Sinus Lift Using Bone Expanders

When the primary 2nd molar is extracted, there is a buccal soft and hard tissue defect with thin layer of the keratinized gingiva (Fig.1 *).  Osteotomy is initiated as palatal as possible with 1.2 mm pilot drill, followed by 1.0/1.6 mm bone expander (Fig.2).  There is more than 40 Ncm when 1.7/3.1 mm bone expander is being used.  Drills are used for further osteotomy for a 4.0 mm implant.  Sinus lift is finished using autogenous bone and Osteogen as well as 2.4/3.7 mm bone expander 2 mm deeper than before (Fig.3).  A 4.5x11.5 mm UF implant cannot be placed at desired depth (Fig.4 (arrowheads: sinus lift)).  After osteotomy is increased with a drill for 4.5 mm implant, the implant is placed at more ideal level with insertion torque of 50 Ncm (Fig.5).  A 5.5x4(3) mm cemented abutment is placed.   Allograft and Osteogen is placed buccally.  An immediate provisional is fabricated to cover the graft.  In fact, the provisional stays in place without cement for 2 weeks (Fig.6 P).  The buccal wing is excessively long.  The provisional is removed (Fig.7) for revision and temporary cementation (Fig.8).  It appears that the buccal margin of the provisional should be further shortened so that the gingival margin (Fig.7 >) can grow more coronal to cover the abutment (A) margin.  When the patient returns 3.5 months postop, the buccal gingival margin is within normal limit.  The mesial abutment margin (Fig.9 *) is subgingival (white dashed line: gingival margin) and subcrestal.  The abutment is changed from 5.5x4(3) to 4.5x4(4) mm before impression, because of the distal margin being too close to the tooth #3.  The latter is in turn due to the fact that the implant is placed too distal with the trajectory off (Fig.10).  The position and trajectory should have been corrected as early as possible in osteotomy (Fig.13 red lines).  When the crown is delivered 5 months postop (Fig.11 C), there is no papillary recession (Fig.11 *), although the buccal plate is slightly atrophic (Fig.12 *).  There is no bone loss 5 years post cementation (Fig.14; the patient is 22 years old).  In fact the cortical bone forms between the implant threads and the neighboring root (Fig.15).

Upper Premolar Immediate Implant, Posterior Immediate Provisional, Next Xin Wei, DDS, PhD, MS 1st edition 12/21/2015, last revision 03/01/2021