Octacalcium Phosphate Research Articles

Application to open wound extraction socket of new bone regenerative material

ObjectiveNew bone regenerative material of octacalcium phosphate and collagen composite (OCPcol) has exhibited excellent operability and the bone regeneration surpassed other bone substitutes. However, it has never been to elucidate the application of OCPcol for open wound extraction socket, although the previous studies suggested that OCPcol inhibited bone resorption if implanted into the closed wound extraction sockets. Therefore, the present study investigated whether OCPcol would be applicable for open wound extraction sockets. MethodsThe prepared OCPcol disks or nothing was implanted into the canine mandibular extraction sockets, and each group was closed watertight or left as an open wound. That is, the experimental groups were divided into four groups; OCPcol closed wound (OCPcol-C), OCPcol open wound (OCPcol-O), untreated closed wound (Unt-C), and untreated open wound (Unt-O). After 3 months of operation, radiomorphometric analyses was conducted by measuring alveolar cross-sectional areas of the 1/4 (Sq) and 1/2 (Sh) of the mandibular height near the alveolar apex. During the experimental periods, all animals were generally well and no eating disorders nor postoperative infections were observed including OCPcol-O. ResultsThe radiographic findings of prepared extraction sockets in each group were similarly occupied by uniform radiopaque images. However, the Sq of OCPcol-O was significantly more than other three groups, and the Sh of OCPcol-O and OCPcol-C were significantly more than those of Unt-C and Unt-O. ConclusionsThese results suggest that it would be applicable to OCPcol for extraction sockets with an open wound.

Fabrication of dicarboxylic-acid-substituted octacalcium phosphate blocks via cementing

Octacalcium phosphate (OCP) blocks with substituted dicarboxylic acid are attractive materials for new bioceramics because the substituted dicarboxylic acid enhances and regulates the biocompatibility of OCP. Therefore, OCP blocks can be model materials for biological bones and new medical combination products. However, dicarboxylic-acid-substituted OCP blocks are difficult to fabricate using conventional OCP fabrication methods such as dissolution–precipitation and simple precipitation methods because the counter cations in buffer solutions strongly inhibit dicarboxylic acid substitution into the OCP unit lattice. This study proposes a pure OCP-block fabrication method based on the cement setting of CaCO3, H3PO4, and dicarboxylic acid, which inserts dicarboxylic acid into the OCP matrix. OCP blocks with various dicarboxylic-acid substituents (succinate, thiomalate, and citrate) were obtained after optimizing the amount of CaCO3 in the mixtures. The mechanical strength of the dicarboxylic-acid-substituted OCP blocks significantly exceeded that of unsubstituted OCP.

Osteogenic differentiation and proliferation potentials of human bone marrow and umbilical cord-derived mesenchymal stem cells on the 3D-printed hydroxyapatite scaffolds

Mesenchymal stem cells (MSCs) are a promising candidate for bone repair. However, the maintenance of MSCs injected into the bone injury site remains inefficient. A potential approach is to develop a bone-liked platform that incorporates MSCs into a biocompatible 3D scaffold to facilitate bone grafting into the desired location. Bone tissue engineering is a multistep process that requires optimizing several variables, including the source of cells, osteogenic stimulation factors, and scaffold properties. This study aims to evaluate the proliferation and osteogenic differentiation potentials of MSCs cultured on 2 types of 3D-printed hydroxyapatite, including a 3D-printed HA and biomimetic calcium phosphate-coated 3D-printed HA. MSCs from bone marrow (BM-MSCs) and umbilical cord (UC-MSCs) were cultured on the 3D-printed HA and coated 3D-printed HA. Scanning electron microscopy and immunofluorescence staining were used to examine the characteristics and the attachment of MSCs to the scaffolds. Additionally, the cell proliferation was monitored, and the ability of cells to differentiate into osteoblast was assessed using alkaline phosphatase (ALP) activity and osteogenic gene expression. The BM-MSCs and UC-MSCs attached to a plastic culture plate with a spindle-shaped morphology exhibited an immunophenotype consistent with the characteristics of MSCs. Both MSC types could attach and survive on the 3D-printed HA and coated 3D-printed HA scaffolds. The MSCs cultured on these scaffolds displayed sufficient osteoblastic differentiation capacity, as evidenced by increased ALP activity and the expression of osteogenic genes and proteins compared to the control. Interestingly, MSCs grown on coated 3D-printed HA exhibited a higher ALP activity and osteogenic gene expression than those cultured on the 3D-printed HA. The finding indicated that BM-MSCs and UC-MSCs cultured on the 3D-printed HA and coated 3D-printed HA scaffolds could proliferate and differentiate into osteoblasts. Thus, the HA scaffolds could provide a suitable and favorable environment for the 3D culture of MSCs in bone tissue engineering. Additionally, biomimetic coating with octacalcium phosphate may improve the biocompatibility of the bone regeneration scaffold.

The fate of Cd during the replacement of Cd-bearing calcite by calcium phosphate minerals

Carbonate-bound speciation is a critical sink of potentially toxic elements (PTEs) like cadmium (Cd) in soil and sediment. In a phosphate-rich environment, carbonate minerals could be replaced by phosphate minerals such as dicalcium phosphate dihydrate (DCPD, also known as brushite), octacalcium phosphate (OCP), and hydroxylapatite (HAP). Currently, it is unclear the migration and fate of PTEs during the replacement of PTEs-bearing carbonates by HAP and related intermediate minerals. Therefore, we synthesized Cd-bearing calcite by the coprecipitation method and converted it to DCPD, OCP, and HAP to investigate the redistribution and fate of Cd. The results showed that Cd incorporation in calcite significantly inhibited their replacement by DCPD and OCP, respectively. 1.26% of Cd in calcite was released into the solution when DCPD replaced calcite, and subsequently, most of the released Cd was recaptured by OCP. Significantly, the released Cd was below 0.05‰ when all the solid converted to HAP. These results suggested that with the application of phosphate fertilizer in alkaline soil, the secondary calcium phosphate minerals could control the environmental behavior of Cd.

Kappa-carrageenan-Functionalization of octacalcium phosphate-coated titanium Discs enhances pre-osteoblast behavior and osteogenic differentiation.

Bioactive coatings are promising for improving osseointegration and the long-term success of titanium dental or orthopaedic implants. Biomimetic octacalcium phosphate (OCP) coating can be used as a carrier for osteoinductive agents. κ-Carrageenan, a highly hydrophilic and biocompatible seaweed-derived sulfated-polysaccharide, promotes pre-osteoblast activity required for bone regeneration. Whether κ-carrageenan can functionalize OCP-coating to enhance osseointegration of titanium implants is unclear. This study aimed to analyze carrageenan-functionalized biomimetic OCP-coated titanium structure, and effects of carrageenan functionalization on pre-osteoblast behavior and osteogenic differentiation. Titanium discs were coated with OCP/κ-carrageenan at 0.125-2mg/ml OCP solution, and physicochemical and biological properties were investigated. κ-Carrageenan (2mg/ml) in the OCP coating of titanium discs decreased the pore size in the sheet-like OCP crystal by 41.32%. None of the κ-carrageenan concentrations tested in the OCP-coating did affect hydrophilicity. However, κ-carrageenan (2mg/ml) increased (1.26-fold) MC3T3-E1 pre-osteoblast spreading at 1h i.e., κ-Carrageenan in the OCP-coating increased pre-osteoblast proliferation (max. 1.92-fold at 2mg/ml, day 1), metabolic activity (max. 1.50-fold at 2mg/ml, day 3), and alkaline phosphatase protein (max. 4.21-fold at 2mg/ml, day 3), as well as matrix mineralization (max. 5.45-fold at 2mg/ml, day 21). κ-Carrageenan (2mg/ml) in the OCP-coating increased gene expression of Mepe (4.93-fold) at day 14, and Runx2 (2.94-fold), Opn (3.59-fold), Fgf2 (3.47-fold), Ocn (3.88-fold), and Dmp1 (4.59-fold) at day 21 in pre-osteoblasts. In conclusion, κ-carrageenan modified the morphology and microstructure of OCP-coating on titanium discs, and enhanced pre-osteoblast metabolic activity, proliferation, and osteogenic differentiation. This suggests that κ-carrageenan-functionalized OCP coating may be promising for in vivo improvement of titanium implant osseointegration.

Bio-Activation of HA/β-TCP Porous Scaffolds by High-Pressure CO2 Surface Remodeling: A Novel "Coating-from" Approach.

Biphasic macroporous Hydroxyapatite/β-Tricalcium Phosphate (HA/β-TCP) scaffolds (BCPs) are widely used for bone repair. However, the high-temperature HA and β-TCP phases exhibit limited bioactivity (low solubility of HA, restricted surface area, low ion release). Strategies were developed to coat such BCPs with biomimetic apatite to enhance bioactivity. However, this can be associated with poor adhesion, and metastable solutions may prove difficult to handle at the industrial scale. Alternative strategies are thus desirable to generate a highly bioactive surface on commercial BCPs. In this work, we developed an innovative “coating from” approach for BCP surface remodeling via hydrothermal treatment under supercritical CO2, used as a reversible pH modifier and with industrial scalability. Based on a set of complementary tools including FEG-SEM, solid state NMR and ion exchange tests, we demonstrate the remodeling of macroporous BCP surface with the occurrence of dissolution–reprecipitation phenomena involving biomimetic CaP phases. The newly precipitated compounds are identified as bone-like nanocrystalline apatite and octacalcium phosphate (OCP), both known for their high bioactivity character, favoring bone healing. We also explored the effects of key process parameters, and showed the possibility to dope the remodeled BCPs with antibacterial Cu2+ ions to convey additional functionality to the scaffolds, which was confirmed by in vitro tests. This new process could enhance the bioactivity of commercial BCP scaffolds via a simple and biocompatible approach.

Acceleration of bone formation by octacalcium phosphate composite in a rat tibia critical-sized defect.

BackgroundThe osteogenic capabilities and biodegradability of octacalcium phosphate (OCP) composites make them unique. Despite the excellent characteristics of OCP, their use is limited due to handling difficulties. In this study, we aimed to evaluate and compare three types of OCPs (cemented OCP (C-OCP), C-OCP with collagen (OCP/Col), and synthetic OCP (S-OCP) with alginate (OCP/Alg)) versus commercially available β-tricalcium phosphate (β-TCP) regarding their potential to accelerate bone formation in defective rat tibias.MethodsThe specimens with OCP composite were manufactured into 5 ​mm cubes and inserted into the segmental defects of rat tibias fixed with an external fixator. In addition, 3 ​mm-hole defects in rat tibias were evaluated to compare the graft material properties in different clinical situations. Serial X-ray studies were evaluated weekly and the tibias were harvested at postoperative 6 weeks or 8 weeks for radiologic evaluation. Histological and histomorphometric analyses were performed to evaluate the acceleration of bone formation.ResultsIn the critical-defect model, OCP/Alg showed bone bridges between segmentally resected bone ends that were comparable to those of β-TCP. However, differences were observed in the residual graft materials. Most β-TCP was maintained until 8 weeks postoperatively; however, OCP/Alg was more biodegradable. In addition calcification in the β-TCP occurred at the directly contacted area between graft particles and bony ingrowth was observed in the region adjacent resected surface of tibia. In contrast, no direct bony ingrowth was observed in OCP-based materials, but osteogenesis induced from resected surface of tibia was more active. In the hole-defect model, OCP/Col accelerated bone formation. β-TCP and OCP/Alg showed similar patterns with relatively higher biodegradability. In histology, among the OCP-based materials, directly contacted new bone was formed only in OCP/Alg group. The new bone formation in the periphery area of graft materials was much more active in the OCP-based materials, and the newly formed bone showed a thicker trabecular and more mature appearance than the β-TCP group.ConclusionsIn this study, OCP/Alg was equivalent to β-TCP in the acceleration of bone formation with better biodegradability appropriate for clinical situations in different circumstances. Our OCP/Col composite showed fast degradation, which makes it unsuitable for use in mechanical stress conditions in clinical orthopedic settings.The Translational Potential of this ArticleIn our research, we compared our various manufactured OCP composites to commercially available β-TCP in critical-defect rat tibia model. OCP/Col showed acceleration in hole-defect model as previous studies in dental field but in our critical-sized defect model it resorbed fast without acceleration of bony union. OCP/Alg showed matched results compared to β-TCP and relatively fast resorption so we showed market value in special clinical indication depending on treatment strategy. This is the first OCP composite study in orthopaedics with animal critical-sized tibia bone study and further study should be considered for clinical application based on this study.

Calcium phosphate cements comprising spherical porous calcium phosphate granules: synthesis, structure, and properties

ABSTRACT Calcium phosphate cements (CPCs) are used as artificial bone materials. The bone regeneration ability of CPCs can be improved by controlling their composition, porosity, and pore size. This study aims to design novel CPCs with high bone regeneration ability by controlling their microstructure. CPCs with macropores and micropores were prepared by incorporating spherical porous calcium phosphate granules composed of rod-shaped, calcium-deficient hydroxyapatite (CDHA) or plate-shaped octacalcium phosphate (OCP) particles. The granules were mixed with a binder (cement powder) composed primarily of α-tricalcium phosphate. The structure, morphology, compressive strength, porosity, specific surface area, pore size distribution, dissolution characteristics, and effects on cell viabilities were studied for the synthesized samples. The CPCs composed of porous granules had high porosity (~80%) and both macropores and micropores, which are expected to contribute to bone regeneration. The CPCs composed of porous granules showed a smaller specific surface area but a larger dissolution rate than the granule-free samples. The CPC composed of OCP granules showed a higher dissolution rate than the CPCs containing CDHA granules. In the cell culture experiments, the preosteoblasts proliferated on the CPCs, indicating that these CPCs could function as scaffolds for bone regeneration.

Synchrotron X-ray diffraction computed tomography to non-destructively study inorganic treatments for stone conservation

SummaryThe characterization of consolidating products formed by conservation treatments within Cultural Heritage (CH) materials is a burning issue and an analytical challenge, as non-destructive approaches, phase analysis, and volume distribution analysis are simultaneously required. This paper proposes the use of synchrotron X-ray diffraction computed tomography (XRDCT) to non-destructively study diammonium hydrogen phosphate (DAP) consolidating treatments for stone conservation. The mineralogical composition and localization of crystalline phases formed in a complex mixture have been explored and spatially resolved. The coexistence of hydroxyapatite and octacalcium phosphate has been finally demonstrated. The image analysis highlights the 3D distribution of calcium phosphates, their arrangement in a binding network down to the voxel scale, and their consolidating action. Above all, this study demonstrates the feasibility and high potential of XRDCT to investigate the interactions of conservation treatments with CH stone materials, and opens new analytical perspectives for XRDCT in conservation science and materials science.

Formation of octacalcium phosphate in the interaction of calcium carbonate and monocalcium phosphate monohydrate under galvanostatic conditions

The calcium phosphate composite octacalcium phosphate / calcite was obtained at pH 5–7 from the CaCO3/Ca(H2PO4)2 aqueous suspension in a galvanostatic mode at a current density of 20 mA/cm2 for 20 min. Drying at 80 °C without the precipitate maturation stage led to a powder formation consisting of brushite, calcite and a small amount of octacalcium phosphate. Prolonged maturation in air for 2 months led to the hydrolytic transformation of brushite into octacalcium phosphate stabilized by calcite. The use of electric current made it possible to increase the amount of octacalcium phosphate in the composite powder with the morphology of lamellar rosettes. Calcination at 800 °C of the composite powders led to the formation of α/β-tricalcium phosphate, β-calcium pyrophosphate, hydroxyapatite, and calcium oxide.

Sialolithiasis: mineralogical composition, crystalline structure, calculus site, and epidemiological features

The purpose of this paper was to describe the characteristics of salivary calculi and their relationship to epidemiological factors, through a cross-sectional study. We analysed 100 calculi obtained in 2017–2021. Patient data including age, time since onset of symptoms, gland involved, and site of location in the salivary system were studied. The calculi were studied to determine their morphological features using scanning electron microscopy and energy dispersive plain radiographic analysis. Most of the calculi had formed in the submandibular gland (SG) (82%). The mean age of patients at onset was 45.83 years; patients presenting parotid gland (PG) stones were somewhat older (p = 0.031). The mean time since the onset of symptoms was longer in PG calculi (p = 0.038). The most common lithiasis site was the main duct (74%), followed by the hilum (22%). Hilar stones were the largest (p < 0.05) and heaviest (p = 0.028). Octacalcium phosphate (OCP) was the most common crystalline phase (Cp) founded, followed by hydroxyapatite (HA) and whitlockite (WH). Specifically, OCP had a higher presence in PG calculi (p = 0.029) and WH was the most common phase in SG calculi (p = 0.017). The most prevalent site of lithiasis was the main duct, and the largest and heaviest calculi were found in the SG. PG stones were associated with a longer history of symptoms and older age. OCP was the most frequent Cp of the calculi studied, and the main Cp in PG stones. WH was the predominant Cp in SG stones. The Cp of the calculi was not influenced by location, patient age, or time of symptoms.

Hierarchy of Bioapatites.

Apatites are one of the most intensively studied materials for possible biomedical applications. New perspectives of possible application of apatites correspond with the development of nanomaterials and nanocompounds. Here, an effort to systematize different kinds of human bioapatites forming bones, dentin, and enamel was undertaken. The precursors of bioapatites and hydroxyapatite were also considered. The rigorous consideration of compositions and stoichiometry of bioapatites allowed us to establish an order in their mutual sequence. The chemical reactions describing potential transformations of biomaterials from octacalcium phosphate into hydroxyapatite via all intermediate stages were postulated. Regardless of whether the reactions occur in reality, all apatite biomaterials behave as if they participate in them. To conserve the charge, additional free charges were introduced, with an assumed meaning to be joined with the defects. The distribution of defects was coupled with the values of crystallographic parameters “a” and “c”. The energetic balances of bioapatite transformations were calculated. The apatite biomaterials are surprisingly regular structures with non-integer stoichiometric coefficients. The results presented here will be helpful for the further design and development of nanomaterials.

Ionic insertion fabrication of novel octacalcium phosphate block materials exhibiting antibacterial ability and biocompatibility

As the population ages worldwide, the importance of maintaining the metabolism of the skeletal system becomes increasingly important. The skeleton is the core of the locomotor and oral structure. Moreover, infection control is an essential part of orthopedic and oral surgery. This paper investigates new bone substitutes fabricated by the ionic substitution method leading to octacalcium phosphate (OCP) with excellent contact antibacterial ability, biocompatibility, and bone replacement. To improve the functionality of OCP-based materials as a bone substitute, we introduce a novel OCP block fabrication method based on the dissolution–precipitation method, study the factors that induce OCP in solution, and propose a robust method for cation substitution in the OCP unit lattice named the ionic insertion method. We then fabricate Ag-substituted OCP (OCP–Ag) blocks using this method and evaluate their antibacterial activity in vivo. These techniques will contribute to new-generation medical services and improve the quality of life of individuals requiring implants.

Lanthanum doped octacalcium phosphate/polylactic acid scaffold fabricated by 3D printing for bone tissue engineering

Lanthanum (La) has tremendous potential in the treatment and prevention of bone diseases especially osteoporosis and metabolic disorders. However, controlling its distribution and keeping the release of La3+ ions sustained and steady in the body is still a big challenge. In this study, we prepared La-OCP powders via co-precipitation method, and further prepared La-OCP/PLA porous scaffolds by 3D printing. La3+ was successfully introduced into the OCP crystal structure and substituted Ca2+ at the Ca-5 and Ca-8 sites. In particular, some La3+ ions were deposited on the crystal surface in the form of nanoparticles. Both octacalcium phosphate (OCP, Ca8H2(PO4)6·5H2O) crystals and nanoparticles played as the carriers for La3+ ions. The La-OCP/PLA scaffolds displayed obvious mineralization effects and sustained release of La3+. The scaffolds contained a uniform structure with rough micro surface topography which acted as a suitable pathway for BMSCs cells to adhere, grow and proliferation. At a certain La3+ concentration, the extracts from La-OCP/PLA scaffolds increased the expression of osteogenesis-related genes, thus promoting the osteogenic differentiation of BMSCs. Moreover, the extracts regulated the immune responses. The experiment in vivo proved that La-OCP/PLA porous scaffolds were safe and could enhance bone defect regeneration in vivo. These findings suggest that 3D printed La-OCP/PLA porous scaffolds have promising potentials in bone tissue engineering.

Review of Octacalcium Phosphate Materials for Bone Tissue Engineering

Review of Octacalcium Phosphate Materials for Bone Tissue Engineering

A new multiphase calcium phosphate graft material improves bone healing-An in vitro and in vivo analysis.

This study aims to evaluate the potential of a novel biomaterial synthesized from amorphous calcium phosphate (ACP), octacalcium phosphate (OCP), and hydroxyapatite (HA) to repair critical-sized defects (CSD) in rabbit calvaria. In vitro analyses of cell viability, cell proliferation, formation of mineral nodules, and cell differentiation using qPCR were performed for comparing experimental calcium phosphate (ECP), deproteinized bovine bone (DBB), and beta-tricalcium phosphate (β-TCP). Bilateral CSDs were created in 45 rabbit calvaria. Six groups were evaluated: ECP, ECP + fibrin sealant (ECP + S), coagulum, autogenous bone, DBB, and β-TCP. Euthanasia was performed at 2, 4, and 8 weeks, followed by micro-computed tomography and histological and immunohistochemical analyses. Results from in vitro analyses revealed similar biocompatibility for all tested materials and a tendency for higher gene expression of some bone markers in the ECP group than in β-TCP and DBB groups at 7 days. In contrast to that in DBB and β-TCP groups, ECP displayed growing bone volume over total volume percentage (BV/TV%) with time in vivo. Histological analysis revealed a greater number of giant cells and reduced size of grafted particles in ECP during all periods of analysis. RUNX-2 expression was statistically lower in ECP than DBB at 2 and 4 weeks. Despite no statistical significance, ECP presented the highest absolute values for ALP-expression at 2, 4, and 8 weeks compared with other groups. Together, our findings indicate that a combination of the ACP, OCP, and HA phases into ECP is beneficial and promising for bone regeneration.

In Situ Observation of Dicalcium Phosphate Monohydrate Formation and Phase Transformation.

Calcium orthophosphates (CaPs), as important minerals in biomineralization and biomedicine, have attracted wide attention. Dicalcium phosphate monohydrate (DCPM, CaHPO4·H2O), the recently discovered crystalline CaP phase, has a higher metastability than dihydrate (DCPD, CaHPO4·2H2O) and anhydrate (DCPA, CaHPO4), which may lead to many potential applications in functional biomaterial development. However, the preparation of large-sized DCPM and the underlying mechanisms of its formation and phase evolution remain unclear. Herein, for the first time, we propose a method to prepare micrometer-sized DCPM under an acidic water-methanol mixture and using in situ time-resolved atomic force microscopy further explore its crystallization via dissolution of an acidic amorphous calcium phosphate. In support of the potential role of DCPM as the biomaterial, we demonstrate that DCPM can quickly evolve into more stable octacalcium phosphate in a near-physiological solution. This work provides a mechanistic understanding of the formation and phase transformation of DCPM, which may serve as a basis for subsequent synthesis and application of DCPM as functional biomaterials.

Formation and corrosion behavior of calcium phosphate coating layers on ZK60 alloy coated at various pH conditions by chemical conversion method

The formation and corrosion protectiveness of calcium phosphate coating layers depend on the coating conditions and the type of magnesium (Mg) substrate. Therefore, this study aimed to investigate the formation of the calcium phosphate coating layers on Mg-6mass% Zn-0.5mass%Zr (ZK60) alloy over a wide pH range of pH 6.5 to 10.2. Immersion tests with Mg2+ ion quantification were performed to study the degradation behavior of ZK60 coated with different types of calcium phosphate. It was found that the morphology and types of the calcium phosphate coating layers were controlled by pH conditions. At pH 6.5, an octacalcium phosphate (OCP) single phase layer was formed. At pH 7.0, an OCP + hydroxyapatite (HAp) mixture layer was formed. A HAp single layer and a HAp layer with an intermediate Mg(OH)2 layer were formed at pH 7.8 and 10.2, respectively. The coating layers provided good corrosion protection but at different levels. The specimen coated at pH 7.8 possessed the best corrosion resistance. On this specimen, biocompatible hydroxyapatite (HAp) was deposited as a corrosion product after the immersion. The results suggest that the specimen coated at pH 7.8 serves as a suitable orthopedic implant.

Fabrication of Octacalcium Phosphate Block through the Reaction between CaCO3 Powder and Phosphate Acid

Octacalcium phosphate (OCP) demonstrates excellent biocompatibility but has low formability. In this study, we introduced a new fabrication method for OCP block, in which the reaction between CaCO3 powder and H3PO4 chemical reaction is used. Since this reaction could proceed at near body temperature, the OCP blocks could be readily formed, which had enough mechanical strength for bone substitute.

Preparation of Calcium Phosphate Compounds on Zirconia Surfaces for Dental Implant Applications.

Titanium is widely used in medical implants despite the release of heavy metal ions over long-term use. Zirconia is very close to the color of teeth; however, its biological inertness hinders bonding with bone tissue. Alkaline treatment and coatings of calcium phosphate can be used to enhance bone regeneration adjacent to dental implants. This study examined the effects of alkaline treatment, calcium phosphate coatings, and sintering, on the physical properties of implant material. Our analysis confirmed that the calcium phosphate species were octacalcium phosphate (OCP). The sintering of calcium phosphate was shown to create B-type HAP, which is highly conducive toward the differentiation of mesenchymal stem cells (MSCs) into osteoblasts for the facilitation of bone integration. Conclusions: This study demonstrated the room-temperature fabrication of dental implants with superhydrophilic surfaces to enhance biocompatibility.