بررسی آزادسازی فلوراید و استحکام برشی پیوند سمان های رزینی خود باند شونده جهت چسباندن براکت های ارتودنسی

objective: the objective of this study was to investigate the invitro fluoride release of four new self-adhesive resin cements; set (sdi, australia), breeze (pentron, usa), embrace wetbond (pulpdent, usa), g-cem (gc, japan) and to assess the bonding performance of these self-adhesive resin cements for bonding of orthodontic brackets. materials and methods: for fluoride release experiment, six discs (8mm diameter and 2mm height) were prepared for each self-adhesive cement. transbond xt (3m unitek, usa) and fuji ortho lc (gc, japan) served as negative and positive control group, respectively. the fluoride release of each disc into 5 ml of deionized water was measured at 1,2,3,7,14,28 and 56 days using a fluoride ion-selective electrode connected to an ion analyzer. to prevent cumulative measurements, the storage solutions were changed daily. for sbs experiment, 135 freshly extracted human maxillary premolars were used and divided into 9 groups of 15 teeth. in each group the brackets were cemented by an etch-and-rinse control (transbond xt) and four self-adhesive resin cements with and without prior acid etching. the specimens were stored in distilled water and subjected to 3000 thermocycles between 5° c and 55° c. the brackets were then deboned in shear with a testing machine. after deboning, the enamel surface was examined under 10 x magnifications to determine the amount of residual adhesive remaining on the tooth. the results were analyzed with anova and inter-group differences were investigated with tukey post-hoc test at 0.05 level. the kruskal-wallis test was used to compare the adhesive remnant index (ari) scores. results: statistically significant differences were found in fluoride released rates, with fuji ortho lc releasing the most, followed by wetbond, breeze, g-cem and set, respectively. these differences were all significant (p<0.05). the sbs of brackets cemented with transbond xt were significantly higher than those of self-adhesives (p<0.05). however, when the self-adhesive resin cements used with enamel etching, no significant differences was found in the sbs compared with transbond xt, except for breeze. after enamel etching, breeze showed significantly higher sbs than transbond xt (p<0.001).the comparisons of the ari scores indicated that bracket failure modes were significantly different (p<0.001). conclusion: self-adhesive resin cements had significant long term fluoride release and all could be recommended as suitable fluoride-releasing orthodontic bonding materials. the best bonding effectiveness with these cements were obtained by enamel acid-etching prior to bracket bonding. key words: fluoride release, shear bond strength, self-adhesive resin cements.