The effects of fluoride releasing orthodontic sealant on the shear bond strength of light-and chemical-cured orthodontic resins

Kim, Bong Hyun; Yoon, Young Jooh; Kim, Kwang Won

Abstract

The purpose of this study was to evaluate the effects of fluoride relasing orthodontic sealant on the shear bond strength of light-and chemical-cured orthodontic resins, compare the sheat bond strenth with light-and chemical-cured orthidintic resins, and to identify the changes of shear bond strength by rebonding in vito. The brackets were divided into eight groups. Each group of metal grackets had different bonding mechanisms with adhesives. Group A : Transbond only Group B : Mono-Lok2 only Group C : Light cured FluoroBond+Transbond Group D : Light cured FluoroBond+Mono-Lok 2 Group E : Transbond only(rebonded) Group F : Nomo-Lok 2 only(rebonded) Group G : Light cured FluoroBond+Transbond(rebonded) Group H : Light cured FluoroBond+Mono-Lok 2(redonded) 65 extracted human premolars were prepared for bonding and 65 metal brackets for each group were bonded to prepared enamel surfaces of buccla surfaces as the above prescription. 24 hours bonding after, the Instron universal testing machine was usedto test the shear bond strength of metal brackets to enamel. After debonding, same kind of metal brackets for each group wrer rebonded to prepared enamel surfaces of buccal surfaces to test the shear bond strength at the rebonding to enamel. Statistical analysis of data was carried out Student's t-test ANOVA test, and Scheffe test using SPSS/PC+. The results were as follows : 1. The order of bond strength was Group B(11.84MPa), Group A(10.75MPa), Group D(9.69MPa), and Group C(9.39MPa) in 1st bonded groups. 2. The order of shear bond stermgth was Group E(7.40MPa), Group G(6.48MPa), Group F(5.89MPa), and Group H(5.15MPa) in rebonded groups. 3. The shear bond strength of chemical cured orthodontic resins had higher than that of light-cured orthodontic resins in all groups, but there was no statistical significance between groups(P>0.05). 4. In rebonded groups, the shear bond strength of light cured orthodontic resins had higher than that of chemical cured orthodontic resins, but there was no statistical significance between grouops(P>0.05). 5. The shear bond strength of all rebonded groups progressively decreased than that of 1st bonded groups, and there was statistical significance between groups(P<0.05, P<0.001).