Prevalence of impacted third molar teeth in the greater Durban Metropolitan population.

Abstract

Tooth impaction is a pathological condition in which a tooth is completely or partially unerupted and positioned against another tooth, bone or soft tissue, thus preventing further eruption. Many theories have been proposed to explain the prevalence of impacted third molars. These theories discuss relationship of jaw size to tooth size which is suggested to result from difference in genetics and dietary habits, as the latter differs from one region to another. The aim of this study is to investigate the prevalence of an impacted third molar tooth on a mixed population in the Greater Durban Metropolitan area. The third molar was classified using Winter’s and Pell and Gregory’s classification schemes. Various morphometric parameters of the mandible were measured and assessed in 320 digital panoramic radiographs (n=640). Each parameter recorded was statistically analyzed, using SPSS, to determine if a relationship existed between the aforementioned parameters and sex and age of each individual. 77.9% of cases presented with at least one impacted third molar, with the most prevalent type of impaction being mesio-angulation in the mandible and vertical angulation in the maxilla. In respect to the level of impaction, class IIB and class A was most frequent in the mandible and maxilla, respectively. For correlation with sex, only the length of the mandibular ramus was statistically significant (p-value=0.000). No statistically significant relationship was found between each morphometric parameter and age. However, these results correlated with previous studies indicating that impacted third molars are most prevalent in individuals between 20-25 years. In addition, all morphometric parameters in this study differed from that recorded in previous studies conducted in the Northern Hemisphere. The findings of this study may assist maxillofacial surgeons, dentists, anatomists, anthropologist and forensic investigators.