This study sought to evaluate the effect of different toothpastes with whitening action on the average surface roughness (Ra) of a microhybrid composite resin. Twenty-five specimens of composite resin were prepared and distributed randomly among 5 experimental groups (n = 5). Groups 1-3 were treated with whitening toothpastes: Close-up Extra Whitening, Colgate Ultra White, and Colgate Total 12 ...

The aim of this study was to evaluate the effect of hydrogen peroxide whitening on fluorescence and color of bovine enamel and dentin. Twenty five dentin discs and 25 enamel discs, with 6 mm diameter and 1 mm thick, were obtained. Direct fluorescence (spectrofluorophotometry) and color (spectrophotometry) were assessed. After fluorescence and color baseline measurements, specimens were immersed...

This study aimed to assess the efficacy of a 35% hydrogen peroxide--based gel without activation in vitro on three areas of the tooth surface. Vestibular faces of human premolar teeth were darkened, followed by two whitenings at 7-day intervals. The efficacy of whitening was determined in the cervical third, medium third and incisal third of the tooth surface with an Easyshade-Vita spectrophoto...

OBJECTIVE Tooth whitening using hydrogen peroxide is a complex process, and there is still some controversy about the roles of pH, temperature, chemical activators, and the use of light irradiation. In this work the basic interactions between whitening agents and stain molecules are studied in simple solutions, thus avoiding the physics of diffusion and light penetration in the tooth to give cl...

for a nite group g the commutativity degree denote by d(g) and dend: d(g) = jf(x; y)jx; y 2 g; xy = yxgj jgj2 : in [2] authors found commutativity degree for some groups,in this paper we nd commuta- tivity degree for a class of groups that have high nilpontencies.

Skin whitening products are commercially available for cosmetic purposes in order to obtain a lighter skin appearance. They are also utilized for clinical treatment of pigmentary disorders such as melasma or postinflammatory hyperpigmentation. Whitening agents act at various levels of melanin production in the skin. Many of them are known as competitive inhibitors of tyrosinase, the key enzyme ...

Tooth whitening has become increasingly popular; according to the American Academy of Cosmetic Dentistry, Americans spend 1.4 billion dollars per year on tooth whitening. There are several approaches including use abrasives for mechanical removal material, colorants, and oxidation chromophores that make stains [1,2].