Long-term radiographic assessment of maxillary sinus floor augmentation using beta-tricalcium phosphate: analysis by cone-beam computed tomography

Background: The long-term stability of maxillary sinus floor augmentation with beta-TCP remains largely unknown. We report the long-term assessment of volumetric changes in maxillary sinus floor augmentation with beta-TCP by cone-beam computed tomography (CBCT). Methods: The subjects included 30 patients who underwent maxillary sinus floor augmentation using beta-TCP and 58 implant placement for unilateral maxillary defect, simultaneously. Volumetric changes in beta-TCP and the height of peri-implant bone were analyzed by CBCT. Results: In all patients, the mean volume of the grafted bone decreased from immediately after implant placement to 6 months after implant placement (75.6 % reduction rate); it decreased further at 2.5 years after implant placement (54.9 % reduction rate). The mean of the height from the implant tip to the maxillary sinus floor was 2.00 +/- 1.51 mm, 0.73 +/- 1.33 mm, and -0.72 +/- 1.11 mm immediately, 6 months, and 2.5 years after implant placement, respectively. The implant tip protruded beyond the maxillary sinus floor in approximately 70 % of the implants (41/58 implants) at 2.5 years after surgery. During the observation period, the implant survival rate was 100 %. Conclusions: The radiographic analysis by CBCT is considerably more advanced than previous radiographic examinations. Although maxillary sinus pneumatization continues to progress >= 1 year after maxillary sinus floor augmentation with beta-TCP, it stabilizes 3 years after surgery.