The effect of bleaching on shear bond strength of brackets bonded with a resin-modified glass ionomer.
BACKGROUND
This study assessed the effect of a 35% hydrogen peroxide bleaching gel on the shear bond strength and bond failure site of a resin-modified glass ionomer (Fuji Ortho LC, GC Europe, Leuven, Belgium).


METHODS
Forty-five bovine mandibular permanent incisors were randomly divided into 3 groups; each group contained 15 teeth. Bleaching treatment was performed at 2 different times before the bonding procedure. Forty-five stainless steel brackets were bonded with the resin-modified glass ionomer. After bonding, all samples were stored in distilled water for 24 hours and then tested in shear mode on a testing machine.


RESULTS
Group 1 (no bleaching) showed significantly higher shear bond strength values than groups 2 (bleaching immediately before bonding) and 3 (bleaching 1 week before bonding). No significant differences were found between groups 2 and 3. Moreover, no significant differences in debond locations were found among the 3 groups.


CONCLUSIONS
Bleaching treatment before bonding significantly lowered the bond strength values of Fuji Ortho LC.
Cacciafesta
Vittorio
V
Department of Orthodontics, University of Pavia, Pavia, Italy. vcacciafesta@hotmail.com
Sfondrini
Maria Francesca
MF
Stifanelli
Paola
P
Scribante
Andrea
A
Klersy
Catherine
C
D000180:Acrylic Resins; D000538:Aluminum Silicates; D000704:Analysis of Variance; D000818:Animals; D002417:Cattle; D016009:Chi-Square Distribution; D003188:Composite Resins; D003722:Dental Alloys; D001840:Dental Bonding; D003743:Dental Enamel; D003799:Dental Stress Analysis; D005899:Glass Ionomer Cements / Q000737:chemistry; D006861:Hydrogen Peroxide; D008422:Materials Testing; D016910:Orthodontic Brackets; D016877:Oxidants; D011897:Random Allocation; D033081:Shear Strength; D013193:Stainless Steel; D018709:Statistics, Nonparametric; D014073:Tooth Bleaching
D000180:Acrylic Resins; D000538:Aluminum Silicates; D003188:Composite Resins; D003722:Dental Alloys; C095451:Fuji Ortho LC; D005899:Glass Ionomer Cements; D016877:Oxidants; D013193:Stainless Steel; D006861:Hydrogen Peroxide