Effect of Nano-Pulsed Cold Laser (NPCL) Light on Calcium and Phosphate Loss from Dental Enamel During In-office Bleaching with High Concentrated Hydrogen Peroxide Using Atomic Absorption Spectophotometer

To assess calcium and phosphate loss from enamel using 37.5% hydrogen peroxide (HP) gel with additional application of light emitting diode (LED), Diode laser and Nano-Pulsed Cold laser (NPCL) light sources compared to that of 37.5% HP alone using atomic absorption spectrophotometer (AAS). Methods: Twenty teeth were sectioned to obtain mesiobuccal, distobuccal, mesiopalatal and distopalatal specimens. The specimens were randomly assigned to four equal groups. 37.5% HP of 1mm thickness was applied to the enamel surface of each specimen. Each group received three cycles of bleaching of 8 minute’s duration. Group II, III & IV received additional application of LED, Diode laser & cold laser light respectively. Results: Data was analyzed by means of descriptive statistics. Group III showed the maximum loss of ions while Group IV showed the least loss and the differences were statistically significant (P < .05). Conclusion: Teeth treated with 37.5% hydrogen peroxide with application of Nano-Pulsed Cold Laser (NPCL) light presented with significantly minimal calcium and phosphate loss

Bleaching of stained resin using nitrogen doped-TiO₂ nanoparticles / 대한치과재료학회지

There has been increasing use of the H₂O₂-based teeth bleaching agents. The purpose of this study was to evaluate the bleaching effectiveness of the laser irradiation combined with nitrogen doped-TiO₂ nanoparticles (NPs) on the stained resin. Nitrogen (N) doped-TiO₂ NPs were prepared under sol-gel method. Light absorbance, X-ray diffraction patterns of NPs, and bleaching of methylene blue and stained resins were evaluated. For bleaching of stained resin, NPs-containing gel was used. For irradiation, light of two different wavelengths was used. Unlike TiO₂, N-TiO₂ showed high absorbance after 400 nm. N-TiO₂, which have used TiN as a precursor, showed a new rutile phase at the TiN structure. For methylene blue solution, N-TiO₂ with 3% H₂O₂ resulted in the greatest absorbance decrease after laser irradiation regardless of wavelength. For stained resin test, N-TiO₂ with 3% H₂O₂ resulted in the greatest color difference after laser irradiation, followed by group that used N-TiO₂ without 3% H₂O₂.

Aclaramiento Dental con Enjuagues de Libre Venta que Contienen Peróxido de Hidrógeno / Toothbleaching with over the Counter Mouthwashes Containing Hydrogen Peroxide

RESUMEN: El objetivo de este estudio in vitro fue evaluar la eficacia en el aclaramiento dental de tres enjuagues orales que contienen peróxido de hidrógeno en diferentes períodos de inmersión en comparación con el peróxido de carbamida al 10 %. Cuarenta muestras de premolares humanos se dividieron aleatoriamente en cuatro grupos según el agente al que se expuso: G1: Colgate Plax®Whitening, G2: Listerine®Whitening Extreme y G3: Oral B® 3D White™ se sumergieron dos minutos al día durante 28 días y G4: Peróxido de carbamida al 10 %, ocho horas al día durante 14 días. La medición de color se realizó con un espectrofotómetro Vita Easyshade usando la escala CIELab inicialmente, a los 14, 28 y 35 días de evaluación. Las comparaciones entre los grupos se realizaron utilizando las pruebas Kruskal-Wallis y U Mann-Whitney, mientras que entre los tiempos las pruebas Friedman y Signo-Rango de Wilcoxon. Los resultados revelaron que a los 14 días, los cuatro grupos mostraron cambios de color, pero no se evidenció mayor eficacia de alguno sobre el otro (p>0,05). Sin embargo, a los 28 y 35 días se observó una clara eficacia del peróxido de carbamida sobre los enjuagues (p<0,05). Los enjuagatorios orales aclaran los dientes a partir de los 28 días, con los protocolos indicados; sin embargo no llegan a tener resultados similares a un aclaramiento profesional con gel de peróxido de carbamida al 10 %.

ABSTRACT: The objective of this in vitro study was to evaluate the efficacy in dental toothbleaching of three mouthwashes containing hydrogen peroxide in different periods of immersion compared to 10 % carbamide peroxide. Forty samples of human premolars were randomly divided into four groups according to the agent to which they were exposed: G1: Colgate Plax®Whitening, G2: Listerine®Whitening Extreme and G3: Oral B® 3D White ™ were immersed two minutes a day during 28 days and G4: 10 % carbamide peroxide, eight hours a day for 14 days. The color measurement was performed with a Vita Easyshade spectrophotometer using the CIELab scale initially, at 14, 28 and 35 days of evaluation. The comparisons between the groups were made using the Kruskal-Wallis and U Mann-Whitney tests. While between the times the tests Friedman and Sign-Range of Wilcoxon. The results revealed that at 14 days, the four groups showed color changes, but no greater effectiveness was shown of one over the other (p>0,05). However, at 28 and 35 days a clear efficacy of carbamide peroxide was observed on the rinses (p<0,05). Mouthwashes clear the teeth after 28 days, with the indicated protocols; however, they do not reach similar results to a professional clarification with 10 % carbamide peroxide gel.

The effect of Remin Pro® on bleached enamel hardness: An in-vitro study.

Introduction: Remineralization as a treatment procedure has received a lot of attention both from clinicians as well as researchers. The objective of this study was to assess the effect of Remin Pro® on enamel microhardness after bleaching the teeth with McInnes bleaching agent using Vickers microhardness tester. Materials and Methods: In this study, freshly extracted ten central incisors were taken which were subjected to baseline indentation by using Vickers microhardness indenter and then McInnes bleaching solution was applied for 5 min to demineralize these teeth. Remin Pro a newer remineralizing agent was applied for 7 days, which showed an increase in microhardness at the end of 7 days. Results: The values were subjected for statistical analysis using paired t‑test. All the samples showed a decrease in the microhardness after bleaching with McInnes solution. The decrease in mean hardness from baseline to demineralization was found to be statistically significant (P < 0.001). However, remineralizing the same tooth with Remin Pro for 7 days, showed an increase in hardness, which was found to be statistically significant (P < 0.05). Conclusion: McInnes bleaching agent decreases the microhardness of enamel and Remin Pro® used in the study causes an increase in the microhardness of bleached enamel.

Cytotoxicity of non-vital dental bleaching agents in human gingival fibroblasts / Avaliação da citotoxicidade de agentes clareadores de uso interno sobre fibroblastos gengivais humanos

Objective: The aim of this study was to compare several non-vital dental bleaching agents for their in vitro cytotoxicity to human gingival fibroblasts primary cell line. Methods: The cells were cultivated in DMEM and were seed in plates of 96 wells; then, it was exposed to the conditioned medium according to the experimental groups (n = 12): G1 - SP (sodium perborate) + distilled water; G2 - SP + 20% CP (carbamide peroxide); G3 - 20% CP; G4 - SP + 35% HP (hydrogen peroxide); G5 - 35% HP. In the control group (n = 12), corresponded to the curve of cell growth and viability, the cells did not receive any treatment. Cell viability was measured photometrically using a MTT assay after a 24 h and 48 h of exposure period. Data were submitted to ANOVA and Tukey’s tests. Results: All the experimental groups presented high cytotoxicity statically in comparison to the control group. The rank of the most to the least toxic material after 24 h was: SP + DW > 35% PH > PS + 20% PC > PS + 35% PH > 20% PC; and after 48 h was: SP + DW > PS + 20% PC > 35% PH > PS + 35% PH > 20% PC. Conclusion: All the bleaching agents had presented cytotoxicity effects, reducing significantly the cell viability, however, in the conditions that the study was conducted the association of sodium perborate with distilled water was the most toxic bleaching agent

Objetivo: O objetivo deste estudo foi comparar a citotoxicidade de agentes clareadores de uso interno em linhagem primária de fibroblastos humanos. Material e Método: As células foram cultivadas em meio DMEM e semeadas em placas de 96 poços. Em seguida, foram expostas aos meios de cultura condicionados de acordo com os grupos experimentais (n = 12): G1 - PS (perborato de sódio) + água destilada; G2 - PS + PC 20% (peróxido de carbamida); G3 - PC 20% ; G4 - PS + PH 35% (peróxido de hidrogênio); G5 - PH 35%. No grupo controle (n = 12), correspondente à curva de crescimento e viabilidade celular, as células não receberam nenhum tratamento. A viabilidade celular foi verificada por espectofotômetro utilizando o ensaio de MTT, após um período de 24 e 48 h de exposição aos agentes clareadores. Os dados foram submetidos aos testes de ANOVA e Tukey. Resultados: Todos os grupos experimentais apresentaram alta citotoxicidade em relação ao grupo controle. O rank de citotoxicidade dos agestes clareadores após 24 h foi: PS + AD > PH 35% > PS + PC 20% > PS + PH 35% > PC 20% e após 48h foi: PS + AD > PS + PC 20%> 35% PH > PS +PH 35% > 20% PC. Conclusão: Todos os agentes clareadores apresentaram efeitos citotóxicos, reduzindo significativamente a viabilidade da celular. Entretanto, nas condições em que o estudo foi conduzido a associação do perborato de sódio com água destilada, foi o agente clareador mais tóxico

The effect of carbamide peroxide bleaching agents on the microhardness of dental ceramics

This study examined the effect of 10% and 16% carbamide peroxide bleaching agents on the surface microhardness of micro-particulate feldspathic ceramics (VM7 and VM13, Vita Zahnfabrik). Forty specimens (8-mm diameter, 2-mm thickness) were divided into four groups (n=10): G1- VM7 + 10% Whiteness, G2- VM7 + 16% Whiteness, G3- VM13 + 10% and G4- VM13 + 16% Whiteness. The home-use bleaching agents were applied for 8 hours on 15 days, and the specimens were stored in distilled water at 37°C. The Vickers hardness number (HV) was determined for each specimen. Data were analyzed by the Wilcoxon and Mann- Whitney tests (p<0.05). The microhardness values before exposure were: g1- 433 (57); g2- 486 (22); g3- 509 (28); g4- 518 (24), and after exposure: G1- 349 (32); G2- 496 (95); G3- 519 (38); G4- 502 (81). G2 exhibited a higher and significant difference than G1 in VM7 groups, and the effect of bleaching concentration was shown to be significant by the Mann-Whitney test. And for VM13, both the Wilcoxon and Mann-Whitney tests showed no significant differences. When using 10% carbamide peroxide, the microhardness of VM7 ceramic was affected, and there were no effect on the microhardness between VM7 and VM13 ceramics when 16% carbamide peroxide was used.

Este estudo examinou o efeito do agente clareador peroxido de carbamida a 10% e a 16% na microdureza superficial de ceramicas feldspaticas micro-particuladas (VM7 e VM13, Vita Zahnfabrik). Quarenta corpos-de-prova (8 mm de diametro, 2 mm de espessura) foram divididos em quatro grupos (n=10): G1- VM7 + 10% Whiteness, G2- VM7 + 16% Whiteness, G3- VM13 + 10% e G4- VM13 + 16% Whiteness. Os agentes clareadores foram aplicados por 8 horas durante 15 dias e os cp foram armazenados em agua destilada a 37°C. A dureza Vickers (HV) de cada cp foi determinada. Os dados foram analisados pelos testes de Wilcoxon e Mann-Whitney (p<0.05). Os valores da dureza antes da exposicao ao agente clareador foram: g1- 433 (57); g2- 486 (22); g3- 509 (28); g4- 518 (24), e depois da exposicao: G1- 349 (32); G2- 496 (95); G3- 519 (38); G4- 502 (81). G2 exibiu diferenca significante e microdureza maior comparado ao G1 nos grupos da VM7 e o efeito da concentracao do clareador foi significante, apresentados atraves dos testes Mann-Whitney. Para VM13, ambos testes, Wilcoxon e Mann-Whitney, nao apresentaram diferenca significante. Quando o peroxido de carbamida a 10% foi avaliado, a microdureza da ceramica VM7 foi afetada, e nao houve diferenca na microdureza entre as ceramicas VM7 e VM13 quando o peroxido de carbamida a 16% foi utilizado.

The use of ozone to lighten teeth: An experimental study

Tooth-whitening agents are available for therapeutic use in the dental office or at home. However, whitening more severe stains, such as those caused by systemic ingestion of tetracycline, constitutes a challenge. The aim of this study was to evaluate, in an experimental model of growing rats, the efficacy of using ozone to lighten tetracycline-stained incisors. At weaning, male Wistar rats (n=40) were randomly assigned to one of three groups. Two control groups, C21 and C60 (n=8, each) were used to document the usual age-related color. The third group (n=24) received 0.25 g% of oxytetracycline (O) until 60 days of age. These rats were subsequently divided into three further groups: O0, O3 and O5 (n=8, each). These rats were anesthetized; O3 and O5 groups received ozone application to the lower incisors for 3 (group O3) or 5 minutes (group O5), respectively; while O0 did not receive the ozone treatment. Teeth were then photographed and the incisors from the control (C60) and treatment groups (O0, O3 and O5) were cut, and compared to a standard color guide (there were eight shades numbered 0 to 7, lightest to darkest) to assess the hue visually. The teeth were then placed in phosphoric acid to quantify the color by spectrophotometry. The data (mean ± SD) were analyzed by One-Way Analysis of Variance (ANOVA) followed by Tukey's test or Dunnett test. The visual observation, analyzed blindly by one investigator, showed that O3 and O5 groups had diminished yellowing of the teeth as compared to the untreated O0 group (P<0.001). The color quantified by spectrophotometry also detected significant differences among groups (O3 < O0, P<0.01; O5 < O0,P < 0.001 and O5 < O3, P<0.01). C21 and C60 were significantly different among groups (P<0.001). This is the first experimental study to show that ozone can be successfully used for lightening the yellowish tinge of tetracycline- stained rat incisors. Further studies are required for its potential use in the dental clinic.

Los agentes blanqueadores dentales estan disponibles para tratamientos que se realizan en el consultorio odontologico o en el domicilio. Sin embargo, aclarar manchas severas, como las causadas por la ingestion sistemica de tetraciclina, constituyen un desafio. El objetivo de este estudio fue evaluar en un modelo experimental de ratas en crecimiento, la eficiencia del uso de ozono para aclarar los incisivos oscurecidos por el uso de tetraciclina. Ratas macho Wistar al destete (N=40) fueron asignadas aleatoriamente a uno de tres grupos. Dos de ellos grupos controles, C21 y C60 (N=8, cada uno), para documentar el color habitual de los incisivos, correspondiente a la edad del animal. El tercer grupo (N = 24) recibio 0,25 % de oxitetraciclina (O) hasta los 60 dias de edad. Entonces, el grupo O se dividio aleatoriamente en tres grupos O0, O3 y O5 (N = 8, cada uno) y las ratas se anestesiaron. Los grupos O3 y O5 recibieron en los incisivos inferiores la aplicacion de ozono durante 3 y 5 minutos, respectivamente; mientras que O0 no recibio tratamiento. Los incisivos de C60, O0, O3 y O5 fueron fotografiados. Luego se cortaron y se contrastaron con una guia estandar de ocho colores (ordenados de 0 a 7, desde el mas claro a mas oscuro) para cuantificar visualmente el color de los incisivos. Luego, se colocaron en acido fosforico para cuantificar el color por espectrofotometria. Los resultados (media ± SD) se analizaron por medio de ANOVA y prueba de Tukey o Dunnett (α =0.05) para determinar el efecto del tratamiento. El analisis visual de las imagenes mostro que los grupos O3 y O5 disminuyeron el color amarillo intenso respecto a O0. Dicha diferencia de color fue evaluada a traves de la guia (G) y cuantificada mediante espectrofotometria (E). Segun G, la mayor diferencia de color respecto a C60 fue para O0 (P<0.001), disminuyo en O3 (P<0.001) y aun mas en O5 (P<0.01). De acuerdo a E, O3

Chemical Burn due to a Hair Bleaching Agent / 대한피부과학회지

Several hair dressing procedures, for example, bleaching and dyeing of the hair, are currently being frequently performed for cosmetic purposes. While allergic contact dermatitis due to hair dressing products has often been described, only a few cases of burns caused by hair dressing chemicals have been reported. A 6-year-old girl presented with an 8x6 cm sized round ulcerative lesion on the occipital area after hair bleaching with ammonium persulfate mixed with hydrogen peroxide. The skin biopsy specimen showed epidermal necrosis and sclerosing change in the dermis. She was referred to another burn center and then she was treated with skin grafting by a plastic surgeon. To the best of our knowledge, this is the first reported case of chemical burn due to a hair bleaching agent in the Korean dermatologic literature.

Effects Of Tooth-Whitening Agent On Enamel And Dentin: A Confocal Laser Scanning Microscopy Study / 대한치과보철학회지

The purpose of this study was to estimate the effect of a bleaching agent on tooth surfaces and to evaluate the resin bond strength according to different surface treatments on bleached teeth.To prepare for the experimental samples,first,extracted human third molars were used and the body portions of the crowns were cut into four equal-sized specimens.Next,each specimen was mounted in an plastic bottle with self-cured resin and highly polished to have them reveal the enamel or dentin surfaces.Then,the enamel(E)and dentin(D)specimens were divided into four; 1) non-bleached,laser-treated(NBLA)group 2)bleached,laser-treated(BLLA)group 3)non-bleached,acid-treated(NBAC)group and 4)bleached,acid-treated(BLAC)group.Here,opales-cence(R)(10%carbamide peroxide)was used for bleaching agent.The treated specimens were observed by confocal laser scanning microscopy and bonded with composite resin for shear bond test. The following results were obtained from this experiment : 1. Compared with the ENB group,the EBL group was shown to be dyed about 20 micrometer deeper with rhodamine B.The DBL group appeared to be caved in at the entry part of the dentinal tubules, was dyed about 20 micrometer deeper and 5 micrometer wider in diameter,compared with the DNB group. 2. In comparison with the EBLAC group,the ENBAC group looked evenly bonded with the resin, while the DNBAC group,compared to DBLAC group,was observed to have its resin tags penetrated about 50 micrometer deeper.Other than those,however,no observable differences between ENBLA and EBLLA group or between DNBLA and DBLLA group were found. 3. At the shear bond test,the ENBAC group was shown to have statistically significant higher shear bond strength than the EBLAC group(p0.05). 4. At the shear bond test,the DNBAC group was shown to have statistically significant higher shear bond strength than the DBLAC group(p0.05). The in vitro observations above suggest that tooth-bleaching procedure brings a certain change on enamel and dentin surfaces and it weakens the shear bond strength with composite resin when the bleached tooth was acid-treated.