Abstract
Problem statement: This study investigated the changes in crystallinity and dielectrical properties (conductivity) that could be demonstrated in extracted human teeth (enamel and dentin) subjected to γ-radiation at the sterilization dose (25 kGy). Approach: Twenty human third molar teeth were used in the study. Teeth were prepared so forty enamel and dentin samples were obtained. The samples were divided into two groups. The first group contains twenty samples of enamels. The second ones contains twenty samples of dentins. Each group was further subdivided into two subgroups (10 samples each), one for control while the other for irradiated samples. The X-ray Diffraction Pattern (XDR) studies for the control and irradiated enamel and dentin samples were carried out by X-ray diffractometer. In addition, the microhardness test for the present samples were investigated. Results: The crystallinity in irradiated enamel samples was better than that in dentin where the average crystallite size in enamel was larger than that in dentin. Also, it was found that the dielectrical conductivity for dentin increased with frequency after exposure to γ-radiation. Accordingly, the number and mobility of charge carriers were increased. Conclusion: Exposure of human teeth to gamma radiation at the sterilization dose decreases the hardness of both enamel and dentin.
Highlights
Enamel is the calcified substance that covers the entire anatomic crown of the tooth and protects the dentin
Tooth enamel can be considered as a composite material consisting of 96% inorganic material and 4% organic material and water
The inorganic material is mainly composed of a calcium phosphate mostly in the form of hydroxyapatite, Ca10 (PO4)6 (OH4)2 with different crystallites
Summary
Enamel is the calcified substance that covers the entire anatomic crown of the tooth and protects the dentin. Tooth enamel can be considered as a composite material consisting of 96% inorganic material and 4% organic material and water. Several sterilization methods including autoclaving, chemical heat or dry heat sterilization are common used They might either affect the material properties of the teeth or they are unsuitable for teeth containing amalgam (DeWald, 1997). Gamma radiation has been shown to sterilize non-carious extracted teeth effectively without affecting the material properties if radiation doses up to 2 kGy are used (White et al, 1994). If carious teeth are used, higher radiation doses may be necessary and might cause alterations in material structure and properties. The present study investigated the changes in structural and dielectrical properties of extracted human teeth (enamel and dentin) subjected to γ-radiation at the sterilization dose (25 kGy)
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