Implant Placement in a Narrow Ridge

Fig.1 shows the narrow ridge in the lower left posterior sextant after infiltration anesthesia.  After using a surgical stent and 2 mm pilot drills at the depth of 8 mm, three parallel pins are inserted at the sites of #18-20 for trajectory and depth check (Fig.2; red dashed line: the upper border of the Inferior Alveolar Canal). 

A 3x11 mm 1 piece implant is placed at the site of #20 with insertion torque > 60 Ncm (Fig.3).  When a 4.1x10 and 4.5x12 mm drills are being used at the sites of the #18 and 19, respectively, the buccal and lingual crestal bone starts to be perforated ~ 2 mm apicocoronally.

It is our instant decision to make osteotomy 2 mm deeper than the corresponding intended bone level implants so that the buccal and lingual perforation is less severe.  This is the result: 4.5x8 and 4.5x10 mm implants in place (Fig.4).  Later the last one is placed ~ 1 mm deeper.  After placement of 6.8x4 (2) mm abutments at #18 and 19 and adjustment of abutment height, a provisional bridge is fabricated.  One piece implants appear to be strong enough at sites of the lower canine and premolar.  Autogenous bone harvested during osteotomy is placed around the implant at #18 and 19 where the top micro threads are exposed.

The patient is doing well postop, but 1 month postop, she complains of pain in the left submandibular area.  When the immediate provisional is removed, the gingiva between the implants is erythematous (Fig.5 ^).  The provisional is modified with accentuated grooves between the margins of the implants (Fig.6 *) with oral hygiene instruction.  In fact the provisional is not cemented so that it is easy for self cleansing.  There is crestal bone resorption 3 months postop (Fig.7,8).  No further bone loss 1 year post cementation (Fig.9, cropped from pan).  The bone density around the implants increases 2 years 8 months post cementation (Fig.10).

Return to Lower Arch Reconstruction, Posterior Immediate Provisional #3 Intrusion

Xin Wei, DDS, PhD, MS 1st edition 06/04/2015, last revision 05/29/2018