Effect of surface conditioning agents on the repair bond strength of an indirect hybrid composite

Noriko Hisamatsu, DDS, PhD,(a) Mitsuru Atsuta, DDS, PhD,(b) and Hideo Matsumura, DDS, PhD(b)

(a)Fixed Prosthodontics Division, Nagasaki University Hospital of Dentistry, and (b)Department of Fixed Prosthodontics, Nagasaki University School of Dentistry, Nagasaki, Japan

Purpose: The objective of the current study was to evaluate the effect of silane primers and unfilled resin bonding agents when used for bonding between layers of a light-activated indirect composite material (Cesead II).
Materials and Methods: Disk specimens were prepared with the dentin portion of the composite material and abraded with a silicon-carbide rotary cutting instrument. The specimens were conditioned with varying combinations of silane primer (Add-on Primer, Clearfil Porcelain Bond Activator, Clearfil Porcelain Bond Activator + Clearfil Mega Bond-Primer, Porcelain Liner M, unprimed) and bonding agent (Clearfil Mega Bond-Bond, Modeling Liquid, Stain Diluent, no-bonding agent). After placement of the enamel portion of the same brand of composite material on each surface of the dentin material, the specimens were light-exposed, and either wet- or dry-stored at 37°C for 24 hours. Shear bond strengths were determined and the results were analyzed by analysis of variances and post-hoc tests (p<0.05).
Results: Of the combinations tested, the Add-on Primer or Porcelain Liner M silane material combined with the Modeling liquid or Stain Diluent bonding agent showed the greatest bond strength. The groups with no bonding agent generally resulted in poor repair bond strength.
Conclusion: The use of specific combinations of silane primer and bonding agent is recommended to achieve reliable 24-hour bond strength between layers of the Cesead II composite.
(Int Chin J Dent 2002; 2: 5-14.)

Clinical Significance
: The results of the current study demonstrate that the ground surface of a hybrid composite material (Cesead II) can be repaired in dental laboratories by combined application of a silane primer and a light-activated bonding agent, if the composite material has not aged in the oral environment.
Key Words: bonding, composite, repair, silane.