The palatal straight advancement flap is of limited use due to the inelastic nature of the palatal tissue, which reduces its lateral mobility. For the same reason, it is suitable for the closure of minor palatal or alveolar defects [17].

The palatal hinged flap has been used successfully to close small fistula of the hard palate, i.e., those less than 2 cm in diameter in a one-stage operation [18]. The procedure is based on raising a full-thickness flap directly adjacent to the fistula based along one fistula edge and turning this like a hinge over the fistula so that its buccal surface will lie uppermost in the fistula. The main advantage of this technique is that only a small raw area for granulation is left behind following closure of OAF.

Another single-stage local flap is the palatal pedicled island flap. It offers the great advantages of a rich vascular supply, adequate bulk, and mobility. In elevating the flap, incisions are performed according to the amount of donor tissue required to resurface the oral fistula. Incisions can be made at the junction of the hard and soft palate and within 5 mm of the dentition. This allows for harvesting a flap that can be rotated 180° without strangulation of the vascular pedicle. This procedure is the preferred flap for many surgeons because of its versatility, simplicity, and mobility [19]. The technique is ideal for the closure of posterior fistula due to its ability to transfer large well-vascularized area of tissue. Furthermore, the donor site defect, which overlies the hard palate, decreases the donor site morbidity. Therefore, use of this procedure is limited in closure of anterior defect as a result of stretching of these vessels when the flap is advanced too far anteriorly. The palatal anteriorly based flap is particularly useful for closure of large oroantral fistula and correction of defects at the tuberosity region. The procedure involves a lateral transposition of mucoperiosteum of the posterior third of the hard palate with an anteriorly based palatal flap. The flap is raised to bridge large defects without leaving any considerable exposed raw area [20]. The modified submucosal connective tissue flap was designed by Dergin et al. [21] for closure of OAF. Elasticity of the flap prevents folding formation and allows for better manipulation and adaptation in the closure of an OAF in the second and third molar region. Another advantage is that no palatal acrylic plate is required postoperatively. In this technique, an H-type window-like incision is made in the palatal mucosa 4 mm from the gingival margins of the posterior teeth, with the medial incision 2–3 mm from the midline. After excising the fistula wall and curetting the granulation tissue, the mucosa of the two minor flaps of the H-type window-like incision is raised and separated from the underlying connective tissue without jeopardizing the continuity of the mucosal flap. The underlying vascularized connective tissue is dissected in the premolar-canine region, where the incisive and greater palatine arteries anastomose. The connective tissue is raised with periosteum and rotated. The rotated flap is passed through a full-thickness tissue tunnel that had been previously prepared on the palatal side of the OAF. The flap is inserted under the buccal mucosa and sutured without any tension. The H-type minor flap is also sutured and left for primary healing. Hara and Ito designed the submucosal connective tissue pedicle flap by dividing the flap into an upper mucosal layer and underlying connective tissue layer to overcome the problem of bone exposure at the donor site [22]. The technique is achieved by separating the full-thickness palatal flap into a mucosal layer and an underlying connective tissue layer. The submucosal connective tissue flap is used to close the fistula, and the mucosal part of this flap is then returned to its original position and sutured in place to obtain primary closure. They reported that the healing at the donor site occurred within 1 month [22]. The disadvantages of this technique are the difficulty of the dissection and possibility of injuring the blood supply [22]. A submucosal island flap is indicated in the closure of a large oroantral fistula. With this technique, a palatal pedicle flap based on the greater palatine vessels is formed. Depending on the size, shape, and location of the fistula, the anterior part of the submucosal connective tissue flap is made. In addition, the anterior part of the submucosal connective tissue is used to design the island flap. After raising the palatal mucoperiosteum, the island flap is passed under the alveolar tissue bridge across the defect and sutured to the edge of the fistula without tension. The significant advantages of this flap are ample blood supply and mobility without tissue bunching [23]. In addition, healing is satisfactory without denuded bone. Yamazaki concluded that the dissection of the palatal flap into the epithelial layer and the underlying connective tissue does not pose technical difficulty [23]. A palatal pedicle flap is used to close an OAF with the advantages of preserving keratinized mucosa and buccal sulcus depth in the area of the fistula. The flap is a one-stage procedure. Preoperative procedure includes making a self-curing acrylic resin plate over the patient’s cast model. The first surgical step is excision of the epithelial fistula wall, followed by division of the flap on the palatal mucosa through an incision, superficially to the periosteum. The flap is passively positioned and thoroughly sutured. The donor site is then protected with surgical cement and held in place by the self-curing acrylic resin plate. The acrylic plate is fixed with bone screws and maintained in place for 10 days [24]. The ratio of length to thickness of the flap is critical for the survival of the palatal pedicle flap, thus splitting of the flap should be carried out very judiciously [24]. The Random palatal flap is considered an adequate option for closure of oroantral fistula in difficult locations such as in the tuberosity area. Lee et al. reported a success rate of 76% of random palatal flaps in 21 patients [25]. He pointed out that the most important factor determining the clinical outcome of palatal flaps was an appropriate length to width ratio. The random palatal flap is based on the anastomoses spread throughout the palate; all rely on greater palatine artery for nutrition. The buccal fat pad (BFP) is a lobulated mass of adipose tissue surrounded by a thin fibrous capsule, located between the buccinator muscle medially, the anterior margin of the masseter muscle, and the mandibular ramus and zygomatic arch laterally [26]. The buccal pad of fat is exposed through a 1 cm long vertical incision in the reflected periosteum posterior to the zygomatic buttress. Thereafter, it is gently manipulated by pressing extraorally below the zygomatic arc. Finally, the fat pad is sutured to the palatal tissue, covering the oroantral fistula [27]. The BFP derives its blood supply from branches of the superficial temporal, maxillary, and facial arteries. The advantages of this technique include good epithelialization of the uncovered fat and a high rate of success due to the BFP’s ample vascularity and proximity to the recipient site. Other beneficial features of the BFP flap are the straightforward harvest and minimal dissection required to harvest and to mobilize the flap [28]. The study of the long-term effectiveness of the BFP technique in the closure of large OAFs supported these features [29]. The disadvantage is the decrease in the vestibular height. It has been concluded that closure of large defects could involve complications such as graft necrosis or new fistulas [30]. The buccal fat pad is a feasible option for cases with damage to the alveolar buccal or palatal mucoperiosteum, cases that have failed with other methods, and repairs of large defects in the tuberosity area [31]. However, success of the buccal fat pad is extremely influenced by the communication size [32].