An Experimental Analysis of Interproximal Tooth Wear as a Baseline for Studying Long-Term Masticatory Function

Objectives: While there is a predictable relationship between masticatory function and craniofacial form, little is known regarding the long-term interaction between jaw function and craniofacial growth. Given that interproximal tooth wear is influenced by long-term masticatory function, the interproximal wear facet area, measured in vivo in patients, could serve as a long-term functional proxy. Our goal is to assess the relationship between function and interproximal wear using an in vitro model. We examined a), variability in interproximal wear in teeth under identical wear conditions, and b), whether wear facet area is a reliable proxy for volume of enamel loss.
Methods: We selected a sample of n=10 impacted third molars, sectioned and embedded in silicon with interproximal surfaces exposed. Teeth were mounted on a custom tooth-wear machine with mesial surface mounted opposing its distal surface. Samples were subjected to 650,000 cycles with an applied weight of 5.0 lbs. Positive replicas of impressions were scanned using a 3M optical scanner and analyzed to measure wear facet area and volumetric changes using AnSur software.
Results: There was average volume loss of 0.054 mm³ and average wear facet area of 1.71 mm². Variation was high in both variables with 176% difference between maximum and minimum volume loss values and 138% difference between maximum and minimum wear facet area values. There was non-linear relationship between wear facet volume and area. Wear facet area predicts volume loss up to approximately 0.090mm³ beyond which the curvilinear relationship becomes asymptotic.
Conclusions: Our results indicate a) that experimentally produced interproximal wear is highly variable and b) there is a limited predictable relationship between wear facet area and volume loss. This suggests that other factors (e.g., enamel properties) affect wear magnitude and may limit the ability to predict function from in vivo interproximal wear on narrow levels of functional variation.