Document Type : Original Article
Authors
1 Dept. of Operative Dentistry, School of Dentistry, Shiraz University of Medical science, Shiraz, Iran
2 Specialist in Operative Dentistry
Abstract
Statement of problem: Adverse surface interactions between one-bottle adhesives and self – cured composites may occur similarly with light-cured composites during the use of different modes of light activation.Purpose: This study examined the effect of different light activation modes of light-cured composite on the shear bond strength of 2 one-bottle adhesives with different acidity to the dentin.Materials and Method: This experimental study was performed on 110 extracted sound molars. Then, the teeth were randomly divided into 10 equal groups (n=11). One-Step plus (OS) and Prime & Bond NT (P&B NT) were used and followed by respective composite application in 5 light- activation modes of soft conventional, Soft-Start I (SSI), Soft-Start II (SSII), Pulse-Delay I (PDI), Pulse-Delay II (PDII). Then, shear bond strength (SBS) test was performed, using an Instron at 1 mm/min. The SBS was recorded in MPa. Statistical analysis included two way ANOVA with a significance level of 0.05.Results: The highest SBS (MPa) was shown in OS conventional group (19.62) and the lowest in P&B NT, PDII (5.43). In each group of 5 curing mode, mean SBS in P&B NT was significantly lower than that in OS as follows: In conventional; P&B NT (17.27) vs OS (19.82) in SSI; P&B NT (10.89) vs OS (13.09) in SSII; P&B NT (14.48) vs, OS (18.79) in PDI; P&B NT (5.93) vs OS (11.97) and in PDII; P&B NT (11.82) vs OS (16), ( p <0.001). In each of 2 adhesives, ranking of SBS from minimum to maximum was as follows: PDI<SSI<PDII<SSII<C. Two-paired comparisons of curing modes showed significant differences ( p <0.05).Conclusion: The bond strength of P&B NT might be compromised by the higher acidity of this adhesive compared to OS during all of the curing modes especially PDI. The acidity of the adhesive showed the least effect on the conventional mode.Key words: Shear bond strength, One-bottle adhesives, Light-activation mode, Soft-Start, Pulse-Delay, Adhesive acidity.
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