Acción de los agentes blanqueadores sobre materiales de restauración / Action of bleaching agents on restorative materials

El propósito del trabajo será analizar comparativamente los diversos efectos que producen sobre las restauraciones dentales agentes blanqueadores.El objetivo será valorar los cambios que experimentan en la superficie los materiales de restauración, sometidos a la acción de un agente blanqueador. La metodología utilizada será visualización microscópica electrónica de barrido ambiental. Los resultados obtenidos tendrán transferencia relevante a Insti-tuciones formadoras de recursos humanos en Salud Bucal, al campo profesional odontológico y a empresas o fabricantes para el mejoramiento de su producto...

Vital tooth whitening.

Vital tooth whitening, when administered correctly, is by all accounts one of the safest, most conservative, least expensive, and most effective aesthetic procedures currently available to patients. This article traces the evolution of the technology, describes what is known about the mechanism of action and explores such issues as toxicology and side effects associated with tooth whitening. The article also describes the various tooth-whitening systems, which include dentist-supervised night-guard bleaching, in-office or power bleaching, and bleaching with over-the-counter bleaching products. Combination treatments and light-activated treatments are also discussed. Finally, the article summarizes the areas of research needed in this field.

Comparison of the ability of different colour indices to assess changes in tooth whiteness.

OBJECTIVES: The study investigates the suitability of different whiteness indices and colour parameters in assessing changes in tooth whiteness using a digital-colour imaging system. METHODS: Forty-six male and female subjects aged 18-70 years participated in the study and were divided into two groups. The control group was given a standard "non-whitening" dentifrice (Colgate Great Regular Flavour) and the test group received whitening strips (crest white strips). The latter contained 6% hydrogen peroxide and were worn for 30 min twice daily on the six maxillary anterior teeth. Digital images of teeth were captured using a Jai 3CCD digital camera with annular LED illumination array and the data obtained was used to calculate colour parameters (L*, a* and b*) and whiteness indices (WIC, WIO, W). Colour differences (delta L, delta a, delta b and delta E) and differences in whiteness indices were obtained and were compared between the test and control groups. Reliability and repeatability of the instrument were checked by comparing the digital data to the clinical data and also by comparing data obtained from different camera views for the same tooth. RESULTS: The test group showed significant changes in the colour parameters and whiteness indices over the 2-week period. It also showed significant correlation between the digital data obtained from lateral and central camera views for the same teeth. Digital data showed a similar trend to that of clinical data. The WIO index demonstrated the strongest discrimination between the test and control groups. CONCLUSION: The WIO index is appropriate for assessing changes in tooth whiteness. The digital imaging system is reproducible and reliable in evaluating changes in whiteness of teeth.

The art and science of tooth whitening.

Although tooth whitening is one of the most popular dental procedures, it is also one of the least understood. We are still unclear as to its mechanism of action. There is little data as to the effects of both concentration and dose on outcome. The techniques for measuring color change have been brought into question. The cause(s) of sensitivity and the effects of long-term exposure to hydrogen peroxide are not clear. The issue of rebound in color has not been well examined, and issues related to maintenance of the whitening effect are also poorly understood. The immediate placement of composite resin on bleached teeth has been controversial. According to a study evaluating the shear bond strength of composite restorations placed on bleached and nonbleached teeth, there was no statistically significant difference when the composites were placed at 24 hours, 48 hours, four days, or six days. A different study, which evaluated the effects of take-home bleaching systems on enamel surfaces, suggests that a period of four days must elapse before bonding to a tooth bleached with a peroxide material, while no delay is necessary for a non-peroxide-based bleaching system. Most recently, there has been a push to find ways to accelerate and improve the delivery of the whitening process. These include the application of a number of different light sources believed to accelerate the breakdown of peroxide and thus speed up the whitening process. However, the research in this area has been controversial, with publications having quite different conclusions as to the efficacy of light-activated bleaching. Finally, the issues of adverse events and possible side effects were reviewed. The toxicological side effects of tooth bleaching systems seem to be minimal. However, tooth sensitivity can be quite significant. Although its causes are poorly understood, tooth sensitivity is most often seen as the result of tooth dehydration. So while patient demand for tooth whitening is at an all-time high, and dentists have more options for treatment, it's important that dentists evaluate which of these options is most ideal for their patients, factoring in the patients' cost and time issues, as well as sensitivity to the procedure.

Comparison of clinical efficacy and safety of three professional at-home tooth whitening systems.

A three-cell, randomized, parallel, investigator-blinded clinical trial was conducted to compare the efficacy and safety of three professional at-home tooth whitening systems, including Crest Professional Whitestrips (6.5% H2O2), Day White 2 (7.5% H2O2) and Nite White Excel 2 (16% carbamide peroxide equivalent). Ninety subjects were randomly assigned to three groups (30/group). Subjects were instructed to use the assigned whitener following the manufacturers' instructions. Clinical examinations at baseline, and on days 3, 7, 14, and 18 (Day White), or 21 (Crest Professional Whitestrips and Nite White) included the following parameters: 1) oral tissues; 2) tooth shade by the Vitapan Classical shade guide; 3) tooth shade by a chromameter with a jig; and, 4) tooth sensitivity and gingival irritation. The results showed significant shade reductions with time in all three groups. Nite White resulted in significantly greater shade reductions in periods between days 7, 14, or 21 and baseline than did the other two systems. Tooth sensitivity and gingival irritation, which were mostly mild and transient, occurred in all groups. It is concluded that all three whitening systems evaluated are effective and safe. Nite White Excel is superior to the other two systems because it provides a greater whitening efficacy with comparable or lower incidence of tooth sensitivity and gingival irritation.