The effectiveness of polishing kits: influence on surface roughness of zirconia

This study investigated the effectiveness of intraoral and technical polishing kits. Zirconia specimens were sintered, ground, and polished with 14 different two-step or three-step polishing kits. Surface roughness (Ra, Rz) after each treatment step was determined, and scanning electron micrographs were made. Except for one system, all polishing kits were effective in reducing the surface roughness of ground zirconia. Differences in surface roughness were high after the first polishing step but were reduced to Ra/Rz values similar to or lower than those of the sintered reference after the final polishing step. Achieving smooth surfaces depended on a sequential application of all polishing steps.