Related Experiment Video
Updated: May 9, 2026
Microhardness Measurements on Tooth and Alveolar Bone in Rodent Oral Disease Models
Published on: April 26, 2024
Newly developed hardness testing system, "Cariotester": measurement principles and development of a program for
Akihiko Shimizu1, Syozi Nakashima, Toru Nikaido
1Department of Dentistry and Oral Surgery, Hyogo College of Medicine, Mukogawa-cho, Nishinomiya, Hyogo 663-8501, Japan. shimizu@diary.ocn.ne.jp
Abstract:
We previously discovered that when a cone-shaped indenter coated with paint was pressed into an object, the paint disappeared in accordance with the depth of the indentation. Based on this fact, we developed the Cariotester, a portable system for measuring the Knoop hardness (KHN) of carious dentin. The Cariotester is composed of a handpiece with an indenter, a microscope, and a computer. In this system, the painted indenter is forced into the material with a 150-gf load, and the indentation depth (CT depth) is obtained from the paint disappearance. The CT depth by the Cariotester and the KHN by a microhardness tester were determined at 14 dentin regions. From the data, a program was created to convert the CT depth of the carious dentin into the KHN. As a result, if the CT depth is measured with this system, the KHN of carious dentin can be displayed in real time.
