Evaluation of different stable internal fixation in unfavorable mandible fractures under finite element analysis.

INTRODUCTION: The mandibular angle fracture is the most common fracture between this type of injury in jaw bone and also is the type of fracture treatment that presents a larger number of complications, and a series different osteosynthesis types have been studied over the years by the world literature. The finite element method is a form of mathematical analysis, which is based on dividing a structure into a finite number of small areas. It has the ability tomathematically model structures, making it possible to apply forces anywhere. MATERIAL AND METHODS: For this study, a three-dimensional mandible with an unfavorable angle fracture was simulated. Five different types of fixations were evaluated: group 1, Champy technique with one 4-holes miniplate, 2.0 system; group 2, technique with two parallel 4-holes conventional miniplates, 2.0 system; group 3, technique with two parallel 4-holes locking miniplates, 2.0 system; group 4, technique with one reconstruction 6-holes plate, 2.8 system in base jaw; and group 5, technique with one reconstruction 6-holes plates, 2.8 system in jaw body + one parallel 4-holes conventional miniplate, 2.0 system. RESULTS: The results showed that strains are better distributed through the locking miniplate and screws system and presented less stress concentration when compared with the conventional ones. The Champy technique had the worst results about of all groups. The use of the locking system shows less stress compared to the non-locking system, and the presence of a reconstruction plate associated with a mini plate does not lead to increased stability compared with an isolated reconstruction plate.