Implant Placement Level: Coronal

After initial osteotomy at the site of #31 with a 2 mm pilot drill at 11.5 mm, insertion of a parallel pin shows that there is enough clearance from the superior border of the Inferior Alveolar Canal (Fig.1 red dashed line).   One more PA is taken after using 4.3x11.5 mm drill (for 5 mm implant; Fig.2).  A 5.5x11.5 mm implant is incompletely seated (underprep).  The implant is removed; a 4.8x11.5 mm drill is used for 6-8 mm; the implant is re-seated with >50 Ncm (Fig.3).  There are 1-2 threads exposed lingually.  Later autogenous bone is placed over the exposed threads. 

Since there is still enough clearance, the implant should have been removed again.  A 4.3x13 mm should have been used.  The implant should have been placed a little deeper so that there is no thread exposure.  This method also favors restoration at the area with limited vertical height, particularly when the opposing tooth is supraerupted.   In fact this issue is not critical for this case, since the opposing is an implant.

Fig.4 is taken 9 m postop with 7.5x5(3) mm cemented abutment.

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Xin Wei, DDS, PhD, MS 1st edition 06/03/2016, last revision 05/15/2020