Biophysical stress analysis of restored teeth: experimental strain measurement

The substantial amount of literature on biophysical stress analysis of restored teeth is reviewed. Principal methods of analysis include photoelastic analogs, measurement and finite element techniques. It is asserted that although much has been learned from these activities, there is no integrated methodology for analyzing the strength of restored teeth. Such a methodology is proposed, involving both experimental and modelling components which are mutually corroborating. The rest of the paper concentrates upon the experimental component of the methodology, which is based upon strain gauge measurements obtained within the context of a servohydraulics framework. Data are reported on the strain measured in a wide variety of cavity sizes, both unrestored and utilizing a range of materials and techniques in the restored complex. It is shown that intracoronal restorations which feature hard tissue bonding and cuspal coverage yield restorations with significant recovery of stiffness.