Methods: Eighty extracted teeth received one of four post systems of stainless steel threads post, titian post, quartz fiber post, and glass fiber post, and then were restored with crowns.

• 方法：选用80颗离体牙，分别用不锈钢螺纹桩、钛桩、石英纤维桩和玻璃纤维桩修复牙根，并制作牙冠。