title: Enamel shear bond strengths after vital bleaching.
abstract: This study examined the shear bond strengths of enamel bond formed at specific time intervals after the termination of vital bleaching. A total of 160 extracted human anterior teeth were divided into three bleaching treatment (BTx) groups (Superoxol, Proxigel, White & Brite), two bonding agent (BA) subgroups (Scotchbond Dual Cure, Scotchbond 2) and two BA control groups. After BTx for 30 days, bonds were formed at 1, 6 and 24 hours; 3 and 7 days (time interval, TI) post-termination of BTx. A total of 32 groups of n = 5 were used. Bonds were formed in nylon tubes with selected BA and Silux Plus, and ruptured 24 hours later with Instron and cable/loop to measure enamel shear bond strength (SBS). A 3 x 2 x 5 factorial ANOVA and Tukey 95% confidence interval (TCI) detected significant differences between BTx (F = 3.54; TCI = 2.7 MPa), BA (F = 9.73; TCI = 1.8 MPa) and TI (F = 9.39; TCI = 4.1 MPa). The interaction between BTx and TI was slightly significant (F = 2.02); other interactions were not significant. Post-hoc analysis showed 80% of bonds failed at the interface or by mixed cohesive composite/interfacial failure. Scanning electron microscope observations suggested association of increased density of voids in bond area at TI with lowest mean bond strengths. SBS ranged from 42.3 to 106.8% of control.
authors.affiliation: Dental Branch, University of Texas Health Science Center, Houston, 77225.
authors.forename: R S
authors.initials: RS
authors.lastname: McGuckin
authors.forename: B A
authors.initials: BA
authors.lastname: Thurmond
authors.forename: S
authors.initials: S
authors.lastname: Osovitz
mesh_terms: D000704:Analysis of Variance; D000077463:Carbamide Peroxide; D003188:Composite Resins / Q000737:chemistry; D003481:Cuspid; D001840:Dental Bonding; D003743:Dental Enamel / Q000187:drug effects*; D017220:Dentin-Bonding Agents / Q000737:chemistry; D004338:Drug Combinations; D006801:Humans; D006861:Hydrogen Peroxide / Q000009:adverse effects; D007180:Incisor; D008422:Materials Testing; D010545:Peroxides / Q000009:adverse effects; D019279:Resin Cements; D013718:Tensile Strength; D014073:Tooth Bleaching / Q000009:adverse effects*; D014508:Urea / Q000009:adverse effects / Q000031:analogs & derivatives
chemical_list: D003188:Composite Resins; D017220:Dentin-Bonding Agents; D004338:Drug Combinations; D010545:Peroxides; D019279:Resin Cements; C067788:scotchbond 2; D000077463:Carbamide Peroxide; D014508:Urea; C041330:Scotchbond; D006861:Hydrogen Peroxide