The efficacy of universal ceramic polishing kit on the surface roughness of various ceramic types

Abstract

The objective of this vitro study was to determine the effect of polishing performance of a universal ceramic polishing kit on the surface roughness of various ceramics. The ceramic specimen size 5 x 7 x 4 mm of lithium disilicate glass ceramic (IPS e.max CAD, Ivoclar Vivadent, Liechtenstein), translucent zirconia (VITA YZ XT, VITA Zahnfabrik, Germany) and zirconia-reinforced lithium silicate (Celtra Duo, Dentsply Sirona, United States) (n=8) were fixed with clear resin in PVC block, 14 mm in diameter. The specimens were ground with fine diamond bur for 15 seconds to simulate clinical gross contouring.The two-step polishing process started with coarse polishing (EVE Diacera H2DCmf) for 60 seconds and followed by fine polishing (EVE Diacera H2DC) for 60 seconds. The surface roughness (Ra) of specimens were measured after grinding process and every 15 seconds of the polishing process. The Ra measurement was analyzed using a non-contact optical profilometer (Alicona infinitefocusSL, Graz, Austria) at 50X magnification for quantitative measurements. The area of measurement was perpendicular to the polished direction and 5 areas were measured in each specimen. SEM micrographs were used for qualitative measurements of the surface. The force in the polishing process was controlled to 1 N by a customed-made device. From one-way repeated measures ANOVA, the result showed that when compared with the grinding step, the Ra of all ceramic types was significantly lower after being polished by coarse polisher at 15 seconds. After all polishing process, VITA YZ XT exhibited the lowest Ra followed by Celtra Duo and IPS e.max CAD, respectively. From one-way ANOVA, the results of Δ Mean Ra showed that coarse and fine polishing bur was more effective in VITA YZ XT than Celtra Duo and IPS e.max CAD, respectively.