VARIATIONS IN THE FREQUENCY OF SHOVEL-SHAPED INCISORS IN DIFFERENT POPULATIONS

Abstract

This chapter presents information regarding the frequency of shovel-shaped incisors in ten relatively homogeneous groups of people, namely, Romano-British, Anglo-Saxon (Early British), Danes, Swedes, Norwegian Lapps, Bantu, Arabs, Indians, East Greenland Eskimo, and a combined Japanese, Chinese and Tibetan series. It also presents statistical analysis of the correlation of shovel morphology between the median and lateral incisors. The chapter highlights the incidence of the shovel-trait in earlier forms of man. A major aspect of the study of human dentition is the recognition and assessment of morphological variations. One such characteristic is the presence of structural formations referred to as shovel-shape, manifested by the prominence of the mesial and distal ridges enclosing a central fossa in the lingual surface of incisor teeth, differentiating them from types without the shovel character. Shovel-shaped incisors are frequently found among the upper incisors and occasionally among the lower incisors. Generally, they are bilateral, although in rare instances, they are not. The mode, origin, inheritance, and phylogenetic significance of shovel-shaped incisors are not yet understood, and there is still much data to be collected on the various racial groups. An evaluation of the degree of shovel character is to some extent largely subjective, and discrepancies in results gathered from the same ethnic groups by different workers certainly occur.