2016 年 29 巻 1 号 p. 20-28
Objectives : This study aimed to reveal the effect of maxillary sinus floor augmentation (“sinus lift”) on the maxillary sinus by examining changes in the thickness of the maxillary sinus mucosal membrane (MSM). Here, we report interesting findings.
Materials and Methods : The subjects were 30 patients (54 fixtures or sites) who had undergone piezoelectric surgery (piezosurgery) for sinus lift and concurrent implant placement using a lateral approach. The mean age of patients was 53.6±14.5 years. Dental cone beam computed tomography (CBCT) was performed at the time of preoperative examination and postoperatively at 7.6±2.4 months (range, 4.7-14.5 months) before the second stage of surgery. Coronal and sagittal images were acquired for the measurement of MSM thickness in implant sites (maximum thickness in a 10-mm square covered by the buccal, lingual, mesial, and distal margins). Statistical analysis was performed to compare MSM thicknesses between the preoperative and postoperative groups and between different implant material groups (autologous bone, artificial bone, and no bone graft groups). MSM was also examined in patients with intraoperative maxillary sinus perforation to evaluate healing.
Results : Mean preoperative and postoperative MSM thicknesses were 1.54±1.33 and 2.27±1.50 mm, respectively, with a significant difference between the groups (p＜0.01, Wilcoxon signed-rank test). The mean increment in the MSM thickness after surgery was 0.70±1.21 mm. The thickness of MSM postoperatively increased in 30 sites (60%) but decreased in 5 sites (10%) . Intraoperative perforation was observed in 3 sites (5.6%).
Discussion and Conclusion : In many implant sites, the MSM thickened after sinus floor augmentation in response to surgical stimuli. However, no significant changes due to different implant materials were observed. In the cases of intraoperative perforation, marked thickening of the MSM was noted immediately after surgery. When no maxillary sinus infection was observed within several months after surgery, the MSM steadily returned to its original thickness. The present findings show that careful observation of the MSM is an important means to judge post-perforation healing.
