曲面斷層片與錐束CT在分析下頜阻生智齒和下頜管解剖關係中的作用比較

Comparison between panoramic radiography and cone beam CT in analyzing the anatomical relationship between impacted mandibular third molar and mandibular canal

目的通過比較曲面斷層片(panoramic radiography,PR)與錐束CT(cone beam computed tomography,CBCT)在下頜阻生智齒(Impacted mandibular third molar,IMTM)和下頜管(The mandibular canal,MC)的解剖關係分析中的準確性,為臨床工作提供選擇依據。方法選擇2017年12月~2018年5月在鏡湖醫院口腔科就診要求拔除的IMTM患者45例(59顆),拍攝PR與CBCT,由同一名口腔頜面外科醫生依據不同影像資料判定判斷IMTM根尖是否與M C構成接觸關係。拔除阻生齒後即刻檢查拔牙創内下牙槽神經暴露率。採用SPSS 24.0軟件進行統計分析,以χ^(2)檢驗比較依據曲面斷層組、CB CT組及術中的臨床檢查組之間的差異,P<0.05為差異有統計學意義。結果在全部59顆IMTM中,依據PR判斷IMTM和MC相接觸的病例有20顆(33.90%),而依據CBCT冠狀面分析顯示二者相接觸的為8顆(13.56%)。經χ^(2)檢驗後兩組之間有統計學差異。而拔牙後臨床檢查證實二者相接觸的有10顆(16.95%)。拔牙後檢查組與PR組比較有統計學差異;與CBCT組比較無統計學差異。結論在判斷IMTM和MC是否相接觸方面,CBCT比PR具有更高的診斷價值。

Objective To compare the accuracy of panoramic radiography(PR)and cone beam computed tomography(CBCT)in analyzing the anatomical relationship between impacted mandibular third molar(IMTM)and the mandibular canal(MC),in order to provide evidence for clinical practice.Methods 45 patients who underwent IMTM(59 teeth)removal in the OMS&Dentistry Centre of Kiang Wu Hospital were selected for PR and CBCT.The Oral and Maxillofacial Surgeon assessed whether IMTM apex and MC were in contact according to various radiological data.Exposure rate of the inferior alveolar nerve was measured instantly upon extraction of the impacted teeth.SPSS 24.0 software was used for statistical analysis.χ^(2) test was used to compare the differences among PR group,CBCT group and intra-operative clinical examination group.P<0.05 was determined to be statistical significance.Results Among the 59 IMTM cases,20(33.90%)were found to be in contact with MC according to PR,whereas 8(13.56%)were found to be in contact to each other according to CBCT coronal analysis.χ^(2) test showed a statistically significant difference between the two groups.Clinical examination confirmed that 10(16.95%)IMTM were in contact with each other after tooth extraction.There was a statistically significant difference between the clinical examination group and the PR group,however no significant difference among the clinical examination group and the CBCT group.Conclusion CBCT is of higher diagnostic value compared to PR in assessing whether IMTM is in contact with MC.