Comparison of polishing methods for monolithic all-ceramic crowns after occlusal adjustment: Appropriate use of new polishing materials.

This study examined the effectiveness of two newly released grinding materials in Japan on two types of zirconia with different yttria contents. Rotary cutting tools may be used for occlusal adjustment of single zirconia crowns. Grinding and polishing are then required. Simplified zirconia crowns with 3Y and 5Y yttria contents were manufactured and used as samples. After occlusal adjustment, the surface roughness and gloss of samples were measured at each stage using grinding and polishing materials. No significant differences were observed in surface roughness between 3Y and 5Y zirconia. The use of newly released grinding materials was effective for the surface treatment of zirconia. However, the surface roughness required to omit compound grinding was not achieved. Additionally, omitting either of the two grinding material processes increased variability in surface roughness after final grinding. Compound grinding is strongly recommended after occlusal adjustment of monolithic all-ceramic crowns following their installation.