[Analysis of stress in the periodontal tissue of the maxillary first molar on distal movement by finite element method].

OBJECTIVE: The aim of this study was to analyse the stress distribution in the periodontium of the maxillary first molar and to search optimal loads pattern when distal movement to provide biomechanical basis for the clinical practice. METHODS: By spiral CT scanning, a three-dimensional finite element model of the maxillary first molar was established, and then four different load patterns were added to the molar to obtain the optimal load partern for molar bodily distal movement. RESULTS: Different loads lead to different stress distributions when distal movement. CONCLUSION: A distalizing force combined with a countertipping moment (Mt/F = 10) and a counterrotation moment(Mr/F = 6) can lead to a lower and uniform stress on the distal side of the periodontal ligament, it implys a tendency of translation of the maxillary first molar.