WIth the development of new adhesive systems and manufacturers reccomending shorter polymerization periods for dental adhesives, there is great concern about the quality of the bond. Objectives : The purpose of this study was to evaluate the effect of polymerization time on adhesive/resin dentin bond strengths. Materials and Methods: Seventy-five extracted human third molars were ground to expose middle dentin and randomly assigned to groups according to adhesive system and polymerization time. The adhesive systems were Single Bond Universal (SBU), Optibond Solo Plus (OS), Single Bond (SB), Clearfil SE Bond (CSE) and Optibond All in one (OA). All adhesives were polymerized with a quartz tungsten halogen light (450mW/cm2) for 10, 20, or 40 seconds and then restored with Z350XT composite. All specimens were stored in water at 37°C for 24h, and then sectioned in beams ( 0.8 X 0.8 mm) for microtensile bond test. Data were analyzed with one-way ANOVA and Tukey test (p<0.05). Results :
Mean Microtensile Bond Strength and Standard Deviation (MPa±SD) | |||||
| SBU | OS | SB | CSE | OA |
10 sec | 27.1 ± 3.9a | 20.5 ± 2.5 c | 23.2 ± 2.2 e | 20.1 ± 3.7 g | 18.6 ± 3.6 i |
20 sec | 27.7 ± 8.8 a | 25.1 ± 2.7 c | 26.5 ± 4.9 e | 31.5 ± 2.9 g | 20.0 ± 7.1 i |
40 sec | 27.9 ± 6.2 a | 26.6 ± 5.1 d | 31.9 ± 2.4 f | 34.0 ± 6.5 h | 27.4 ± 5.9 j |
Different superscript letters indicate statistical significance within a column (p<0.05). | |||||
Conclusion : Except for Single Bond Universal, bond strengths significantly increased with elapsed polymerization time. Despite the demand by clinicians for reduced polymerization time, this may be the cause of many restorative failures.