Which whitening toothpaste with different contents is more effective on color and bond strength of enamel?

OBJECTIVE: To evaluate the effects of six whitening toothpastes with different whitening ingredients as follows: abrasives, polyphosphates, activated charcoal and hydrogen peroxide on the color, and shear bond strength (SBS) of enamel. MATERIALS AND METHODS: Thirty-five extracted human molars were sectioned in mesiodistal direction, providing 70 enamel specimens and randomly divided into seven groups having different whitening ingredients (n = 10). After baseline color measurements, the specimens were brushed three times daily for the 30 s. At the end of 2 weeks, spectrophotometric readings were repeated, and color change parameters were calculated. Then, composite cylinders were built on the enamel surfaces and the specimens were subjected to SBS test. Failure modes were determined under a stereomicroscope (×10). One specimen from each group was examined with scanning electron microscope (SEM). The data were statistically analyzed using Kruskal-Wallis, Wilcoxon signed, one-way-ANOVA (p = 0.05). RESULTS: Clinically acceptable color change was observed in all whitening toothpastes. There were no significant differences among the groups for Δa, ΔL, ΔE00 , and ΔWID (p > 0.05). The differences among the groups were not significant regarding SBS and failure mode distributions (p > 0.05). SEM findings were in line with the SBS test and failure mode distribution results. CONCLUSIONS: All the tested whitening toothpastes showed similar and clinically acceptable efficacy on the color change of the enamel and led to comparable SBS values. CLINICAL SIGNIFICANCE: The tested whitening toothpastes had an acceptable whitening efficacy and did not have a negative effect on the bond strength to the enamel.

Clinical Performance of a "No Wait" Universal Adhesive in Noncarious Cervical Lesions: A Two-year Randomized Controlled Clinical Trial.

PURPOSE: To evaluate the 24-month clinical performance of a "no wait" universal adhesive with different application modes in comparison with an etch-and-rinsew and two-step self-etch adhesive in non-carious cervical lesions (NCCLs). MATERIALS AND METHODS: A total of 234 non-carious cervical lesions in 34 patients were restored following 5 different adhesive approaches: 1. Clearfil Universal Bond Quick, self-etch mode (CUQ-SE); 2. Clearfil Universal Bond Quick, selective etch mode (CUQ-SLE); 3. Clearfil Universal Bond Quick, etch-and-rinse mode (CUQ-ER); 4. Clearfil SE Bond (self-etch adhesive) (CSEB); 5. Tetric N-Bond Universal, etch-and-rinse mode (TBU-ER). All NCCLs were restored with a nanohybrid composite (Tetric N-Ceram). The restorations were evaluated at baseline, 6, 12, and 24months of clinical service regarding retention, marginal adaptation, marginal discoloration, secondary caries, post-operative sensitivity, color match, surface texture using modified United States Public Health Service (USPHS) criteria. RESULTS: The patient recall rate at 24 months was 73.5%. Eleven restorations, 6 of the CUQ-SE group, 4 of the CSEB group and 1 of the TBU-ER group, were clinically unacceptable due to retention loss. Regarding marginal adaptation and discoloration, CUQ-SE and CSEB groups exhibited higher bravo scores than other groups after 24 months (p < 0.05). At the end of 24-month examinations, no significant differences were detected among the groups regarding secondary caries, post-operative sensitivity, color match and surface texture. CONCLUSION: The clinical survival rates of the "no wait" universal adhesive at self-etch mode after 24 months were not acceptable. The "no wait" universal adhesive showed clinically acceptable performance in selective-etch and etch-and-rinse mode according to the evaluated USPHS criteria.