Bacterial Influence on Consolidation of Bone Grafts in Maxillary Sinus Elevation

Abstract

Objectives: The aim of this study was to identify microorganisms present on the maxillary sinus floor at the moment of sinus elevation surgery and, using tomography, to investigate the repercussions these might have for regenerated bone 9 months after the procedure. Materials and methods: 174 patients (90 women and 84 men) with a mean age of 55.92 years underwent 227 sinus elevations (120 left sinus, 107 right sinus). As the membrane was lifted, a sample of the maxillary sinus floor was collected with a cotton swab, and placed on a blood agar and chocolate agar culture to incubate for 48 h at 37°C; the samples then underwent microbiological analysis. Orthopantomographs and computerized tomographs were made immediately after the sinus grafting and after 9 months to measure the amount of remaining and regenerated bone in vertical and transversal direction. Results: 18.1% of 227 cultures were bacteria-positive. 45% of the germs were of the Streptococcus genus, most of which belonged to the S. viridans group (61.1%). Patients presenting negative cultures had 5% more regenerated bone than patients with bacteria-positive cultures, which represents an additional 2.28 mmof vertical bone (with a confidence interval between 0.83 mm and 3.73 mm). Conclusions: Patients with bacteria-positive cultures obtained previously to the sinus grafting procedure have greater risk of bone height loss after 9 months, which indicates that bacterial contamination may influence bone graft regeneration.