A digital fourier harmonic superposition method for the structural analysis of human tooth enamel obtained by electron microscopy

• Published in: Micron and microscopica acta 1984, Vol.15 (1), p.17-35
• Main Authors: Kanaya, Koichi, Baba, Norio, Shinohara, Chiharu, Ichijo, Takashi
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; complex scattering amplitude; diffraction spots; Digital processing; Fourier transform; Fundamental and applied biological sciences. Psychology; hexagonal; hydroxyapatite; Mouth. Exocrine and endocrine salivary glands. Teeth. Esophagus; reconstructed image; Vertebrates: digestive system
• ISSN: 0739-6260
• DOI: 10.1016/0739-6260(84)90028-5

A digital processing method with the aid of a scanning densitometer system for image analysis of electron micrographs was successfully applied to human tooth enamel which has been recognized to be composed of hydroxyapatite [Ca 10(PO 4) 6(OH) 2]. Based on Fourier techniques for structural analysis from a computer-generated diffractogram, it was confirmed that specimens from thin sections of the material contained a hexagonal crystal structure which was basically similar to a prototype crystal of hydroxyapatite previously determined by neutron and X-ray diffraction. Some of the known structural features were confirmed but other unknown details were established from a superposition of individual harmonic images formed by the enhanced scattering amplitude and corrected phase which are inversely transformed from the selected diffraction patterns. A model is proposed for the tetragonal pyramids of PO 4 whose hexagonal co-ordinates ( u, v, w) in the unit cell were analytically determined. According to the digital processed data, an equi-contour map representing the precise location and subsequent three-dimensional arrangement of the atoms in human tooth enamel are derived and graphically demonstrated.