[Evaluation of the stress distribution in tooth implant-supported fixed partial prostheses on different bone types under dynamic loads].

OBJECTIVE: This study aims to evaluate the influence of different bone types on the stress distribution in tooth implant-supported fixed partial prostheses by using finite element (FE) analysis. METHODS: Four FE models of mandibular arch containing one implant splinted to the mandibular second premolar were built according to bone types I, II, III, and IV. Dynamic loads of 250 N were applied to the buccal and lingual cusps of the prostheses in different directions to simulate the masticatory cycle. The maximum Von Mises stresses were calculated using the FE analysis software. RESULTS: The maximum Von Mises stresses of the cortical bones were 89.229, 91.860, 125.840, and 158.420 MPa, increasing from type I to type IV, respectively. The maximum Von Mises stresses of the trabecular bone were 58.584, 43.645, 21.688, and 18.249 MPa, decreasing from type I to type IV, respectively. During the process of dynamic loading, the maximum Von Mises stresses of the cortical and trabecular bones followed the order buccal to tongue loading>tongue to buccal loading>vertical loading. CONCLUSION: The results showed that bone type significantly influenced the stress distribution in bones, and that for tooth implant-supported fixed partial prostheses, bone types I and II were a better choice than bone types III and IV. More caution should be exercised when restoring missing teeth using tooth implant-supported fixed partial prostheses in softer bone regions.