Aesthetic Buccal Flap Design for Correction of Buccal Fenestration Defects
Marius Steigmann, DDS
In contrast to the focus on successful osseointegration that characterized the early years of implant dentistry, contemporary practitioners are primarily concerned with achieving the most natural-looking smile possible through implant placement procedures that preserve the anatomy of the soft tissue.1-8 When a single tooth is compromised and the gingiva and surrounding osseous structures remain healthy, flapless surgery with immediate implant placement provides an excellent means by which to maintain the natural soft tissue contours.9-13 However, when the development of an apical fenestration compromises the soft tissue and surrounding osseous structures, the creation of a full mucoperiosteal flap is required, and the subsequent healing of the soft tissue can have negative impacts on the aesthetic outcome.
When the soft tissue presents no sign of recession, and only limited interproximal resorption of the bone has occurred, an aesthetic buccal flap (ABF) may be utilized to correct buccal apical fenestration while maintaining the overall aesthetic appearance. This technique employs guided bone regeneration (GBR) to preserve the natural supraosseous soft tissue profile.
The ABF technique presented here is appropriate for single-tooth applications or when no more than two adjoining teeth require augmentation, as the creation of larger flaps poses too large a risk of necrosis. Furthermore, this technique is appropriate only for correcting apical buccal defects and is only applicable when the supporting interproximal crest has not undergone significant osseous resorption.
The ABF Technique
The intended tooth must support the horizontal incision that is created in the keratinized gingiva, approximately 1 mm to 2 mm coronally from the mucogingival junction. Creation of the ABF, therefore, must precede tooth extraction to minimize postsurgical scarring. Once the initial incision is complete, two vertically beveled releasing incisions are made, extending into the mucosa. These incisions should be positioned far enough apart to adequately cover any bone-grafting material placed below the flap (Figure 1). The tooth extraction is performed and the ideal implant position is confirmed. A minimum of 4 mm of bone apical to the sulcus is necessary to achieve primary stability for an immediately placed implant.14 Optimally, the implant should be positioned slightly more palatally than the original tooth, in order to avoid buccal plate resorption. Following a thorough cleaning of the extraction socket with curettes and rotation instruments, an osteotomy is created following the suggested protocol of the implant manufacturer. Undersizing the osteotomy may improve primary stability, particularly in soft bone. The implant is then placed, and instruments are used to torque it to final position relative to the vertical and horizontal dimensions of the interproximal bone (Figure 2).15 Once the implant has been placed, bone deficiencies may be corrected using a combination of bone-augmentation material and a collagen membrane (Figure 3).16 Prior to flap closure, a temporary abutment is connected to the implant. Following cementation of the provisional restoration, the flap must be sutured. Any tension on the remaining attached gingiva may lead to future recession of the buccal soft tissue. To avoid this, the apical portion of the flap is slightly released once the bone-grafting materials have been positioned. The flap is repositioned and, using 5-0 suture material, the vertical incisions are sutured in their original position. The horizontal incision is then closed in a tension-free position (Figure 4).
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A 25-year-old female with presented with obvious gingival scarring as a result of previous apicoectomies and inflammation of the soft tissue above the left central incisor (Figure 5). Radiographic examination confirmed the presence of an acute infection, with bone resorption limited to the area of the root perforation (Figure 6). Adequate interproximal bone height was evident, and a decision was made to extract the incisor and place an implant immediately in the extraction site, while simultaneously repairing the buccal plate via an ABF. The ABF was created by a 5-mm horizontal incision made approximately 1 mm coronally from the mucogingival junction (Figure 7), followed by two 8-mm to 10-mm vertical incisions. Elevation of the ABF revealed the absence of the buccal plate, with granulation tissue growing into the defect (Figure 8). The horizontal incision was supported by the tooth, with only a thin bridge of buccal bone remaining apically. The soft tissue bridge also remained intact, an important prerequisite to preserving optimal aesthetic contours (Figure 9). The tooth was extracted and a probe was used to help determine proper implant size and where it should be positioned. Following implant selection, a surgical guide was positioned, and a 2.3-mm pilot drill was used to create the osteotomy (Figure 10). A parallel pin was placed to confirm that the implant was ideally positioned at the connection line of the two incisal edges (Figure 11). The osteotomy was not created exactly where the tooth was located, but rather more palatally in order to avoid resorption of the buccal plate.
Approximately two thirds of the extracted tooth’s root tip was removed, taking care to ensure that enough of the tooth was retained to adequately support the soft tissue during provisionalization.
A 12-mm-long, 2.7mm-diameter implant was placed (Figure 12). The fixture mount was removed, and an acrylic prosthetic abutment was connected to the implant. The provisional tooth was positioned and modifications to the tooth and the abutment were made as necessary.
With the tooth in final position on the abutment, grafting material was placed around the implant and covered with a bovine pericardium membrane (Figure 13).17 The author has found that using autogenous bone on the screw helps to promote optimal implant osseointegration, while an additional layer of bovine bone creates valuable space.16 A periosteal releasing incision was made, and the flap was repositioned. Microsutures were used to secure it, starting from the most apical point on both of the vertical segments and alternating between the left and right sides, in order to balance the tension between them. Suturing in this manner allowed the horizontal incision to be approximated without any tension whatsoever. The presence of such tension can cause the soft tissue to recede. Once the flap was completely sutured, the provisional tooth was placed using temporary cement (Figure 14). The patient was advised to avoid applying any undue force on the tooth for the first few months; a soft diet was not required in this case. Sutures were removed two weeks postoperatively. This patient returned one year later for placement of the definitive prosthesis. At that point, the plastic prosthetic abutment was replaced with a titanium abutment and the definitive porcelain-fused-to-metal prosthesis was delivered (Figures 15 and 16).
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A 35-year-old male patient presented with a traumatic injury and root fracture in tooth #9(21) following a motorcycle accident. Prior to extraction, incisions were made to create an ABF (Figure 17). Although the coronal section of the root was removed during tooth extraction, the apical section remained in the maxilla and required removal (Figure 18). An implant was immediately placed into the extraction socket and guided bone regeneration was performed using autogenous bone, bovine mineral, and a pericardium membrane (Figure 19). In order to maintain the soft tissue contour, the natural tooth was repositioned following implant placement and suturing of the ABF (Figure 20). Radiographic and clinical evaluations at six months and one year demonstrated satisfactory stability and a healthy gingival margin (Figures 21 and 22).
Placing implants where optimal bone anchorage is available often precludes achievement of the desired prosthetic results. When implants are placed according to prosthetically driven guidelines as opposed to bone-driven principles, however, fenestrations in the apical areas of the implant may be inevitable. Although GBR techniques can readily correct such defects, they require access to the defects via buccal flap elevation. While the classic flap approach may result in a compromised aesthetics, the ABF presented in this article avoids this potential.
The ABF design is particularly beneficial in aesthetically sensitive areas (eg, the maxillary anterior region). In order to maintain a natural-looking result, the soft-tissue housing must be preserved. This technique allows a clinician to ensure soft tissue aesthetics, even when localized bone deficiencies have developed prior to or during implant-placement surgery.
*Adjunct Assistant Professor of Oral and Maxillofacial Surgery, Boston University, Boston, Massachusetts; private practice, Heidelberg, Germany.
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