Safe Margin is Achievable with Immediate Implant

According to an oral & maxillofacial neurosurgoen Dr. Shahrokh Bagheri, the safe margin for lower molar implant is 5 mm from the Inferior Alveolar Nerve (IAN).  In practice, it is quite difficult to achieve it.  But with immediate implant, it is achievable.

Infiltration with Xylocaine 68 mg, Septocaine 68 mg, Marcaine 9 mg and Epinephrine 60 mcg allows painless extraction and initial osteotomy with 1.5 and 2 mm pilot drills and 2.5-3.5 mm reamers at the depth of 14 mm.  The patient cannot tolerate the procedure when a 4 mm reamer is being used.  Based on preop CBCT studies, there should be about 3 mm from IAN.  Block anesthesia is administered with Xylocaine 34 mg, and Epinephrine 17 mcg.  Then osteotomy is finished without discomfort with placement of a 7x17 mm tap 14 mm from the gingival margin (Fig.1 T).  The diameter of the tap at the apex is 4.5 mm; there should be approximately 5 mm clearance from IAN (yellow dashed lines).  The stability of the tap is not ideal; the depth of the osteotomy is increased by 1 mm before placement of a 7x14 mm gingiva-level implant (Fig.2,3 I, insertion torque beyond 60 Ncm).  This large implant has engaged into the buccal and lingual plates, contributing to the primary stability.  A 6x3 mm abutment is placed (Fig.2,3 A) and an immediate provisional is fabricated.  After placement of bone graft (Fig.2,3 *) and collagen dressing (Fig.4 <), the provisional is temporarily cemented (P). 

The patient returns twice postop for implant/abutment reprep and provisional reline.  She returns 3.5 months postop, requesting final restoration; it appears that the graft has trabecular patterns (Fig.5 *).  The gingiva remains healthy 5.5 months postop, immediately prior to definitive crown cementation (Fig.6).

Return to Lower Molar Immediate Implant, Posterior Immediate Provisional

Xin Wei, DDS, PhD, MS 1st edition 12/31/2014, last revision 05/24/2015