Bleaching effectiveness and cytotoxicity of new experimental formulation of niobium-based bleaching gel.

OBJECTIVES: The development of new bleaching agents with minimum concentration of hydrogen peroxide (HP), without adverse effects, and with bleaching effectiveness, has great clinical relevance. The aim of this study was to evaluate the bleaching efficacy and cytotoxicity of a new niobium-based bleaching gel, compared to already available HP-based gels. MATERIALS AND METHODS: For the bleaching efficacy analysis, 40 bovine incisors were randomly divided into 4 groups according to the established bleaching protocol: control, untreated; 35HP, 35% HP bleaching gel; 6HP, 6% HP bleaching gel; NbHP, niobium gel associated with 3% HP gel. The color variation was measured in a spectrophotometer and the values of ΔL, Δa, Δb, and ΔE obtained. For the cell viability assay by MTT, MC3T3 cells were exposed to bleaching gel extracts (1:500, 1:250, 1:125 dilutions; immediately and 24 h). Statistical tests were performed (P < 0.05). RESULTS: The color alteration for all bleaching gels was significant compared to control (P < 0.05), but the NbHP gel showed a significant ΔE than other gels, with expressive color alteration at 14 days (P < 0.05). The 35HP showed high cytotoxicity regarding control and the most groups in all periods and extracts analyzed (P < 0.05), while the NbHP showed greater cell viability than control in the immediate period, dilution of the 1:500 and superior to 6HP in the most extracts at 24 h. CONCLUSION: The new experimental niobium-based gel has bleaching efficacy similar to that of gels with a high concentration of HP, and it has high cytocompatibility. CLINICAL RELEVANCE: The use of this new generation of niobium-based whitening gel associated with a low concentration of hydrogen peroxide represents the possibility of a tooth whitening with lower dentin sensitivity.

Técnica modificada de blanqueamiento de dientes vitales empleando DMC peróxido de hidrógeno al 35% / Modified technique for vital teeth whitening using DMC 35% hydrogen peroxide

RESUMEN Introducción: Los fabricantes de DMC peróxido de hidrógeno al 35% proponen una técnica de blanqueamiento de dientes vitales que malgasta el producto y el tiempo de tratamiento, por lo que una técnica modificada traería beneficios materiales y económicos para operadores y pacientes. Objetivo: Describir la aplicación de una técnica modificada de blanqueamiento dental en dientes vitales utilizando DMC peróxido de hidrógeno al 35%. Presentación del caso: Paciente femenina de 44 años a quien se le realiza un tratamiento de blanqueamiento dental con una modificación de la técnica propuesta por el fabricante del producto. La modificación consistió en el empleo de una sola aplicación del gel blanqueador, en lugar de tres aplicaciones, y aumento del tiempo de exposición a 40 min, en lugar de los 10-15 min recomendados por el fabricante. Las variables empleadas para evaluar el tratamiento y sus resultados fueron definidas por el registro del color inicial y posterior al tratamiento, y por la satisfacción de la paciente con el resultado del mismo. Los dientes expuestos al tratamiento se encontraban con tejidos de esmalte sanos sin exposición de la dentina en ninguna de las superficies. Conclusiones: La modificación descrita de la técnica de blanqueamiento propuesta por el fabricante con DMC Lase Peroxide Sensy (peróxido de hidrógeno al 35%) consistente fundamentalmente en el empleo de una sola aplicación y aumento del tiempo de exposición en una sola sesión de tratamiento, aportó un ahorro del producto sustancial y condujo al cambio de la coloración final de los dientes, con la plena satisfacción de la paciente y protegido el esmalte superficial de sus dientes tratados.

ABSTRACT Introduction: The manufacturers of DMC 35% hydrogen peroxide propose a whitening technique of vital teeth that waste the product and the time of treatment, so a modified technique would bring material and economic benefits for operators and patients. Objective: To describe the application of a modified technique in vital teeth whitening using DMC 35% hydrogen peroxide. Case presentation: A 44-year-old female patient undergoing a whitening treatment with a modification of the technique proposed by the product manufacturer. The modification consisted in the use of a single application of the bleaching gel instead of three applications, and an increase in the exposure time to 40 min instead of the 10-15 min recommended by the manufacturer. The variables used to evaluate the treatment and its results were defined by the registration of the color before and after treatment and also by the satisfaction of the patient with the result. The teeth exposed to treatment were found with healthy enamel tissues without dentine exposure on any of the surfaces. Conclusions: The described modification of the whitening technique proposed by the manufacturer with DMC Lase Peroxide Sensy (35% hydrogen peroxide) consisting mainly on the use of a single application and the increase of the exposure time in a single treatment session contributed to a considerable saving of the product and led to the change of the final coloring of the teeth, which resulted in the full satisfaction of the patient and the protection of her exposed teeth and tissues.

Aumento de la temperatura intracámara pulpar durante el blanqueamiento con sistemas activados por luz: revisión de la literatura / Temperature increase intracameral pulp during bleaching with light-activated systems: review of the literature

Son varias las fuentes de energía utilizadas para acelerar la descomposición del peróxido de hidrógeno durante el blanqueamiento realizado en el consultorio. Durante su aplicación, los sistemas de blanqueamiento dental que utilizan fuentes de energía, aumentan la temperatura de los tejidos dentarios. Existen evidencias de que el aumento de la temperatura intracámara pulpar puede causar daño a este tejido. Este trabajo tuvo por objetivo presentar a través de una revisión de la literatura los diferentes tipos de luz utilizados para blanqueamiento y el calentamiento intracámara pulpar generado por estos. El aumento de temperatura intracámara pulpar crítico es considerado de 5,5º C. En estudios in vitro varios son los sistemas y combinaciones de tiempo que llegan o pasan esta temperatura. Antes de la utilización de estos sistemas el odontólogo debe conocer los riesgos existentes y leer las instrucciones de los fabricantes

To accelerate the decomposition of hydrogen peroxide during the in-office bleaching process, various energy sources can be used. During the application of these energy systems, an increase of temperature in teeth tissue has been reported. The temperature rise in the pulp might be harmful to this tissue. The objective of this work was to present through a literature review the different lights for an in-office bleaching and the resultant intrapulpal temperature rise produced by these lights. The critical temperature rise in pulp chamber is considered to be 5.5º C. On in vitro studies there are many systems and time combinations that achieved or passed this critical limit. Before the use of any energy source for the in- office bleaching, the dentist should be concerned about the existing risk and must read the manufacturer's instructions