Lithium Disilicate Ceramics Pretreated With Ti: Sapphire fs, Er; Cr: YSGG, and Er: YAG Lasers: A Study on Mechanical Properties, Energy Dispersive Spectroscopy, Color Alterations, and Surface Topography

To assess the efficiency of Er; Cr: YSGG laser (ECL), Er: YAG laser (EYL), and the Ti: sapphire femtosecond laser (TsFL) in terms of color change (ΔE) measured by a spectrophotometer, surface topography observed through SEM, surface roughness (Ra), and bond strength of Lithium disilicate glass–ceramic (LDC) to resin cement. A total of 84 LDC disks were manufactured and assigned randomly into four groups. Group 1-HFA treated, Group 2 treated with TsFL, Group 3 with EYL, and Group 4 with ECL. Each disk was coated with a silane coupling agent. Surface profiling of the LDC disc was evaluated via SEM and Ra was measured using a profilometer. The ΔE values were determined using the CIE L*a*b* system. Adhesive luting cement was applied to 10 samples from each group, followed by thermocycling to simulate aging. Shear bond strength (SBS) was assessed, and failure modes were inspected following SBS. ANOVA and Tukey's post hoc test were used for the comparison of means and SD among groups. The highest ΔE was observed in the control HFA (4.23 ± 1.02) treated group. Whereas, Group 2 TsFL (2.22 ± 1.11) pretreated samples displayed the lowest ΔE. Ra and SBS analysis unveiled that the maximum score of Ra (1155.01 ± 1.43 μm) and SBS (10.28 ± 0.17 MPa) was observed in Group 2 TsFL. Group 4 (ECL) conditioned discs showed the lowest Ra (1015.41 ± 1.31 μm) and bond integrity (8.15 ± 0.16 MPa). The TsFL serves as an effective alternative to traditional surface preparation methods as it enhances the mechanical properties of LDC (SBS and Ra) with no susceptible change in ΔE.