Application of low-crystalline carbonate apatite granules in 2-stage sinus floor augmentation: a prospective clinical trial and histomorphometric evaluation

Abstract

Purpose: The purpose of this study was to elucidate the efficacy and safety of carbonate apatite (CO 3 Ap) granules in 2-stage sinus floor augmentation through the radiographic and histomorphometric assessment of bone biopsy specimens. Methods: Two-stage sinus floor augmentation was performed on 13 patients with a total of 17 implants. Radiographic assessment using panoramic radiographs was performed immediately after augmentation and was also performed 2 additional times, at 7±2 months and 18±2 months post-augmentation, respectively. Bone biopsy specimens taken from planned implant placement sites underwent micro-computed tomography, after which histological sections were prepared. Results: Postoperative healing of the sinus floor augmentation was uneventful in all cases. The mean preoperative residual bone height was 3.5±1.3 mm, and this was increased to 13.3±1.7 mm by augmentation with the CO 3 Ap granules. The mean height of the augmented site had decreased to 10.7±1.9 mm by 7±2 months after augmentation; however, implants with lengths in the range of 6.5 to 11.5 mm could still be placed. The mean height of the augmented site had decreased to 9.6±1.4 mm by 18±2 months post-augmentation. No implant failure or complications were observed. Few inflammatory cells or foreign body giant cells were observed in the bone biopsy specimens. Although there were individual differences in the amount of new bone detected, new bone was observed to be in direct contact with the CO 3 Ap granules in all cases, without an intermediate layer of fibrous tissue. The amounts of bone and residual CO 3 Ap were 33.8%±15.1% and 15.3%±11.9%, respectively. Conclusions: In this first demonstration, low-crystalline CO 3 Ap granules showed excellent biocompatibility, and bone biopsy showed them to be replaced with bone in humans. CO 3 Ap granules are a useful and safe bone substitute for two-stage sinus floor augmentation.

Carbonate apatite artificial bone

“…The first human clinical trial was performed at three university hospitals in patients requiring sinus floor augmentation [ 33 , 34 ]. Figure 7 illustrates the procedure for two-stage sinus floor augmentation [ 34 ].…”

“…The first human clinical trial was performed at three university hospitals in patients requiring sinus floor augmentation [ 33 , 34 ]. Figure 7 illustrates the procedure for two-stage sinus floor augmentation [ 34 ]. After the sinus floor membrane was elevated with a mucosal elevator, CO 3 Ap granules were placed in the elevated space ( Figure 7(b )).…”

“…Figure 8 summarizes the micro-computed tomography (μ-CT) images and the appearance of biopsy tissue stained with hematoxylin and eosin (H-E) or VG. CO 3 Ap granules were replaced with new bone, even though a small amount of CO 3 Ap granules remain at this stage [ 34 ]. The presence of both mature bone and osteoids indicated active bone remodeling.…”

“…The mean preoperative residual bone height of 3.4 ± 1.3 mm was increased to 13.0 ± 1.9 mm by the sinus floor augmentation using the CO 3 Ap granules. Since the height after sinus floor augmentation is sufficient for dental implants, all patients received dental implants without any problems [ 33 , 34 ]. Based on the trial results, CO 3 Ap granules were approved for clinical use as Cytrans Granules (GC Co, Tokyo, Japan) by the Pharmaceuticals and Medical Devices Agency (PMDA) in 2017.…”

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Figure 8. Photo, μ-CT scanning, H-E and VG staining of a histological specimen biopsied from a patient who underwent two-stage sinus floor augmentation for dental implantation [ 34 ]

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