Socket Preservation vs. Immediate Implant

A 84-year-old man has broken the lower right 2nd bicuspid (Fig.1: #29).  It is scheduled to be extracted and have an immediate implant.  When the residual root is removed, the apical distal wall is too painful to be debrided.  Intraop PA shows a perforation (Fig.2 between arrowheads) between the bicuspid and the 1st molar.  There is large radiolucency around the mesial root of the molar.  A closer look demonstrates a fistula buccal to the molar (Fig.1 <).  It appears that the molar is nonsalvageable and should be replaced by an immediate implant.  Due to schedule conflict, it is decided to do socket preservation first.  Fig.3 reveals that the tooth #30 is extracted.  Both of the sockets have been thoroughly debrided and ready for bone graft (allograft and Osteogen).  The coronal portion of the bone between these teeth has undergone green stick fracture during molar extraction. Note that the buccolingual (B-L) width of these two teeth is almost identical.

Three months later, the B-L width at the site of #29 is significantly reduced (Fig.4).  Upon X-ray exam, there is decreased bone density between these two sockets (Fig.5 *).  Socket preservation seems not to live its expectation.  The obvious advantage is formation of callus-like bone in the molar socket (Fig.6 *, between the buccal (B) and lingual (L) plates).  The significant decrease in the buccolingual width at the site of #29 is associated with buccal plate crack during implantation (Fig.7 *).  At the site of #30, the lingual plate is so low that there is implant thread exposure (Fig.8 <).  Mixture of autogenous bone (harvested from drilling with Bicon reamers) and synthetic bone (Osteogen) is placed mainly buccal to the implant #29 and lingual to #30 (Fig.9), followed by collagen membrane.  Bone density between these two implant increases due to the bone grafting (Fig.10 *, as compared to Fig.5).  In fact, the implant at the site of #29 is found loose 1 month postop.

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Xin Wei, DDS, PhD, MS 1st edition 07/30/2014, last revision 01/19/2018