Comparison On The Shear Bond Strength Of Brackets By Using Different Fluid To Treat Enamel-an In-vitro Study

Objective:The purpose of this study was to comparison on shear bond strength (SBS) of brackets by using different kinds of fluid to treat acid-etched enamel contaminated by saliva, and to provide coherent reference for clinical practice.Methods:Collect 100 extracted maxillary premolars for orthodontic treatment, and divide into 5 groups of 20 randomly. After etching and drying, the experimental groups were intentionally contaminated with natural saliva and treated with 5 kinds of fluid as follows:GroupA:distilled water, GroupB:75% alcohols, GroupC:0.25% NaClO solutions, GoupD:0.5% NaCIO solutions, GoupE:1.0% NaCIO solutions. All the specimens were bracket-bonded after drying, incubated in 37℃artificial saliva.The SBS was tested at 30min and 24h by Instron appliance. Evaluated the adhesive remnant index (ARI) by observing the surface of the teeth after debonding. All statistics were analysed by SPSS 15.0 software.Results:(1) The (SBS) of brackets in group B, D and E were higher than in group A and C at 30min and 24h (P<0.05), and there were no significant difference between the SBS of brackets in group A and C, and also between group B, D and E.(P>0.05). (2) The SBS of brackets at 24h was significantly higher than 30min(P<0.01). (3) There were no significant difference of ARI in all groups.Conclusions:(1)Under dying, there were no significant difference between the bond strength of brackets to enamel used 75% alcohols,0.5% and 1.0% sodium hypochlorite solutions to treat acid-etched enamel contaminated by saliva. (2)There were no significant difference between the bond strength of brackets to enamel used distilled water and 0.25% sodium hypochlorite solutions to treat acid-etched enamel contaminated by saliva. (3)Compared to distilled water and 0.25% sodium hypochlorite solutions,75% alcohols,0.5% and 1.0% sodium hypochlorite solutions can better treat acid-etched enamel contaminated by saliva, and increase the bond strength of brackets to enamel.(4)No matter use distilled water,75% alcohols or sodium hypochlorite solutions to treat acid-etched enamel contaminated by saliva, the bond strength in 24 hour was higher than in 30 minute after bracket-bonding.