▋ Patient Overview
This case presents another patient with cleft lip and palate who underwent maxillary occlusal reconstruction using zygomatic implants. In addition to severe maxillary bone deficiency, a notable finding during intraoral examination was a communication between the right maxillary buccal vestibule and the nasal cavity, a condition known as an oronasal fistula.

The patient experienced leakage of liquids from the oral cavity into the nasal cavity during eating, leading to difficulty in food intake and a risk of inflammation and infection. However, because the patient routinely wore a removable denture, the flange of the denture effectively covered the oronasal fistula, and the patient reported no usual issues with fluid leakage into the right nasal cavity.

▋ Surgical Plan
The patient had previously undergone cleft lip repair using an Abbe flap (lower lip–to–upper lip flap), resulting in limited mouth opening. This oral condition posed a significant challenge for conventional bone grafting procedures for implant placement and made intraoral zygomatic implant surgery more difficult compared to typical cases.

During surgery, four zygomatic implants were placed in the preoperatively planned positions in the maxilla, along with four implants placed in the mandible.

To reduce the risk of postoperative inflammation and infection associated with the oronasal fistula and the difficulty of oral hygiene, we performed simultaneous repair of the nasal floor and oral mucosa. Additionally, a buccal fat pad was used for reinforcement. After surgery, the oronasal fistula was no longer visible, and the patient was immediately fitted with a fixed prosthesis.

▋ Conclusion
Compared to the more commonly encountered oroantral fistula in clinical practice, an oronasal fistula generally has a less immediate impact on implant outcomes. Oronasal fistulas are typically seen in patients with congenital cleft lip and palate, whereas oroantral fistulas commonly occur after tooth extraction, implant surgery, or sinus augmentation procedures that create a communication between the oral cavity and the maxillary sinus. Such pathways allow food debris and bacteria to enter the sinus, potentially leading to sinusitis and secondary implant infections.

Although an oronasal fistula does not exert as direct an effect as an oroantral fistula, in cases where patients receive full-arch fixed implant-supported prostheses, long-term hygiene may be compromised. Unlike removable dentures, fixed prostheses cannot be easily removed for cleaning, increasing the risk of infection and subsequent complications. Therefore, when performing full-arch implant rehabilitation in such patients, simultaneous repair of the oronasal fistula should be considered to reduce the risk of long-term infection.