Porous Hydroxyapatite Granules Research Articles

Development of porous spherical hydroxyapatite granules: application towards protein delivery.

A new method for the preparation of porous spherical hydroxyapatite granules is reported. It may be clinically applied towards orthopaedic or maxillofacial surgery as fillers or packing materials, and as biological chromatography supports. Its application towards delivery of macromolecules or protein drugs is discussed utilizing human serum albumin (HSA) as a model protein.

Bone formation by cells from femurs cultured among three-dimensionally arranged hydroxyapatite granules.

In vitro bone formation by cells derived from adult rabbit femurs was investigated on or in several substrates with small porous hydroxyapatite granules (HAGs). When the bone fragments were cultured in HAG-packed glass tubes, which were inclined (5 degrees -30 degrees ) and rotated 90 degrees per day after one week of culture, thin lamellar tissues were newly formed in narrow spaces among the HAGs. By 11 days of culture, these tissues had been mineralized except for their periphery and had well developed collagen bundles and several monolayer cells. Some cells resided in bone lacuna-like spaces. By contrast, mineralization was negligible in 6-week cultures on two-dimensional glass and polystyrene plates with or without two-dimensionally arranged HAGs on their surfaces and in three-dimensional collagen gels with or without HAGs in spite of active cell proliferation. These results suggest that osteogenesis is accelerated in a specific three-dimensional constitution of extracellular matrix and/or under the effects of mechanical forces for the new tissue and that bioactive HAGs offer favorable three-dimensional spaces for osteogenic tissue formation.

Bone formation by cells from femurs cultured among three‐dimensionally arranged hydroxyapatite granules

In vitro bone formation by cells derived from adult rabbit femurs was investigated on or in several substrates with small porous hydroxyapatite granules (HAGs). When the bone fragments were cultured in HAG-packed glass tubes, which were inclined (5°–30°) and rotated 90 degrees per day after one week of culture, thin lamellar tissues were newly formed in narrow spaces among the HAGs. By 11 days of culture, these tissues had been mineralized except for their periphery and had well developed collagen bundles and several monolayer cells. Some cells resided in bone lacuna-like spaces. By contrast, mineralization was negligible in 6-week cultures on two-dimensional glass and polystyrene plates with or without two-dimensionally arranged HAGs on their surfaces and in three-dimensional collagen gels with or without HAGs in spite of active cell proliferation. These results suggest that osteogenesis is accelerated in a specific three-dimensional constitution of extracellular matrix and/or under the effects of mechanical forces for the new tissue and that bioactive HAGs offer favorable three-dimensional spaces for osteogenic tissue formation. © 1997 John Wiley & Sons, Inc. J Biomed Mater Res, 37, 1–8, 1997.

Fabrication and characterization of porous hydroxyapatite granules

Porous hydroxyapatite granules with controlled porosity, pore size, pore size distribution, and granule size were fabricated using a drip-casting process. Granules with a wide range of porosity from 24 to 76 vol%, pore sizes from ~95 to ~400 μm, and granular sizes from 0.7 mm to ~4 mm can be obtained. This technique allows the fabrication of porous granules with desirable porous characters simulating natural bone architecture, and is expected to provide advantages for biomedical purposes.

Alloplastic Nasal and Perialar Augmentation

Our favorable experience with use of porous hydroxyapatite granules to augment the craniofacial skeleton (more than 200 patients during an 8-year period) has led us to use this method to augment the nasal skeleton in selected cases. Extensive experience has been achieved in augmenting the perialar, maxilla, and glabellar area with very favorable results. A much more limited experience has been gained in augmenting the nasal dorsum, and this method must be considered investigatory at present.

Augmentation of the atrophic maxillary alveolar ridge with hydroxyapatite granules in a Vicryl (Polyglactin 910) knitted tube and simultaneous open vestibuloplasty

A modified technique for augmentation of the severely atrophic edentulous maxillary alveolar ridge is described. The augmentation was carried out using a knitted polyglactin 910 mesh tube filled with porous hydroxyapatite granules, the tube being inserted through the access achieved by an open vestibuloplasty. The results of an in-vivo animal study showed that the absorption of the mesh was complete between 49 and 70 days. The clinical study included 11 patients in all of whom there was severe maxillary ridge atrophy and major prosthetic problems; follow-up was for a mean of 25 months. The procedure was without significant complication and produced a mean immediate absolute augmentation of 5.5 mm and substantially increased vestibular depth. A gradual reduction of ridge height was found over time. Nevertheless all patients showed significantly increased ability to wear their dentures. The technique is presented as a safe and predictable alternative to the use of bone grafts and titanium implants in these severely atrophic cases.

Augmentation of the Craniofacial Skeleton with Porous Hydroxyapatite Granules

Augmentation of the Craniofacial Skeleton with Porous Hydroxyapatite Granules

Augmentation of the Craniofacial Skeleton with Porous Hydroxyapatite Granules

Augmentation of the Craniofacial Skeleton with Porous Hydroxyapatite Granules

Augmentation of the Craniofacial Skeleton with Porous Hydroxyapatite Granules

Augmentation of the Craniofacial Skeleton with Porous Hydroxyapatite Granules

Augmentation of the Cheekbones With Porous Hydroxyapatite Granules

Augmentation of the Cheekbones With Porous Hydroxyapatite Granules

Augmentation of the Craniofacial Skeleton with Porous Hydroxyapatite Granules

Augmentation of the craniofacial skeleton with porous hydroxyapatite granules (Interpore 200) has been performed in 52 sites on 43 patients. Follow-up extends to 5 years, and 26 patients have been followed for greater than 1 year with excellent results. The procedure has been used for reconstruction of congenital and posttraumatic deformities and for purely aesthetic purposes. Areas that have benefited from hydroxyapatite augmentation include the skull, zygomaticomaxillary region, lateral mandible, perialar region, periorbital area, and temporal region. There have been no cases of infection, and only two patients have required minor revisions. Resorption has not occurred.

Augmentation of the Craniofacial Skeleton with Porous Hydroxyapatite Granules

Augmentation of the Craniofacial Skeleton with Porous Hydroxyapatite Granules

Evaluation of the interface between calcified bone and metal implants

In recent years oral endosteal implants have been placed in healed extraction sites but it has been suggested that osseointegration may not occur. This study places IMZ implants1 in fresh extraction sites with and without two biological graft materials: porous hydroxyapatite granules (HA) and polytetrafluorethylene (PTFE) membranes. The purpose of this study was to investigate the influence of immediate placement of implants on osseointegration. This presentation uses the scanning electron microscope (SEM) to evaluate the relationship of implant to bone. In addition, the effect of these two graft materials on bone regeneration and prevention of soft tissue (ST) ingrowth was examined. Under anesthesia three adult mongrel dogs had premolars extracted bilaterally from the mandible. Using the IMZ system six implant sites were prepared, five implants placed in alveolar bone and the sixth site was a no implant control. A total of fifteen implants were placed in the area between the canine and first molar of the three animals.

アパタイトか粒により挙上した顎堤へのインプラント適用に関する実験的研究 アパタイトインプラントと骨付きアパタイトインプラントの組織学的観察

The purpose of this study was to investigate the possibility of applying the hydroxyapatite implant and the hydroxyapatite implant covered with autogenous iliac bone to the augmented mandible. Three months after the extractions of the lower P3, P4, and M1 of mongrel dogs, alveolar ridge augmentations were performed widely with porous hydroxyapatite granules. After one month, the hydroxyapatite implants were inserted in the iliac bone of the same dog. Four months after the augmentation, the hydroxyapatite implant and the hydroxyapatite implant covered with autogenous iliac bone were implanted only in the augmented area with the granules of the mandible. Two months later, specimens were taken out and fixed by 10% formalin alcohol. They were embedded in polyester resin and undecalcified sections were prepared. The sections were stained with toluidine blue and observed under light microscope. 1) Bone ingrowth was seen in most parts of the intergranular spaces and in some spaces fibrous connective tissues were observed. 2) The hydroxyapatite implant was partly attached to the bone. But a large surface of the implant was connected to the fibrous tissues among the granules. 3) The hydroxyapatite implant covered with the iliac bone was combined with the bone of the intergranular spaces.

The Use of Porous Hydroxyapatite Granules to Eliminate the Hourglass Deformity in Advancement Genioplasty

The Use of Porous Hydroxyapatite Granules to Eliminate the Hourglass Deformity in Advancement Genioplasty

歯槽骨欠損部への多孔質アパタイトか粒充填に関する組織学的観察

The purpose of this study was to observe the regeneration of the periodontal tissue using porous hydroxyapatite granules in experimental periodontal lesions. The upper lateral incisors of three Macaca fuscatae were extracted. After a 12-week recovery period, three wall infrabony defects were surgically prepared on the distal surface of the central incisors. In order to accumulate the plaque and cause inflammation, a wire with dental floss was placed inside the defects for a period of four weeks and then removed. Flap operations were performed and porous hydroxyapatite granules were placed into the defects. Twelve weeks after surgery, the samples were taken out and fixed in glutaraldehyde solution. They were embedded in polyester resin and undecalcified sections were prepared. The specimens were stained with toluidine blue and observed under light microscope. 1) The implanted area was divided into three distinctive zones. The first zone was located distally and occupied two-thirds of the total area. A large quantity of osseous tissue was detected. The second zone was situated near the root and presented only a small quantity of osseous tissue; Fibrous connective tissue predominated in the third zone adjacent to the root. 2) Bone apposition and resorption caused by physiologic mobility and movement of the teeth were observed. These results suggest that the elimination of the functional forces is advisable during the healing period whenever hydroxyapatite granules are placed into the periodontal defect.

多孔質アパタイト顆粒のイヌ歯槽骨欠損部への応用に関する神経病理組織学的研究

多孔質アパタイト顆粒のイヌ歯槽骨欠損部への応用に関する神経病理組織学的研究

Histological investigation of improvement of mandibular atrophy for application of hydroxyapatite dental implant

The purpose of this study was to investigate the possibility of applying the hydroxyapatite dental implant to the atrophic mandible after alveolar ridge augmentation using hydroxyapatite granules. The lower P3, P4 and M1 of 3 mongrel dogs were extracted. At 30 weeks, alveolar ridge augmentation was performed with porous hydroxyapatite granules. Sixteen weeks later, hydroxyapatite dental implants were applied to the area. And 4 weeks later, the specimens were taken out and fixed by 10% formalin alcohol. They were embedded in polyester resin and prepared into undecalcified sections. And the sections were stained with toluidine blue to observe the surrounding tissue of the dental implants histologically under light microscopy. 1) Bone formation was seen in most part of the intergranular spaces. However, in the buccal area, there were some spaces in which bone formation was entirely not observed. 2) At 4 weeks after implantation, almost all of the surface of the hydroxyapatite dental implants was attached to the surrounding osseous tissues. But in some parts of the implant surface, especially the buccal, fibrous connective tissue was seen. 3) These results provide a basis for the technique of hydroxyapatite dental implantation with porous hydroxyapatite granules in the atrophic mandibles after alveolar ridge augmentation.

Effect of porous and dense hydroxyapatite implantation on periodontal tissue regeneration in monkeys.

Two different kinds of hydroxyapatite (HA) granules (size: 400-630 microns), 1) porous HA fabricated by the H2O2 bubbling method and 2) dense HA, were placed into the experimentally created, 3-wall, wide periodontal defects in two monkeys to evaluate whether the different structures of hydroxyapatite influence the periodontal response after implantation. Defects without HA implantation served as controls. The HA implant groups showed excellent biocompatibility. Both the porous HA and the dense HA showed a greater amount of "connective tissue attachment or adhesion" than the control group. The amount of the increase by the porous HA group was statistically significant when compared with the control group. However, the three groups showed a similar amount of new cementum formation. These results indicate that the improvement of tissue regeneration by hydroxyapatite implantation was probably due to the prevention of the epithelial downgrowth rather than to the acceleration of the coronal proliferation of the periodontal ligament cells. In the porous HA group, ingrowth of fibrous and osseous tissue in the HA and indefinite tissue-apatite interface were observed. These findings suggest that the porous HA granules formed a firmer attachment to the surrounding periodontal tissue.

Porous hydroxyapatite granules: their synthesis, application and characterisation

A porous granular hydroxyapatite (PGHA) produced by vibration and rolling has been developed. Its physical and chemical properties show that it is suited to the demands of bone implantation. Animal experiments indicate that new bone can grow not only in the gaps between the granules but also through the internal pores of the PGHA. The bony ingrowth increases the strength and flexibility of the implant, and makes the properties of the implant more like those of natural bone than of dense hydroxyapatite. A 2-year clinical follow-up study has shown satisfactory results.