Effect of Diamond-like Carbon Coating Applied by the Physical Vapor Deposition Technique on Wear of Diamond and Tungsten Carbide Dental Burs

Abstract

Background: The methods of increasing the longevity of dental burs by improving the mechanical properties of these surfaces, can increase their longevity. This study assessed the effect of diamond-like carbon (DLC) coating applied by the physical vapor deposition (PVD) technique on wear of diamond and tungsten carbide (TC) burs. Methods: In this in vitro study, 30 diamond and 30 TC burs were evaluated in four groups, including TC burs without coating (control), TC burs with a 3.5-µm DLC coating applied by the PVD technique, diamond burs without coating (control), and diamond burs with a 3.5-µm DLC coating applied by the PVD technique. The burs were weighed by a digital scale, underwent the pin-on-disc wear test, and were weighed again. The weight loss indicated the degree of wear in each group. For qualitative assessments, the surface of the burs was inspected under a stereomicroscope at×4 and×10 magnifications before wear, halfway through the test, and after the test. Finally, the data were analyzed by two-way ANOVA (α=0.05). Results: The effect of DLC coating was significant on the wear of burs (P=0.032), but the effect of the type of bur and their interaction effect on wear were not significant (P=0.151). A significant difference existed in wear among the four groups (P < 0.001), and the wear of coated burs was significantly lower than that of non-coated burs (P=0.012). Stereomicroscopic assessments revealed some residual diamond particles, the impression of dislodged particles and the path of wear on the surface of diamond burs, and the path of wear on the surface of TC burs. Conclusions: Overall, the DLC coating of diamond and TC dental burs by the PVD technique could increase their wear resistance irrespective of the bur type.