A case report of acute pyelonephritis secondary to maxillary sinusitis caused by implant displacement

With the advancement of dental implant technology, implant placement in the maxillary posterior region has become a primary method for restoring missing teeth. However, due to factors such as significant maxillary sinus pneumatization and insufficient alveolar bone volume, implant displacement into the maxillary sinus occasionally occurs. Retained implants in the maxillary sinus may induce maxillary sinusitis and secondary systemic diseases such as pyelonephritis. The relevance of which has not yet been fully recognized and thoroughly studied.

A 47-year-old male patient presented to the nephrology department with urinary frequency and urgency with fever. He was diagnosed with pyelonephritis and given a standard antibiotic regimen, which did not effectively control his condition. Further examination revealed that the first implant on the right side was connected to the maxillary sinus, while the second implant had become completely displaced into the maxillary sinus, resulting in maxillary sinusitis. However, due to the limited field of view of the CBCT, the second implant was not detected during the initial examination. The patient was given a maxillary sinus foreign body removal with complete drainage and continued antibiotic therapy. The patient's maxillary sinusitis and pyelonephritis were cured and did not recur during the 8-year follow-up.

This case demonstrates the risk of maxillary sinusitis due to implant displacement into the maxillary sinus. Severe maxillary sinusitis with secondary systemic diseases is possible. Moreover, for maxillary sinusitis caused by dislodged implants, simple antibiotic treatment is often difficult to be effective, and the cause of the disease needs to be removed as early as possible.