A comparison of morphological traits in deciduous and permanent dentitions

Morphological traits in the deciduous dentition have been understudied compared to their permanent counterparts. Reasons the primary teeth are not as intensely studied include: 1) there is no scoring standard, 2) they are often found in lower frequencies than permanent teeth, and are more subject to wear, and 3) the relationship of development of traits between the deciduous and permanent dentitions is still unknown. This study examines the third problem by comparing frequencies of traits found in both types of teeth within and between two groups. The first sample is from a collection of Pima casts collected by the Dahlbergs approximately 50 years ago. The second is ah archaeological Nubian sample dating primarily to the Meroitic period (ca. 400BC-350AD). Twelve comparable crown traits were examined on fifty individuals with deciduous teeth and fifty individuals with permanent teeth from each group. The primary teeth were scored using a combination of visual and written descriptions based on A.A. Dahlberg and K. Hanihara, in conjunction with the Arizona State University Dental Anthropology System (ASU DAS). The permanent teeth were scored according to the ASU DAS. The results of the study indicate that most traits have comparable frequencies but certain traits, including cusp 7, have significant differences. These differences may be a result of the scoring method used, of perhaps a difference in development. With a refinement in scoring procedures and a standard method, the deciduous dentition of subadults can be used in dental morphology research to increase our knowledge of the people we are studying.