Effect of Finish Line on Marginal Fit of Sintered Gold Copings

Abstract

The aim of this study was to evaluate the vertical marginal gap of sintered gold copings and metal-ceramic crowns with different finish line preparations: a beveled round shoulder (BRS) and a beveled long chamfer (BLC), testing the null hypotheses that there are no differences in marginal gap regardless of finish line and phase of restoration (coping or crown). Stainless steel master models were fabricated to simulate tooth preparation for metal-ceramic crowns with different finish lines (BRS and BLC). Ten dies were obtained from each model. Preparations were coated with 2 layers of spacer to 1 mm from the margin. Sintercast gold copings were prepared, sintered and adjusted to the dies. The copings (n=10) were placed onto the master model and the marginal gap was measured in 24 equidistant points using optical microscopy (X230). An opaque and two body ceramic layers were subsequently applied to the copings and the same measuring procedure was performed for the crowns. The data were analyzed statistically using paired and unpaired Student's t-test (α=0.05). Mean marginal gap values (μm) for the copings and crowns were, respectively: 113.6 and 117.1 for the BRS; and 58.2 and 74.3 for the BLC preparation. Significantly greater marginal gaps (p=0.0307) were found for restorations with BRS than with BLC finish line, which also showed statistically significant differences in the gap size between coping and crown (p=0.001). In conclusion, marginal gap is influenced by ceramic application on copings fabricated on BLC preparation, and greater marginal gaps were found for restorations with BRS finish line, rejecting the experimental null hypotheses.

Effect of Anti‐Rotational Abutment Features and Novel Computerized Fabrication Techniques on the Marginal Fit of Implant‐Supported Metal Copings

“…Several factors may influence the marginal fit: 3 Ceramic material; 4 antirotation abutment features; 5 finish line curvature; 6 finish line preparation; 7 ceramic firing; 8 occlusal surface preparation; 9 cementation process; 10 cement type; 11 preparation angle; 12 the type of alloy, 8 and the fabrication method of the coping 13 . For cement‐retained implant‐supported single crowns, prefabricated standard titanium abutments with reduced diameter, increased taper, and narrow margins have been used widely.…”

Avaliação da adaptação marginal e rugosidade de superfície de <i>copings</i> confeccionados de Níquel-Cromo e Cobalto-Cromo injetados em moldes de revestimento a temperatura reduzida

“…O aumento das fendas marginais promove a descontinuidade da junção entre a parte cervical da prótese e o preparo, expondo o agente de cimentação aos fluidos do meio oral e gerando maior predisposição de acúmulo de biofilme. O resultado deste acúmulo é a microinfiltração e a irritação dos tecidos periodontais e pulpares, levando a um comprometimento da longevidade da restauração protética (10,11) . O desajuste marginal das restaurações fixas pode estar relacionado a eventuais erros no procedimento clínico e/ou laboratorial, além das características peculiares de cada liga.…”