Report of an Intra-antral calcification following a buccal fat pad Obturation: A 4-year follow-up.

Introduction

The enucleation of cysts in the posterior maxilla can be subject to many complications including extensive bone loss, fracture of the maxillary tuberosity and sinus perforation [1]. In such cases, the oral surgeon might use various substitutes in order to fill and restore these defects such as the buccal fat pad [2].

The buccal fat pad, also known as Bichat’s fat pad, is an adipose mass of the maxillofacial skeleton located in the cheek at the middle third of the face facing the posterior maxilla with a buccal, temporal, pterygoid and pterygomaxillary extensions [3]. Anatomically, this structure is divided into three independent encapsulated lobes: the anterior, intermediate and posterior, which are anchored to their surrounding tissues through ligaments and nourished by a complex capillary network [3].

The anterior lobe of the buccal fat pad has a triangular shape and is located within the cheek below the zygoma and in front of the buccinator muscle [3]. It is mainly vascularized by the posterior superior alveolar artery along with the buccal artery and drained through the facial vein [3]. The superficial anatomical position of the anterior lobe makes it easily reachable by making a deep vestibular incision in the posterior maxilla region [3]. It is often used by the oral surgeon for the closure of oro-antral fistulas, and large defects fill after a tumor resection and to cover zygomatic implants or bone grafts [4].

Recently, several studies investigated the osteogenic properties of the buccal fat pad by engineering a mimetic scaffold seeded with buccal pad fat cells to promote bone regeneration in maxillofacial defects [5]. However, few studies or reports elucidated the behavior of the fat pad when placed in a cystic cavity or in an intimate contact with the sinus membrane [6].

The presented case is a description of a rare finding regarding the outcome of using the buccal fat pad as a grafting material to restore a large defect caused by the enucleation of a dental cyst located in the maxillary sinus.

Case Presentation

A 25-year-old female patient, systemically healthy, was referred to the oral surgeon F.R after a displacement of the left upper third molar into the sinus during the tooth extraction.

The clinical examination showed a feeling of discomfort by the patient to the palpation of the left cheek with moderate pain. Intraorally, a suppurative third molar socket was detected with the tooth unapparent and no sign of oro-antral communication. As for the radiographic examination, little evidence could be retrieved from the panoramic X-ray (Fig. 1a); therefore, it was followed by a cone beam computed tomography (CBCT) scan. The resulting three-dimensional images showed the third molar floating inside a large cyst occupying most of the sinus area (Fig. 1b).

Fig. 1.

Preoperative radiologic examinations, a panoramic image showing the maxillary left third molar displaced in the sinus. b Cone beam computed tomography image of the left maxilla. Left: frontal view showing the cyst occupying the totality of the sinus. Right: cross-sectional view showing the sinus breach and the caudal limits of the cyst

The critical location of the displaced tooth and the large cyst made the conventional surgical treatment under local anesthesia unfeasible. Therefore, cyst enucleation under general anesthesia was planned. The patient was given all the information about the surgical procedure and its possible complications prior to the surgical intervention. A root canal treatment was done on the first and second left molars due to a probable rupture of the superior posterior artery that nourishes these teeth.

On the surgery day, an intrasulcular buccal incision followed by two vertical oblique releasing incisions was done using a no.15 blade (Fig. 2a). The trapezoidal mucoperiosteal flap was then reflected from the alveolar crest with its limits extending from the maxillary tuberosity to the canine. Careful osteotomy of the sinus buccal wall extending from the distal of the second premolar to the second molar, 3 mm from the alveolar crest, was done using surgical burs, and a wide access to the sinus cavity was granted without the perforation of the sinus membrane as performed during a conventional lateral sinus lift (Fig. 2b). Last, the cyst volume was reduced by the aspiration of its yellowish suppurative content using a 5-ml syringe (Fig. 2c) before being completely enucleated with the third molar which were both located distally to the membrane using Freer periosteal elevator with minor damage to the sinus membrane (Fig. 2d). Minimal sinus perforation was seen at different spots especially at the cyst attachment.

Fig. 2.

Clinical images of the cyst enucleation: a incision design, b cystic membrane in the sinus, c cystic liquid content, d excised cyst and tooth, e bone defect following the cyst enucleation, f suture of the buccal fat pad, g suture of the mucoperiosteal flap over the fat pad

A large bone defect was now clearly observed which had to be filled in order to prevent any blood clot infection and to restore the lost bone (Fig. 2e). Therefore, the buccal fat pad was exposed using an incision in the buccal vestibule of the maxillary molars, then drawn out and draped into the cystic cavity with a straight hemostat Kelly plier (Fig. 2f) to be finally covered by the mucoperiosteal flap and sutured using intra-bony 4/0 resorbable polyglycolic acid sutures (Fig. 4G). The enucleated cyst was fixed with 4% formaldehyde and sent for a histopathological examination which confirmed its dentigerous nature; therefore, no additional measures were taken.

The wound healed uneventfully, and the patient’s normal sinus and maxillary function were restored. One year later, during a consultation for a rhinoplasty, CBCT examination showed a large calcification within the treated maxillary sinus (Fig. 3). The endoscopy examination showed no closure of the sinus meatuses. The patient was asymptomatic, and based on her demand, no treatment was performed, and a yearly follow-up was suggested by the physician to monitor the growth of the calcified mass.

Fig. 3.

Postoperative cone beam computed tomography images showing the calcification in the maxillary sinus

After 4 years of follow-up, the patient was still asymptomatic and showed no dysfunctional sign in the ENT region, and thus, no additional surgeries were undertaken.

The patient signed an informed consent allowing the authors to publish the clinical and radiological findings.

Discussion

The buccal fat pad is an adipose tissue regarded as a versatile solution for many posterior maxilla defects treatment [7]. It is composed mainly of fat cells and pluripotent mesenchymal cells that have an osteogenic differentiation potential when placed in specific settings [5]. It also has an epithelialization potential mainly seen when it is left exposed in the oral cavity [7].

Many studies have demonstrated the utility of the buccal fat pad in bone regeneration by evaluating the potential osteogenic differentiation of its mesenchymal and fat cells used together or solely on engineered scaffolds [5]. Otherwise, the sinus membrane also contains pluripotent mesenchymal cells with the ability to promote bone formation following a sinus grafting procedure [8]. In consequence, the probable theory that explains the observed outcome might be an interaction between the buccal fat pad and the sinus membrane which created a favorable environment for the osteogenic differentiation of the mesenchymal cells and the formation of large calcified mass in the sinus cavity [6]. At the third year of follow-up, a corticalization at the peripheries of the fat mass was seen indicating the end of the calcification extent.

Despite the lack of evidence in the literature, such rare observations might shed some light on the use of the buccal fat pad as a graft material in the maxillary sinus. For that, a reassessment and a profound assumption of the biological process of this technique is a must.

Certainly, calcified tissues in the sinus known as “antrolith” could be a direct cause for chronic sinusitis, especially in ill ventilated sinuses. Despite the asymptomatic status of the observed patient, one should always carefully interpret such observations and relate them to a possible respiratory dysfunction and therefore perform an antrostomy in conjunction with the removal of the calcification to relive the patient’s symptoms.

A possible improvement of this technique could be the use of a collagen fleece with antibiotic particles which appears to be helpful in stabilizing the blood clot and preventing infections [9]. Also, it is better to withdraw the bone in one block while gaining access to the sinus cavity in order to use it later at the end of the surgery as a seal of the sinus cavity [10]. Despite these promising treatment options, the findings in the literature are very limited leaving little scientific support for an ideal treatment modality. Further clinical trials are required in order to establish an appropriate evidence-based technique for such complicated situations.