Effect of Surface Treatments on Microtensile Bond Strength of Repaired Aged Silorane Resin Composite

Abstract

SUMMARY Objective: This laboratory study compared the repaired microtensile bond strengths of aged silorane resin composite using different surface treatments and either silorane or methacrylate resin composite. Methods: One hundred eight silorane resin composite blocks (Filtek LS) were fabricated and aged by thermocycling between 8°C and 48°C (5000 cycles). A control (solid resin composite) and four surface treatment groups (no treatment, acid treatment, aluminum oxide sandblasting, and diamond bur abrasion) were tested (N=12 blocks, 108 beams/group). Each treatment group was randomly divided in half and repaired with either silorane resin composite (LS adhesive) or methacrylate resin composite (Filtek Z250/Single Bond Plus). After 24 hours in 37°C distilled water, microtensile bond strength testing was performed using a non-trimming technique. Surface topography after surface treatment was analyzed using scanning electron microscopy (SEM). Failure mode was examined using optical microscopy (50×). Results: Weibull-distribution survival analysis revealed that aluminum oxide sandblasting followed by silorane or methacrylate resin composite and acid treatment with methacrylate resin composite provided insignificant differences from the control (p>0.05). All other groups were significantly lower than the control. Failure was primarily adhesive in all groups. Conclusion: Aluminum oxide sandblasting produced microtensile bond strength not different from the cohesive strength of silorane resin composite. After aluminum oxide sandblasting, aged silorane resin composite can be repaired with either silorane resin composite with LS system adhesive or methacrylate resin composite with methacrylate dental adhesive.

Reparability of giomer using different mechanical surface treatments

“…SEM and AFM images in the present study confirmed roughening of the substrate surface and explained the increased repair bond strength after diamond bur surface preparation. Contrary to this study, Palasuk et al reported that use of a diamond bur did not result in a significant increase in repair bond strength of silorane-based composite resin (9). In addition, in a study by Loomans et al , there was no significant difference in repair bond strength of heavily hybrid Clearfil PhotoPosterior composite resin between the control group (with no surface preparation) and the group prepared with a diamond bur (4).…”

“…The results of the present study showed that the repair bond strength of giomer after mechanical surface treatments (air abrasion, Nd:YAG laser and diamond bur) increased significantly, which is consistent with the results of previous studies on resin-based materials, indicating that mechanical roughening of the substrate surface is an important factor in increasing the repair bond strength (9-11,17). An increase in repair bond strength might be attributed to an increase in surface roughness of the substrate and an increase in bonding surface, as confirmed by SEM and AFM images.…”

“…SEM and AFM images in the present study confirmed this. Previous studies (9,12,21) have shown that roughening the surface with air abrasion results in an increase in the repair bond strength of composite resins. Contrary to the results of the present study, Alizadeh et al (10) reported that use of air abrasion did not result in an increase in the repair bond strength of silorane-based composite resin.…”

“…It is essential to prepare the surface of the old composite resin in order to remove its surface layer so that a clean surface with high surface energy and a larger surface area can be achieved for bonding through surface roughening (8). In order to improve bonding during the repair process, different mechanical and chemical surface treatments have been suggested, including use of burs, air abrasion, different lasers, covering the bonding surface with silica, use of hydrofluoric acid, phosphoric acid, silane and finally the use of bonding agents (7-9). Different studies have compared the effects of various surface treatments on the repair bond strength of different composite resins, with different results being reported depending on the type of substrate and preparation technique (5,8,10-13).…”

Repair Strength in Simulated Restorations of Methacrylate- or Silorane-Based Composite Resins

“…In the present study, although repaired with methacrylate-based material, the group with silorane-based material showed predominance of adhesive failures. A previous study showed that after aluminum oxide sandblasting, the aged silorane resin repaired with either silorane resin composite with Filtek LS system adhesive or methacrylate resin composite with methacrylate dental adhesive presented primarily adhesive failures in all groups (20).…”