[Biomechanical evaluation of zygomatic implant in unilateral maxillary defect restoration].

Purpose: To establish a standardized and modularized finite element model of a normal human skull to simulate the unilateral defect pattern of the maxilla and the stress distribution of craniofacial skeleton with repair subject to the bite force, and to make biomechanical evaluation and functional design of the unilateral maxillary reconstruction method using the microsurgery bone graft and zygomatic implant.

Methods: Based on CT scan and image process technology, a modularized geometrical and finite element model of the human skull was built to simulate unilateral defect pattern of the maxilla and design of the position, direction, length of the zygoma fixture, and the number of the conventional fixtures. Biomechanical properties of the design were evaluated using finite element analysis (FEA) method.

Results: The highest stress peaks concentrated at the neck of the zygomatic fixture on the zygoma, while the rest of the peri-implant bone appeared to bear lower stress. The zygomatic fixture played an important role in transmitting the occlusal force substituting the zygomatic process brace.

Conclusions: The transmission of the occlusal force and stress distribution of the peri-implant bone of this reconstruction protocol is satisfied. Reconstitutions of the buttresses system ensure a stable base for occlusion and stress, which is secure and feasible to optimal unilateral maxillary rehabilitation. Supported by Shanghai Leading Academic Discipline Project (Grant No.Y0203).