title: Long-term radiographic assessment of maxillary sinus floor augmentation using beta-tricalcium phosphate: analysis by cone-beam computed tomography.
abstract: BACKGROUND
  The 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).
  
  
  METHODS
  The 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.
  
  
  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 β-TCP, it stabilizes 3 years after surgery.
authors.affiliation: Clinic for Implant Dentistry, Dental Hospital, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan. okatune@masaka-dental.com.
authors.forename: Tsuneji
authors.initials: T
authors.lastname: Okada
authors.affiliation: Clinic for Implant Dentistry, Dental Hospital, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Kanai
authors.affiliation: Clinic for Implant Dentistry, Dental Hospital, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8549, Japan.
authors.forename: Noriko
authors.initials: N
authors.lastname: Tachikawa
authors.affiliation: Oral Implantology Department of Prosthodontic Dentistry for Function of TMJ and Occlusion, Kanagawa Dental University, 82, Inaokachou, Yokosuka-shi, 238-8580, Kanagawa, Japan.
authors.forename: Motohiro
authors.initials: M
authors.lastname: Munakata
authors.affiliation: Oral Implantology and Regenerative Dental Medicine, Department of Masticatory Function Rehabilitation, Division of Oral Health Sciences, Graduate School of Medical Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan.
authors.forename: Shohei
authors.initials: S
authors.lastname: Kasugai
keywords: Beta-tricalcium phosphate; CBCT analysis; Maxillary sinus floor augmentation