Objective: The purpose of this study is to investigate the effect of nano-hydroxyapatite (nHA) after teeth extraction. on maintaining the height of alveolar ridge.

• 摘要目的：研究拔牙后即刻植入纳米羟基磷灰石颗粒预防术后牙槽骨吸收，保持牙槽嵴高度的临床疗效。