Mucogingival surgical procedures
Content
Periodontics
Mucogingival surgical procedures: A review of the iiterature
Jilireza Haeri, MS, DMD, MHSVFrancis G. Serio, DMD, M S "
This article provides an in-depth review of the iiterature on mucogingival surgical techniques. Indications and contraindications of various surgical procedures are discussed with reference to the literature. Surgical techniques and indications for increasing the zone of keratinized tissue, such as free autogenous grafts, applications of freeze-dried skin, and dermal matrix allografts, are described. Procedures to attain root coverage, such as various autogenous grafts and guided tissue regeneration techniques, aiong with appiication of chemicais such as citric acid to improve their success, are aiso described. (Quintessence Int 1999;30:475-483) Key words: allogratt, autogenous graft, guided tissue regeneration, keratinized tissue, mucogingivai surgery, root coverage
' iLjfucogingival surgery is defined, according fo tbe liVi Glossary of Periodontal Teims,^ as "a periodontal ^urgical procedure to correct defects in the morpholy, position, and/or the amount of gingiva." This term as been changed since it was first introduced by iedman^ in the 1950s as surgery designed to correct roblems such as pockets extending apical to the iicogingival junction, malpositioned frenum or muscle achment, and inadequate depth of the vestibule. Qoval of tbe frenum and deepening of the vestibule to correct these problems because the primary p, the lack of attached gingiva, was overlooked. . the 1960s, investigators sucb as Bjorn,' Nabers,* an^ developed mucogingival surgical teches such as free gingival grafts to increase tbe zone bratinized tissue. Miller,^ however, introduced the periodontal plastic surgery as "surgical proceused to correct or eliminate anatomic, developnfal, or traumatic deformities of the gingiva and oiar mucosa." This further expanded the objective ke surgery from creating an adequate zone of atêd gingiva to root coverage, along with correction problems such as root sensitivity, esthetic concerns. E l d fhe prevention of root caries. His intention in perOTming periodontal plastic surgery was to restore the 3sf tissue to the cementoenamel junction and ffeate a normal, healthy gingival sulcus.
INDICATIONS FOR INCREASING THE ZONE OF KERATINIZED TISSUE How much keratinized tissue is adequate?
As mentioned, for decades the goal of mucogingival surgical procedures was to gain keratinized tissue in areas with tnucogingival problems. The primary objective was to widen the zone of attacbed gingiva to improve periodontai healtb. In tbe past, many held such a philosophy without detemiining how much keratinized tissue, if any, was required to achieve health. In the 1970s, Lang and Loe' conducted studies to establish a relationship between tbe width of keratinized tissue and bcalth. They concluded that a rninimum of 2 mm of keratinized tissue is necessary to achieve health. Despite effective oral hygiene, areas wifh less than 2 mm of keratinized tissue exhibited persistent inflamtnation. However, observations by Dorfman et al* indicated that less than 1 mm of attached gingiva is adequate when inflammation is under control. They emphasized that therapy should be directed at controlling the bacterial plaque and reducing inflatnmation. An increase in the band of keratinized tissue is indicated in areas of persistent attachment loss. The work of other researchers''"'-^ confirmed this conclusion.
Importance of keratinized tissue in restorative and orthodontic treatment
'Assislant Proiessor. Department of Periodonlics, University of Mississippi, Sctiooi ot Dentistry, Jackson, Mississippi ! "Professor and Chairman, Department of Periodonlics, Uniuersity of Mississippi. School of Dentistry, Jackson, Mississippi. ^Reprint requests; Dr Aineza Haeri, Assistant Professor, Department ot " S i c s , University of Mississippi, Schooi of Dentistry, 3500 Nortfi State et, RcomD307, Jackson, Mississippi 39216-4505 Fax:601-984-6130.
The width of keratinized fissue for teeth involving subgingival restorative margins has been of concern to sotne investigators. Donaldson'^ emphasized the proper contouring of provisional crowns. Physiologic contour appears to cause less recession than poorly contoured crowns. He also noted that such crowns must have
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proper margins to avoid exertion of pressure on the surrounding tissue. Maynard and Wilson'-' stated that at least 3 mm of attached gingiva is required if restorative margins are to he placed in the gingival crevice. They also mentioned that the thicloiess of the keratinized tissue is adequate when a periodontal probe cannot he seen through the margin of the free gingiva. Other investigators'''* have confirmed that subgingival restorations with a narrow zone of keratinized tissue favor gingival recession and inflamtnation. Stetler and Bissada'" proposed a minimum of 2 mm of attached gingiva when margins are to be placed subgingivally. Orthodontic movement of teeth is another concern in areas with minimal attached gingiva. Batenhorst et al" observed formation of alveolar dehiscences on the facial surfaces of the mandibular incisors in monkeys as teeth were moved facially and occlusally. Resorption of the cementum and dentin was also observed with facial orthodontic movement. Steiner et al,'" in another study on monkeys, discovered significant recession of the gingival margin as teeth were orthodontically moved labially. Maynard and Wilson"' recommended that mucogingival surgery be performed prior to orthodontic treatment when there is a lack of keratinized tissue and there is demonstrable stress from the frenum on the margin. Other situations, such as eruption of the mandibular incisors labial to adjacent teeth, warrant mucogingival surgery. Maynard,^" in a retrospective study of patients with mucogingival probletns in need of orthodontic therapy, reemphasized the need for mucogingival surgery prior to orthodontic therapy to stabilize the attachment levels. Boyd" reviewed and discussed the indications and timing of mucogingival therapy with respect to orthodontic intervention. He suggested early correction of mucogingival problems, in the absence of malocclusion, to prevent further breakdown. However, if a malocclusion exists, consultation with the orthodontist is necessary to discover the nature and direction of movement. If there is a mucogingival problem labial to a tooth to be positioned lingually, then the orthodontic procedure would be undertaken first. The attached gingiva must be reevaluated after completion of the orthodontic treatment. Coatom et aF^ had a different opinion toward the need for mucogingival therapy on patients with orthodontic problems. Their results indicated that a minimal width of keratinized tissue (less than 2 mm) is capable of withstanding the stresses of orthodontic movements. Orthodontics should precede surgical intervention in areas with a prominent root or facially tipped teeth with at least a minimal width of keratinized tissue. In their study, 47% of the teeth had an increase in the zone of keratinized tissue following orthodontic therapy. However, in their opinion, a free
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gingival graft was necessary prior to orthodontic treatment in areas that eompletely lacked keratinized tissue. In general, it seems to be the consensus among investigators that a laci< of keratinized tissue warrants mucogingival surgery prior to orthodontic therapy.
SURGICAL PROCEDURES TO INCREASE KERATINIZED TISSUE
Free gingival graft Since the 1960s, the free gingival grafting technique has been the most predictable and popular method of increasing the band of keratinized tissue around teeth with mucogingival defects. Nabers,'' in 1966, oudined this technique; he suggested removal of the sulciilar epithelium, leaving the lamina propria intact. An incision at the mucogingival junction was made to expose the underlying connective tissue. The gingival tissue was excised from the palate and contoured and sutured in place to the periosteum. The connective tissue of the donor tissue contacted the connective tissue of the recipient area to maintain the blood supply to the graft. The area was covered with rubber dam material, and a surgical dressing was placed to cover the rubber dam,^ Others have contributed to advances in free gingival graft therapy. Pennel and coworkers" recommended the use of a periosteal fenestration to enhance graft stability. Dordick et aF'' evaluated placement of grafts directly on bone. After an initiai lag in healing when placed directly on bone, grafts placed on both periosteum and bone looked similar after 3 weeks. They also showed that nonpathologic dehiscences and fenestrations could be covered directly with donor tissue. Modern free gingival grafting technique has been reviewed by Cohen.^" Advantages of this treatment remain the high degree of predictabihty, the simplicity, and the possibilities for root coverage. Disadvantages include the necessity of a second operative site, the potentially compromised blood supply, greater discomfort, and possible hemostasis problems, especially at the donor site. Preparation is essentially the same as was outlined by Nabers,-' It is critical that the free gingival margin be removed to allow creeping attachment to occur. Figures la to lc illustrate the free gingival graft technique. Freeze-dried skin and acellular dermal matrix allograft Donor materials, such as freeze-dried skin, have heen used to eliminate the second surgical site. This material has been shown to be biologically compatible with the human oral tissue^^^^* and is nonimmunogenic.'"-"'
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Fig la The mandibular central incisor exhibits a mucogingival defecl.
Fig 1b The autogenous graft is sutured place over the recipient bed
Fig 1c The 4-weeii postoperative vievu reveals the keratinized tissue created as weil as partial roct coverage.
Fig 2a The mandibuiar canine and premoiars exhibit mucogingivai defects.
Fig 2b An Aiioderm ailcgraft is placed over the recipient bed.
Freeze-dried skin demonstrates no anti-HLA antibody activity following its placement in humans.^- This material has been proven to be as successful as free autogenous grafts in gaining keratinized tissue." Recently, an acellular dermal matrix allograft material (Alloderm, Lifecore Biomédical) was developed as an alternative to autogenous tissue for gingival grafts. This material has been utilized successfully in burn victitns since 1992 and for mucogingival surgeries since 1994 3 4 The ailograft is a biocompatible, aceliular connective tissue matrix taken from the dermal tissues of cadavers. The tissue is taken from the tissue bank and processed by a method that decellularizes the graft while leaving the basement membrane complex and collagen matrix intact. This method has the advantage of removing the immunogenic target cells while maintaining a structural framework to support fibroblast migration and new vascularization. Each material is furte tested to confirm the absence of the immunogenic cells and the presence of the intact matrixes before unOuiritessencelnternational
Fig 2c The v\ew 3 months after surgery reveals an adequate band of keratin i zat ion created with tinis material.
dergoing the viral inactivation step. Once this is accomplished, the tissue is freeze dried and packaged. The use of Allodertu resuited in an increase in the band of keratinized tissue with excellent color match."'** Alloderm appears to have more shrinkage, as compared with free-gingival graft. This factor is currently under investigation (Figs 2a to 2c).
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INDICATIONS FOR INCREASING ROOT COVERAGE
In addition to being used to increase tbe zone of attaebed gingiva, mucogingival surgical procedures are aiso used to gain root coverage, Probiems witb estbeties, root caries, and at times sensitivity of the exposed root surface often warrant sucb procedures. In tbeir early work, Sullivan and Atkins'' predicted possible root coverage using conventional free gingival grafts. They found that narrow recession defects have a greater cbance of complete repair than deep, wide defects, Avascularity of the exposed root surfaces is the primary factor for the lower success in areas with deep, wide defects, Miller^*^ redefined a recession and root coverage classification. His classification is based on tbe depth of tbe recession in relation to tbe mucogingival ¡unction and the amount of remaining interproximal bone. Greater root coverage is possible when tbe interproximal bone is in a more coronal position, Witb some minor technique modifications, even deep, wide defects can be predictably covered. Recession defects tbat extend apical to tbe mucogingivai junction in tbe presence of interproximal bone loss cannot be repaired completely.
SURGICAL PROCEDURES TO ATTAIN ROOT COVERAGE
extensive root abrasion or erosion exists. Tension on the flap after it is positioned should not be excessive. The pedicle height should not be excessive with respect to its width. Tbc graft needs a wide base to ensure proper perfusion of tbe coronal extent of the flap. Bone sbould never be left exposed over a root surface. Tbis will lead to bone loss and recession at the donor site. Coronally positioned flap Another procedure to gain root coverage is the coronally repositioned flap (Figs 3a to 3c). Restrepo''' made a full-tbiekness flap to tbe vestibular fornix along with 2 vertical releasing incisions. The flap was positioned coronally to cover the root surface. He found that problems such as a reduction of the vestibular depth following surgery are of short duration and that the depth will revert back to normal depth with muscie function, Allen and Miller"^ used a split-thickness flap instead of a full-tbiekness flap in their technique. Approximately 84% of tbe sites had complete root coverage, Tbe mean percentage in covering tbe denuded roots was 98%. A 2-step procedure was introduced to increase the zone of keratinized tissue prior to coronal positioning of thefiap,"'^First, a free gingival graft was placed apical to the denuded area to gain keratinized tissue. After 2 months of healing, coronal repositioning of the flap was performed for root coverage. Maynard-"' preferred tbe 2-step procedure over the lateral sliding flap because handling areas that involved thin adjacent gingiva during surgery made root coverage less predictable. He stated several criteria for success of the 2-step technique, including reduction of any root prominence, adequate release of the flap, healing time, interproximal bone crests to be at nonnal height, presence of sballow crevices interproximally, and tissue height to be witbin 1 mm of tbe cementoenamel junetion on adjacent tectb, MatteH^ evaluated the 2-step technique and discovered 65% root coverage on a predictable basis, Guinard and Caffesse'" compared the lateral sliding flap and coronally repositioned flap with a free gingival graft. They discovered no difference between the two regarding tbe gain in root coverage. A mean gain of 2.71 mm of root coverage was discovered 6 months pos topera tively following botb procedures, which was comparable to results obtained by Matter.'*^ A semilunar coronally positioned flap to cover the denuded root surface was introduced by Tarnow.^' This technique has an advantage over tbe other coronally positioned flap tecbnique because it requires no sutures. Approximately 2 to 3 mm of root coverage was obtained with this procedure.
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Lateral sliding flap The lateral positioned flap was first introduced in 1956 by Grupe and Warren.^^ They covered the exposed root suriace hy using a sliding flap operation. This was accomplished by removing the epithelial lining around the defect and making a full-tbickness flap around the adjacent tooth. After making a verticai ineision to free the pedicle, the flap was moved to cover the defect. A frenectomy was often combined with such procedure. Grupe-*" modified tbis tecbnique to retain the marginai gingiva of the donor site. The tnajor advantage of this procedure is the intact vaseularity of tbe donor tissue. One disadvantage of this procedure is the limited supply of keratinized tissue at the donor site. Bahat et aH' introdueed the transpositional flap technique to overcome the problem of lack of keratinized tissue of the donor site. Tbey made 2 vertical releasing incisions at tbe line angles of the adjacent teeth and then raised a fuli-thickness flap. They fheri slid the interdental papilla of the adjacent teetb to cover the defect. Cohen's atlas" outlines the lateral pedicie flap technique quite clearly. Several caveats must be remembered. The procedure is contraindieated in areas with deep interproximal poekets, severe interproximal bone loss, or excessive root prominence or where deep or
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Fig 3a The patient was concerned aboul ine appearance oí Ihe maxillary an ten OÍ teeth.
Fig 3b A full-thickness flap is raised and piaced cotonaliy to cover the exposed rool surfaces.
Free gingival graft to cover the root surface The free gingival graft has been utilized to cover the root surface in addition to increasing keratinized tissue. Hoibrook and Ochsenbein-*- evaluated root coverage with free autogenous grafts in 35 patients. They discovered 95.5°.o total root coverage in reeessions of less than 3 mm. Success for coverage was reduced to 80.6% and 76.6% in areas with recessions of 3 to 5 mm and greater than 5 mm, respectively. Total eoverage was achieved in 44''.'(i of the sites. Criteria for success were (1) elimination of the dead space under the graft hy proper suturing of the graft to the recipient bed and (2) harvesting of thin grafts (1.5 mm) for rapid revascularization and diffusion of fluids. Miller^* used citric acid treatment prior to placing the autogenous free gingival graft. Root coverage was achieved on a predictable hasis using this material. Approximateiy 89.90/0 of the graft sites had complete coverage. In a different study, he outhned factors associated with failure of free gingival grafts to ohtain root coverage.'" These factors were incomplete root planing, faiiure to apply citric aeid following root planing, improper preparation of the recipient site, and improper adaptation, size, and thickness. Tolmic et ñV reponed that 72.80/0 of their sites achieved complete root coverage. Creeping attachment Creeping attachment is the result of the coronal migration of the graft margin that occurs up to severai years following surgery" (Figs 4a to 4d}. Creeping attachinent 's more likely to occur in areas of narrow recession. Matter'^ obtained an average of 0.89 mm of creeping attachment approximately 1 year following surgery. Factors such as oral hygiene and tooth position are important in gaining attachment by creeping of the ginQuintessence internationai
Fig 3c SIX months ioliowing surgery, there is more than 60% root co^ierage on centrai and iateral inciso/s.
giva. Similar results were obtained by Bcil et al^" 1 year postoperatively. Harris^^ evaluated creeping attaehment following a connective tissue graft with partial-thickness double pedicle graft. Creeping attachment occurred in 95.5''.'ci of the subjects and was approximately 0.8 mm. Citric acid application Application of citric acid to improve the success of root coverage has been evaluated by many investigators. Register and Burdick,^^ in their histoiogic study on dogs, discovered that application of citrie acid (pH 1,0), applied for 2 minutes on the root surface, induced flap reattachment and cementogenesis. Garrett and coworkers" discovered that citric acid treattnent in conjunction with root planing exposed collagen fibrils. These fibrils were absent on surfaces that are not root planed. Citric acid also removes the radicular smear layer and opens the dentinal tubules to allow the formation of new cementum.'^ In addition, it demineralizes the root surface and removes residual endotoxins, thus rendering the environment favorable for attachment,'*
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Fig 4a Ttie mandibular cento! incisors require a iree gingival gratt.
Fig 4b A Iree gingivai grafl is placed to create a zone of keralinization.
Fig 4c One month following tfie surgery, a wide zone of keratinized tissue has been creaied
Fig 4d One year fo:iowing surgery, 3 mm ot creeping attachmerit has oocuired on the right central incisor.
According to iVIiller,^* citric acid application is one of the factors that increases the success of the root coverage utilizing free autogenous grafts. Liu and Solt"" discovered significant increase in the amount of keratinized tissue after use of citric acid with a 2-step free gingival graft followed by a coronally positioned flap. Tolmie et aP' obtained an overall mean root coverage of Sô.SO/b using citric acid. Evaluations by Ibbott et al*^' indicated no difference between the citric acid-treated and the untreated group. They found no clinical justification for tbe use of citric acid prior to free gingival grafting to cover the denuded roots. Approximately 50% to 60% mean root coverage was obtained in their study. This was confirmed by Bertrand and Dunlap,'^^ who stated that the success of the root coverage is dependent on the proper case selection rather tban citric acid application. They reported 70% coverage for both groups. In general, there seems to be controversy over tbe use of this material. Although several investigators have reported improvements using citric acid, comparative studies refute such findings.
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Double-papilla repositioned flap In some cases if the adjacent gingiva and the interdental papilla of the tooth with gingival recession are healthy, then it is possible to slide tfie papilla of ihe adjacent teeth from eitber side to cover the defect. This procedure is called the double-papilla repositioned flap. Cohen and Ross" stated the advantages of double-papilla repositioned flap technique over the lateral sliding flap: One benefit is tbe minimal arnount of exposure of the underlying periodontium at the donor sites. This reduces damage to the tissues, healing time, and postoperative complications. There is less tension of the donor tissue, and there is a greater amount of keratinized tissue at the interdental papillary area. They recommended this procedure for areas with no interproximai destruction.'" This is a predictable method to achieve root coverage, according to Harris.^'' However, he placed a connective tissue graft to cover the denuded root surface before suturing the papillae over tbe graft. Complete root coverage was attained in 80% of the cases, with overall mean root coverage of 97.4%.
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ng5a The mandibular right first premoiar estiibits a mucogingival delect with existing recession.
Fig 5b A subepithelial connective tissue gralt is placed on the root surface after making a spiit-thickness enveiope llap
Fig 5c Two months following surgery compiete root coverage is achieved
Subepithelial connective tissue graft Langer and Langer^^ described the subepithelial connective tissue graft for root coverage. Their criteria for placing such a gran were the existence of wide recessions or multiple root exposures along with inadequate donor sites for sliding flap surgery. A split-thickness nap with vertical incisions was created at the recipient site. The donor tissue was harvested from the palate to cover the denuded roots and sutured in place. A periodontal dressing was placed over the recipient area. They reported an increase in root coverage that ranged from 2 to 6 mm." The donor site healed with less discomfort than did the donor site in free gingival graft. The connective tissue graft was provided with a dual hlood supply from connective tissue on the nondcnuded portion of the root and the connective tissue side of the ñap.*^ Raetzke*^ placed the connective tissue graft under the flap, using the envelope technique to improve tissue support and nourishment. An overall mean root coverage of SO^o was obtained, along with an average gain of 3,5 mm in tissue keratinization. The procedure is illustrated in Figs 5a to 5c. Nelson^' developed a mucogingival graft procedure that consisted of a free connective tissue graft followed by sliding of the adjacent papillae. Tissue was harvested from the palate with a trapdoor approach, and a full-thickness flap with releasing incisions was reflected to allow repositioning of the papillae over the connective tissue. Nelson''' reported lOO^/o eoverage in areas with less than 3 mm of recession. Roots with 4 to 6 mm of recession had 92% coverage, and there was SS^/o coverage in the more advanced situations (7- to 10-mm recessions).
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As stated previously, Harris^" reflected a partialthickness flap, utilizing connective tissue with double papilla sliding to cover the graft. He achieved 100% root coverage in 80% of cases. Overall, 97.4% of the root surface was covered in this study. In a recent study, Harris" obtained a mean coverage of 94.8% by utihzing this technique. Guided tissue regeneration The principles of guided tissue regeneration have been applied to treat recession as well as to promote regeneration of periodontal osseous defects. Tinti et a F used expanded polyietrafluoroethylene (e-PTFE) {Gore-Tex, WL Gore) to treat facial recessions in humans. A íullthickness flap was reflected to approximately 3 mm apical to the bony crest. A partial-thickness flap was made from the base oi' the full-thickness flap in the apical direction. A semilunar incision was dissected to allow coronal movement of the flap without creating any tension. The root surface was heavily scaled and flaftened with a diamond bur. The membrane was trimmed and placed to cover the root surface. The flap was coronaiiy displaced to cover the membrane. Their results indicated root coverage that ranged from 28.6% to 75%, One problem with this technique is the difficulty in providing adequate space for regeneration and coverage of the membrane. In a different study, titanium-reinforced e-PTFE was used to create space for regeneration between the root surface and the membrane.^^ Use of this membrane resulted in a more predictable, faster, and simpler surgical procedure. The use of a trapezoidal flap and better suturing techniques could eliminate the problems associated with coronaiiy positioning the flap and maintaining an adequate blood supply.'"
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Bioresorbable membranes have also been utilized for root coverage of the denuded root surface. Roccuzzo ct aF' evaluated Guidor resorbablc tncmbrane (Guidor) and titanium-reinforced e-PTFE tnembrane for the treatrnent of human buccal gingival recession. Their results indicated no difference between the 2 rnembranes in the amount of root coverage achieved. Mean root coverage of 82.4o/o and 83.2% was obtained for the Guidor and c-PTFE rnembranes, respectively. Pini Prato et al'- compared a 2-stage free gingival graft followed by placement of a coronally positioned flap with e-PTFE. Their findings indicated no difference in the amount of root coverage in both groups. Root coverage of 72.7% and 70.Wo was obtained for the membrane and the control groups, respectively. However, the root coverage was more successful in areas of shallow recession when the coronally positioned flap (SLS^/o) was used than when guided tissue regeneration (63.5''.'o) was employed. In deeper recessions, guided tissue regeneration provided better root coverage (76.6»'o) than did the control (65.8%).
CONCLUSION
Various mucogingival surgical procedures were reviewed. The objectives, indications, and factors for the success of these procedures were described, and results obtained from different studies were discussed. The surgeon must be knowledgeable and up to date with the literature and reported findings so that he or she will be able to select the best surgical approach indicated for the patient to improve the results and achieve a more predictable outcome.
REFERENCES
1. Glossary of Periodontal Terms (ed 3). Chicago: American Academy of Periodontology 1992. 2. Friedman N. Mucogingival surgery. Tex Dent J I957;75: 358-362. 3. Bjorn H. Free transplantation of gingival propria. Sverige Tatidl Tidning 1963:22:684-689. 4. Nabers ]. Free gingival grafts. Periodontics 1966;4;243-245. 5. Cowan A. Sulcus deepening incorporating mucosal graft. JPeriodontol 1965;36:188-192. 6. Miller PD. Regenerative and reconstructive periodontai plastic surgery. Dent Clin North Am 1988;32 287-306. 7 Lang NP, Loe H. The relationship between the width of keratinized gingiva and gingivai health. J Periodontoi I972;43; 623-627. 8. Dorfmail HS, Ketinedy JE, Bird WC. Lotigitudinal evaiuation of free autogenous gingival autografts, J Cliti Periodontoi 1980:7:316-324. 9. De Trey E, Bernimoulin J. Influence of free gingival grafts on the health of the marginal gingiva. J Clin Periodontoi 1980;7:381-393.
10. Hangorsky U, Bissada N. Clinical assessment of free gingi-';' vai graft effectiveness on the maintenance of periodontalheaith. J Periüdontol 1980:51:274-278. 11. Salkin LM, Freedman AL. Stein MD, Bassiouny M. A longi- ' tudinal study of untreated mucogingival defects. J Peri-odontol 1987:58:164-166. ; 12. Freedman AL, Salkin LM, Stein MD, Green K. A 10 year longitudinal study of untreated mucogingival defects. J Periodontoi 1992;63:71-72. 13. Donaldson D. The etiologj' of gingival recession associated ' with temporary crowns. J Periodontoi 1974;45:468-471. '14. Maynard |G, Wiison RD. Physiologic dimensions of the pcriodontium significant to the restorative dentist. J Peri- ' odontol 1979:50:170-174 15. Ericsson I, Lindhe J. Recession in sites with inadequate width of the keratinized gingiva. J Chn Periodontoi 1984:11:95-103. 16. Stetler KJ, Bissada NF. Significance of the width of keratinized gingiva on the periodontal status of teeth with submarginai restorations. J Periodontoi 1987;58.696-70t). 17 Batenhorst KF, Bowers GM, Wiliiams JE. Tissue changes resulting from facial tipping and extrusion of incisors in monkeys. J Periodontoi 1974;45:660-668. 18. Steiner GG, Pearson JK, Ainamo J. Changes of the marginal periodontium as a result of labial tooth movement in monkeys. J Periodontoi 1981:52:314-320. 19. Maynard JG, Wilson RD. Diagnosis and management of mucogingivai probiems in children. Dent Child North Am 1980:24:683-703. 20. Maynard JG. The rationale for mucogingival therapy in the child and adolescent. Int J Periodont Rest Dent 1987:7(1): 37-51. 21. Boyd RL. Mueogingival considerations and their relationships to orthodontics. J Periodontoi 1978:49:67-76. 22. Coatom GW, Behrents RG, Bissada NF. The width of keratinized gingiva during orthodontic treatment: Its significant impact on periodontai status. J Periodontoi 1981;52; 307-313. 23. Pennel BM, Tabor JC. King KO, Towner JD. Fritz BD, Higgason JD. Free masticatory mucosa graft. J Periodontoi 1969:40:162-166. 24. Dordick B, Coslet JG, Seibert JS. Clinical evaluation of free autogenous grafts placed on alveolar bone. Part I. Clinicai predictability, J Periodontoi 1976;47:559-567 25. Cohen ES. Atlas of Cosmetic and Reconstructive Periodontal Surgery, ed 2. Baitimore, MD: Lea & Febiger, 1994:84-98. 26. Yukna RA, Sullivan WM. Evaluation of resultant tissue type following tbe intraoral transplantation of various lyophilized soft tissues. J Periodont Res 1978:13:177-184. 27. Carroii PB, Tow HD. Vernino AR. The use of allogenic freeze-dried skin grafts in the oral environment. Oral Surg 1974:37:163. 28. Mishkin DJ. Shelley LR Jr, Neville BW. Histologie study of a freeze-dried skin allograft in a human. A case report. JPeriodontol 1983:54:534-537. 29. Abbott WM. Sell KW. Alteration of histocompatibility and species antigens in skin by freeze-drying. Surg Forum 1972; 23:282. 30. Abbott WM, Hembree JS. Absence of antigenicity in freezedried skin ailografts. Cryobiology 1970:6:416. 31. Yukna RA, Turner DW. Robinson LJ. Variable antigenicity of lyophilized allogenic and lyophilized xenogenic sidn in guinea pigs. Int J Periodont Res 1977; 12:197-203,
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Í2, Gher ME Jr, Williams |É Jr, Vemino AR, Strong DM, Pelleu GB. Evaluation of the immunogenicity of freeze-dried skin allografts in humans. J Periodontoi 1980:51:571-577, 33. Yukna RA, Tow HD, Carrol PB, Vemino AR, Bright RW. Comparative clinieai evaluation of freeze-dried sidn aliografts and autogenous gingival grafts in humans. J Periodontoi 1977:4:191-199. U. Silverstein LH. Fundamentally changing soft tissue grafting. Dentistry Today 1997:40(3):56-59. 35. Silverstein LH. Calian D P An accllular dermal matrix allograft substitute for palatal donor tissue. Postgrad Dent 1996; 3:14-21. 36. Shulman J. Clinieai evaluation of an acellular dermal allograft for increasing t h e zone of attached gingiva. Pract Periodont Aesthet Dent 1996:8:205-208. 57. Suliivan HC, Atkins ]H Free autogenous gingival grafts. I. Principles of successful grafting. Periodontics 1968¡6121-129. 38. Miller PD. Root coverage using the free soft tissue autograft foLowing citric acid application. Part 111. A successful and predictable procedure in areas of deep-wide recession. Int | Periodont Rest Dent I985:5(2):15-37. 59. Grupo HE, Warren RE Repair of gingival defects by a sliding tlap operation. ] Periodontoi 1956:27:92-95. -lO. Grupe HE. Modified technique for the sliding flap operation. ) Periodontoi 1966:37:491-495. 41. Bahat BD, Handclsman M, Gordon |. The transpositional flap in mucogingival surgery. Int J Periodont Rest Dent 1990:10:473-482. 42. Restrepo OJ. Coronally repositioned flap: Report uf four eases. | Periodontoi 1973:44:564-567. 43. Allen EP, Miller PD. Coronal positioning of existing gingiva' Short term results in the treatment of shallow marginal tissue recession. ] Periodontoi 1989:60:316-319. 44. Bernimoulin | P , Luscher B, Muhlemann HR, Coronally repositioned flap. Clinical evaluation after one year. | Periodontoi 1975:45:1-13. 45. Maynard JG. Coronal positioning of a previously placed autogenous gingival graft. J Periodontoi 1977;48:151-155. 45. Matter ] Free gingival graft and coronally repositioned flap. J Clin Periodontoi 1979;6:437-442. 47. Guinard EA, Caffesse RG. Treatment of locaiized gingival recessions. Part HI. Comparison of results obtained with lateral sliding flap and coronally repositioned flaps. J Periodontoi 1978:49:457-461. 48. Tarnow DP. Semilunar coronally repositioned flap, J Clin Periodontoi 1986:13:182-185. 49. Hoibrook T, Ochsenbein C. Complete coverage of the denuded root surface with a one-stage gingival graft Int J Periodont Rest Dent 1983;3(3):9-27 50. Miller PD. Root coverage with t h e free gingival graft. Factors associated with incompiete coverage. ) Periodontoi 1987;58:674-681. 51. Tolmie PN, Rubins RP, Buck GS, Vagianos V, Lanz JC. The predictability of root coverage by way of free gingival autografts and citrie acid application: An evaluation by multiple clinicians. Int J Periodont Rest Denl 1991:11:261-271. 52. Matter j . Free gingivai grafts for the treatment of gingival recession. A review of some techniques. J Clin Periodontoi 1982:9:103-114.
53. Matter |, Creeping attachment of liee gingival grafts. A fiveyear follow up study. ) Periodontoi 1980:51:681-685. 54. Bell LA, Valluzzo TA, Garnick ||, Pennell BM. The presence of "creeping attachment" in human gingiva. J Periodontoi 1978:49:513-517 55. Harris RJ, Creeping attachment associated with the connective tissue with partial-thickness double pedicle graft, I Periodontoi 1997:68:890-899. 56. Register AA, Burdick FA, Accelerated reattachmcnt with cementogenesis to dentin, demineralized in situ. II. Defect repair, J Periodontoi 1976:47:497-505. 57. Garrett JS, Crigger M, Egelberg J. Effects of citric aeid on diseased root surfaces. ] Periodont Res 1978;13:155-163. 58. Miiler PD. Root coverage grafting for regeneration and aesthetics. Periodontoi 2000 1993:1:118-127. 59. Tanaka K, O'Leary TJ, Kafrawy AH. The effect of citric acid on retained plaque and eaietilus. ] Periodontoi 1989:60: 81-83. 60. Liu WJ, Solt CW, A surgical procedure for the treatment of localized gingival recession in coniunclion with root surface citric acid conditioning. J Periodontoi 1980:51:505-509. 61. Ibbott CG, Oles RD, Laverty WH. Effects of citric acid treatment on autogenous free graft coverage of localized reeession. ) Periodontoi 1985:56:662-665. 62. Bertrand PM. Dunlap RM. Coverage of deep wide gingival elefts with free gingivai autografts. Root pianing with and without citric acid demineralizalion. Int J Periodont Rest Dent 1988:8(l):65-77 63. Cohen DW. Ross SE. The double papillae repositioned flap in periodontal therapy. J Pedodontoi 1968:39:65-70. 64 Harris JR The connective tissue and partial thickness double pedicle graft: A predictable method of obtaining root coverage. I Periodontoi 1992:63:477-486. 65. Langer B, Langer L Subepithelial connective tissue graft technique for root coverage. ] Periodontoi 1985:56: 715-720, 66. Raetzi(e PB, Covering localized areas of root e.\posure employing the "enveiope"' technique. ] PeHodontoi 1985: 56:397-402. 67. Neison SW. The subpedicle connective tissue graft. A biiaminar reeonstructive procedure for the coverage of denuded root surfaces. ] Periodontoi 1987;58:95-102. 68. Tinti C, Vincenzi GP, Cortellini P, Pini Prato G, Clauser C. Guided tissue regeneration in the treatment of human facial recession, A 12-case report. J Periodontoi 1992;63:554-560. 69. Tinti C, Vincenzi GP. Expanded poiytetrafluorocthylene titanium-reinforced membranes for regeneration of mueogingival recession defects, A 12-case report. J Periodontoi 1994:65:1088-1094. 70. Tinti C, Vincenzi GP, Cocchetto R. Guided tissue regeneration in mucogingivai surgery. ] Periodontoi 1993:64: 1184-1191. 71. Roccuzzo M, Lungo M, Corrente G, Gandolfo S. Comparative study of a bioresorbable and a nonresorbable membrane in the treatment of human buccal reeessions. J Periodontoi 1996:67:7-14, 72. Pini Prato G, Tinti C, Vineenzi GP, Magnani C, Cortellini P, Clauser C. Guided tissue regeneration versus mucogingival surgery in the treatment of human buccal recession. J Periodontoi 1992;63:919-928.
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Mucogingival surgical procedures: A review of the iiterature
Jilireza Haeri, MS, DMD, MHSVFrancis G. Serio, DMD, M S "
This article provides an in-depth review of the iiterature on mucogingival surgical techniques. Indications and contraindications of various surgical procedures are discussed with reference to the literature. Surgical techniques and indications for increasing the zone of keratinized tissue, such as free autogenous grafts, applications of freeze-dried skin, and dermal matrix allografts, are described. Procedures to attain root coverage, such as various autogenous grafts and guided tissue regeneration techniques, aiong with appiication of chemicais such as citric acid to improve their success, are aiso described. (Quintessence Int 1999;30:475-483) Key words: allogratt, autogenous graft, guided tissue regeneration, keratinized tissue, mucogingivai surgery, root coverage
' iLjfucogingival surgery is defined, according fo tbe liVi Glossary of Periodontal Teims,^ as "a periodontal ^urgical procedure to correct defects in the morpholy, position, and/or the amount of gingiva." This term as been changed since it was first introduced by iedman^ in the 1950s as surgery designed to correct roblems such as pockets extending apical to the iicogingival junction, malpositioned frenum or muscle achment, and inadequate depth of the vestibule. Qoval of tbe frenum and deepening of the vestibule to correct these problems because the primary p, the lack of attached gingiva, was overlooked. . the 1960s, investigators sucb as Bjorn,' Nabers,* an^ developed mucogingival surgical teches such as free gingival grafts to increase tbe zone bratinized tissue. Miller,^ however, introduced the periodontal plastic surgery as "surgical proceused to correct or eliminate anatomic, developnfal, or traumatic deformities of the gingiva and oiar mucosa." This further expanded the objective ke surgery from creating an adequate zone of atêd gingiva to root coverage, along with correction problems such as root sensitivity, esthetic concerns. E l d fhe prevention of root caries. His intention in perOTming periodontal plastic surgery was to restore the 3sf tissue to the cementoenamel junction and ffeate a normal, healthy gingival sulcus.
INDICATIONS FOR INCREASING THE ZONE OF KERATINIZED TISSUE How much keratinized tissue is adequate?
As mentioned, for decades the goal of mucogingival surgical procedures was to gain keratinized tissue in areas with tnucogingival problems. The primary objective was to widen the zone of attacbed gingiva to improve periodontai healtb. In tbe past, many held such a philosophy without detemiining how much keratinized tissue, if any, was required to achieve health. In the 1970s, Lang and Loe' conducted studies to establish a relationship between tbe width of keratinized tissue and bcalth. They concluded that a rninimum of 2 mm of keratinized tissue is necessary to achieve health. Despite effective oral hygiene, areas wifh less than 2 mm of keratinized tissue exhibited persistent inflamtnation. However, observations by Dorfman et al* indicated that less than 1 mm of attached gingiva is adequate when inflammation is under control. They emphasized that therapy should be directed at controlling the bacterial plaque and reducing inflatnmation. An increase in the band of keratinized tissue is indicated in areas of persistent attachment loss. The work of other researchers''"'-^ confirmed this conclusion.
Importance of keratinized tissue in restorative and orthodontic treatment
'Assislant Proiessor. Department of Periodonlics, University of Mississippi, Sctiooi ot Dentistry, Jackson, Mississippi ! "Professor and Chairman, Department of Periodonlics, Uniuersity of Mississippi. School of Dentistry, Jackson, Mississippi. ^Reprint requests; Dr Aineza Haeri, Assistant Professor, Department ot " S i c s , University of Mississippi, Schooi of Dentistry, 3500 Nortfi State et, RcomD307, Jackson, Mississippi 39216-4505 Fax:601-984-6130.
The width of keratinized fissue for teeth involving subgingival restorative margins has been of concern to sotne investigators. Donaldson'^ emphasized the proper contouring of provisional crowns. Physiologic contour appears to cause less recession than poorly contoured crowns. He also noted that such crowns must have
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proper margins to avoid exertion of pressure on the surrounding tissue. Maynard and Wilson'-' stated that at least 3 mm of attached gingiva is required if restorative margins are to he placed in the gingival crevice. They also mentioned that the thicloiess of the keratinized tissue is adequate when a periodontal probe cannot he seen through the margin of the free gingiva. Other investigators'''* have confirmed that subgingival restorations with a narrow zone of keratinized tissue favor gingival recession and inflamtnation. Stetler and Bissada'" proposed a minimum of 2 mm of attached gingiva when margins are to be placed subgingivally. Orthodontic movement of teeth is another concern in areas with minimal attached gingiva. Batenhorst et al" observed formation of alveolar dehiscences on the facial surfaces of the mandibular incisors in monkeys as teeth were moved facially and occlusally. Resorption of the cementum and dentin was also observed with facial orthodontic movement. Steiner et al,'" in another study on monkeys, discovered significant recession of the gingival margin as teeth were orthodontically moved labially. Maynard and Wilson"' recommended that mucogingival surgery be performed prior to orthodontic treatment when there is a lack of keratinized tissue and there is demonstrable stress from the frenum on the margin. Other situations, such as eruption of the mandibular incisors labial to adjacent teeth, warrant mucogingival surgery. Maynard,^" in a retrospective study of patients with mucogingival probletns in need of orthodontic therapy, reemphasized the need for mucogingival surgery prior to orthodontic therapy to stabilize the attachment levels. Boyd" reviewed and discussed the indications and timing of mucogingival therapy with respect to orthodontic intervention. He suggested early correction of mucogingival problems, in the absence of malocclusion, to prevent further breakdown. However, if a malocclusion exists, consultation with the orthodontist is necessary to discover the nature and direction of movement. If there is a mucogingival problem labial to a tooth to be positioned lingually, then the orthodontic procedure would be undertaken first. The attached gingiva must be reevaluated after completion of the orthodontic treatment. Coatom et aF^ had a different opinion toward the need for mucogingival therapy on patients with orthodontic problems. Their results indicated that a minimal width of keratinized tissue (less than 2 mm) is capable of withstanding the stresses of orthodontic movements. Orthodontics should precede surgical intervention in areas with a prominent root or facially tipped teeth with at least a minimal width of keratinized tissue. In their study, 47% of the teeth had an increase in the zone of keratinized tissue following orthodontic therapy. However, in their opinion, a free
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gingival graft was necessary prior to orthodontic treatment in areas that eompletely lacked keratinized tissue. In general, it seems to be the consensus among investigators that a laci< of keratinized tissue warrants mucogingival surgery prior to orthodontic therapy.
SURGICAL PROCEDURES TO INCREASE KERATINIZED TISSUE
Free gingival graft Since the 1960s, the free gingival grafting technique has been the most predictable and popular method of increasing the band of keratinized tissue around teeth with mucogingival defects. Nabers,'' in 1966, oudined this technique; he suggested removal of the sulciilar epithelium, leaving the lamina propria intact. An incision at the mucogingival junction was made to expose the underlying connective tissue. The gingival tissue was excised from the palate and contoured and sutured in place to the periosteum. The connective tissue of the donor tissue contacted the connective tissue of the recipient area to maintain the blood supply to the graft. The area was covered with rubber dam material, and a surgical dressing was placed to cover the rubber dam,^ Others have contributed to advances in free gingival graft therapy. Pennel and coworkers" recommended the use of a periosteal fenestration to enhance graft stability. Dordick et aF'' evaluated placement of grafts directly on bone. After an initiai lag in healing when placed directly on bone, grafts placed on both periosteum and bone looked similar after 3 weeks. They also showed that nonpathologic dehiscences and fenestrations could be covered directly with donor tissue. Modern free gingival grafting technique has been reviewed by Cohen.^" Advantages of this treatment remain the high degree of predictabihty, the simplicity, and the possibilities for root coverage. Disadvantages include the necessity of a second operative site, the potentially compromised blood supply, greater discomfort, and possible hemostasis problems, especially at the donor site. Preparation is essentially the same as was outlined by Nabers,-' It is critical that the free gingival margin be removed to allow creeping attachment to occur. Figures la to lc illustrate the free gingival graft technique. Freeze-dried skin and acellular dermal matrix allograft Donor materials, such as freeze-dried skin, have heen used to eliminate the second surgical site. This material has been shown to be biologically compatible with the human oral tissue^^^^* and is nonimmunogenic.'"-"'
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Fig la The mandibular central incisor exhibits a mucogingival defecl.
Fig 1b The autogenous graft is sutured place over the recipient bed
Fig 1c The 4-weeii postoperative vievu reveals the keratinized tissue created as weil as partial roct coverage.
Fig 2a The mandibuiar canine and premoiars exhibit mucogingivai defects.
Fig 2b An Aiioderm ailcgraft is placed over the recipient bed.
Freeze-dried skin demonstrates no anti-HLA antibody activity following its placement in humans.^- This material has been proven to be as successful as free autogenous grafts in gaining keratinized tissue." Recently, an acellular dermal matrix allograft material (Alloderm, Lifecore Biomédical) was developed as an alternative to autogenous tissue for gingival grafts. This material has been utilized successfully in burn victitns since 1992 and for mucogingival surgeries since 1994 3 4 The ailograft is a biocompatible, aceliular connective tissue matrix taken from the dermal tissues of cadavers. The tissue is taken from the tissue bank and processed by a method that decellularizes the graft while leaving the basement membrane complex and collagen matrix intact. This method has the advantage of removing the immunogenic target cells while maintaining a structural framework to support fibroblast migration and new vascularization. Each material is furte tested to confirm the absence of the immunogenic cells and the presence of the intact matrixes before unOuiritessencelnternational
Fig 2c The v\ew 3 months after surgery reveals an adequate band of keratin i zat ion created with tinis material.
dergoing the viral inactivation step. Once this is accomplished, the tissue is freeze dried and packaged. The use of Allodertu resuited in an increase in the band of keratinized tissue with excellent color match."'** Alloderm appears to have more shrinkage, as compared with free-gingival graft. This factor is currently under investigation (Figs 2a to 2c).
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INDICATIONS FOR INCREASING ROOT COVERAGE
In addition to being used to increase tbe zone of attaebed gingiva, mucogingival surgical procedures are aiso used to gain root coverage, Probiems witb estbeties, root caries, and at times sensitivity of the exposed root surface often warrant sucb procedures. In tbeir early work, Sullivan and Atkins'' predicted possible root coverage using conventional free gingival grafts. They found that narrow recession defects have a greater cbance of complete repair than deep, wide defects, Avascularity of the exposed root surfaces is the primary factor for the lower success in areas with deep, wide defects, Miller^*^ redefined a recession and root coverage classification. His classification is based on tbe depth of tbe recession in relation to tbe mucogingival ¡unction and the amount of remaining interproximal bone. Greater root coverage is possible when tbe interproximal bone is in a more coronal position, Witb some minor technique modifications, even deep, wide defects can be predictably covered. Recession defects tbat extend apical to tbe mucogingivai junction in tbe presence of interproximal bone loss cannot be repaired completely.
SURGICAL PROCEDURES TO ATTAIN ROOT COVERAGE
extensive root abrasion or erosion exists. Tension on the flap after it is positioned should not be excessive. The pedicle height should not be excessive with respect to its width. Tbc graft needs a wide base to ensure proper perfusion of tbe coronal extent of the flap. Bone sbould never be left exposed over a root surface. Tbis will lead to bone loss and recession at the donor site. Coronally positioned flap Another procedure to gain root coverage is the coronally repositioned flap (Figs 3a to 3c). Restrepo''' made a full-tbiekness flap to tbe vestibular fornix along with 2 vertical releasing incisions. The flap was positioned coronally to cover the root surface. He found that problems such as a reduction of the vestibular depth following surgery are of short duration and that the depth will revert back to normal depth with muscie function, Allen and Miller"^ used a split-thickness flap instead of a full-tbiekness flap in their technique. Approximately 84% of tbe sites had complete root coverage, Tbe mean percentage in covering tbe denuded roots was 98%. A 2-step procedure was introduced to increase the zone of keratinized tissue prior to coronal positioning of thefiap,"'^First, a free gingival graft was placed apical to the denuded area to gain keratinized tissue. After 2 months of healing, coronal repositioning of the flap was performed for root coverage. Maynard-"' preferred tbe 2-step procedure over the lateral sliding flap because handling areas that involved thin adjacent gingiva during surgery made root coverage less predictable. He stated several criteria for success of the 2-step technique, including reduction of any root prominence, adequate release of the flap, healing time, interproximal bone crests to be at nonnal height, presence of sballow crevices interproximally, and tissue height to be witbin 1 mm of tbe cementoenamel junetion on adjacent tectb, MatteH^ evaluated the 2-step technique and discovered 65% root coverage on a predictable basis, Guinard and Caffesse'" compared the lateral sliding flap and coronally repositioned flap with a free gingival graft. They discovered no difference between the two regarding tbe gain in root coverage. A mean gain of 2.71 mm of root coverage was discovered 6 months pos topera tively following botb procedures, which was comparable to results obtained by Matter.'*^ A semilunar coronally positioned flap to cover the denuded root surface was introduced by Tarnow.^' This technique has an advantage over tbe other coronally positioned flap tecbnique because it requires no sutures. Approximately 2 to 3 mm of root coverage was obtained with this procedure.
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Lateral sliding flap The lateral positioned flap was first introduced in 1956 by Grupe and Warren.^^ They covered the exposed root suriace hy using a sliding flap operation. This was accomplished by removing the epithelial lining around the defect and making a full-tbickness flap around the adjacent tooth. After making a verticai ineision to free the pedicle, the flap was moved to cover the defect. A frenectomy was often combined with such procedure. Grupe-*" modified tbis tecbnique to retain the marginai gingiva of the donor site. The tnajor advantage of this procedure is the intact vaseularity of tbe donor tissue. One disadvantage of this procedure is the limited supply of keratinized tissue at the donor site. Bahat et aH' introdueed the transpositional flap technique to overcome the problem of lack of keratinized tissue of the donor site. Tbey made 2 vertical releasing incisions at tbe line angles of the adjacent teeth and then raised a fuli-thickness flap. They fheri slid the interdental papilla of the adjacent teetb to cover the defect. Cohen's atlas" outlines the lateral pedicie flap technique quite clearly. Several caveats must be remembered. The procedure is contraindieated in areas with deep interproximal poekets, severe interproximal bone loss, or excessive root prominence or where deep or
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Fig 3a The patient was concerned aboul ine appearance oí Ihe maxillary an ten OÍ teeth.
Fig 3b A full-thickness flap is raised and piaced cotonaliy to cover the exposed rool surfaces.
Free gingival graft to cover the root surface The free gingival graft has been utilized to cover the root surface in addition to increasing keratinized tissue. Hoibrook and Ochsenbein-*- evaluated root coverage with free autogenous grafts in 35 patients. They discovered 95.5°.o total root coverage in reeessions of less than 3 mm. Success for coverage was reduced to 80.6% and 76.6% in areas with recessions of 3 to 5 mm and greater than 5 mm, respectively. Total eoverage was achieved in 44''.'(i of the sites. Criteria for success were (1) elimination of the dead space under the graft hy proper suturing of the graft to the recipient bed and (2) harvesting of thin grafts (1.5 mm) for rapid revascularization and diffusion of fluids. Miller^* used citric acid treatment prior to placing the autogenous free gingival graft. Root coverage was achieved on a predictable hasis using this material. Approximateiy 89.90/0 of the graft sites had complete coverage. In a different study, he outhned factors associated with failure of free gingival grafts to ohtain root coverage.'" These factors were incomplete root planing, faiiure to apply citric aeid following root planing, improper preparation of the recipient site, and improper adaptation, size, and thickness. Tolmic et ñV reponed that 72.80/0 of their sites achieved complete root coverage. Creeping attachment Creeping attachment is the result of the coronal migration of the graft margin that occurs up to severai years following surgery" (Figs 4a to 4d}. Creeping attachinent 's more likely to occur in areas of narrow recession. Matter'^ obtained an average of 0.89 mm of creeping attachment approximately 1 year following surgery. Factors such as oral hygiene and tooth position are important in gaining attachment by creeping of the ginQuintessence internationai
Fig 3c SIX months ioliowing surgery, there is more than 60% root co^ierage on centrai and iateral inciso/s.
giva. Similar results were obtained by Bcil et al^" 1 year postoperatively. Harris^^ evaluated creeping attaehment following a connective tissue graft with partial-thickness double pedicle graft. Creeping attachment occurred in 95.5''.'ci of the subjects and was approximately 0.8 mm. Citric acid application Application of citric acid to improve the success of root coverage has been evaluated by many investigators. Register and Burdick,^^ in their histoiogic study on dogs, discovered that application of citrie acid (pH 1,0), applied for 2 minutes on the root surface, induced flap reattachment and cementogenesis. Garrett and coworkers" discovered that citric acid treattnent in conjunction with root planing exposed collagen fibrils. These fibrils were absent on surfaces that are not root planed. Citric acid also removes the radicular smear layer and opens the dentinal tubules to allow the formation of new cementum.'^ In addition, it demineralizes the root surface and removes residual endotoxins, thus rendering the environment favorable for attachment,'*
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Fig 4a Ttie mandibular cento! incisors require a iree gingival gratt.
Fig 4b A Iree gingivai grafl is placed to create a zone of keralinization.
Fig 4c One month following tfie surgery, a wide zone of keratinized tissue has been creaied
Fig 4d One year fo:iowing surgery, 3 mm ot creeping attachmerit has oocuired on the right central incisor.
According to iVIiller,^* citric acid application is one of the factors that increases the success of the root coverage utilizing free autogenous grafts. Liu and Solt"" discovered significant increase in the amount of keratinized tissue after use of citric acid with a 2-step free gingival graft followed by a coronally positioned flap. Tolmie et aP' obtained an overall mean root coverage of Sô.SO/b using citric acid. Evaluations by Ibbott et al*^' indicated no difference between the citric acid-treated and the untreated group. They found no clinical justification for tbe use of citric acid prior to free gingival grafting to cover the denuded roots. Approximately 50% to 60% mean root coverage was obtained in their study. This was confirmed by Bertrand and Dunlap,'^^ who stated that the success of the root coverage is dependent on the proper case selection rather tban citric acid application. They reported 70% coverage for both groups. In general, there seems to be controversy over tbe use of this material. Although several investigators have reported improvements using citric acid, comparative studies refute such findings.
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Double-papilla repositioned flap In some cases if the adjacent gingiva and the interdental papilla of the tooth with gingival recession are healthy, then it is possible to slide tfie papilla of ihe adjacent teeth from eitber side to cover the defect. This procedure is called the double-papilla repositioned flap. Cohen and Ross" stated the advantages of double-papilla repositioned flap technique over the lateral sliding flap: One benefit is tbe minimal arnount of exposure of the underlying periodontium at the donor sites. This reduces damage to the tissues, healing time, and postoperative complications. There is less tension of the donor tissue, and there is a greater amount of keratinized tissue at the interdental papillary area. They recommended this procedure for areas with no interproximai destruction.'" This is a predictable method to achieve root coverage, according to Harris.^'' However, he placed a connective tissue graft to cover the denuded root surface before suturing the papillae over tbe graft. Complete root coverage was attained in 80% of the cases, with overall mean root coverage of 97.4%.
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ng5a The mandibular right first premoiar estiibits a mucogingival delect with existing recession.
Fig 5b A subepithelial connective tissue gralt is placed on the root surface after making a spiit-thickness enveiope llap
Fig 5c Two months following surgery compiete root coverage is achieved
Subepithelial connective tissue graft Langer and Langer^^ described the subepithelial connective tissue graft for root coverage. Their criteria for placing such a gran were the existence of wide recessions or multiple root exposures along with inadequate donor sites for sliding flap surgery. A split-thickness nap with vertical incisions was created at the recipient site. The donor tissue was harvested from the palate to cover the denuded roots and sutured in place. A periodontal dressing was placed over the recipient area. They reported an increase in root coverage that ranged from 2 to 6 mm." The donor site healed with less discomfort than did the donor site in free gingival graft. The connective tissue graft was provided with a dual hlood supply from connective tissue on the nondcnuded portion of the root and the connective tissue side of the ñap.*^ Raetzke*^ placed the connective tissue graft under the flap, using the envelope technique to improve tissue support and nourishment. An overall mean root coverage of SO^o was obtained, along with an average gain of 3,5 mm in tissue keratinization. The procedure is illustrated in Figs 5a to 5c. Nelson^' developed a mucogingival graft procedure that consisted of a free connective tissue graft followed by sliding of the adjacent papillae. Tissue was harvested from the palate with a trapdoor approach, and a full-thickness flap with releasing incisions was reflected to allow repositioning of the papillae over the connective tissue. Nelson''' reported lOO^/o eoverage in areas with less than 3 mm of recession. Roots with 4 to 6 mm of recession had 92% coverage, and there was SS^/o coverage in the more advanced situations (7- to 10-mm recessions).
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As stated previously, Harris^" reflected a partialthickness flap, utilizing connective tissue with double papilla sliding to cover the graft. He achieved 100% root coverage in 80% of cases. Overall, 97.4% of the root surface was covered in this study. In a recent study, Harris" obtained a mean coverage of 94.8% by utihzing this technique. Guided tissue regeneration The principles of guided tissue regeneration have been applied to treat recession as well as to promote regeneration of periodontal osseous defects. Tinti et a F used expanded polyietrafluoroethylene (e-PTFE) {Gore-Tex, WL Gore) to treat facial recessions in humans. A íullthickness flap was reflected to approximately 3 mm apical to the bony crest. A partial-thickness flap was made from the base oi' the full-thickness flap in the apical direction. A semilunar incision was dissected to allow coronal movement of the flap without creating any tension. The root surface was heavily scaled and flaftened with a diamond bur. The membrane was trimmed and placed to cover the root surface. The flap was coronaiiy displaced to cover the membrane. Their results indicated root coverage that ranged from 28.6% to 75%, One problem with this technique is the difficulty in providing adequate space for regeneration and coverage of the membrane. In a different study, titanium-reinforced e-PTFE was used to create space for regeneration between the root surface and the membrane.^^ Use of this membrane resulted in a more predictable, faster, and simpler surgical procedure. The use of a trapezoidal flap and better suturing techniques could eliminate the problems associated with coronaiiy positioning the flap and maintaining an adequate blood supply.'"
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Bioresorbable membranes have also been utilized for root coverage of the denuded root surface. Roccuzzo ct aF' evaluated Guidor resorbablc tncmbrane (Guidor) and titanium-reinforced e-PTFE tnembrane for the treatrnent of human buccal gingival recession. Their results indicated no difference between the 2 rnembranes in the amount of root coverage achieved. Mean root coverage of 82.4o/o and 83.2% was obtained for the Guidor and c-PTFE rnembranes, respectively. Pini Prato et al'- compared a 2-stage free gingival graft followed by placement of a coronally positioned flap with e-PTFE. Their findings indicated no difference in the amount of root coverage in both groups. Root coverage of 72.7% and 70.Wo was obtained for the membrane and the control groups, respectively. However, the root coverage was more successful in areas of shallow recession when the coronally positioned flap (SLS^/o) was used than when guided tissue regeneration (63.5''.'o) was employed. In deeper recessions, guided tissue regeneration provided better root coverage (76.6»'o) than did the control (65.8%).
CONCLUSION
Various mucogingival surgical procedures were reviewed. The objectives, indications, and factors for the success of these procedures were described, and results obtained from different studies were discussed. The surgeon must be knowledgeable and up to date with the literature and reported findings so that he or she will be able to select the best surgical approach indicated for the patient to improve the results and achieve a more predictable outcome.
REFERENCES
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