Effect Of Two Impression Techniques And Two Impression Materials On The Passivity Of Fit Of Implant Supported Prosthesis.

Abstract

Reproducing the intraoral relationship of implants through impression procedures is the first step in achieving an accurate, passively fitting prosthesis. The critical aspect is to record the 3-dimensional orientation of the implant as it occurs intraorally, along with reproducing fine surface details. Therefore, improper recording of the fine details in impressions results in inaccurate cast that will affect superstructure fit resulting in mechanical and biologic consequences that disrupt the function of dental implants. The research presented in this study evaluatedeffect of two impression techniques and two impression materials on the passivity of fit of implant supported prosthesis. A model of cast acrylic sheets was constructed by laser cutting machine and 2 holes were drilled in the center of its top surface by a drilling machine for the insertion of 2 implants. The 2 implants were inserted in the 2 holes perpendicular to the top surface of the master model surface simulating the clinical situation of missing lower second premolar. Custom made trays were fabricated for each open and closed impression techniques to fit the master model from cast acrylic sheets. Impressions used were divided into two main groups according to the impression technique.The two main groups were: • Group (1): open tray impression technique. • Group (2): closed tray impression technique. Each group was further subdivided into two subgroups according to impression material used: • Subgroup (A): polyvinylsiloxane in medium consistency • Subgroup (B): polyether in medium consistency