Marginal Fit and Retention Strength of Zirconia Crowns Cemented by Self-adhesive Resin Cements

Abstract

The absolute marginal gap (AMG) precementation and postcementation and the retention of zirconia crowns cemented to standardized molar preparations (4×10) by self-adhesive resin cements (SARCs) were evaluated. The following SARCs were used: RelyX U-200 (RXU200; 3M ESPE, Seefeld, Germany), SmartCem 2 (SC2; Dentsply, Milford, DE, USA), and G-Cem Automix (GCA; GC, Alsip, IL, USA). The control adhesive resin cement was Panavia 21 (PAN; Kuraray Dental Co Ltd, Osaka, Japan). Twenty measuring locations at a constant interval along the margins were marked, and the AMG was measured by an image analysis system connected to a stereomicroscope (20×). The cemented copings were aged 270 days at 100% humidity and 37°C and then underwent 10,000 thermal cycles, 5°C-55°C. After aging, the crowns were tested for retention, and the debonded surfaces were examined at 3× magnification. The mean marginal gaps precementation and postcementation were 34.8 ± 17.4 μm and 72.1 ± 31 μm, respectively, with no statistically significant differences between the cements. A significant difference ( p≤0.001) in retention between the cements was found. The highest values were obtained for SC2 and GCA (1385 Pa and 1229 Pa, respectively), but these presented no statistically significant differences. The lowest values were found for PAN and RXU200 (738 Pa and 489 Pa, respectively), but these showed no statistically significant differences. The predominant mode of failure in all of the groups was mixed, and no correlations were found between marginal gap and retention.

Current status on lithium disilicate and zirconia: a narrative review

“…To date, it is possible to state that marginal precision of zirconia restorations is better than internal fit (probably because of the shape/size of the CAD-CAM milling burs) and that, in any case, precision values are well within the range of clinical acceptability reported in the specifications of the American Dental Association (ADA). Marginal gap values have been reported between 0 and 75 mm for SCs [151,152] and 140 mm for FDPs, the latter showing an increasing proportional to framework span [119,120,127,153].…”

The Retentive Strength of Zirconium Oxide Crowns Cemented by Self-Adhesive Resin Cements before and after 6 Months of Aging

“…A long-term aging process (nine months water storage and 10,000 thermocycles) was also applied in our previous study conducted with an identical study design [6], but in contrast to the current study, it reported unsatisfactory retention strength values of the Lava Y-TZP crowns, which greatly differed between the SARCs. RelyX U-200 and Panavia yielded 0.49 and 0.74 MPa in the previous study, respectively [6], and 2.29 and 3.06 MPa in the current study, respectively. The difference lies in the surface treatment of the Y-TZP crowns: in the current study, we used combined mechanical (sandblasting by alumina particles) and chemical (Z-Prime™ Plus) surface treatments, while Pilo et al [6] did not use any surface treatment.…”

“…A drawback of this study was that all the samples went through thermocycling before the incubation period. In contrast, the retention strength of Lava Y-TZP crowns after severe aging conditions (nine months water storage and 10,000 thermocycles) yielded unsatisfactory values (<1.4 MPa) in SARCs cemented to prepared human molars [6]. The disadvantage of this study was that the intaglio surfaces of the Y-TZP crowns were not sandblasted and primed.…”

“…A minimum incubation period of six months for testing the bond strength durability of SARCs to zirconia is advocated, whereas shorter incubation periods might provide misleading results [20,21]. A long-term aging process (nine months water storage and 10,000 thermocycles) was also applied in our previous study conducted with an identical study design [6], but in contrast to the current study, it reported unsatisfactory retention strength values of the Lava Y-TZP crowns, which greatly differed between the SARCs. RelyX U-200 and Panavia yielded 0.49 and 0.74 MPa in the previous study, respectively [6], and 2.29 and 3.06 MPa in the current study, respectively.…”

Bioactive Glass Coated Zirconia for Dental Implants: a review

“…Zirconia with better optical, aesthetic, mechanical and biological qualifications, is a hopeful substitute to traditional Ti implant system for oral recovery [61][62][63][64], and is produced by the oxidation of zirconium [25,27,[65][66][67]. Zirconium, which is a transition metal [56,68] with greywhite color [69][70][71][72][73], can be used to make zirconia implant.…”