Worst Case Occlusal Stresses Experienced By Teeth and Restorations

Objectives: All-ceramic dental restorations are replacing metal and metal-supported dental restorations at a rapid pace. Ongoing development of all-ceramic materials has resulted in a very large number of products for clinicians to choose from. The selection is often based on material strength measured in vitro, which may not always predict the true performance characteristics of a material when used in vivo. The objective of this study is to provide data to aid the development of a clinically-validated model to aid clinicians to select an appropriate restorative material for a given scenario.

Methods: A novel strain gauge transducer was developed and purpose-built to record the maximum voluntary bite forces between individual opposing teeth. The transducer design allowed accurate recordings of bite forces between single opposing teeth. The bite forces of twenty male and twenty female participants were recorded and their teeth scanned using a 3Shape Trios scanner. The scan data was exported to the accompanying software to quantify the surface area of the contact points between opposing teeth.

Results: A large scatter of bite forces were recorded, consistent with other reports. Bite forces from as low as 83.9 Newton (N) to 1642.8 N, with a mean of 430.4 N (sd = 279.4) were recorded. However, the main aim of this work was to identify the highest possible forces generated by individuals, and numerous forces over 1000 N were recorded. Individual contact point areas as small as 0.3mm² were measured. Combining the bite force information with small contact areas provide insight to the high stresses restorations may be subjected to during function.

Conclusions: The contact point stress findings of this project help inform appropriate material selection and restoration design features for all-ceramic restorative materials. Furthermore, it provides new data for the development of a clinically-validated model to test all ceramic materials.
The contact point stress findings of this project help inform appropriate material selection and restoration design features for all-ceramic restorative materials. Furthermore, it provides new data for the development of a clinically-validated model to test all ceramic materials.