Zirconia-Reinforced Lithium Silicate Marginal Gap Evaluation Using Various Self-Adhesive Resin Cements by SEM

Abstract

Background: This study aimed to evaluate the impact of three different self-adhesive resin cements on the marginal gap of full monolithic zirconia-reinforced lithium silicate (ZLS) single crowns. Methods: We divided forty-five typodont teeth, fully prepared for full monolithic crowns, into three groups (fifteen each) for the use of three different self-adhesive resin cements. We created a fourth control group (Temp-bond) by taking five teeth from each group before cementation with self-adhesive resin cements. All forty-five abutments were scanned using Primescan (an intra-oral scanner (IOS)), followed by digital design and grinding of zirconia-reinforced lithium silicate (ZLS) crowns with a four-axis machine. We first cemented the crowns of the control group (Temp-bond) and evaluated the marginal gap using a scanning electronic microscope (SEM). After removing the crowns from the abutments, we cemented the crowns for each group using a different self-adhesive resin cement and observed them under the SEM to evaluate the marginal gap. We used a Kolmogorov-Smirnov test, which found no normal distribution in the study variables (p < 0.05), followed by Mann-Whitney tests (α = .05). Results: The total mean marginal gap of the control group (24.67 ± 4.43 µm) was significantly lower compared to the self-adhesive resin cements groups (p < 0.0005). The total mean marginal gap of the G-cem ONE group (50.48 ± 6.38 µm) was significantly lower compared to the TheraCem group (p < 0.026) and RelyX U200 group (P < 0.008). The total mean marginal gap of the TheraCem group (66.28 ± 7.23 µm) was significantly higher than the G-cem ONE group (p < 0.026) but showed no significant difference with the RelyX U200 group (70.07 ± 10.12 µm, p > 0.110). Conclusions: All four groups showed a clinically acceptable marginal gap (< 120 microns). Although all three groups of self-adhesive resin cements demonstrated a significant increase in the marginal gap compared to Temp-bond group, they were within the limits of clinical acceptability. Regarding the marginal gap, in everyday dentistry it is recommended to use G-cem ONE self-adhesive resin cement for ZLS single crowns.