To prevent the drifting, the crown of the tooth is removed (Fig.8).  A guide is fabricated with 12 mm offset so that after bone trimmer (Fig.9 pink), the following drills have more contact with metal sleeve.  Furthermore the drills will have less chance of buccal shifting because of the presence of the root.

Keep Roots     Last     Next Xin Wei, DDS, PhD, MS 1st edition 06/16/2020, last revision 06/16/2020