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Autologous bone grafting is the primary method for treating alveolar clefts. However, bone grafting materials are desired as alternatives to autogenous bone to reduce surgical invasiveness. Here, we present an animal study evaluating the effect of carbonate apatite (CA) on the spontaneous eruption of permanent teeth. The bone grafting materials included CA, natural bovine bone (BB), and hydroxyapatite (HA). In 15 8-week-old male beagle dogs, the left mandibular deciduous premolars (DP) two and three were extracted and subsequently filled with CA, BB, and HA. The animals were euthanized after a predetermined number of days, and samples were collected for microcomputed tomography and histological evaluation. Spontaneous eruption of the succeeding permanent teeth (P3 and P4) was observed in the CA group at 14 weeks. Delayed eruption of the succeeding permanent teeth was observed in the BB and HA groups. CA could serve as a viable alternative to autogenous bone for treating alveolar clefts. [ABSTRACT FROM AUTHOR]

Carbonate apatite (CO3Ap) is a bioceramic material with excellent properties for bone and dentin regeneration. To enhance its mechanical strength and bioactivity, silica calcium phosphate composites (Si-CaP) and calcium hydroxide (Ca(OH)2) were added to CO3Ap cement. The aim of this study was to investigate the effect of Si-CaP and Ca(OH)2 on the mechanical properties in terms of the compressive strength and biological characteristics of CO3Ap cement, specifically the formation of an apatite layer and the exchange of Ca, P, and Si elements. Five groups were prepared by mixing CO3Ap powder consisting of dicalcium phosphate anhydrous and vaterite powder added by varying ratios of Si-CaP and Ca(OH)2 and 0.2 mol/L Na2HPO4 as a liquid. All groups underwent compressive strength testing, and the group with the highest strength was evaluated for bioactivity by soaking it in simulated body fluid (SBF) for one, seven, 14, and 21 days. The group that added 3% Si-CaP and 7% Ca(OH)2 had the highest compressive strength among the groups. SEM analysis revealed the formation of needle-like apatite crystals from the first day of SBF soaking, and EDS analysis indicated an increase in Ca, P, and Si elements. XRD and FTIR analyses confirmed the presence of apatite. This combination of additives improved the compressive strength and showed the good bioactivity performance of CO3Ap cement, making it a potential biomaterial for bone and dental engineering applications. [ABSTRACT FROM AUTHOR]

Bone augmentation using artificial bone is an important option in dental defect prostheses. A bone substitute using carbonate apatite (CO3Ap), an inorganic component of bone, was reported to have promising bone formation and bone replacement ability. However, the osteoinductivity of artificial bone is less than autogenous bone (AB). In this study, CO3Ap with AB is demonstrated as a clinically effective bone substitute. For in vitro experiments, an osteoclast-like cell (RAW-D) was cultured in the presence of AB, CO3Ap, or both (Mix), and the number of osteoclasts was evaluated. Osteoblasts were also cultured under the same conditions, and the number of adherent cells was evaluated. For in vivo experiments, a few holes were created in the rat tibia and AB, CO3Ap, or Mix were added. At 0, 14, and 21 days, the tissue morphology of the wound area was observed, and the thickness of the cortical bone was measured. In vitro, Mix did not increase the number of osteoclasts or osteoblasts. However, in vivo, the rate of bone replacement remarkably increased with Mix on dome-shape. A bone-grafting material combining osteoinductive AB with abundant artificial bone is expected to be clinically easy to use and able to form bone. [ABSTRACT FROM AUTHOR]

Carbonate apatite (CO3Ap) block, which is a bone replacement used to repair defects, was fabricated through a dissolution-precipitation reaction using a calcium hydrogen phosphate dihydrate (DCPD) block as a precursor. When the DCPD block was immersed in NaHCO3 or Na2CO3 solution at 80 °C, DCPD converted to CO3Ap within 3 days. β-Tricalcium phosphate was formed as an intermediate phase, and it was completely converted to CO3Ap within 2 weeks when the DCPD block was immersed in Na2CO3 solution. Although the crystal structures of the DCPD and CO3Ap blocks were different, the macroscopic structure was maintained during the compositional transformation through the dissolution-precipitation reaction. CO3Ap block fabricated in NaHCO3 or Na2CO3 solution contained 12.9 and 15.8 wt % carbonate, respectively. The diametral tensile strength of the CO3Ap block was 2 MPa, and the porosity was approximately 57% regardless of the carbonate solution. DCPD is a useful precursor for the fabrication of CO3Ap block. [ABSTRACT FROM AUTHOR]

Carbonate apatite (CO3Ap) foam has gained much attention in recent years because of its ability to rapidly replace bone. However, its mechanical strength is extremely low for clinical use. In this study, to understand the potential of gelatin-reinforced CO3Ap foam for bone replacement, CO3Ap foam was reinforced with gelatin and the resulting physical characteristics were evaluated. The mechanical strength increased significantly with the gelatin reinforcement. The compressive strength of gelatin-free CO3Ap foam was 74 kPa whereas that of the gelatin-reinforced CO3Ap foam, fabricated using 30 mass % gelatin solution, was approximately 3 MPa. Heat treatment for crosslinking gelatin had little effect on the mechanical strength of the foam. The gelatin-reinforced foam did not maintain its shape when immersed in a saline solution as this promoted swelling of the gelatin; however, in the same conditions, the heat-treated gelatin-reinforced foam proved to be stable. It is concluded, therefore, that heat treatment is the key to the fabrication of stable gelatin-reinforced CO3Ap foam. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate a bone graft substitute containing carbonate apatite (CO3Ap) to analyze bone replacement and the state of bone formation in vitro and in vivo compared with autogenous bone (AB) or control. An osteoclast precursor cell line was cultured with AB or CO3Ap, and morphological analysis using scanning electron microscopy and a tartrate-resistant acid phosphatase activity assay were performed. The right maxillary first and second molars of Wistar rats were extracted and compensated by AB or CO3Ap granules. Following implantation, the bone formation state was evaluated after 3, 5, 7, 14, and 28 days of surgery by micro-computed tomography and immunohistostaining. The osteoclast-like cell morphology was typical with many cell protrusions in the AB and CO3Ap groups. Additionally, the number of osteoclast-like cells formed in the culture increased in each group; however, there was no significant difference between the AB and CO3Ap groups. Five days after tooth extraction, osteoclasts were observed near CO3Ap. The bone thickness in the CO3Ap group was significantly increased than that in the control group and the bone formation in the CO3Ap group increased by the same level as that in the AB group. CO3Ap is gradually absorbed by osteoclasts in the extraction socket and is easily replaced by alveolar bone. The process of bone replacement by osteoclasts is similar to that of autologous bone. By observing the process of bone replacement in more detail, it may be possible to gain a better understanding of the bone formation and control the amount of bone after surgery. [ABSTRACT FROM AUTHOR]

The biomineralisation of radicular dentin involves complex molecular signalling. Providing evidence of protein binding sites for calcium ions and mineral precipitation is essential for a better understanding of the remineralisation process. This study aimed to evaluate the functional relationship of metalloproteinases (MMPs) and non-collagenous proteins (NCPs) with mineral initiation and maturation during the biomineralisation of radicular dentin. A standardized demineralisation procedure was performed to radicular dentin slices. Samples were remineralised in a PBS-bioactive material system for different periods of time. Assessments of ion exchange, Raman analysis, and energy dispersive X-ray analysis (EDAX) with a scanning electron microscope (SEM) were used to evaluate the remineralisation process. Immunohistochemistry and zymography were performed to analyse NCPs and MMPs expression. SEM evaluation showed that the mineral nucleation and growth occurs, exclusively, on the demineralised radicular dentin surface. Raman analysis of remineralised dentin showed intense peaks at 955 and 1063 cm−1, which can be attributed to carbonate apatite formation. Immunohistochemistry of demineralised samples revealed the presence of DMP1-CT, mainly in intratubular dentin, whereas DSPP in intratubular and intertubular dentin. DMP1-CT and DSPP binding sites control carbonate apatite nucleation and maturation guiding the remineralisation of radicular dentin. [ABSTRACT FROM AUTHOR]

The utility of carbonate apatite (CO3Ap) as a bone substitute has been demonstrated. The feasibility of fabricating macroporous CO3Ap was evaluated through a two-step dissolution–precipitation reaction using gypsum as the precursor and spherical phenol resin as the porogen. Porogen-containing gypsum was heated to burn out the porogen and to fabricate macroporous structures. Gypsum transformed into CaCO3 upon immersion in a sodium carbonate solution, while maintaining its macroporous structure. Next, CaCO3 transformed into CO3Ap upon immersion in a Na2HPO4 solution while maintaining its macroporous structure. The utility of the macroporous CO3Ap for histologically reconstructing bone defects was evaluated in rabbit femurs. After 4 weeks, a much larger bone was formed inside the macroporous CO3Ap than that inside non-macroporous CO3Ap and macroporous hydroxyapatite (HAp). A larger amount of bone was observed inside non-macroporous CO3Ap than inside macroporous HAp. The bone defects were completely reconstructed within 12 weeks using macroporous CO3Ap. In conclusion, macroporous CO3Ap has good potential as an ideal bone substitute. [ABSTRACT FROM AUTHOR]

Three commercially available artificial bone substitutes with different compositions, hydroxyapatite (HAp; Neobone®), carbonate apatite (CO3Ap; Cytrans®), and β-tricalcium phosphate (β-TCP; Cerasorb®), were compared with respect to their physical properties and tissue response to bone, using hybrid dogs. Both Neobone® (HAp) and Cerasorb® (β-TCP) were porous, whereas Cytrans® (CO3Ap) was dense. Crystallite size and specific surface area (SSA) of Neobone® (HAp), Cytrans® (CO3Ap), and Cerasorb® (β-TCP) were 75.4 ± 0.9 nm, 30.8 ± 0.8 nm, and 78.5 ± 7.5 nm, and 0.06 m2/g, 18.2 m2/g, and 1.0 m2/g, respectively. These values are consistent with the fact that both Neobone® (HAp) and Cerasorb® (β-TCP) are sintered ceramics, whereas Cytrans® (CO3Ap) is fabricated in aqueous solution. Dissolution in pH 5.3 solution mimicking Howship's lacunae was fastest in CO3Ap (Cytrans®), whereas dissolution in pH 7.3 physiological solution was fastest in β-TCP (Cerasorb®). These results indicated that CO3Ap is stable under physiological conditions and is resorbed at Howship's lacunae. Histological evaluation using hybrid dog mandible bone defect model revealed that new bone was formed from existing bone to the center of the bone defect when reconstructed with CO3Ap (Cytrans®) at week 4. The amount of bone increased at week 12, and resorption of the CO3Ap (Cytrans®) was confirmed. β-TCP (Cerasorb®) showed limited bone formation at week 4. However, a larger amount of bone was observed at week 12. Among these three bone substitutes, CO3Ap (Cytrans®) demonstrated the highest level of new bone formation. These results indicate the possibility that bone substitutes with compositions similar to that of bone may have properties similar to those of bone. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate the feasibility of using apatite blocks fabricated by a dissolution–precipitation reaction of preset gypsum, with or without statin, to enhance bone formation during socket healing after tooth extraction. Preset gypsum blocks were immersed in a Na3PO4 aqueous solution to make hydroxyapatite (HA) low crystalline and HA containing statin (HAFS), or in a mixed solution of Na2HPO4 and NaHCO3 to make carbonate apatite (CO) and CO containing statin (COFS). The right mandibular incisors of four-week-old male Wistar rats were extracted and the sockets were filled with one of the bone substitutes or left untreated as a control (C). The animals were sacrificed at two and four weeks. Areas in the healing socket were evaluated by micro-computed tomography (micro-CT) and histological analyses. The bone volume, trabecular thickness, and trabecular separation were greatest in the COFS group, followed by the CO, HAFS, HA, and C groups. The bone mineral density of the COFS group was greater than that of the other groups when evaluated in the vertical plane. The results of this study suggest that COFS not only allowed, but also promoted, bone healing in the socket. This finding could be applicable for alveolar bone preservation after tooth extraction. [ABSTRACT FROM AUTHOR]