Third Molar Agenesis in Post-Medieval Chichester

Devyn Caldwell

doi:10.26575/daj.v34i2.306

Abstract

Third molar agenesis is a dental anomaly that occurs in approximately 25% of people worldwide and results in the complete absence of one or more of the third molars in the dentition. A rise in the prevalence of congenitally absent third molars has been noted in modern populations, and it has been proposed as the final evolutionary step in the dental reduction of the human dentition.  Whilst much research has been conducted in modern cohorts, relatively little has been published on third molar agenesis in archaeological assemblages. A post-medieval assemblage from Chichester was visually and radiographically analysed to determine the prevalence of this anomaly. Third molars were measured to determine if there was an association between agenesis and size reduction. Prevalence of agenesis was found to be relatively high at 42.7% and 2 of 8 measurements were found to produce significant differences. Consequently, it can be said that high rates of third molar agenesis are not solely a modern phenomenon, as many prevalence rates in recent populations are lower. However, if we are to assess the significance of size differences in third molars of those with agenesis and those without, and to detect patterns within and between these groups, assemblages with larger sample sizes are needed. In order to better understand the trajectory and evolution of this anomaly, more archaeological assemblages must be examined.

Highlights

Third molars are the last permanent tooth to devel- Bowers et al, 2002), and it is thought that delayed op, the most variable in size and morphology, and growth or a lack of space in the jaw may result in are the most commonly congenitally absent epigenetic absence
Congenital absence is vich, 1981; Garn et al, 1961; Suri et al, 2004), addknown as dental agenesis, which results from a ing to the already complex etiology of this trait
SPSS 21 Statistics software was used to assess falls to 40.2% (n=43/107) and is slightly higher the prevalence of third molar agenesis in the when including those with missing data in two Chichester assemblage and analyze patterns within quadrants at 41.4% (n=48/116) (Table 1)

Summary

Introduction

Third molars are the last permanent tooth to devel- Bowers et al, 2002), and it is thought that delayed op, the most variable in size and morphology, and growth or a lack of space in the jaw may result in are the most commonly congenitally absent epigenetic absence Mice with absent third molars of mice revealed that congenitally third molars more often displayed small and variaabsent teeth begin as tooth germs but growth ble remaining third molars, and as the dental lamiformation ceases at or before the cap stage of na became smaller, the more likely growth and development, at which point the tooth germ tooth formation were to cease development and resorbs. It may occur unilaterally, bilaterally, in resorb. In their meta-analysis of modern data, agenesis occurs more often in modern populations

Findings

Discussion

Conclusion