全景片下颌管的可视性与下颌阻生第三磨牙关系的临床分析

Clinically study on evaluate the visibility of the superior and inferior borders of mandibular canal using panoramic radiography comparing with the type of impacted mandibular third molar

目的:通过数字成像曲面体层摄影观察全景片下颌神经管的显现率及其与下颌阻生第三磨牙的位置关系,为临床合理拔除下颌阻生第三磨牙,预防下牙槽神经损伤等拔牙术后并发症提供指导。方法:选择需要拔出下颌第三阻生磨牙全景片522颗(464例),图像数字化后处理,直接在电脑显示屏上观察全景片,分析下颌管的显现及其与阻生牙的类型及垂直向关系。结果:大部分下颌管可经曲面体层摄影显现,显现率从后向前逐步降低,下颌管的可见性与阻生牙的类型无统计学差异(P>0.05),与阻生牙的垂直向有统计学差异(P<0.05)。结论:X线曲面体层摄影全景片下颌管的显现率较高,下颌管的显现率与阻生牙的类型没有关系,但与垂直向关系有差异,说明下颌管的可见性较高。对少部分下颌管显现不清,应拍摄CBCT或螺旋CT以明确下颌管的确切部位和走行,以减少拔牙对下牙槽神经的损伤。

Objective：To study the visibility of mandibular canal（MC） using panoramic radiography（PR） comparing with the type of impacted mandibular third molar,so as to use appropriate clinical methods to extract the mandibular third molar and to provide methods for the prevention of the inferior alveolar nerve damage and other complications after tooth extraction.Methods：The panoramic radiography images of 464 patients（522 hemi-mandibles） were chosen,which were presented on a computer after the digitized image processing.And analyze the relationship between the visibility of the MC and the type and vertical direction of impacted tooth.Results：The MC was clearly visible by using PR in most of the hemi-mandibles in third molar regions,the rate of which was gradually reduced back to front.The visibility of the MC on third molar regions was no statistically difference compared to the type of third moalr.There was a significant difference with the vertical to the impacted tooth.Conclusions：The MC was clearly visible by using PR in most of the hemi-mandibles in third molar regions,the rate of which was gradually reduced back to front.The visibility of the MC on third molar regions was no statistically difference compared to the type of third moalr.There was a significant difference with the vertical to the impacted tooth.