Topographic relationship between root apex of mesially and horizontally impacted mandibular third molar and lingual plate: cross-sectional analysis using CBCT

Abstract

The present study was aimed to determine the topographic relationship between root apex of the mesially and horizontally impacted mandibular third molar and lingual plate of mandible. The original cone beam computed tomography (CBCT) data of 364 teeth from 223 patients were retrospectively collected and analyzed. The topographic relationship between root apex and lingual plate on cross-sectional CBCT images was classified as non-contact (99), contact (145) and perforation (120). The cross-sectional morphology of lingual plate at the level of root apex was defined as parallel (28), undercut (38), slanted (29) and round (4). The distribution of topographic relationship between root apex and lingual plate significantly associated with gender, impaction depth, root number and lingual plate morphology. Moreover, the average bone thickness of lingual cortex and distance between root apex and the outer surface of lingual plate were 1.02 and 1.39 mm, respectively. Furthermore, multivariate regression analyses identified impaction depth and lingual plate morphology as the risk factors for the contact and perforation subtypes between root apex and lingual plate. Collectively, our findings reveal the topographic proximity of root apex of impacted mandibular third molar to the lingual plate, which might be associated with intraoperative and postoperative complications during tooth extraction.

Pattern of Mandibular Third Molar Impaction and Relationship to the Inferior Alveolar Canal: Retrospective Cone Beam Computed Tomography Analysis in a Group of Sri Lankan Patients

“…Tooth arch size discrepancy leading to inadequate space for the eruption of IMTM had been identified as most common cause for this phenomenon. IMTM may associate diversified clinical presentations and pericoronitis, swelling in the region, associated odotogenic cysts and tumours, bone resorption and resorption in adjacent tooth are some of them [5]. Such complications are usually associated with impaired oral functions and further leading to discomfort [5].…”

“…Surgical site infection, limitation in mouth opening and neurological complications such as damage to inferior alveolar nerve and lingual nerve are commonly encountered. Further fracture of lingual plate, dislodgement of root pieces in to facial spaces, mandibular fractures, infections in submandibular and pterygomandibular spaces are rarely seen in the clinical practice [5][6][7].…”

“…In surgical perspective review of literature highlights several important aspects to consider in assessment of impacted mandibular third molar. Surgical technique, method of anesthesia, patient age, position of the third molar, angulation and depth of impaction, relationship between the mandibular canal and the third molar, Curvature and other morphological aspects of roots and Shape of inferior alveolar canal were considered to be the factors that influential in predicting nerve damage [5][6][7].…”

Risk Factor in Endodontic Treatment: Topographic Evaluation of Mandibular Posterior Teeth and Lingual Cortical Plate Using Cone Beam Computed Tomography (CT)

“…The current study evaluated the spatial position of the root apices of mandibular posterior teeth relative to the inner edge of the mandible. According to the literature, there is a limited number of relevant studies, mostly focused on impacted third molars in terms of extraction complications [ 6 , 15 , 16 ]. Some early studies on dry human skulls [ 2 , 5 , 17 – 19 ] aimed to assess the prevalence and distribution of root fenestrations in teeth.…”

“…The morphological shapes of lingual plate on the cross-sectional images of each tooth region from the first premolar to the third molar were classified as 4 subgroups according to the classification described by Wang et al [ 15 ]: Type U, undercut on the lingual side; Type P, parallel to the buccal plate; Type S, slanted with buccolingual width reduced on the lingual side; and Type R, round shape on the lingual side ( Figure 3 ).…”