Clinical dental advantages of the apically positioned flap
The apically positioned flap is a commonly used surgical approach to achieve pocket elimination. This technique is important for maintaining an adequate zone of keratinized tissue, as opposed to the gingivectomy technique, where soft tissue is resected.
ADDITIONAL READING |Attached gingiva and dental implants
Indications for the apically positioned flap include 1. surgical crown lengthening procedures, and 2. the treatment of periodontal disease where preserving the maximum amount of keratinized gingiva is the desired outcome. The contraindications for the apically positioned flap include root hypersensitivity, high rate of root caries, esthetic limitations, anatomic limitations, inadequate clinical attachment, and deep infrabony defects.
1. Clinical crown lengthening is a surgical procedure to increase the amount of exposed tooth structure. There are two main types of crown lengthening: functional and esthetic. Functional crown lengthening may be performed to expose subgingival caries, a fracture, or both. Garguillo et al. described a concept known as “biologic width,” which consisted of a connective tissue attachment of 1.07 mm and the average epithelial attachment was 0.97 mm, forming an average biologic width of 2.04 mm. Rosenberg et al. furthered this concept and combined the average biologic width of 2.04 mm with the 1 mm to 2 mm essential for restorative dentistry, concluding that 3.5 mm to 4 mm of sound supraosseous crest tooth structure is needed to fulfill the total requirement for restorative dentistry. The indications for crown lengthening surgery include caries, fracture, altered passive eruption, root surface preparations, and restorative requirements. (Figs. 1 and 2) The apically positioned flap offers several advantages over the gingivectomy technique for surgical crown-lengthening procedures. These include maximizing the postoperative keratinized attached tissue, increased access to the alveolar bone, faster and more comfortable wound healing, and more predictable placement of the margin of gingiva.
Fig. 1: Clinical image prior to crown lengthening for preparation for restoration
Fig. 2: Post crown lengthening image after temporization 2. When treating periodontal disease, (Fig. 3) the apically repositioned flap technique involves a reverse beveled incision with a scalpel. The distance from the tooth, buccally or lingually, is dependent on the pocket depth, and the beveled incision should be scalloped to maximize the amount of interproximal alveolar bone that will be covered after the flap is positioned apically. The original technique also involves vertical releases at the mesial and distal extent of the flap, extending beyond the mucco-gingival junction, to facilitate the apical positioning of the flap. Next, a full thickness mucco-periosteal flap, including the alveolar mucosa and the keratinized tissue, is raised both buccally and lingually beyond the mucco-gingival junction. (Fig. 4) If the flap is not raised beyond the mucco-gingival junction, then it would be impossible to advance the flap in an apical direction. After the full thickness mucco-periosteal flap is elevated, then the collar of soft tissue is removed from around the necks of the teeth with surgical curettes. This marginal collar of soft tissue includes diseased epithelial soft tissue and granulation tissue. After the surgical area is degranulated, the roots of the teeth are meticulously scaled and root planed.
Fig. 3: Clinical image of a patient with severe periodontal disease
Fig. 4: Mucoperiosteal flap beyond mucogingival junction and surgical debridement
Once the physiologic alveolar bone contour is achieved, the flap is apically advanced to the alveolar bone crest and secured with sutures. (Fig. 5) Since it is not always possible to completely cover the entire alveolar bone complex with soft tissue, some areas of alveolar bone may be left denuded. After the surgical site has healed, the technique should preserve the zone of keratinized soft tissue and yield shallow probing depths. (Fig 6)
Fig. 5: Apically repositioned flap and suture
Fig. 6: Gingival tissues and bone levels remain stable 2½ years after surgical therapy
Photos courtesy of Scott Froum, DDS
References
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