Effects of impression material and implant angulation on the impression accuracy of external connection implants: An in vitro study

Abstract

A precise impression is mandatory to obtain passive fit in implant-supported prostheses. The aim of this study was to evaluate the effect of impression material and implant angulation on the impression accuracy of external-connection implants. Four customized epoxy resin master models, with twoimplant analogs placed parallel or with different degrees of divergence (10, 20 and 30 degrees), were fabricated with their corresponding passively fitted reference frameworks. Ten impressions were taken, for each model, with vinyl polysiloxane (VPS) and polyether (PE) using custom open tray impression technique. Impressions were poured with type IV dental stone and vertical discrepancies between the reference frameworks and the platforms of the implant replicas were evaluated, with a stereo video microscope, applying the one-screw test. The data were analyzed using two-way ANOVA, Sidak, and one-sample t-test at p ≤ 0.05. No significant differences were found between PE and VPS at various angulations (p > 0.05). However, all groups showed a significant difference (p < 0.05) when compared to their true values. Within the limitations of this study, impression material and implant angulation had no significant effect on impression accuracy of external connection implants.