SOCKET GRAFT MANAGEMENT: WHAT YOU NEED TO KNOW By: David H. Wong, DDS | Diplomate, American Board of Periodontology Think for a moment about how common tooth extractions are in dentistry. Now think about bone loss, how it’s virtually irreversible, and how it’s associated with disease and inflammation. How are these two related and what can be done about it?
• Provide quality bone for implant osseointegration
As we explore this question, we need to ask more questions: What happens to the bone after a tooth is extracted? How long does it last? Is it preventable? How?
SURGICAL CONSIDERATIONS TO SOCKET SITE MANAGEMENT When it comes to extracting a tooth, care must always be taken to preserve the facial and lingual cortical plates. Without these valuable structures, a simple socket graft may turn into a more complex procedure. For the purposes of this article, socket graft management will be discussed assuming a four-walled socket. Situations where a bony wall is missing (advanced periodontal disease, root fractures, endodontic lesions, etc.) often require additional planning and different execution. To simplify socket grafting procedures, every effort should be made to minimize trauma. Utilizing an “atraumatic” surgical technique is of utmost importance.
INTRODUCTION There are many reasons why teeth are extracted: severe periodontal disease, non-restorable caries, root fractures, orthodontics, pathology, etc. What the literature says about extractions and bone loss may be surprising. For example, tooth loss creates 40% to 60% alveolar bone loss in the first 2-3 years and then a resorption rate of 0.5% to 1% every year for the rest of the patient’s life.3 Bone loss also occurs both horizontally and vertically. While the extraction socket does fill with bone, the socket is also often occupied with connective tissue.2 What is the cause of the quantity and rapidity of bone loss? The reason is best explained by the bundle bone, which occupies the facial plate of a tooth. This bundle bone is very avascular and receives its blood supply from the periodontal ligament, the periosteum, and the alveolar marrow spaces.1 Once a tooth is removed, the loss of bundle bone is rapid and is responsible for the majority of the bone loss that occurs early on. This bone loss occurs nearly universally in all individuals as well as with all teeth to varying degrees. The most common treatment to minimize (not eliminate) bone loss is to place a bone replacement graft into the socket at the time of extraction. There are several notable benefits to grafting an extraction socket:5 • Enable the placement and stability of implants • Reduce the loss of bone volume • Reduce the need for additional bone grafting
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• Improve the esthetics of the final prosthesis • Regenerate bone faster • Protect the adjacent teeth
GRAFT MATERIAL SELECTION When it comes to choosing bone replacement graft materials, the options are endless. Fortunately, for basic socket grafting needs several materials will suffice. Bone graft materials are generally categorized into four groups: autografts, allografts, xenografts, and alloplasts. • Autograft - Donor and recipient sites are in the same individual. • Allograft - Donor and recipient sites are from two different individuals of the same species, i.e. cadaver bone. These graft materials may also be further subcategorized into mineralized or demineralized products. • Xenograft - Donor and recipient sites are from two different individuals of different species, i.e. animal bone. • Alloplast - A group of synthetic bone grafts such as ceramics and glasses and a multitude of other materials.
It is important to note several features about grafted bone compared to “native” bone. Grafted bone yields similar bone-to-implant contact as with native bone (40%-65%) and offers good primary stability at the time of implant insertion. It also does not impair early osseointegration. Grafted bone is able to sustain loading conditions long-term. THE SCIENCE OF BONE GRAFTING There are several mechanisms at work when it comes to how bone graft materials are able to aid in the regeneration of bone in an extraction socket. Osteogenic materials are able to directly form bone. This is an ideal property. Meanwhile, osteoinductive graft materials stimulate bone growth by influencing undifferentiated mesenchymal cells. Finally, osteoconductive bone grafts lead to bone formation by serving as a scaffold for bone growth. Despite the properties that bone graft materials possess, several other factors must be present to allow for proper and predictable bone growth. According to Wang and Boyapati6 four critical factors must be present: • Primary closure/Passivity of the flap • Angiogenesis • Space Maintenance of the graft • Stability of the graft When performing bone grafting procedures, all of these factors should be considered to allow for maximum predictability and success. CASE STUDY A 65-year-old healthy female presented with a hopeless lateral incisor (#7). The tooth had fractured at the gingival margin and was determined to be non-restorable (Fig. 1). She presented with the crown of the tooth bonded to the adjacent teeth. Her ultimate goal was to have the tooth replaced with a dental implant. This case series focuses on site preparation with extraction of the tooth and placement of a socket graft.
