Effect of Sterilization (Autoclave) on Wear of Tungsten-Carbide Burs Coated With Diamond Particles With Different Thicknesses

Background: Extending the lifespan and improving the physical properties of dental burs as the most extensivly used instruments have been the subject of several studies. One of the proposed methods is using surface coatings for the burs. Since the dental instruments are reused, they require sterilization. One of the possible causes of the damage to dental burs is autoclaving process. This study aimed to investigate sterilization (autoclave) effect on wear of diamond coated tungsten-carbide burs with different thicknesses. Methods: In this in vitro study, 40 tungsten-carbide dental burs (IQ DENT, Poznan, Poland) were selected, out of which 20 burs were coated with 1.5-μm-like diamond particles, and 20 burs were coated with 3.5-μm by PVD method using Swin Plasma Coating Machine. Then, the burs were randomly divided into four groups (n=10) as follow: G1: 1.5 μm thickness coated burs without sterilization; G2: 3.5 μm thickness coated burs without sterilization; G3: 1.5 μm coated with sterilization; and G4: 3.5μm thickness coated burs with sterilization. Their weights were measured before wear test.Wear test was performed and then they were re-weighted. Data were analyzed using SPSS software (version 21) as well as Two-way ANOVA and Tukey HSD supplementary tests (α=0.05). Results: Mean and standard deviation of the burs weights without sterilization in the control groups were 7.31±2.63 and 7.96±1.61 mg, respectively; and mean and standard deviation of the burs weights in the sterilization groups were 7.06±0.98 and 7.12±1.11 mg, respectively. The study results showed that "sterilization application" and "thickness of coated layer" were the main factors and their intraction had no statistically significant difference (P=0.589). Conclusions: The sterilization process had no effect on wear of diamond coated tungsten-carbide burs with different thicknesses.