1.The relative location between the mandibular third molar and inferior alveolar canal studied by CBCT
Yunpeng DING ; Shengjiao LI ; Hanyu QIAN ; Jianping ZHOU ; Li ZHANG ; Keji ZHU ; Xuetao WANG ; Lingxia KONG ; Xiaoming CHEN
Journal of Practical Stomatology 2018;34(1):113-116
Objective: To determine the positional relationship between impacted mandibular third molar(IMTM) and mandibular canal(MC) by CBCT. Methods: 664 IMTMs with root apexes contacted to MCs on panoramic radiograph were further examined by CBCT,the exact positional relationship between IMTMs and MCs was observed and analyzed by I-Dixel software. Results: The 664 cases were divided into lowly(6. 3%),intermediately(60. 7%) and highly(33. 0%) impacted groups by the depth of IMTMs in mandibulae showed on CBCT images. The distance(mm) from the root apexes of IMTMs to the intact superior wall of MCs(n = 329) in lowly, intermediately and highly impacted cases were 1. 39 ± 1. 38,1. 28 ± 1. 03 and 1. 79 ± 1. 54 respectively(P < 0. 05). MCs on the buccal side,lingual side,under the IMTMs and between the root apexes were found in 49. 8%,12. 0%,36. 6% and 1. 5% of the cases; the MC wall deffect was found in 65. 8%,27. 5% and 95. 0% of the cases with the MCs under,on buccal and lingual side of the IMTMs, respectively(P < 0. 001). Conclusion: CBCT examination is necessary for the determination of the positional relationship between MC canal and IMTM with the root apex cotacted or overlapped to MC.