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Dental Tribune U.S. Edition

Dental Tribune U.S. Edition | November 2013 A3CLINICAL Cosmetic periodontal surgery (Part 4A): By David L. Hoexter, DMD, FACD, FICD, Editor in Chief P art 4A of this series on cosmetic periodontal surgery deals with various barriers that have histor- ically been used to aid periodon- tal regeneration. This article is limited to the use of barriers to achieve predictable regenerative coverage of unesthetic root recession using the guided tissue regen- eration (GTR) technique with resorbable barriers. It also includes a case study on the use of a polylactic acid membrane to regenerate gingival root coverage where root recession is clinically noted. Periodontal disease leads to destruc- tion that causes a void in which unde- sired cells have diminished the sup- portive periodontia. Proper periodontal surgery to correct this hinges on proper regeneration of the lost tissue. Restoration of the lost periodontia in- volves regenerating the lost supporting structures, including alveolar bone, con- nective tissue, keratinized epithelium, periodontal ligament and cementum. By placing a barrier to inhibit the undesired cells — and enabling the desired progeni- tor cells to procreate — we can selectively guide the desired restoration of the lost periodontia. For the past 50 years or so, regeneration of the periodontia, including both osse- ous and soft tissue, has been achieved successfully by the use of barriers. The most popular barrier to date is a mem- brane, although there have been several other barriers used as the technique has developed. A barrier should create and maintain a sufficient space where an adequate blood supply can form to enable regeneration to occur. The space must be preserved for a certain period of time, and the barrier should be immobile for that same time period. The barrier needs to preserve this space while preventing epithelial cells and connective tissue cells from migrat- ing into it. But the barrier also must be porous, so that metabolites can penetrate through it to keep the underlying devel- oping regrowth alive. With the GTR technique, popularized by Dr. Nieman, we can inhibit the causal factors of the periodontal disease, thus preventing reoccurrence and enabling proper cellular regeneration. This technique involves forming a po- rous barrier membrane that excludes the undesired cells, yet allows nutriment through its porous membrane to aid the selective population by undifferentiated mesenchymal — advancing the regen- erative goal. Historically, different materials were developed to act as barriers for use in the GTR technique. Initially, nonresorb- able membranes were used. A Teflon bar- rier expanded polytetrafluoroethylene (ePTFE) membrane that was porous was Fig. 1: Recession of the upper left cuspid #11 is of primary concern to the patient. Also present is the recession of the #12, which is of no esthetic concern to the patient. After discussion about treatment options, the patient opts not to use a membrane barrier in the treatment of the #12. Photos/Provided by Dr. David L. Hoexter Fig. 2: The incised surgical area is seen following administration of local anesthetic and initiation of the procedure. Prior to surgery, no sensitiv- ity to temperature change is confirmed in tooth #11 and #12. Also determined is that aggressive oral hygiene, especially with brushing, is a primary contributing factor to the recession. popularized by Gore. This ePTFE, like its more economical equal, Sartorius, as well as other nonresorbable barriers, such as Millipore filters, worked well. However, because they are nonresorbable, they re- quired a second surgical procedure after the healing process was complete, usu- ally months later, to remove the nonre- sorbable membranes. This second pro- cedure required another round of local anesthetic and another uncomfortable healing period. Other Teflon membranes, which were nonporous and nonresorbable, also were available, but they were not recommend- ed for GTR because their lack of poros- ity inhibited essential nutrition from passing through, thus blocking newly forming blood supply from regenerat- ing. These Teflon membranes have, in fact, the same regenerative properties as a rubber dam and should not be used or contemplated for GTR. The limitations of these early barriers prompted companies to develop resorb- able barrier membranes that eliminated the necessity of a second surgical proce- dure, much to the appreciation of patient and practitioner alike. These membranes have all the desired qualities of the non- resorbable group but do not need a sec- ond surgical procedure to be removed. Different materials lead to different rates of absorption time, resulting in different times of inhibition of epithelium and/or connective tissue invagination. Different materials may result in different consis- tency of results. The resorbable membrane barriers used most frequently in cosmetic root recession coverage are divided into three main groups, based on the materials: 1) polyglactin acid, 2) polylactic acid, and 3) collagen. The polyglactin and polylactic mem- branes are similar except that polylactic acid membranes contain a citric acid es- ter that enables them to be malleable. Resorbable polylactic barrier mem- branes were the first popular resorb- able membranes approved by the FDA. Produced under the commercial name of Guidor, the product was developed for GTR procedures, and its malleabil- ity made clinical handling easier. The resorbsion of this material is through hydrolysis. Results show no soft-tissue reactions during healing, and yet, there are reduced probing depths during heal- ing, and a definite gain of clinical attach- ments. This article is limited to the use of GTR specifically in recession-coverage regeneration. Membrane barriers of polyglactin acid were still used after Guidor received ap- proval from the FDA. However, one of the principles of a regenerative membrane is its period of longevity. It is accepted that the barrier should be stable and present in the desired position for at least six to eight weeks. The polyglactin barriers of the era resorbed inconsistently. Reports of resorbsion varied in ranges of time. The barriers were not present long enough to consistently meet the time required for success. Therefore, this article limits its focus to the use of polylactic membrane, which consistently meets the required time period for retention. Case presentation The patient, a 31-year-old male, presented at my office with gingival recession. His chief complaint was his gingival reces- sion in his upper left cuspid (#11). There wasnosensitivitytotemperaturechange. He was aggressive in his oral hygiene, es- pecially with his brushing. Noted was the abrasion of the #11 at the recessed root exposed area. He was concerned with the appearance of looking older than he was and with the probability of living with the longer-appearing tooth (#11). The upper left first bicuspid (#12) also had recession and root exposure, al- though it was not noticeable to the pa- tient. Both the #11 and #12 were asymp- tomatic, but only the more noticeable #11 bothered the patient visually (Fig. 1). Local anesthetic was administered. Then, using a #15 blade, the sulcular inci- sion was performed from the gingiva to the osseous crest (Fig. 3). This is done to preserve the keratinized gingiva neces- sary for our final goal. Buccalflapreflection,usingtheHoexter ” See BARRIERS, page A4 Fig. 1 Fig. 2 Barriers of success