As to #30 osteotomy entry point, it tends to start in the middle of a flat surface (Fig.5' white arrowhead), but it is directly underneath the pontic (P).  The trajectory will be not correct.  Ideally the entrance point should be at the crest.  To avoid slippage, a sharp starter drill will be used.  A second advantage is that the osteotomy will be as deep as the previous entry point.  There is less likelihood of nerve (N) injury (Fig.5).

The cancellous bone is low in density.  Osteotomy should be under prepared.  Sequential osteotomy is carried out as usual until 4.1x12 mm, followed by 4.5x10 mm and 5x8 mm.  Or with reamers, 2x12, 2.5 and 3x11, 3.5 and 4x8, 4.5x6.

The exposed buccal and lingual threads are to be covered by bone graft (red circles) and Osteotape with a hole in the middle.

From Bridge to Implants

Xin Wei, DDS, PhD, MS 1st edition 03/15/2015, last revision 03/15/2015