Bruxing-type dental wear simulator for ranking of dental restorative materials

Abstract

An instrumented dental wear test simulator was developed to simulate jaw movement in the chewing process between two molar teeth. It simulated the natural impact with sliding masticatory action, known as bruxing (defined as the gnashing, grinding, or clenching of teeth) type of wear, in order to simulate a worst-case dental wear scenario. In vitro wear testing of dental restorative materials was performed. Impact and sliding wear were simulated on the machine, with water as the lubricant, on three metal alloys (Tytin, Valiant Ph.D., Galloy) and three composite resins (Silux Plus, Z100, P50). The impact force for each machine cycle was brought closer to the maximum natural masticatory forces by the use of a shock absorbing layer. To replicate the natural masticatory action, the specimens had a surface profile with the shape of a conical depression. Ranking of the materials' performance on the wear test simulator was seen to be consistent with published clinical ranking. Metal alloys showed greater wear resistance than composite resins. Among the different metal alloys, those with lower hardness and compressive strengths exhibited greater wear. Composite resins with large filler particles wore worse than those with small filler particles. Results were compared with previous work on impact with sliding on a flat surface without a cushioning layer. It was concluded that the magnitude of the impact force and the angle of approach during impact with sliding wear are important parameters in the in vitro wear ranking of dental restorative materials.

Fracture force of tooth–tooth‐ and implant–tooth‐supported all‐ceramic fixed partial dentures using titanium vs. customised zirconia implant abutments

“…When adding 30% for safety reasons, FPDs need to show fracture forces of 250-300 N in anterior and 450-500 N in posterior areas (Kotioth et al 1997;Hidaka et al 1999). In artificial oral environments (DeLong & Douglas 1991;Teoh et al 1998), materials in new or somewhat risky application modes can be tested before conducting cost-intensive and time-consuming clinical trials. They can simulate various clinical parameters such as moisture and thermal or mechanical loading.…”

Comparative wear ranking of dental restoratives with the BIOMAT wear simulator. Part II. An SEM evaluation

“…The stress applied through the cast chromium counterbody was higher than that found clinically (3·9-17·3 MPa) during mastication (Anderson, 1956) to allow for stresses generated during nocturnal parafunction which could be as high as 60% that of maximum clench when a person is awake (Clarke, Townsend & Carey, 1984). As the ranking of materials' performance on the wear simulator was consistent with published clinical ranking (Teoh et al, 1998), this simulator model was used to study the quantitative wear of posterior restoratives (Yap et al, 1999). Emphasis was placed on the restoratives as our primary objective and not the counterbody although cast chromium alloys have been shown to be abraded by some composites (Willems et al, 1992).…”

“…In addition, fundamental in vitro wear tests are important for the study of the wear mechanisms, provision of data during material development and screening of materials prior to clinical trials. One of the latest in vitro wear tests developed for the study of wear mechanisms is the BIOMAT wear simulator (Teoh et al, 1998). This wear simulator was designed and made to duplicate as closely as possible the intra-oral movement of molar teeth during chewing.…”

Hardness and in vitro wear of a novel ceramic restorative cement

“…T eoh et al . (5) showed that small changes in the construction of a specific wear machine can significantly influence the ranking order of resin composites and amalgam. This illustrates the difficulties of in vitro wear tests to accurately simulate the oral conditions, and the need to better understand wear mechanisms occurring in the mouth.…”

“…To study clinical wear is time‐consuming and expensive. In vitro tests provide an accelerated screening of the clinical wear at relatively low cost under controlled, reproducible conditions (1–7). Ceramic materials have often been criticised for being too hard and causing abrasion of opposing teeth and restorations.…”