목적: Dental procedures and odontogenic pathologies in the maxilla may result in odontogenic sinusitis (ODS). With the increase in the patients receiving dental implants, the protrusion of dental implants in the maxillary sinus (MS) is a frequently encountered finding in ENT practice. Therefore, the authors aimed to reveal the impact of protruded dental implants in patients diagnose with ODS. 방법:Patients who underwent unilateral functional endoscopic sinus surgery (FESS) for the treatment of ODS were retrospectively reviewed. Among those patients, patients with bilateral dental implantation in the maxilla were selected for the study. Presence of implant protrusion into the MS, alveolar process bony osteolysis, loss of maxillary floor cortical lining, and the presence of the bone graft was reviewed. 결과:Total number of 33 patients underwent FESS in the diagnosis of unilateral ODS with bilateral maxillary dental implantation. In 66 maxillary sinuses, the rate of implant protrusion into the MS showed 22 (66.7%) in the ODS side, and 17 (51.5%) in the normal MS, not showing significant differences. Between the ODS side and normal MS, the loss of maxillary floor cortical lining (16 (48.5%) and 5 (15.2%), respectively) and osteolysis of the alveolar process surrounding the implant (17 (52.5%) and 5 (15.2%), respectively) showed significant difference (p value < 0.05, both). Bone graft was identified in 10 (30.3%) and 8 (24.2%) in two groups, showing no significant difference. However, the ODS side showed significantly higher rate of erosion or dehiscence of the bone graft 10 (100%), compared to the normal side 1 (12.5%) (p<0.05). 결론:Our results show that protrusion of dental implants into the MS does not seem to correlate with ODS. However, the osteolysis of the adjacent alveolar process, cortical dehiscence of the maxillary sinus, and bone graft erosion following the implant insertion might attribute in the development of ODS.