Comparative assessment of the crystalline structures of powder and bulk human dental enamel by X-ray diffraction analysis.

ABSTRACT

OBJECTIVES: The aim of this study was to assess and compare the crystalline structures of both powder and bulk human dental enamel by X-ray diffraction analysis (XRD). METHODS: The buccal surfaces of 60 selected noncarious third molars were divided into two groups of powdered and bulk enamel specimens. To prepare enamel powders, the enamel tissues were ground and powdered manually using a mortar and pestle. For bulk samples, the enamel slabs were sectioned using a low-speed diamond saw. The crystalline structures of samples were analyzed by XRD, and the obtained data were analyzed. The values of the lattice parameters were obtained using the equation of hexagonal crystalline structures. The crystal sizes and microstrains of crystallites were calculated using both the Scherrer and Williamson-Hall (W-H) methods. The total area under the peaks was considered as the criterion for assessing crystallinity. The data were analyzed by a parametric independent t-test and nonparametric Mann-Whitney test using SPSS for Windows at a significance level of 0.05. RESULTS: The results of the current study revealed significant differences between the crystallinity values and crystal sizes of the two study groups (p ≤ 0.001). The powdered samples showed higher crystallinity and smaller crystal sizes than those of the bulk samples. The obtained strain values of the powder samples were nearly twice those of the bulk samples. This difference was not statistically significant (p = 0.76). CONCLUSIONS: The results of this study revealed that the sample preparation method for human tooth enamel can affect the crystalline data obtained from XRD analysis.