Sinus floor bone failures in maxillary sinus floor augmentation: a case-control study

Extreme bone resorption in posterior maxilla may lead to absence of part of the sinus floor. This phenomenon has been termed sinus floor bone failure, and may compromise sinus floor augmentation.

The present article aims to evaluate risk factors related to sinus floor bone failures and to evaluate the influence of these failures in sinus floor augmentation outcomes in patients with severely atrophic posterior maxilla.

In this case-control study, patients were selected among those referred for sinus floor augmentation. Only patients presenting a ridge bone height of less than 3 mm were included. Cases were defined as presenting sinus floor bone failure, whereas controls did not present any interruption in the sinus floor bone. Information collected included clinical dental records and computed tomographic assessment of sinus width, septa, and schneiderian membrane. Risk estimates for sinus floor bone failures were calculated as adjusted odds ratios (AORs) with 95% confidence intervals (CIs) using conditional logistic regression analyses. A p value under 0.05 was considered statistically significant. In addition, sinus floor augmentation outcomes of both groups were also assessed.

In all, 23 cases and 58 controls were included in the study. Sinus floor bone failures were significantly associated with the number of missing posterior teeth (AOR 3.67; 95% CI 0.86 to 15.63; p = .046) and a history of periodontitis (AOR 6.39; 95% CI 1.86 to 21.95; p = .002). Of the total, 15 cases and 27 controls underwent sinus floor augmentation. Schneiderian membrane perforation occurred during the surgery of two cases and of one control. No implants were lost during a mean postsurgical follow-up of 20 months.

The number of missing posterior teeth and a history of periodontitis may be considered as risk factors for sinus floor bone failures.