IADR Abstract Archives
Nanodiamond-Coated Milling Bits Enhance Glossiness of Zirconia After Sintering
Objectives: This study aims at compare the various effects of cutting dental zirconia with nanodiamond-coated or ordinary milling bits.
Methods: Four pieces of dental zirconia (WIELAND, Ø985mm, thickness:25mm) were used in this study. Two types of milling bits, one with nanodiamond-coating and one without, were used to cut the dental zirconia green blank in 3 different speeds (1000, 1500 and 2000 rpm) in a dental milling machine. The unsintered and sintered zirconia surfaces were evaluated with glossmeter, optical profilometer for surface roughness (Sa, Sz and Sq), SEM and EDX. SEM and EDX were also used to evaluate the milling bits. Three-way ANOVA was used to evaluate the effects (sintering, milling bit coating and milling speed) on these zirconia, and one-way ANOVA with Tukey post hoc test was used to evaluate statistical significance of glossiness and roughness at a=0.05.
Results: With respect to glossiness, three-way ANOVA revealed that sintering, milling speed and milling bit coating are significant factors (p<0.05). The glossiness of the sintered zirconia block was statistically higher than that of the unsintered block (p<0.05). For sintered zirconia, the nanodiamond-coated milling bit yielded a statistically (p<0.05) higher glossiness in all milling speeds than uncoated, save for using uncoated milling bit in 1500 rpm. However, in terms of roughness, only sintering showed to be a statistically significant factor (p<0.001) outweigh other two factors, and sintered zirconia always to have lower Sa, Sz and Sq than unsintered. Using EDX, it can be seen a higher Carbon elemental content on the zirconia surface with the coated bit in all speeds. From SEM, milling bits were found to wear out after use and coating has peeled off the surface after cutting the zirconia. EDX has verified that the Carbon is reduced from the milling bits surface.
Conclusions: Overall, the nanodiamond-coated milling bit can be operated in various speeds resulted in a higher gloss on the sintered zirconia block, while ordinary uncoated milling bit can only achieve the same glossiness at a designated speed. The type of milling bits and the speeds have no significant effect on the surface roughness.
Methods: Four pieces of dental zirconia (WIELAND, Ø985mm, thickness:25mm) were used in this study. Two types of milling bits, one with nanodiamond-coating and one without, were used to cut the dental zirconia green blank in 3 different speeds (1000, 1500 and 2000 rpm) in a dental milling machine. The unsintered and sintered zirconia surfaces were evaluated with glossmeter, optical profilometer for surface roughness (Sa, Sz and Sq), SEM and EDX. SEM and EDX were also used to evaluate the milling bits. Three-way ANOVA was used to evaluate the effects (sintering, milling bit coating and milling speed) on these zirconia, and one-way ANOVA with Tukey post hoc test was used to evaluate statistical significance of glossiness and roughness at a=0.05.
Results: With respect to glossiness, three-way ANOVA revealed that sintering, milling speed and milling bit coating are significant factors (p<0.05). The glossiness of the sintered zirconia block was statistically higher than that of the unsintered block (p<0.05). For sintered zirconia, the nanodiamond-coated milling bit yielded a statistically (p<0.05) higher glossiness in all milling speeds than uncoated, save for using uncoated milling bit in 1500 rpm. However, in terms of roughness, only sintering showed to be a statistically significant factor (p<0.001) outweigh other two factors, and sintered zirconia always to have lower Sa, Sz and Sq than unsintered. Using EDX, it can be seen a higher Carbon elemental content on the zirconia surface with the coated bit in all speeds. From SEM, milling bits were found to wear out after use and coating has peeled off the surface after cutting the zirconia. EDX has verified that the Carbon is reduced from the milling bits surface.
Conclusions: Overall, the nanodiamond-coated milling bit can be operated in various speeds resulted in a higher gloss on the sintered zirconia block, while ordinary uncoated milling bit can only achieve the same glossiness at a designated speed. The type of milling bits and the speeds have no significant effect on the surface roughness.