Porcelain Application Effect on the Adaptation of Customized Procera Abutments

Objective: The purpose of this study was to investigate the effect of porcelain application on the implant-abutment gap in customized 3-unit partial fixed bridges obtained through the Procera system. Methods: Implant–to-abutment distances were evaluated in three different stages of the manufacturing process of the prosthetic restoration under the scanning electron microscope at 1000X. Three implants embedded in PMMA were used for specimen preparation simulating first premolar, second premolar and first molar. The manufacturing process was comprised of customized abutment milling, abutment soldering at the region corresponding to the connectors using ND:YAG laser, and porcelain sintering to the cervical level on the buccal surface only. Ten wax patterns representing the metal frame of the partial fixed units were sculpted and their surfaces were scanned by the Procera system individually. Ten abutments were milled for each element, resulting in 30 titanium elements and ten fixed partial units. Three reference marks were placed in the buccal and lingual surfaces of each implant resulting in 18 reference points. Results: One-way ANOVA at 95% confidence level revealed that there was a significant increase in the distances after porcelain application and these values were not significantly different for the buccal and lingual sides except for the second premolar. Also, the values for the buccal and lingual surfaces were not significantly different for each implant after the first and second stages of production. Conclusions: According to the results obtained, it was shown that the alteration in gap distances occurred uniformly during the first and second stages of the 3-unit partial bridge production and these numbers were not significantly different for each implant. A significant increase occurs after porcelain application for all implants where the second premolar presented different values between the buccal and lingual surfaces.