Journal of Oral Tissue Engineering

Hardness Variations and Chemical Compositional Canges in Human Cementum

Masaru Yamaguchi1, and Mishima Hiroyuki2
1Ginza Orthodontics Clinic, Tokyo, Japan
2Department of Dental Engineering, Tsurumi University, School of Dental Medicine, Yokohama, Japan

J Oral Tissue Engin 2021; 19(1): 1-9.

This study aimed to analyze the relationship between the hardness and the mineral contents of cementum. From previous research results, fifty extracted premolars were classified as soft, moderate, and hard according to the Vickers hardness test. In this study, six specimens selected randomly in each group were used for the experiments, and three representative premolars in each group of cementum hardness were analyzed.
The hard specimens had more calcium (Ca) content than did softer specimens, according to scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM-EDS). In the element mapping image, magnesium (Mg) was densely distributed in the surface layer of the root apex in the softer specimens. X-ray μCT analysis revealed that the hard specimens had higher tissue mineral density (TMD) than did the other specimens (P<0.01).
The difference in density of Ca and Mg contained in cementum may be related to the variation of Vickers hardness, and may influence the susceptibility to orthodontic root resorption.

Key words: cementum, hardness, tissue mineral density, SEM/energy-dispersive X-ray spectroscopy, Raman analysis

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