No abstract

A three-dimensional, static mathematical calculation of the stomatognathic system was done to predict total temporomandibular joint (TMJ) loading at different levels of jaw opening. The model assumed that muscle forces acting on the mandible could be simulated by a combination of contractile components (CCs) and elastic components (ECs) and that static equilibrium existed within the body of the mandible. The model also imposed the constraint that any generated joint reaction force would act on the centre of the condyle. The results of the model demonstrated that under all conditions of opening and for all values of the elastic modulus selected, the forces between the TMJ condyle and the articular eminence were compressive in nature. The compressive force magnitude increased from 2.7 to 27.6 N incrementally as the jaw opened from 10 to 40 mm. Overall data in this study indicated that the TMJ tissues undergo low levels of compression at open positions up to 40 mm. Finally, the condition of trismus (increased jaw closing activation with opening) was simulated, the joint reaction force at 20 mm opening increased from 7.7 to 64.9 N with only a 20% activation of the closers.

A three-dimensional, static mathemativalues of the elastic modulus selected, the forces between the TMJ condyle and the articular emical calculation of the stomatognathic system was nence were compressive in nature. The compressive done to predict total temporomandibular joint (TMJ) loading at different levels of jaw opening.force magnitude increased from 2·7 to 27·6 N increThe model assumed that muscle forces acting on mentally as the jaw opened from 10 to 40 mm. the mandible could be simulated by a combination Overall data in this study indicated that the TMJ of contractile components (CCs) and elastic compotissues undergo low levels of compression at open positions up to 40 mm. Finally, the condition of nents (ECs) and that static equilibrium existed trismus (increased jaw closing activation with within the body of the mandible. The model also imposed the constraint that any generated joint opening) was simulated, the joint reaction force at reaction force would act on the centre of the 20 mm opening increased from 7·7 to 64·9 N with only a 20% activation of the closers. condyle. The results of the model demonstrated that under all conditions of opening and for all

Changes of interarticular-space distribution during jaw opening were quantified with corrected sagittal TMJ tomograms using a computer-aided image analysing system.