Influence of surface treatment on bonding of resin luting cement to CAD/CAM composite blocks

Abstract

The aim of this study was to determine the influence of different surface treatments of CAD/CAM composite blocks on bonding effectiveness of resin cements, based on the shear bond strength test and the surface science examination. Specimens were fabricated from two types of CAD/CAM composite blocks (Cerasmart and VITA Enamic), and the specimen surfaces were alumina sandblasted. Specimen surfaces were treated with i) silane, ii) primer, and iii) silane+primer, then two types of cements (Block HC Cem and Super Bond) were bonded. After 24 h storage, bond strengths were measured. Surface free energy measurements were performed of the treated CAD/CAM composite blocks surfaces. The groups ii) and iii) showed significantly higher bond strengths than the group i), apart from VITA Enamic with Block HC Cem. Although the total surface free energy showed different trends in different surface treatments, a similar trend was found in both CAD/CAM composite blocks.

Bonding ability of resin cements to different types of CAD/CAM composite blocks

“…The bond strengths of SA in the early stage of storage period (after 15 min) were relatively lower (12.1-15.6 MPa), then increased after 24 h storage period, and the stable SBS values were obtained even after TC (14.7-19.9 MPa). These results indicated that the incorporation of silane coupling agent in SA was effective in bonding to the CAD/CAM composite blocks as described in previous study 16) . These results indicated that the addition of the silane coupling agent to the hydrophobic paste of SA appeared to be successful, making it possible to simplify the adhesive bonding procedure, which no longer requires separate silanization.…”

“…The bonding procedures using resin cement are important to establish a strong and durable bonding, and the proper treatment of each adherend surface is important to ensure clinical success in obtaining long term durability of the restorations. The application of silane coupling agents or adhesive primers for inner side of CAD/CAM composite restorations are thought to provide stable bonding between the highly cured resin composite and the resin cement 16) . In the current study, the bonding ability of the silane-containing self-adhesive resin cement (SA) and the dual-cured resin cement utilizing the primer (HC) to CAD/CAM composite blocks were evaluated.…”

Shear Bond Strength of a Direct Resin Composite to CAD-CAM Composite Blocks: Relative Contribution of Micromechanical and Chemical Block Surface Treatment

“…Sandblasting significantly increased the SBS values for the dispersed filler composites and PICN. The aim of air abrasion is to increase the surface roughness of the material by creating random irregularities in the matrix, thereby increasing the surface energy [ 2 , 29 ]; this also improves the wettability of the resin composite, which leads to better anchoring by micro-retention [ 30 ]. Sandblasting a CAD-CAM resin also has other advantages, such as cleaning the bonding surface after saliva contamination due to a try-in simulation by providing a fresh and clean surface [ 31 ].…”

“…Increasing the resin wettability by silane application has also been proposed to enhance adhesion to CAD-CAM resin blocks [ 2 ]. In our study, no improvement in SBS values of any CAD-CAM resin block was observed after universal primer use, as in other studies [ 49 , 50 ].…”

“…They promote chairside restorations that lead to reduced work time, which helps in the prevention of SARS-CoV-2 contaminations [ 1 ]. These CAD-CAM resin composite blocks overcome the drawbacks of direct composites, such as insufficient curing or shrinkage stress during light-curing [ 2 ], especially on direct posterior restorations [ 3 ]. Their biocompatibility with the cells of the oral tissues is better than that of direct composites due to their polymerization under high pressure and high temperature during their manufacturing processes [ 4 , 5 ].…”