[ effect of the light activation mode on incompatibility between one-bottle adhesives and light-cured composites: an in-vitro shear bond strength study]

ABSTRACT

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. The 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. The 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 and Board NT [P and B NT] were [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 1mm/min. The SBS was recorded in MPa. Statistical analysis included two way ANOVA with a significance level of 0.05. The highest SBS [MPa] was shown in OS conventional group [19.62] and the lowest in P and B NT, PDII [5.43]. In each group of 5 curing mode, mean SBS in P and B NT was significantly lower than that in OS as follows In conventional; P and B NT [17.27] vs OS [19.82] in SSI; P and B NT [10.89] vs OS [13.09] in SSII; P and B NT [14.48] vs. OS [18.79] in PDI; P and B NT [5.93] vs OS [11.97] and in PDII; P and 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 PDIpaired comparisons of curing modes showed significant differences [p<0.05]. The bond strength of P and 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