Forces acting on restorations

Biomechanics deals with the forces, their distribution within the orofacial complex and how the forces are altered by restorations. Biomechanics studies the response of the oral tissues and the restorative material to various stresses. The interplay of the forces is altered by the cusps of the teeth, the contour of the restoration especially the marginal ridges. The stomatognathic system may thus be viewed as a stress generating and stress bearing unit. The operative dentist must design restorations so that the clinical stresses generated are always below the fatigue limit of the restorative material. Qualitative analysis such as strain concentration points, uniform stress regions etc. can be identified quite readily. The advent of superior computer processing power has revolutionized stress analysis. Finite element modelling (FEM) has become the dominant technique, overshadowing many traditional techniques for stress analysis. A properly contoured restoration is not only important for the material to be retained in the cavity, but it also bears a direct effect on the periodontium.