Correlation of Panoramic Radiographs and Spiral CT Scan in the Preoperative Assessment of Intimacy of the Inferior Alveolar Canal to Impacted Mandibular Third Molars

Abstract

Iatrogenic origin of neurosensory dysfunction is a distressing sequel to the surgical removal of impacted mandibular third molars, which is frequently overlooked. According to various surveys, the rate of neurologic complications related to the surgical removal of impacted mandibular third molars varies between 0.5% and 1% for permanent damage and 5% and 7% involving temporary damage. Prevention always stands as the best modality to avoid patient's discomfort and lawsuits by sophisticated consumerism.Preoperative assessment of the topographic relationship of the impacted mandibular third molar to the inferior alveolar canal has been performed by different imaging modalities. However, none of the imaging techniques give cent percent information. The best available imaging modality in time and resources should be adopted by the surgeon to avoid complications and lawsuits. Orthopantomography has often been cited as the imaging modality of choice before surgical removal of impacted mandibular third molar. However, it depicts a two-dimensional view of an intricate three-dimensional anatomic relationship and also fails to accurately project the buccolingual relation between the tooth and the inferior alveolar canal. The current study was designed to evaluate the potential advantages of spiral computed tomography and compare its efficacy as a presurgical planning tool with orthopantomography in patients with impacted mandibular third molars showing proximity to the inferior alveolar canal on an orthopantomogram.

Mandibular Third Molar Impaction: Review of Literature and a Proposal of a Classification

“…For example, cervical spine images often overlap on the anterior mandible. Furthermore, it depicts a two-dimensional view of an intricate three-dimensional anatomic relationship and also fails to accurately project the buccolingual relation between the tooth and the inferior alveolar canal [30,31]. …”

Correlation of panoramic radiography and cone beam CT findings in the assessment of the relationship between impacted mandibular third molars and the mandibular canal

“…To avoid this problem, many studies have proposed risk factors based on the findings of panoramic radiography. 15,[17][18][19][20][21][22][23][24] However, as a two-dimensional exam, it does not provide specific diagnostic information about the relationship between the third molar and the mandibular canal. Knowledge of this relationship Several studies have demonstrated that the presence of two or more signs on a panoramic radiograph indicates an increased risk of IAN exposure 15,18,20,24,27 or injury.…”

“…These findings conform with those in other studies. 5,16,17,21,25,26 The anatomical proximity of the roots of the third molar and the mandibular canal can result in IAN injuries during the extraction of the third molars. To avoid this problem, many studies have proposed risk factors based on the findings of panoramic radiography.…”

“…Several studies 15,[17][18][19][20][21][22][23][24] that evaluated the relationship between the mandibular canal and the third molar suggest pre-operative evaluation by CT when specific signs are observed in panoramic radiography. In the present study, most panoramic radiographic signs were interruption of white line (20.4%) and darkening of roots (17.4%).…”

“…3 In the present study, we used the most common signs (darkening of roots, diversion of mandibular canal, narrowing of mandibular canal and interruption in white line) associated with a higher risk of IAN injury [15][16][17][18] (Figure 1). On the CBCT images, the presence or absence of corticalization between the mandibular third molar and the mandibular canal was evaluated using cross-sectional images.…”