Influence of Dentoalveolar Ankylosis on the Biomechanical Response of a Single-rooted Tooth and Surrounding Alveolar Bone: A 3-dimensional Finite Element Analysis

Introduction: Dentoalveolar ankylosis necessarily accompanies the loss of periodontal ligament (PDL), which might alter the biomechanical response of the tooth. The purpose of this study was to investigate the influence of dentoalveolar ankylosis on a single-rooted tooth and the surrounding alveolar bone structures in the biomechanical standpoint. Methods: A basic model of an intact maxillary central incisor and the surrounding bone structures was chosen for the numeric analysis. From this basic model, 6 different models were further developed by combining 3 types of endodontic status (an intact model, a nonsurgically treated model, and a surgically treated model) and 2-types of periodontal attachment condition (models with or without PDL). For each condition, maximum von Mises stress (sigma max) in dentin and bone and maximum tooth displacement (Delta R max) were calculated. Results: In models with dentoalveolar ankylosis, stress was concentrated on the cervical dentin around the cementoenamel junction and the alveolar bone crest, whereas the stress was more evenly distributed along the entire length of the root in models with normal PDL. The models with dentoalveolar ankylosis showed higher stress values in dentin (44.72%-80.56% of a max increase) and bone (24.23%-80.68% of a max increase) and lower tooth displacement (59.22%-63.97% of Delta R max decrease) compared with the models with normal PDL. Conclusions: Dentoalveolar ankylosis exerts significant changes on the biomechanical response of a single rooted tooth and the surrounding bone structures. The dentoalveolar complex with ankylosis showed characteristic stress concentrations, increased stress values, and decreased tooth displacement compared with that with normal PDL.