Study On Microleakage Of Resin Filling After Bleaching In Dead Teeth

Objective: The degree of microleakage of resin is measured after bleaching extracted teeth and filling resin into extracted teeth immediately or lingeringly. The degree of microleakage of resin is tested after using different bleaching methods and different time filling.Methods: 42 premolar teeth are divided into 7 groups randomly. Group A is control group: after root canal treatment routinely, immediately do the resin filling into the teeth;group B: after root canal treatment routinely, bleached by BEYOND cold light whitening gel for 3 weeks,then do the resin filling into the teeth; group C: after root canal treatment routinely, bleached by BEYOND cold light whitening gel for 3 weeks, then stored the teeth in artificial saliva for two weeks and do the resin filling into the teeth; group D: after root canal treatment routinely, bleached by BEYOND cold light whitening gel for 3weeks, then stored the teeth in artificial saliva for four weeks and do the resin filling into the teeth; group E: after root canal treatment routinely, bleached by odium perborate for 3weeks,then do the resin filling into the teeth; F: after root canal treatment routinely,bleached by sodium perborate for 3 weeks, then stored the teeth in artificial saliva for two weeks and do the resin filling into the teeth; group G: after root canal treatment routinely,bleached by sodium perborate for 3 weeks, then stored the teeth in artificial saliva for four weeks and do the resin filling into the teeth;. All the teeth are thermally cycled. Then all teeth are immersed in 2% methylene blue; the buccolingual direction is sliced; the situation of dye penetrant is observed under stereoscopic microscope.Results: The average micro leakage of group B and group E are significantly greater than that of the other groups(P < 0.05), significant difference was observde between group B and group E(P < 0.05); No significant difference was observed among group A,C,D,F and G(P > 0.05).Conclusion: The microleakage of resin is increased if instantly bonding resin after the tooth bleaching. Among which Beyond cold light whitening gel group is bigger than the micro leakage of sodium perborate. If delayed two weeks after bleaching, the micro leakage of adhesive resin is reduced, and reached the level of unbleached group.