Spectrophotometric assessment of the effects of 10% carbamide peroxide on enamel translucency

Abstract

Tooth shade results from the interaction between enamel color, enamel translucency and dentine color. A change in any of these parameters will change a tooth's color. The objective of this study was to evaluate the changes occurring in enamel translucency during a tooth whitening process. Fourteen human tooth enamel fragments, with a mean thickness of 0.96 mm ( 0.3 mm), were subjected to a bleaching agent (10% carbamide peroxide) 8 hours per day for 28 days. The enamel fragment translucency was measured by a computer controlled spectrophotometer before and after the bleaching agent applications in accordance with ANSI Z80.3-1986 -American National Standard for Ophthalmics -nonprescription sunglasses and fashion eyewear-requirements. The measurements were statistically compared by the Mann-Whitney nonparametric test. A decrease was observed in the translucency of all specimens and, consequently, there was a decrease in transmittance values for all samples. It was observed that the bleaching procedure significantly changes the enamel translucency, making it more opaque.

Separate contribution of enamel and dentine to overall tooth colour change in tooth bleaching

“…Vieira 25 and Ma et al 14 reported that the bleaching procedure significantly changed the enamel translucency, making it more opaque. In the enamel-dentine system, along with the decrease in enamel translucency, more light was reflected within the enamel, leading to more light reflected to the human eye.…”

“…In other words, the object would seem lighter. 25 Enamel consisted of large amount of inorganic materials and very small amount of organic phase such as protein and water. 26 The decrease in translucency of enamel sample would be related to partial removal of mineralized tissues and organic matrix, which might be affected by the etching and oxidization of bleaching gels.…”

“…Taking all the previous information into consideration, it could be said that enamel and dentine colour as well as enamel translucency determine the colour of teeth. 25 It has been pointed out that the results were condition dependent. Most of the time enamel and dentine are both treated simultaneously in vivo and the optical changes are both acting together.…”

Color and contrast ratio of resin composites for whitened teeth

“…20 The correlation of opacity and lightness of resin composites observed in this study correlates well with an in vitro study that demonstrated that whitening with 10% carbamide peroxide increases the opacity of enamel. 21 In this regard, resin composite materials designed for whitened teeth follow a similar pattern as natural enamel.…”

Efeito da ativação química do gel de peróxido de carbamida a 10% no clareamento dental

“…Tagami et al (1989), mostraram que a permeabilidade da dentina coronal de incisivos bovinos é semelhante ao da dentina próxima à junção amelo-cementária dos dentes humanos. Schiavoni et al (2006) Vários pesquisadores utilizaram espectrofotômetros e colorímetros em suas pesquisas, (Frysh et al, 1995;Lenhard, 1996;O'Brien et al, 1997;Horn et al, 1998;Jones et al, 1999;Carvalho et al, 2002;Gallagher et al, 2002;Alves et al, 2006;Dietschi et al, 2006;Travassos et al, 2010;Wiegand et al, 2005;Caneppele, 2008;Vieira et al, 2008). A grande vantagem do uso de colorímetros ou espectrofotômetros em relação à visão humana é a objetividade da leitura, segundo Paul et al (2002), a determinação espectrofotométrica das cores é mais precisa e mais reprodutível em comparação com a avaliação visual (83,3% comparado a 26,6%).…”