Evaluation of Abrasive Wear Characteristics on Reused Rotary Cutting Diamond Instrument and Tungsten Carbide Burs - An In Vitro Study.

AIM: To compare the abrasive wear of reused rotary cutting diamond instruments and tungsten carbide burs used for tooth preparation, through a scanning electron microscope (SEM) based morphological evaluation. MATERIALS AND METHODS: Thirty teeth samples were divided into five groups, with four groups (Group A, B, C, D) prepared using diamond rotary cutting instruments from different manufacturers and one group (Group AC) prepared with tungsten carbide burs. It was further subdivided into a number of tooth preparations for porcelain-fused-metal restorations. The rotary cutting instruments were reused five times, and each time before reuse, they were evaluated for surface roughness under ×45 magnification SEM. The rotary instruments were evaluated along the length at 2 and 4 mm from the tip under ×45 magnification. The data on abrasive were recorded and statistically analysed with ANOVA One-way and Tukey Honest Significant Difference (HSD) mean differences. RESULTS: The mean abrasive wear varied with the height of the rotary cutting instrument, with values ranging from 0.85 to 1.26 mm at 2 mm height and 1.01 to 1.22 mm at 4 mm height. One-way ANOVA displayed statistically significant differences between groups at both heights of 2 mm (F (5,24) = 8.998, P = 0.001) and 4 mm (F (4,25) = 4.311, P = 0.01). Post hoc analysis expressed that most pairwise comparisons were not significant, except for certain differences involving group AC ( P > 0.05). CONCLUSION: The reused rotary cutting diamond instruments had decreased abrasive wear than tungsten carbide burs.