Effects of Bleaching Agents Combined with Regular and Whitening Toothpastes on Surface Roughness and Mineral Content of Enamel.

OBJECTIVE: The purpose of this study was to evaluate surface roughness and changes in the composition of enamel submitted to different bleaching protocols and toothbrushing with regular and whitening toothpastes. BACKGROUND DATA: Bleaching treatment could promote morphological and chemical changes in enamel surface. METHODS: Enamel blocks were randomized into nine groups (n=10) according to the bleaching treatment (no bleaching, control group; 6% hydrogen peroxide, HP; or 10% carbamide peroxide, CP) and toothpaste used (placebo, PL; regular, R; or whitening dentifrice, W). Bleaching was performed according to manufacturers' instructions and all groups were submitted to 30,000 cycles of simulated toothbrushing with toothpaste (PL, R, or W). Mineral content evaluation and enamel roughness were evaluated initially (T1), after bleaching (T2), and after toothbrushing (T3), using an energy-dispersive micro X-ray fluorescence spectrometer and profilometry, respectively. Data were statistically analyzed with two way ANOVA, Tukey, and Dunnett tests (5%). RESULTS: Enamel surface roughness was influenced by bleaching and toothbrushing. Surface roughness increased for the groups that brushed with the placebo dentifrice (CP+PL, HP+PL, C+PL) and for the control group that brushed with whitening dentifrice (C+W). Enamel Ca/P ratio decreased after bleaching, but toothbrushing, regardless of the dentifrice used, did not reduce the enamel mineral content. CONCLUSIONS: The bleaching treatment resulted in a decrease of enamel mineral content, but the studied dentifrices did not contribute to surface mineral loss.

Antimicrobial effects of ozonated water on the sanitization of dental instruments contaminated with E. coli, S. aureus, C. albicans, or the spores of B. atrophaeus.

OBJECTIVES: Ozone has been used as an alternative method for the decontamination of water, food, equipment and instruments. The objective of this study was to evaluate the antimicrobial effects of ozonated water on the sanitization of dental instruments that were contaminated by Escherichia coli, Staphylococcus aureus, Candida albicans and the spores of Bacillus atrophaeus. METHODS: A total of one hundred and twenty standardized samples of diamond dental burs were experimentally contaminated with E. coli (ATCC 25922), S. aureus (ATCC 6538) and C. albicans (ATCC 18804) and the spores of B. atrophaeus (ATCC 6633) for 30 min. After the contamination, the samples were exposed to ozonated water (10mg/L O(3)) for 10 or 30min. The control group was composed of samples that were exposed to distilled water for 30 min. After the exposure to the ozonated water, 0.1 mL aliquots were seeded onto BHI agar to count the colony-forming units per milliliter (CFU/mL) of E. coli, S. aureus, and B. atrophaeus. Sabouraud dextrose agar was used to count the CFU/mL of C. albicans. The results were subjected to an analysis of variance and the Tukey test. RESULTS: For all of the microorganisms studied, the ozonated water reduced the number of CFU/mL after 10 and 30 min of sanitization, and this microbial reduction was dependent on the duration of the exposure to the ozonated water. E. coli exhibited the greatest reduction in CFU/mL (2.72-3.78 log) followed by S. aureus (2.14-3.19 log), C. albicans (1.44-2.14 log) and the spores of B. atrophaeus (1.01-1.98 log). CONCLUSION: The ozonated water was effective in reducing the CFU of E. coli, S. aureus, C. albicans and B. atrophaeus spores, suggesting that ozonated water can be used for the sanitization of dental instruments.

Influence of saliva contamination on the shear bond strength of orthodontic brackets bonded with self-etching adhesive systems.

INTRODUCTION: Our objective was to evaluate the influence of saliva contamination on the shear bond strength of orthodontic brackets bonded with self-etching primers. METHODS: One hundred thirty-five bovine incisors were randomly divided into 3 groups, and exposed enamel surfaces were bonded with Transbond Plus Self Etching Primer (TB) (3M Unitek, Monrovia, Calif), Adhese Single Bottle (AD) (Ivoclar, Vivadent, Schaan, Liechtenstein), and Self Etch Bond (SE) (Vigodent, Rio de Janeiro, Brazil). Each group was subdivided into 3 treatments (n = 15): saliva contamination (S), saliva contamination and deionized water rinsing (SW), and no salivary contamination (C). Resin composite (Z-100, 3M/ESPE, Salt Lake City, Utah) was applied to all samples to bond the orthodontic brackets. Shear bond strength testing was carried out in a universal testing machine operating at 1.0 mm per minute. RESULTS: The results were statistically analyzed with 2-way analysis of variance (ANOVA) and Tukey tests (P <0.05). Saliva contamination caused a significant decrease of enamel strength in the groups bonded with TB and SE compared with the SW and C groups. Enamel bond strengths of the C and SW groups were higher than those of the TB group, followed by the AD and SE groups. Enamel bond strength after S was higher than AD, followed by TB and SE. CONCLUSIONS: The shear bond strengths of orthodontic brackets to enamel and the performance of the adhesive systems were influenced by contamination with saliva.

Effects of 10% carbamide peroxide treatment and sodium fluoride therapies on human enamel surface microhardness.

This study sought to evaluate the microhardness of enamel submitted to 10% carbamide peroxide treatment and different methods of remineralization involving sodium fluoride (NaF). Non-erupted third molars were used and 75 enamel blocks with standardized dimensions (4.0 x 4.0 x 2.0 mm) were obtained. Enamel blocks were randomly divided into five groups (n = 15): one control (no bleaching and no fluoride treatment), one receiving a 10% carbamide peroxide treatment, one receiving 10% carbamide peroxide plus acidulated phosphate fluoride, one receiving 10% carbamide peroxide with 0.2% NaF, and one receiving 10% carbamide peroxide and 0.05% NaF. There were no differences among four of the groups (p > 0.05); the group receiving 10% carbamide peroxide only was different from all other groups (p < 0.05). Based on these results, NaF therapies are recommended during carbamide peroxide bleaching treatments.

Analysis of photoreflectance and microhardness of the enamel in primary teeth submitted to different bleaching agents.

Treatment of darkened teeth in children is of great importance from an esthetic-functional point of view and for the psychoemotional development of the child. The objective of the present study was to determine the in vitro efficacy of three bleaching agents for whitening of artificially stained primary teeth. Fifty anterior primary teeth were artificially stained and then divided into three experimental groups (n = 15) submitted to bleaching treatment with 35% hydrogen peroxide gel, 35% carbamide peroxide gel, and 35% carbamide peroxide gel mixed with sodium perborate powder. The control group (n = 5) was not submitted to any bleaching treatment. Color changes were evaluated with a reflectance spectrophotometer and possible alterations in the enamel surface after bleaching were measured by Vickers microhardness testing. The data were assessed using the Student's t test. The results confirmed the bleaching action of the three agents tested. No significant difference in mean microhardness was observed between the three bleaching agents when compared to the control group.

Esthetic alternative for fluorosis blemishes with the usage of a dual bleaching system based on hydrogen peroxide at 35%.

Esthetic dental procedures in pediatric dentistry represent sources of satisfaction and realization, as much for the patient as for the professional. Lack of dental esthetics may develop psychological problems in infant as well as in adolescent patients. Blemishes produced by fluorosis appear as a challenge to the pediatric dentist and alternatives for treatment are desired. The scope of this present paper is to relate a clinical case with esthetic solution for blemishes in teeth enamel due to fluorosis. A dual system of bleaching was used (photo/chemically activated) based on hydrogen peroxide at 35% (Hi-Lite-Shofu) in a male eight-year-old patient with white fluorosis blemishes on teeth 11 and 21. The bleaching system used was efficient in bleaching teeth with white blemishes due to fluorosis, thus masking the blemishes and providing a more uniform appearance.

Human enamel veneer restoration in a deciduous tooth: clinical case.

Trauma to deciduous anterior teeth, frequently occur in children, and the treatment is a big challenge for the pediatric dentistry. In these cases, besides the pain and discomfort provoked by the injury, both child and parents/persons responsible were eager to reconstruct the damage, as soon as possible. In modern operative restorative dentistry, no restorative material is able to substitute for the human dental enamel in quality, color and resistance. The aim of this paper is to relate the treatment of esthetic veneer (facet) of human dental enamel in a three-year-old child after trauma that caused concussion and accentuated color alteration. Clinical results showed an efficient esthetical resolution, revealing it to be a good alternative for treatment of traumatized anterior deciduous teeth.

Effects of oral environment stabilization procedures on counts of Candida spp. in children.

The effects of oral environment stabilization procedures on counts of Candida spp. have rarely been discussed, and no conclusive results are found in the literature. The aim of this study was thus to ascertain the effects of oral environment stabilization procedures with glass ionomer and zinc oxide-eugenol cements on counts of Candida spp. in the oral cavity of children. For this purpose, oral rinses of sterile phosphate-buffered saline were initially collected from 30 boys and 30 girls, positive for Candida in the saliva and aged from 4 to 10 years. Data on the initial quantity of CFU/ml of Candida were obtained. Then, the children were randomly divided into two groups and oral environment stabilization procedures were performed using zinc oxide-eugenol cement or glass ionomer cement. One week after the procedures were performed, oral rinses were collected again and final Candida counts were obtained. An expressive reduction in Candida counts was observed in both groups. The zinc oxide-eugenol and glass ionomer cements were efficient in the reduction of Candida counts and statistically significant differences were observed between initial and final counts in both groups. Considering the percentage of reduction, the zinc oxide-eugenol cement presented more favorable results, with a reduction of 70%. A reduction of 46% was observed with the use of the glass ionomer cement. According to the obtained results, we concluded that oral environment stabilization procedures were efficient in reducing Candida spp. counts, especially when the zinc oxide-eugenol cement was employed.