Biomedical Engineering Reference
In-Depth Information
5.2
Nanohardness and Elastic Modulus
at Different Locations of a Rod of Human Teeth
Human tooth enamel specimens were prepared from freshly extracted human man-
dibular third permanent molars (M
3
) without caries, which were from individuals of
either gender who were between 18 and 25 years of age. The teeth were stored in
distilled water at 4 °C before use.
Five teeth were used in this study. Each tooth was cut into two halves using a
diamond saw along the direction perpendicular to the buccolingual division line. As
shown in Fig.
5.3
, each half of the tooth was embedded into a steel-made mold with
self-setting plastic (10 × 10 × 20 mm in size). One half of each tooth was ground and
polished on the occlusal surface. The process was careful to remove only 0.2-
0.3 mm of each specimen in order to obtain a surface similar to the original occlusal
surface of enamel in the mouth. As a result, five specimens of the occlusal section
were prepared. Specimens were first ground using abrasive papers of 360, 500, 800,
1,200, and 1,500 grit in turn, and then polished with diamond paste from 10, 5, 2.5,
Fig. 5.3
Preparation of the tooth sample: (
a
) a typical human molar; (
b
) the mould to prepare
sample; (
c
) the tooth sample taken out from the mould; (
d
) the tooth sample after polishing
