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Updated: May 22, 2026
Microhardness Measurements on Tooth and Alveolar Bone in Rodent Oral Disease Models
Published on: April 26, 2024
Determination of fracture toughness of human permanent and primary enamel using an indentation microfracture method
Sachiko Hayashi-Sakai1, Jun Sakai, Makoto Sakamoto
1Division of Pediatric Dentistry, Department of Oral Health Science, Course for Oral Life Science, Niigata University Graduate School of Medical and Dental Sciences, 2-5274 Gakkocho-Dori, Chuo-ku, Niigata, 951-8514, Japan. sachipro@dent.niigata-u.ac.jp
Abstract:
The purpose of the present study was to examine the fracture toughness and Vickers microhardness number of permanent and primary human enamel using the indentation microfracture method. Crack resistance and a parameter indirectly related to fracture toughness were measured in 48 enamel specimens from 16 permanent teeth and 12 enamel specimens obtained from six primary teeth. The Vickers microhardness number of the middle portion was greater than the upper portion in primary enamel. The fracture toughness was highest in the middle portion of permanent enamel, because fracture toughness greatly depends upon microstructure. These findings suggest that primary teeth are not miniature permanent teeth but have specific and characteristic mechanical properties.
