Evaluation of enamel damages following orthodontic bracket debonding in fluorosed teeth bonded with adhesion promoter.
OBJECTIVE
To evaluate shear bond strength (SBS) of the orthodontic brackets bonded to fluorosed and nonfluorosed teeth using Light Bond with and without adhesion promoters and compare their enamel damages following debonding.


METHODS
In this study, 30 fluorosed (Thylstrup and Fejerskov Index = 4-5) and 30 nonfluorosed teeth were randomly distributed between two subgroups according to the bonding materials: Group 1, fluorosed teeth bonded with Light Bond; Group 2, fluorosed teeth bonded with adhesion promoters and Light Bond; Group 3, nonfluorosed teeth bonded with Light Bond; Group 4, nonfluorosed bonded with adhesion promoters and Light Bond. After bonding, the SBS of the brackets was tested with a universal testing machine. Stereomicroscopic evaluation was performed by unbiased stereology in all teeth to determine the amount of adhesive remnants and the number and length of enamel cracks before bonding and after debonding. The data were analyzed using two-way analysis of variance, Kruskal-Wallis, Wilcoxon Signed Rank, and Mann-Whitney test.


RESULTS
While fluorosis reduced the SBS of orthodontic bracket (P = 0.017), Enhance Locus Ceruleus LC significantly increased the SBS of the orthodontic bracket in fluorosed and nonfluorosed teeth (P = 0.039). Significant increasing in the number and length of enamel crack after debonding was found in all four groups. There were no significant differences in the length of enamel crack increased after debonding among four groups (P = 0.768) while increasing in the number of enamel cracks after debonding was significantly different among the four groups (P = 0.023). Teeth in Group 2 showed the highest enamel damages among four groups following debonding.


CONCLUSIONS
Adhesion promoters could improve the bond strength of orthodontic brackets, but conservative debonding methods for decreasing enamel damages would be necessary.
Department of Orthodontics, School of Dentistry, Yasuj University of Medical Sciences, Yasuj, Iran.
Tahreh
T
Baherimoghadam
Department of Operative Dentistry, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran.
Sahar
S
Akbarian
Department of Orthodontics, School of Dentistry, Shahed University of Medical Science, Tehran, Iran.
Reza
R
Rasouli
Department of Orthodontics, School of Dentistry, Islamic Azad University, Shiraz, Iran.
Navid
N
Naseri
Dental debonding; dental fluorosis; orthodontic bracket