用常规X线牙片很难完整摄出水平阻生齿的根部，而照一张曲面体层片又浪费胶片。作者设计一种用曲面体层机局部投照法，不但节省胶片，也能清晰显示出阻生齿的全部情况，现介绍如下。一、制作X线胶片定位框取一张15cruX30cmIH胶片，用笔画成左右两等份。再把每份分成9等份，在左 With conventional X-ray teeth is difficult to completely take out the roots of the level of impacted teeth, and according to a curved surface body layer and waste of film. The author designed a local surface layer machine with surface projection method, not only save film, but also can clearly show all the resistance of the tooth, are described below. First, the production of X-ray film positioning box Take a 15cruX30cmIH film, using strokes into two equal parts. Divide each serving into 9 equal parts, on the left