Effects of long-term repeated topical fluoride applications and adhesion promoter on shear bond strengths of orthodontic brackets

Abstract

Objective:The purpose of this study was to assess the effects of long-term repeated topical application of fluoride before bonding and an adhesion promoter on the bond strength of orthodontic brackets.Materials and Methods:A total of 76 bovine incisors were collected and divided equally into four groups. In group 1, the brackets were bonded without topical fluoride application or adhesion promoter. In group 2, before bonding, the adhesion promoter was applied to nonfluoridated enamel. In group 3, the brackets were bonded without the application of the adhesion promoter to enamel, which had undergone long-term repeated topical fluoride treatments. Teeth in group 4 received the long-term repeated topical applications of fluoride, and the brackets were bonded using the adhesion promoter. All the brackets were bonded using BeautyOrtho Bond self-etching adhesive. The shear bond strength was measured and the bond failure modes were evaluated with the use of the adhesive remnant index (ARI) after debonding.Results:The mean shear bond strength was significantly lower in group 3 than in groups 1, 2, and 4, and there were no significant differences between the groups except for group 3. There were significant differences in the distribution of ARI scores between groups 2 and 3, and between groups 3 and 4.Conclusions:The adhesion promoter can recover the bond strength reduced by the long-term repeated topical applications of fluoride to the prefluoridation level and had a significantly great amount of adhesives left on either fluoridated or nonfluoridated enamel.

Effect of different white-spot lesion treatment on orthodontic shear strength and enamel morphology: In vitro study

“…This result was consistent with the experiments by Bayrak et al [20] and Endo et al, [21] in which fluoride varnish was applied before bracket attachment to human tooth samples using RMGIC bonding agent. Nonetheless, this result was inconsistent with a study by Nhan et al, [22] in which fluoride varnish application did not contribute to the difference of shear strength of brackets bonded with composite resin bonding agent and phosphoric acid etch.…”

Bond strength of indirect bonded brackets in orthodontic adhesives with different viscosities

“…In this study, medium and low viscosity IDBSs with the adhesion promoter had lower frequencies of bond failure at the enamel-adhesive interface than those without this promoter, as shown in a previous study 24) . These results may be caused by the speculation that the combination of adhesion promoter and the BOB SEP moderately demineralizes enamel and enhances mechanical bonding between the adhesive and enamel surface, as previously mentioned.…”

“…In this study, in all three IDBSs, application of an adhesion promoter containing polyacrylic acid gave a significantly higher SBS than in the case of nonapplication of this promoter. Some studies have shown that adhesion promoters significantly increase SBSs 7,8,24) , as evidenced by this study, while others showed that any adhesion promoters did not significantly increase the SBS 25) . Es-souni et al 26) reported that polyacrylic acid leached calcium and phosphorus from hydroxyapatite, and formed a fine polymeric film on the enamel surface.…”

Shear bond strength of orthodontic brackets bonded with resin coating material

“…Based on these previous findings, our result showing that the RMGIC system (group 1, 11.7 MPa) exhibited a significantly higher mean SBS than the BOB system combined with the self-etching primer (group 2, 9.6 MPa) might be expected. In both the RMGIC system and BOB system combined with the self-etching primer, the chemical bonding mechanism between the adhesive and buccal enamel is considered to be superior to mechanical adhesion 15,16) . This is consistent with our SEM findings that buccal enamel treated with both 10% polyacrylic acid (Fig.…”