Effects of missing teeth and nasal septal deviation on maxillary sinus volume: a pilot study

Purpose Tooth extraction and the projection of the tooth roots into the maxillary sinus are reported to greatly reduce the bone height from the alveolar ridge to the maxillary sinus floor, while missing teeth are reported to lead to the expansion of the maxillary sinus, all of which are important considerations during dental implant treatment for the maxillary molar region. Therefore, assessing the anatomical characteristics of the maxillary sinus acting as complicating factors is crucial before sinus augmentation. We conducted a three-dimensional examination of the effects of missing teeth and nasal septal deviation (NSD) on maxillary sinus volume (MSV). Methods We selected participants with two or more missing teeth from patients who underwent maxillary sinus augmentation for a unilateral free-end saddle between April 2019 and December 2020. We calculated the MSV and NSD using cone-beam computed tomography (CBCT). We compared the relationships of the presence/absence of teeth and NSD with MSV bilaterally in each patient using the Wilcoxon t-test. p-values < 0.05 denoted statistical significance. Results This study included 30 patients (30 sinuses; 12 men, 18 women). The average patient age was 58.2 +/- 10.2 years (men, 60.4 +/- 3.7 years; women, 59.2 +/- 4.5 years; range, 40-77 years). The mean number of missing teeth was 2.98 +/- 1.01: 13 patients had two missing teeth and 17 had three or more missing teeth. Nine patients (30%) had NSD. The mean MSV on the ipsilateral and contralateral sides of the NSD was 21.50 +/- 3.84 cm(3) and 22.10 +/- 3.56 cm(3), respectively; thus, NSD did not affect MSV (p = 0.150). The mean MSV on the edentulous and non-edentulous sides was 21.58 +/- 3.89 cm(3) and 21.77 +/- 4.30 cm(3), respectively; thus, the MSV was significantly smaller on the edentulous side (p = 0.00036). Conclusion Although this study was a limited preoperative study, three-dimensional measurement of the maxillary sinus with CBCT in partially edentulous patients revealed that missing teeth lead to substantial reductions in MSV, while NSD was not associated with MSV.