Journal of Dental Implant Research 2023; 42(4): 67-71
Postoperative challenges in pedicled buccal fat pad grafts: MRI evaluation and the role of bone grafting for maxillary wall regeneration
Hoi-Bin Jeong , Jeong-Kui Ku
Department of Oral and Maxillofacial Surgery, School of Dentistry and Institute of Oral Bioscience, Research Institute of Clinical Medicine of Jeonbuk National University-Biomedical Research Institute of Jeonbuk National University Hospital, Jeonbuk National University, Jeonju, Korea
Correspondence to: Jeong-Kui Ku,
Department of Oral and Maxillofacial Surgery, School of Dentistry and Institute of Oral Bioscience, Research Institute of Clinical Medicine of Jeonbuk National University-Biomedical Research Institute of Jeonbuk National University Hospital, Jeonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju 54907, Korea. Tel: +82-63-250-2113, Fax: +82-63-250-2089, E-mail:
Received: November 12, 2023; Revised: November 23, 2023; Accepted: November 25, 2023; Published online: December 30, 2023.
© The Korean Academy of Implant Dentistry. All rights reserved.

This is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
This report describes a case of postoperative complications following closure of a large oroantral fistula with a pedicled buccal fat pad (PBFP). The patient initially presented with a displaced tooth within the maxillary sinus and underwent surgical removal of a maxillary cyst with fistula closure using a PBFP. However, symptoms recurred 20 months later, and MRI revealed a bone defect and a connection between the maxillary Schneiderian membrane and buccal soft tissue, including the buccinator muscle. Bio-BMP2 grafting performed to regenerate the maxillary sinus wall during an exploratory operation resolved symptoms. The study underscores the importance of reconstructing the maxillary bone to separate buccal soft tissue from the Schneiderian membrane, particularly in cases of extensive defects.
Keywords: Bone graft, Oroantral fistula, Pedicled buccal fat pad, Maxillary sinus, MRI, Postoperative complications

Dentigerous cysts develop alongside the crown of unerupted teeth1), and the majority of dentigerous cysts appear in the mandible (70%), with around 30% occurring in the maxilla2). In cases where they develop in the maxilla, these growths can expand rapidly and potentially occupy the entire maxillary sinus due to the lower bone density in the maxilla and the presence of anatomical features like the maxillary sinus3). Consequently, a large cyst can erode the wall of the maxillary sinus and intrude into its interior. Hence, the removal of sizable maxillary cysts can lead to complications such as the formation of a fistula between the maxillary sinus and the oral cavity.

The development of an oroantral fistula linking the maxillary sinus and the oral cavity triggers inflammation of the sinus membrane, leading to the accumulation of sinus secretions and resulting in maxillary sinusitis4). Symptoms of an oroantral fistula encompass pain, an unpleasant taste, and the flow of fluid from the nose into the mouth5). While smaller fistulas (<5 mm) could be healed itself, those exceeding 5 mm in diameter invariably necessitate surgical closure4). A variety of surgical techniques exist for sealing the oroantral fistula, broadly categorized into autogenous grafts (utilizing either soft tissue or bone), xenografts, and allogeneic materials6). Autogenous grafts encompass procedures such as buccal flaps, palatal flaps, and the use of pedicled buccal fat pad grafts employing soft tissue, as well as methods employing autogenous bone. Xenografts involve the application of collagen hemostats or bone graft materials, while allogeneic materials comprise allogeneic bone grafts and fibrin glue7).

Pedicled buccal fat pad (PBFP) grafts are predominantly employed for fistula closure due to their speed, safety, and simplicity. Additionally, they offer the advantage of easy maneuverability owing to their proximity to the posterior region of the maxilla and their robust blood supply8). The pedicled buccal fat pad has been shown to be effective in successfully closing the oroantral fistula9,10). Nonetheless, fistula closure with PBFP could not regenerate the sinus wall does, which has potential risk for adhesion between the Schneiderian membrane and soft tissue such as buccinator muscle. The purpose of this report is to present a patient with postoperative complications following oroantral fistula closure with PBFP, and address his symptoms with bone graft for regeneration of sinus wall.


During the initial visit, the patient presented with a displaced tooth within the maxillary sinus and a loss of the maxillary sinus floor as seen in a panoramic radiograph (Fig. 1A). Three months later, surgical removal of the maxillary cyst was performed under general anesthesia. The procedure involved making an incision in the buccal gingiva at the #14∼17 region, followed by raising a flap. The cyst within the maxillary sinus was excised, and the oroantral fistula was closed using a graft of buccal fat pad, which was sutured using a buccal flap (Fig. 1B∼1D). Four months post-surgery, soft tissue healing was observed at the surgical site in a follow-up cone beam computed tomography (CBCT) scan without oroantral fistula (Fig. 1F).

Figure 1. The cyst enucleation surgery. (A) Pre-operative panoramic view showed a large cyst in the left maxillary sinus. (B) The cystic lesion was enucleated. (C) A large cystic defect with loss of maxillary wall. (D) The defect was packed with pedicled buccal fat pad. (E) Primary closure. (F) CT coronal view demonstrated insufficient bone healing after fourth month.

However, twenty months after the initial operation, the patient returned to the hospital with complaints of an unusual liquid flowing into the left nose when opening of mouth. When he opened his mouth and then closed it, he said he could feel the water sloshing around on the left side of his nose, and shortly afterward, he felt the water passing through his nose. A bone defect was identified in the apical area of tooth #17 without sinusitis (Fig. 2). The authors decided an exploratory operation to resolve his symptoms.

Figure 2. Panoramic view (A) and cone beam computed tomography (B) at twenty months after the surgery demonstrated insufficient bone healing without oroantral fistula or maxillary sinusitis.

Although there was no visual oroantral fistula (Fig. 3A), a scar tissue was identified and removed in the bony defect (Fig. 3B, 3C). The authors thought that his symptoms might be caused by continuation between the maxillary membrane and buccal soft tissue. To reconstruct the maxillary sinus wall, the defect was grafted Bio-BMP2 (Cellumed, Seoul, Korea; demineralized bone matrix (DBM) and recombinant human bone morphogenetic protein-2 (rhBMP-2)), and primary closure was achieved (Fig. 3D∼3F).

Figure 3. Revision surgery. (A) Pre-operative intraoral image without oroantral fistula. (B) Incomplete bone healing at the cystic defect. (C) Removed scar tissue in the defect. (D) Bone defect after removing scar tissue. (E) Bone graft with allogeneic demineralized bone matrix with rhBMP-2. (F) Primary closure.

Following the reoperation, his sinus-related symptoms were all subsided without any complications. The postoperative images were taken five months after the surgery. In CBCT, the grafted bone regenerated into the maxilla to allow separation between the maxillary sinus membrane and buccal soft tissue (Fig. 4). In MRI, the buccinator muscle, adhered into the soft tissue in the defect pre-operative image, was attached the regenerated maxillary bone (Fig. 4).

Figure 4. Pre-operative (A, B) and post-operative image (C, D) of the revision surgery. T2-weighted MRI showed that the location of grafted pedicled buccal fat pad (white triangle) was similar after the surgery. However, the buccinator muscle (white arrow) was adhered to the scar tissue and the fat pad before surgery. After the bone graft, the muscle was attached on the regenerated maxillary bone.

During the first surgery, his maxillary wall was packed with buccal fat pad to prevent an oroantral fistula. Although this primary purpose was achieved, his maxillary wall was not regenerated during about two years. As a results, his buccinator muscle was adhered to the scar tissue connected with the maxillary Schneiderian membrane (Fig. 4). The muscle became separated from the Schneide-rian membrane through the bone graft at the second revision surgery, and his symptoms was addressed. With regarding his pre-operative CBCT, a sinusitis or oroantral fistula was not evident, his symptoms might be due to the fact that the buccinator muscle was not attached to the maxilla. Therefore, the authors emphasize the need for reconstruction of maxillary bone to separate buccal soft tissue from the Schneiderian membrane.

Since the oroantral fistula cause unpleasant symptoms and complaint in dental clinic, many oral and maxillofacial surgeons were focused on the fistula closure in various methos such as suturing, advanced flap, and pedicled flap11). The buccal fat pad receives its blood supply from the branches of the superficial temporal, maxillary, and facial arteries. According to Parvini P et al, buccal fat pad graft has the advantage of good epithelialization of the exposed fat, sufficient blood supply and proximity to the recipient site5). In addition, according to Yang et al., this flap was easy to collect, and showed a high success rate for the fistula closure12). However, the buccal fat pad has several limitation including insufficient bone healing, recurrence of the fistula13,14). In addition, Hariram et al. compared the bone formation of a sandwich graft using hydroxyapatite crystals and collagen membrane and a buccal fat pad graft. At the 3- and 6-week intervals, the buccal fat pad graft groups reported 0% bone formation at both intervals15). Therefore, in this patient with a large maxillary defect, the PBFP alone was not sufficient to address his symptoms for a long-time. In the case of such a large bone defect, better bone healing can be induced if the fistula is closed with bone graft rather than closed with a fat pad alone. This indicated that a collagen membrane or bone grafting may be necessary on the wall defect during the sinus lateral approach among implant surgeries beyond increasing percentage of new bone formation and preventing proliferation of soft tissue16). However, these symptoms like this patient could be underestimated for the oral surgeons since they might not have any symptoms of oroantral fistula or maxillary sinusitis. To confirm the criteria for bone grafting in cases of large maxillary defects, further studies with a larger number of patients are necessary.

In the second surgery, Bio-BMP2, a mixture of rhBMP-2 and DBM, tilized as a bone graft material to close maxillary sinus wall defects. Numerous previous studies have demonstrated the outstanding osteoinduc-tive properties of rhBMP-217). DBM has been suggested as one of potential carrier of rhBMP-218-20). Although DBM/rhBMP-2 has been considered an effective graft material for bone formation in the maxillary sinus, it seems essential to conduct comparative studies with autogenous bone or other bone graft materials. This is necessary to determine a more effective bone graft material and carrier for rhBMP-2 in addressing maxillary sinus wall defects.


In the extensive defect area of the maxilla, reconstruc-tion with connective tissue using the buccal fat pad and regenerating the maxilla through bone grafting can prevent long-term complications.

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