the best treatment approach is the use of morse taper implants with transmucosal abutments, recorded by means of rigidly splinted copings through the pick-up technique, and screwed by milled prosthesis occlusally adjusted to minimize functional overloading.
ARTICLE | doi:10.20944/preprints202011.0169.v1
Subject: Medicine & Pharmacology, Allergology Keywords: Dental treatment outcomes; Geographic Information Systems; Neighborhood contexts
Online: 3 November 2020 (15:33:02 CET)
ABSTRACT: Aims: This study aimed to explore the impacts of neighborhood-level socioeconomic contexts (e.g., income, education) on the therapeutic and preventative dental quality outcome of children aged 3 to 15 years. Materials and Methods Anonymized billing data of 842 patients reporting to a university Children’s Dental over three years met the inclusion criteria. Their access to care (OEV-CH-A), topical fluoride application (TFL-CH-A) and dental treatment burden (TRT-CH-A) were determined by dental quality alliance (DQA) criteria. The three oral health variables were aggregated at a neighborhood-level and analyzed with census data provided by Statistics Canada within a GIS framework. The forward sortation area (FSA) was chosen as a neighborhood spatial unit and regression models were run both the individual and neighborhood level. Results: The individual-level regression models showed significant negative associations between OEV-CH-A (p=0.027) and TFL-CH-A (p=0.001) and the cost of dental care. There was a significant negative association between TRT-CH-A and median household income. Neighborhood-level Ordinary Least Squares (OLS) linear regression models show negative associations of all three dental health variables (OEV-CH-A, TFL-CH-A, TRT-CH-A) with median household income and the number of households without a college degree. Conclusion: GIS and spatial quantitative approaches may be an effective tool to explore the impacts of socioeconomic variables on oral health outcomes.
REVIEW | doi:10.20944/preprints201911.0325.v1
Subject: Medicine & Pharmacology, Dentistry Keywords: dental caries; prevention; clinical trials; herbal; scoping review
Online: 27 November 2019 (03:57:04 CET)
It is currently recognized that an injudicious strategy in the last decades has been not only focusing of research typically on caries in children, but also the narrow focusing on fluoride, because despite sufficient availability of fluoride in water and oral healthcare products, caries levels escalate steadily as people get older and caries remain a main public health issue to be settled. In the last two decades the scientific community intensified efforts of exploring other products for caries prevention, herbal products being one of these approaches. Because preliminary evidence indicated that clinical trials for caries prevention with herbal products are heterogeneous in design, quality and products evaluated, we performed a scoping review intended to explore the main characteristics of such clinical trials. From an initial collection of 1986 unique papers from different literature databases, 56 articles satisfied the inclusion and exclusion criteria. The species investigated, dosage forms, study designs, duration of intervention, controls, endpoints, quality of reporting and risk of bias are discussed. 85.71% of the trials reviewed here reported positive results but given the methodological flaws and biases affecting them, it is difficult to conclude on the efficacy of those products based on the studies published thus far.
ARTICLE | doi:10.20944/preprints201904.0124.v1
Subject: Medicine & Pharmacology, Other Keywords: dental care; immigrants; inequalities; health survey; economic crisis
Online: 10 April 2019 (09:44:49 CEST)
This study evaluates inequalities in the use of dental services according to place of birth before and after the economic crisis in Spain. A cross-sectional study was performed in the population aged 18 to 65 years in Spain. We used data from three Spanish National Health Surveys for years 2006 (before the crisis), 2014 and 2017 (after the crisis). Log-binomial regression was used to quantify the association between region of origin and use of dental care services before and after controlling for the selected covariates. In 2006, we found a greater probability of not using dental care services in immigrants from Asia (PR:1.36, 95% CI:1.10–1.67) and Africa (PR:1.16; 95% CI:1.05–1.28) compared to the natives. For 2014, the probability of not using dental care services was greater for all immigrants compared to the natives, with the greatest odds for those from Africa (PR:1.71; 95% CI:1.46–2.01) and Asia (PR:1.3; 95% CI:1.23–1. 47). The associations for 2017 were weaker in magnitude than the ones observed for 2014, although stronger than for 2006. This study suggests that the economic recovery did not have the same impact for natives and immigrants regardless of regions of origin, given the observed inequalities in use of dental services.
ARTICLE | doi:10.20944/preprints202301.0363.v1
Subject: Medicine & Pharmacology, Dentistry Keywords: Periodontal Disease; Electronic Dental Record; Longitudinal Data; Data Quality; Dental Infor-matics; Clinical Course of Periodontal Disease; Periodontal Cohort Generation
Online: 19 January 2023 (13:01:27 CET)
Objective: Determine the feasibility of utilizing longitudinal electronic dental record (EDR) data to track change over time in patient periodontal disease (PD) and to generate three patient cohorts: 1) patients whose disease did not change over time, 2) patients whose PD progressed, and 3) patients whose disease improved over time using informatics approaches. Methods: We conducted a retrospective study of 28,908 patients who received a comprehensive oral evaluation between January 1, 2009, and December 31, 2014, at the Indiana University School of Dentistry (IUSD) clinics. We developed and tested three automated computer applications to: 1) diagnose periodontitis cases from periodontal charting, 2) retrieve clinician-documented diagnoses from clinical notes, and 3) track disease change over time. We also evaluated the density of longi-tudinal EDR data for the following follow-up times: 1) none, 2) up to 5 years, 3) >5 and <=10 years, and 4) >10 and <=15 years Results: Thirty-four percent (n=9,954) of the study cohort had up to five years of follow-up visits with an average of 2.78 visits with periodontal charting information. An average of three patient visits per year that contained periodontal charts (63,552) were utilized to obtain a diagnosis, which is considered excellent. For clinician-documented diagnoses from clinical notes, 42% of patients (n=5,562) had at least two PD diagnoses to determine their disease change. In this cohort with cli-nician-documented diagnoses, 72% percent of patients (n=3,919) did not have a disease status change between their first and last visits, 669 (13%) patients' disease status progressed, and 589 (11%) patients’ disease improved. Conclusions: This study demonstrated the feasibility of utilizing longitudinal EDR data to track disease changes over 15 years during the observation study period. We found excellent longitudinal data when diagnoses generated from periodontal charting were considered (three visits per pa-tient). This information can be now utilized for studying the clinical course of periodontitis.
ARTICLE | doi:10.20944/preprints202301.0301.v1
Subject: Medicine & Pharmacology, Dentistry Keywords: dental caries; caries experience; epidemiology, prevalence; risk; public health
Online: 17 January 2023 (08:56:34 CET)
Oral health surveys are essential to assess the dental caries experience and to influence national policies. This retrospective cross-sectional study aims to analysis dental caries experience who sought dental treatment in a reference university dental hospital at the Lisbon Metropolitan Area between January 2016 and March 2020. Full-mouth examination, sociodemographic, behaviors and medical information were included. Descriptive analyses and logistic regression analysis were applied to ascertain risk indicators associated with dental caries experience. A final sample of 9,349 participants (5,592 females/3,757 males) were included, aged 18 to 99 years old. In this population, caries experience was 91.1%, higher in female participants. Age (OR= 1.01, 95% CI [1.00-1.02], occupation (OR= 2.94, 95% CI [2.37-3.65], OR= 3.35, 95% CI [2.40-4.67], OR= 2.55, 95% CI [1.66-3.91], for employed, unemployed and retired, respectively), overweight (OR= 1.52, 95% CI [1.18-1.96]), reporting to never visited a dentist (OR= 0.38, 95% CI [0.23-0.64] and self-reported week teeth status (OR= 2.14, 95% CI [1.40-3.28]) were identified as risk indicators for the presence of dental caries, according to adjusted multivariable logistic analyses. These results highlight a substantial rate of dental experience in a Portuguese cohort and will pave the way for future tailored oral public health programs in Portugal.
ARTICLE | doi:10.20944/preprints202111.0455.v1
Subject: Medicine & Pharmacology, Dentistry Keywords: child anxiety disorders; screening; SCARED-C; psychometrics; dental practice
Online: 24 November 2021 (12:48:07 CET)
SCARED-C instrument (the child version, 41 items) is used for screening anxiety in children between 8 to 18 years old and has been first introduced by Birmaher & collab. in 1995, with good psychometric data - internal consistency from α =.74 to .93 - and good discriminative validity indices in the original versions (1997, 1999). Since then, many countries have adopted the scale, for its utility in identifying five subsets of anxiety disorders (subscales): somatic/panic disorder, generalized anxiety, separation anxiety, social phobia, and school avoidance. The present study contains the first Romanian translated and adapted version of the SCARED-C instrument on a community sample of 477 children (8-18 years old) from Mureș county schools. The instrument showed moderate to good internal consistency (α Cronbach from to .63 to .91 for the total scale) and good test-retest reliability (.70) on a subset of 85 children sample. A confirmatory factorial analysis (CFA) was conducted to test the factor structure of the Romanian version of SCARED-C; results showed that SCARED-C has good psychometric properties to be used for screening anxiety in Romanian children and adolescents. The implications for using SCARED-C in dental practice are discussed. Future studies need to be conducted for exploring convergent and discriminative validity of the instrument and the sensitivity to current DSM-V criteria. Application on a dental pediatric sample is also required.
ARTICLE | doi:10.20944/preprints202108.0244.v1
Subject: Medicine & Pharmacology, Dentistry Keywords: Phentolamine Mesylate; dental implants; haemodynamic changes; adverse effects; satisfaction
Online: 11 August 2021 (08:59:37 CEST)
The clinical application of Phentolamine Mesylate (PM) as an anaesthetic reversal agent has been documented in paediatric patients and in conservative dentistry, but no studies have been found in implant surgery. A prospective randomised study was conducted in 60 patients eligible for mandibular implant treatment, randomly divided between the Control Group (CG) and Experimental Group (EG), who were administered PM. Haemodynamic changes, adverse effects and patient satisfaction were assessed. No statistically significant differences in haemodynamic changes and postoperative pain were found between CG and EG (p<0.05), except for Systolic Blood Pressure (SBP) which increased slightly in EG, without posing a risk to the patient. There were no differences in the presence of adverse effects between the two groups, except in the CG which presented greater difficulty in chewing and biting (p<0.05) and the EG with greater pain in the injection area (p=0.043). 83.3% of the EG patients would request PM again for future dental treatment. The use of PM offers an alternative in implant surgery, without increasing the risks and increasing the patient's quality of life.
REVIEW | doi:10.20944/preprints202011.0196.v1
Subject: Materials Science, Biomaterials Keywords: Antimicrobial polymers; dental materials; cranio-maxilifacial regeneration; tissue engineering
Online: 4 November 2020 (12:47:55 CET)
Cranio-maxillofacial structure is a region of particular interest in the field of regenerative medicine due to both its anatomical complexity and the numerous abnormalities affecting this area. However, this anatomical complexity is what makes possible the coexistence of different microbial ecosystems in the oral cavity and the maxillofacial region, contributing to the increased risk of bacterial infections. In this regard, different materials have been used for their application in this field. These materials can be obtained from natural and renewable feedstocks or by synthetic routes with desired mechanical properties, biocompatibility and antimicrobial activity. Hence, in this review, we have focused on bio-based polymers, which by their own nature, by chemical modifications of their structure, or by their combination with other elements, provide a useful antibacterial activity as well as the suitable conditions for cranio-maxillofacial tissue regeneration. This approach has not been reviewed previously, and we have specifically arranged the content of this article according to the resulting material and its corresponding application, reviewing guided bone regeneration membranes; bone cements; and devices and scaffolds for both soft and hard maxillofacial tissue regeneration, including hybrid scaffolds, dental implants, hydrogels and composites.
ARTICLE | doi:10.20944/preprints202005.0104.v1
Subject: Medicine & Pharmacology, Dentistry Keywords: COVID-19; dental care; infection control; universal precautions; aerosol
Online: 7 May 2020 (05:21:20 CEST)
Dental services are significantly impacted by the COVID-19 pandemic. Almost all dental procedures carry a high infection risk for providers and patients due to spread of aerosols. As a consequence, national public health agencies, and dental professional associations have issued guidelines for enhanced infection control, personal protection equipment and limiting care to urgent or emergency services. However, there is no dental service concept for disaster preparedness or response that might be applied. Similarly, pathways to care provision in a post-pandemic future are missing. We propose Safe Aerosol-free, Emergent Dentistry (SAFE Dentistry) as one approach to dental services during and emerging from pandemics. The concept’s starting point is the identification of the most common patient needs. The next step is to replace common treatments relating to the most common needs with alternative interventions with less infection risk because they do not generate aerosols. SAFE Dentistry is innovative, safe, and responds to the requirements of a pandemic and post-pandemic emergence where the risk of disease transmission remains high. SAFE Dentistry thereby ensures continuity of dental services while protecting providers and patients from infectious pathogens. Moreover, SAFE Dentistry allows dental service providers to remain operational and generate income even under pandemic conditions. Implementation and policy options for SAFE Dentistry include universal availability without co-payments by patients and a uniform bundled payment scheme for providers to simplify budgeting, reimbursement and to provide easier administration during a pandemic. Adaptations and adjustments of the concept are possible and encouraged, as long as the principle of avoiding aerosol-generation is maintained.
ARTICLE | doi:10.20944/preprints201610.0102.v1
Subject: Life Sciences, Microbiology Keywords: dental caries; Streptococcus mutans; lactic acid bacteria; biofilm; glucosyltransferases
Online: 24 October 2016 (09:37:48 CEST)
Consumption of refined foods and beverages high in sugar make the teeth susceptible to the formation of biofilm, and lead to dental caries and diseases of the oral cavity such as periodontitis and periodontal disease. The aim of the present study was to determine the ability of selected probiotics to inhibit growth and biofilm formation by the cariogenic bacterium Streptococcus mutans in vitro. We screened strains of latic acid bacteria (LAB) (n=120) from the Bioresources Collection and Research Center (BCRC), saliva of healthy adults and infant stool. The antimicrobial activity of LAB in vitro was evaluated by agar spot culture and co-culture of the S. mutans strains. We determined the effect of heating and dilution factors (2- and 4-fold) on the antagonistic activity of LAB. Antagonistic substances in the spent culture suspensions (SCS) of LAB were precipitated by extraction with ammonium sulphate and chloroform to characterise the protein and lipophilic fractions. Results of co-culturing show that the SCS of the three LAB strains (Lactobacillus pentosus 13-1, 13-4 and Lactobacillus crispatus BCRC 14618) subjected to heat treatment showed significantly high antimicrobial activity. We found that substances produced by L. pentosus 13-4 which have the potential to exhibit antimicrobial properties might be lipophilic proteins. Additionally, we infer that the mechanism of reducing biofilm formation by Lactobacillus strains is associated with sucrose-dependent cell–cell adhesion and the gtfC level of glucosyltransferases (Gtfs) in the biofilm. Native LAB strains screened in our study may be used in chewing gums and other processed foods for preventing tooth decay.
ARTICLE | doi:10.20944/preprints202112.0083.v1
Subject: Medicine & Pharmacology, Psychiatry & Mental Health Studies Keywords: Psychological distress; Fear; Coping; COVID-19; Bangladesh; Dental; Mental health
Online: 6 December 2021 (15:22:59 CET)
Background: Psychological sufferings are observed among dental students during their academic years, which had been intensified during the COVID-19 pandemic. Objectives: This study assessed the levels and identified factors associated with psychological distress, fear and coping experienced by dental undergraduate students in Bangladesh. Methods: A cross sectional online survey was conducted during October-November, 2021. The Kessler Psychological Distress Scale (K-10), Fear of COVID-19 Scale (FCV-19S) and Brief Resilient Coping Scale (BRCS) were used in order to assess psychological distress, fear and coping strategies respectively. Results: A total of 327 students participated; the majority (72%) were 19-23 years old and females (75%). One in five participants were infected with COVID-19 and 15% reported contact with COVID-19 cases. Negative financial impact (AOR 3.72, 95%CIs 1.28-10.8), recent or past COVID-19 infection, contact with COVID-19 cases were associated with higher levels of psychological distress; but being a 3rd year student (0.14, 0.04-0.55) and being satisfied about current social life (0.11, 0.03-0.33) were associated with lower levels of psychological distress. Being a 3rd year (0.17, 0.08-0.39) and a 4th year student (0.29, 0.12-0.71) were associated with lower levels of fear. Health care service use and feeling positive about life were associated with medium to high resilience coping. Conclusions: This study iden-tified dental students in Bangladesh who were at higher risk of psychological distress, fear and coping during the ongoing pandemic. Development of mental health support system within dental institution should be considered in addition to the academic and clinical teaching.
ARTICLE | doi:10.20944/preprints202005.0493.v1
Subject: Mathematics & Computer Science, Artificial Intelligence & Robotics Keywords: Convolutional Neural Networks; Dental Diagnosis; Image Recognition; Diabetic Retinopathy detection
Online: 31 May 2020 (18:55:43 CEST)
Retinopathy is a human eye disease that causes changes in retinal blood vessels that leads to bleed, leak fluid and vision impairment. Symptoms of retinopathy are blurred vision, changes in color perception, red spots, and eye pain. In this paper, a new methodology based on Convolutional Neural Networks (CNN) is developed and proposed to diagnose and give a decision about the presence of retinopathy. The CNN model is trained by different images of eyes that have retinopathy and those which do not have retinopathy. The performance of the proposed model is compared with the related methods of DREAM, KNN, GD-CNN and SVM. Experimental results show that the proposed CNN performs better.
ARTICLE | doi:10.20944/preprints202004.0324.v1
Subject: Medicine & Pharmacology, Dentistry Keywords: hepatitis B; hepatitis C; occupational health; dental education; needlestick injury
Online: 19 April 2020 (04:37:08 CEST)
Introduction: Dental health care workers, particularly dental medicine students (DMS), are at an increased risk of hepatitis B virus (HBV) and hepatitis C virus (HCV) infection. The aim of our study was to assess the level of knowledge on HBV and HCV, estimate needlestick injury (NSI) prevalence and reporting practice in DMS at the University of Zagreb and analyze how enrolment in obligatory and supplemental courses affects knowledge and needlestick injury reporting practice. Materials and methods: The knowledge was assessed by our questionnaires based on Centers for Disease Control general handouts. Additional information was collected to examine the prevalence and reporting practice of NSI. Data was analyzed by descriptive statistical analysis, independent-samples t-tests, proportion analyses and combined factor analyses of categorical and quantitative variables in SPSS and R. Results: In total, 206 students participated. The overall level of HBV and HCV-related knowledge was poor with average scores being 61.90% and 51.35% respectively. Moreover, students enrolled in the first year demonstrated significantly lower levels of knowledge in comparison with their older peers. Of all participants 18.2% sustained a needlestick injury, and majority of them (78.95%) never reported the injury. Conclusion: In conclusion, DMS have low levels of knowledge on important occupational pathogens and poor NSI reporting practice. Moreover, formal education in the current form failed to significantly improve competence of students and theoretical knowledge translates poorly into more conscientious injury reporting practice. We should look for a better way to increase student awareness and level of knowledge on this topic.
REVIEW | doi:10.20944/preprints202003.0047.v1
Subject: Medicine & Pharmacology, Dentistry Keywords: socket shield; dental Implants; root membrane; buccal shield; aesthetic zone
Online: 4 March 2020 (04:45:00 CET)
There are different treatment options in modern dentistry for the replacement of lost dentition. Of these the most upcoming and acceptable treatment option is Dental implants. The common problem usually with immediate implant placement in the anterior region is the post-operative soft tissue contour as a part of the bone modelling during healing. Hurzeler et al in 2010 introduced a new technique called the “socket shield technique”. This technique has been used as an alternative treatment modality for immediate implant placement in the aesthetic zone.This review articles provides a detailed information regarding the clinical concept of Root membrane technique.
REVIEW | doi:10.20944/preprints201807.0443.v1
Subject: Medicine & Pharmacology, Dentistry Keywords: genetic factors; dental implants; bone quality; bone regeneration; success rate
Online: 24 July 2018 (06:01:10 CEST)
Dental implants provide a predictable treatment option for partial and complete edentulism via the placement of fixed permanent artificial root to support prosthetic dental crowns. Despite the high survival rates, long-term implant failures are still reported leading to implant removal and additional financial and health burdens. While extrinsic factors that improve survival rate of implants have been well explored, the impact of genetic factors on this matter is poorly understood. A systematic review and meta-analysis study was conducted to determine whether genetic factors contribute to increase the risk of dental implant failure. A comprehensive search for peer-reviewed articles on dental implants and genetics was performed using various literature database libraries. The study design was conducted according to PRISMA guidelines, and the obtained records were registered in PROSPERO database. According to the exclusion/inclusion criteria, 11 studies were eligible for this study out of 808 articles. The meta-analysis of the combined association studies of DNA variations and dental implants did not indicate an increase risk for implant failure due to DNA variations in IL-1B, IL-10 and TNF-α. This study emphasizes the need for larger randomized controlled clinical trails to inform clinicians and patients about the role of genetic factors on dental implant survival and success rate in healthy and compromised patients.
COMMUNICATION | doi:10.20944/preprints201806.0452.v1
Subject: Engineering, Industrial & Manufacturing Engineering Keywords: alignments, dental pulp stem cells, nanofiber, neurogenesis, reduced graphene oxide
Online: 27 June 2018 (15:53:18 CEST)
Stem cells derived from dental tissues—dental stem cells—are flavored due to their easy acquisition. Among them, dental pulp stem cells (DPSCs) extracted from the dental pulp have many advantages such as high proliferation and highly purified population. Although their ability for neurogenic differentiation has been highlighted and neurogenic differentiation using electrospun nanofibers (NFs) has been performed, graphene-incorporated NFs have never been applied for DPSC neurogenic differentiation. Here reduced graphene oxide (RGO)-polycaprolactone (PCL) hybrid electrospun NFs were developed and applied for enhanced neurogenesis of DPSCs. First, RGO-PCL NFs were fabricated by electrospinning with incorporation of RGO and alignments, and their chemical and morphological characteristics were evaluated. Furthermore, in vitro NF properties such as influence on the cellular alignments and cell viability of DPSCs were also analyzed. The influences of NFs on DPSCs neurogenesis was also analyzed. The results confirmed that an appropriate concentration of RGO promoted better DPSC neurogenesis. Furthermore, the use of random NFs facilitated contiguous junctions of differentiated cells, whereas the use of aligned NFs facilitated aligned junction of differentiated cells along the direction of NF alignments. Our findings showed that RGO-PCL NFs can be a useful tool for DPSC neurogenesis, which will help regeneration in neurodegenerative and neurodefective diseases.
ARTICLE | doi:10.20944/preprints201801.0037.v1
Subject: Materials Science, Biomaterials Keywords: Emdogain; amelogenin; dental pulp cells; cell differentiation; cell migration; mineralization
Online: 7 January 2018 (11:00:15 CET)
Enamel matrix derivative (EMD) is used for periodontal tissue regeneration therapy, and can induce mineralization in dental pulp cells (DPCs). We designed a synthetic peptide (SP) derived from the response of cells to EMD, and investigated the effect of the SP on potentiating osteogenesis in DPCs, which have a critical role of dental pulp homeostasis. DPCs were treated with 0, 10, 100, or 1000 ng/mL SP to determine its effect on cell proliferation, cell migration, cell differentiation, and mineralization. We then examined the molecular effects of the SP, focusing on changes in the mitogen-activated protein kinases (MAPK) signaling pathway in these cells. The SP significantly promoted DPC proliferation and migration. Cultures treated with the SP also showed an enhanced expression of markers of osteogenic differentiation and mineralization. The SP also induced the activation of MAPK signaling pathway components. These results suggest that our SP could promote the dental pulp tissue repair by hard tissue formation and the mineralization through activating MAPK signaling pathway. This study provides the first evidence that SP might be a new material for dental pulp tissue treatment.
ARTICLE | doi:10.20944/preprints202205.0348.v1
Subject: Materials Science, Biomaterials Keywords: zirconia; molecular precursor method; dental-implant; osseointegration; bone-to-implant contact
Online: 25 May 2022 (10:10:35 CEST)
In previous studies regarding the osseointegration of zirconia (ZrO2) implants, a lack of consistency was observed in the surface topographies of the ZrO2 and Ti samples because of the difficult processability of ZrO2 surfaces. To resolve this problem, we used the molecular precursor method (wet process), which is a surface-modifying technique that can easily change the surface chemistry without changing the surface topography. A roughened Ti surface was prepared using sandblasting (large-grit) and acid treatment. We were able to create ZrO2-coated Ti implants with the same topography as that of roughened Ti substrates using the molecular precursor method, which solution contained a Zr complex. The uniform presence of tetragonal Zr was confirmed, and the apparent zeta potential of the surface of the ZrO2-coated Ti implant was higher than that of Ti. In animal experiments, ZrO2-coated Ti implants showed an equivalent or higher bone-to-implant contact ratio compared to that of the non-coated implants inserted into the femur bone defects of the rats. ZrO2 with the same surface topography as that of roughened Ti exhibits a promotion of osteogenesis equivalent to or better than that of Ti in the early stages of bone formation.
ARTICLE | doi:10.20944/preprints202104.0045.v1
Subject: Life Sciences, Biochemistry Keywords: S. mutans; Phage therapy; Dental caries; S. mutans phage; Bacteriophage; Biofilm.
Online: 2 April 2021 (11:15:54 CEST)
Streptococcus mutans is a key bacterium in dental caries- one of the most prevalent chronic infectious diseases. Conventional treatment both fails to specifically target the pathogenic bacteria and at-tempts to eradicate commensal bacteria as well. Thus, caries remains one of most common and challenging diseases. The use of bacterial viruses as anti-bacterial agents, is gaining interest worldwide. Hardly any phages were described against S. mutans. The objective of this study was to isolate anti-S. mutans phages and to characterize their antimi-crobial properties. Human saliva samples were filtered and screened for potential phages. Standard double-layered agar method was used for isolation. Whole genome sequence analysis and morphology visualization by TEM, were used for anti-S. mutans phage identification. Antibacterial properties were evaluated using clinical strains and ATCC strains of S. mutans in various states. Antibacterial effect was also tested on human cariogenic dentin. One phage against S. mutans was isolated and termed SMHBZ8. This phage showed effective lytic activity in vitro against both planktonic and biofilm S. mutans cultures. Moreover, the phage showed antibacterial effect when used on cariogenic dentin. The isolation and characterization of SMHBZ8 may be the first step in developing a potential phage therapy for dental caries.
ARTICLE | doi:10.20944/preprints202012.0402.v1
Subject: Medicine & Pharmacology, Allergology Keywords: digital guides; CAD/CAM; metal sleeves; dental implants; time of surgery
Online: 16 December 2020 (10:18:10 CET)
Both types of surgical guides – with and without metal sleeves are founded beneficial in clinical studies. The aim of this in vitro study was to compare time of surgical procedure in dental implantology depending of used type of the surgical guide. Ten three dimensional (3D) printed models of lower jaws were prepared based on complete virtual model of patient clinical conditions with missing teeth 37, 46 and 47. Five of this models were used for implant sites preparation performed with use of surgical guide without metal sleeves and dedicated surgical kit, and next five were used for the same procedure performed with surgical guide with metal sleeves and dedicated surgical kit. Time of implant site preparation were measured and noted. Statistical analysis was performed using Student’s t test for independent samples. Difference of time in both groups were founded as statistically significant (t=-9.94; df =28; p=0.0000). Type of surgical guide is important factor which can impact on time of implant site preparation and all surgical procedure.
Subject: Medicine & Pharmacology, Dentistry Keywords: tissue-level; bone-level; dental implants; transmucosal; marginal bone loss; review
Online: 13 July 2020 (03:18:26 CEST)
Purpose: to assess any differences on marginal bone loss between bone-level or tissue-level dental implants through a review of literature until September 2019. Materials and methods: MEDLINE, Embase and other database were searched by two independent authors. The search was limited to articles in English. Results: The search provided 1028 records and, after removing the duplicates through titles and abstracts screening, 45 full-text articles were assessed for eligibility. For qualitative analysis 20 articles were included, 17 articles of them for quantitative analysis. A total of 1161 patients (mean age 54,4 years) and 2933 implants were observed, 1427 (Tissue-level) and 1506 (Bone-level). The survival rate and the success rate were more than 90%, except for 2 studies with a success rate of 88% and 86.2%. No studies reported any differences between groups in term of success and survival rates. Three studies showed that BL-implants had statistically less marginal bone loss (P< 0.05). Only one study reported statistically less marginal bone loss in TL-implants (P< 0.05). In the most part of the studies, differences between implant types in marginal bone loss were not statistically significant. Conclusion: Despite to the peri-implant tissue around transmucosal implants has been reported to be inﬂammation-free because of the absence of bacterial infiltration in the micro-gap between the fixture and abutment, no clinical and radiological differences were highlighted between groups from the included studies after a variable period of follow-up ranged between 1 to 5 years.
CASE REPORT | doi:10.20944/preprints202006.0363.v1
Subject: Medicine & Pharmacology, Dentistry Keywords: Oral lichen planus; Koebner phenomenon; mechanical trauma; dental cusps; psychological distress
Online: 30 June 2020 (10:09:06 CEST)
Mucosal irritation caused by cusps of upper and lower teeth represents a source of persistent, low grade mechanical trauma. This type of trauma can initiate and/or perpetuate oral lichen planus in a few susceptible patients. Here, we report a rare case of bilateral white linear striations in the buccal mucosa of a young patient, associated with sharp cusps. Oral lesions demonstrated a unique cuspal signature highlighting the causal role of subtle mucosal trauma in the genesis of reticular-oral lichen planus. Lesions appeared to be exacerbated by significant psychological distress experienced by the patient. Although the Koebner phenomenon is well reported in the cutaneous lichen planus literature, such presentations are relatively rare in the oral cavity. This report emphasizes the potential role of low-grade cuspal trauma/irritation in conjunction with psychological distress in the genesis of oral lichen planus.
Subject: Chemistry, Electrochemistry Keywords: titanium dental implant; vitamin D3; bioactive coating; anticorrosion protection; EIS; DFT
Online: 10 September 2019 (11:35:26 CEST)
In recent years extensive studies have been continuously undertaken on the design of bioactive and biomimetic dental implant surfaces due to the need for improvement of the implant-bone interface properties. In this paper, the titanium dental implant surface was modified by a bioactive vitamin D3 coating prepared by self-assembly process. Surface characterization of the modified implant was performed by field emission scanning electron microscopy (FE-SEM), attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), and contact angle measurements (CA). Implant’s electrochemical stability during exposure to an artificial saliva solution was monitored in situ by electrochemical impedance spectroscopy (EIS). Experimental results obtained were corroborated by means of quantum chemical calculations at the density functional theory level (DFT). The formation mechanism of the coating onto the titanium implant surface was proposed. During a prolonged immersion period, the bioactive vitamin D3 coating effectively prevented the underlying titanium from corrosive attack (polarization resistance in order of 107 Ω cm2) with ~95% protection effectiveness.
ARTICLE | doi:10.20944/preprints201801.0152.v1
Subject: Medicine & Pharmacology, Dentistry Keywords: sinus lift; graft bone; finite element analysis; 3D modeling; dental implant
Online: 17 January 2018 (11:15:00 CET)
Purpose: The aim of the present experimental 3D-finite element study was to evaluate the influence of an augmented sinus lift with an additional inserted bone graft block. The bone graft block stabilizes the implant in addition to conventional augmented bone. We placed the block in three different positions. The implants were loaded with axial force and forces secondary to laterotrusion and protrusion. Material and Methods: A simplified U-shaped 3D finite element model of the upper jaw and a more complex anatomical model of the left maxilla were created. The bone graft block was placed in three positions: in the lower third in contact with the sinus floor, the middle, and the upper third of the implant. Van Mises’ stress distribution was calculated and analyzed for the different models. We also compared the complex anatomical model with the simplified one. Results: The position of the bone graft block significantly influences the magnitude of stress distribution. A bone graft block positioned in the upper third or middle of the implant reduces the quantity of stress compared to the reference model without a bone graft block. The low bone graft block position is clearly associated with lower stress distribution in compact bone. We registered no significant differences in stress in compact bone with regard to laterotrusion or protrusion. Conclusions: Maximum values of von Mises stresses in compact bone can be reduced significantly by using a bone graft block. The reduction of stress is nearly the same for positions in the upper third and the middle of the implant. It is much more pronounced when the bone graft block is in the lower third of the implant near the sinus floor, which appeared to be the best position in the present study.
ARTICLE | doi:10.20944/preprints202108.0379.v1
Subject: Engineering, Mechanical Engineering Keywords: Fatigue; oblique loading; axial loading; finite element analysis; 3D-printed dental implant
Online: 18 August 2021 (13:54:49 CEST)
Fatigue analysis plays a vital role in determining the structural integrity and life of a dental implant. With the use of such implants on the rise, there is a corresponding increase in the number of implant failures. As such, the aim of this research paper is to investigate the life of 3D-printed dental implants. The dental implants considered in this study were 3D printed according to the direct metal laser sintering (DMLS) method. Additionally, a finite element model was developed to study their performance, while fatigue life was predicted using Fe-Safe software®. The model was validated experimentally by performing fatigue tests. The life of the dental implants was analysed based on Normal strain and the Brown-Miller with Morrow mean correction factor algorithm. The model revealed that there was a strong correlation between the FEA and the experimental results. The clinical success of 3D-printed dental implant experimentally is 20.51 years and computationally under Normal strain is 19.89 years and Brown-Miller with Morrow mean correction factor is 26.82 years.
COMMUNICATION | doi:10.20944/preprints202102.0438.v1
Subject: Materials Science, Biomaterials Keywords: Biomaterial; Dental composite; Luting agents; Core build-up materials; Application in dentistry
Online: 19 February 2021 (13:25:19 CET)
Composite materials are widely used in the dental field in clinics as biomaterials. For example, it has been used as a biomaterial to repair caries and restore masticatory function, and as a cement to adhere the restoration to the tooth substrate. In order to demonstrate its function, dental biomaterials are measured their mechanical strength. From such basic research, we explained the potential of dental biomaterials, especially flexural strength and modulus of elasticity. Mechanical properties of dental biomaterials similar to those of the tooth, thermal stimulation, and aesthetic elements in the oral cavity. In this part, we will introduce the commercialized products of composites suitable for the characteristics and tooth quality, and provide the reader with the characteristics from the flexural characteristics of the composite materials used in clinical dentistry. In clinical performance, it might be advisable to delay polishing when composite biomaterials are used for luting materials, filling materials and core build-up materials since improved the flexural strength and the flexural modulus of elasticity were displayed after 1-day storage. And it is thought that flexural strength or characteristics is a significant important mechanical property of oral biomaterials.
REVIEW | doi:10.20944/preprints202009.0439.v1
Subject: Medicine & Pharmacology, Dentistry Keywords: KAP; Dental professionals; COVID-19; Pandemic; risk of infection, SARS-CoV-2
Online: 18 September 2020 (12:15:24 CEST)
Background: Dental professions are at high risk of contracting novel corona virus (COVID-19) infections during the dental procedure due to the droplets and aerosols generated during various dental procedures on infected patients. To prevent and avoid the cross-infection of the infection to dental professionals or the patients attending the dental clinic, good knowledge of the infection and its prevention mechanisms is mandatory among the professionals. Until to date, there is no pooled estimate on the knowledge,attitude and practice (KAP) of dental professionals to COVID-19 in the globe. Hence, this study aimed to determine the pooled estimate of KAP of dental professionals in this pandemic disease. Methods: Article search was done electronically using Medline, Scopus, Web of Science, EMBASE, SciELO and Google Scholar from June 1, 2020 to August 20, 2020. All studies that assessed the KAP of dental professionals to COVID-19 were searched and included in this review after passing the inclusion criteria. The pooled analysis of their knowledge (sign and symptom, mode of transmission and prevention mechanisms), attitude (their concern, intention to treat suspected patients) and practice (face mask usage, hand washing and alcohol based hand rub usage, handshaking practice, deferred procedures and checkup of patients temperature) was computed using RevMan 5.3 and random effect model was used. The presence of publication bias was assessed using the funnel plot. Results: Twelve articles with a total of 5,362 study participants were included in this study. The pooled estimate revealed that 59.91% of the dental professionals had good knowledge of the signs and symptoms of COVID-19. Two-third of dental professionals know the prevention mechanisms of the infection, and 70.13% had enough knowledge of the transmission modalities of the infection. The professional attitude revealed that only 36.43% of the participants had intention to treat a patient with cough or suspected COVID-19 (36.43%, 95%CI: 8.57, 64.29). Moreover, 47.85% of the dentists were concerned about their life, and the fate of their profession due to this pandemic disease (47.85%, 95%CI: 26.74, 68.97). The pooled analysis showed only 50.86% (95%CI: 18.64, 83.09) of the study participants worn face mask and 52.63% (95%CI: 10.54, 94.71) had avoided handshaking practice during this pandemic period. Non-emergency dental procedures were canceled by 83.98%. Conclusion: The dental professional KAP is not optimal. Thus, dental professionals should be aware of the recently updated knowledge about COVID-19 and practice according to the standards of treatment guidelines, and the recommended infection control measures in dental settings. Moreover, as saliva and droplets are the major sources of infection, dentists should follow essential protocols to regulate droplet and aerosol contamination in the dental practice
ARTICLE | doi:10.20944/preprints201810.0170.v1
Subject: Materials Science, Biomaterials Keywords: antibacterial; biofilm; caries; dental composite; quaternary ammonium monomers; human in situ study
Online: 9 October 2018 (04:43:45 CEST)
Cariogenic oral biofilms cause a considerable amount of recurrent dental caries around composite restorations every year, resulting in unprosperous oral health status and expensive restorative treatment for many patients. Quaternary ammonium monomers that can be copolymerized with the current dental resin systems have been increasingly explored for modulation of dental plaque biofilm growth over dental composite surfaces. Here, we investigated the effect of bis(2-methacryloyloxyethyl) dimethylammonium bromide (QADM), against human overlying mature oral biofilms grown intra-orally in human participants for 7 and 14 days, for the first time. Seventeen volunteers wore palatal devices containing composite specimens containing 10% by mass of QADM or a control composite without QADM. After 7 and 14 days, the adherent biofilms were collected for determination of bacterial counts via colony-forming unit (CFU) counts. The biofilm viability, chronological changes, and percentage coverage were also determined by live/dead staining. QADM composites caused a significant inhibition of S. mutans biofilm formation for up to seven days. No difference in the CFU values were found for the 14-day period. Our findings suggest that (1) QADM composite was successful in inhibiting 1-3 day biofilms in the oral environment in vivo; (2) QADM significantly reduced the portion of S.mutans group in a time course where patients at high risk of caries would develop initial enamel carious lesions; and (3) stronger antibiofilm activity is required for the control of mature long-term cariogenic biofilms. These results provide a perspective on the value of integrating bioactive restorative materials with traditional caries management approaches into clinical practice. Contact-killing strategies via dental materials aiming to prevent or at least reduce high numbers of cariogenic bacteria seem to be a promising approach in patients at high risk of recurrence of dental caries around composites.
ARTICLE | doi:10.20944/preprints202201.0049.v2
Subject: Medicine & Pharmacology, Dentistry Keywords: dental pattern; forensic anthropology; forensic odontology; forensic dentistry; forensic radiolo-gy; forensic chemistry; forensic science; machine learning; identification; dental materials; acid solution; dissolution; sulfuric acid; dentition; teeth; acid degradation
Online: 24 February 2022 (03:41:16 CET)
(1) Teeth, represent in humans the most resilient tissues. However, exposure to concentrated acids might lead to their obliteration, thus making human identification difficult. Teeth often contain dental restorations from materials that are even more resilient to acid impact. This paper introduces novel method of 3D reconstruction of dental patterns as a crucial step for digital identification with dental records.; (2) With combination of modern methods of Micro-Computer Tomography, Cone Beam Computer Tomography, Attenuated Total Reflection in conjunction with Fourier-Transform Infrared Spectroscopy and Artificial Intelligence Convolutional Neural Network algorithms, the paper presents the way of 3D dental pattern reconstruction and human remains identification. Research studies morphology of teeth, bone, and dental materials (Amalgam, Composite, Glass-ionomer cement) under different periods of exposure to 75% sulfuric acid; (3) Results reveal significant volume loss in bone, enamel, dentine, and as well glass-ionomer cement. Results also reveal significant resistance of composite and amalgam dental materials to sulfuric acid impact, thus serving as strong parts in the dental pattern mosaic. Paper also introduces probably first successful artificial intelligence application in automated forensic CBCT segmentation.; (4) Interdisciplinary cooperation utilizing mentioned technologies can solve problem of human remains identification with 3D reconstruction of dental patterns and their 2D projections over existing ante-mortem records.
ARTICLE | doi:10.20944/preprints202301.0304.v1
Subject: Engineering, Biomedical & Chemical Engineering Keywords: Disease Dental Caries; Gradient Boosting Decision Tree; Feature Selection; Machine Learning; Feature importance
Online: 17 January 2023 (09:25:45 CET)
Caries is a prevalent oral disease that primarily affects children and teenagers. Advances in ma-chine learning have caught the attention of scientists working with decision support systems to predict early tooth decay. Current research has developed machine learning algorithm for caries classification and reached high accuracy especially in ML for image data. Unfortunately, most studies on dental caries only focus on classification and prediction tasks, meanwhile dental carries prevention is more important. Therefore, this study aims to design an efficient feature for decision support system machine learning based that can identify various risk factors that cause dental caries and its prevention. The data used in the research work was obtained from the 2018 Korean Children's Oral Health Survey, which totaled nine datasets. The experimental results show that combining the mRMR and GINI Feature Importance methods when training with the GBDT model achieved the optimum performance of 95%, 93%, 99%, and 88% for accuracy, F1 score, precision, and recall, respectively. So, the proposed method has provided effective predictive model for dental caries prediction.
ARTICLE | doi:10.20944/preprints202301.0074.v1
Subject: Medicine & Pharmacology, Dentistry Keywords: Clinical Skills; Clinical Training; Competency; Cross-sectional Studies; Dental Education; Dentistry; Self-perception.
Online: 4 January 2023 (08:48:49 CET)
The transition from undergraduate dental student to the actual practicing dentist is a crucial phase and ensuring the preparedness of graduates for the complexity and demands of contempo-rary dental practice is a challenging task. This study aimed to evaluate the self-perceived prepar-edness of undergraduate dental students and house officers in the dental colleges of Pakistan. Cross-sectional national study was planned to collect the information from dental students and new graduates in Pakistan. The pre-validated Dental Undergraduates Preparedness Assessment Scale (DU-PAS) was used. Purposive sampling technique was utilized to recruit house officers and undergraduate dental students from 27 dental schools in Pakistan. The data analysis was car-ried out using the R statistical environment for Windows (R Core Team, 2015). The total of 862 responses with 642 females and 219 males were analyzed in the study. Overall, clinical skills score was 30.56+9.08 and score for soft skills was 30.54+10.6. The mean age of the participants was 23.42+1.28. Deficiencies were reported in various soft skills and clinical skills attributes.The results highlighted the strengths and weaknesses of dental students and new graduates in Pakistani den-tal institutions. The findings may be used to further develop and strengthen teaching and training of dental students in Pakistan.
ARTICLE | doi:10.20944/preprints202203.0073.v1
Subject: Medicine & Pharmacology, Dentistry Keywords: focus group; patient reported outcome measures; oral health; education; COVID-19; dental problem
Online: 4 March 2022 (07:08:57 CET)
This study reports results of focus groups with school nurses and teachers from elementary, middle, and high schools to explore their perceptions of child and adolescent oral health. Participants included 14 school nurses and 15 teachers (83% Female; 31% Hispanic, 21% White, 21% Asian, 14% African American, and 13% Others). Respondents were recruited from Los Angeles County schools and scheduled by school level for six one-hour focus groups, using Zoom. Audio recordings were transcribed, reviewed, and saved with anonymization of speaker identities. NVivo software was used to facilitate content analysis and identify key themes. The nurses’ rate of “Oral Health Education” comments statistically exceeded that of teachers, while teachers had higher rates for “Parental Involvement” and “Mutual Perception” “Need for Care” was perceived to be more prevalent in immigrants to the United States based on student behaviors and complaints. “Access to Care” was seen as primarily the nurse’s role. Strong relationships between community clinics and schools were viewed by some as integral to students achieving good oral health. The results suggest dimensions and questions important to item development for oral health surveys of children and parents to address screening, management, program assessment, and policy planning.
ARTICLE | doi:10.20944/preprints202109.0221.v1
Subject: Engineering, Biomedical & Chemical Engineering Keywords: quasi-static load; abutment screw; dental implant; finite element method; dynamic load; mesiodistal
Online: 13 September 2021 (15:55:30 CEST)
Variations in the implant thread shape and occlusal load behavior may result in significant changes in the biological and mechanical properties of dental implants and surrounding bone tissue. Most previous studies consider a single implant thread design, an isotropic bone structure, and a static occlusal load. However, the effects of different thread designs, bone material properties, and loading conditions are important concerns in clinical practice. Accordingly, the present study performs Finite Element Analysis (FEA) simulations to investigate the static, quasi-static and dynamic response of the implant and implanted bone material under various thread designs and occlusal loading directions (buccal-lingual, mesiodistal and apical). The simulations focus specifically on the von Mises stress, displacement, shear stress, compressive stress and tensile stress within the implant and the surrounding bone. The results show that the thread design and occlusal loading rate have a significant effect on the stress distribution and deformation of the implant and bone structure during clinical applications. Overall, the results provide a useful insight into the design of enhanced dental implants for an improved load transfer efficiency and success rate.
ARTICLE | doi:10.20944/preprints202107.0501.v1
Subject: Materials Science, Biomaterials Keywords: Dental implants; Thermal stress; Modeling of heat transfer; Temperature changes; Heat equation; Analytical solution.
Online: 21 July 2021 (15:37:53 CEST)
Introduction: Heat is a kinetic process whereby energy flows from between two systems; hot-to-cold objects. In oro-dental implantology, conductive heat transfer/(or thermal stress) is a complex physical phenomenon to analyze and consider in treatment planning. Hence, ample research has attempted to measure heat-production to avoid over-heating during bone-cutting and -drilling for titanium (Ti) implant-site preparation and insertion, thereby preventing/minimizing early (as well as delayed) implant-related complications and failure. Objective: Given the low bone-thermal conductivity whereby heat generated by osteotomies is not effectively dissipated and tends to remain within the surrounding tissue (peri-implant), increasing the possibility of thermal-injury; this work attempts to obtain an exact analytical solution of the heat equation under exponential thermal-stress, modeling transient heat transfer and temperature changes in Ti implants upon hot-liquid intake. Materials and Methods: We investigate the impact of the material, the location point along implant length, and the exposure time of the thermal load on temperature changes. Results: Despite its simplicity, the presented solution contains all the physics and reproduces the key features obtained in previous numerical analyses studies. To the best of knowledge, this is the first introduction of the intrinsic time, a “proper” time that characterizes the geometry of the dental implant, where we show, mathematically and graphically, how the interplay between “proper” time and exposure time influences temperature changes in Ti implants, under the suitable initial and boundary conditions. Conclusions: This work aspires to accurately complement the overall clinical diagnostic and treatment plan for enhanced bone-implant interface, implant stability and success rates, whether for immediate or delayed loading strategies.
ARTICLE | doi:10.20944/preprints202210.0136.v1
Subject: Medicine & Pharmacology, Dentistry Keywords: Rural dental care; Preventive visits; Rural Vs Urban; community health centers; Hispanic Vs Non-Hispanics
Online: 11 October 2022 (04:07:45 CEST)
Abstract: Background: To determine the impact of a patient's ethnicity on the seeking preventive dental services at the Community Health Centers (CHCs) in South-Central Texas. Methods: Pri-mary electronic health records (HER) data were collected regarding each patient's medical and dental history, and comprehensive treatment planning. The researchers retrieved EHR from Jan-uary 2016 to 2022. Bivariate analysis was completed to test outcome with predicator and covariates using appropriate statistical tests. A multiple linear regression model was used to understand the association between the predictor and outcome variable while controlling for confounders. Results: The study findings revealed significantly higher dental visits (2.26 ± 2.88) for Hispanic patients. The results from the multiple regression model indicated that non-Hispanic patients had a 8% fewer chance of visiting the CHCs for preventive dental services compared to the Hispanic population (p-value<0.001) when all other variables are held constant. However, the study results were not significant as the effect size was small to conclude the effect of ethnicity on the patients visiting the dental clinic at the CHCs for preventive services. Conclusion: The study concluded that there is no difference in the preventive dental services completed by Hispanics and Non-Hispanics when all other variables are controlled.
ARTICLE | doi:10.20944/preprints202007.0752.v1
Subject: Materials Science, Biomaterials Keywords: self-etching two bottled dental adhesive; 10-methacryloyloxidecyl dihydrogen phosphate monomer; biocompatibility; shear bond strength
Online: 31 July 2020 (13:56:28 CEST)
Dentin bonding is a key in restorative dentistry. Herein, we developed self-etching two-bottle adhesive system containing 10-methacryloyloxidecyl dihydrogen phosphate monomer (MDP) and the physical, mechanical, and biocompatible properties were evaluated. The characteristics of MDP were analyzed using nuclear magnetic resonance (NMR). The water sorption and solubility, the shear-bond strengths to dentin and enamel, and cytotoxicity tests were performed. The newly blended experimental group showed the lowest thickness and water sorption and solubility values. The shear bond strength to enamel and dentin were comparable to control groups (the three other products) all test groups showed 60% of cell viability. In this study, the properties of the newly synthesized adhesive are comparable with the others. The fundamental goal of this study is to get the MDP patent released, as it is intended for domestic production. For this purpose, this dentin adhesive was developed and compared with the commercial product.
ARTICLE | doi:10.20944/preprints202203.0378.v1
Subject: Medicine & Pharmacology, Other Keywords: COVID-19; pandemic; impact; healthcare; lockdown; movement control order; Malaysia; medical services; dental services; pharmacy services
Online: 29 March 2022 (09:45:10 CEST)
Malaysia implemented a movement control order (MCO) to curb the spread of the SARS-CoV-2 virus in March 2020. Despite healthcare services remaining operational, rising COVID-19 infections and MCO restrictions have forced healthcare professionals to seek a compromise between service capacity and standard operating procedure compliance. A cross-sectional survey was conducted among public and private sector doctors, dentists and pharmacists to determine how lockdown measures impacted healthcare services. Responses from 413 doctors, 193 dentists, and 163 pharmacists were analysed. Pharmacy services remained mostly unaffected throughout the MCO. In contrast, operational capacities for surgical and dental services were severely affected during the MCO. All service sectors reported restricting patients or accompanying individuals at the workplace, reductions in staffing capacity, and shortened patient contact time at various degrees. Many pharmacy and medical participants reported supplying extended medication supplies to patients. Adoption of virtual healthcare services was generally poor. All private service sectors suffered financial losses ranging between 59 to 75%. Periodic assessments of the healthcare system throughout the pandemic are required to identify which patients have their treatment compromised so that healthcare managers and policy makers can plan and implement appropriate interventions that help alleviate pressure within the health system.
REVIEW | doi:10.20944/preprints202008.0557.v1
Subject: Medicine & Pharmacology, Dentistry Keywords: transplantation; dental implant; marginal bone loss; implant failure rate; systematic review; periodontitis; periodontal diseases; oral health
Online: 25 August 2020 (13:45:34 CEST)
This systematic review investigates the failure rate and marginal bone loss (MBL) of dental implants placed in Solid-organ transplant (SOT) patients compared to healthy controls. Three databases (PubMed, Web of Sciences and the Cochrane Library) were searched up to June 2020 (PROSPERO CRD42019124896). Case-control and cohort studies reporting data failure rate and marginal bone loss (MBL) of dental implants placed in SOT patients were included. The risk of bias of observational studies was assessed through the Newcastle-Ottawa Scale (NOS). Four case-control studies fulfilled the inclusion criteria, all of low risk of bias. Meta-analyses revealed consistently lower implant failure rate than control populations at patient and implant levels. SOT patients had a significant difference of -18% (p-value <0.001) of MLB towards healthy patients. SOT status poses no serious threat to implant survival. Overall, this group of patients presented lower levels of dental implant failure rate and marginal bone loss compared to otherwise healthy patients. Further intervention trials with wider sample size and longer follow-ups are necessary to confirm these summary results.
ARTICLE | doi:10.20944/preprints201908.0143.v1
Subject: Life Sciences, Other Keywords: acid-etching; micro-rough; bone regeneration; sub-micro-rough; bone integration; osseointegration; dental implants; orthopedic implants
Online: 12 August 2019 (12:35:48 CEST)
Titanium micro-scale topography results in excellent osteoconductivity and bone-implant integration. However, the biological effects of sub-micron topography are unknown. We compared osteoblastic phenotypes and in vivo bone and implant integration abilities between titanium surfaces with micro- (1–5 µm) and sub-micro-scale (0.1–0.5 µm) topographies and machined titanium. Average roughness was 12.5 ± 0.65 nm, 123 ± 6.15 nm, and 24 ± 1.2 nm for machined, micro-rough, and sub-micro-rough surfaces, respectively. The micro-rough surface showed the fewest cells attaching during the initial stage and the lowest proliferation. Calcium deposition and expression of osteoblastic genes were highest on the sub-micro-rough surface and lowest on the machined surface. Bone-to-implant integration was strongest for the micro-rough surface, consistent with it having the greatest ability to retain cells in vitro. Thus, the biological effects of titanium surfaces are not necessarily proportional to the degree of roughness in osteoblastic cultures or in vivo. Sub-micro-rough titanium ameliorates the disadvantage of micro-rough titanium by restoring cell attachment and proliferation and enhances the rate of osteoblastic differentiation over that of micro-rough titanium; however, bone integration and the ability to retain cells are compromised due to its lower interfacial mechanical locking compared to that of micro-rough titanium.
REVIEW | doi:10.20944/preprints202103.0636.v2
Subject: Materials Science, Biomaterials Keywords: Silicon nitride; structure; properties; processing; coatings; spinal implants; arthroplastic implants; bone scaffolds; dental implants; neural circuits; biosensors; medical diagnostics.
Online: 15 April 2021 (12:55:38 CEST)
This topical review describes the results of recent research into and development of silicon nitride, a ceramic material with unique properties. The outcome of this ongoing research strongly encourages the use of monolithic silicon nitride and coatings as contemporary and future biomaterial for a variety of medical applications. Crystallographic structure, synthesis and processing of monolithic structures and coatings, and examples of their medical applications are covered that relate to spinal, orthopedic and dental implants, bone grafts and scaffolds, platforms for intelligent synthetic neural circuits, antibacterial and antiviral particles and coatings, optical biosensors, and nano-photonic waveguides for sophisticated medical diagnostic devices. The examples provided show convincingly that silicon nitride is destined to become a leader to replace titanium and other entrenched biomaterials in many fields of medicine.
REVIEW | doi:10.20944/preprints202009.0254.v1
Subject: Medicine & Pharmacology, Behavioral Neuroscience Keywords: dental care; emotions; health personnel; health services; human needs; motivation; patient reported outcome measures; patient satisfaction; personal satisfaction; theory of satisfaction
Online: 11 September 2020 (09:44:11 CEST)
There is little understanding of patients' experiences and perceptions with satisfaction by health professionals such as medical and dental clinicians. Furthermore, patient satisfaction is not well understood. The objective of this article is to better understand patients' satisfaction with their medical and dental care. The methods of the current article are based on a narrative review of the literature strategy. Patient satisfaction's multidimensional nature has been established since the perceived reasons for satisfaction varied widely among patients. Many aspects of the treatment influence participant satisfaction at different stages of the intervention's process. An improved understanding of the basis for managing patients' expectations with information reiteratively and efficiently may ultimately reduce patients' potential for negative feelings toward the medical and dental treatment experience. The consumerist method may misrepresent the concept of satisfaction in health service.
ARTICLE | doi:10.20944/preprints202104.0744.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: Aerosols; dental clinics; infection control; high-volume evacuation; extra-oral suction device; particle concentration; sensor network; dispersion modeling; exposure assessment; air quality
Online: 28 April 2021 (10:32:57 CEST)
Human exposure to infectious aerosols results a transmission of diseases, such as influenza, tuberculosis, and COVID-19. Most dental procedures generate a significant number of aerosolized particles, increasing transmission risk in dental settings. Since the generation of aerosols in dentistry is unavoidable, many clinics started using intervention strategies such as area-filtration units and extraoral evacuation equipment, especially under the relatively recent constraints of the pandemics. However, the effectiveness of these devices in dental operatories has not been studied. Therefore, the dental personnel's ability to position and operate such instruments efficiently is also limited. To address these challenges, we utilized a real-time sensor network for assessment of aerosol dynamics during dental restoration and cleaning producers with and without intervention. The strategies tested during the procedures were (i) local area high-efficiency particle air (HEPA) filters and (ii) extra-oral suction device (EOSD). The study was conducted at the University of Washington School of Dentistry using a network of thirteen fixed sensors positioned within the operatory and one wearable sensor worn by the dental operator. The sensor network provides time and space-resolved particulate matter (PM) data. Three-dimensional (3D) visualization informs aerosol persistence in the operatory. It was found that area filters did not improve the overall aerosol concentration in dental offices significantly. An average of 16% decrease in PM concentration was observed when EOSD equipment was used during the procedures. The combination of real-time sensors and 3D visualization can provide dental personnel and facility mangers with actionable feedback to effectively assess aerosol transmission in medical settings and develop evidence-based intervention strategies.