Variant root morphology of third mandibular molar in normal and impacted teeth

Abstract

The mandibular third molar poses a challenge to dental surgeons due to it’s unpredictable morphology which leads to increased difficulty during its extraction. The root morphology of the third molar is considered to be the most variable in the human dentition. The study aims to document these variations which will be useful while undertaking procedures on the third molar. Three hundred and fifty nine panoramic views of the mandible were obtained from the Radiology division for patients seeking treatment in the School of Dental Sciences since 2010. The prevalence of third molar impaction was found to be 27%, with mesioangular being the commonest at 21.9% using the Winter’s classification. Dilacerations of roots was recorded at 44%, with a ratio of normal to dilacerated of 1:1 seen in impacted teeth while, non impacted teeth had a ratio of 1.3:1. Most teeth had 2 roots (85.5%), with one root seen in 12.1%. Partially fused roots was also observed in 2.4% of cases with only one case showing three roots. The total mean distance from the tips of roots to the mandibular canal was -0.5mm. Higher negative means of -1.5mm was recorded in impacted teeth than in normal teeth (-0.2mm). Teeth with dilacerated roots also showed closer proximity to mandibular canal than straight rooted teeth. The left side of the jaw also showed higher negative means. Present findings suggest that careful considerations should be made on impacted teeth. In addition to the type of impaction, proximity to the inferior alveolar nerve (IAN), number of roots and shape of the roots should be assessed. Similar considerations should also be made to non impacted teeth due to the high unpredictability observed in root morphology.

Keywords: Third molar, root morphology, impaction