Influence of various gypsum materials on precision of fit of CAD/CAM-fabricated zirconia copings

The clinical applicability of CAD/CAM-fabricated zirconia copings is tested using working models made from four different high-strength Type IV gypsum materials. Each of the four materials was used to fabricate 15 zirconia copings. Precision of fit was measured with a digital electron microscope using the silicone replica technique. The mean and standard deviation of each reference point were analyzed using the one-way analysis of the variance (ANOVA) and Tukey's honest significant difference (HSD) tests (alpha=0.05). The overall marginal and internal fits of the zirconia copings were as follows: GS (GS: Grey Stone) group: 91.43 mu m, LS (LS: Light green Stone) Group: 87.89 mu m, RS (RS: Red Stone) Group: 88.75 mu m, BS (BS: Beige Stone) Group: 82.78 mu m. There were no significant differences between the mean adaptations of the gypsum varieties (p>0.05). This confirmed that the type of gypsum material used does not determine the precision of fit of a prosthesis.