Challenges associated with reentry maxillary sinus augmentation

Objective: This study was a retrospective assessment of reentry sinus augmentation compared with sinus augmentation performed for the first time. Study design: There were 38 subjects who required sinus augmentation. The study group (17 patients, 21 sinuses) included subjects following failure of a previous sinus augmentation procedure that required reentry augmentation. The control group (21 patients, 21 sinuses) included subjects in which sinus augmentation was performed for the first time. Patients' medical files were reviewed. A preformed questionnaire was used to collect data regarding demographic parameters, medical and dental health history, habits, and intra- and postoperative data. Results: Operative challenges in the study group included adhesions of the buccal flap to the Schneiderian membrane (62%, 13/21, P < .001), bony fenestration of the lateral wall with adhesions (71%, 15/21, P < .001), limited mobility of a clinical fibrotic Schneiderian membrane (71%, 15/21, P < .001), and increased incidence of membrane perforations (47%, 10/21, versus 9.5%, 2/21, P = .03). In the control group the Schneiderian membrane was thin and flexible. Sinus augmentation succeeded in all cases of both groups. Implant failure was significantly higher in the study group (11% versus 0%, P < .001). Conclusions: Clinical success of reentry sinus augmentation is predictable despite its complexity. Clinicians should be aware of anatomical changes caused by previous failure of this procedure. Patients should be informed about the lower success rate of implants when reentry sinus augmentation is required.