Repair bond strength of microhybrid, nanohybrid and nanofilled resin composites: effect of substrate resin type, surface conditioning and ageing

Abstract

OBJECTIVES: This study evaluated the microtensile bond strength (MTBS) of non-aged and aged resin-based composites (RBC) (nanohybrid and nanofilled) after two surface conditioning methods, repaired using the composite of the same kind or a microhybrid composite. MATERIALS AND METH-ODS: Nanohybrid (Tetric EvoCeram-TE) and nanofilled (Filtek Supreme-FS) RBC blocks (5 × 5 × 6 mm) (N = 128) were fabricated and randomly divided into two groups: (a) no ageing (control group) and (b) ageing (5.000 thermocycling, 5-55°C). RBC surfaces were polished by up to 1,200-grit silicone carbide papers and conditioned with either (a) air abrasion with 30-m SiO(2) particles (CoJet Sand) for 4 s + silane coupling agent (ESPE-Sil) + adhesive resin (VisioBond) (n = 16) or (b) adhesive application only (Multilink A+B for TE; Adper ScotchBond 1XT for FS) (n = 16). In half of the groups, repair resin of the same kind with the RBC and, in the other half, a different kind of composite (microhybrid, Quadrant Anterior Shine-AS) with its corresponding adhesive (Quadrant UniBond) was used. The specimens were submitted to MTBS test (0.5 mm/min). Data were analysed using three-way ANOVA and Tukey's tests. Degree of conversion (DC) of non-aged and aged resin composites (TE, FS) (n = 3 per group) was measured by micro-Raman analyses. RESULTS: RBC type (p = 0.001) and ageing affected the MTBS results significantly (p = 0.001). Surface conditioning type did not show significant difference (p = 0.726), but less number of pre-test failures was experienced with the CoJet system compared to adhesive resin application only. Repair strength on aged TE showed significantly less (p < 0.05) MTBS than for FS. FS repaired with the same kind of RBC and adhesive resin presented the highest cohesive failures (43 %). DC was higher for TE (71 %) than for FS (58 %) before ageing. CONCLUSION: On the aged RBCs, less favourable repair strength could be expected especially for nanohybrid composite. For repair actions, RBC surface conditioning could be accomplished with either adhesive resin application only or with CoJet system, providing that the latter resulted in less pre-test failures. CLINICAL RELEVANCE: Clinicians could condition the resin surface prior to repair or relayering with either CoJet system or adhesive resin application only, depending on the availability of the system. Abstract Objectives This study evaluated the microtensile bond strength (MTBS) of non-aged and aged resin-based composites (RBC) (nanohybrid and nanofilled) after two surface conditioning methods, repaired using the composite of the same kind or a microhybrid composite. Materials and methods Nanohybrid (Tetric EvoCeram-TE) and nanofilled (Filtek Supreme-FS) RBC blocks (5× 5×6 mm) (N0128) were fabricated and randomly divided into two groups: (a) no ageing (control group) and (b) ageing (5.000 thermocycling, 5-55°C). RBC surfaces were polished by up to 1,200-grit silicone carbide papers and conditioned with either (a) air abrasion with 30-μm SiO 2 particles (CoJet Sand) for 4 s ...

Improving shear bond strength of temporary crown and fixed dental prosthesis resins by surface treatments

“…The effect of sandblasting may be attributed to an increase in the micromechanical retention that elevates the capability of the added bis-acryl resin to interlock mechanically onto the old resin. These results are in close agreement with many investigations reporting improved bond strengths when the filling composite resin was sandblasted before repair [5,7,9,11]. The findings of the current study demonstrate the importance of sandblasting and micromechanical retention in the bis-acryl temporary resin repair.…”

“…Attempts to improve bond strength of restorative materials involve mechanical and chemical means. Many methods have been introduced for modification of a filling composite resin surface: sandblasting, roughening with diamond instrument, abrasive papers, and acid etching [5][6][7]. Several studies have demonstrated that the application of chemical agent, such as bonding agent or silane coupling agent, enhances the bond strength [6][7][8][9][10][11].…”

Effect of surface conditioning methods, adhesive systems and resin composite on repair strength of dimethacrylate and silorane resin composites

“…7 Without the use of adhesive resin significantly lower bond strength results were observed with both LS (5±2.1, 4.5±1.5) and FLS (2.2±1.2, 4.4±1.1) for unground and diamond bur roughened groups, respectively (p<0.0001).…”

“…Resin composite materials used in restorative dentistry offers the advantage of repair approach that prolongs the service life of failed restorations [3][4][5][6][7]. Repair procedures are considered minimal invasive and economic solutions in restorative dentistry since replacement of old restorations yield to removal of sound dental tissues surrounding of the restoration due to the difficulty to distinguish the restoration margins from the cavity walls [8,9].…”

Effect of Different Surface Treatments on Repair Bond Strength of Aged Tooth Colored Materials

“…A study reported that repair bond strength of nanofilled resin composites decreased after thermocycling but no significant difference was noted between the two resin composites tested. [33] This reduction may be due to the bis-GMA and TEGDMA in the nanohybrid resin composite which affect water absorption. [34] In this study, no attempt was done to assess the debonded specimens to determine the mode of failure.…”