ABSTRACT
AIM: The aim of this study was to evaluate the shear bond strength (SBS) of self-adhering flowable composites on the dentinal surface prepared with carbide and diamond burs. MATERIALS AND METHODS: A total of 64 extracted mandibular molars were mounted on acrylic resin blocks, and the coronal part of the dentin was exposed and polished. Then, they were divided into Group 1 and Group 2 for carbide and diamond bur preparation, respectively. Two teeth in each group were evaluated under scanning electron microscope, ×500, to view the surface changes following the bur preparation. The remaining teeth were subdivided into Groups A, B, and C to be restored with Constic, Dyad™-flow, and Tetric N Flow composites, respectively. Then, the specimens were stored in distilled water at 37°C for 24 h, and then subjected to universal testing machine to evaluate the SBS and viewed under light stereomicroscope to evaluate the type of failure. STATISTICAL ANALYSIS: SPSS version 22 (IBM Corp) for Windows was used for statistical analysis. The values were subjected to ANOVA followed by Bonferroni post hoc analysis. The values between the groups were analyzed using Student's unpaired t-test. RESULTS: Statistically significant differences in the SBS values were seen between Groups A and C (P < 0.001) and Groups B and C (P < 0.001). Statistically significant differences were seen in SBS values of Dyad-flow (Group B) (P < 0.004) and Tetric N flow (P < 0.007) for surfaces prepared with carbide and diamond burs. CONCLUSION: It was concluded that the SBS of Tetric-N Flow was higher than that of the experimental groups of Constic and Dyad-flow. Dentinal surface preparation with carbide bur resulted in higher SBS for Tetric N Flow and Dyad-flow but not for Constic.
ABSTRACT
The aim of this clinical trial was to compare tooth sensitivity during and after bleaching with hydrogen peroxide gel following application of GLUMA Desensitizer PowerGel or placebo. Forty-six subjects with sound maxillary incisors and canines were enrolled. Tooth shades were determined by comparison with a Vitapan Classic Shade guide. GLUMA Desensitizer PowerGel and placebo were randomly applied to the labial surfaces of the left or right anterior teeth for 1 min, which were then rinsed and dried. Then, Opalescence Boost PF 40% gel was applied onto labial enamel for 15 min. Sensitivity scores [recorded on a 10-point visual-analog scale (VAS)] were determined before, at 5, 10, and 15 min during, and 1, 24, 48 h and 1 wk after, the bleaching treatment. Shades were determined postbleaching and after 1 wk. Prebleaching application of GLUMA Desensitizer PowerGel significantly reduced tooth sensitivity during and after bleaching when compared with treatment with placebo. The whitening effects immediately and 1 wk after bleaching were significant when compared with the prebleaching shades. In conclusion, tooth pretreatment with GLUMA Desensitizer PowerGel for 1 min prior to 15 min of in-office bleaching with 40% hydrogen peroxide gel was highly effective in reducing tooth sensitivity during and after bleaching.
