Keratocystic odontogenic tumour: reclassification of the odontogenic keratocyst from cyst to tumour.

The purpose of this paper is to review the features and behaviour of the odontogenic keratocyst (OKC), now officially known as the keratocystic odontogenic tumour (KCOT); to analyze a series of histologically confirmed KCOT cases; and to review and discuss the redesignation of KCOT and the implications for treatment. Redesignation of the OKC as the KCOT by the World Health Organization (WHO) is based on the well-known aggressive behaviour of this lesion, its histology and new information regarding its genetics. Abnormal function of PTCH, a tumour suppressor gene, is noted to be involved in both nevoid basal cell carcinoma syndrome and sporadic KCOTs.

A preliminary radiographic study of mandibular para-radicular third molar radiolucencies.

Objectives: To determine the frequency and describe a poorly documented radiographically observed variation of normal associated with the roots of mandibular third molars--the mandibular third molar para-radicular radiolucency (MPR).

Study Design: A systematic random sample of 822 dental school surgery and emergency charts was reviewed for radiographic evidence of the MPR. The frequency was determined and the variation in radiographic appearance was described.