Abstract
<jats:p>Background. Subantral augmentation in the presence of maxillary sinus floor defects (MSFD) remains insufficiently standardized and may be associated with a higher risk of complications compared with “standard” conditions of an intact sinus floor. The aim of this study is evaluation the outcomes of subantral augmentation in patients with MSFD using a newly developed differentiated protocol and to compare these outcomes with those achieved under standard conditions.Materials and methods. This prospective cohort study (2022–2026) included 92 patients: 31 in the MSFD group and 62 in the control group with an intact sinus floor. In the MSFD group, subantral augmentation was performed according to a differentiated algorithm based on a topographic–anatomical classification of defects. Between-group differences were assessed using Fisher’s exact test.Results. The overall success rate of subantral augmentation was higher in the control group than in the MSFD group (100% [61/61] vs 80.6% [25/31]), with six failures in the MSFD group (p = 0.001). The lateral window approach predominated in controls (72.1%), whereas in the MSFD group the most common technique was transcrestal subantral augmentation combined with alveolar ridge augmentation (80.6%). Postoperative complications were less frequent in the control group: infectious complications occurred in 4.9% (3/61) vs 25.8% (8/31), and maxillary sinusitis in 3.3% (2/61) vs 22.6% (7/31) in the MSFD group (both p = 0.006). After successful augmentation, implant outcomes were comparable between groups: implant disintegration occurred in 4/52 implants (92.3% success) in the MSFD group and in 3/82 implants (96.3% success) in controls (p > 0.05). Schneiderian membrane perforation was observed more often in the control group (19.6% vs 6.4%), although the difference was not statistically significant (p > 0.05).Conclusions. A differentiated protocol for subantral augmentation in patients with MSFD yields acceptable success rates; however, MSFD should be considered a risk factor primarily for infectious complications and maxillary sinusitis. When augmentation is successful, implant outcomes are comparable with those achieved under standard conditions.</jats:p>