Fit of electroformed porcelain-fused-to-metal crown on implant abutment]

This study compared the adaptation of a conventional and an electroformed porcelain-fused-to-metal crown. A master model was selected from an ITI implant with a solid abutment (height: 4 mm). Conventional cast metal frameworks of 0.7 mm thickness were prepared with a high noble metal alloy (Degudent U, Degussa) for porcelain fusing (n = 5). Electroformed frameworks of 0.2 mm thickness were determined using pure gold deposition on the abutment using the Auro-Galva-Crown system (AGC, Wieland) (n = 5). Subsequently, a porcelain (Super Porcelain AAA, Noritake) was fused to each framework. Internal gaps between the framework and its abutment were determined using the thickness of a silicone fit checking material. The gaps were measured both before and after porcelain fusing. The thicknesses of the silicone layer of the electroformed and the conventional porcelain-fused-to-metal crown were 34.6 and 38.5 microns at the margin, 33.2 and 39.6 microns at the internal slope, 22.0 and 33.0 microns at the axial, 58.6 and 65.1 microns at the occlusal, respectively. Three-way analysis of variance revealed that the mean gaps in the electroformed porcelain-fused-to-metal crown were significantly thinner than those in the conventional porcelain-fused-to-metal crown (p < 0.05). The electroformed porcelain-fused-to-metal crown showed better adaptability than the conventional porcelain-fused-to-metal crown regardless of porcelain fusing.