Effect of delayed placement of composite and delayed curing of self etch adhesive system on microleakage of class V composite restorations

Micro leakage is one of the most important complications of direct tooth-colored restorations. the purpose of this investigation was to evaluate the effect of delayed placement of composite and delayed curing of two step self etch adhesive on microleakage of class V composite restorations.

72 class V cavities were prepared in buccal and lingual surfaces of 36 premolars. the specimens randomly assigned into 6 groups. adhesive was photocured in 3of the groups immediately and then composite was applied immediately, with 2min and 5min delay.in the other 3 groups, adhesive was photocured after a 30 second delay and then composite was placed immediately, with 2min and 5min delay. After thermocycling and immersion in 2% methylene blue, the teeth were sectioned and dye penetration was observed under a stereomicroscope and results were analyzed using SPSS17, kruskal wallis and mann whitney test.

kruskal wallis test showed significant difference between groups immediately, 2 and 5minutes delay placement of composite(P =0.001), no significant difference was found between groups immediately and 30 second delaye curing of adhesive(P=0.748). mann whitney test showed significant difference between groups immediately and 2minutes delay placement of composite (P=0.002),and groups immediately and 5minutes delay placement of composite (P=0.001).there was no significant difference between groups with 2 and 5minutes delay in composite placement(P=0.815).

Delayed placement of composite increased micro leakage of class V composite restorations. there was no significant difference between 2 and 5 minutes delay placement of composite.30second delayed curing of adhesive had no significant difference on micro leakage, compared to immediately curing of it.