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Inside Dentistry
November 2022
Volume 18, Issue 11
Peer-Reviewed

Layered Bone Grafting in Preparation for Dental Implants

Management of a maxillary defect with a calcium apatite material and particulate allograft

Timothy Kosinski, DDS

There are many biomaterials used in the bone grafting of socket sites following tooth extraction. If one considers all of the subcategories, there are hundreds of products on the market. Hydroxyapatite, tricalcium phosphate, and other calcium phosphate materials are promoted, and autografts and allografts represent other material options. The homogenous mixture of bioactive resorbable calcium apatite graft crystals and a bovine Achilles tendon collagen matrix (OsteoGen® Plug, Impladent Ltd.) that is used in this case report represents a significant advancement in synthetic grafting materials. This material utilizes a calcium deficient apatite similar to the mineral in human bone allograft. It is bioactive in that it controls soft-tissue invagination and forms a strong bond as it resorbs and is replaced by natural bone. In addition to containing the calcium apatite graft, the plug-shaped material also controls any connective tissue invagination through both a physical and chemical barrier. The physical barrier is created as the plug is firmly compressed into the defect, which causes epithelial cells to grow over the top rather than into the condensed material. As bleeding occurs, the hydrophilic matrix of intertwined graft crystals hydrate with blood and the resorption process begins with the release of calcium ions and the formation of bone.

Case Report

A patient presented with a failing bridge in the left-side maxillary posterior region. A preoperative radiograph revealed a severe vertical fracture of the bicuspid abutment which had resulted in bone loss. Following extraction and thorough surgical debridement of the extraction site and apical lesion, the site was evaluated. It was clear that the Schneiderian membrane was intact yet visible. To develop adequate bone for dental implant placement at the site, a large piece of the alloplastic calcium apatite graft material was carefully, yet firmly, packed into the defect, lifting the membrane. This material provided a new floor for the rest of the grafting procedure. The defect was then completely filled with a particulate allograft material (Newport Biologics™ Mineralized Cortico/Cancellous Allograft Blend, Glidewell Dental). This material was packed firmly into the defect but not crushed, extending to the facial contours of the adjacent teeth. Next, a resorbable collagen membrane (Newport Biologics™ Resorbable Collagen Membrane 3-4, Glidewell Dental) was passively positioned to serve as a barrier against epithelial ingrowth during the healing and remodeling phase. The membrane was trimmed to extend approximately 2 mm beyond the borders of the defect, and a sling Vicryl suture was used to reposition the envelope reflection.

Following a 4-month period of integration, the tissue appeared to be healing well, and a cone-beam computed tomography (CBCT) analysis demonstrated new bone formation. The site was again reflected, and two dental implants (Hahn™ Tapered Implant System, Glidewell Dental) were strategically placed. These implants will be allowed to integrate for an additional 4 months, after which implant level impressions will be made and individual screw-retained, implant-supported crowns will be fabricated and seated. In this manner, the edentulous space will be permanently restored, providing the patient with both improved function and esthetics.

About the Author

Timothy Kosinski, DDS
Diplomate
International Congress of Oral Implantologists
Master
Academy of General Dentistry
Affiliated Adjunct Clinical Professor
School of Dentistry
University of Detroit Mercy
Detroit, Michigan
Private Practice
Bingham Farms, Michigan

Timothy Kosinski, DDS

Preoperative digital periapical radiograph showing a conventional bridge with a severe vertical fracture of the bicuspid abutment resulting in bone loss. The negative symptoms experienced by the patient included swelling and discomfort.

Fig. 1

The tooth was removed in sections, and the tissue was reflected, exposing a large boney defect with significant granulation tissue that had to be curetted from the site.

Fig. 2

The Schneiderian membrane was exposed but not perforated. A piece of the alloplastic calcium apatite graft material was carefully condensed to the floor of the sinus with the intention of elevating it and protecting the sinus cavity from the placement of additional graft material.

Fig. 3

A particulate allograft material was then gingerly packed into the extensive defect, filling the entire site to the contour of the adjacent facial plates.

Fig. 4

To protect the allograft particulate from invagination of the epithelium during the integration process, a resorbable longterm collagen membrane was passively positioned at least 2 mm beyond the defect in all directions.

Fig. 5

The surgical site was sutured with resorbable Vicryl sutures, which were removed after 7 days. Note that there is an adequate band of attached gingiva available, which is a requirement for dental implant placement.

Fig. 6

A postoperative CBCT analysis was performed, and the sagittal view revealed that a controlled sinus elevation was accomplished along with correction of the facial defect.

Fig. 7

A digital periapical radiograph acquired 1-week postoperatively illustrates the opacity of the allograph material and the controlled placement of the graft. The ridge height was evaluated both radiographically and visually.

Fig. 8

A 4-month postoperative CBCT analysis indicated more mature bone turnover at the apical portion of the graft site. Measuring tools facilitated the determination of appropriate implant sizes for the individual areas.

Fig. 9

Prior to implant placement, another envelope reflection was performed with no vertical incisions into the mucosal tissue. This allowed for control of the reflection and repositioning and maintenance of a band of attached gingiva on the facial aspect of the ridge.

Fig. 10

A trephine was used to acquire a histologic sample before the first osteotomy was prepared. This sample was processed to evaluate the bone turnover. Here, the darker areas are natural bone formation, and the lighter areas are graft material that has not completely turned over during this short amount of time.

Fig. 11

An implant surgical protocol was followed to precisely position the first implant at the crest of the edentulous ridge and at least 2 mm from the adjacent root structure and along the central groove area of the adjacent dentition.

Fig. 12

After the second osteotomy was prepared, the implant was placed. The implants should be at least 3 mm apart because there is no blood supply available from the periodontal ligaments.

Fig. 13

The two implants were visually evaluated to confirm their positions.

Fig. 14

A postoperative radiograph was acquired and evaluated, and the tissue reflection was sutured closed. The implants will be allowed to integrate for an additional 4 months prior to uncovering and impression making for single-unit implant retained restorations.

Fig. 15

A postoperative CBCT analysis demonstrated proper positioning of the implants in the previously grafted surgical site.

Fig. 16

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