Influence of different light sources on the temperature rise and effectiveness of three bleaching agents / Avaliação da eficacia de clareamento e do aumento de temperatura de fragmentos dentais submetidos a tres sistemas clareadores, catalisados por diferentes fontes de luz

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

The purpose of this in vitro study was to evaluate quantitatively the tooth color changes, after vital bleaching, induced by various combinations of peroxide bleaching agents and light sources. Additionally, the stability of the obtained color after one month and the temperature rise of the enamel and opposite dentine exposed to a variety of lightcuring units were analysed. The dental specimens were distributed in 15 groups (n=5) according to the bleaching agent: 35% hydrogen peroxide (Opalescence Xtra, Ultradent), 35% hydrogen peroxide (Whiteness HP, FGM) and 37% carbamide peroxide (Whiteness Super, FGM); and to the light source: Quartz Tungsten Halogen light used in bleach mode (Optilux 501C, Demetron), LED associated to a Diode Laser (Ultrablue IV, DMC), Argon Laser (Spectra Physics - Stabilite 2071) and Plasma Arc light - bleach mode (Apollo 95E, DMD). After each treatment session the color alterations were evaluated by spectrophotometric analysis. The temperature variations of enamel and opposite dentine were measured using a laser digital thermometer and a K-type thermocouple connected to a digital thermometer, respectively. The results were submitted to the ANOVA test. For the reflectance, the comparisons among the levels of the factors, in case of qualitative factors (light source and bleaching agent) were accomplished by Tukey test at the 5% significance level. In case of the quantitative factor (treatment session) the degress of freedom were unfolded through the polinomial regression (=0.05). For the temperature, the ANOVA test was accomplished in outline of subdivided parcel, being the parcels represented by the factorial source versus whitening agent and the subparcels by the surface. The 37% carbamide peroxide whitening agent presented the lower reflectance values and were statistically different from a 35% hydrogen peroxide. For the Opalescence Xtra whitening agent, the quartz tungsten halogen light used in bleaching mode presented the highest reflectance means. For the Whiteness HP, the laser presented the lower reflectance means and were statistically different from quartz tungsten halogen light and from the no use of source. For the 35% hydrogen peroxide bleaching agent, there was a color change after one month, however for the 37% carbamide peroxide this change was not observed. The LED/laser source presented the highest temperature increased means in both appraised surfaces. In conclusion, the performance of the light source depends on the bleaching agent used, as well as the behavior of the bleaching agent depends on the light source chosen.

ASSUNTO(S)

dentes - clareamento lasers spectrophotometry calor tooth bleaching lasers heat espectrofotometria

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