Using an Acellular Dermal Matrix for Increasing Keratinized Tissue Around Dental Implants
•Background
•Another Method
•Surgical Procedure
•Postoperative Treatment
•Achieving Success
In previously published articles, investigators concluded that gingival recession may affect up to 90% of the population. Gingival recession ranges from one to three millimeters and is predominantly noted on the buccal surfaces of molar, premolar, and lower incisor teeth.
Although surgical grafting techniques have traditionally been used to restore these recession sites, an acellular allograft material has recently been developed for increasing the zone of keratinized tissue surrounding teeth and dental implants. The advantages of this material include improved color match, ease of use, predictability, reduced patient discomfort, and affordable treatment expense. This case study describes the use of an acellular dermal matrix (AlloDerm, LifeCell Corp.) to correct mucogingival complications while increasing or maintaining the keratinized attached gingival tissues.
Numerous investigations have examined the relationship between periodontal health and the width of the attached keratinized gingival tissue. Although Lang and Loe concluded that two millimeters of keratinized tissue and one millimeter of attached gingiva were sufficient to preserve periodontal health, the size of this zone was refuted by Kennedy, et al. These investigators concluded that gingival health could be maintained in the absence of keratinized tissue only if the patient maintained optimal home care, or if the keratinized gingiva was augmented by soft tissue grafting techniques.
It has also been determined that the width of keratinized tissue, whether around natural teeth or dental implants, doesn't influence periodontal health or gingival recession, regardless of plaque control. Many clinicians also advocate the importance of hygiene by the patient and keratinized tissue surrounding dental implants. This belief is based on the idea of peri-implantitis or poor soft tissue management as the causes for implant failure, rather than unsuccessful osseointegration.
In clinical situations where soft tissue adjacent to dental implants exhibits inflammation, recession, or abnormal color, the definition of success and survival becomes important. Implant survival refers to the duration of intraoral function, whereas success is defined as the quality of the implant (hard and soft tissue) during function within the oral cavity.
The focus on the diagnosis and treatment of gingival recession originates from the adverse clinical effects caused by this condition. These undesirable effects can manifest clinically as root sensitivity, root caries, decreased ability to maintain plaque control due to inflammation and pain when brushing, tooth abrasion, and gingival clefting.
In implant cases, the role of attached tissue surrounding the abutment may be of greater importance. Clinical evidence suggests that unattached alveolar tissue around dental implants is increasingly prone to chronic mechanical trauma from lack of daily home care or aberrant frenum attachment. When the peri-implant tissues are nonkeratinized, the connective issue then exhibits a lack of well-organized connective tissue fibers, and the peri-implant gingival complex is more susceptible to ingress of bacterial containment.
Therefore, it appears more logical to establish a region of attached keratinized gingiva around the dental implants to create a more functional soft tissue barrier. For example, if tissue inflammation develops (particularly within the peri-implant tissues) and results in gingival recession that exposes the threads of a screw-type implant or an implant surface roughened with a surface coating, then home care becomes compromised. This scenario would result in plaque build-up, gingivitis and other complications.
Various surgical techniques have been used to correct gingival recession by increasing the width of keratinized tissue. These procedures include rotated papillae autografts, double-split papillae, coronally repositioned flaps, lateral sliding pedicle flaps, and soft tissue autogenous grafts. Successful correction of these mucogingival defects generally refers to increasing the width of attached keratinized tissue. While masticatory mucosal soft tissue autografts have been traditionally used, autografting from the palate has its limitations due to the amount of tissue available, color discrepancies, pain of the donor site, and exostosis formation at the recipient site.
An acellular dermal matrix (AlloDerm, LifeCell Corp.) can correct mucogingival complications while increasing or maintaining the keratinized attached gingival tissues (Figures 1 through 4).
As soon as it is aseptically removed from the storage pouch, the acellular dermal matrix should be rehydrated in a tetracycline solution for at least 10 minutes and not more than four hours. The backing was subsequently removed and used as a template for the grafting site. Based on clinical experience, it is advantageous to wet the graft material with the patient's blood prior to the placement procedure. The connective tissue portion of the graft, which is subsequently placed on the recipient site, absorbs the blood. To prevent salivary and bacterial contamination, the surgical sites were isolated with sterile gauze.
The recipient site was prepared as if a free gingival graft procedure was being performed. A horizontal incision was placed coronally to the affected region and extended three to four millimeters mesial and distal of the area grafted. Mesial and distal vertical incisions were then performed apically at each end of the horizontal incision into the vestibule. A full mucoperiosteal flap was reflected eight to 10 mm apically and secured with 5-0 Chromic Gut sutures at the apical position. At the most apical area of the surgical site, the periosteum was scored with a sharp instrument to prevent the coronal migration of the nonattached tissue when healing occurrs. The area was then isolated from the oral environment by applying gauze moistened with the tetracycline solution to the area. The contoured graft material was carefully placed and sutured at the most coronal position, and pressure was applied to the site with tetracycline gauze for almost three to five minutes. To prevent blood from pooling between the recipient site and the acellular dermal material, the graft should lay flat on the site. The surgical site was then protected with periodontal dressing and left in place for 10 days.
The patient was instructed to apply ice packs to the treated site for four to six hours following the procedure. Oral hygiene instructions should include swabbing the area with a cotton ball dipped in an antimicrobial rinse and daily salt water rinses. Following dressing removal (10 days) and healing (two to three weeks), the patient resumed routine maintenance procedures. Clinical measurements were recorded at the time of graft placement and four to six weeks postoperatively using a periodontal probe.
This grafting procedure was performed to increase the amount of attached keratinized tissue where active gingival recession was noted on the facial surfaces of natural teeth. The patient reported some discomfort and experienced no postsurgical complications. The postoperative measurements recorded with the periodontal probe following removal of the dressing and sutures revealed 20% to 30% shrinkage of the graft material at four to six weeks postoperatively.
The results achieved with this procedure provided enhanced color match and increased the zone of attached tissue. Soft tissue augmentation around dental implants procedures can be performed without using the patient's own palate as a donor site. The material used exhibited numerous clinical advantages compared to traditional soft tissue gingival autogenous grafts. By correcting the soft tissue defect, clinicians are increasingly able to achieve long-lasting, predictable success for soft tissue adjacent to the clinical crowns of dental implants.
Dr. Silverstein is an associate clinical professor of periodontics at the Medical College of Georgia, Augusta. A lecturer on periodontics and implantology, he has authored numerous journal articles and textbook chapters. He maintains a private practice limited to periodontal care and implantology at Kennestone Periodontics in Atlanta.
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