Panoramic Radiology of Pericoronal Pathoses

Abstract

Panoramic radiography has a role in supporting the detection and delineation of pathological conditions in the jaws. This chapter concentrates on the detection and differential interpretation of conditions arising in association with the crown of a tooth or teeth.

The crowns of unerupted teeth are normally surrounded by the dental follicle, a remnant of the enamel forming organ that is lined by reduced enamel epithelium. The enamel follicle is necessary for tooth eruption. The follicle appears as a homogeneous radiolucent halo surrounding the crown of the tooth, arising in the region of the enamel-cemental junction [1]. This “halo” has a thin outer radio-opaque border that is continuous with the lamina dura surrounding the periodontal ligament space. The follicle space can vary considerably under normal conditions and tends to enlarge during tooth eruption. Guidelines to differentiate between a normal and an abnormal dental follicle space include: pericoronal space exceeding 2.5 mm for teeth other than maxillary canines on periapical radiographs or 3 mm in panoramic radiographs [2], or follicular radiolucency exceeding 2.5 cm.