nÃo hà / O uso do perÃxido de carbamida a 10% em moldeiras para o clareamento caseiro por 2 a 8 horas diÃrias, de 2 a 6 semanas pode resultar em grande satisfaÃÃo do paciente. A associaÃÃo de dentes brancos a um aumento da autoestima do indivÃduo promoveu o aparecimento de agentes clareadores disponÃveis para a compra sem, necessariamente, passar pela supervisÃo do dentista. Como consequÃncia, podem surgir efeitos adversos na estrutura dental. Baseado nesse contexto, o presente estudo avaliou a microdureza do esmalte apÃs a utilizaÃÃo de agentes clareadores. 70 amostras de esmalte humano, com 4x4mm, foram divididas em sete grupos (G1 a G7). Cada grupo recebeu trÃs tratamentos por 28 dias: G1: pasta nÃo clareadora, Ãgua destilada e gel placebo; G2: pasta clareadora, Ãgua destilada e gel placebo; G3: pasta nÃo clareadora, enxaguatÃrio clareador e gel placebo; G4: pasta nÃo clareadora, Ãgua destilada e gel perÃxido de carbamida a 10%; G5: pasta clareadora, Ãgua destilada e gel de perÃxido de carbamida a 10%; G6: pasta nÃo clareadora, enxaguatÃrio clareador e gel de perÃxido de carbamida a 10%; G7: pasta clareadora, enxaguatÃrio clareador e gel de perÃxido de carbamida a 10%. A microdureza foi aferida antes dos tratamentos, com 14 dias e no 28Âdia. AtravÃs da anÃlise de variÃncia ANOVA verificou-se diferenÃa entre os tipos de tratamento. Para os nÃveis de tempo, o teste de Tukey mostrou diferenÃas significativas nas medidas antes, apÃs 14 e 28 dias. O G2 se comportou estatisticamente semelhante ao G1. O G3 e G6 se mostraram estÃveis durante todo o tratamento. O G4 e G5 nÃo mostraram diferenÃa significativa entre si. O Ãnico grupo que desmineralizou significativamente entre os trÃs nÃveis de tempo foi o G7. Logo, demonstra-se que a reduÃÃo da microdureza ocorreu de forma mais intensa pelo uso coletivo de agentes clareadores durante o tratamento.

In recent years bleaching of vital teeth has become popular among both dentist and patients. Different bleaching agents were used for this purpose. They are either applied professionally at high dose (office bleaching) or by patient at lower dose (home bleaching). In the present work we studied the effects of a high concentration bleaching agent (35% hydrogen peroxide), and a low concentration bleaching agent (17% carbamide peroxide) on human enamel and dentin using Fourier Transform Infrared (FTIR) Spectroscopic Technique. The OH stretching band of hydroxyapatite at 3567 cm-1 appeared in the spectra of enamel tissue which was absent in dentin. Carbamide peroxide and hydrogen peroxide treatment induced some differences in enamel and dentin spectra according to control group spectra. While the treatment of hydrogen peroxide leaded to significant decrease in mineral to matrix ratio, carbamide peroxide treatment did not cause decrease in this level. In addition, organic components of the teeth were changed after the treatment of bleaching agents. The frequency of the Amide A and Amide I bands were significantly changed for enamel tissue after the treatment of high concentration bleaching agent. However, it is observed that these changes result from two different bleaching methods are negligible in dentin tissue. In conclusion it can be stated that hydrogen peroxide treatment caused dramatic changes in enamel structure according to carbamide peroxide treatment, but two methods did not cause significant changes in dentin tissue.

Tooth-whitening or tooth-bleaching has become an integral part of modern dental practice. Today, a large number of whitening products are available on the market which are commonly categorized into dentist-supervised home bleaching, in-office bleaching and over-the-counter bleaching products according to their mode of application. This thesis looks into safety and efficacy of various tooth-whitening products and methods.

Tooth-whitening or tooth-bleaching has become an integral part of modern dental practice. Today, a large number of whitening products are available on the market which are commonly categorized into dentist-supervised home bleaching, in-office bleaching and over-the-counter bleaching products according to their mode of application. This thesis looks into safety and efficacy of various tooth-whitening products and methods.

Philosophiae Doctor - PhD / Tooth-whitening or tooth-bleaching has become an integral part of modern dental practice. Today, a large number of whitening products are available on the market which are commonly categorized into dentist-supervised home bleaching, in-office bleaching and over-the-counter bleaching products according to their mode of application. This thesis looks into safety and efficacy of various tooth-whitening products and methods. / South Africa