[Preliminary observation of the impact by alveolar ridge preservation on maxillary sinus in patients with severe periodontitis: a retrospective study].

Objective: To investigate the ameliorative effect of alveolar ridge preservation (ARP) on maxillary sinus mucosal thickening caused by severe periodontitis, as well as its positive significance in preventing the occurrence of pathological maxillary sinus pneumatization. Methods: This retrospective study included 49 patients with severe periodontitis who underwent unilateral ARP of maxillary molar at the Department of Periodontology, School and Hospital of Stomatology, China Medical University, between April 2020 and April 2025. A total of 98 sites were analyzed, including 49 ARP sites and 49 contralateral control sites. According to the completeness of follow-up cone beam CT (CBCT) data and the study objectives, the analysis was divided into two parts: ①Longitudinal study: 31 patients with complete preoperative and 6-month postoperative CBCT records were included (31 ARP sites) to evaluate changes in residual alveolar bone height and maxillary sinus vertical height before and after surgery. Among these, 18 sites with odontogenic maxillary sinusitis (OMS) at baseline were further analyzed for changes in Schneiderian membrane thickness. ②Cross-sectional study: 40 patients with complete 6-month postoperative CBCT records were included (80 sites in total). The maxillary sinus vertical height at ARP sites was compared with that at contralateral naturally healed post-extraction sites (12 pairs) or contralateral healthy natural tooth sites (28 pairs). Results: In the longitudinal analysis, the vertical alveolar bone height at ARP sites significantly increased from 3.60(1.77, 5.82) mm at baseline to 6.84(4.96, 9.46) mm at 6 months postoperatively (n=31, Z=4.74, P<0.05), whereas no significant change was observed in maxillary sinus vertical height (P>0.05). At sites with OMS, Schneiderian membrane thickness significantly decreased from 5.13 (3.17, 10.90) mm preoperatively to 1.19 (0.57, 2.09) mm at 6 months postoperatively (n=18, Z=-3.62, P<0.05). In the cross-sectional analysis, the maxillary sinus vertical height at ARP sites [33.69 (28.97, 36.70) mm] was significantly lower than that at contralateral naturally healed post-extraction sites [36.45(32.76, 39.08) mm] (n=12, Z=2.98, P<0.01), while with no significant difference compared to contralateral healthy natural tooth sites (P>0.05). After adjustment for age and sex, maxillary sinus vertical height was negatively correlated with residual alveolar bone height (rpartial=-0.448, P<0.001). Conclusions: ARP may help reduce Schneiderian membrane thickening associated with severe periodontitis and may have potential clinical value in limiting post-extraction maxillary sinus pneumatization.