Imaging peculiarities of gubernaculum tracts in molars as accessional teeth on CT

Abstract

Objectives: The shapes of gubernaculum tracts (GTs) in molars as accessional teeth remain unidentified. To elucidate imaging peculiarities of GTs in molars with aging on multidetector-row computed tomography (MDCT).Material and methods: This retrospective study was conducted using CT images, including maxillary and mandibular molars, with no abnormal findings from 239 patients. Shapes of alveolar bone, GTs, and dental sacs of the maxillary and mandibular molars were analyzed multi-sectionally. Correlations between 2-and 3-dimensional imaging figures of GTs in molars and chronological age or stage of molar formation were analyzed.Results: Some forms of GTs in maxillary and mandibular third molars were observed.In the early stage, GTs were visualized as bone defect lines on the dentition and grooves on the mesial alveolar crest continuous with the dental sac to mesial tooth bud. GTs of the third molar formed a J-shape in maxillary teeth and Y-shape in mandibular teeth in the middle stage, as alveolar bone around the GT developed. In the mature stage, the course of the GT changed to straight and perpendicular. Some GT forms were also identified in first and second molars. Significant correlations were found between GT alterations and chronological age or stage of molar formation.Moreover, tracts continuing from the distal side of mandibular third molars were detected.Conclusions: This paper describes the peculiarities and process of progression for GTs in molars, and the existence of tracts continuing from the distal side of mandibular third molars, unlikely dentition with deciduous predecessors. These preliminary data should prove beneficial for studies focusing on GTs in molars.

Overview of Radiological Studies on Visualization of Gubernaculum Tracts of Permanent Teeth

“…The GTs in the maxillary and mandibular molars as accessional teeth are known to be larger than those in the anterior teeth [12,16]. Other GT peculiarities can be observed in the molar region, including the alteration of the GT form of the maxillary and mandibular third molars (Figures 2 and 3) [16].…”

“…The GTs in the maxillary and mandibular molars as accessional teeth are known to be larger than those in the anterior teeth [12,16]. Other GT peculiarities can be observed in the molar region, including the alteration of the GT form of the maxillary and mandibular third molars (Figures 2 and 3) [16]. In the early stage, the shape of the GT is a that of a groove on the mesial alveolar crest that runs continuous with the DS to the mesial tooth bud (Figures 2A and 3A).…”

“…This peculiarity, the way in which the GT in the molar is not perpendicular to the alveolar crest before the mature stage, reflects embryological features. Another notable peculiarity in the mandibular molar region is the "pseudo-GT" that extends from the distal side of the mandibular third molars (Figure 3D) [16]. The pseudo-GT tends to disappear with age without generating a fourth molar.…”

“…In addition, our research group has conducted detailed analyses of the relationship between abnormal tooth eruption and curved/constricted GTs and major odontomas occurring in the GT or dental sac (DS) [13][14][15][16]. We reported that the imaging characteristics of GTs at the top of odontogenic and non-odontogenic masses were useful for differential diagnoses [13][14][15][16]. Subsequently, radiological studies on GTs, including our previous reports, began receiving more attention [5,6,[17][18][19][20].…”

“…Our previous study was the first to describe and analyze the imaging characteristics of the GT [12]. In addition, our research group has conducted detailed analyses of the relationship between abnormal tooth eruption and curved/constricted GTs and major odontomas occurring in the GT or dental sac (DS) [13][14][15][16]. We reported that the imaging characteristics of GTs at the top of odontogenic and non-odontogenic masses were useful for differential diagnoses [13][14][15][16].…”