An Experimental Study Of Bond Strength Between Total-etching And Self-etching Adhesives

Objective The research selected three well-known total-etching adhesives and self-etching adhesives to compare their bond strength with the normal dentin,and it also compared the bond strength between same brand's resin to adhesives and different brand's resin to adhesives,the bond strength between two adhesives and the caries-effected dentin, the bond strength of the caries-effected dentins under different etching time.This research give certain theory instruction for the control of etching time and choose of dentin adhesive on clinic.Methods Experiment 1 Collecting 60 intact human third molar teeth,exposing occlusal dentin and dividing them randomly into 12 groups.Selecting 6 dentin adhesive systems:Excite,Prime&Bond NT and Singlebond2 in total-etching systems,AdheSE, XenoⅢand Adper Prompt in self-etching systems.Bonding each group with one dentin adhesive system according to the manufacturers' directions.Then building up a block of resin composite on it,The dentin-resin composite block was sectioned to obtain 1mm~2 composite-dentin rectangular beams under low-speed saw.These samples were tested in tension in a Micro-tensile tester.Experiment 2 Collecting 40 extracted carious human molars by Snoop(Pulpdent Corporation,USA)and keeping the normal dentin which grounded to expose flat surfaces and the caries lesion was surrounded.Sectioning all teeth to three parts by paralleling the major axis,and then etching them with 35%Gluma etching reagent(or self-etching reagent) for 20,40 and 60 seconds.Selecting each kind of total-etching and self-etching dentin adhesives and using them on the exposed flat surface of dentin,then building up the crown to certain altitude with resin.Cutting the tooth into rectangular shape samples which the cross should be 1mm~2 under low-speed saw,and check them by stereoscope microscope to divide normal dentin with caries-affected dentin,then taking the normal dentin as the comparison.Testing its bond strength by micro-tensile tester,carrying statistics analysis on the result by the software SPSS11.5.Results Experimental result show that there's no significantly difference of bond strength between Excite and AdheSE,Prime & Bond NT and XenoⅢ,Singlebond2 and Adper Prompt(P＞0.05),so do the Prime&Bond NT,Singlebond2 and TPH Resin, XenoⅢ,Adper Prompt and TPH Resin(P＞0.05),Prime&Bond NT,Singlebond2 and Z-100 Resin,XenoⅢ,Adper Prompt and Z-100 Resin(P＞0.05).The bond strength of normal dentin is higher than caries-affected dentin when the etching time is 20s(P＜0.05). Regarding the caries-affected dentin,the bond strength of its 40s group is much higher than the 20s group and the 60s group(P＞0.05);But about the normal dentin,groups of 20s and 40s obtained high dentin adhesive strength,and the bond strength of the 40s group is a little lower than the 20s group,but no significantly difference(P＞0.05).If expanded the etching time to 60s,the dentin bond strength drops obviously,and it has a significantly difference with the 40s group and the 20s group(P＜0.05).Conclusion There is no significantly difference on the bond strength between total-etching and self-etching adhesive systems the normal dentin.Different kinds of adhesives and resins can be used together as it's not influence the bond strength effect. Etching time could influence the bond strength of normal dentin and caries-affected dentin.