Types of Studies Reviewed. The authors reviewed controlled clinical trials to assess the outcome of gingival grafting. They also included histological studies in this article to elucidate the type of healing after those procedures were performed.

Results. The studies showed that the combination of CTG and coronally positioned flaps yielded a higher percentage of root coverage compared with other techniques. When GTR using bioabsorbable or nonbioabsorbable membranes was compared with CTG, the studies were inconclusive. Some studies found that GTR was as effective as CTG, while the others found that CTG was superior.

Clinical Implications. Gingival grafting to treat recession is a predictable and reliable periodontal procedure.

	SOFT-TISSUE GRAFTING

TOP ABSTRACT SOFT-TISSUE GRAFTING GUIDED TISSUE REGENERATION CONCLUSION REFERENCES

 
One goal of soft-tissue grafting is root coverage. Many techniques and flap designs have been used to meet that goal; some do not require a donor site (pedicle grafts), while others do (free autogenous grafts). It often is difficult to anticipate the success rate of root coverage procedures (table), since coverage depends on several factors, including the classification and location of the recession and the technique used. The gingival dimension most commonly assessed is the height—the distance between the soft-tissue margin and the mucogingival line measured in millimeters. An increase in gingival height, independent of the number of millimeters, is considered to be a successful outcome of gingival augmentation procedures.¹

Wood and colleagues⁴ used re-entry procedures to compare crestal radicular bone responses with full- and partial-thickness flaps. They concluded that, regardless of the flap procedure used, loss of crestal bone depended on thickness, with the thinnest radicular bone associated with greater postoperative bone loss. The mean bone loss for full- and partial-thickness flaps was 0.62 mm and 0.98 mm, respectively.

In animal studies,^5,6 wound healing after pedicle flap surgery was found to occur in four stages:

– adaptation stage (zero to four days) characterized by a fibrin clot with polymorphonuclear leukocytes between the flap and the crestal bone;

– proliferation stage (four to 21 days) with granulation tissue invading the fibrin clot, fibroblasts appearing on the root surface (six to 10 days), apical epithelial migration (10 to 14 days) and osteoclastic activity (four to 14 days) with an average of 1 mm of crestal bone resorption;

– attachment stage (21 to 28 days) characterized by collagen and cementum formation, as well as peak osteoblastic activity;

– maturation stage (28 to 180 days) with new periodontal ligament fibers orienting perpendicularly to root surfaces.

In general, repair consisted of a combination of connective tissue attachment (2.1 mm) and long junctional epithelium (2.0 mm). Histologic analyses revealed minimal tissue destruction and rapid repair.

Lateral sliding flaps. Although the term "lateral sliding flap" was introduced first by Grupe and Warren,⁷ Miller and Allen⁸ have noted that that term now generally refers to the laterally positioned pedicle graft, or LPPG. An LPPG cannot be performed unless there is significant gingiva lateral to the recession site. A shallow vestibule also may jeopardize outcomes. Although the use of the LPPG provides an ideal color match, it often is inadequate for the treatment of multiple recessions.

The use of pedicle grafts to correct mucogingival defects also has been proposed, using an edentulous area as a donor site.⁹ The procedure is particularly useful in cases in which the attached gingiva on facial surfaces of two or three consecutive teeth is inadequate. That technique involves developing partial-thickness flaps around the involved teeth and sliding the entire flap one-half tooth width, while placing the interdental papillary tissues over the buccal surfaces of the affected teeth.¹⁰

Cohen and Ross¹¹ proposed a double-papilla repositioned flap to cover defects in which an insufficient amount of gingiva is present or in which there is an inadequate amount of gingiva in an adjacent area for a lateral sliding flap. The papillae from each side of the tooth are reflected and rotated over the midfacial aspect of the recipient tooth and sutured. The only advantage of this technique is the dual blood supply and denudation only of interdental bone. The disadvantages may include pulling of the sutures and tearing of the gingival papilla.^11–13

Coronally positioned grafts. Bernimoulin and colleagues¹⁴ first reported the use of a coronally positioned graft, or CPG, subsequent to grafting with a free graft; it is a two-stage procedure. In the first stage, a free autogenous soft-tissue graft is placed apical to an area of denuded root. After healing, the flap is coronally repositioned. The requirements for the success of CPGs include

– the presence of shallow crevicular depths on proximal surfaces;

– approximately normal interproximal bone heights;

– tissue height within 1 mm of the cementoenamel junction, or CEJ, on adjacent teeth;

– adequate healing of the free graft (if performed) before coronal positioning;

– reduction of any root prominence within the plane of the adjacent alveolar bone;

– adequate release of the flap to prevent retraction during healing.

The second stage of the procedure uses a split-thickness dissection with mesial and distal vertical releasing incisions until adequate flap mobility is obtained. The flap is sutured 0.5 to 1 mm coronal to the CEJ and covered with a periodontal dressing.¹⁵

Coronally positioned flaps, or CPFs, were compared with lateral sliding flaps in the treatment of localized gingival recessions.^16,17 In a six-month report, both techniques rendered satisfactory results, and no differences in tissue coverage, sulcus depth or gain of attached gingiva were reported. An average of 2.7 mm of soft-tissue coverage was obtained, with average recession coverage of 67 percent. The only difference between the two techniques was an increase in root exposure of approximately 1 mm at the lateral sliding flap donor site, while no additional recession was observed with the CPF. Results were stable for three years.

Two kinds of autogenous grafts can be used for root coverage; one has an epithelialized layer, while the other does not or has only a small epithelialized collar.

Allen and Miller¹⁸ used single-stage CPFs in the treatment of shallow marginal recession. The Miller Class I defects had a minimum keratinized tissue width of 3 mm, with recession between 2.5 mm and 4 mm. The technique consisted of citric acid root treatment, a split-thickness flap extending into the vestibule and surface gingivoplasty of the papillae to produce a bleeding bed. Flaps were sutured into position and dressed. Complete root coverage was attained in 84 percent of the sites, with a mean root coverage gain of 3.2 mm. Similarly, Harris¹⁹ reported a 98 percent success rate of root coverage in Class I defects using the CPG technique.

Tarnow²⁰ described the semilunar CPF technique. An incision is made that follows the curvature of the free marginal gingiva and extends into the papillae, staying at least 2 mm from the papilla tip on either side. The incision is made far enough apically to ensure that the apical portion of the flap rests on bone after repositioning. A split-thickness dissection of the flap is made, and the flap is repositioned and held in place with light pressure and a periodontal dressing. The advantages of this technique include no tension on the flap after repositioning, no shortening of the vestibule, no reflection of the papillae (thereby avoiding esthetic compromise) and no suturing.

Free autogenous soft-tissue grafts. Both the epithelialized palatal graft and the subepithelial connective tissue graft, or CTG, offer a more versatile solution for root coverage than do the laterally positioned or coronally positioned pedicle flaps. There is an adequate amount of donor tissue, a shallow vestibule does not compromise the procedure, and multiple recessions can be treated. Two kinds of autogenous grafts can be used for root coverage; one has an epithelialized layer, while the other does not or has only a small epithelialized collar.

Free epithelialized autogenous gingival grafts. Sullivan and Atkins²¹ were the first to explore the feasibility and healing of free gingival grafts, or FGGs. This procedure involves preparing a recipient site by using supraperiosteal dissection to remove epithelium and connective tissue to the periosteum.

Some of the common areas for donor material include edentulous ridges, attached gingiva and palatal gingiva. Donor tissue should be approximately 33 percent larger than the anticipated healed graft due to shrinkage during healing.²² The grafts used should be approximately 0.8 to 1.3 mm thick to ensure that there is an adequate connective tissue component.²³

In a two-year study comparing grafted sites with nongrafted sites, Dorfman and colleagues²⁴ found that plaque control was more important than the width of the attached gingiva in determining eventual breakdown and recession. They also found that the using FGG was a predictable way to increase the width of the attached gingiva. In a follow-up study two years later, they reported similar results, with the exception that 10 percent of the nongrafted sites showed additional soft-tissue recession compared with grafted sites with equivalent plaque scores.²⁵

Holbrook and Ochsenbein²⁶ have used FGG as a single-step procedure to cover denuded root surfaces. The recipient bed is extended one tooth width lateral to the denuded roots and 5 mm apical to the gingival margin of the denuded root. They suggested that donor tissue cover the gingival bed and extend at least 3 mm apical to the margin of the denuded root, using a graft of approximately 1.5-mm uniform thickness. In 50 randomly selected cases, recessions less than 3 mm had 95.5 percent root coverage, recessions of 3 to 5 mm had 80.6 percent coverage, and recessions more than 5 mm had 76.6 percent coverage.

Miller²⁷ described a technique for root coverage using a free soft-tissue autograft with citric acid treatment. Predictable root coverage depended on the severity and classification of the gingival recession. After root planing, citric acid was applied and then was followed by horizontal incisions at the CEJ level to preserve the interdental papillae. Vertical incisions were made at proximal line angles of adjacent teeth to facilitate the completion of the bed preparation. A thick palatal graft with a thin layer of submucosa was placed on a moderately bleeding bed and stabilized with sutures at the papillary and apical ends of the graft extending into periosteum. Results of 100 consecutively placed grafts showed 100 percent root coverage in Class I defects and 88 percent coverage in Class II defects. The average root coverage for all sites was 3.8 mm with a mean clinical attachment gain of 4.5 mm.

In an attempt to increase the success rate of root coverage, many clinicians have attempted to combine different procedures.

Although Miller²⁷ reported a combined 90 percent success rate in achieving 100 percent root coverage, his 100 cases comprised 94 in the mandible and only six in the maxilla. Other authors reported a root coverage success rate of only 36 percent¹⁶ and 44 percent.¹⁴

Connective tissue autogenous grafts. The use of CTGs for root coverage first was reported by Langer and Langer²⁸ A partial-thickness flap with two vertical incisions was elevated on the recipient site, followed by placement of the graft, which was collected from the palate by a double parallel incision technique. The flap was positioned coronally to attempt to cover the graft and so it could benefit from a double blood supply. Langer and Langer reported an increase of 2 to 6 mm of root coverage in 56 cases over four years.

Raetzke²⁹ described an envelope technique for obtaining root coverage using CTGs. In that technique, the collar of marginal tissue around a localized area of recession was excised, the root was débrided and planed, and a split-thickness envelope was created around the denuded root surface. The graft was collected from the palate by means of the double parallel incision technique. The CTG was placed in the previously created envelope, covering the exposed root surface. Overall, 80 percent of the exposed root surfaces were covered. Similarly, Allen³⁰ reported an 84 percent success rate for root coverage using that same technique.

Jahnke and colleagues³¹ compared the results of FGGs and CTGs for root coverage in nine patients. They selected paired defects and assessed them preoperatively and at three and six months postoperatively. Root coverage averaged 43 percent for the FGG group and 80 percent for the CTG group. Borghetti and Louise,³² in their split-mouth controlled clinical study, reported a 70 percent success rate for root coverage at one year postoperatively.

Most of the studies that used the CTGs for root coverage did not attempt to remove the epithelial collar from the graft, but when Bouchard and colleagues³³ did, no additional statistically significant benefits were observed (65 percent root coverage with the epithelial collar and 70 percent root coverage without).

When Paolantonio and colleagues³⁴ compared the root coverage from CTG with that from FGG, they found in a five-year postoperative study that CTG had an 85 percent success rate, while the FGG had only a 53 percent success rate. They concluded that CTG is a long-term predictable procedure for root coverage.

A variety of techniques have been used to obtain CTG, including parallel incisions and free gingival knife methods, with no significant difference in the percentage of root coverage.³⁵

Combination of one or more techniques. In an attempt to increase the success rate of root coverage, many clinicians have attempted to combine different procedures. Nelson¹² used CTG with a double pedicle graft. A free CTG first was placed over the denuded root surface, followed by a double pedicle graft to partially cover the CTG. Twenty-nine defects were treated with that technique and monitored for four years, at which time the mean root coverage was 88 percent (7–10 mm of recession), 92 percent (4–6 mm of recession) and 100 percent (3 mm recession). Harris¹³ modified Nelson’s technique with a split-thickness pedicle graft to cover the CTG. Thirty Miller Class I and Class II defects were selected, and the mean root coverage was 97 percent.

Wennström and Zucchelli¹ compared a CPF procedure to a combination of a CPF procedure and a CTG procedure. A total of 103 Miller Class I and Class II defects were treated. At a two-year postoperative evaluation, the success rate for the combination group was 98.9 percent, while the success rate for the control group was 97.0 percent. The authors concluded that the CPF/CTG combination procedure (as shown in the figure) was the treatment of choice for achieving root coverage.

View larger version (100K): [in this window] [in a new window]   Figure. Subepithelial connective tissue graft procedure. A. Preoperative buccal gingival recession (tooth no. 6). B. Partial-thickness flap elevated and graft sutured in place. C. Flap coronally advanced and sutured. D. At eight weeks postoperative.

	GUIDED TISSUE REGENERATION

TOP ABSTRACT SOFT-TISSUE GRAFTING GUIDED TISSUE REGENERATION CONCLUSION REFERENCES

More recently, the use of guided tissue regeneration, or GTR, has been suggested for the treatment of recession. Tinti and Vincenzi³⁷ first reported a case in which GTR using an expanded polytetrafluoroethylene, or ePTFE, membrane was used to treat recession defects. Cortellini and colleagues³⁸ conducted a histological study that also demonstrated that the root coverage obtained with an ePTFE membrane included new connective tissue attachment and new bone formation.

Different space-making solutions also have been used in combination with nonresorbable membranes (such as titanium-reinforced membranes, gold-bar–reinforced membranes and gold-frame–reinforced membranes) to increase the percentage of root coverage with GTR. In a histological study using titanium-reinforced membranes, there was evidence of new connective tissue attachment and new bone growth after nine months.³⁹ Previous membrane designs resulted in 77 percent root coverage.⁴⁰

Roccuzzo and colleagues⁴¹ used ePTFE membranes in combination with miniscrews to add space and create stability; they reported mean root coverage of 84 percent in 12 cases. Jepsen and colleagues⁴² compared titanium-reinforced membranes and CTGs using the envelope technique. They found no statistically significant difference in the two treatment modalities (the mean root coverage was 87 percent for the GTR group and 86 percent for the CTG group). Wang and colleagues⁴³ also compared GTR with subepithelial CTG in 16 patients who had bilateral Miller Class I and Class II recession. They concluded that both treatments showed statistically significant improvement from preoperative to postoperative measurements. The mean root coverage was 73 percent for the GTR group and 84 percent for the subepithelial CTG group.

Different space-making solutions also have been used in combination with nonresorbable membranes to increase the percentage of root coverage with guided tissue regeneration.

To eliminate the need for a second surgical procedure to remove a nonresorbable membrane, the use of various bioabsorbable materials have been proposed. In one study, 48 percent root coverage was obtained using a bioabsorbable polylactic acid softened with citric acid ester, or PLACA membrane.⁴⁴ In another study, the PLACA membrane resulted in a mean root coverage of 64 percent.⁴⁵ In a study comparing the use of a PLACA membrane with the use of a nonresorbable ePTFE membrane, Roccuzzo and colleagues⁴¹ found there were no statistically significant differences in the mean root coverage obtained by either technique (PLACA, 82 percent; ePTFE, 83 percent). Zucchelli and colleagues⁴⁶ had similar results when they compared bioabsorbable with nonabsorbable membranes.

The comparison between the use of GTR and gingival grafting to obtain root coverage has been a controversial subject; Pini Prato and colleagues⁴⁷ compared the results obtained with ePTFE membrane and mucogingival surgical procedure (a two-step procedure involving an FGG and a CPF). They reported mean root coverage of 72 percent for the GTR procedure vs. mean root coverage of 70 percent for the two-step procedure; the differences were not statistically significant. Harris⁴⁸ also compared GTR with a bioabsorbable membrane with connective tissue with double pedicle graft; the difference was not statistically significant.

The combination of CPF procedures and GTR was assessed in a clinical investigation.⁴⁹ In a six-month split-mouth randomized design, the authors found that there was no statistically significant difference between GTR and CPFs vs. CPFs alone. The mean root coverage was 56 percent and 69 percent, respectively. Another study reported similar results, with no statistically significant differences observed between the two treatment groups.⁵⁰ The latter study, however, reported a slight increase in the width of keratinized gingiva in the connective tissue group. Ricci and colleagues⁵¹ showed similar results after a one-year postoperative evaluation, with no statistically significant differences between treatments (77 percent mean root coverage for the GTR group and 80 percent for the connective tissue group). Harris⁵² combined a CTG with a CPG and compared it with GTR with a bioabsorbable membrane. No differences were observed between groups (92 percent for the GTR group and 95 percent for the connective tissue with CPG group). He also noticed a greater increase in the amount of keratinized gingival tissue for the CTG group.

Trombelli and colleagues⁵³ showed a significant difference in mean root coverage when they compared GTR with a bioabsorbable membrane to a CTG procedure (48 percent root coverage for the GTR group and 81 percent root coverage for the CTG group). They reported a significant increase in the amount of keratinized gingival tissue for the CTG group compared with the GTR group. In a more recent study,⁵⁴ however, when GTR was compared with CTG with CPFs, the authors concluded that in shallow recessions (1.5–3.5 mm) GTR techniques only had a 50 percent root coverage at 12 months postoperatively, while the CTG techniques yielded 82 percent root coverage. Harris⁵⁵ supported the previous conclusion by reporting that 92 percent mean root coverage obtained six months postoperatively had been reduced to 58 percent after evaluations at a mean of 25 months postoperative.

	CONCLUSION

TOP ABSTRACT SOFT-TISSUE GRAFTING GUIDED TISSUE REGENERATION CONCLUSION REFERENCES

 
The treatment of gingival recession can be accomplished with a variety of different procedures. The combination of CTG with a CPF, however, has been shown to demonstrate the highest success. GTR also can be used to treat recessions, particularly when patients are reluctant to consent to providing palatal gingiva donor sites.

View larger version (113K): [in this window] [in a new window]   When this article was written, Dr. Kassab was a clinical assistant professor, Department of Periodontics and Endodontics, School of Dental Medicine, State University of New York at Buffalo. He now is a periodontist, The Forsythe Institute, 140 The Fenway, Boston, Mass. 02115, e-mail "mmkassab@hotmail. com". Address reprint requests to Dr. Kassab.

View larger version (99K): [in this window] [in a new window]   Dr. Cohen is a professor, Department of Periodontics and Endodontics, and the director, Postgraduate Periodontics, School of Dental Medicine, State University of New York at Buffalo.