Effect of different surface treatment techniques on the repair strength of indirect composites.
OBJECTIVE
Composite resin restorations present high survival rates and when a failure occurs repair is often possible. The aim of this study was to assess the effect of various repair techniques on indirect restorations.


METHODS
LAVA Ultimate (3M), and Clearfil Estenia blocks (Kuraray) were repaired with our without surface roughness treatments, silane application and artificial ageing. Micro-shear bond stress tests were performed, while cohesive strength served as positive control. ANOVA was used for cohesive strength and effect of ageing, and linear mixed models to evaluate the effect of treatment variables on repair strength.


RESULTS
Both materials reacted differently on surface treatments. Untreated (no treatment, no silane) repair strength was 16.3±6.3MPa for LAVA Ultimate and 19.0±4.3MPa for Estenia. Thermal cycling resulted in a 14-58% reduction of cohesive strength. Without cycling, all treatments resulted in a significant increase of bond strength in LAVA Ultimate (p<0.003). After cycling use of air-abrasion showed a positive trend for both substrates, significantly effective for LAVA Ultimate (p<0.04), and silane and CoJet for Estenia (p<0.024). The positive effect of HF treatment disappeared after cycling.


CONCLUSIONS
It may be concluded that (1) the effect of surface treatment procedures on the repair bond strength of indirect composites is depended on the substrate and ageing. (2) Silane did not have a clear overall positive effect on bond strength and (3) artificial ageing had a strong negative influence on the stability of the adhesive interface and on the cohesive strength of one indirect composite resin material, but not the other.
Radboud university medical center, Radboud Institute for Health Sciences, Department of Dentistry, Nijmegen, The Netherlands. Electronic address: bas.loomans@radboudumc.nl.
B A C
BA
Loomans
Graduate Program in Dentistry, School of Dentistry, Federal University of Pelotas, Pelotas, Brazil.
M E
ME
Mesko
Graduate Program in Dentistry, School of Dentistry, Federal University of Pelotas, Pelotas, Brazil.
R R
RR
Moraes
Radboud university medical center, Radboud Institute for Health Sciences, Department of Dentistry, Nijmegen, The Netherlands.
J
J
Ruben
Radboud university medical center, Radboud Institute for Health Sciences, Department of Dentistry, Nijmegen, The Netherlands.
E M
EM
Bronkhorst
Graduate Program in Dentistry, School of Dentistry, Federal University of Pelotas, Pelotas, Brazil.
T
T
Pereira-Cenci
Radboud university medical center, Radboud Institute for Health Sciences, Department of Dentistry, Nijmegen, The Netherlands.
M C D N J M
MC
Huysmans
D000134:Acid Etching, Dental; D020906:Air Abrasion, Dental; D003188:Composite Resins / Q000737:chemistry*; D001840:Dental Bonding; D045662:Dental Etching; D003764:Dental Materials / Q000737:chemistry; D058250:Dental Restoration Repair; D003799:Dental Stress Analysis; D006801:Humans; D008422:Materials Testing; D008689:Methacrylates / Q000737:chemistry*; D011140:Polyurethanes / Q000737:chemistry*; D012044:Regression Analysis; D019279:Resin Cements / Q000737:chemistry; D033081:Shear Strength; D012821:Silanes / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D013718:Tensile Strength
D003188:Composite Resins; D003764:Dental Materials; D008689:Methacrylates; D011140:Polyurethanes; D019279:Resin Cements; D012821:Silanes; C091839:urethanetrimethacrylate
Air-abrasion; Dental adhesion; Dental materials; Dental restorations; Etching; Indirect composite resin; Intra-oral repair; Thermal cycling