Effect Of Various Surface Treatments On The Shear Strength Of Orthodontic Brackets In Dental Fluorosis Fixation

Objective:To evaluate the effect of various surface treatments on the shear Strength and ARI index of orthodontic brackets in dental fluorosis fixation.Methods:Totally 90 premolars of dental fluorosis were randomly assigned into six groups and socked in artificial saliva for 2 weeks before testing. The first abrading group (n=15), the sandblasting group (n=15), and the silicone particles treatment group (n=15); the abrading +sandblasting group (n=15), the abrading +silicone particles group (n=15). Then all the samples were cleaned with 75% alcohol, dried, acid etching 1 min, light-cure bond routinely for 40 seconds.The shear strength was measured using tensile force apparatus; observing the ARI, the residual binderon the teeth facing was observed under microscopy. The treated teeth surfaces were examined with scanning electronic microscopy;Results:1.①Shear bond strength:The shear bond strengths were (5.045±0.945) in group F, (9.39±1.54) in group A,(6.45±1.275) in group B,(8.898±1.3659) in group C,(5.805±1.065) in group D and (8.85±1.7) in group E. There were statistically significant differences with the group F (P<0.05).2. After adhesive bonding, the difference of the ARI scores between the groups was not significant (P> 0.05). But the group of E had the lowest ARI scores.3. After adhesive bonding, the scanning electron microscope morphologies of the groups were significantly different. Porcelain surfaces of the group E. Compared with the group F, the abrading groups had the longer length of tags.Conclusions:It is concluded that strong shear strength may be obtained by abrading +silicone particles on the surface of the teeth and it had lower ARI.