Narrower implants (as compared to those on the left) are placed (Fig.7: 4.5x12 and 4.5x10 mm at #30 and 31, respectively).  With shorter implants, the implants are later placed deeper (as shown by arrows, red dashed line: the superior border of the Inferior Alveolar Canal) so that almost all of the microthreads are buried in the bone.  It is expected that there is less chance of thread exposure postop.  The later turns out to be true 3.5 months postop (Fig.8 with 6.8x5(3) mm abutments).   It appears that the abutment margin is supragingival (white dashed line: gingival margin) and should be trimmed prior to impression.  Or change the abutments to ones with shorter cuff. 

Sufficient Interocclusal Space

Xin Wei, DDS, PhD, MS 1st edition 04/03/2016, last revision 01/19/2018