Using Organoselenium-Containing Sealant in Bonding Orthodontic Brackets: Two-versus-One Step Curing

Objectives: This study compared the shear bond strength (SBS) when using two-step versus one-step curing methods in bonding orthodontic brackets while using an antimicrobial organoselenium-containing sealant (DenteShield^TM) to serve dual functions of priming enamel prior to bonding and protecting enamel against white-spot lesion formation.
Methods: 250 extracted human molars were randomly assigned to 10 experimental groups (n=25/group). Five of the groups were assigned to ‘Two-step’ curing group and five were assigned to ‘One-step’ curing group. Five different products, DenteShield^™ primer, DenteShield^™ Surface sealant, Reliance Assure PLUS (AP) bonding resin, Reliance Pro Seal (PS), and 3M L-Pop Self-etching primer (Self-etching), were used as primer to conditioned the enamel in both two-step and one-step groups before identical Stainless steel brackets were bonded to the tooth surface using 3M Transbond XT adhesive. The specimens were thermocycled 1000 times using waterbath maintained at 5°C and 55°C for 24 hours before debonding using a universal testing machine. Intra-material comparison of curing methods were performed by two-sample t-tests while Kruskal-Wallis test followed by Dunn’s test was used for multi-group comparisons.
Results: With two-step curing, there was no significant difference in SBS between DenteShield^™ primer and DenteShield^™ sealant, but the SBS of these two materials are significantly (p<0.0001) higher than those of AP, PS and Self-etch. These three later materials did not differ from each other in their SBS. In general, SBS was lower in all materials when the bonding was cured by one-step than two-step; however, this difference was only statistically significant in DenteShield^™ primer (p<0.0001), DenteShield^™ sealant (p<0.0001) and AP (p<0.001).
Conclusions: DenteShield^™ sealant can serve as primer as well as anti-demineralization sealant during orthodontic treatment without adversely affecting the SBS of the bracket. Except with Pro Seal or Self-etching primer, the materials should be cured by two-step for adequate bond strength.