All groups displayed clinically acceptable mean bond selleck inhibitor strengths (over 8 MPa). ANOVA indicated a significant difference between groups (P<.001) (Table 1). Highest values of SBS were measured in group III. SBS in group II were significantly lower than groups I, III and IV (P<.001). No significant difference was found between groups I, III and IV (P<.05). Figure 1 Shear bond strengths (in MPa) of the groups. Results presented as boxplots. Horizontal line in middle of each boxplot shows median value; horizontal lines in box indicate 25% and 75% quartiles; lines outside box indicate 5% and 95% quartiles. Table 1 The results of the ANOVA comparing the SBS of the groups. Frequency distribution of the ARI scores and the chi-square comparison of the test groups are presented in Table 2.

There was significant difference between groups. There was a greater frequency of ARI scores of 1,2 and 3 in group II (Light Bond+Fluorosis). Table 2 Frequency distribution of the ARI scores and the chi-square comparison of the test groups. DISCUSSION This study was designed to evaluate the effects fluorosis and SEP on SBS of orthodontic brackets. For this purpose, fluorosed teeth (TFI score 4) were collected and selected by two examiner��s agreement (N.A, H.T). Since fluoride content can vary between different teeth, only fluorosed human maxillary premolar teeth were used in this study.16 Fluorosed teeth have the highest concentration of fluoride in the outer 200 ��m of enamel surface.17 Weerasinghe et al16 removed this hypermineralized, acid resistant enamel surface before the shear test.

Since this procedure is not suitable for orthodontic practice, we did not remove the enamel surface layer in our study. Despite the statistical differences between the groups, all groups displayed clinically acceptable mean bond strengths (over 8 MPa).18 Etch&rinse adhesive procedure has been used for years to bond orthodontic brackets to fluorosed or nonfluorosed enamel. Ng��ang��a et al19 have reported that there were no differences between SBS of brackets to fluorosed or nonfluorosed enamel. On the other hand, Adanir et al3 found that severity of fluorosis affected the SBS of a etch&rinse bonding system to fluorosed enamel. They recommended using an adhesion promoter to enhance bond strength of brackets when bonding composite resin to the fluorosed enamel.

20 The findings of the present study demonstrated that fluorosis significantly reduced the SBS of the brackets with standard etch&rinse protocol. The results are in agreement with previously published studies.3,20,21 Therefore, first part of the null hypothesis was rejected. To reduce chair time and increase cost effectiveness, AV-951 alternative enamel conditioners such as SEP has been recommended for bonding of brackets. Transbond Plus SEP is a dental adhesive system developed for orthodontic bonding. When this SEP is used, the mean SBS of the fluorosed and non-fluorosed groups were 21.22 �� 3.47 and 22.