In Vitro Evaluation of the Effectiveness of Dental Bleaching with Carbamide Peroxide and Violet Light.

Objective: The aim of the current study was to use the CIELab system to evaluate the performance of the whitening treatment involving violet light-emitting diode (LED) combined with a home 10% and 22% carbamide peroxide dental bleaching technique on dental enamel. Methods: Fifty blocks of bovine dental enamel were divided into five groups: control group (control), receiving only LED irradiation; Whitening 10%, receiving 10% carbamide peroxide treatment; Whitening 10%+VL, receiving 10% carbamide peroxide treatment combined with LED irradiation; Whitening 22%, receiving 22% carbamide peroxide treatment; and Whitening 22%+VL, receiving 22% carbamide peroxide treatment combined with violet LED irradiation. Color tests were performed before the protocols, after 1 week and after 2 weeks of treatment by using a spectrophotometer and the CIELab parameters: L*, (a*) and (b*). The Whitening 10%, Whitening 10%+VL, Whitening 22% and Whitening 22%+VL groups were submitted to 10% and 22% carbamide peroxide 8 h per day for 14 days, whereas the Control was only stored in artificial saliva. For irradiation in the Control, Whitening 10%+VL, and Whitening 22%+VL groups, we used violet LED at a wavelength of 405-410 nm activated for 60 permanent seconds and 30 sec of pause once per week. As all data exhibited normal distribution, the comparisons were performed by using two-way repeated-measures analysis of variance. A post hoc t-test was employed, followed by the Ryan-Holm stepdown Bonferroni procedure. Results: After 1 week, the Whitening 22%+VL group differed significantly from all other groups in relation to hue, while no difference was found between the remaining groups (p < 0.05). Analyzing lightness, the Whitening 22%+VL and Whiteness10%+VL groups differed from the other groups (p > 0.05). In the 2nd week, the Whitening 22%+VL groups differed significantly from all other groups (p < 0.05) in hue, chroma, and lightness. The comparative analysis of bleaching times within the same group revealed significant differences in the Whitening 22%+VL group between baseline and week 1, baseline and week 2, as well as weeks 1 and 2 in terms of hue (p > 0.05). In the Whitening 22%+VL group, significant differences (p < 0.05) were found between baseline and week 2 as well as between weeks 1 and 2 in chroma (p > 0.05). In the Whitening 22%+VL group, statistically significant differences (p < 0.05) were found between baseline and week 1, baseline and week 2, as well as between weeks 1 and 2 in lightness. In the Whitening 10%+VL group, statistically significant differences (p < 0.05) were found between baseline and week 1, between baseline and week 2, as well as between weeks 1 and 2 in lightness. Conclusions: Tooth whitening treatment involving 10% and 22% carbamide peroxide combined with violet light promoted changes in the three axes of color (ΔH, ΔC, and ΔL) of the specimens evaluated. The use of the gel bleach alone was more efficient when the higher concentration was used. When violet light was combined with the gel, the lower concentration was more efficient.

Antimicrobial photodynamic chemotherapy mediated by PapaMBlue on chronic periodontal disease: Study protocol for a randomized, blind, controlled trial.

BACKGROUND: The elimination of the pathogenic microorganisms of the periodontal pocket is one of the main points for success in periodontal treatment. The objective of this study is to investigate the clinical and antimicrobial effect of papain-mediated photodynamic therapy in the clinical treatment of periodontal disease. METHODS: Twenty patients with chronic periodontitis will be selected. Patients will be randomly divided into 2 groups (n = 10). Group 1 will receive conventional periodontal treatment and group 2 will receive conventional treatment and antimicrobial photodynamic therapy (PACT). Conventional treatment will consist of oral hygiene guidance, with brushing technique instructions and recommendation of daily flossing. The calculus deposits on the teeth will be removed with ultrasound equipment and curettes for scraping and root planning. The PACT will be performed at the end of each periodontal treatment session, at sites with bags ≥4 mm. PapaMblue photosensitizer will be deposited in the periodontal pockets with a syringe and a pre-irradiation time of 1 minute will be adopted. Then, the laser emitting wavelength of 660 nm, with power of 100 mW, for 2 minutes, radiant exposure of 30 J/cm and power density of 250 mW/cm will be applied. Patients will undergo clinical evaluations before treatment (day 1) at 30, 60, and 90 days after the end of treatment; and microbiological evaluations before and immediately after treatment. The distribution of the data within each group and the homogeneity of the variances will be verified. With this information, the most appropriate statistical test in each evaluation will be used. The sample calculation is based on the literature and the significance level of 5% will be adopted. DISCUSSION: The combination of PACT with methylene blue in a papain gel and the conventional treatment may increase the reduction of bacteria in periodontal pockets.

Evaluation of Different Dentifrice Compositions for Increasing the Hardness of Demineralized Enamel: An in Vitro Study.

This study aimed to evaluate microhardness of a dentifrice containing fluoride and arginine compared to a positive control (fluoride only) and a negative control (no fluoride) on sound and demineralized bovine enamel surfaces. Specimens were randomly assigned to different treatments that included daily pH cycling and brushing three times a day with one of the following dentifrices (n = 8): Neutraçucar (arginine and fluoride), Colgate Total 12 (fluoride) and My First Colgate (no fluoride). Enamel carious lesions were artificially created one week before the beginning of these treatments (demineralized bovine enamel (DE) groups). The same groups were also tested in sound enamel (sound bovine enamel (SE) groups). Microhardness was measured at baseline and after one, two, and five weeks of treatment using a Knoop indenter. Statistical analysis involved two-way Analysis of Variance (ANOVA) and Tukey's test. After five weeks, both Total 12 and Neutraçucar had increased the microhardness of DE specimens (p < 0.05). Only Neutraçucar had increased the microhardness of the sound enamel after five weeks of treatment. Thus, it could be concluded that arginine-based dentifrices increase the microhardness of sound and demineralized bovine enamel surfaces.

Microhardness of bovine enamel after different fluoride application protocols.

The aim of the present study was to evaluate microhardness, mineral recovery and the enamel surface after the application of topical fluoride to artificial dental caries. Twenty-five bovine enamel blocks were prepared for artificial caries-like lesions and randomly divided into five groups (n=5): untreated (C control), 1.23% acidulated phosphate fluoride gel (APG), 2% neutral fluoride gel (NFG), 1.23% acidulated fluoride mousse (AFM) and fluoride varnish (5% Duraphat, DFV). Knoop microhardness (KHN) was evaluated after 7 and 14 days of treatment as well as 1 week after 28 days of treatment. Electron and confocal microscopy and energy dispersive spectroscopy were performed. KHN data were treated with two-way ANOVA (material×time) and Tukey's test at a 5% significance level. Differences were found among groups over time (p<0.001). Microhardness varied after 7 and 14 days of treatment and remained stable 1 week after 28 days of treatment. Mineral recovery and enamel topography varied among groups, with the fluoride varnish achieving the most uniform topography.

Influence of Ultrapulsed CO2 Laser, before Application of Different Types of Fluoride, on the Increase of Microhardness of Enamel In Vitro.

OBJECTIVE: To evaluate the influence of ultrapulsed CO2 laser in combination with commercial fluoride products in order to verify the increase of microhardness of artificial enamel caries lesions. MATERIALS AND METHODS: Bovine enamel specimens were prepared, and artificial enamel caries lesions were created. Teeth were randomly divided into 5 groups (n=10): treated with laser (L), laser + neutral fluoride gel 2% (LNF), laser + acidulated phosphate fluoride gel 1.23% (LAFG), laser + acidulated fluoride mousse 1.23% (LAFM), and laser + fluoride varnish 5% (LFV). Microhardness was evaluated at baseline, after caries induction, after CO2 laser irradiation + fluoride treatment in the 1st week, and after fluoride treatment at 3rd and 5th week. RESULTS: There was a decrease in microhardness in all groups after artificial enamel caries lesion formation; no increase in microhardness was found in the first and third weeks in all groups (p > 0.05). In the fifth week, an increase in microhardness occurred in all groups (p < 0.05). CONCLUSION: Although CO2 laser irradiation in combination with different commercial fluoride products was capable of increasing microhardness on enamel caries lesions in bovine tooth enamel it is necessary to confirm these results by testing the isolated effect of fluoride on enamel surface microhardness. Also, although microhardness was higher in the fluoride varnish group than in the other groups in the fifth week it is not possible to discard the best effect of fluoride varnish treatment on absence of artifacts that may occur with the other fluoride treatments. CLINICAL RELEVANCE: In order to prove that CO2 laser may contribute to an increase in microhardness when applied to enamel lesions in combination with different commercial fluoride products it is necessary to conduct additional studies. Also, higher microhardness of fluoride varnish group should be carefully considered.