A total of five patients diagnosed with unilateral chronic maxillary sinusitis following dental implant surgery were studied(Table.1). All patients experienced symptoms of maxillary sinusitis, such as postnasal drip(PND), foul odor or pain in the paranasal area for more than 12 weeks following the dental procedure at the time of their initial visit. Furthermore, the Cone-beam CT(CBCT) revealed a general haziness and obstruction of the maxillary ostium in the maxillary sinus on the side where the dental treatment was performed. It was a finding of chronic maxillary sinusitis.

The causative implant or any source of infection related to the implant procedure was removed from all patients. If an OAF existed in the area where the implant was removed, a Penrose drain was placed to maintain the fistula. If there was no OAF, an intentional OAF was formed through intentional perforation. Afterwards, the patient was given oral antibiotics(3rd generation Cephalosporin) and observed. The drain was removed after confirming the patency of the maxillary ostium, which was indicated by 1) symptoms of saline flowing into the nose or throat during drain irrigation, and 2) confirmation of maxillary ostium clearance on CBCT. If either of those two criteria was confirmed, the drain was removed, and the average removal period was 2nd or 3rd postoperative week. After the drain was removed, if the OAF was small, it disappeared naturally. Otherwise, the OAF closure surgery was performed under local anesthesia, at least 4 weeks after the drain removal.

None of the patients treated with the method described above required additional endoscopic sinus surgery to open the maxillary ostium.

A 63-year-old woman with hepatitis B underwent dental implant placement in the #15 and #17 area, along with a sinus bone graft at a local dental clinic. Right after the surgery, she experienced PND, facial pain, facial swelling, systemic fever, and rhinorrhea. She visited a local Ear-nose-throat(ENT) clinic for a CT scan and antibiotic medication, and was diagnosed as right maxillary sinusitis. Since the symptoms did not subside even after one week of antibiotic therapy, she visited Kyungpook National University Dental Hospital for further evaluation and treatment. According to the CBCT taken on the first day of the visit, the imaging revealed severe mucosal thickening with ostium obstruction(Fig. 1a). The #17 implant was removed using dental forceps, and a 6Fr Penrose drain was inserted to intentionally create an OAF for drainage(Fig. 1b). In the 3rd postoperative week, a follow-up CBCT revealed decreased mucosal thickening and clearance of the blocked ostium(Fig. 1c). Consequently, the drain was removed. Since the oroantral fistula was closed spontaneously and symptoms had also improved, the patient was scheduled for regular follow-up appointments without requiring additional medication therapy.

A 72-year-old woman with a history of sinusitis surgery(ESS on right maxillary sinus), hypertension, diabetes, and angina with a history of stent insertion and dual antiplatelet therapy(Aspirin, Clopidogrel), underwent implant placement in the #25~26 area with sinus bone graft at a local dental clinic in 2019. She did not experience any pain or discomfort until May 2022, when she started feeling pain in the #25~26 area, accompanied by systemic fever, swelling, and pus discharge from the gingival sulcus. The pain worsened, so she visited Kyungpook National University Dental Hospital for further evaluation. According to the CBCT taken on the first day of the visit, severe mucosal thickening and complete blockage of the ostium were observed in the left maxillary sinus(Fig. 2a). The #26 implant was removed using dental forceps, and a 6Fr Penrose drain was inserted intentionally to create an OAF for drainage(Fig. 2b). Two weeks after the surgery, a follow-up CBCT was taken, revealing a significant decrease in mucosal thickening and clear ostium patency(Fig. 2c) and the Penrose drain was removed. On the 6th week after the operation, the remaining OAF was closed using a buccal advancement flap under local anesthesia and postoperative CBCT was taken on that day, revealing a further reduction in mucosal thickening(Fig. 2d). According to the CBCT taken on the 6th postoperative month, left maxillary sinus appeared clean and free of inflammation(Fig. 2e), and the patient was then referred back to the local dental clinic for #26 implant placement.

A 60-year-old man with no prior medical history visited Kyungpook National University Dental Hospital, complaining of PND, stuffy feeling and a foul odor on the right side of his nose. He had implantation surgery for #16, 17 along with sinus augmentation, at a local dental clinic a month before. Two weeks after the implantation, the #16 implant was removed due to persistent mobility issue. After the implant was removed, symptoms of PND, stuffy nose, and a foul odor had begun. Since there was no improvement in symptoms even after taking antibiotics for 5 days at the local ENT clinic, he was referred to Kyungpook National University Dental Hospital for further evaluation and treatment. According to the CBCT taken on the first day of visit, there were severe mucosal pooling in right maxillary sinus and OAF through the #16 extraction socket(Fig. 3a). Based on the severity and invasiveness of maxillary sinusitis, the removal of the #17 implant, sinus curettage, sinus irrigation and insertion of a 6Fr Penrose drain were performed under general anesthesia(Fig. 3b). A postoperative paranasal sinus(PNS) CT was taken on the second day after the surgery, confirming the successful placement of a drain through the right maxillary sinus(Fig. 3c). According to the CBCT taken 2 weeks after the surgery, although the ostium was still blocked with inflamed mucosa, the mucosal thickening had decreased dramatically and the patient showed the sign of ostium patency when irrigating the drain with saline. Therefore, the drain was removed. On the 6th postoperative week, a follow-up PNS CT was taken and ostium patency was finally observed(Fig. 3d). On the 3rd postoperative month, an oroantral fistula in the #16~17 area was closed using a buccal advancement flap under local anesthesia. The stitches were removed a week after, and the mucosa healed favorably.

A 63-year-old man with a history of angina and stent insertion was referred from a local dental clinic due to an irregular type of right maxillary sinusitis. He had an implantation surgery on #16 area with sinus bone graft at a local dental clinic in 2022. Pain, swelling and a foul odor began in June 2023. Even after undergoing incision and drainage surgery at the local dental clinic, the symptoms persisted without any improvement. As a result, he visited Kyungpook National University Dental Hospital for further evaluation and treatment. According to the CBCT taken on the first day of the visit, severe mucosal thickening with multiple internal calcifications on right maxillary sinus floor and discontinuity of the lateral wall of right maxillary sinus was observed(Fig. 4a). The initial diagnosis for this imaging was chronic maxillary sinusitis caused by the #16 implant and infected bone graft materials. The #16 implant was removed using dental forceps, and a 6Fr Penrose drain was inserted into the extraction socket to intentionally create an OAF. Granulation tissue from the right maxillary sinus was collected and sent out for biopsy(Fig. 4b). After a week, there were no significant improvements in symptoms, so additional antibiotics were prescribed for another week. The biopsy result came out as “Malignant lymphoma, suspicious for diffuse large B-cell lymphoma.” Subsequently, the drain was removed, and the patient was referred to the hemato-oncology department for additional assessment and chemotherapy.

An 84-year-old woman with osteoporosis, hypertention, diabetes, and a history of pacemaker insertion due to AV block visited Kyungpook National University Dental Hospital in October, 2023. She had an implant on left maxillary canine area removed about 6 months ago due to peri-implantitis. In August 2023, a foul odor, pus discharge and discomfort began in the left maxillary canine and premolar area. After a month of systemic antibiotic treatment, her symptoms have improved. However, due to invasive bone destruction and severe mucosal thickening in the left maxillary sinus, she was referred to Kyungpook National University Dental Hospital for further evaluation. According to the CBCT taken on the first day of the visit, the examination revealed destruction of the sinus floor, presence of sequestrum, severe mucosal pooling, and blockage of the ostium in the left maxillary sinus(Fig. 5a). She was initially diagnosed with left maxillary sinusitis with osteomyelitis. After 2 weeks of antibiotics medication, a sequestrectomy, sinus irrigation, and insertion of a 6Fr Penrose drain were performed to intentionally create an OAF under local anesthesia. Inflammatory tissue from the sinus was collected and sent for biopsy(Fig. 5b). The biopsy result later confirmed the presence of osteomyelitis, as anticipated. On the 3rd postoperative week, the patient showed signs of ostium patency when irrigated with saline, so the drain was removed. However, the CBCT did not show any significant improvement in the degree of mucosal thickening, and the ostium was still blocked with thick mucosa containing scattered radiopaque particles, which could indicate the possibility of a fungal infection such as aspergillosis(Fig. 5c). CBCT taken on the 6th postoperative week revealed that the left maxillary sinus was still heavily filled with inflamed, thickened mucosa, and the ostium was also blocked(Fig. 5d). Due to the delayed healing of the sinusitis, a more invasive surgical intervention under general anesthesia was performed, including sequestrectomy, surgical curettage, sinus irrigation, and closure of the OAF using a buccal advancement flap(Fig. 5e). The patient visited for a postoperative check a week after the operation, and the mucosa had healed favorably. The biopsy results confirmed the presence of both aspergillosis and osteomyelitis, as suspected. According to the postoperative CBCT taken one month after the general anesthesia operation, the left maxillary sinus became clean along with the clear ostium, and the patient was referred back to the local dental clinic for additional prosthetic treatment(Fig. 5f).