الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Summary and Conclusions
Preoperative radiographic assessment of the impacted mandibular third molars is essential to prevent inferior alveolar nerve damage during surgical extraction. This study, assessed the reliability of panoramic signs between the roots of impacted teeth and the canal, and to compare the panoramic signs with cone beam computed tomography (CBCT) findings.
Fifty adult healthy patients with impacted mandibular third molars were selected from the Out Patient clinic of the Oral and Maxillofacial Department, Faculty of Dentistry, Suez Canal University, for surgical removal of one or both impacted mandibular third molars. The studied patients showed a close relationship between the mandibular canal and the third molars on panoramic radiographs. Panoramic radiographic images were evaluated for darkening of the roots, Deflection of the roots, Narrowing of roots, Interruption of white line of canal, Diversion of canal, and narrowing of the mandibular canal. Angulation (vertical, horizontal or mesio- disto angular) and positions (class I, class II or class II) of impacted lower third molar were also evaluated.
All patients were referred for further evaluation using CBCT images to determine the course of each canal and its proximity to the roots, the impacted lower third molar (buccal, lingual, interradicular or inferior), the position of the impacted lower third molar with respect to the IAC (contact, no contact), the morphologic shape of the mandible in the impacted lower third molar region (round, lingual extended, lingual concave). Data were statistically analyzed using Chi-square test to compare panoramic signs with CBCT findings.
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Summary & Conclusions
The results revealed that panoramic examination showed that only Class III (The most inferior portion of the tooth was below the superior border of the IAC) of impacted lower third molar and contact relation between impacted lower third molar and IAC in CBCT examination were significantly associated with inferior alveolar nerve injury.
Within the conditions of this study, the following could be concluded:
Poor reliability of the panoramic predictive signs of the proximity of mandibular third molar roots with mandibular canal in predicting inferior alveolar nerve injury.
Based on the findings of the present study, neurosensory disturbance of the inferior alveolar had relatively low incidence after mandibular third molar extraction, most of which were transient and resolved after 3 months.
CBCT improved our understanding of the relationship between impacted mandibular third molar and inferior alveolar canal previously assessed by panoramic radiography.
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