Three-dimensional Finite Element Stress Analysis Of The Temporomandibular Joint During Mandibular Osteodistraction

Distraction osteogenesis is a more mature technique in orthopedics. Since 1990s, it has gradually been developed in oral and maxillofacial surgery. So there are more discussions in unknown fields . Researches about temporomandibular joint focus on basic studies including histology and morphology. With the broad use of finite element method in stress analysis in stomatology , many native and foriegn scholars put up many studies on two-dimension or three-dimension stress distributions of the temporomandibular joint and mandible. But the research about stress distributions of the temporomandibular joint during mandibular osteodistraction is seldom. In this experiment, the character of stress distributions of the temporomandibular joint in the process of mandible DO was initially analysed by a finite element model (FEM) of TMJ model with mandible . Thus the speculation should be studied further and deeply in the future in order to make farther research and offer experimental basis in clinic. Method: ?ANSYS6.1 finite element software was adopted in the study to establish three-dimensional finite element model of mandible and TMJ. ?The four types of DO studied here were : mid-line osteodistraction, unilateral ramus osteodistraction, bilateral osteodistraction, unilateral angle of mandible osteodistraction.??The results indicated as the following:1 ? To establish a TMJ model including mandible by means of three-dimensional finite element methods. The stress values were increased by the loads increasing in the process of mandible DO. But the area distribution was invariable.The lateral stress was greater than it interior or mid.Compressive stress widely distributed in condyle posterior ram and articular disc posterior band. Tensile stress widely distributed in condyle anterior ram , anterior band and intermediate zone of articular disc.2? During mid-line osteodistraction or bilateral osteodistraction, the lateral stress was greater than it interior or mid on both sides of TMJ. The maximal compressive stress distributed in the posterior-lateral condylar cartilage.The maximal tensile stress distributed in the interior-anterior condylar cartilage.3 ?During unilateral ramus or angle of mandible osteodistraction, the stress values of the TMJ loading were much more higher than those of the TMJ on the other side. At the same time, the lateral stress was greater than that at interior or mid on the TMJ loading ,but the interior stress was greater than it lateral or mid of the TMJ on the other side. The maximal compressive stress distributed at the posterior-lateral condylar cartilage and the maximal tensile stress distributed at the anterior- lateral condylar cartilage of the TMJ loading. The maximal compressive stress distributed at the posterior- interior condylar cartilage and the maximal tensile stress distributed at the interior-anterior condylar cartilage of the TMJ on the other side.