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The aim of this study was to investigate the association between third molar agenesis and mesiodistal crown dimensions in individuals from Germany. The sample consisted of 314 (156 males and 158 females) orthodontic patients, divided into two groups: one group with individuals presenting at least one congenitally missing third molar and a control group with individuals having a full complement of 32 teeth. The mesiodistal crown width of each fully erupted permanent tooth was measured at its maximum dimension. The t-test was used to compare mesiodistal width between groups, with additional analyses according to gender and dental arch. A chi-square test evaluated the distribution of third molar agenesis among genders, and odds ratios (OR) with 95% confidence intervals (CI95%) were calculated. Pearson correlation assessed the relationship between the number of missing third molars and mesiodistal crown size. A total of 89 patients with third molar agenesis and 225 controls were included. Forty-three males and 46 females presented agenesis; with no significant association between gender and third molar agenesis (p = 0.760; OR = 1.08; 95% CI = 0.66–1.73). Mesiodistal dimensions were significantly different between males and females (p < 0.05). Patients with third molar agenesis exhibited a significant reduction (p < 0.05) in mesiodistal size across all teeth, most notably in second molars and maxillary lateral incisors. In males, all teeth in the agenesis group showed smaller dimensions compared to controls, with differences ranging from −0.43 to −0.15, the largest observed in the second maxillary molars (−0.43). In females, 18 of 28 teeth showed significant reductions, ranging from −0.42 to 0.00, with the largest difference in the left second mandibular molar (−0.42). The correlation between the number of missing third molar and mesiodistal size showed some negative moderate correlations, especially for lower canines (left r = −0.459, and right r = −0.534). In conclusion, third molar agenesis is associated with reduced mesiodistal crown dimensions in individuals from Germany, with this effect being more pronounced in males than in females.

Age estimation is a crucial step in forensic identification, particularly in scenarios where dental structures may be absent. This study aimed to develop and evaluate supervised machine learning models to predict chronological age based on mandibular morphometric measurements in children and adolescents. A sample of lateral cephalometric radiographs from 401 orthodontic patients aged between 6 and 16 years was analysed. Linear and angular mandibular measurements including the total mandibular length (Co-Pog), mandibular ramus height (Co-Go), mandibular body length (Go-Gn), and the gonial angle (Ar-Go-Me) were analysed. Eight supervised machine learning algorithms were trained to predict chronological age based on these measurements and sex. The dataset was split into training (80%) and test (20%) sets, with stratified 5-fold cross-validation to prevent overfitting. Model performance was evaluated using mean absolute error (MAE), mean squared error (MSE), root mean squared error (RMSE), and coefficient of determination (R²), with 95% confidence intervals estimated via bootstrapping. The models based on mandibular morphometric features and sex achieved a minimum MAE of 1.54 years (95% CI: 1.33–1.76) and RMSE of 1.93 (95% CI: 1.66–2.18) on the test set. Cross-validation confirmed model stability, with the Gradient Boosting Regressor achieving the best performance, showing a MAE of 1.21 (95% CI: 1.09–1.32) and R² of 0.56 (95% CI: 0.46–0.64). Total mandibular length (Co-Pog) and mandibular ramus height (Co-Go) were the most important predictors. Pairwise comparisons revealed statistically significant differences favoring ensemble methods over linear and simpler tree models. Supervised machine learning models demonstrated promising accuracy for age estimation based on mandibular measurements in growing individuals. Gradient Boosting emerged as the most effective algorithm. However, the generalizability of the models may be influenced by population-specific characteristics and the need for prior knowledge of certain predictor variables. Further external validations are recommended to enhance model applicability across diverse forensic contexts.

Early childhood caries (ECC) is a chronic, infectious disease that affects the primary dentition of young children. It is the result of an imbalance of risk factors and protective factors that influence the disease. The aim of this study was to assess genetic and environmental factors that may contribute to ECC. Two hundred and fifty-nine unrelated children were evaluated using a cross-sectional design. Data on oral habits were obtained through a questionnaire, and caries experience data were collected by clinical examination. Twenty-three markers in 10 genes were studied. Genotyping of the selected polymorphisms was carried out by real-time PCR. Regression analyses were performed comparing individuals with and without caries experience. Of 259 subjects, 123 were caries free. The genotype TT in ALOX15 (rs7217186) was a risk factor for ECC, whereas the genotypes GG in ENAM (rs1264848), AG and GG in KLK4 (rs198968), CT in LTF (rs4547741), and GG in TUFT1 (rs3790506) were protective for EEC. In conclusion, environmental factors and gene interactions can act as protective or risk factors for ECC. These factors together contribute to the presence and severity of the disease.

Human periodontal ligament (hPDL) fibroblasts play a major role during periodontitis and orthodontic tooth movement, mediating periodontal inflammation, osteoclastogenesis, and collagen synthesis. The highly COX-2-selective NSAID etoricoxib has a favorable systemic side effect profile and high analgesic efficacy, particularly for orthodontic pain. In this in vitro study, we investigated possible side effects of two clinically relevant etoricoxib concentrations on the expression pattern of mechanically strained hPDL fibroblasts and associated osteoclastogenesis in a model of simulated orthodontic compressive strain occurring during orthodontic tooth movement. hPDL fibroblasts were incubated for 72 h under physiological conditions with etoricoxib at 0 μM, 3.29 μM, and 5.49 μM, corresponding to clinically normal and subtoxic dosages, with and without mechanical strain by compression (2 g/cm2) for the final 48 h, simulating conditions during orthodontic tooth movement in compressive areas of the periodontal ligament. We then determined gene and/or protein expression of COX-2, IL-6, PG-E2, RANK-L, OPG, ALPL, VEGF-A, P4HA1, COL1A2, and FN1 via RT-qPCR, ELISA, and Western blot analyses as well as apoptosis, necrosis, cell viability, and cytotoxicity via FACS, MTT, and LDH assays. In addition, hPDL fibroblast-mediated osteoclastogenesis was assessed by TRAP staining in coculture with RAW267.4 cells for another 72 h. Gene and protein expression of all evaluated factors was significantly induced by the mechanical compressive strain applied. Etoricoxib at 3.29 μM and 5.49 μM significantly inhibited PG-E2 synthesis, but not COX-2 and IL-6 gene expression nor RANK-L-/OPG-mediated osteoclastogenesis or angiogenesis (VEGF-A). Extracellular matrix remodeling (COL1A2, FN1) and bone anabolism (ALPL), by contrast, were significantly stimulated particularly at 5.49 μM. In general, no adverse etoricoxib effects on hPDL fibroblasts regarding apoptosis, necrosis, cell viability, or cytotoxicity were detected. Clinically dosed etoricoxib, that is, a highly selective COX-2 inhibition, did not have substantial effects on hPDL fibroblast-mediated periodontal inflammation, extracellular matrix remodeling, RANK-L/OPG expression, and osteoclastogenesis during simulated orthodontic compressive strain.

Objective To perform a systematic review/meta-analysis to elucidate the scientific basis for the association between genetic variations and risk of external apical root resorption (EARR) in orthodontic patients. Materials and methods Four databases (PubMed, Web of Science, Scopus, LILACS) were electronically searched until November 22, 2020, followed by manual and gray literature search. Case-control or cross-sectional studies that evaluated genes involved in the susceptibility of orthodontic patients to EARR were eligible. Two reviewers applied the inclusion and exclusion criteria, extracted qualitative data, as well as assessed methodological quality using instrument proposed for genetic studies. For synthesis results, narrative and quantitative data (meta-analysis) were performed. The certainty of the evidence was tested using the GRADE Working Group approach. Results Of 201 articles in total, 16 studies were included in the review. Of these, 11 presented moderate and 5 of high methodological quality. In the narrative analysis, from 16 studies, 15 studies (10 genes) showed a significant association with EARR and 9 studies were included in the meta-analysis. Only the polymorphism rs208294 in P2RX7 (dominant model) was associated with EARR (OR = 0.52, 95%CI = 0.29–0.95, p  = 0.03) and presented a very low certainty of the evidence. Conclusion Narrative analyses of individual studies demonstrated an association of many genes. The number of studies for each genetic variation was very low, and methodological heterogeneity between the studies was observed. Quantitative analyses (meta-analysis) could only show an involvement for P2RX7 (rs208294) in the risk of orthodontic patients to EARR at a very low certainty of evidence. (CRD42018085411). Clinical relevance The knowledge regarding the molecular aspects involved in the etiology of EARR will allow orthodontists to use a personalized treatment and early diagnosis of risk patients. This systematic review demonstrates that more studies are necessary to unravel the role of genetic variation for patients’ risk to EARR during orthodontic tooth movement.

Introduction This study aimed to investigate if the mandibular trabecular bone structure of children and teenagers with cleft lip and/or cleft palate (CL/P) differs from non-cleft children using fractal analysis. Methods Children aged between 5 and 15 years with CL/P (cleft group) and a control group were recruited. Syndromic cases of CL/P and isolated cleft palate (CP) were excluded. To obtain the fractal dimension (FD) of the mandibular bone, regions of interest (ROI) were first delineated within the condyle and body of the mandible on panoramic radiographs. Subsequently, the FD was calculated using the box-counting algorithm on these defined ROIs. The results were adjusted by sex and age in a generalized linear model (GLM) with alpha error tolerance of 5%. Results A total of 205 patients were included. One hundred patients were allocated into the control group and 105 into the cleft group (37 CL and 68 CLP). The fractal dimension (FD) was statistically higher in the control group compared to the study group for both regions of interest (ROIs) ( p  < 0.001). In the GLMs, cleft was associated with low FD in the condyle (Beta=-0.132; p  < 0.001). In the body of the mandible, cleft was also associated with decreased FD values (Beta=-0.154; p  < 0.001). CLP presented decreased FD values in the condyle (Beta=-0.016; p  = 0.004). Conclusion Children with CL/P had lower FD values in the mandible compared to the control children, which may indicate that patients born with CL/P present a less complex bone structure.

Background This study aimed to develop machine learning-based predictive models for sex determination using the height and width of the mandibular symphysis from two-dimensional lateral cephalometric images. Data from 495 adult patients who underwent lateral cephalometric radiography at a private clinic in southern Brazil were analyzed. Mandibular symphysis measurements were collected and used to train eight supervised machine-learning algorithms. The models were optimized using Grid Search and evaluated through a 5-fold cross-validation. Metrics such as Area Under the Curve, precision, sensitivity, and F1-score were calculated, with confidence intervals estimated via bootstrapping. Results The analyses showed that both the height and width of the mandibular symphysis exhibited statistically significant differences between the sexes ( p  < 0.05). The models achieved Area Under the Curve values ranging from 0.77 [95% CI: 0.69–0.85] to 0.60 [95% CI: 0.46–0.62] in testing, and from 0.78 [95% CI: 0.76–0.82] to 0.68 [95% CI: 0.64–0.74] in the cross-validation. Among the evaluated algorithms, the SVM, Logistic Regression, and K-Nearest Neighbors models demonstrated the highest predictive performance. Conclusion Machine learning enabled sex determination based on mandibular symphysis measurements. The results suggest that this approach may serve as a complementary tool in forensic anthropology. Future studies should validate these models in different populations to ensure their generalizability. These findings suggest that the application of artificial intelligence methods can enhance the accuracy of sex determination, contributing to significant advancements in the field.

Objectives: Temporomandibular disorder (TMD) is considered a functional disorder with multifactorial aspects. The goal of this study was to investigate if genetic polymorphisms in the COL2A1 gene could be associated with TMD in adolescents. Study design: The case group (TMD-affected) included individuals diagnosed with any of the following TMD subgroups according to the RDC/TMD criteria: myofascial pain, disc displacements and arthralgia. Genomic DNA for molecular analysis was extracted from buccal cells and genetic polymorphisms in COL2A1 were genotyped by real time polymerase chain reactions using the TaqMan assay. Data were analyzed using the Epi Info 3.5.7 and Stata software. Results: 249 subjects were included in this study (148 subjects “affected” by TMD). There were no significant differences between the affected and unaffected individual (p>0.05), for TMD, arthralgia and myofascial pain however, rs2276454 was borderline in the genotype distribution (p=0.07) and was associated with disc displacement (p=0.03) in the allelic distribution. Recessive model showed significant differences between groups for with disc displacement (p=0.02). Conclusions: Genetic polymorphisms in COL2A1 are not associated with myofascial pain, arthralgia or TMD in adolescents but this study provides evidence that rs2276454 is involved in the disc displacement of the temporomandibular joint.

ObjectiveThis study aimed to evaluate the genotoxic effects in the oral epithelial cells of patients undergoing fixed orthodontic treatment and to compare these to a control group without treatment. The null hypothesis to be tested is that corrective orthodontic treatment at different periods does not cause genotoxic effects in patients.Material and methodsAn observational cross-sectional study including 74 patients enrolled in corrective orthodontic treatment and 21 control patients, between 11 and 35 years of age, of both genders, participated in the research. Patients undergoing treatment were divided into four treatment groups differentiated by treatment periods: G1, n = 21 (1 month to 12 months); G2, n = 21 (13 to 24 months); G3, n = 23 (25 to 48 months); and G4, n = 9 (over 48 months). Cells were collected by scraping the internal side of the cheek and subsequently placed in tubes containing 0.9% sodium chloride solution. The sample underwent evaluation for genotoxic effects by means of the micronucleus test (MNT). Bivariate analyses were performed using parametric tests (t test or ANOVA) and nonparametric tests (Chi-square test, Kruskal-Wallis test, Dunn post-test). The adopted level of significance was 5%.ResultsStatistically significant differences for any of the genotoxic abnormalities (binucleated, trinucleated, karyolysis, piknosis, nuclear buds) were not found except for karyolysis, which was higher in the control group than in G4 (p < 0.05).ConclusionsThis study did not demonstrate evidence of genotoxic effects even after long periods of corrective orthodontic treatment.Clinical relevanceThis study explores genotoxic effects in fixed orthodontic patients.

The identification of genetic risk factors for non-syndromic oral clefts is of great importance for better understanding the biological processes related to this heterogeneous and complex group of diseases. Herein we applied whole-exome sequencing to identify potential variants related to non-syndromic cleft palate only (NSCPO) in the multiethnic Brazilian population. Thirty NSCPO samples and 30 sex- and genetic ancestry-matched healthy controls were pooled (3 pools with 10 samples for each group) and subjected to whole-exome sequencing. After filtering, the functional affects, individually and through interactions, of the selected variants and genes were assessed by bioinformatic analyses. As a group, 399 variants in 216 genes related to palatogenesis/cleft palate, corresponding to 6.43%, were exclusively identified in the NSCPO pools. Among those genes are 99 associated with syndromes displaying cleft palate in their clinical spectrum and 92 previously related to cleft lip palate. The most significantly biological processes and pathways overrepresented in the NSCPO-identified genes were associated with the folic acid metabolism, highlighting the interaction between LDL receptor-related protein 6 ( LRP6 ) and 5-methyltetrahydrofolate-homocysteine methyltransferase ( MTR ) that interconnect two large networks. This study yields novel data on characterization of specific variants and complex processes and pathways related to NSCPO, including many variants in genes of the folate/homocysteine pathway, and confirms that variants in genes related to syndromic cleft palate and cleft lip-palate may cause NSCPO.