The objective of this study was to compare the distribution of stress in the maxillary bone, dental implants, and prosthetic components supporting implant-supported maxillary overdentures with partial palatal coverage, in both splinted and unsplinted designs. Two models of maxillary overdentures were designed using the Exocad Dental CAD program, which included cancellous and cortical bone. The complete denture design and abutments (locator abutments in the unsplinted and Hader bar with Vertix attachments placed distally in the splinted variant) were also designed. The denture material was PEEK (Polyetheretherketone), and the method used to analyze patient-specific 3D X-ray scans was 3D QCT/FEA (Three-dimensional Quantitative Computed Tomography-Based Finite Element Analysis). Loading was divided into three load cases: frontal region (both incisors of the denture) and distal region (both molars and first premolar of the denture). The forces applied were 150 N with an oblique component with a buccal inclination of 35° in the frontal region, and 600 N with a buccal inclination of 5° (molars) or solely vertical (premolar) in the distal region. The model with locator abutments showed higher stresses in all load cases in both analyzed implant variants and in the maxilla. The differences in stress distribution between the splinted and unsplinted variants were more significant in the distal region. According to the results of the present study, the amount of stress in bone tissue and dental implant parts was smaller in the splinted, bar-retained variant. The findings of this study can be useful in selecting the appropriate prosthetic design for implant-supported maxillary overdentures with partial palatal coverage.

Dental-implant-supported reconstructions provide comfort and improvements in prosthetic function, adaptation, and stability over conventional treatment options. The objective of this study was to evaluate the effect of multiple cleaning solutions on dentures and their influence on the deterioration and loss of retention of overdenture attachments in a 12-month clinical-use simulation. In this way, four different brands of retentive caps made of Teflon (OT Equator, Locator®, Kerator®, and Locator R-Tx®) were immersed in five different cleaning solutions (Kukident®, Benfix®, Corega®, and Protefix®), and tap water was used as the control group, in a simulation that lasted 12 months. Data were analyzed using two-way ANOVA and a Tukey HSD. Furthermore, a Levene Test and Shapiro–Wilk tests were performed to assess the validation of the ANOVA assumptions. The statistical analysis was performed using R version 4.2.2 software with the significance level set to p < 0.05. There were significant statistical differences between the different manufacturers on the retention forces of the attachment’s retentive caps. For the cleaning solution groups, different statistical results between Kukident® and Benfix® were observed. There were no significant statistical differences between Corega®, Protefix®, and tap water despite the fact that the retention forces decreased in all of them.

Purpose: this paper evaluates the effect of thermo-formed aligners with complementary biomechanical attachments (CBA) on periodontal ligaments (PDL) during the expansion process of the maxillary arch using simulations based on the finite element method (FEM). Methods: four types of teeth (canine 3, premolar 4, premolar 5 and molar 6) were modeled using 3D CAD. In addition, aligners, CBAs and PDL were also 3D modeled. With this information, a FEM model was generated, and a clinical rehabilitation scenario was simulated. For the validation of the results, a comparison with medical records was performed. Results: for canine 3, the displacement was 0.134 mm with a maximum stress of 4.822 x10-3MPa in the amelocemental junction. For premolar 4, the displacement was 0.132 mm at a maximum stress of 3.273x10-3MPa in the amelocemental junction. Premolar 5 had a displacement of 0.129 mm and a stress of 1.358 x10-3MPa at 1 mm from the amelocemental junction. Molar 6 had a displacement of 0.124 mm and a maximum stress of 2.440 x10-3MPa. Conclusions: The simulations showed that the use of CBA reduces tooth tipping. The model with Vestibular CBA presented the best results in terms of the dental movement of expansion of the maxillary arch with the use of thermoformed aligners. Significance: Considering the difficulty of performing in vivo tests that evaluate the configuration effectiveness of the different CBA alternatives in thermoformed aligners, FEM techniques were used to reduce time and costs, and get accurate results with minimal errors.

The United Arab Emirates (UAE) has established itself as the medical device industry’s preferred regional center. Major multinational corporations either have a regional subsidiary or are planning to open up a principal office in the UAE to expand their business. Employees in the industry are in high demand as new opportunities open up frequently and that causes challenges to companies, namely employee turnover. This research helps bridge the gap found in the literature by investigating the factors that impact employee turnover in the medical device industry in the UAE. These factors were tested with their subsequent sub-factors. Using a quantitative approach, the study surveyed 230 participants from 47 medical device companies in the UAE. The result of one-way ANOVA demonstrated a significant relationship between employee salary and employee turnover. The linear regression analysis was statistically significant between perceived external prestige, location, flextime, organizational justice, job satisfaction, organizational commitment, extrinsic rewards, career advancement, lack of alternatives, constituent attachments, and employee turnover. These findings indicate the need for a strategy utilizing these factors for existing and new medical device companies in the UAE to prevent high employee turnover or limit it at least.