Imaging characteristics of Gubernacular Tract on CBCT- A pictorial review

The Gubernaculum Dentis (GD) is an anatomical structure connecting the dental follicle of the permanent tooth to the overlying gingiva. It is composed of Gubernacular cord (GCo) and a surrounding bony canal called as Gubernacular canal (GC) or Gubernacular Tract (GT). GD is a physiologic structure that has claimed to play some role in the eruption of teeth. GCo is a histologic structure, however, the surrounding GT can be identified radiographically. But due to its infinitesimal appearance, its differentiation with normal bone marrow spaces on conventional radiographs is extremely difficult and is the reason for its sporadic reference in the oral radiology literature. The advent of advanced imaging modalities such as Cone Beam Computed Tomography (CBCT) has led to its distinct identification in the recent studies not only in the normal erupting teeth but in teeth with altered eruption pattern, impacted teeth, supernumerary teeth, odontogenic cysts and tumors as well. The identification of GT on CBCT is usually an incidental finding and because of its physiologic nature, the imaging characteristics of GT have not been studied extensively. This pictorial review aims to demonstrate the imaging characteristics of GT in diverse relations with the normal teeth, impacted teeth, supernumerary teeth, odontomas and odontogenic cysts and tumors. This will help in understanding the various presentations of GT and will serve as a teaching guide for oral and maxillofacial radiologists for their easy identification and their possible causal association with various eruptive pathologies.