July 24, 2020
by Gerald Rudick DDS, FAAID, FICOI, Ms. Arta Prenga
Various methods can be used to repair alveolar defects including autogenous, allogenic, xenogenic, and alloplastic graft materials, as well as guided bone regeneration.2 Among these, autogenous bone grafts are the gold standard for bone grafting.
For this patient, a very large volume of grafted bone was required to develop a n adequate implant site. As such, if the grafting bone was to be harvested intraorally, multiple donor sites would have been necessary. This approach would have created at least three concurrent surgical sites in the patient’s mouth.
The protocol described above used an alternate approach; the implant was placed in the ideal predetermined position, and the required bone was developed around and on top of the implant. No autogenous bone was needed, and additional intraoral surgical sites were avoided, reducing patient discomfort and potential complications.
This case was initiated in 2015 and completed a year later. It is still functioning asymptomatically and esthetically at this time, 4 years later.
A 40-year old male, heavy smoker, but otherwise in excellent health, presented with a mobile and sensitive upper right central incisor.
The preoperative radiograph revealed previous endodontic treatment, Post & Core and Crown restoration,and evidence of a root resection with retrograde sealing. Tooth mobility indicated a possible root fracture.
The right central was extracted under local anesthetic, but a significant portion of the root was retained in the bone.
A full thickness flap revealed the remaining portion of the root.
Upon removal of the root fragment, significant damage to the buccal bone plate was observed.
The soft tissues were approximated and sutured.
An acrylic denture tooth was selected and bonded to the adjacent teeth to act as a temporary esthetic replacement.
A five-week period was allowed for the site to heal, at which time a deep depression was noted in the gingival labial region.
Prior to re-entering the site, four vials of blood were drawn from the patient and stored without anticoagulant.
The vials were immediately centrifuged for 8 minutes at 1300 RPM and left undisturbed for 10 minutes. (Centrifuge, DDSGadget, Aventura FL)
The vials were opened drawing out the fibrin clot with some red blood cells attached.
The Platelet-Rich Fibrin (PRF) was withdrawn, and the attached red blood cells removed. PRF is dense fibrin biomaterial with bio-mechanical properties. A high-density fibrin clot can serve as a biological healing matrix by supporting cell migration and cytokine release
The PRF clots were pressed to obtain membranes and the fibronectin and vitronectin exudates were used to wet the grafting materials: Cerasorb M, ( Curasan, Wake Forest NC), Osteogen, Osteodemin (both Impladent Ltd., Jamaica NY) and a sprinkling of Metronidazole powder for its antibiotic properties. The remaining liquids were saved for wetting the surgical site and the implant at a later stage. The remaining fibrin membrane(s) were chopped and added to the graft mixture.
A full thickness flap with papilla sparing incisions was reflected to expose the edentulous ridge after the healing period at the time of the implant surgery.
A piezo scaler was used to denude the labial bone and to freshen the surface. It also caused some bleeding in the intended implant placement area. The recipient implant site was measured to select the implant. The implant was planned to have bone contact only on its mesial, distal, and apical thread areas. The coronal aspect of the implant was positioned to extend several mm above the ridge crest to allow a titanium mesh to be fastened to it, leaving space for the grafting mixture between the mesh and the implant surface.
An Adin implant (Adin Canada, Vaughan ON), Touareg-X 4.2D 16L, was selected because of its aggressive threads and additional length.
The implant was placed free-hand and secured at the apex, and slightly on the sides. The entire labial surface was completely exposed and without bone coverage. An abutment post was tried into the implant to assure proper positioning (implant repositioning is easiest at this stage).
titanium mesh1 was cut to size and secured with the cover screw of the implant.
The exposed implant surface was wetted with the retained PRF liquids.
The grafting material was placed over the implant surface and surrounding exposed bone and packed down.
The graft mixture was covered with two PRF pressed membranes.
The titanium membrane was folded over. (In this case, the mesh was cut from a stock sheet. Custom tenting mesh is available from Ace Surgical (Brockton MA) at an additional cost. The remaining PRF membrane was placed between the titanium mesh and the soft tissue prior to suturing to ensure better soft tissue healing.
A radiograph of the implant with the titanium mesh.
The soft tissue was repositioned and sutured with PTFE sutures (Osteogenics Biomedical, Lubbock TX). (On the mesial of #12, a remnant of the composite that was used to secure the temporary denture tooth is visible.)
The site was covered with COE-PAK periodontal dressing (GC Canada, Brampton ON), securing the unattached denture tooth. After 5 days, the periodontal pack was removed, and the denture tooth was bonded to the adjacent teeth.
At 10 days following the implant placement, some exposure of the titanium mesh was visible. Twice daily Peridex rinses were recommended. A slight exposure of the mesh is a common occurrence and did not cause any problems.
At ten weeks, a flap was opened, and the titanium mesh was peeled back and removed. Newly formed bone (patterned after the titanium mesh) was adhering to the labial surface of the implant.
The soft tissues have begun to heal. The provisional crown is in place. Some of the labial threads of the implant are exposed, and this will be treated by another grafting procedure.
Four months after the removal of the titanium mesh, the labial tissues were reflected with a wider incision opening, gently reflecting the papillae to expose the implant. Bone had been deposited on most of the labial surface of the implant, but additional coverage was required to improve esthetics.
The exposed surface of the implant was gently rinsed with Peridex. A small rotating titanium brush scrubbed the implant surface and threads. Holes were drilled in the adjacent bone to stimulate bleeding in preparation for a second grafting.
Gen-Os (OsteoBiol by Tecnoss, Pianezza, Italy) a porcine xenograft was placed on the exposed threads.
The site was then covered with an Evolution membrane (OsteoBiol by Tecnoss).
The flaps were sutured with Resorbable Glycolon sutures (Osteogenics Biomedical).
The soft tissue healed, and the abutment post was placed. The papillae on either side of the implant were well-developed, anatomically correct, and esthetic.
The exposed threads had been covered and the margins of the provisional crown were at the same level as the adjacent natural teeth.
Radiograph of the definitive crown and implant.
Facial view of the final cement-retained crown.
Lateral view of the final cement-retained crown. No dark metallic hue was visible at the margin of the crown.
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About the Author
Dr. Gerald Rudick, a graduate of McGill University, completed a post-graduate program in Oral Rehabilitation at the Hebrew University of Jerusalem, Israel. He is an Associate Fellow-American Academy of Implant Dentistry; Diplomate, Fellow and Master-Implant Prosthodontic Section-International Congress of Oral Implantology and was selected a Top Contributor for OsseoNews in 2018. He can be reached at 514 342 4444, or by email: email@example.com.
Ms. Arta Prenga is a graduate of The Dental Assisting Program at CDI College, Montreal, is a surgical dental assistant and has worked with Dr. Rudick for seven years.
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