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