Biomedical Engineering Reference
In-Depth Information
resistance of human teeth: an ingenious systematic structure, surface engineering,
a compact and orderly microstructure, a bioactive self-repair capacity, and a unique
lubrication system [
136
]. It seems that such a natural dental antiwear system has
integrated almost all antiwear and friction-reducing methods until now. Each of the
factors is of crucial importance and indispensable.
It is no doubt that human teeth have a superior natural wearable system.
Understanding why human teeth possess excellent behavior can provide valuable
insights into bionic design for antiwear engineering systems based on human teeth.
1.9.4
Identification
It is well known that teeth can be preserved for a long time after other human tissues,
including bone, have been disintegrated. The evolution of both the human tooth
surface and internal tissue follows a typical chronological pattern and provides
valuable information on an individual's growth.
Teeth can be a biological marker of aging and have been proposed as a tool of age
estimation. However, some estimation methods require tooth extraction and micro-
scopic examination, and their analyses are not only impractical for live individuals,
but also time-consuming and cost-inefficient. In addition, although other improved
methods such as computer graphics are available, their applications in clinical situ-
ations are considerably limited due to their complex manipulations. Age estimation
by occlusal tooth wear was proposed by Kim et al. [
137
]. The degree of tooth wear
for each tooth was evaluated with the naked eye or a magnifying glass under a light
using the Kim's scoring system of tooth wear. This method is very simple and con-
venient and does not need any invasive processes such as tooth extraction. However,
a low level of accuracy due to individual differences such as eating and chewing
habits and bite force remained to be improved for further clinical application.
In addition, surface profiles of the occlusal contacts are closely related to both
dietary culture and living habits. Tooth wear is an important feature that preserves
direct evidence of the masticatory behavior of mammals, food preparation (such as
hard or soft food, raw or cooked food), cleaning, and use of teeth. Therefore, pat-
terns of tooth wear can be used to make inferences in prehistoric populations and
extinct species. Understanding the wear pattern of teeth is particularly important
from an archaeological point of view in order to illustrate partial evolutions of both
humans and other mammals.
1.10
Summary
This chapter reviews the history of biotribology and focuses on the research involv-
ing the unique material of the tooth. They seem very simple, but the function and
biomechanics of human teeth are much more complicated. From a materials
