Usefulness of orthodontic adhesive-containing fluorescent dye

Abstract

Orthodontic adhesive is often left on the tooth surface when a multibracket appliance is debonded, and it is difficult to remove because its colour is similar to that of the tooth. If the adhesive changed colour during debonding, residual adhesive could be more easily removed. This in vitro study evaluated the usefulness of adhesive mixed with a small amount of fluorescent dye for clinical orthodontics. Sixty-four metal brackets were bonded to flattened bovine enamel surfaces using adhesives with three concentrations (0.001, 0.002, and 0.003 per cent) of fluorescent dye, and the shear bond strength (SBS) and adhesive remnant index (ARI) scores for each adhesive were determined. Colour penetrating through the transparent bracket was measured using a colour analyser. SBS and fluorescence intensity were examined to determine the stability of the adhesives after they were subjected to a thermal cycle test (1000 cycles). For data that were normally distributed, one-way analysis of variance followed by the Student-Newman-Keuls test was used to identify significant differences among the groups. If the data were not normally distributed, the Kruskal-Wallis H-test followed by the Mann-Whitney U-test with Bonferroni correction was used. Differences in ARI were determined with the chi-square test. The SBS of the adhesive with 0.003 per cent fluorescent dye was significantly lower than that of the control (Transbond). In ARI tests, significantly more of the adhesive with 0.003 per cent dye was left on the tooth surface after 24 hours compared with the other adhesives. With regard to colour penetration, the adhesive with 0.003 per cent dye was five times more visible than to others. SBS and fluorescence intensity of the adhesives were not affected by thermal cycling. Therefore, an adhesive containing less than 0.002 per cent fluorescent dye provides both sufficient bond strength for orthodontic brackets and sufficient fluorescent colour for easy visualization without aesthetic impairment.

Do fluorescent agents alter the mechanical strength of orthodontic adhesives? An in vitro and clinical study

“…The present study employed the UV system, though the manufacturer does not state what fluorescent agent is used, just the concentration (< 0.001% by mass). Therefore, this study obtained a shear bond strength greater than that of the abovementioned study [30] for all the adhesives tested, probably due to the bonding having been performed on human teeth. The present study showed significant differences between groups for the ARI scores.…”

“…With the aim of looking for more effective solutions and making adhesives visible, for safe, complete removal after orthodontic treatment, Hamba et al [9] added Eu 3+ ions to yttrium oxide (Y 2 O 3 ), which was a viable alternative for differentiation. Namura et al [30], looked into the effect of incorporating different concentrations (0.001%, 0.002%, and 0.003%) of fluorescent dye derived from coumarin, in an adhesive system for bonding brackets to bovine teeth, and concluded that the adhesive containing 0.002% fluorescent dye possessed good shear bond strength (6.6 MPa), and also facilitated the removal of remaining material without impairing the structure of the enamel. The present study employed the UV system, though the manufacturer does not state what fluorescent agent is used, just the concentration (< 0.001% by mass).…”

Using UV light for adhesive remnant removal after debonding of orthodontic accessories

“…17 When the color of the adhesive system is similar to the natural tooth color, a careful examination with a manual instrument, such as a dental explorer, should be performed after adhesive removal and polishing of tooth surfaces, in order to verify the color more accurately. 18 It should be noted that after polishing, both direct visual (Table 1) and SEM (Table 2) analysis results showed similarities between the removal methods (NL and WL), with a significant increase in the number of samples with no removal marks, or else soft removal marks, thus indicating that the rate of surfaces with evident marks was reduced. This emphasizes the importance of polishing, especially after removal of AR by multi-bladed tips at high speed.…”

A Modified Photoactivation Protocol Using Two Simultaneous Light-Curing Units for Bonding Brackets to Enamel

“…On one hand, one might link the result after thermal cycling to the number of cycles used, which was probably not sufficient to generate significant stress at the bonded interfaces. However, previous studies have also reported that the bond strength of brackets to enamel might not be affected by thermal cycling (19)(20)(21)(22).…”