Bone Trimmer Cannot Cut Crestal Bone at #19

According to design, a 5x7 mm implant is placed at #18 first, a vertical anchor pin (in fixture) is connected smoothly and osteotomy commences at #19.  Following tissue punch, bone trimmer cannot cut the crestal bone.  Pointed drill is used without flattening the pointed, hard crestal bone (both cortical and cancellous, Fig.1, as compared to Fig.2 (preop CT coronal section)).  It appears that the trajectory of these 2 implant is unaffected by no use of bone trimmer (Fig.3 (red dashed line: the superior border of the Inferior Alveolar Canal)).  There is no paresthesia postoperatively.  Retrospectively, should the crest be flattened by a surgical bur after tissue punch and removal of the guide?  Yes, said Jennifer.

Increase in speed to 800 RPM may help bone trimmer cutting.  Use longer trimmer (10.5 mm instead of 9 mm).  No bone trimmer does not affect osteotomy, but in the end use bone profiler to increase emergency profile for healing abutment (50 RPM).

The implants at #12 and 14 are placed 1 month later (Fig.4).  The 4 implants have impression (Fig.5,6) and cementation (Fig.7-9) at the same time.  Although the upper FPD is able to be removed after cementation in the mouth (Fig.7), the abutment screw cannot be tightened >20 Ncm (Fig.8).  The tooth #15 is tender early after crown/FPD cementation and needs occlusal adjustment twice.  The crown of #18 dislodges eight months post cementation (Fig.11 taken after recementation).  There is no bone loss at #13 and 15 (Fig.10), while the bone density increases around the implants at #18 and 19 eight months post cementation (Fig.11).  The abutment screw at #18 become loose 1.5 years post cementation; after proximal surface trimming twice (<), the abutment remains incompletely seated (Fig.12,13).  With suspicion of soft tissue block (Fig.13 *), a small abutment with longer cuff is completely seated (Fig.14).

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Xin Wei, DDS, PhD, MS 1st edition 08/27/2018, last revision 07/28/2020