Mesial Slope of Upper 2nd Molar

There is a fistula distal to the tooth #2 with deep pocket distopalatally (Fig.1 *), corresponding to palatal root fracture (Fig.2).  There is a septum (Fig.3 S) between the buccal (B) and palatal (P) sockets.  Osteotomy is initiated in the center of the septum (Fig.4 black circle).  In fact the center of the socket is buccal (red circle), in which osteotomy should have been established because of the presence of the distopalatal bony defect associated with the root fracture and the distal fistula.  The less ideal initial osteotomy leads to palatal placement of the implant and abutment (Fig.11 vs. 12).

Fig.5 shows the mesial slope of the socket (M), which is more or less the center of the socket mesiodistally.  If the osteotomy were set up in the red circle (Fig.6) in the mesial slope (Fig.8 green dashed line), the trajectory of 4.5x11 mm dummy implant (Fig.7) would be more ideal (Fig.8 red outline) with more native bone contact.  Finally a longer IBS implant is placed (4.5x15 mm, Fig.9,10) to achieve primary stability (50 Ncm).  When the provisional is removed for impression 3 months 10 days postop, the implant is found to have been placed distopalatally (Fig.13), which should have been avoided.  It appears essential to use guide for a distal implant.  It is agonizing to re-encounter the off-axial implant (Fig.14) and the distopalatal access hole (Fig.15) 1 year post cementation.  It is also amazing that the abutment screw has not loosened.  A fair-sized piece of bone graft has just been removed buccally (Fig.15,16).  The patient complains of sensitivity 2 years 3 months post cementation, although there is no abnormality around the implant crown.  Guided surgery is essential to avoid restoration complication.  There is no thread exposure nearly 3 years post cementation; in fact the apical portion of the abutment is covered by the bone (Fig.17,18).

Upper Molar Immediate Implant, Prevent Molar Periimplantitis (Protocols, Table) Husband 导板与张口度 IBS/Guide Xin Wei, DDS, PhD, MS 1st edition 06/27/2017, last revision 05/24/2021