摘要：It is important for anatomists as well as for anthropologists to identify humanisolated teeth as to where it was located in the jaws that is to say to diagnose the kind of teeth. However, the limit of the possibility in morphological identification has been neither discussed nor examined whatever. The authors of the present paper performed an experiment on this problem in order to clear up how far it goes and whether there is any differences in easiness among kinds of tooth or in capacity among examiners. All of the present authors took part in the experiment, but one of them was absent at the beginning period. Five out of seven are specialists in dental anatomy and others are physical anthropologists. Materials consisted of 3496 isolaeed teeth extracted from 500 Japanese cadavers. Their original site in the dental arches had been recorded, but was kept unknown to the examiners. The essential points of the results obtained are as follows :1) The mean frequency in correct denomination was 89.9% while that of five dental anatomists was 92.0% (Table 1).2) The mean value through all kinds of teeth varied from examiner to examiner, the maximum being 92.6% and the minimum 83.1%. On the other hand the mean value through all examiners varied from tooth kind to tooth kind, the maximum being 95.5% in the upper first premolar and the upper canine and the minimum 74.1% in the lower first incisor (Table 1). This makes it clear that examiner's proficiency has much influence on his judgement, and that all kinds of teeth could not be identified with same easiness.3) Misjudgement of the "numerary order" in the dental arches was found to be most frequent, that of the "side" (right or left) to which the tooth belongs was intermediate and that of the "jaw" (upper or lower) was rather rare (Fig. 2). But each examiner showed different characteristics in the way of misjudgement.4) Such teeth that showed high mean value of correct denomination, e.g. the upper first premolar, may have so distinct morphological features or their criteria for identification may so easily be learned by anyone, that the examiner's proficiencywould have little influence on the judgement. In case of those having low meanvalues, e.g. the upper second molar, however, everything is contrary, i.e. the diagnosis seems to be strongly influenced by the examiner's proficiency.5) In every kind of teeth, the exceptional tooth with atypical details in external shape could take place, the incidence of which is, however, not so frequent. The correct denomination of such tooth is almost impossible even for the experienced dental anatomists.6) The proficiency of identification or the reliability of diagnosis of each examiner should be discussed basing not only upon values in correct diagnosis percentage in examined teeth (Table 1, Fig. 1), but also upon values of correct diagnosis percentage in each denomination (Table 4, Fig. 3).
