Effects of air abrasion with alumina or glass beads on surface characteristics of CAD/CAM composite materials and the bond strength of resin cements

Abstract

Objective The study aimed to evaluate effects of air abrasion with alumina or glass beads on bond strengths of resin cements to CAD/CAM composite materials.Material and Methods CAD/CAM composite block materials [Cerasmart (CS) and Block HC (BHC)] were pretreated as follows: (a) no treatment (None), (b) application of a ceramic primer (CP), (c) alumina-blasting at 0.2 MPa (AB), (d) AB followed by CP (AB+CP), and (e) glass-beads blasting at 0.4 MPa (GBB) followed by CP (GBB+CP). The composite specimens were bonded to resin composite disks using resin cements [G-CEM Cerasmart (GCCS) and ResiCem (RC)]. The bond strengths after 24 h (TC 0) and after thermal cycling (TC 10,000 at 4–60°C) were measured by shear tests. Three-way ANOVA and the Tukey compromise post hoc tests were used to analyze statistically significant differences between groups (α=0.05).Results For both CAD/CAM composite materials, the None group exhibited a significant decrease in bond strength after TC 10,000 (p<0.05). AB showed significantly higher bond strength after TC 10,000 than the None group, while CP did not (p<0.05). GBB exhibited smaller surface defects than did AB; however, their surface roughnesses were not significantly different (p>0.05). The AB+CP group showed a significantly higher bond strength after TC 10,000 than did the AB group for RC (p<0.05), but not for GCCS. The GBB+CP group showed the highest bond strength for both thermal cyclings (p<0.05).Conclusions Air abrasion with glass beads was more effective in increasing bond durability between the resin cements and CAD/CAM composite materials than was using an alumina powder and a CP.

Effect of alumina-blasting pressure on adhesion of CAD/CAM resin block to dentin

“…Strong bonding between CRBs and resin cement depends on micromechanical interlocking and chemical bonding to the surface of the restorative material, which in turn requires cleaning and roughening for adequate surface activation 15) . However, previous studies indicate that alumina-blast flaws are similar in nature to true microcracks 12,[16][17][18][19] . In the present study, alumina blasting improves the µTBS in all groups and with increasing alumina-blasting pressure, the bond strength also tends to increase.…”

“…Without alumina-blasting, free radicals were reported to be insufficient for achieving adhesion between the resin cements and CRB surfaces 12) . The bond strength between CRBs and resin cement is improved by surface treatments such as mechanical treatment and the application of adhesive material.…”

“…Air abrasion with alumina particles cleans the surface and simultaneously increases the surface area 7,8) ; however, it can cause significant damage to the surfaces of the CRBs 9) . To address this issue, many in vitro studies have focused on the surface conditioning of CRBs [9][10][11][12] . However, most of these studies focused on the bonding between the CRBs.…”

Fracture load of CAD/CAM-fabricated and 3D-printed composite crowns as a function of material thickness

“…Several studies are available investigating the bonding strength of composite based CAD/CAM materials [42,43]. Studies assessing the pretreatment method of restorations prior to adhesive luting suggest that the conditioning is predominantly important for composite based CAD/CAM materials [44,45,46]. Strict observance of manufacturer's recommendations for bonding procedure is thus highly mandatory when using composite based CAD/CAM materials.…”

The effect of elapsed time following alumina blasting on adhesion of CAD/CAM resin block to dentin

“…However, CRB has to be pretreated initially to facilitate the retention of silane molecules to promote the wettability of resin cement to CRB surfaces. Nonetheless, silanization only without alumina blasting or alumina blasting only without silanization showed inferior bonding strength 20) compared to combination of them 12,20) .…”