Dental Exfoliation and Eruption Chronology in Beagles

¹ Department of Otolaryngology and Maxillofacial Surgery and Department of Orthodontics, University of Iowa, Iowa City, Iowa

Daily observations of deciduous tooth exfoliation and permanent tooth gingival emergence were conducted on 15 male and 12 female purebred Beagles from 5 closely related litters. Central tendency and variability statistics for males and females and for the sexes pooled were derived for postcoital age at deciduous tooth exfoliation, permanent tooth emergence, and interval length betwen exfoliation and emergence. On the average, deciduous teeth were shed between the 176th and 244th postcoital days, gingival emergence of permanent teeth occurred between the 180th and 241st postcoital days, and the interval between the two phenomena ranged from a mean exfoliation precedence of 5 days (mandibular DI1 exfoliation before PI1 emergence) to a mean gingival emergence precedence of 27 days (maxillary PC emergence before DC exfoliation). Significant differences (P< 0.05 in two-tailed tests) were found between males and females in mean age at exfoliation for two of the 14 deciduous tooth classes, and in mean age at gingival emergence in nine of the 21 permanent tooth classes, and between mean exfoliation-emergence intervals in one of the 14 deciduous to permanent exchange classes.