STATEMENT OF PROBLEM: There is a reduction of dentin bonding strength when the bonding procedure is carried out immediately after bleaching with peroxides. PURPOSE: The aim of this study is to evaluate a proper time interval for in-office bleaching technique using 35% hydrogen peroxide. MATERIAL AND METHODS: Fifty extracted non-caries human third molars were used in this study. Buccal enamel of each tooth was removed and polished by 600 grits silicone carbide paper. They were randomly divided into five groups and bleached 35% hydrogen peroxide except control group. All groups were bonded with Single Bond/Z 350 after each time intervals ; Group-A: control, no bleaching treatment. Group-B: resin bonding immediately after bleaching. Group-C: resin bonding 1day after bleaching. Group-D: resin bonding 2 days after bleaching. Group-E: resin bonding 7days after bleaching. Shear bond strengths were measured with a cross-head speed of 1.0 mm/min using an Instron machine. The data of results were statistically analyzed by analysis of variance (ANOVA) and Tukey multiple comparison test. (P = .05) RESULTS: There were significant decreases in mean shear strength in immediately bonding group after bleaching. The reduction of bond strengths was 78% compared with the group of no bleaching treatment. Group C showed the recovery of 51%, and Group D showed recovery of 63%. Both of them have no statistical difference with non-bleaching group. Group E showed no statistical difference with no bleaching treatment group. CONCLUSION: Dentin bonding strength is significantly reduced when bonding is performed immediately after bleaching for in-office bleaching regimens using 35% hydrogen peroxide, and increases as time goes by. One week of elapsed time between bleaching and resin bonding significantly increases bonding strengths for the in-office bleaching technique.
Dental Enamel ; Dentin ; Humans ; Hydrogen Peroxide ; Molar, Third ; Peroxides ; Shear Strength ; Silicones ; Tooth

BACKGROUND/AIMS: Sacroiliitis (SI) is one of the most frequent extraintestinal manifestations in inflammatory bowel disease (IBD) patients, but the exact prevalence has not been evaluated in Asia. There are few data on the association between SI and other clinical features of IBD. The prevalence of SI was evaluated using computed tomography (CT) and the phenotypic parameters associated with SI in Korean IBD patients were determined. METHODS: Eighty-two patients with ulcerative colitis (UC) and 81 patients with Crohn's disease (CD) were evaluated clinically. The presence of SI was evaluated using bone window setting of abdomino-pelvic CT images by two radiologists. RESULTS: The prevalence rates of SI were 12.2% and 21.0% in the UC and CD groups, respectively. There was no relationship between the localization or extent of intestinal inflammation and the presence of SI in the UC group. Multivariate analyses confirmed that perianal and upper-gastrointestinal (from the mouth through to the jejunum) diseases were associated with the occurrence of SI in the CD group (p=0.026 and p=0.047, respectively). CONCLUSIONS: SI was as common among Korean IBD patients as among Western patients. Perianal or upper-gastrointestinal involvement is associated with SI in CD patients.
Asia ; Colitis, Ulcerative ; Crohn Disease ; Humans ; Inflammation ; Inflammatory Bowel Diseases ; Mouth ; Multivariate Analysis ; Prevalence ; Sacroiliitis