Periodontal Plastic Surgery

Copyright 1999 Journal of the California Dental Association.

As the demand for esthetic dentistry has increased, dentistry has developed techniques to meet this demand. Periodontal plastic surgery has been part of this effort. This article outlines the scope of periodontal plastic surgery procedures to aid the dental team in diagnosis and treatment of esthetic dental cases.

Until relatively recently, periodontal therapy was limited to the prevention, diagnosis, and treatment of diseases of the supporting and surrounding tissues of the teeth. Periodontal surgical procedures were typically resective in nature. The goals of these procedures were to debride the roots and increase the cleansability of the teeth by reducing pocket depths and modifying furcation defects, often via root removal. The value of this form of therapy on the overall retention of teeth is high, and it remains valid as a treatment modality.¹ The unfortunate consequences of this mode of therapy include increased root exposure and decreased papillary height due to apical repositioning of the osseous crest and free gingival margin. As society has become increasingly focused on individual beauty and the retention of youth as measures of self-worth, these side effects of periodontal surgery are no longer acceptable to the majority of patients or practitioners due to the negative effects in the esthetic zone. The past 20 years have seen an increasing focus on esthetic procedures in all areas of clinical dentistry, and periodontics is no exception.² The field of periodontics is continually expanding as regenerative procedures are developed in an attempt to replace missing hard and soft tissues and to prevent esthetic compromise.

Periodontal plastic surgery has as its primary goal the restoration or enhancement of the esthetic component of the supporting and surrounding tissues of the teeth or their substitutes. This can be accomplished by reshaping the existing tissues to a more pleasing form as well as by grafting or implanting natural or synthetic devices and materials to replace missing tissues or teeth.

The majority of periodontal plastic surgery procedures are undertaken to treat or prevent the following conditions and can be classified as such:

* Marginal recession (root coverage);

* Ridge deficiency (ridge augmentation);

* Ridge collapse after extraction (ridge preservation);

* Excessive or asymmetrical gingival display and biologic width invasion (crown lengthening); and

* Esthetic defects around dental implants (hard and/or soft tissue grafting).

The field of periodontal plastic surgery has become broad in scope. It includes procedures in which autogenous and non-autogenous materials are used for surgical augmentation of deficient areas, as well as the surgical reshaping of autogenous tissues to improve their appearance. For the sake of brevity, this article will present only techniques that manipulate the patient's autogenous tissues and exclude procedures utilizing membranes or sources of tissue other than the patient. The article will further focus on soft tissue grafting versus hard tissue grafting. The intent of this article is to present an overview of these periodontal plastic surgery techniques in order to expand multidisciplinary treatment planning options for the dental team.

Diagnostic and Treatment Planning Considerations

The oral esthetic zone consists of three components:

* The lips, which delineate that portion of the mouth that is on display;

* The gingiva, which frames and defines the shape of the individual teeth; and

* The teeth, which are the ultimate focus for an observer’s assessment of color, contour, position, and shape.

Treatment planning for an esthetically pleasing smile involves bringing the three components of the esthetic zone into harmony. All dentists learn this "ideal" relationship when they are taught to set denture teeth and wax denture bases.

Figure 1. Smile illustrating harmony between the components of the oral esthetic zone (Restoration by Dr. Michael Hack).

In Western culture, this so-called ideal setup has the following characteristics³ (Figure 1). On smiling, the upper lip line follows the level of the gingival margins of the maxillary teeth and exposes the entire length of the teeth and up to 3 mm of gingiva. The lower lip line follows the incisal edges of the maxillary teeth. The gingival heights of the maxillary central incisors mimic one another. The lateral incisor gingival margins are slightly coronal to that of the central incisors and are bilaterally symmetrical. The cuspid margins are at the same level as the central incisors and equal to each other. The tissue margins extending to the distal are more coronally positioned than the cuspid margins, are symmetrical from side to side, and rise superiorly as they proceed distally. The interdental embrasures are filled with tissue to the contact points. The incisal edges of the maxillary central incisors are even with the cusp tips of the canines, and the incisal edges of the lateral incisors are slightly apical to this line. The buccal cusp tips of the maxillary posterior teeth rise slightly as they proceed to the distal as a result of the Curve of Spee. As the teeth extend posteriorly and laterally, they fill the vestibules to the corner of the smile.

When a patient is concerned about deviations relative to this ideal position of the teeth or gingiva, dental therapy can be used to correct these variations and more closely approach the ideal. A comprehensive treatment plan to address the patient's concerns may require interplay between several areas of clinical dentistry. It is incumbent upon the clinician to recognize the possibilities and limitations of restorative dentistry, periodontics, orthodontics, orthognathics, and implantology in the multidisciplinary treatment of these cases.

Adjunctive Periodontics for Esthetic Dentistry

The color and shape of the periodontal tissues greatly influence the esthetics of the smile. The health of the tissue, as well as the type of tissue (mucosa, keratinized gingiva, or palatal masticatory mucosa) and the presence of dark objects in the alveolus or soft tissues (implants, alloy, metal crown margins, or dark roots), influences color. Gingival shape is also contingent upon the health of the tissue, as well as the position of the free gingival margin; the volume and height of the papilla; and, in the absence of teeth, the volume and height of the ridge.

Root Coverage

Figure 2. Patient with a high smile that exposes a discrepant architecture of the gingival margins due to recession.

Root exposure resulting from apical recession of the marginal tissues can create esthetic concerns for a patient (Figure 2). As the length of the teeth increase, there is loss of gingival symmetry as well as increased sensitivity, susceptibility to caries, and concern over the retention of the teeth. Restorative coverage of the root can reduce sensitivity or treat caries but cannot decrease the length of the clinical crown, restore the lost periodontal support, or prevent future recession.

Figure 3. Same patient as in Figure 2 after connective tissue grafts have been done for root coverage. Symmetry has been restored to the gingival margins. Replacement of the restoration on tooth No. 5 is planned for an improved color match.

The clinical goals of root coverage procedures are to replace the tissues lost due to recession, effect an attachment of the restored tissues to the root of the tooth, reduce thermal and touch sensitivity, discourage future recession, and improve the esthetics of the area when the grafted tissues blend with the adjacent tissue color, texture, and contour (Figure 3).

Three forms of root coverage have been presented in the literature. The free autogenous graft (thick gingival grafts^4,5 and connective tissue grafts^6,7), pedicle flaps (lateral⁸ and coronal⁹), and guided tissue regeneration with both nonresorbable¹⁰ and resorbable¹¹ membranes.

Pedicle flaps and guided tissue regeneration have been shown to be viable root coverage procedures, but both techniques have limitations that reduce their clinical applicability. Free autogenous grafts exhibit a very high level of clinical utility. Compared to pedicle flaps and guided tissue regeneration procedures, free autogenous grafts are much less dependent upon the characteristics of the adjacent tissues for success, these grafts can create a localized thickening of the alveolar housing to aid in the prevention of future recession, and several adjacent teeth with recession can be treated simultaneously.

Nabers¹² introduced the free gingival graft in 1966, and Sullivan and Atkins¹³ made further refinements in 1968. As originally described, the graft was palatal masticatory mucosa (epithelium and connective tissue) approximately 1 mm thick. This type of graft was found to be unpredictable for covering roots due to sloughing of the grafted tissue over the avascular root surface. The thin grafted tissue bridging the root could not maintain tissue viability for the period of time necessary to establish a new collateral blood supply. In the early 1980s, Miller⁴ and also Holbrook and Ochsenbein⁵ described a technique to graft thicker tissue, approximately 2 mm, from the surface of the palate over the exposed root. This thicker tissue could survive the early lack of nutrition to the area over the root. This allowed the re-establishment of a vascular complex in the graft and retention of the tissue bridging the avascular root surface. Good biologic results were reported with this technique.¹⁴ However, these grafts tend not to blend with the adjacent tissues and are readily identified as thicker and lighter in color. This can cause an esthetic compromise. In 1985, Raetzke⁶ and then Langer and Langer,⁷ described the use of connective tissue grafts for root coverage. In this technique, the epithelial component is eliminated from the graft, and palatal connective tissue is transplanted into an envelope-like pouch prepared at the recipient site. This pouch provides a dual blood supply to the

Figure 4A. Palatal donor site for a connective tissue graft. The graft has been removed and a strip of connective tissue approximately 1.5 mm wide has been left coronal to the donor site to aid in primary closure. Figure 4B. The connective tissue graft free of epithelium.

graft from the superior and inferior connective tissue surfaces in contact with the graft. The retained superior flap also maintains the esthetics of the original tissues and acts as a source for the epithelial cells that migrate over the exposed portion of the connective tissue graft. These grafts are very successful in covering the root and blending with the adjacent tissues for a highly esthetic result.

The connective tissue donor site uses a trapdoor approach on the palate to harvest a connective tissue graft free of epithelium. A single horizontal incision is made on the palate parallel to the free gingival margin and approximately 3 mm apical to the margin (Figure 4). The incision can be extended from the second molar to the nasopalatine papilla if necessary

Figure 5A. Primary closure of the palatal donor site with 5-0 gut sutures. Figure 5B. One-week healing of the palate illustrating typical slight connective tissue exposure with minimal discomfort for the patient. Figure 6A. Slight wide recession on Nos. 7 and 8 with moderately wide recession and a lack of attached gingiva on No. 9. Figure 6B. Incisions and split thickness flap with papillary preservation. Figure 6C. Connective tissue graft in place on Nos. 8 and 9. Coronally positioned flap planned for No. 7. Figure 6D. Six-0, 7-0, and 9-0 microsutures used for flap closure and graft stability. Figure 6E. One-year result with root coverage to the cementoenamel junction, increased dimensions of the gingiva, and inconspicuous blending of the grafted tissue into the site.

to allow improved access to the connective tissue. With the primary flap elevated, a connective tissue graft approximately 1.5 mm thick is removed and trimmed as necessary to fit the recipient site. Sutures are placed for primary closure of the palatal access flap. The palate is protected by a custom Omnivac stent for two weeks postoperatively. Utilizing this technique, the palate heals with minimal discomfort or complications (Figure 5).

The roots of the teeth to be covered are prepared by thorough odontoplasty for debridement and reduction of the facial height of contour. This is done using hand instruments and finishing burs. The roots are then polished with a nonfluoride prophy paste. Chemical modification of the roots is then done with tetracycline or citric acid to remove the smear layer and expose collagen fibrils of the dentin matrix. This will allow subsequent interdigitation of these fibrils with those in the connective tissue graft.¹⁵

The recipient site is prepared by creating parallel horizontal incisions that extend one papilla width beyond the affected teeth on the mesial and distal (Figure 6). The distance between these incisions is 1.0 to 1.5 mm to allow slight coronal positioning of the flap over the graft. A split thickness dissection is carried apically far enough to allow free movement of the flap in the coronal direction. The connective tissue graft is slid between the primary flap and connective tissue and sutured into place with a single 6-0 stay suture in each papilla. Seven-0, 8-0 and 9-0 sutures are used as necessary as secondary and tertiary sutures to facilitate primary closure and graft stability. A periodontal dressing covers the recipient site for one week.

Evolution of the surgical technique to include the surgical microscope and microsurgical instrumentation has increased the precision of these procedures. Microsurgery techniques decrease trauma to the tissues and allow improved surgical closure, thereby improving the outcome and reducing patient discomfort at the donor and recipient sites.¹⁶

The question remains, does the technique just create a pocket where there had previously been recession. If not, then what sort of attachment occurs between the graft and the root surface? Several authors have shown clinical probing depths consistent with attachment of the graft to the root surface.¹⁷ Histologic case reports of an autogenous graft¹⁸ as well as guided tissue regeneration¹⁹ have shown formation of new bone and connective tissue attachment on the root in the area previously exposed to the oral cavity.

Ridge Augmentation and Preservation

The position of the free gingival margin of a tooth can be corrected with a connective tissue graft, as shown in the prior section. The root of the tooth acts as support for the grafted tissue as well as for the alveolar bone and soft tissue housing. Removal of a tooth results in collapse of the alveolus and causes a shift of what had been the free gingival margin in an apical and lingual direction.²⁰ Esthetic restoration of missing teeth with pontics or implants often will require reconstruction of this lost tissue prior to placement of the prosthesis. Ridge augmentation techniques have been developed that allow predictable replacement of alveolar tissues lost after the removal of teeth. Ridge preservation techniques, performed simultaneously with tooth removal, can prevent the natural collapse of the ridge and will limit the loss of bone and soft tissue.

Ridge Augmentation

Collapsed ridges can be built up in a variety of ways: soft tissue grafts,²¹ bone grafts,²² guided bone regeneration,²³ alveolar distraction osteogenesis,²⁴ and combinations of these techniques. The anatomy of the defect and the restorative plan aid in the selection and sequence of treatment options. Seibert²⁵ categorized ridge defects based on anatomy:

* Class I, buccolingual loss of tissue width with normal ridge height;

* Class II, apicocoronal loss of tissue height with normal ridge width; and

* Class III, combined buccolingual and apicocoronal loss of tissue resulting in loss of ridge height and width.

Figure 7A. Ridge defect. Seibert class: slight to moderate III. Note scaring from history of apical surgery and apical position of No. 11 relative to No. 6, which will limit vertical augmentation of the papilla. Figure 7B. Two connective tissue grafts laminated for vertical and buccal augmentation. Figure 7C. Five-year result, fixed partial denture with modified ridge lap pontics, compare to ovate pontics in Figure 10C (Restoration by Dr. Bennett Dubiner). Figure 9A. Patient presented with buried implant in place No. 9. Note loss of tissue volume and lack of papilla on the mesial of No. 10. Figure 9B. One-year result after combined epithelium and connective tissue graft followed by a tissue punch exposure of the implant (Restoration by Dr. Paul Hoyt). Figure 10A. Preoperative smile, Nos. 8 and 9 are pontics on a stayplate. Note excessive gingival display due to vertical maxillary excess; inconsistent gingival margin levels and lack of midline papilla due to traumatic loss of Nos. 8 and 9. Figure 10B. Tissue appearance after crown lengthening on Nos. 6 through 11 and connective tissue grafting of the ridge followed by creation of ovate pontic recipient sites for Nos. 8 and 9. Note restoration of the papillae and the lack of inflammation in the tissues. Figure 10C. One-year result, fixed partial denture with ovate pontics. Note symmetrical gingival margins and maintenance of papillary height and volume (Restoration by Dr. Tom Kuhn). Figure 12A. Preoperative view. Teeth Nos. 8, 9, and 10 will be removed due to root resorption and ankylosis. Figure 12B. Resorptive defects on roots. Figure 12C. Tissue plugs in place over bone grafts. Figure 12D. Four-month healing illustrating preservation of the buccal plate. Figure 12E. Five-year postoperative result with fixed partial denture in place (Restoration by Dr. Al Sze).

If a fixed partial denture is planned, connective tissue grafts can be used to restore the missing tissue volume. Slight to moderate Class I and slight Class II defects can usually be corrected in a single surgical procedure. Advanced Class I and most Class II and Class III defects will require multiple staged augmentations to re-establish normal ridge form. When multiple augmentations are necessary, a minimum of three months is required between procedures to allow for revascularization, shrinkage, and maturity of the previous graft. After three months, an assessment is made as to the need for more tissue prior to the final prosthesis. If no further surgery is required, the final fixed partial denture can be undertaken four months postoperatively.

Surgical preparation of the recipient site in small ridge defects is done with a single horizontal incision slightly palatal to the crest of the ridge extending to within 1 mm of the sulcus of the teeth immediately adjacent to the ridge. The incisions then parallel the sulcus as they swing to the facial terminating at the proximal line angles of the adjacent teeth. This type of incision will maintain the preoperative papillary height. If the papillary height or volume is deficient, the incisions are carried into the sulcus and an attempt is made to increase the height and volume of the papillae in conjunction with the ridge augmentation. A split thickness dissection on the facial is carried far enough apically to allow free movement of the superior flap. As the size of the defect increases, vertical releasing incisions into the mucobuccal fold become necessary, as does a split thickness palatal dissection.

Figure 8A. Preoperative ridge defect. Seibert class: moderate III. Figure 8B. Combined epithelium and connective tissue graft for ridge augmentation. Figure 8C. Graft in place prior to flap closure. Figure 8D. Three-month result. Note restoration of tissue volume and blending of graft with the native tissues. Figure 11A. Preoperative view, No. 8 will be removed. Note chronic erythema and apical position of gingival margin secondary to biologic width invasion, fistula near the apex, and surgical scar from prior apical procedure. Figure 11B. Radiograph illustrating periapical radiolucency and evidence of prior bone graft near the apex. Figure 11C. Connective tissue graft in place after thorough degranulation of socket and placement of a bone graft to preserve the buccal plate. Figure 11D. Three-month healing with provisional in place. Note full buccal contour of alveolus and restoration of marginal symmetry. Apical fistula is sealed (Restoration by Dr. Rebecca Castaneda). Figure 13A. Preoperative view. No. 9 will be removed due to a horizontal root fracture. Note slight apical position of gingival margin No. 9. Figure 13B. Eight-month soft tissue result after tissue-plug ridge preservation followed by an implant. Professional restoration in place and ready to begin the final restoration (Restoration by Dr. Tom Kuhn).

For small defects, connective tissue grafts are harvested from the palate in the same way as a root coverage graft; however, the tissue taken needs to be thicker to restore the volume of the collapsed ridge. If necessary, based on the size of the defect, multiple connective tissue grafts can be laminated onto a deficient ridge during a single surgical procedure (Figure 7). As the defect increases in size, combined connective tissue and epithelium grafts are used to further increase the bulk of the graft and to prevent a coronal shift of the mucogingival junction (Figure 8). Connective tissue grafts are sutured to the underlying periosteum to facilitate positioning and stabilization of the grafts. This technique can also be used to increase the volume of soft tissue around previously placed implants, and it can be helpful in the restoration of papillae adjacent to the ridge (Figure 9).

If implants are planned, the amount of bone in the site will determine the type and sequence of grafting. In early to moderate Class I defects, with adequate bone for implant stability, a connective tissue graft can be placed at the same time as the implant or during the uncovering procedure. In advanced Class I and most Class II and Class III defects, which lack adequate bone for implant stability in an esthetic position, the necessary bone volume should be restored first. This can be done with guided bone regeneration with autogenous particulate bone grafts, monocortical block grafts, or alveolar distraction osteogenesis. Once adequate bone volume is created for implant stability, the soft tissue is assessed for esthetic harmony and augmented as necessary.

Ovate Pontics

When a fixed partial denture will be used to replace missing teeth, an ovate (egg shaped) pontic will create the illusion that the pontic is emerging from the tissue. Esthetically, this is preferable to the display of the modified ridge-lap pontic that may appear as if it is sitting on top of the ridge. After grafting has restored the tissue volume, ovate-shaped pontic recipient sites are cut into the tissue to a depth of 3 mm using diamond burs and/or electrosurgery (Figure 10). The base of an ovate pontic needs to be at least 2 mm away from the alveolar crest to provide enough space for tissue health, which requires 1 mm of connective tissue and 1 mm of epithelium. The provisional restoration is modified into an ovoid shape at the tissue-bearing surface and is placed into intimate tissue contact with the receptor site. Slight positive pressure from the pontic will further form the tissue. In this way, a concave pontic zone is created that will present a contour on the labial that resembles the alveolar process, gingiva, and papillae of the adjacent teeth.²⁶ The convex tissue surface of the pontic is easily cleaned with dental floss.

Ridge Preservation

Ridge preservation procedures are combined soft tissue and hard tissue grafts of extraction sockets done in conjunction with the removal of teeth. The intent of these procedures is to prevent resorption of the alveolar bone and collapse of the soft tissues, thereby reducing the need for subsequent augmentation of a deficient ridge. Extraction should be done atraumatically, preserving as much of the supporting bone and gingival tissues as possible. Thorough debridement of the socket to remove all granulation tissue is followed by cortical perforations of the socket walls to enhance the supply of osteoprogenitor cells to the graft material. An osseous graft is then packed into the socket and covered with a connective tissue graft,²⁷ tissue plug,²⁸ or barrier membrane.²⁹

Use of a connective tissue graft to seal the socket is indicated in situations where there has been a loss of soft tissue height at the free gingival margin or the papillae of the tooth to be extracted (Figure 11). After the tooth has been removed, horizontal incisions are made palatal to the col of the papillae. Split-thickness flaps are then elevated circumferentially around the extraction socket. These incisions extend into the palate far enough to allow ready elevation of the superior palatal flap and extend to the labial far enough to thoroughly mobilize the facial flap. Vertical releasing incisions are often necessary on the facial to provide an adequate degree of flap mobilization. A connective tissue graft at least 1.5 mm thick is placed to cover the osseous graft in the socket and is draped over the surrounding alveolar bone. The connective tissue graft should extend laterally far enough to cover the interproximal bone in order to coronally position and augment the papillae. The graft is placed at least 4 mm under the facial and palatal flaps to ensure adequate blood supply to the grafted tissue and to coronally position the marginal tissues. The connective tissue graft is sutured into position using periosteal sutures, the flaps are positioned to cover the graft, and the papillae are reapproximated over the graft. No attempt is made to cover the connective tissue over the orifice of the socket. The area over the socket is allowed to heal by lateral epithelial migration over the exposed connective tissue surface.

In cases where the alveolar crest is intact and the free gingival margin and papillae are in an esthetically acceptable position, the "tissue-plug" technique can be used (Figure 12). The teeth are removed as atraumatically as possible, and osseous grafts are placed in the extraction sockets. Then a tissue plug of epithelium and connective tissue is taken from the palate and placed in the orifice of the extraction socket. The tissue-plug graft must completely fill the opening of the socket and provide intimate contact with the gingival tissues to establish a blood supply to the graft. Horizontal mattress sutures are used to hold the plugs in position. These ridge preservation techniques can also be used in cases of immediate or delayed implant placement (Figure 13).

Ridge preservation procedures require that a provisional restoration be provided to the surgeon for the day of surgery. If a fixed partial denture is planned, there are three ways to approach fabrication of the provisional prosthesis. In the first method, the abutment teeth are prepared prior to surgery and individual provisional restorations are placed on these teeth. The restorative dentist also fabricates a provisional bridge prior to the surgery. This bridge is sent to the surgeon. The individual provisional units are removed during surgery, and the provisional bridge is placed at the conclusion of the procedure. The second method is to place a provisional splint on the affected teeth prior to the day of surgery. In this technique, the teeth slated for removal, as well as the abutment teeth, are prepared to receive provisional restorations; and a provisional splint is fabricated that covers all the prepared teeth. At the end of surgery, the provisional is back-filled with acrylic or composite to form pontics where the teeth have been removed. The third method is to cut off the crowns of the teeth slated for extraction flush with the gum line at the same time the anchor teeth are prepared for the provisional bridge. When fabricating the provisional bridge, a pontic is formed over the remaining root. The root is removed during surgery, and the provisional is modified as necessary prior to recementation.

If implants are planned, an interim partial denture is usually used as the provisional restoration. The interim partial denture must be fabricated in such a way to control pressure on the surgical site and to minimize movement during function.

Three months after the ridge preservation procedure is completed, the tissues are assessed. If there is no need for further augmentation, the final prosthesis is begun four months postoperatively.

Crown Lengthening

Patients may present with an excessive or aberrant display of gingival tissues. Periodontal surgery, orthodontics, or orthognathic surgery may be required to improve the esthetics of the smile. A thorough understanding of the patient's desires as well as proper diagnosis of the case is essential for developing the correct treatment plan. Often a multidisciplinary approach including several of these techniques is the best way to treat a given clinical situation.

Periodontal crown lengthening procedures can modify the supporting apparatus of the teeth through the judicious surgical removal and reshaping of the soft tissues and/or bone. The desired result is an increase in the length of the clinical crown and a concomitant reduction of gingival exposure. This will effect an improvement in esthetics by altering the ratio of the clinical crown to the marginal tissue in favor of the teeth. Crown lengthening in the esthetic zone may be necessary in cases of altered passive eruption, vertical maxillary excess, biologic width invasion, and inconsistent free gingival margin positions.

Figure 14. Diagrammatic representation of the dentogingival complex.

Successful crown lengthening requires an understanding of the biologic width of attachment and the relationship among the alveolar crest, the position of the free gingival margin, and the tip of the papilla. On the facial of a tooth, the biologic width of the attachment between the soft tissues and the root of the tooth has been shown to average 1 mm of connective tissue attachment coronal to the alveolar crest followed by 1 mm of epithelial attachment and then a 1 mm histologic sulcus.³⁰ (This combination of connective tissue attachment, epithelial attachment, and sulcus is known as the dentogingival complex). Therefore, there is a total of 3 mm from the alveolar crest to the free gingival margin on the labial of a tooth (Figure 14). At the midfacial, the crowns of maxillary central incisors and cuspids are 11 to 13 mm long.³¹ Taking the dentogingival complex into account, there is 14 to 16 mm from the occlusal plane to the alveolar crest on these teeth. Between the teeth, the position of the interdental contact point, root proximity, and the height of the alveolar crest have been shown to affect the conformation of the interproximal tissues.^32,33 Clinically, one can expect 3 to 5 mm from the alveolar crest to the tip of the papilla. The goal of crown lengthening surgery is to reposition the dentogingival complex to a location on the tooth that is esthetically and structurally more favorable while maintaining the health of the tissues.

Figure 15A. Preoperative smile in a case of altered passive eruption. Note short squat teeth and excessive gingival display. Figure 15B. Surgical guide stent. Figure 15C. Gingivectomy incisions placed with the aid of the stent. The goal is to increase the length of the teeth and develop a symmetrical gingival margin. Note that a wide band of gingiva will remain after the gingivectomy. Figure 15D. Flap elevation leaving the papillae in place pre-osseous surgery. Figure 15E. Post-osseous surgery to establish room for the dentogingival complex and position the gingival margins. Figure 15F. One-year postoperative view illustrating the characteristics of the ideal smile created by the combination of periodontal and restorative therapy (Restoration by Dr. Michael Hack).

Periodontal crown lengthening can be accomplished in several ways: gingivectomy, apically positioned flaps, osseous surgery, or a combination of these techniques. A gingivectomy is appropriate when a wide band of gingiva is present (enough to leave at least 4 mm of gingiva after the gingivectomy) and when the bony crest is at least 3 mm apical to the desired position of the free gingival margin. This 3 mm is necessary so there will be adequate room on the root for the re-formation of the biologic width of attachment and a sulcus. The apically positioned flap is used when there is at least 3 mm between the alveolar crest and the desired position of the free gingival margin, but the entire band of gingiva must be preserved and moved apically. Osseous surgery is used with a gingivectomy or apically positioned flap when it is necessary to remove bone to establish 3 mm between the alveolar crest and the desired position of the free gingival margin.

In a case with adequate gingiva, the first step in surgical crown lengthening is a gingivectomy to establish the proper free gingival margin relationship (Figure 15). Once the free gingival margin position has been established, the operator can sound to the alveolar crest to determine if there is adequate distance (3 mm) to the osseous crest for the dentogingival complex. If there is less than 3 mm, then flaps need to be elevated and bone must be removed to re-establish the 3 mm distance between the bone and the free gingival margin. This will ensure long-term stability of the surgical results. In a case that lacks adequate gingiva, the gingiva must be augmented prior to, or in conjunction with, the crown lengthening surgery.

Less than ideal results will be produced if a gingivectomy is used as the sole method of crown lengthening in a situation that requires the removal of bone to establish 3 mm between the desired position of the free gingival margin and the alveolar crest. If bone is not removed, the soft tissue will rebound postoperatively to re-establish the proper dimension for the dentogingival complex. Therefore, the results of this inappropriately done crown lengthening will be short-lived, and the final free gingival margin position will be too far coronal on the tooth.

The restorative dentist can fabricate an acrylic or composite surgical guide stent that clips over the teeth and partially covers the gingiva (Figure 15B). This stent will aid the surgeon with the placement of incisions and the removal of bone.³⁴ The guide stent can also act as a preview device, giving the patient and doctors an opportunity to assess the proposed length of the teeth prior to beginning therapy. Before surgery, the stent is modified as necessary to satisfy the patient’s esthetic desires. The stent is used by the surgeon as a template to locate precisely the position of the free gingival margin.

When crown lengthening is necessary only on the labial, a facial full thickness flap is reflected, leaving the interproximal soft tissues and the full height of the papillae in place. Then, ostectomy is performed to create the space for the dentogingival complex. The flap is then positioned and sutured in place. When circumferential crown lengthening is necessary, the flaps need to preserve the height and volume of the interproximal papillae and still provide 360-degree access to the supporting bone for ostectomy. The papillae are incised and elevated intact as part of the facial flap,³⁵ the ostectomy is performed, and then the papillae are repositioned and sutured.

If an intracrevicular margin is planned, the restorative dentist should wait until maturation of the attachment and stability of the gingival crevice prior to the final restoration of the case. The time to full tissue maturity varies among procedures and patients. Postoperative tissue stability can only be ensured by two consistent measurements of sulcus depth and free gingival margin position over time. The interval between these measurements should be at least six weeks.

Figure 16. The intracrevicular restorative margin. When the margins of restorations are placed apical to the free gingival margin, they should never invaded the biologic width of attachment but should reside in the sulcus. The circumferential architecture of the soft tissues dictates proper margin placement (JE -- junctional epithelium; CTA -- connective tissue attachment) .

Adequate sulcus depth for intracrevicular restorative dentistry may not develop for six months or longer after surgery³⁶ (Figure 16).

Summary

As the demand for esthetic dental procedures has increased, the dental field has responded with improved techniques and materials to address this demand. Periodontal plastic surgery can support the efforts of the restorative dentist by providing a healthy and esthetic dentogingival complex. The scope of periodontal plastic surgery procedures has been outlined to aid the dental team in the proper diagnosis and multidisciplinary treatment of the esthetic dental case.

References/

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