BackgroundThe long-term stability of maxillary sinus floor augmentation with β-TCP remains largely unknown. We report the long-term assessment of volumetric changes in maxillary sinus floor augmentation with β-TCP by cone-beam computed tomography (CBCT).MethodsThe subjects included 30 patients who underwent maxillary sinus floor augmentation using β-TCP and 58 implant placement for unilateral maxillary defect, simultaneously. Volumetric changes in β-TCP and the height of peri-implant bone were analyzed by CBCT.ResultsIn 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 %.ConclusionsThe 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 β-TCP, it stabilizes 3 years after surgery.

Highly pure β-TCP is a safe bone-grafting material with superior osteoconductive properties. Histologic and radiographic examinations indicate that β-TCP is slowly resorbed, which results in unresorbed graft material remaining even 6 months after the procedure, and that new bone replacement occurs slowly for approximately 1 year.

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