Identifying the Polo® mint mandibular third molar: a case series

Abstract

AbstractAimPerforation of mandibular third molars (MTMs) by the inferior dental nerve (IDN) is an uncommon finding. Such cases are thought to carry the highest risk for IDN injury (IDNI) due the entrapment of the nerve within the tooth. This case series aims to highlight the lack of consistency through varying radiographic signs, a perforated MTM may present on 2D imaging.MethodsIn this series, 22 cases of perforated MTMs were identified prospectively by cone beam CT. The plain film radiographic images for these cases were retrospectively analysed to determine if any of the 2D radiographic features could help to identify a perforated MTM.ResultsIn 86% (19/22) of the cases at least three IDNI ‘at risk' radiographic signs were present, 91% (20/22) of the cases superimposition of the IDN canal was seen and in 86% (19/22) of the cases banding of the root was evident. Deviation and narrowing of the canal was only identified in 59% (13/22) of the cases.ConclusionIn this study no single or repeated multiple 2D ‘at risk' sign was predictive of perforation of the tooth by the IDN. Most cases show multiple ‘at risk' signs but there remains no consistency even within these signs.