Are gingival phenotype, residual ridge height, and membrane thickness critical for the perforation of maxillary sinus?

BACKGROUND: Sinus membrane perforation is the most common complication of the sinus-augmentation procedure. Anatomic factors have been implicated in the risk of sinus membrane perforation (SMP) during sinus-lift surgery. However, there are no reports on the relationships among gingival phenotype (GP), residual ridge height (RRH), membrane thickness (MT), and perforation rate of the maxillary sinus. Therefore, the aim of this clinical study is to determine the associations among GP, RRH, MT, and SMP rate.

METHODS: Forty-four patients (64 sinus-lift procedures) were included in the study. Preoperative computed tomography scanning was performed to radiographically evaluate GP, RRH, and MT. The smallest RRH, highest MT, and gingival thickness values were recorded. These values were classified as follows: RRH, < or >3.5 mm; MT, < or >1 mm; and GP, <1.5 or >2 mm. Sinus-lift surgery was performed with a lateral window approach, and SMPs were detected at 11 sinus sites. Perforation size and locations were recorded, and the perforations were repaired with collagen membrane. One hundred seventy-six implants were placed immediately after augmentation procedure.

RESULTS: Strong correlations of GP with RRH (r = 0.722, P = 0.001) and MT (r = 0.702, P = 0.001) were noted. Moderate correlations were found between RRH and MT (r = 0.596, P = 0.001) and between MT and SMP (r = 0.417, P = 0.001). Furthermore, mild correlations of SMP with RRH (r = 0.290, P = 0.020) and GP (r = 0.248, P = 0.04) were established. Four implants were lost, but no significant difference was found between implant failure and SMP.

CONCLUSION: Within the limits of the study, it may be suggested that GP, RRH, and MT may be important factors for sinus perforation.