Effect of different surface treatments and multimode adhesive application on the Weibull characteristics, wettability, surface topography and adhesion to CAD/CAM lithium disilicate ceramic.

Karina Barbosa Souza,Dayanne Monielle Duarte Moura,Mutlu Özcan,Rafael De Almeida Spinelli Pinto,Gabriela Monteiro De Araújo,Rodrigo Othávio De Assunção E Souza,Sarah Emille Gomes Da Silva,Fabíola Pessôa Pereira Leite

doi:10.1590/1678-7757-2020-0122

Abstract

This paper aims to evaluate the effect of different surface treatments on surface topography, wettability, and shear bond strength of resin cement to glass ceramic.Methodology:For SBS test, 32 blocks (7x7x2 mm) of lithium disilicate were obtained and randomly divided into eight groups (four blocks per group) according to each surface treatment (HF 20 s, 60 s, 120 s + silanization/S or Scotch Bond Universal/ SBU) and the Monobond Etch & Prime - MEP application followed or not by SBU. On each treated surface ceramic block, up to four dual-curing resin cement cylinders were prepared and light-cured for 40s (N=120/n=15). The specimens were thermocycled (10,000 cycles, 5-55°C, 30 s) and the SBS test (50KgF, 0.5 mm/min) was performed. Furthermore, failure analysis, wettability, AFM, and SEM were carried out. SBS data (MPa) were analyzed using Student's t-test, two-way ANOVA, Tukey's test (5%) and Weibull's analysis.Results:For HF experimental groups, two-way ANOVA presented the factors “etching time” and “bonding agent” as significant (p<0.05). After silane application, the HF groups presented similar bond strength. SBU application compromised the SBS, except for 120s etching time (HF120sS: 23.39ᵃ±6.48 MPa; HF120sSBU: 18.76ᵃ±8.81MPa). For MEP groups, SBU application did not significantly affect the results (p=0.41). The MEP group presented the highest Weibull modulus (4.08A) and they were statistically different exclusively from the HF20sSBU (0.58B).Conclusion:The HF 20s, 60s, 120 s followed by silane, promoted similar resin-bond strength to ceramic and the SBU application after HF or MEP did not increase the SBS.

Highlights

Concerning dislodgement, the bond strength and clinical performance of conventional lithium disilicate-reinforced glass ceramics can be affected by adhesive procedures and surface treatment
This study objective was to evaluate the effect of different hydrofluoric acid (HF) etching strategies (HF 20s, 60s, 120s + silanization or SBU) and the Monobond Etch & Prime (MEP) with and without application of SBU on the surface topography, wettability, and shear bond strength of resin cement to lithium disilicate glass ceramic
The application of HF followed by silanization is the most used method for increasing the restoration wettability and improving adhesion to the resin cement

Summary

Introduction

Lithium disilicate glass ceramics are among the most reliable restorative materials for indirect restorations, both for aesthetic and functional purposes, due to their biocompatibility, favorable appearance, and mechanical properties. Studies have reported excellent performance for anterior and posterior crowns (100% in a five-year follow-up and 94.8% after eight years), onlays and inlays (98.9% after five years and 89.6% after 12 years, respectively), and laminate veneers (82% to 96% after 10 to 21 years). In this context, Rosetta SM lithium disilicate ceramic (Hass, Gangneung, Korea) has been introduced, which, according to the manufacturer, presents high translucency, opalescence, and resistance due to its microcrystal structure, providing greater performance and simplified fabrication technique using computeraided design/computer-aided manufacturing (CAD/ CAM).7Despite the excellent longevity of glass ceramics, issues such as caries at crown margin, cervical faults, fractures, and restoration dislodgement were reported. Concerning dislodgement, the bond strength and clinical performance of conventional lithium disilicate-reinforced glass ceramics can be affected by adhesive procedures and surface treatment. The use of hydrofluoric acid (HF) followed by silanization (S) is the most commonly used surface treatment for the cementation of glass ceramics. the action of HF can promote regions of stress concentration in the ceramic and surface porosity, which can induce fractures. Studies have reported excellent performance for anterior and posterior crowns (100% in a five-year follow-up and 94.8% after eight years), onlays and inlays (98.9% after five years and 89.6% after 12 years, respectively), and laminate veneers (82% to 96% after 10 to 21 years).. Studies have reported excellent performance for anterior and posterior crowns (100% in a five-year follow-up and 94.8% after eight years), onlays and inlays (98.9% after five years and 89.6% after 12 years, respectively), and laminate veneers (82% to 96% after 10 to 21 years).6 In this context, Rosetta SM lithium disilicate ceramic (Hass, Gangneung, Korea) has been introduced, which, according to the manufacturer, presents high translucency, opalescence, and resistance due to its microcrystal structure, providing greater performance and simplified fabrication technique using computeraided design/computer-aided manufacturing (CAD/ CAM).. Excessive acid etching results in excessive number of compromised and loosely adhered crystals, preventing the resin cement from bonding micromechanically to the ceramic, which decreases the bond strength between the two materials.

Objectives

Methods

Results

Discussion

Conclusion