Flap Surgery in Periodontics
by Dinh X. Bui, D.D.S., M.S.

Flap Surgery in Periodontics
Neuman claimed the introduction of the mucoperiosteal flap in 1911. The technique included a intrasulcular incision and two releasing incisions on both side of the defect area. Flap was raised up to the level of apices of the teeth. Gingival margin was trimmed approximately 2mm in the area of deep pockets with bone removal. Widman introduced the Widman flap in 1918. He described a trapezoidal flap with two vertical releasing incisions at the midline of the teeth and the reverse bebel incision made parallel to the surfaces of the teeth 1mm from the free gingival margin and extending to the alveolar crest. The flap assume a scallope appearance. Bone removal was carried out for better soft tissue adaptation. As in Neuman’s procedure, the flaps were sutured back by individual interproximal suture. Cieszynski, however, was credited with the introduction of reverse bevel incision. Zentler introduced the mucoperiosteal flap in the U.S.A. in 1918, with the idea that the procedure was to allow access for debridement and elimination of granulation tissue as well as osseous removal by chisels. As we can see flap surgery was done at the beginning but for the difference purpose of bone removal and pocket elimination. Apparently the first description of the flap procedure for the purpose of reattachment was given by Kirkland in 1931. He used the basic gingival mucoperiosteal flap design by Neumann in 1920 for initial flap, but instead of trimming the flap for surgical pocket elimination, he attempted to eliminate the crevicular epithelial lining and the inflamed connective tissues by curettage of the flap. His method has been used as “open subgingival curettage.” Flap surgery became popular after 1935, when Kronfeld in his autopsy study of which he stated that the bone adjacent to the periodontal pockets was neither necrotic nor infected but rather destroyed by an inflammatory process. Orban later supported this finding in his own studies. The main culprit of the disease now has shifted to the soft tissue. Gingivectomy became popular; however, its problem of excising the attached gingiva, the frenum attachment, and the creation of shallowed vestibular trough have prompted the periodontists to arrive at new technique and procedures for pocket elimination. In 1954, Nabers described the “repositioning of the attached gingiva.” For the first time, a mucoperiosteal flap was apically positioned after treatment. He utilized one vertical releasing incision which is placed mesially to the area of the deepest pocket. Later in 1957, he introduced the inverse bevel incision of which he called the “repositioning incision” which includes the internal incision from the gingival margin to the alveolar crest. This incision, he stated, would permit an easier flap reflection and result in a thinner gingival margin. In that same year, Ariaudo and Tyrrell modified Nabers’technique and recommending two vertical releasing incisions instead of just one to facilitate the mobilization of the flap. At this point, the only difference from the flap design of Widman is the apical positioning. Finally, in 1962, Friedman published the technique in his paper and coined the term “apically reposition flap”. Today, the word “reposition” is replaced by the term “position” since reposition means place the flap back to where it was before
A flap is defined as a loosened section of tissue separated from the surrounding tissue except at its base. Flap surgery has been characterized extensively by Carranza and Ramjford in 1979. In 1979, Carranza classified flap as full thickness flap and partial thickness flap. Full thickness flap is surgical procedure of which all soft tissue and the periosteum are reflected. Partial or split thickness flap is an elevated flap which includes only epithelium and the layer of underlying connective tissue. Periosteum was not part of a split thickness flap. In 1990, Carraza again classified flap according to their placement at the conclusion of a surgical procedure. They are repositioned, positioned, or displaced flapes (those that can be placed apical, coronal, or lateral to its original position. Unreposition or unreplaced flap are those that are placed in the position they were found before the surgery. Another classification of flap types were done by Ramfjord in 1979, of which he classified periodontal flap surgery procedure according to the main purpose of the procedure such as pocket elimination flap, reattachment flap surgery, and mucogingival repair. Flap for pocket therapy incuded the modified widman flap, the undisplaced (unrepositioned) flap, and the apically displaced flap.

The modified widman flap is the one that used for exposing the root surfaces for instrumentation and debridment and for removal of poket lining. It is not intended to eliminate or reduce pocket depth, though the reduction does occur dure to tissue shrinkage following healing. It does not intend to remove the pocket wall but does eliminate the pocket lining. The internal bevel incision start close (no more than 1 to 2 mm apical) to the gingival margin and follows the scalloping of the gingival margin. Ramfjord and Nissle in 1974 coined the term modified Widman flap though the procedure was employed by Morris in 1965 and was termed the unrepositioned mucoperiosteal flap. Morris in 1965 has described this flap as “the simple mucoperiosteal flap, combined with the inverted bevelled incision and osseous resection.” The flap utilized three incisions: the internal bevel incision starting 1 to 1.5 mm away from the gingival margin and follows the gingival margin scalloping, the crevicular incision from the bottom of the pocket to bone, circumscribing the triangular wedge of tissue containing the pocket lining, and finally, after the flap is reflected, the horizontal incision is placed in the interdental spaces, coronal to the bone, with a curette or an interproximal knife, and the gingival collar is removed. Extensive longitudinal studies has been made to compare the Widman procedure to the curettage technique and the pocket elimination methods that included bone contouring when needed. It is the seven years follow ups longitudinal studies. The investigators reported approximately similar results with three method tested. Pocket depths were best maintained at shallower levels with the Widman flap and the attachment level remained higher with the Widman flap. Ramfjord in 1974 reviewed the present status of the modified Widman procedure and detaily describe the procedure. He notes that the key to success of the procedure is to create and maintenance of the biologically acceptable root surface. The advantage of the procedure is to coapt the tissues to the root surfaces, access to the root sufaces, esthetic result, less likely to produce root sensitivity and caries, and a favorable environment for oral hygiene maintenance. Disadvantages include flat or concave interproximal soft tissue contour which required meticulous oral hygiene in the area. Smith and Svoboda et al (1984) evaluate the MWF and concluded that removal of the sulcular epithelium during the periodontal surgery provided no therapeutic advantage. The procedure is indicated for deep pocket, infrabony pocket, and when minimal recession was desired. The end result is the establishment of an intimate postoperative adaptation of healthy collagenous connective tissue to tooth surfaces and provides access for adequate instrumentation of the root surfaces and immediate closure of the area. In 1977, Ramfjord published the paper discussing the present status of the modified widmen procedure and detaily discussing the entire technique. Afterward, various studies by Caffesse, Castelli, and Nasjleti to investigate the vascular response to the modified widman flap surgery was carried out. In October 1987, the result of a longitudinal study comparing scaling, osseous surgery and modified widman procedures was published. This study documented the difficulty in achieving primary flap closure after modified widman flap surgery. Only 26.8% of primary closure was achieved. There was a tendency for the sites that receives the modified widman therapy to have a higher percentage of crateres during healing. However, at six weeks, there were no meaningful differences between the modified widman and the scaling and root planing with osseous surgery. The result from this study indicated that with three month maintenance and recalls, both the modified Widman and osseous surgery are effective for pocket reduction, and each will produce a slight gain of clinical attachment over one year. Next, the undisplaced flap is to provide accessibility for debridement and is an excisional procedure of the gingiva to eliminate the pocket. It differs from the modified Widman is that soft tissue pocket wall was removed with an initial incision. Enough attached gingiva must be present since it is an internal bevel gingivectomy. In the palatal area, the undisplaced was used since the palatal tissue is all attached, keratinized tissue and has none of the elastic properties associated with other gingival tissues. The palatal tissue, due to the above reasons, cannot be apically displaced, nor can a partial thickness flap can be accomplished. Thus the initial incision is very important in term of location of placement since it must be designed such that when the flap is sutured, it is precisely adapted at the root bone junction. Initial incision is varied depends on the thickness of the palatal tissue. Normally, the internal bevel incision is used with the incision placed further away from the gingival margin. If the tissue is thick, the horizontal gingivectomy incision is made, following by an internal bevel incision that starts at the edge of this incision and ends on the lateral surface of the underlying bone. When the flap is approximate for suture, bone must not be exposed to stimulate primary healing response. The apical portion of the scalloping should be narrower than the line angle area, since the rounded scallop will result in the flap that cannotfit snugly around the root upon suturing. Finally, The apically displaced flap is to improve accessibility for debridement and eliminate the pocket. It is designed for pocket elimination via repositioning the soft tissue wall of the pocket. It can also be used to preserve or widening the zone of the attached gingiva. It can utilized the partial (mucosal) or full thickness (mucoperiosteal) flap design. The split thickess flap design is more complex but can be more accurately positioned and sutured in an apical position using the periosteal suturing technique. Again, three incision is used: the reverse bevel incision, the crevicular incision, and the horizontal releasing incision. Flap is refected, area is debrided, and tissue apically displaced to eliminate the pocket. The flap must be elevated past the mucogingival line junction to provide adequate mobility to the flap for its apical displacement. Apically positioned flap surgery can be used alone or combine with osseous surgery. The indication for the apically positioned flap without osseous surgery are suprabony and infrabony pockets, diseased roots which are located subgingivally, crown lengthening procedures for cosmetic enhancement and restorative treatment, and finally the need to increase keratinized tissue. The contraindications are: compromised esthetic and anatomical preclusion. The major advantages of the procedure are reduction of probing depth, preserving or increasing the presurgical zone of gingiva, facilitation of healing, accessibility to bone, roots, furcations, subgingival caries, and other anatomical aberrations, controlling the tissue placement, and finally its usefulness in conjunction with other treatment modalities. The weakness of the procedure is that it limits the treatment of intrabony defects. The therapeutic endpoints for success are: reduced probing depth, properly prepared roots, adequate clinical crowns, increased keratinized tissue, improve cosmetics, and facilitate maintenance care. Similarly, when combine with osseous surgery, the procedure allows for further reduction or elimination of infrabony pocket and eliminate anatomic aberrant which rendered the site susceptible for plaque and bacterial accumulation.
Healing of the flap surgery has been carried out extensively in numerous histological and longitudinal studies. The healing sequence is significantly affected by the oral hygiene of the patient, the tissue adaptation following closure, the handling of the flap due to surgery. Oral hygiene inadequacy leads to plaque and bacterial product in the area which cause infection and compromised the normal healing. Tissue adaptation distinguished the healing by primary intention and that of secondary healing intention. The most common pattern of healing is by secondary intention. The epithelial adhesion occlusal to the base of the original pocket is seen at times, but more frequently the collagen adhesion immediately apical to the newly adhering junctional epithelium but occlusal to the marginal alveolar crest. In the infrabony portion of the periodontal lesions, simultaneous and/or sequential deposition of repair cementum, functionally oriented ligament fibers and narrowing of the vertical defect by osteogenesis. It is possible that supracrestal healing following flap surgery is a connective tissue adherence over a limited space immediately apical to the junctional epithelial adherence. Another pattern of healing in connective tissue is the splicing of fiber ends from the tooth surface with new fibers from the healing flap wound edge. This occur when the root surface is not completely devoid of periodontal tissue (whether due to pathological lesion or mechanical/chemical debridement ). This type of healing can be classified as repair rather than regeneration.
Histologic observation also has indicated that there may be a newly cementumlike material to be deposited against the tooth coronal to the crest. This newly deposited cementum is cellular, not unlike bone, and be best described as repair cementum (Dragoo and Sullivan 1973, Hawley and Miller 1975). Listgarten (1972) speaks of this cementum as devoid of well defined fiber bundle. Again, since the new regenerative tissue is not exact the same as the original, the healing process can best be described as repair rather than regeneration. In a histologic examination of the 13 block sections of teeth and surrounding tissues which were removed at varying time interval form the mouth of six patients in the study of the mucoperiosteal flap healing carried out by Theodore H. Dedolph and Henry B. Clark in 1958 reveals that at 3 weeks the epithelial attachment was complete, the attachement of periodontal membrane fibers and other connective tissue elements was restored, and the inflammatory response was mild or absent. The appearance was indistinguishable from that of the control sections and from that of the four week experimental sections. The flap design should be such that it should has sufficient size to provide maximum visibility, wide access, and a broad surface of bone on which the flap margin may rest for optimum healing. Another study in 1972 by Dale L. Wood, Phillip Hoag, and O. Walter Donnenfeld, and Leon Rosenfeld reveals of the loss of crestal radicular bone after both the full thickness and the partial thickness flap. The mean bone loss for the full thickness flap was .62 mm, which was statistically significant (p >.01). The mean bone loss after the partial thickness flaps was .98mm which was also significant. Thus the bone loss was greater with the use of partial thickness flap. Other study has investigated the vascular response and the healing of the reverse bevel flap. In the study in monkey by Caffesse and Ramfjord and Nasjletti in 1968, healing following reverse bevel periodontal flap surgery has been characterized by first, second, or third intention, depending on the state of flap adaptation to teeth. Epithelialization regenerate from the border of the flap is delayed 2 to 4 days due to the stunning effect of the surgery. Flap separation on top of the periosteum (split flap) will heal faster than the mucoperiosteal flap. Finally, the transient lowering of the attachment level and bone resorption at the alveolar crest 3 to 4 weeks following flap surgery tend to heal back to the presurgical level within 10 weeks after the surgery. Finally, Wirthlin, in his review of the current status of new attachment therapy, he stated that there are four basic forms of periodontal therapy used for elimination of the pocket. These are: shrinkage, excision, healing by scar, and new attachment. The shrinkage and excision and healing by scar is demonstrated by examine the tissue side, whereas the analysis of repair system reveals new attachment on the tooth side of the periodontal lesions.
Flap surgery has been done as of the beginning of the century. The technique has evolved very little from the beginning, though the procedure were carried out for different purpose. Regardless of different methodology, the healing in flap surgery can be classified as repair, rather than regeneration.

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References

1. Caffesse, R.G. Resective procedures. Proceedings of the world workshop in clinical periodontics, 1989.

2. Caranza, Newman. Textbook of Clinical Periodontology, WB Saunders, 1996.

3. Morris, M.L. The unrepositioned muco-periosteal flap, Journal of Periodontics: 3: 147, 1965.

4. Stahl, S.S. Repair or regeneration following periodontal therapy? Journal of Clinical Peridontology: 1979: 6: 389-396.

5. Levine, Leslie. Periodontal flap surgery and the gingival fiber retention. Journal of Peridontology, 1972: 43: 91-98.

6. Barrington, E.P. An overview of periodontal surgical procedure, Journal of Periodontology: 52: 518, 1981.

7. Dedolph, T.H., Clark, H.B. A histological study of mucoperiosteal flap healing. Journal of Oral Surgery: 16:367, 1958.

8. Wood, D.L., Hoag, P.M., Donnenfeld, O.W., Rosenfeld, L.D. Alveolar crest reduction following full and partial thickness flaps, Journal of Periodontology, 43:141, 1972.

9. Caffesse, R.G., Ramfjord, S.P., Nasjleti, C.E. Reverse bevel periodontal flaps in monkeys. Journal of Periodontology, 39: 219, 1968.

10. Levine, H.L., Stahl, S.S. Repair following peridontal flap surgery with the retention of gingival fibers. Journal of Periodontology, 41:99, 1972.

11. Ramfjord, S.P. Present status of the modified widman flap procedure. Journal of Peridontology, 48: 558, 1977.

12. Caffesse, R.G., Castelli, W.A., and Nasjleti, C.E. Vascular response to modified Widman flap surgery in monkeys. Journal of Periodontology, 52: 1, 1981.

13. Becker, W., Becker, B.E., Ochsenbein, C.O., Kerry, G., Caffesse, R.G., Morrison, E.C., Prichard, J. A longitudinal study comparing scaling, osseous surgery and modified widman procedures. Results after one year. Journal of Periodontology, 59: 351, 1987.

14. Caffesse, R.G., Ramfjord, S.P., Nasjleti, C.E. Reverse bevel periodontal flaps in monkeys. Journal of Periodontology, 39: 219, 1968.

15. Ramfjord, S.P., Nissle, R.R. The modified widman flap. Journal of Periodontology, 45: 601, 1974.

16. Wirthlin, M.R. The current status of new attachment therapy. Journal of Periodontology, 52: 529, 1981.