The Larger an Immediate Implant, The Less Bone Graft

The lower right 1st molar of a 29-year-old lady is accompanied with buccal swelling (Fig.1 *) and has a large periapical radiolucency (Fig.2 *).  When the molar tooth is extracted, there is a single large socket without a septum (Fig.3). 

Osteotomy is established in the middle of the socket with a 2 mm pilot drill (Fig.4, ~4 mm in the new bone).  Since the latter is close to the mental loop (L), the osteotomy is later moved distally (<) using a Linderman bur. 

The osteotomy is enlarged with Bicon reamers 2.5 to 4 mm.  Then 5x20, 6x20 and 7x17 mm taps are used to create threads and test stability.  It is found that the last tap (Fig.5) among the three provides the best binding to the bone.  When the same size implant (7x17 mm) is placed (Fig.6 I), there is a fairly sized and circumferential gap which is filled with mixture of autogenous bone (from reamers), mineralized cancellous allograft and Osteogen (*).  If a larger implant were used (e.g., 8x17 mm), the amount of bone graft used would have been less.  It would also take less time for our body/bone to fill the gap.  Fig.7 is taken immediately postop.  The abutment (Fig.6,7 A with slots) is temporarily placed to hold perio dressing in place as securely as possible.  All the steps mentioned above help our wound heal as soon as possible.  It seems that there is no other way that can do better than immediate implant.  

The patient returns for follow up 1.5 months postop.  The perio dressing is still in place (Fig.8 D).  It appears that 3 of the slots on the abutment (Fig.9 *) contribute to retention of the dressing.  The roughness of the gingival margin (Fig.9 <) is due to incorporation of bone graft granules (Fig.10 <). 

Peri-implant space closes 6 months postop (Fig.11 *, as compared to Fig.7).  The gingiva including the interdental papillae (Fig.12 *) adapts nicely to the implant provisional before final crown cementation.  The only drawback is the thinness (>) of the occlusal surface of the provisional, which is fabricated 6 months postop.  There should be supraeruption of the opposing tooth.  An immediate provisional seems to be necessary.

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Xin Wei, DDS, PhD, MS 1st edition 07/28/2014, last revision 05/28/2018