title: Comparative efficacy of spiral computed tomography and orthopantomography in preoperative detection of relation of inferior alveolar neurovascular bundle to the impacted mandibular third molar.
abstract: OBJECTIVE
  To assess the relationship of the inferior alveolar neurovascular canal (IANC) and the impacted mandibular third molar on spiral computed tomography (SCT), determine the validity of this assessment, and compare it with that for an orthopantomogram (OPG).
  
  
  METHODS
  Patients visiting the Oral and Maxillofacial outpatient department at the Government Dental College and Hospital, Nagpur, India, were chosen as the subjects for our study. Patients were operated on and the actual clinical findings were compared with the SCT findings. Sensitivity, specificity, and area under the receiver operating characteristic (ROC) curve were determined as a part of ROC analysis. The values for both the diagnostic modalities were then compared using a chi(2) test.
  
  
  RESULTS
  Objective evaluation of the SCT showed that the number of positive clinical findings (marking on tooth surface, visualization of the neurovascular bundle, intraoperative excessive hemorrhage, and IAN paresthesia) were significantly more in patients with no measurable distance between the tooth and the canal. Also, the positive clinical findings were observed significantly more in patients who had the following features observed on spiral CT: lack of cortication of the canal and lingual or intraradicular course of the inferior alveolar neurovascular bundle (IANB). ROC analyses of both these diagnostic modalities have shown that the SCT performed better than OPG, although the difference is not statistically significant (P = .9871; chi(2) test).
  
  
  CONCLUSIONS
  The spiral CT images definitely enhanced the visualization of the relation of the tooth to the IANB, which might provide a higher level of intrasurgical safety and safeguard the interests of both the surgeon and the patient.
authors.affiliation: Oral and Maxillofacial Surgery, Maulana Azad Institute of Dental Sciences, New Delhi, India. mail: draakarsh@yahoo.co.in
authors.forename: Aakarsh
authors.initials: A
authors.lastname: Jhamb
authors.forename: Rameshwar S
authors.initials: RS
authors.lastname: Dolas
authors.forename: Prashant K
authors.initials: PK
authors.lastname: Pandilwar
authors.forename: Sujata
authors.initials: S
authors.lastname: Mohanty
mesh_terms: D000328:Adult; D000368:Aged; D016009:Chi-Square Distribution; D020209:Cranial Nerve Injuries / Q000209:etiology / Q000517:prevention & control; D005260:Female; D006801:Humans; D008297:Male; D008334:Mandible / Q000033:anatomy & histology / Q000000981:diagnostic imaging* / Q000601:surgery; D008340:Mandibular Nerve / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D008875:Middle Aged; D008964:Molar, Third / Q000033:anatomy & histology / Q000000981:diagnostic imaging* / Q000601:surgery; D019647:Oral Surgical Procedures / Q000009:adverse effects; D012372:ROC Curve; D011862:Radiography, Panoramic; D012680:Sensitivity and Specificity; D036542:Tomography, Spiral Computed; D014095:Tooth, Impacted / Q000000981:diagnostic imaging* / Q000601:surgery; D061221:Trigeminal Nerve Injuries; D055815:Young Adult