THE INFLUENCE OF FINISH LINE CURVATURE ON THE MARGINAL GAP WIDTH OF CERAMIC COPINGS

Statement of problem. As a result of natural tooth anatomy or gingival recession, anterior teeth are more likely to present increased abutment finish line curvature. Purpose. The purpose of this study was to investigate the influence of the curvature of the finish line on the marginal gap widths of ceramic copings. Material and methods. An ivorine maxillary central incisor was prepared for 3 different abutment finish line curvatures (1, 3, and 5 mm). Thirty-six copings were fabricated for each of these curvatures by using Cercon, IPS e.max, and Lava systems. The marginal gap width was measured by using a stereomicroscope, and the data were subsequently analyzed by means of a 2-way ANOVA and a 1-way ANOVA (alpha=.05). Results. A significantly higher mean marginal gap width was found for the 5-mm curvature group (Cercon, 76.59 +/- 23.01 mu m; IPS e.max, 106.44 +/- 18.48 mu m; Lava, 128.34 +/- 20.79 mu m) than for both the 3-mm curvature group (Cercon, 60.18 +/- 9.74 mu m; IPS e.max, 81.79 +/- 16.20 mu m; Lava, 99.19 +/- 15.32 mu m) and the 1-mm curvature group (Cercon, 38.3 +/- 6.85 rho m; IPS e.max, 52.22 +/- 10.66 mu m; Lava, 69.99 +/- 6.77 mu m). Conclusions. The greater the finish line curvature, the wider the marginal gap widths for the 3 ceramic systems.