Marginal discrepancies of Ni/Cr crowns for a soft tissue-level, trans-mucosal implant system

Objective To examine the marginal fit of frameworks for implant‐supported single crowns built with or without the use of prefabricated plastic copings. Methods Sixty premolar sized metal crown frameworks for cemented implant restorations were prepared by two separate dental laboratories. Twenty were prepared with the use of original plastic copings for burn‐out (OPC), twenty without any prefabricated plastic coping (WPC), and finally twenty with modified plastic copings (MPC). Specimens were inspected at 100× magnification. Marginal discrepancies can emerge at the vertical level as marginal gaps (MG) or horizontal differences in the circumferential precision of the restorations (HEX). HEX and MG were recorded at 10 different points in each metal crown. The ANOVA test was performed to estimate if there were statistically significant differences between the two dental laboratories. ANOVA Test was also used between Groups OPC, WPC, and MPC to evaluate differences in the mean MG and HEX values. The Tukey's post hoc test was also performed to determine whether couples of data sets were different or not. Results No statistically significant differences regarding HEX and MG were found among the two dental laboratories. Significant differences were found among OPC, WPC, and MPC groups both for MG and HEX (P