Polishability of newly developed CAD-CAM blocks

Objectives: The main purpose of this study is to evaluate polished surface of 2 nano-ceramic blocks using a contact profilometer and a gloss meter using 2 different polishing methods.
Methods: Two nano-ceramic materials were prepared as disk specimens surface face roughness and gloss measurement. The control groups were consisted of resin nano ceramic (RNC) and experimental group were consist of flexible nano ceramic (FNC). Specimens of each group were polished with oxyalkylene polymer containing diamond powder (diamond paste) with a soft bristle brush for 10 seconds. When polishing, one group was polished with the same paste from beginning to the end (1-step). Another group was polished with changing the paste once during the same amount of polishing time (2-step). As a result, 2 different materials and 2 different polishing methods required 4 groups (n=10) and a total of 40 samples were prepared. After preparation of specimens, the surface roughness and gloss were measured using a contact profilometer and a gloss meter. One-way ANOVA followed by Tukey’s honestly significant difference (HSD) test (α =0.05) was used to statistically analyze the results.
Results: The testing results indicated that after 10-second polishing with diamond paste, all groups showed significant improvement in gloss and surface roughness. There were no significant differences in gloss and surface roughness between 2 different CAD-CAM blocks or 2 different polishing methods.
Conclusions: Single-step diamond paste polishing provides significant improvement in both gloss and surface roughness of 2 different nano ceramic materials in a short time. Addition of the paste during polishing did not affect the surface properties in this study.