Secular Change of Dentofacial Morphology during Japanese Historic Ages

Abstract

Dentofacial morphology of Japanese has been continuously altering through the historic ages toward the pattern of the moderns. Concerning the almost monotonous increase of the tooth to denture base discrepancy, this alteration is considered to tend always to reduction. The present paper deals with this secular change of the dentofacial morphology during the Japanese historic ages.
Roentgenographic cephalograms of 95 Japanese skeletal remains from the later Jomon, Kofun, Kamakura, Muromachi and Yedo eras as well as of 288 living Japanese were analysed using 11 linear and 18 angular measurements.
As the results, slight enlargement of the anterior facial height and diminution of the facial depth were observed as a general trend. Diminution of jaw bones was also dominant especially in the height of the mandibular ramus and the antero-posterior dimension of the maxillary and mandibular apical bases. Consequently the degree of forward inclination of the maxillary and mandibular incisors increased, and this seems to be the expression of the tooth to denture base discrepancy.