Mixed dentition analysis for Asian-Americans.

One of the important aspects of diagnosis in the mixed dentition is the determination of the tooth size-arch length relationship. Such a determination is often made before eruption of the permanent canines and first and second premolars. The most commonly used prediction method of Tanaka and Johnston is based on data from a sample of children of Northern European descent. The accuracy of this method when applied to a different ethnic population is questionable. In this study, 201 dental plaster casts of Asia-Pacific-American subjects, all of whom were under the age of 21 years, were used. The actual measurements were compared with the predicted values derived from the Tanaka and Johnston equations and significant differences were found. The data illustrate the limitations of the Tanaka and Johnston method when applied to a sample population of other than European descent. From this data, two linear regression equations were developed for tooth size prediction in Asian-American children.