Treatment planning of surgical access to the impacted 7 (Fig.1) before CT analysis include extraction of 8 (Fig.2) and removal of the bone coronal to 8 (Fig.3 red) so that there will be no bony block to 7 eruption (Fig.4).  Place PRF in 8 socket to facilitate healing (Fig.3).  Attach a retraction chain to the occlusal surface of 7.  能不能截骨（图三：红色）后，用手术方式把阻生牙移植上提（图四：箭头）？

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Xin Wei, DDS, PhD, MS 1st edition 06/28/2020, last revision 01/10/2021