More Articles  :

1. Bleaching of vital teeth through photosensitive agents
Journal of Applied Oral Science, vol.12 no.spe Bauru 2004
Author(s); Azevedo, J.F.D.G. de; Coneglian, E.A.C.; Asenjo-Martinez, M.A.J.; Mondelli, R.F.L.
Abstract
With emphasis on an aesthetic dentistry, there was, in the last decade, a marked evolution in dental bleaching due to the introduction of new bleaching agents and equipments that present new techniques, formulations, concentrations of the bleaching agent and varied light sources for the agents' activation. The purpose of this literature review is to evaluate the different activation forms for the photosensitive agents utilized in the bleaching of vital teeth in the clinic and its probable effect on the dental structures and adjacent tissues. Seven light apparatuses will be described with the specific bleaching function: the sources of halogen light; plasma arch with xenon lamp; LED associated with the diode laser; argon laser and diode laser, by comparing among them the wavelength, potency density, irradiance, type of light generating unit and time of application recommended by the manufacturer. As an illustration, a clinical case will be described, demonstrating the clinical bleaching technique in a single session, using the LED light source associated with the diode laser (Whitening Lase–DMC Equipamentos), and 35% hydrogen peroxide as a photosensitive agent (Whiteness HP – FGM Produtos Odontológicos
DMC Products used: Whitening Lase

3. Evaluation of wear and superficial roughness of bovine enamel submitted to bleaching and simulated brushing
Master’s Dissertation, Bauru School of Dentistry, date of thesis presentation: May 06, 2005
Author(s): Juliana Felippi David and Goés de Azevedo
Original Abstract:
The purpose of this study was to evaluate the surface roughness and wear of bovine enamel submitted to three different bleaching techniques (two in-office and one home bleaching) and simulated brushing. Enamel fragments (1.5cm x 0.5cm and 0.4cm high) were obtained. Half of each specimen was treated with a bleaching agent and submitted to simulated brushing, and the other half was used as control. The specimens were polished and five readings of initial surface roughness were carried out using a roughness meter (Hommel Tester T 1000). The average surface roughness (Ra) was obtained. The specimens were randomly divided into 4 groups (n=10) according to the treatment used: G1= artificial saliva (control); G2= 35% hydrogen peroxide (HP) (Lase Peroxide, DMC Equipamentos), activated with a hybrid light (LED and Diode laser) Ultrablue IV (DMC Equipamentos); HP was applied, and after two minutes it was irradiated with hybrid light for 3 minutes and kept on the specimen for 3 more minutes, with 3 consecutive applications; G3= 35% HP activated with halogen light (Curing Light-3M ESPE Dental Products). The HP was applied and after two minutes it was irradiated with halogen light for 30 seconds, with a 30 second-interval for 3 minutes, the agent being kept on the specimen for 3 more minutes, with 3 consecutive applications; G4= 16% Carbamide Peroxide bleaching agent (16% Whiteness Perfect, FGM) for 2 hours daily during 14 days. The samples were stored in artificial saliva for the remaining time. After bleaching treatment, the surface roughness (Ra) was measured and the specimens were stored in artificial saliva for 7 days, and then subjected to 100,000 simulated brushstrokes. The final roughness (Ra) was determined and three readings of superficial wear were carried out (Hommel Tester T 1000). The superficial roughness average values were statistically analyzed by two-way ANOVA and Tukey test. There were no significant differences among groups comparing initial and post-bleaching roughness. After brushing, there were significant differences between control group and the other experimental groups. G4 showed a significant increase in roughness values compared to G2. Wear was significantly less for G1 compared to the other groups (one-way ANOVA and Tukey test). Bleaching techniques promote increased bovine enamel surface roughness and superficial wear, when submitted to simulated brushing.
http://www.teses.usp.br/teses/disponiveis/25/25131/tde-16082005-114454/
DMC Products used: Lase Peroxide Sensy.

4. Influence of polishing in the superficial roughness of a composite resin submitted to different bleaching techniques
Author(s): Mattos, A. S.*, Costa, L., Motta, C. A. V. B., Santana, E. J. B., Pinheiro, A. L. B., Souto, C. C., Bezerra, R. B.
Abstract
The purpose of this in vitro study was to assess the effect of polishing in the superficial roughness of a composite resin (CR) Z250 (3M ESPE) light cured with LED (Ultrablue IV/DMC), and submitted to the action of two bleaching agents: 10% carbamide peroxide (Whiteness Perfect/FGM) for 4 hours during 21days and 35% hydrogen peroxide (Whiteness HP/FGM), activated by LED, in two sessions and with final polishing using felt disc and polishing paste (Diamond/FGM). The samples remained in distilled water at 37°C during the entire experiment. 60 specimens were prepared in composite resin for the study. 6 groups were formed, with 10 samples each, namely: G.A, CR light cured; G.B, CR light cured and polished; G.C, CR light cured and submitted to the action of CP, G.D, CR light cured, submitted to the action of CP and polished; G.E, CR light cured, submitted to the action of HP and G.F CR light cured, submitted to the action of HP and polished. After these procedures, the superficial roughness reading was carried out using a roughness meter (SJ-201/Mitutoyo), and the results were the following (averages in Ra and standard deviations) G.A (0.45 ± 0.06), G.B (0.39€± 0.03), G.C (0.41 ± 0.08), G.D (0.50 ± 0.07), G.E (0.52 ± 0.07), G.F (0.53 ± 0.07). The data obtained were analyzed statistically (ANOVA, p < 0.05 and Tukey test).
The conclusion is that when the polishing was carried out, the bleaching agents caused a statistically significant increase in the superficial roughness of the samples; and when the polishing was not carried out, the hydrogen peroxide increased the roughness when compared to carbamide peroxide.

5. A scanning electron microscope study of human enamel, dentin, cementum and cementoenamel junction before and after bleaching.
Master’s Dissertation - Dental School, São Paulo State University (UNESP), Araraquara, 2004.
Abstract:
The purpose of this study was to evaluate in SEM the effects of bleaching agents on the surface of human enamel, dentin, cementum and cementoenamel junction, comparing the action of the different techniques and bleaching agents used. Forty five tooth were selected and sectioned longitudinally so ninety specimens were obtained. Forty five specimens served as controls and the other ones were bleached by six protocols: Group I- external bleaching with 10% carbamide peroxide (Opalescence); Group II- external bleaching with 35% hydrogen peroxide (Lase Peroxide); Group III- external bleaching with 35% hydrogen peroxide (Opalescence Xtra); Group IV- internal/external bleaching with 35% hydrogen peroxide (Lase Peroxide); Group V- internal/external bleaching with 35% hydrogen peroxide (Opalescence Xtra) and Group VI- intracoronal bleaching with paste of sodium perborate mixed with 9% hydrogen peroxide. All the specimens were examined in SEM. The specimens of the Groups I, II and III were analyzed externally and the specimens of the Groups IV, V and VI were analyzed internal and externally. The SEM analysis showed some changes on the morphology of enamel, dentin and cementum of all bleached specimens, but the cementoenamel junction were the most affected part of the tooth. The bleaching agents used in this study caused alterations on the shapes of the cementoenamel junction increasing the exposition of dentin in this area and separating the enamel and the cementum. Kruskal-Wallis test was applied (H=6,947). The Groups I, III, V and VI showed similar results but the Groups II and IV showed identical behavior, more aggressive than the others, but not statistically significant.
DMC Products used: Lase Peroxide Sensy.