Upper ejector rod was added in the die structure for ease of workpiece separation .

在模具结构中增加了 上项杆（ 上打料棒）， 便于工件脱离。

Clinical cause analysis of oroantral fistula after the upper third molar extraction report of one ease

上颌第三磨牙拔除致上颌窦穿孔临床分析&附1例报告及文献 复习