Author : Mohamed Nur Abdallah
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (922 download)
Book Synopsis Surface Reactivity of Tooth Enamel with Dyes, Oxidizing Agents and Magnesium Ions and Its Effect on Tooth Color by : Mohamed Nur Abdallah
Download or read book Surface Reactivity of Tooth Enamel with Dyes, Oxidizing Agents and Magnesium Ions and Its Effect on Tooth Color written by Mohamed Nur Abdallah and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Enamel, the outer protective layer of human teeth, is constantly interacting with its surrounding harsh environment. These interactions play a major role in many mechanisms that affect the dental health such as tooth caries, tooth discoloration and plaque formation. Accordingly, most treatments used to maintain and/or restore dental health focus first on the enamel surface. Even though most of the enamel structure has been thoroughly studied, many of the enamel surface features, and the chemical reaction that occur on it, are not well understood. Extrinsic tooth discoloration poses a major problem to many patients and dentists. Most causes of extrinsic tooth staining have been well identified and are usually treated with hydrogen peroxide. However, the mechanism of extrinsic tooth discoloration and tooth bleaching using peroxide oxidizers are not fully understood. It is unknown why certain staining molecules attach to the enamel surface, whether peroxide radicals make teeth whiter by removing these stains, and why sometimes hydrogen peroxide does not work. Also, treating darkened teeth with peroxide agents has its limitations and disadvantages. This has pushed us to look for better and less harmful whitening agents. Recent studies have revealed that there is a correlation between crystallographic characteristics of enamel and its physical properties, such as tooth shade and microhardness. This discovery predicts that tooth properties can be changed by modifying its crystallographic structure. Since magnesium ions are known to react with synthetic hydroxyapatite and affect its crystallographic properties, it is possible that magnesium ions could react with dental enamel and induce changes in dental enamel crystallographic, optical and mechanical properties. Several significant conclusions and achievements are presented in this thesis. We demonstrated the presence of a carbon rich layer on the surface of enamel that contains relatively high amounts of calcium. This layer might explain the high staining ability of certain types of anionic staining agents that are among the most common causes of external tooth discoloration. Moreover, we showed that hydrogen peroxide does not induce significant changes in tooth enamel organic and inorganic relative contents, and it whitens teeth just by oxidizing their organic matrix. This finding is of great clinical significance since it explains the mechanism of tooth bleaching and the reasons behind the limited predictability of the treatment outcomes. Finally, we showed for the first time that magnesium ions can react with tooth enamel and induce a reduction in the size of enamel hydroxyapatite nanocrystals. This change in crystallography affected the enamel optical and mechanical properties; making the enamel harder and whiter. This is a new method that can be exploited to whiten teeth without using peroxide-based bleaching agents. We concluded that crystallographic ultrastructure plays a key role in defining the tooth enamel properties which can be tailored through ionic substitution for improvement of optical and mechanical properties without causing the possible negative effects of peroxide agents." --
