The biomechanical-biological interface and its significance in oral disease

Biomechanics in the masticatory system are important determinants of muscle and articular function, forces and displacements in the dentition, and stresses and strains in the maxilla, mandible and cranium. They affect tissue responses in these sites, and play an important role in differentiation and growth. Of the various direct methods used to study structural and functional interactions, the most common are recordings of muscle activity, jaw and regional tooth displacements, tooth forces, and surface bone strains. Indirect experimental methods include bench-testing tissues to establish their material properties, and biomedical imaging to reconstruct the major anatomical components of the system. Together, such studies provide essential data for computer modelling by rigid-body dynamics or finite element analysis (FEA). The models permit estimation of parameters that are difficult to measure directly in living subjects, including viscoelastic behaviour in the muscles, articular discs and periodontal tissues, sutural strains, and regional bone stresses and deformations. Modelling has uses other than mimicry, and it has been employed extensively in implant-related research. There are now encouraging signs it is being used with increasing sophistication in the articular, maxillary, and craniofacial regions. More emphasis on structural and functional correlates related to pathology is likely in the future. The present review provides a foundation for further discussion of the topic.