中华口腔医学研究杂志(电子版) ›› 2014, Vol. 8 ›› Issue (03) : 236 -240. doi: 10.3877/cma.j.issn.1674-1366.2014.03.011 × 扫一扫
临床研究
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通信作者:
Lang Liu1, Hong Wu1,†(), Yansong Yu1, Jieyin Li1
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刘朗, 伍虹, 余艳崧, 李洁银. 偏移投照技术用于显示上颌第一磨牙近中颊根第二根管[J/OL]. 中华口腔医学研究杂志(电子版), 2014, 8(03): 236-240.
Lang Liu, Hong Wu, Yansong Yu, Jieyin Li. Clinical usage of angulated radiography technology for detection of the second mesiobuccal root canal of maxillary first molars[J/OL]. Chinese Journal of Stomatological Research(Electronic Edition), 2014, 8(03): 236-240.
目的
探讨数字化成像系统对上颌第一磨牙近中颊根第二根管（MB2）偏移投照的最佳显示效果和拍摄方法。
方法
选取临床上需要进行上颌第一磨牙牙髓治疗并具有MB2 根管特征的患者200 例。 在分角线投照法的基础上，以转动轴作标记记录水平角度，其中100 例从远中至近中每偏移10°进行投照，50 例使用不同的曝光时间，50 例平移传感器位置进行投照。 由两位医师独立阅片，判断牙根区分情况、清晰度及构图完整性。 采用SPSS 16.0 软件包进行配对计数资料的χ2检验。
结果
在MB 与MB2 区分率中，远中偏移30°组最高，区分率为94%，显著高于正位组的10%（χ2=84，P=0.000），相同偏移角度远中偏移比近中偏移区分率更高（30°：χ2=18.382，P=0.000；20°：χ2=16.282，P=0.000；10°：χ2=14.019，P=0.000）。 根尖清晰度方面近中偏移比远中偏移低（30°：χ2=7.848，P=0.005；20°：χ2=12.033，P=0.001；10°：χ2=14.700，P=0.000）。 当近中偏移超过20°、曝光时间增加1/4时清晰率可达78%，传感器的平移摆放使牙体及根尖区的完整显示率达94%。
结论
要获得良好的MB2 显示效果，X 线中心线向远中偏移为首选，若选择向近中偏移则需加大偏移角度和曝光时间，传感器的正确摆放也是直接影响图像质量的关键。
Objective
To evaluate the usage of angulated radiography technology in periapical film of MB2 root canals maxillary first molars and seek better shooting method using digital imaging system.
Methods
Two hundred maxillary first molars with MB2 root canal were selected from clinical case. Radiographs of 100 teeth were taken with every 10 degrees from distal to mesial direction by bisecting angle technique. Meanwhile， radiographs of 50 teeth were taken with different exposure time，while the other half were taken with different position of sensor. The radiographs were identified and recorded by 2 independent doctors. Data of discriminant rate， clarity and integrity of radiographs were analyzed by Chi-square test using SPSS 16.0.
Results
Discriminant rate of MB and MB2 of radiographs taken by 30 degrees from distal direction was the highest （94%）， which was significantly higher than that of orthotopic radiographs （10%）（χ2=84，P=0.000）. With the same angular， discriminant rates of radiographs taken from distal direction were better than mesial direction （30°：χ2=18.382，P=0.000；20°：χ2=16.282，P=0.000；10°：χ2=14.019，P=0.000）. Clarity of radiographs taken from distal direction were aslo better than mesial direction （30°：χ2=7.848，P=0.005；20°：χ2=12.033，P=0.001；10°：χ2=14.700，P=0.000） and the clarity were 78%， when radiographs were taken by more than 20 degrees from mesial direction increasing exposure time by 1/4. The change of position of sensor may improve integrity of radiographs 94%.
Conclusions
Taking radiographs from distal direction is the best way to show MB2. If taking radiographs from mesial direction， the angular and exposure time should increase. The position of sensor should be considered as an important factor which influences the quality of image directly.