Uneven Buccolingual Bone

Initial osteotomy at #29-30 shows that there is clearance at #31, but not at #30 (Fig.1 (red dashed line: the superior border of the Inferior Alveolar Canal)) and that the osteotomy at #29 is close to the root of #28 (Fig.2).  Moving the osteotomy of #29 distally using Lindamann bur is not sufficient (Fig.4 when a 3.8x10 mm drill is in place).  A de novo osteotomy is established distally (Fig.5,6 (red dashed line: old osteotomy)). 

At #31, the implant has to be placed low because of low buccal bone (Fig.8 B (vs. much higher lingual (L) one) in spite of 2 mm implant being coronal to the distal bone (Fig.3 ^).  The margin of the abutment with 6 mm cuff appears apical to the distal crest (Fig.3 *).  Bone graft is placed around the exposed implant threads (Fig.6 *) after placement of Osteogen plug between the implants (P).  After placing PRF membrane (Fig.7 M) and plug (P) over the bone graft, Cytoplast (Fig.6,8 C: non-resorbable membrane) is used to assist wound closure.  Finally periodontal dressing is applied for further wound protection (Fig.9).

The patient is doing fine postop.  He returns asymptomatic 5 weeks postop.  There is minimal gingival erythema lingual to the non-resorbable membrane (Fig.10 C).  After removal of plaque around the abutments, the membrane is removed (Fig.11).  Two weeks later, the wound has healed (Fig.12).  The abutment at #29 is basically buried, while the one at #31 is covered by the lingual gingiva. 

The patient will return in two weeks (total 2 months postop).  The abutment at #29 will be changed to a longer one (3.9x7(6) mm).  Provisional FPD will be fabricated with an emphasis to push the surrounding (especially lingual) gingiva away from the abutments, most likely using gauze as gingival retraction cord.  The crown at #2 will be trimmed to have clearance.  Fig.13 is taken 3 months post cementation.  CBCT taken 1 year 9 months post cementation shows the uneven buccal (B) and lingual crests (Fig.14,15 arrowheads).

Return to Lower Molar Immediate Implant, Prevent Molar Periimplantitis (Protocols, Table), IBS, #19, 13,14 GEM21S

Xin Wei, DDS, PhD, MS 1st edition 03/30/2017, last revision 04/09/2020