: In this study we evaluated, if single nucleotide polymorphisms (SNPs) in the genes encoding PTH, VDR, CYP24A1 and CYP27B1 are associated with Mandibular Retrognathism (MR). Samples from biologically-unrelated patients receiving orthodontic treatment were included in this study. Pre-orthodontic lateral cephalograms were used to determine the phenotype. Patients having a retrognathic mandible (SNB<78º) were selected as cases and those with an orthognathic mandible (SNB=78º–82º) were selected as controls. Genomic DNA was used for genotyping analysis of SNPs in PTH (rs694, rs6256 and rs307247), VDR (rs7975232), CYP24A1 (rs464653) and CYP27B1 (rs927650). Chi-squared or Fisher’s tests were used to compare genotype and allele distribution among groups. Haplotype analysis was performed for the SNPs in PTH. The established alpha was p<0.05. Multifactor dimensionality reduction (MDR) was used to identify SNP-SNP interactions. A total of 48 MR and 43 controls were included. In the genotype and allele distribution analysis, the SNPs rs694, rs307247 and rs464653 in were associated with MR (p<0.05). MDR analyses predicted the best interaction model for MR was rs694-rs927650, followed by rs307247-rs464653-rs927650. Some haplotypes in the PTH gene presented statistical significance. Our results suggest that SNPs in PTH, VDR, CYP24A1 and CYP27B1 genes are associated with the presence of mandibular retrognathism.

Liver is the sixth most common site of primary malignant tumors, and the third leading cause of cancer death worldwide. Hepatocellular carcinoma is the most common primary liver malignancy and lungs, abdominal lymph nodes and adrenal glands are the most common sites of its metastasis. We present a rare case of an isolated metastasis of a hepatocellular carcinoma in the left mandibular ramus, with regards to its clinical and radiological presentation and with regards to possible routes of the metastatic spread.

The aim of this study was to create a novel machine learning (ML) algorithm for predicting the post-pubertal mandibular length and Y-axis in females. Cephalometric data from 176 females with Angle Class I occlusion were used to train and test 7 ML algorithms. For all ML methods tested, the mean absolute errors (MAEs) for the 2-year prediction ranged from 2.78-5.40 mm and 0.88-1.48 degrees, respectively. For the 4-year prediction, MAEs of mandibular length and Y-axis ranged from 3.21-4.00 mm and 1.19-5.12 degrees, respectively. The most predictive factors for post-pubertal mandibular length were mandibular length at previous timepoints, age, sagittal positions of the maxillary and mandibular skeletal bases, mandibular plane angle, and anterior and posterior face heights. The most predictive factors for post-pubertal Y-axis were Y-axis at previous timepoints, mandibular plane angle, and sagittal positions of the maxillary and mandibular skeletal bases. ML methods were identified as capable of predicting mandibular length within 3 mm, and Y-axis within 1 degree. Compared to each other, all of the ML algorithms were similarly accurate, with the exception of MLP regressor.

The problem of filling the bone cavity remains relevant in maxillofacial and oral surgery. There is a large selection of osteotropic materials of various natures for filling of bone defects of different etiology. The aim of our research was to improve the result of surgical treatment in a patient with a complicated mandibular fracture with the use of collagenic xenograft during osteosynthesis. In this article, we introduce our experience in the treatment of a patient with a complicated mandibular angle fracture in a combination with the follicular cyst. The obligate steps of treatment included stabilization of the bony fragments, a decrease of risk in fracture line malposition along with titan mini- plates, and shortening in the time of bone regeneration due to a filling of bone defect with the osteotropic material. This approach allowed us to reduce the rehabilitation period and further prosthetic treatment after 4-5 months without additional bone grafting manipulations. Though, the use of collagen osteotropic material, possessing osteoconductive properties, can improve the treatment of patients with mandibular fractures.

The paper aims in assessing risks of mandible fractures consequent to impacts or sport accidents. The role of the structural stiffness of mandible, related to disocclusion state, is evaluated through numerical simulations using the finite element method (FEM). It has been assumed that the quasi-static stress field, due to distributed forces developed during accidents, could explain the common types of mandibular fractures. Geometric model of adolescent mandible was built, upon the basis of medical imaging, in CAD software with distinction between cortical layer and inner spongy bone. The finite element model of disoccluded mandible was next created. Mandibular condyles were supposed jammed in the maxillary fossae. The total force of 700 N, simulating an impact on mandible, has been sequentially applied in three distinct areas: centrally, at canine zone and at the mandibular angle. Clinically most frequent fractures of mandible were recognized through the analysis of maximal principal stress and maximal principal strain fields. Mandibular fracture during accidents can be analyzed at satisfactory level using linear quasi-static FE models for designing protections in sport and transport. The proposed approach can be improved by introducing more realistic interactions between condylar processes and fossae.

Introduction The placement of implants is often hindered by a severely atrophic mandibular edentulous ridge. A sufficient volume of bone graft is crucial for successful implant restoration. The required bone graft volume directly correlates with the deficiency present in the edentulous ridge. If the residual crestal bone height is so low that the distance between the crestal ridge and the inferior alveolar nerve is less than 2 mm, a significant bone augmentation procedure is necessary. This procedure must ensure the implants are surrounded by a sufficient margin of bone, aiming for a final height of more than 8 mm and a width of more than 7 mm. Achieving primary closure with adequate soft tissue is vital for the success of the bone graft procedure. The key to successful bone grafting lies in the effective management of the soft tissue covering. Case Report This case report details the treatment of a patient with severely atrophic edentulous ridges on both sides, addressed using Self Inflating Tissue Expanders (SITEs) to facilitate bone grafting and implant placement. Following soft tissue expansion, bone grafting and implant placement were successfully performed. The implants supported a fixed restoration, which remained stable and complication-free over a seven-year observation period. Conclusion The SITE (Self-Inflating Tissue Expander) proved effective in obtaining a substantial amount of bone graft needed for implant installation. A seven-year follow-up confirmed the implants were well-functioning with stable bone support, healthy soft tissue coverage, and adequate vestibular depth.

The purpose of this study was to investigate the functional load capacity of the periodontal ligament (PDL) in a full arch maxilla and mandible model using numerical simulation. The goal of was to determine the functional load pattern in multi- and single rooted teeth with full and reduced periodontal support. CBCT data were used to create 3D-models of a maxilla and mandible. The DICOM dataset was used to create a CAD-model. For a precise description of the surfaces of each structure (enamel, dentin, cementum, pulp, PDL, gingiva, bone), each tooth was segmented separately, and the biomechanical characteristics were considered. A Finite-Element-Analysis (FEA) software computed the biomechanical behavior of stepwise increased force of 700N in cranial and 350N in ventral direction of the muscle approach of the Masseter muscle. The periodontal attachment (cementum-PDL-bone contact) was subsequently reduced in 1mm increments and the simulation repeated. Quantitative (pressure, tension, and deformation) and qualitative (color-coded images) data were recorded and descriptively analyzed. The teeth with the highest load capacities were the upper and lower molars (0.4-0.6MPa), followed by the premolars (0.4-0.5MPa) and canines (0.3-0.4MPa) when vertically loaded. Qualitative data showed that the area with the highest stress in the PDL were for single rooted teeth the cervical and apical area and for molars additionally the furcation roof. In both, single- and multi rooted teeth the gradual reduction of the bone levels caused an increase of the load on the remaining PDL. Cervical and apical areas as well as the furcation roof are the zones with the highest functional stress. The more bone loss, the higher the mechanical load on the residual periodontal supporting structures.

Background and Objectives: The prevalence of osteoporosis is high, reportedly affecting 200 million people worldwide. A major problem associated with osteoporosis is that femoral fractures cause a decline in general function and loss of independence, greatly reducing patients’ quality of life. Notably, osteoporosis is an asymptomatic chronic metabolic disease, and its detection is thus often delayed. Interestingly, mandibular cortical index (MCI) classification using dental panoramic radiography is reportedly useful for early detection of osteoporosis. However, this visual classification method can lead to differences in diagnosis among surgeons. Therefore, this preliminary study was performed to analyze cone-beam computed tomography (CBCT) data and examine an objective MCI classification using the findings obtained. Materials and Methods: MCI classification (classified as C1, C2, or C3) was performed by three examiners on 70 women (91 sites) aged ≥20 years. The mandibular cortical width of all sites was measured using CBCT images. Results: The results showed that the mandibular cortical width was not particularly correlated with age or number of present teeth, and no significant quantitative differences were found between C1 and C2. However, coronal CBCT images of C2 revealed multiple characteristic bone trabecular structures. Conclusions: These structures may be an important finding affecting the classification of two-dimensional dental panoramic radiography images.

The human mandible's cancellous bone, which is characterized by its unique porosity and directional sensitivity to external forces, is crucial for sustaining biting stress. Traditional CAD models fail to fully represent bone's anisotropic structure and thus depend on simple isotropic assumptions. For our research, we use the latest versions of nTopology and Creo Parametric software to make biomimetic Voronoi lattice models that accurately reflect the complex geometry and mechanical properties of trabecular bone. The porosity of human cancellous bone is accurately modeled in this work using biomimetic Voronoi lattice models. The porosities range from 70% to 95%, which can be achieved by changing the pore sizes to 1.0 mm, 1.5 mm, 2.0 mm, and 2.5 mm. Finite element analysis (FEA) was used to examine the displacements, stresses, and strains acting on dental implants with a buttress thread, abutment, retaining screw, and biting load surface. The results show that the Voronoi model accurately depicts the complex anatomy of the trabecular bone in the human jaw, compared to standard solid block models. The ideal pore size for biomimetic Voronoi lattice trabecular bone models is 2 mm, taking into account both the von Mises stress distribution over the dental implant, screw retention, cortical bone, cancellous bone, and micromotions. This pore size displayed balanced performance by successfully matching natural bone's mechanical characteristics. Advanced finite element analysis (FEA) improves biomechanical understanding of how bones and implants interact by creating more accurate models of biological problems and dynamic loading situations. This makes biomechanical engineering better.