IADR Abstract Archives
The Relationship Between Impacted Mandibular Third Molars and the Inferior Alveolar Nerve Canal: A Comparative Study of Cone-Beam CT and Panoramic Radiography
Objectives: It is important to examine the position of the impacted third molar and determine its relationship with the mandibular canal preoperatively to minimize the risk of nerve injury. Panoramic radiographs are most commonly used for this purpose. However due to the limitations of two dimensional imaging methods, cone-beam CT (CBCT) examination is recommended for the further investigation.The aim of this study was to evaluate the relationship between the mandibular canal and impacted mandibular third molars using CBCT and to compare the CBCT findings with signs of digital panoramic radiographs (DPR).
Methods: This retrospective study consisted of 200 mandibular third molars from 200 patients who showed a close relationship between the mandibular canal and third molars on DPRs and were referred for the examination of the position of the mandibular canal with CBCT. DPRs were evaluated for the interruption of the mandibular canal wall, darkening of the root, diversion of the mandibular canal, and narrowing of the root. The statistical correlations between the DPR and CBCT findings were examined using the Chi-square test.
Results: The sample consisted of 124 females and 76 males; ages ranged between 18 and 47 years (mean 25.75±6.15 years). 146 cases (73%) showed absence of canal cortication between the mandibular canal and impacted third molar on CBCT images. It was found that there was statistically significant relationship between CBCT and DPR findings (p=0.024, p<0.05). The absence of canal cortication on CBCT images was most frequent in the DPR signs of ‘diversion of the mandibular canal’ (%96) and was least frequent in ‘interruption of the mandibular canal wall’ (65%).
Conclusions: CBCT examination is highly recommended when ‘diversion of the mandibular canal’ is observed on DPR images to reduce the risk of mandibular nerve injury more than other DPR signs.
Methods: This retrospective study consisted of 200 mandibular third molars from 200 patients who showed a close relationship between the mandibular canal and third molars on DPRs and were referred for the examination of the position of the mandibular canal with CBCT. DPRs were evaluated for the interruption of the mandibular canal wall, darkening of the root, diversion of the mandibular canal, and narrowing of the root. The statistical correlations between the DPR and CBCT findings were examined using the Chi-square test.
Results: The sample consisted of 124 females and 76 males; ages ranged between 18 and 47 years (mean 25.75±6.15 years). 146 cases (73%) showed absence of canal cortication between the mandibular canal and impacted third molar on CBCT images. It was found that there was statistically significant relationship between CBCT and DPR findings (p=0.024, p<0.05). The absence of canal cortication on CBCT images was most frequent in the DPR signs of ‘diversion of the mandibular canal’ (%96) and was least frequent in ‘interruption of the mandibular canal wall’ (65%).
Conclusions: CBCT examination is highly recommended when ‘diversion of the mandibular canal’ is observed on DPR images to reduce the risk of mandibular nerve injury more than other DPR signs.