Three-dimensional finite element analysis of mechanical stress in symphyseal fractured human mandible reduced with miniplates during mastication.
OBJECTIVE
In this study we tried to analyze the stress distribution in a symphyseal fractured human mandible reduced by 2 different methods--reduction with 1 miniplate or with 2 miniplates--by using finite element (FE) analysis, and then compared the results with an intact mandible.


METHODS
Three-dimensional FE models of an intact mandible and symphyseal fractured mandibles reduced by 2 fixation methods were developed to analyze mandibular stress distribution and bite forces under 2 basic loading conditions, namely, clenching in the intercuspal position and left unilateral molar clenching. Groups of parallel vectors were used to simulate 9 pairs of masticatory muscles involved in the 2 static biting tasks.


RESULTS
Stress distributions in reduced mandible with 1 or 2 miniplates were more or less different from that of the intact mandible. The maximum stress occurred at the biting point. Meanwhile, the subcondylar region was a stress-bearing area. During left unilateral molar clenching, bite forces obviously reduced after fracture. Bite force and the stress distribution pattern in the mandible reduced with 2 miniplates were closer to that in the intact mandible.


CONCLUSIONS
It is suggested that the effect of the miniplates in stabilizing the continuity-broken mandible influence the restorations of the stress distribution pattern and bite force. Two miniplates have a biomechanical advantage over 1 miniplate on these restorations.
Wang
Hang
H
State Key Laboratory of Oral Disease, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
Ji
Baohui
B
Jiang
Wentao
W
Liu
Lei
L
Zhang
Ping
P
Tang
Wei
W
Tian
Weidong
W
Fan
Yubo
Y
D000328:Adult; D001696:Biomechanical Phenomena; D001732:Bite Force; D001860:Bone Plates; D003198:Computer Simulation; D003799:Dental Stress Analysis; D020342:Finite Element Analysis; D005593:Fracture Fixation, Internal / Q000295:instrumentation; D006801:Humans; D021621:Imaging, Three-Dimensional; D016268:Internal Fixators; D008297:Male; D008334:Mandible / Q000502:physiology*; D008337:Mandibular Fractures / Q000628:therapy*; D008409:Mastication / Q000502:physiology*; D008953:Models, Anatomic; D013314:Stress, Mechanical