Forensic Gender Determination by Using Mandibular Morphometric Indices an Iranian Population: A Panoramic Radiographic Cross-Sectional Study.

Gender determination is the first step in forensic identification, followed by age and height determination, which are both affected by gender. This study assessed the accuracy of gender estimation using mandibular morphometric indices on panoramic radiographs of an Iranian population. This retrospective study evaluated 290 panoramic radiographs (145 males and 145 females). The maximum and minimum ramus width, coronoid height, condylar height, antegonial angle, antegonial depth, gonial angle, and the superior border of mental foramen were bilaterally measured as well as bicondylar and bigonial breadths using Scanora Lite. Correlation of parameters with gender was analyzed by univariate, multiple, and best models. All indices except for gonial angle were significantly different between males and females and can be used for gender determination according to univariate model. Condylar height, coronoid height, and superior border of mental foramen and ramus were still significantly greater in males than in females after controlling for the effect of confounders (p < 0.05). Based on the best model, a formula including five indices of bicondylar breadth, condylar height, coronoid height, minimum ramus width, and superior border of mental foramen was used for gender determination. Values higher than 56% indicate male gender, while lower values indicate female gender, with 81.38% specificity for correct detection of females and 88.97% sensitivity for correct detection of males. Despite the satisfactory results, future research should focus on larger populations to verify the accuracy of the present findings.

Assessment of peri-implant bone stress distribution with the effect of attachment type and implant location using finite element analysis.

Background: The objective of the current research was to evaluate how stress is distributed in the peri-implant bone of a mandibular overdenture with implants placed asymmetrically to the midline. Methods: A 26-year-old male's mandible, with missing teeth, was examined using computed tomography (CT) scanning. Two implants were inserted at right angles to the occlusal plane, in the positions of the right canine and left lateral incisor of the mandible, with an internal connection. Two types of attachments (bar and ball) were designed. To simulate the clinical condition, anterior (on central incisors) and bilateral posterior (on premolars and molars) loadings were applied. The stress distribution was assessed using finite element analysis (FEA). Results: The lateral incisor level implant was found to have the highest maximum principal stress (about 33 MPa) in both models in the anterior loading condition. However, in both models, the canine-level implant revealed more stress values (about 22 MPa) in the posterior loading condition. Conclusion: In mandibular implant-supported overdentures, when implants were placed asymmetrically to the midline, one acted as a fulcrum and sustained more occlusal load. The bar attachment system did not reveal superior results in terms of stress distribution compared to the ball attachment.

The effect of attachment types and implant level on the stress distribution in a mandibular overdenture: a 3D Finite Element Analysis / O efeito dos tipos de sistemas de retenção e nível dos implantes na distribuição de tensões em overdentures mandibulares: Análise por Elementos Finitos 3D

Objective: The objective of this study was to evaluate the stress distribution in bone-surrounding implants placed in different levels in a mandibular overdenture. Material and Methods: A Computerized Tomography (CT) scan of an edentulous mandible was used to generate the models. Two implants with an internal connection were placed perpendicular to the occlusal plane in the Canine sites of the mandible. The implant in the left side was placed 1mm higher than the other side. Dolder bar and ball attachments were designed. Loading was performed by clenching the teeth with reconstruction of the muscles. In the anterior loading condition, force was applied to the central incisors and in the posterior loading conditions, it was applied to the molars and premolars. Then the Maximum Principal Stresses in the peri implant bone was evaluated with finite element analysis. Results:In both models, the highest stress values were recorded in the cortical bone surrounding the higher implant except in the ball model with unilateral load application on the right side (64.7 MPa). In almost all loading conditions the stress value differences in models with bar and ball attachments were low. Only in the anterior loading condition, the stress magnitude was higher in two implants of the ball model (60.5 MPa in the left side and 21 MPa in the right side) compared to the bar model (54.5 MPa in the left side and 17.5 MPa in the right side). Conclusion: The stress concentration did not affected considerably by the attachment system. High stress values were found adjacent the implant with a higher level. To reduce the amount of stress, bilateral balance occlusion should be considered. (AU)

Objetivo: O objetivo deste estudo foi avaliar a distribuição de tensões em tecido ósseo ao redor de implantes instalados em diferentes níveis em uma Overdenture mandibular. Material e Métodos: Uma tomografia computadorizada (TC) de uma mandíbula edêntula foi usada para gerar os modelos. Dois implantes de conexão interna foram instalados perpendicularmente ao plano oclusal na região de caninos inferiores. O implante do lado esquerdo foi instalado 1mm acima do que do lado direito. A barra Dolder e o pilar tipo bola foram projetados. A carga foi realizada apertando os dentes com reconstrução dos músculos. Na condição de carga anterior, a força foi aplicada nos incisivos centrais e nas condições de carga posterior, foi aplicada nos molares e pré-molares. Em seguida, as Tensões Máximas Principais no osso periimplantar foram avaliadas com análise de elementos finitos. Resultados: Em ambos os modelos, os maiores valores de tensão foram registrados ao redor do osso cortical ao redor do implante superior, exceto no modelo tipo bola com aplicação de carga unilateral no lado direito (64,7 MPa). Em quase todas as condições de carregamento, as diferenças nos valores de tensão nos modelos com fixações de barra e tipo bola foram baixas. Apenas na condição de carregamento anterior, a magnitude da tensão foi maior em dois implantes do modelo tipo bola (60,5 MPa no lado esquerdo e 21 MPa no lado direito) em relação ao modelo barra (54,5 MPa no lado esquerdo e 17,5 MPa no lado direito). Conclusão:A concentração de tensão não foi afetada considerando o sistema de retenção. Maiores valores de tensão foram encontrados adjacentes ao implante com um nível mais alto. Para reduzir a quantidade de tensão, a oclusão bilateral balanceada deve ser considerada.(AU)

Efficiency of Erbium-Doped Yttrium Aluminum Garnet Laser in Debonding Cemented Glass Fiber Posts: an in vitro Study.

STATEMENT OF THE PROBLEM: The efficacy of erbium-doped yttrium aluminum garnet (Er; YAG) laser on the debonding properties of certain post materials has remained largely unexplored. PURPOSE: This study aimed to investigate the effect of Er; YAG laser irradiation on debonding of cemented glass fiber posts in root canal treated teeth. MATERIALS AND METHOD: In this in vitro study, forty root canal treated mandibular premolar teeth were used in this study. Glass fiber posts were bonded using Panavia F 2.0 cement in the root canal space, and samples were divided into two groups. In the test group, samples were exposed to laser radiation of 7W, 350mJ, frequency of 20Hz and discontinued washing spray. In the control group, samples were left untouched. In each group, samples were sectioned into 1.5mm thick slices from the coronal, middle, and apical thirds of the root (N=120). Tensile bond strengths were evaluated using the push-out test and the failure patterns were evaluated using scanning electron microscopy (SEM). To compare the laser and non-laser groups at each location, independent sample t test was applied, and to compare bond strength between the locations in each group, one-way ANOVA and Tukey's HSD post hoc was applied. RESULTS: A significant difference in tensile strength was observed between the laser-irradiated group and control group; tensile bond strength was much higher in the control group (p<0.001). The highest frequency of fractures was observed at the cement-dentin interface. Given the used parameters, complete debonding was not achieved in the laser-irradiated group. CONCLUSION: Laser radiation reduced the bond strength of glass fiber posts to resin cement without complete debonding.