Colour assessment using digital methods can yield varying results, and it is important for clinicians to recognize the potential variability intra and inter-device. This study aimed to compare the L*a*b* values of VITA Classical (VC) and VITA Toothguide 3D-MASTER (VM) guides using two methods, SpectroShade (SS) and eLAB. Thirty-four measurements per tab were performed by a single operator across three batches of each guide. Intraclass correlation coefficients (ICC) between batches were calculated. Values 0.90 were classified as poor, moderate, good, and excellent reliability, respectively. Results were reported as mean and standard deviation of the L*a*b* values and respective colour differences (ΔE₀₀) for each tab and method. Statistical analyses were performed with an independent t-test, α = 0.05. ICC values between batches were excellent for all L*a*b*, except for a* component in eLAB. There were statistically significant differences between methods in most L*a*b* values. The intra-device mean ΔE₀₀ was 0.5 ± 0.6 for VC, 0.5 ± 0.8 for VM in SS, 1.1 ± 0.8 for VC, 1.1 ± 0.9 for VM in eLAB. The mean ΔE₀₀ inter-device was 4.9 ± 1.7 for VC, 5.0 ± 1.7 for VM. Both methods demonstrated good internal consistency, with high ICC values and low intra-device colour differences, but exhibited high variability between methods, higher for a* the component.

Tooth whitening efficacy can be influenced by several factors, of which concentration and application time are two of the most important. This in vitro study aimed to evaluate the initial content and release kinetics of the hydrogen peroxide (HP) content, or the carbamide peroxide (CP) content as converted to its HP equivalent, of four tooth whitening products with different concentrations (6% HP, 16% CP, 10% CP, and 5% CP). Titrations with Cerium Sulphate IV were performed to determine HP concentration. HP release kinetics were evaluated by a spectrophotometric technique. The results were expressed as the mean values and 95% confidence interval of the percentage of hydrogen peroxide content during release kinetics. One sample t-test, one-way ANOVA, Tukey post hoc testing, and Pearson correlation testing were used, as appropriate, with a significance level of α = 0.05. The concentration of titrated HP was higher than that indicated by the manufacturers in all tested products (p < 0.01). At the minimum application times indicated by the manufacturers, all products released at least 85% of HP content; the gel containing 10% CP registered the lowest release at 85.49 (81.52–89.46). There was a significant HP release in all products during the application times indicated by the manufacturers. Further studies are needed to assess in vitro release kinetics.

Whitening products commonly utilize hydrogen peroxide (HP) as an active principle, which can penetrate dental tissues with potential side effects due to its low molecular weight. This study aimed to evaluate the HP diffusion of two in-office whitening products, namely 6% VivaStyle Paint On Plus (VS) and Opalescence Boost 40% (OP), in different tooth types. Additionally, the influence of the area of exposure, dental tissue thickness and pulp chamber volume was assessed. Each group consisted of eighteen intact anterior (A), premolar (PM) and molar (M) human teeth, and a positive pulpal pressure model was employed. The samples were analyzed using spectrophotometry, and results were expressed as the mean and 95% confidence interval. Statistical tests and linear regression models were appropriately applied at α = 5%. The total HP (µg) retrieved was as follows: VS-A, 1.333 [1.214, 1.452]; OP-A, 1.538 [1.457, 1.620]; VS-PM, 1.208 [1.123, 1.291]; OP-PM, 3.628 [3.401, 3.855]; VS-M, 2.560 [2.297, 2.823]; and OP-M, 4.197 [3.997, 4.396], with statistically significant differences in diffusion kinetics between whitening products for PM and M. Several HP concentrations attained a minimum cytotoxicity value of 2.22 µg/mL. The regression model shows that OP exposed the pulp chamber to 1.421 µg of HP more than that of VS. Different whitening products can cause cytotoxic HP concentrations in the pulp chamber, with a higher risk observed in molars.

Objectives: To evaluate the tooth bleaching effectiveness of a 6% hydrogen peroxide paint-on varnish with two different types of soft-tissue protection materials. Methods: Twenty patients were screened according to inclusion and exclusion criteria, submitted to professional dental prophylaxis, and randomly allocated to one of the two groups. An in-office bleaching technique protocol was performed (VivaStyle Paint On Plus, Ivoclar-Vivadent (R), Liechtenstein) with two different soft-tissue protection materials: Group 1-Vase-line; Group 2 - block-out resin. Bleaching effectiveness was evaluated with Delta E-00 and Delta WID, calculated from the CIE L*a*b* values obtained by spectrophotometry analysis (SpectroShade). Appropriate statistical tests were performed to analyze intragroup differences in CIE L*a*b* and WI D values and intergroup differences in Delta E-00 and Delta WID with alpha=0.05. Results: Both groups presented statistically significant (P 1.8; Delta WID > 2.60), and the Delta WID was mostly classified as hardly acceptable differences. Group 2 presented higher statistically significant (P<0.01) mean values with Delta E-00 = 3.5 +/- 1.5 and Delta WID = 8.6 +/- 4.2. Conclusions:The 6% hydrogen peroxide paint-on varnish tooth bleaching technique showed clinical effectiveness. However, effectiveness varied with the soft-tissue protection material used, with better results when applying a block-out resin, thus suggesting its clinical recommendation. (C) 2021 Sociedade Portuguesa de Estomatologia e Medicina Dentaria. Published by SPEMD.