Effect of firing procedures and layering thickness of porcelain on internal adaptation of zirconia cantilever resin-bonded fixed dental prostheses

Abstract

This study evaluated the influence of firing procedures and layering thickness of porcelain on internal adaptation of maxillary anterior cantilever zirconia resin-bonded fixed dental prostheses (RBFDPs). Methods: The maxillary right central incisor on a model was prepared for a single-retainer zirconia RBFDP. A total of 36 frameworks of cantilever zirconia RBFDPs were classified into three groups (CB0.5, CB1.0, and CB2.0 groups) based on the thickness of the cut-back on the facial surface (0.5 mm, 1.0 mm, and 2.0 mm, respectively). Feldspathic porcelain was layered onto the facial surface of the zirconia RBFDP frameworks. Internal space widths between the abutment tooth and the framework were measured before and after porcelain firing by a replica technique. The internal space values before and after porcelain firings were compared using the paired t-test within the same group (α = 0.05). Differences in internal space values (distortion) between before and after porcelain firing were compared using one-way analysis of variance and Tukey multiple comparison tests. Results: For all framework designs, internal space values after porcelain firing were significantly higher than those before firing. Among all groups, the CB0.5 group showed the lowest internal distortion values for the whole measured area. The CB2.0 group showed higher distortion values than the CB1.0 group. Conclusions: Porcelain firing procedures negatively impacted the internal space in cantilever zirconia RBFDPs. In addition, the increased volume of layering porcelain had a negative effect on the internal distortion of maxillary anterior cantilever zirconia RBFDPs.

Marginal fit and retention force of zirconia resin-bonded fixed dental prostheses in the posterior region with different designs

“…Marginal fit was evaluated using the replica technique. 22 The bonding surfaces of the zirconia frameworks were filled with black silicone (BITE-CHECKER, GC Co.) and placed on the master model under finger pressure until setting. The frameworks were then removed, and white silicone (FIT-CHECKER, GC Co.) was placed onto the black silicone to prevent its deformation.…”

Influence of different convergence angles of abutment teeth and cement spaces on internal adaptation of anterior CAD-CAM fixed dental prostheses

“…A cement space replica technique was used to measure internal spaces between the restorations and abutment teeth [12]. A silicone-based fitting check material (Fit Checker Advanced, GC, Tokyo, Japan) was applied to the inner surface of each restoration, and then a customized jig and a compression gauge (Ohba Keiki, Tokyo, Japan) were used to mount each restoration on an abutment tooth with a static loading pressure of 5 N (Fig.…”