Objective:To appraise the obturation capability of bonded vertically fractured posterior tooth using 3 different detin adhesive by microleakage tests and scan electron microscopy(SEM) observation.

通过染料渗透实验和扫描电镜观察对三种牙结剂结离体纵折后牙进行微渗漏测试，评价封闭能。

The relapse of orthodontically rotated teeth can be a serious problem in occlusal stability after orth-odontic treatment.

扭转牙的复发是正畸临床治疗后牙的难题之一。

To measure the palatal vault in buccal area,which may be helpful to make preadjustment of palatal bar.

研究正畸病人后牙段腭弓形态的规律,为临床预成腭杠的制作提供理论基础。