Supplying the canvas to increase the esthetics of the painting
Even though ossseointegration of dental implants is well documented in the literature (1-6), success in implant dentistry continues to be the achievement of a stable, long-term, esthetic result including an intact mid-buccal soft tissue profile and interproximal papilla. Inadequate dimensions of soft tissue can result in esthetic and functional complications, including hygienic challenges, visual discrepancies, phonetic impediments, and susceptibility to future tissue recession (Fig. 1).
Fig. 1: Soft tissue recession around a dental implant restoration due to a deficiency in soft tissue volume.
There are a number of surgical and prosthetic techniques used to preserve existing peri-implant soft tissue prior to or during implant surgery. Examples include papilla sparring incisions (7), atraumatic tooth extraction, immediate implant placement with or without immediate provisionalization (8-12), and platform switching (13). These techniques are predicated on the fact that sufficient soft tissue exists in order to create an esthetic gingival-restorative complex.
A problem arises when there is a paucity of soft tissue to develop during an implant restoration. Although there is a controversy as to whether an “adequate” band of keratinized tissue is needed to achieve a long-term esthetic and functional restorative result (14-16), most authors would agree that having keratinized tissue around implant restorations can only be beneficial. Because the attachment apparatus is different between a tooth and a dental implant (17), in conjunction with a more limited blood supply to an implant compared with a tooth (18), implants are typically more susceptible to breakdown (19).
Keratinized tissue around implants can be one method of increasing resistance to bacterial infection. In fact, in a recent review by Greenstein and Cavallaro, the authors listed several indications that necessitated keratinized tissue presence around dental implants. These included patients with chronic inflammation despite hygiene efforts (Fig. 2), continued recession or attachment loss despite periodontal intervention, sites with soreness upon brushing, a predisposition toward periodontitis or recession, noncompliant patients, and those patients who want to improve esthetics (20).
Fig. 2: Persistent inflammation around a dental implant restoration with deficient keratinized tissue despite adequate oral hygiene.
Several surgical techniques have been described in the literature to increase the amount of keratinized tissue around teeth and dental implants. They include autogenous soft tissue grafts from the patient such as the free gingival graft or the subepithelial connective tissue graft, allogenic soft tissue grafts from human cadavers, xenogenic soft tissue grafts from animals, and newer cell-engineered grafts in culture dishes. Although autogenous tissue grafting is considered the gold standard in soft tissue augmentation procedures, much attention has been given to alternative procedures due to the morbidity associated with harvesting autografts.
Mucograft® is an example of a xenograft material that has been used in lieu of autogenous grafts to increase keratinized tissue around dental implants (21). Made of porcine collagen, this material has a compact outer layer that can be left exposed to the oral environment and a spongy inner layer that facilitates a blood clot and promotes angiogenesis. A major advantage in using this material for increasing keratinized tissue around dental implants is that it can be used in challenging areas with little to no attached soft tissue because primary closure over this graft material is not needed and it can be left exposed (Figs. 3a-3c).
Fig. 3a: Edentulous Nos. 12 and 13 slated for implant therapy with a limited amount of keratinized tissue.
Fig. 3b: Soft tissue Mucograft placed at the time of implant surgery in order to augment keratinized tissue height and thickness. Primary closure was not obtained over this graft.
Fig. 3c: Final restorations showing a large increase in the height of keratinized tissue, facilitating oral hygiene and increasing plaque resistance.
Editor’s note: Drs. Scott Froum and Chris Salierno will be presenting on implant complications on Aug. 4, 2012, in Las Vegas. For more information, click here.
Scott Froum, DDS, is a periodontist and co-editor of Surgical-Restorative Resource e-newsletter. He is a clinical associate professor at the New York University Dental School in the Department of Periodontology and Implantology. He is in private practice in New York City. You may contact him through his website at www.drscottfroum.com.
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