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Background: The maxillary central incisor is one of the most important anatomical indicators in esthetics, and stress distribution may vary among its five anatomical views (labial, palatal, mesial, distal, and incisal).Objective: To compare stress distribution among the five anatomical views of the maxillary central incisor under loading force at five angles and to observe and analyze the stress distribution in the dentin and periodontal ligament.Methods: We established three-dimensional finite element models of the five different views, which simulated the bite force with a static load force at 0∘, 30∘, 45∘, 60∘, and 90∘. The stress and displacement values for the cementoenamel junction (CEJ)-apical labial, palatal, mesial, and distal and the equivalent stress values on the periodontal ligament of the maxillary central incisor were calculated.Results: As the angle increased, the equivalent stress on the periodontal ligament, overall tooth displacement, equivalent stress, and displacement over the four views increased. The peaks of equivalent stress over the four views appeared within 0.8-17 mm below the CEJ, although all equivalent stress values decreased while approaching the peak. Within 1-19 mm below the CEJ, the equivalent stress over the M1 and P1 views of the maxillary central incisor decreased substantially.Conclusion: The peaks of the equivalent stress over the M1 and P1 views of the maxillary central incisor and their stress distribution were lower than those of the other three types. Our findings provided theoretical data on the biomechanics of this esthetically important tooth, which may be useful during implantation of missing maxillary central incisors. [ABSTRACT FROM AUTHOR]

Objective: To discover novel ectodysplasin-A (EDA) and wingless-type MMTV integration site family, member 10A (WNT10A) mutations in tooth agenesis (TA) patients., Study Design: Case series., Place and Duration of Study: Guanghua School of Stomatology, Guangzhou, China, from March 2018 to August 2020., Methodology: EDA and WNT10A were analysed in eleven TA families by PCR and Sanger sequencing. Bioinformatics and structure modelling analyses were performed after identifying different variants, to predict the resulting conformational alterations in WNT10A and EDA., Results:  Two novel mutations (c.796C>A (p.L266I), c.769G>A (p.G257R)) in EDA and two reported mutations (c.637G>A (p.G213S), c.511C>T (p.R171C))in WNT 10A were detected. Combined with the 3D structural analysis, we discovered a correlation between alterations in hydrogen bond formation and the observed phenotypes, potentially affecting protein binding., Conclusions: The mutations were predicted to be pathogenic through bioinformatics analyses. In addition, by identifying novel mutations, our knowledge regarding the TA spectrum and tooth development was considerably expanded., Key Words:  Anodontia, EDA, WNT 10A, Whole exome sequencing, Odontogenesis.