上颌前部骨内埋伏多生牙视差定位法投照方向的比较研究

The optimization of direction of the horizontal tube shift in the horizontal parallax method to detect the impacted supernumerary tooth

目的:视差定位法球管水平倾斜方向的优选化。方法:在投照方向的选择上,将多生牙分别模拟植入右上切牙区、左上切牙区与中线区共3个区,X线球管水平方向分别作"右→左"及"左→右"倾斜投照,所得的结果用双盲法阅片比较与统计学分析。结果:①对右上切牙唇、腭侧之埋伏多生牙,定位投照时球管倾斜方向选择"右→左"倾比"左→右"倾好,差异有高度显著性(P<0.01);②对左上切牙唇、腭侧之埋伏多生牙,定位投照时球管倾斜方向选择"左→右"倾比"右→左"倾好,差异有高度显著性(P<0.01);③对正中线上2中切牙牙根间的多生牙,定位投照时球管倾斜方向不影响影像质量与定位结果。结论:用视差定位法为上颌前部骨内埋伏多生牙作定位投照与诊断时,对左、右上切牙唇、腭侧的埋伏多生牙,X线球管水平倾斜方向左、右侧应有不同;对11牙根之间的埋伏多生牙,球管水平倾斜方向不会影响影像质量与定位结果。

Objective：To optimize the direction of horizontal tube shift in the horizontal parallax method.Methods：Three skull specimens were included in this study.Supernumerary teeth extracted were implanted into the maxillary incisal region.Two films were used in sequence.The first film was exposed regularly.The second film was placed as possible to the same position as the first one and the tube was moved to the different horizontal projection direction.The localization results were statistically analyzed.Results：①If the impacted supernumerary tooth was in the right maxillary incisal region,it was better that the tube was moved to project from a right distal direction.There was significant difference between the imaging quality results.②If the impacted supernumerary tooth was in the left maxillary incisal region,it was better that the tube was moved to project from left distal direction.There was significant difference between the imaging quality results.③If the impacted supernumerary tooth was in the central line,direction of the tube horizontal shift had no effect on the localization.Conclusion：In the horizontal parallax method,proper projection direction plays a crucial role in imaging quality.