磨牙牙冠大面积缺损临床上十分常见，单纯的根管桩固位，无论用何种充填材料进行修复都难以恢复牙体外形并形成良好的固位型与抗力形。为了尽可能地保存患牙，改善、提高患牙的咀嚼效率，我科从１９９０１２～１９９８１２，采用根管螺纹钉根管内固位并在钉与钉之间结扎丝 Dental crown large area defects are clinically very common, simple root canal pile retention, no matter what kind of filling material for repair are difficult to restore the tooth contour and the formation of a good retention and resistance shape. In order to save the teeth as much as possible to improve and improve the chewing efficiency of teeth, our department from 1990  12 ~ 1998  12, the use of root canal screw nail root canal fixation and ligation between the nail and nail wire