title: Modification of 4-META/MMA-TBB resin for safe debonding of orthodontic brackets--influence of the addition of degradable additives or fluoride compound.
abstract: The purpose of this study was to evaluate the performance of modified 4-META/MMA-TBB resin cements (Superbond C&B) in terms of debonding orthodontic brackets easily and safely from enamel without the loss of proper bracket bond strength. Poly (DL-lactide-co-glycolide) (PLGA), calcium fluoride (CaF2), or alpha-tricalcium phosphate (alpha-TCP) was added to the polymer powder of 4-META/MMA-TBB resin, and the shear bond strength of orthodontic brackets to human enamel using modified resins was measured before and after 10,000-cycle thermal cycling test between 5 degrees C and 55 degrees C. The modified resins tended to provide lower bond strength compared with the original 4-META/MMA-TBB resin. However, alpha-TCP- or CaF2-modified resin showed no significant differences in bond strength before and after thermal cycling. Moreover, there was a tendency of more residual resin remaining on the tooth surface after debonding, thereby suggesting a lower risk of enamel fracture. In conclusion, alpha-TCP- or CaF2-modified 4-META/MMA-TBB resin seemed to allow easy and safe debonding of orthodontic brackets without loss of proper bracket bond strength.
authors.affiliation: Department of Orthodontics, Nihon University Graduate School of Dentistry at Matsudo, Chiba, Japan. Kawabata.rihito@nihon-u.ac.jp
authors.forename: Rihito
authors.initials: R
authors.lastname: Kawabata
authors.forename: Tohru
authors.initials: T
authors.lastname: Hayakawa
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Kasai
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D000704:Analysis of Variance; D001896:Boron Compounds / Q000737:chemistry*; D016009:Chi-Square Distribution; D017005:Dental Debonding / Q000379:methods*; D003764:Dental Materials / Q000737:chemistry; D005459:Fluorides / Q000737:chemistry*; D006801:Humans; D008689:Methacrylates / Q000737:chemistry*; D008768:Methylmethacrylates / Q000737:chemistry*; D016910:Orthodontic Brackets; D033081:Shear Strength
chemical_list: D001896:Boron Compounds; D003764:Dental Materials; D008689:Methacrylates; D008768:Methylmethacrylates; C049495:Super-bond; D005459:Fluorides