Influence Of Surface Treatments On Enamel Susceptibility To Staining By Cigarette Smoke.

The purpose of this study was to evaluate the influence of remineralizing agents, including artificial saliva, neutral fluoride, and casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), on the susceptibility of bleached enamel to staining by cigarette smoke. Fifty bovine enamel blocks were randomly divided into five groups (n = 10): G1- bleaching; G2- bleaching and immersion in artificial saliva; G3- bleaching and application of CPP-ACP; G4- bleaching and application of neutral fluoride; and G5- untreated (Control). Teeth were bleached with 35% hydrogen peroxide and treated with the appropriate remineralizing agent. After treatment, all groups were exposed to cigarette smoke. Enamel color measurements were performed at three different times: before treatment (T1), after treatment (bleaching and remineralizing agent) (T2), and after staining (T3), by using the CIE Lab method with a spectrophotometer. The data coordinate L* was evaluated by analysis of repeated-measures PROC MIXED and Tukey-Kramer's test, and the ΔE values were submitted to one-way ANOVA and Tukey's test (α = 0.05). The G1 group did not show any statistically significant difference for L* values between times T1 and T2. The G4 and G5 groups showed lower L* values at T3 compared to T2. No significant differences between the groups were observed for ΔE (after treatment and staining). However, G4 showed a clinically apparent color change. Treatment of bleached enamel with neutral fluoride can contribute to the increased staining of enamel due to cigarette smoke. Key words:Spectrophotometer, remineralizing agents, bleaching.5e163-

Effectiveness Of Dental Bleaching In Depth After Using Different Bleaching Agents.

This study evaluated the effectiveness of low- and high-concentration bleaching agents on enamel and deep dentin. Stained bovine incisors fragments were randomized placed into 10 groups (n=5), according to the sample thicknesses (2.0 mm or 3.5 mm) and bleaching agent: 10% carbamide peroxide (CP) (4 h a day/21 days); 6% hydrogen peroxide (HP) with calcium (1:30 h a day/21 days); HP 20% with calcium (50 min a day/3 sessions with a 7-day interval); HP 35% (3 x 15 min a day/3 sessions with a 7-day interval); HP 35% with calcium (40 min a day/3 sessions with a 7-day interval). The samples were stored in artificial saliva during the experiment. The color change was evaluated using a spectrophotometer at the initial analysis, after artificially staining with black tea and after each of the bleaching weeks, and data was expressed in CIE Lab System values. The L* coordinate data was submitted to analysis of variance and Tukey-Kramer test and the ?E values data was submitted for analysis of variance in a split-plot ANOVA and Tukey's test (?=0.05). None of the bleaching agents tested differed from the reflectance values on the enamel surface. For deep dentin HP 20% and HP 35%, both with calcium, showed the lowest reflectance values, which differed from CP 10%. It is concluded that high concentration hydrogen peroxide with calcium was less effective in deep dentin than 10% carbamide peroxide. Key words:Dental bleaching; hydrogen peroxide; carbamide peroxide; dental staining.5e100-

Surface finishing of glass ionomer

Purpose: To evaluate the surface roughness and staining of a glass ionomer cement when subjected to different finishing procedures. Materials and Methods: Sixty-four discs of Chem-Fil II glass ionomer cement were submitted to staining test with methylene blue by spectrophotometry and roughness test by profilometry. Four groups were evaluated: Mylar matrix (control), Sof-Lex discs, Enhance points, and diamond bur. Results: Staining and roughness test, analyzed by ANOVA and Tukey's test, showed that the best surface was obtained when the material cured in contact with the Mylar matrix strip or when treated with Sof-Lex discs. The poorest results were obtained after using the diamond bur

Enamel Morphology After Microabrasion With Experimental Compounds.

Enamel microabrasion is an esthetic treatment for removing superficial stains or defects of enamel. This study evaluated the roughness after enamel microabrasion using experimental microabrasive systems. One hundred and ten samples (5 × 5 mm) were obtained from bovine incisors and divided into 11 groups (n = 10) in accordance with the treatment: Microabrasion using 6.6% hydrochloric acid (HCl) or 35% phosphoric acid (H3PO4) associated with aluminum oxide (AlO3) or pumice (Pum) with active application (using rubber cup coupled with a micro-motor of low rotation) or passive application (just placing the mixture on the enamel surface); just the use of acids in a passive application (negative control), and a group without treatment (positive control). Roughness analysis was performed before and after treatments. The statistical analysis used analysis of variance (PROC MIXED), Tukey-Kramer and Dunnet tests (P < 0.05). Representative specimens were evaluated using scanning electron microscopy (SEM). There was no significant difference between the acids used (P = 0.0510) and the applications (P = 0.8989). All of the treated groups were statistically different from the positive control. When using passive application, the use of HCl + AlO3 resulted in higher roughness when compared with HCl + Pum. Additionally, this treatment was statistically different from the passive application of H3PO4 (negative control) (P < 0.05). However, SEM analysis showed that the treatment with AlO3 resulted in an enamel surface with a more polished aspect when compared with Pum. AlO3 may be a suitable particle for use in microabrasive systems.6170-17

Efficacy Of Tooth Bleaching With The Prior Application Of A Desensitizing Agent.

In the present study, we evaluated the efficacy of bleaching on enamel and opposite dentin surfaces using 35% hydrogen peroxide (HP) with the prior application of a desensitizing agent. Thirty bovine dental fragments, with thicknesses of 1 mm enamel and 1.75 mm dentin, were stained in a solution of black tea. The fragments were randomly divided into three groups (n = 10) according to the following protocols: (a) 2% neutral fluoride + bleaching; (b) desensitizing agent + bleaching; and (c) without desensitizer + bleaching. The bleaching efficacy was evaluated four times: after staining with tea (baseline) and after each of the 3 weeks of bleaching, by means of the CIE Lab method using a reflectance spectrophotometer. The data coordinate L* was evaluated by an analysis of repeated measures with PROC MIXED and Tukey-Kramer's test. The ΔE values were subjected to anova and Tukey's test (α = 0.05). The 35% HP treatment showed greater efficacy on deep dentin after removal of the enamel stains, with increasing means during all times in all treatments. The use of a desensitizing agent prior to the bleaching session did not affect the mechanism of action of 35% HP with regard to tooth depth