Journal of Dental Research, Vol 56, 117-127, Copyright © 1977 by International & American Associations for Dental Research Online Journals
Dental condition of two tribes of Taiwan aborigines--Ami and Atayal
K. L. Liu
This is a study of dental and oral conditions of Taiwan aborigines from the
epidemiological and anthropological points of view. A total of 166 Ami and
128 Atayal adolescents were included from their original living area, the
Hwa-Lien Hsin and Wa-Lai District, Taiwan, Republic of China. Oral
examination was done carefully and caries incidence, periodontal index, and
Angle's Classification combined with OFI were included. After that,
hydrocolloid impressions were taken, and dental casts were immediately
made. The mesiodistal and buccloingual crown diameters and also the arch
depth and width were measured using a sliding caliper. Dental morphological
traits, such as shovel-shaped incisors, Carabelli's cusp, protostylid, and
upper and lower molar groove patterns were observed and classified, and the
results are given with statistical analysis. The aborigines have a quite
low incidence of dental caries and periodontal disease which may be related
to their dietary habits, good oral hygiene, and good dental occlusion. With
regard to the differences between the Ami and Atayal, most of the date show
no statistical significance except in the dental occlusion. The Atayal's
occlusion is better than that of the differences of genetics or other
factors. There are no sex differences in all the date in the dental survey,
but there are sex differences in both the misiodistal and buccolingual
crown diameters of both the Ami and Atayal tribes (the tooth crown of the
male subjects is invariably broader and larger than that of females). In
the dental arch dimensions, most of the data show no sex diffreence, except
in the breadth of the upper and lower dental arch of the Atayal.
Anthropologically, there are no statistical differences, in mesiodistal
and buccolingual crown diameters and most of the data of dental arch
dimesions, but there is a difference in arch depth in Ami and Atayal
adolescents. The Atayal have a deeper dental arch than do the Ami. As for
dental morphologi, the Taiwan aborigines have a high frequency of
shovel-shaped incisors and Carabelli's trait but a relatively low frequency
of protostylid. There are no definite differences between races in the
occlusal pattern of maxillary first molars, but there are differences in
the maxillary second molars. The usual pattern is 4-- for the upper first
and second molars of the Taiwan aborigines as well as for thedibular
occlusal pattern, the first molar tends to follow the primitive
"dryopithecus" pattern of 5 cusps and Y configuration, but in the second
molar there are varying degrees of departure from Y5 to the more advanced
+4 pattern with +5 and Y4 as intermediates.
