Evaluation of the marginal fit in fixed prosthodontics

Abstract

The marginal gap space is frequently responsible for prosthodontic restoration loss, due to specific demineralization process by micro-leakage and bacteria colonization. The aim of the in-vitro study was to evaluate the width of the marginal gap in porcelain fused to metal (PFM) crowns. A light-body silicone was used to measure the marginal gap between the abutment tooth and crown in order to evaluate absolute discrepancy with the replica technique (RT). Twenty PFM crowns were fabricated on premolar die marginal discrepancies ranging from 61.5 to 75.0 microns, mean vertical discrepancies ranging from 22.9 -46.0 micron and mean horizontal discrepancies ranging from 42.0 to 58.8 micron. Based on selection of 100 microns as limit of clinical acceptability, restoration margins were presented with minimal risk for caries occurrence, and the prostheses demonstrated acceptable marginal adaptation.