Correlation between patient satisfaction and color changes after tooth bleaching.

OBJECTIVE: This study aimed to investigate the relationship between patient satisfaction of outcomes and tooth color changes during and after tooth bleaching. METHODS: In this clinical trial, 63 volunteers participated in an in-office bleaching procedure using a 40% hydrogen peroxide gel. The treatment consisted of two sessions, each comprising two 30-min applications of the bleaching gel. The L*, a*, and b* values of six maxillary anterior teeth were measured at baseline (T1), after the first bleaching session (T2), after the second bleaching session (T3), 1 week after the second in-office bleaching session (T4), and 3 weeks after the second in-office bleaching session (T5). The color differences (ΔE00 ) were calculated using CIEDE2000. A satisfaction scale with a score ranging from 0 to 3 was used to record participants' level of satisfaction with their tooth color at each time point. The data were statistically analyzed using repeated measures analysis of variance and logistic regression (α = 0.05). RESULTS: Significant correlations were observed between ΔL*, Δb*, and ΔE00 values at T3 and patient satisfaction (all p < 0.05). The regression model indicated a more pronounced impact of Δb* on patient satisfaction compared to ΔL*. The established regression models were as follows: Logit (PL*b* ) = -4.354 + 0.271ΔL* - 0.585Δb* and Logit (PΔE00 ) = -2.552 + 0.521ΔE00 . The findings suggested a minimum ΔE00 value of 4.90 for satisfactory results. A minimum ΔE00 value of 3.9, 5.0, and 6.8 was necessary for central incisors, lateral incisors, and canines, respectively, to achieve a satisfactory result. CONCLUSIONS: The ΔL*, Δb*, and ΔE00 values were found to be significantly correlated with patient satisfaction after bleaching. Δb* was identified as having a greater influence on patient satisfaction than ΔL* values in the regression model. Furthermore, attaining a minimum ΔE00 value of 4.90 is necessary to achieve satisfactory outcomes. A greater ΔE00 value is needed for canines than for incisors to achieve equivalent patient satisfaction. CLINICAL SIGNIFICANCE: This study emphasizes the importance of considering the extent of color change needed to achieve patient satisfaction after tooth bleaching procedures.

Effects of the application timing of anti-erosive agents on dentin erosion.

This in vitro study aimed to evaluate the effects of the application timing of anti-erosive agents on dentin erosion. Eighty dentin specimens with dimensions of 2 × 2 × 2 mm were prepared and randomly divided into 4 groups based on the treatment solutions: 1.23 × 104 µg/ml sodium fluoride (NaF), 120 µg/ml chlorhexidine (CHX), 300 µg/ml quercetin (QUE), and deionized water (DW, negative control). The specimens in each group were further divided into 2 subgroups according to the application timing of the treatment solutions (n = 10): before the erosive challenges (PRE) and after the erosive challenges (POST). All specimens were submitted to 4 daily erosive challenges for 5 d. For each erosive challenge, the specimens in the subgroup PRE were treated with the respective solutions for 2 min and then immersed in cola drinks for 5 min, while the specimens in the subgroup POST were immersed in cola drinks for 5 min followed by treatment with the respective solutions for 2 min. The erosive dentin loss (EDL) was measured using a contact profilometer, and the surface morphology of the dentin specimens was evaluated by scanning electron microscopy at the end of the experiment. The data were statistically analyzed using two-way analysis of variance (ANOVA) and Bonferroni's test (α = 0.05). Significantly less EDL was observed in the groups NaF, CHX, and QUE than in the group DW (all P < 0.001). Significantly lower EDL was observed in the groups CHX and QUE than in the group NaF (P = 0.001 and P < 0.001, respectively). For CHX, subgroup POST exhibited significantly less EDL than subgroup PRE (P < 0.001). Regarding QUE, subgroup PRE showed significantly less EDL than subgroup POST (P < 0.001). Furthermore, a relatively greater number of obliterated dentinal tubules was visible in the subgroup POST rather than in the subgroup PRE of the group CHX, while in the group QUE, narrower dentinal tubules were observed in the subgroup PRE than those in subgroup POST. In conclusion, CHX and QUE showed the best performance in controlling dentin erosion. CHX was more effective in reducing EDL when applied after erosive challenges, whereas QUE worked more effectively when used before erosive attacks. The application timing should be considered when evaluating the effects of anti-erosive agents because it may determine their effectiveness.