X线平片加大垂直角投照法诊断上颌前磨牙双根作用的评价

Study of radiographic method of increasing vertical angle for identifying double root in maxillary premolar with cone-beam CT

目的:应用锥形束CT(cone-beam computed tomography,CBCT)探讨X线平片加大垂直角投照法鉴别上颌前磨牙双根的可行性。方法:选取上颌牙需做CT检查的患者31例,上颌前磨牙患牙共109颗。在CT三维重建影像上测量患牙牙根的实际径值及在水平角38.5°和垂直角为45°时的牙根投影值并对比分析。采用SPSS12.0软件包对数据进行t检验。结果:上颌前磨牙根尖实际宽度(3.74±0.22)mm与投影宽度(3.69±0.16)mm接近,无显著差异(P>0.05);牙根中1/3水平截面颊舌向实际宽度(7.87±0.66)mm与CT投影测得值(7.95±0.52)mm接近,无显著差异(P>0.05)。结论:锥形束CT为上颌前磨牙双根鉴别X线平片加大垂直角投照法提供了理论依据。

PURPOSE： To explore the feasibility of radiography method of increasing vertical angle for identifying double root in maxillary premolar with cone-beam computed tomography（CBCT）.METHODS： Thirty-one patients with 109 maxillary premolars who needed CT scan for maxillary teeth were selected and scanned by CBCT.The interested region was chosen to reconstruct the image of maxillary premolar at axial,coronal and sagittal section.The actual diameter of root in maxillary premolar and the projection diameter at the center vertical angle of 45° and horizontal angle of 38.5° were measured with CBCT.The data was analyzed with SPSS12.0 software package for Student’s t test.RESULTS： There were no significant differences between the actual diameter of double root tip which was（3.74±0.22）mm and projection diameter which was（3.69±0.16）mm of maxillary premolar at the central vertical angle of 45° and horizontal angle of 38.5° with CBCT（P〉0.05）;There were also no significant difference between the actual diameter of middle 1/3 section of buccal-lingual diameter（7.87±0.66）mm and projection diameter（7.95±0.52）mm of maxillary premolar at the center vertical angle of 45° and horizontal angle of 38.5° with CBCT（P〉0.05）.CONCLUSION： CBCT can provide an evidence for radiographic method of increasing vertical angle for identifying double root of maxillary premolar. Suppoaed by NationalNatural Science Foundation of China（81141012）,Natural Science Foundation of Beijing Municipality（7123228） and Science and Technology New Star Program of Beijing Munieipality（2011120）.