Extraction of the tooth #15 with short clinical crown (suggesting bruxism, Fig.1) reveals a vertical root fracture (Fig.2 <).  It seems unnecessary and difficult to create osteotomy in the mesial slope.  What can be done is to place starter and 2 mm drills as mesial as possible (Fig.3 (red dashed line: sinus floor).

No 3rd Molar Extraction Last Next

Xin Wei, DDS, PhD, MS 1st edition 08/29/2017, last revision 02/17/2019