Contact Stress Distribution after Unilateral Condylar Fracture with Angulation of the Fractured Part: A Finite Element Model Study.

After a fracture of the condyle, the head of the condyle is often pulled inwards, which causes the fractured part to angulate medially. This change can cause a disbalance in the masticatory system. The disbalance could lead to contact stress differences within the temporomandibular joints (TMJs) which might induce remodelling within the TMJ to restore the balance. The contact stress in the fractured condyle during open and closing movements is expected to decrease, while the contact stress in the non-fractured condyle will increase. In a clinical situation this is hard to investigate. Therefore, a finite element model (FEM) was used. In the FEM a fractured right condyle with an angulation was induced, which was placed at different degrees, varying from 5° to 50° in steps of 5°. This study shows only minor differences in amount of contact stress between the fractured and the non-fractured condyle. The amount of contact stress in the condyles does not increase with a higher degree of angulation. However, with larger angulations, the contact stress within the fractured condyle is more centralized. Clinically, this more centralized area could be associated with complaints, such as pain. In conclusion, due to the more centralized contact stress in the fractured condyle, one would expect some minor remodelling on the fractured side with more angulation.