The author studied the vertical height of tooth crown and the amounts of alveolar bone resorption with age.
All 84 subjects(44 male, 40 female) who visited Dental hospital of Wonkang University with no history of severe periodontal disease and no experience of periodontal surgery. 84 subjects were divided into 3 groups by age, that is, group 1 (28-32vrs), group l] (38-42yrs), and group11(48--52yrs).
In:racral radiogram with bite wing film(horizontal angulation : 0°, vertical angulation : +5°--+10° ) were taken on premolar and molar area.
The distances from cusp tip to cementoenarnel junction (vertical height of tooth crown) and from cementoenamel junction to alveolar crest (amounts of alveolar bone resorption) were measured, and then recorded data from 946 teeth were statistically analysed.
This study was undertaken to obtain the data for age estimation by the changes of tooth crown height and alveolar bone resorption in the point of forensic odoritology. The obtained results were as follows
1. The average crown height of mandibular right 1st molar was 7.1mm in group I. 6.7m in group 11. and 6.6= in group m , and the average amount of alveolar bone resorption on mandibular right 1st. molor were 1.8mm in group I , 2.5mm in group II , and 3.0mm in group M. Ratio of tooth crown height to amount of alveolar bone resorption was 4.0: 1 in group I 2.7:1 in group II , and 22:1 in group
U1, the ratio was decreased with age.
2. In comparison with upper teeth and lowar teeth in ipsilateral side, the average value of tooth crown height and amount of alveolar bone resorption were slightly higher in upper arch than those in lower arch, but there was not a statistically significant difference.
3. The ratio of height of tooth crown to amount of alveolar bone resorption was decreased with age, and which depended mainly upon the change of amount of alveolar bone resorption rather than the change of tooth crown height.
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