Finite Element Evaluation of Different Osteosynthesis Variations That Used After Segmental Mandibular Resection.

PURPOSE: The purpose of this study was to evaluate the effect of different reconstruction plates and screw combinations on stress distribution of segmental resected mandibles using finite element analysis.

METHODS: Lateral (L) and lateral-central (LC) defects were simulated by a computer aided design modeling. The straight (s) and angular (a) titanium locking reconstruction plates of 2.5 mm (12 holes for L defects and 16 holes for LC defects) were modeled. Each screw was 2.5 mm in diameter and 10 mm in length. A total of 20 different screw placement combinations were created. The bite force used in the present model was a unilateral molar clench. The data obtained from finite element analysis were recorded as von Mises, maximum principle and minimum principle stress values.

RESULTS: It was observed that stress values on neck of screw were higher for screws close to the resection area. When the first screw was loosened, the stress on the plate body and the remaining screws increased. Principle stress values were within the tolerance limits of the bone.

CONCLUSION: The highest stress is observed in the screws nearest to the resection edge. Therefore, it is very important to place a screw adjacent to the resection edge.