TCP Content Research Articles

Magnesium-Substituted Brushite Cement: Physical and Mechanical Properties

Brushite cements (BrCs) are calcium phosphate-based materials that are being widely used in hard tissue engineering applications due to their osteoconductivity, injectability, and bioresorbability. Therefore, the goal was to evaluate the effects of Mg concentration on the phase composition, setting time, and strength of BrC. Mg, which plays a vital role in bodily functions and bone health, was added to BrC at concentrations of 0.25, 0.50, 1.00, 1.50, 2.00, and 2.50 wt.%. The results showed that Mg stabilizes the TCP structure and increases the TCP content in final BrC. The initial and final setting times of BrCs increase with higher concentrations of Mg. Although 0.25 wt.% Mg did not change the setting of BrCs significantly, a higher concentration of 1.00 wt.% increased the initial setting time from 4.87 ± 0.38 min to 15.14 ± 0.88 min. Cements with Mg concentrations of 1.5 wt.% and above did not set after 4 h. Mg addition up to 0.5 wt.% did not change the compressive strength; however, higher concentrations decreased it significantly and 2.5 Mg-BrC had the lowest strength of 0.45 ± 0.09 MPs. Together, our results show that Mg can be added up to 1.00 wt.% without any adverse effect on the physical and mechanical properties of BrC.

Temperature-dependent and duration-dependent effect on the growth behavior of CVD aluminide coating on K452 superalloy

Aluminide coatings on the K452 alloys were fabricated in this study by chemical vapor deposition (CVD) under various deposition temperature and duration aiming to investigate the growth behavior of aluminide coating. The microstructure and phase evolution of aluminide coating were discussed in detail. Results showed that the outer layer (OL) consisting of β-NiAl, and the inter-diffusion layer (IDL) comprised of carbides and topologically close packed phases TCP (Cr3(Ni, Co)2) were formed in all specimens. In addition, another whisker precipitation phase can be found in aluminized specimens deposited at 850 °C, 900 °C and 950 °C, and finally transformed into Cr3(Ni, Co)2 phase by further promoting the deposition temperature. As for the specimens deposited for various duration, the content of TCP in the specimens deposited at 1050 °C showed a decreasing trend with the increase of the deposition duration, and the opposite for carbides. Based on these results, the growth behavior of CVD aluminide coating on K452 superalloy was proposed comprehensively. The results of this study can provide a guidance for preparation of high-performance CVD aluminide coating on K452 superalloys.

Dynamic degradation patterns of porous polycaprolactone/β-tricalcium phosphate composites orchestrate macrophage responses and immunoregulatory bone regeneration.

Biodegradable polycaprolactone/β-tricalcium phosphate (PT) composites are desirable candidates for bone tissue engineering applications. A higher β-tricalcium phosphate (TCP) ceramic content improves the mechanical, hydrophilic and osteogenic properties of PT scaffolds in vitro. Using a dynamic degradation reactor, we established a steady in vitro degradation model to investigate the changes in the physio-chemical and biological properties of PT scaffolds during degradation.PT46 and PT37 scaffolds underwent degradation more rapidly than PT scaffolds with lower TCP contents. In vivo studies revealed the rapid degradation of PT (PT46 and PT37) scaffolds disturbed macrophage responses and lead to bone healing failure. Macrophage co-culture assays and a subcutaneous implantation model indicated that the scaffold degradation process dynamically affected macrophage responses, especially polarization. RNA-Seq analysis indicated phagocytosis of the degradation products of PT37 scaffolds induces oxidative stress and inflammatory M1 polarization in macrophages. Overall, this study reveals that the dynamic patterns of biodegradation of degradable bone scaffolds highly orchestrate immune responses and thus determine the success of bone regeneration. Therefore, through evaluation of the biological effects of biomaterials during the entire process of degradation on immune responses and bone regeneration are necessary in order to develop more promising biomaterials for bone regeneration.

Optimization of conventional solid-liquid extraction and microwave-assisted extraction of polyphenols and antioxidant compounds of blueberry (Vaccinium corymbosum) pomace through response surface methodology

BACKGROUND: Blueberries contain large amounts of phenolic compounds as well as a higher concentration of anthocyanins than other berries. The peel of these fruits contains most of the anthocyanins and therefore pomace is left with the largest quantity of valuable phenolic compounds. Extraction is the most critical step to obtain such compounds. OBJECTIVE: This study aims to optimize the extraction of polyphenols and antioxidant compounds from blueberry pomace by solid-liquid extraction (SLE) and microwave-assisted extraction (MAE). METHODS: A Pareto chart was used to confirm the factor with the highest impact, response surface for analyzing the effect of extraction conditions on total phenol content (TPC) (through Folin-Ciocalteu), total anthocyanin content (TAC) (through differential pH), antioxidant capacity (AC) (through DPPH assay) and the Box-Behnken matrix to determine the optimal conditions for marc extraction with each method. RESULTS: Ethanol concentration is an impact factor for both methods, as well as irradiation method, radiation power for MAE and temperature for SLE. Regarding SLE and MAE extraction, under optimal conditions, a TCP content of 335.95 and 426.19 (mg GAE/100 g), TAC 272.69 and 389.64 (mg Cyn-3-glu/100 g), and CA 528.96 and 654.11 (mg TE/100 g) was obtained, respectively. CONCLUSIONS: The performance of phenolic compound extraction via MAE method is better than that of SLE.

Tricalcium Phosphate Sol-Incorporated Poly(ε-caprolactone) Membrane with Improved Mechanical and Osteoinductive Activity as an Artificial Periosteum.

The periosteum plays a very important role in bone remodeling and regeneration due to its excellent osteogenic ability. However, in bone defects, the periosteum is inevitably damaged, has poor self-repair ability, and requires artificial materials as a substitute. This study is aimed to fabricate a highly bioactive poly(ε-caprolactone)/tricalcium phosphate sol (PCL/TCP sol) hybrid membrane as an artificial periosteum covering the surface of the bone defect to enhance bone regeneration. Three kinds of PCL membranes with different TCP contents were prepared and marked as P20T1 (4.8 wt %), P10T1 (9.1 wt %), and P5T1 (16.7 wt %). The physicochemical properties' evaluation confirmed that TCP sol was homogeneously dispersed in the PCL nanofibers. Compared with P5T1, samples P10T1 and P20T1 had enhanced the mechanical properties and a moderately hydrophilic surface (67.3 ± 2.4° for P20T1 and 48.9 ± 4.1° for P10T1). The biomineralization of hybrid membranes was significantly improved compared to the PCL membrane. Moreover, hybrid membranes significantly upregulated the rat bone marrow mesenchymal stem cells' (rBMSCs) response (proliferation and osteogenic differentiation) to them, and P10T1 showed better surface properties (hydrophilicity, bioactivity, and biomineralization) than P20T1. Thus, sample P10T1 with the best properties in this study has great potential as an artificial periosteum to accelerate bone regeneration.

Synthesis of Hydroxyapatite, β-Tricalcium Phosphate and Biphasic Calcium Phosphate Particles to Act as Local Delivery Carriers of Curcumin: Loading, Release and In Vitro Studies.

The successful synthesis of hydroxyapatite (HA), β-Tricalcium phosphate (β-TCP) and two biphasic mixtures (BCPs) of the two was performed by means of wet precipitation. The resulting crystals were characterized and the BCP composition was analyzed and identified as 13% HA—87% TCP and 41% HA—59% TCP. All samples were treated with curcumin solutions, and the degree of curcumin loading and release was found to be proportional to the TCP content of the ceramic. No further cytotoxicity was observed upon MG-63 treatment with the curcumin-loaded ceramics. Finally, the alkaline phosphatase activity of the cells was found to increase with increasing content of TCP, which provides an encouraging proof of concept for the use of curcumin-loaded synthetic biomaterials in bone remodeling.

Evaluation of a new biphasic calcium phosphate for maxillary sinus floor elevation: Micro‐CT and histomorphometrical analyses

ObjectivesSynthetic biphasic calcium phosphate (BCP) with a hydroxyapatite/ß‐tricalcium phosphate (HA/ß‐TCP) ratio of 60/40 (BCP60/40) is successfully used as alternative for autologous bone in patients undergoing maxillary sinus floor elevation (MSFE) for dental implant placement. A high percentage of HA in BCP60/40 may hamper efficient scaffold remodeling. Osteogenesis and neovascularization are pivotal in effective bone regeneration. We aimed to investigate whether differences exist in osteogenic and/or vasculogenic potential of BCP60/40 and BCP20/80 in patients undergoing MSFE.Materials and methodsTwenty patients undergoing MSFE were treated with BCP60/40 (n = 10) or BCP20/80 (n = 10). Bone and graft volumes were determined by micro‐computed tomography and histomorphometrical analysis of biopsies of the augmented region. Osteoid volumes, number of osteoclasts, and blood vessels were determined by histomorphometrical analysis. The biopsies were taken 6.5 months (26 weeks) postoperatively prior to dental implant placement.ResultsBone and osteoid volumes were 9.7% and 0.8% higher at the most cranial side of the BCP20/80 biopsies compared to the BCP60/40 biopsies. Graft volumes, number of osteoclasts, and blood vessels were similar in both groups.Conclusions BCP20/80 showed enhanced osteogenic potential in patients undergoing MSFE compared to BCP60/40, due to either a faster bone remodeling rate or an earlier start of bone formation in BCP20/80‐treated patients, suggesting that a higher TCP content positively contributes to the bone remodeling rate. Therefore, BCP20/80 might perform better, at least in the short term, as a scaffold for bone augmentation in the MSFE model than BCP60/40 as more bone is formed, and more osteoid is deposited at the cranial side in BCP20/80‐treated patients compared to BCP60/40‐treated patients. However, catch‐up of BCP60/40 in the long term cannot be ruled out.

Microstructure and Property Calculation of Three Typical Second Generation Single Crystal Superalloys

To theoretically evaluate three widely used second generation single crystal superalloys-PWA1484, ReneN5 and DD6, the alloy densities, phase graphs, TCP contents, d-electron energy, and creep rupture lives were calculated, and the calculation results were analyzed combined with actual data. Results showed that among the three alloys, PWA1484 had the greatest density, secondly was DD6, and ReneN5’s density was the lowest. The PWA1484 alloy was most likely to precipitate TCP due to its highest d-orbital energy level; the ReneN5 alloy had a medium d-orbital energy level, but its high Cr content induced it to precipitate the most TCP types; the DD6 alloy had the least chance to precipitate TCP phases because of its lowest d-orbital energy level as well as lowest Cr content. It is concluded that thermodynamic calculation had the ability to simulate TCP types and TCP content at steady states, while d-orbital energy concept was capable of exhibiting the alloys in sequence of TCP precipitation potential. Mere thermodynamic calculation will lead to comparatively conservative results, including more TCP types, higher TCP contents and lower rupture lives. Analyzing the thermodynamic and d-orbital energy calculations comprehensively, it can be considered that the DD6 alloy has the most stable microstructure among the three single crystal superalloys.

Preparation, characterization and in vitro dissolution behavior of porous biphasic α/β-tricalcium phosphate bioceramics

The ideal bone tissue engineering scaffolds are long-cherished with the properties of interconnected macroporous structures, adjustable degradation and excellent biocompatibility. Here, a series of porous α/β-tricalcium phosphate (α/β-TCP) biphasic bioceramics with different phase ratios of α-TCP and β-TCP were successfully synthesized by heating an amorphous calcium phosphate precursor. The chemical and morphological characterization showed that α- and β-TCP phases co-existed in the α/β-TCP bioceramics and they had interconnected pore structures with size between 200 and 500μm. The in vitro dissolution behavior and bioactivity of the dual α/β-TCP were also probed in static and dynamic SBF for the first time. The results revealed that α/β-TCP scaffolds had good in vitro bioactivity, as the formation of bone-like apatite layers was induced on the scaffolds after mineralization in SBF. Moreover, dissolution rate of α/β-TCP bioceramics in dynamic environment was higher than that under static condition. Compared with monophasic TCP ceramics, these porous α/β-TCP bioceramics displayed a tailored dissolution rate proportionate to the TCP content (α and β) in the materials. Further, the degradation profile of porous α/β-TCP was well-described by Avrami equation. The porous dual α/β-TCP bioceramics with controllable degradation behavior hold great potential to be applied in bone tissue engineering as bone substitutes.

Effects of MgO addition on sintering of calcium phosphate ceramics and composites

Bioactive ceramics attracts much attention as materials for bone implants, because of their high biocompatibility. For example, hydroxyapatite (HA) has bone-bonding ability through a bone-like apatite layer in body environment and β-tricalcium phosphate (β-TCP) has a high bioresorbability in body environment. In addition, HA/β-TCP composites has the characteristics of both HA and TCP. However, it is difficult to sinter the composite, so that MgO has been used as a sintering agent. In the present study, effects of MgO addition on sintering calcium phosphate ceramics and composites were investigated. In order to evaluate the effect of MgO on the composites, HA, HA/β-TCP(30wt%), and HA/β-TCP(50wt%) with 1wt% MgO were prepared and characterized. To clarify the role of MgO on sintering of calcium phosphate ceramics, HA, β-TCP, and α-TCP with different TCP content (0, 1, 2, 3, 4, and 5 wt%) were also prepared. The results suggest that MgO addition densified HA/β-TCP composites and gave higher strength composites. The results of monolithic calcium phosphate ceramics indicated MgO addition was effective on β-TCP and α-TCP, not on HA. The maximum content of Ca atom in β-TCP displaced with Mg atoms in MgO might be 24 atm%.

Preparation of tricalcium phosphate–calcium alginate composite flat sheet membranes and their application for protein release

Tricalcium phosphate–calcium alginate (TCP–CA) composite flat sheet membranes with the thickness of 150–200 μm were prepared by Ca2+ crosslinking of TCP and sodium alginate (SA) aqueous solution. The composite flat sheet membranes were characterized by SEM, FTIR, DSC and BET method. The mechanical properties of the membranes were tested with a tensile testing machine in wet form. Hemoglobin (HB) was immobilized in the following four matrices (1) HB was adsorbed onto the TCP powders directly, (2) HB and SA dissolved together, and then crosslinked by CaCl2, (3) HB was pre‐adsorbed onto TCP powders, and then mixed with SA aqueous solution, finally crosslinked by CaCl2, (4) HB and TCP powders were individually dispersed in the SA aqueous solution and then crosslinked by CaCl2. The release behaviors of the four materials were investigated in phosphate buffer (pH = 6.86), Tris‐HCl solution (pH = 7.4) and NaCl solution (0.9 wt%). SEM observation showed that the TCP particles were well embedded and homogeneously distributed in the alginate matrix. DSC and FTIR indicated that there were additional interactions between the TCP and the polymer. TCP can improve the mechanical properties of CA membranes and the swelling ratio of TCP–CA membrane in NaCl solution decreased with the increase of TCP content. The sustained release behaviors of matrix 3 were shown in PBS, Tris‐HCl and NaCl solutions. POLYM. COMPOS., 36:1899–1906, 2015. © 2014 Society of Plastics Engineers

Effect of Hydrolysis on Mechanical Behavior of Bioabsorbable Composites

In this study, effect of hydrolysis in simulated body environment on mechanical behavior oftricalcium phosphate (TCP)/Poly(L-lactic acid) (PLLA) composites were analytically characterized.In order to predict stress-strain behavior after hydrolysis, damage micromechanical analysis proposedby the authors were utilized. In this model, nonlinear behavior in stress strain relationship weresimulated considering interfacial debonding between TCP particle and PLLA matrix. For the purposeof deciding the interfacial strength, such as critical energy release rate, curve fitting was conducted onthe result of the composites with 15wt% TCP content. Theoretical results on 5wt% and 10wt%composites using the interfacial strength obtained were in good agreement with experimental results.This result indicated that interfacial strength was independent from TCP fraction.

Effect of in vitro hydrolysis on the compressive behavior and strain rates dependence of tricalcium phosphate/poly(L-lactic acid) composites

Bioactive ceramics/bioresorbable plastic composites have been expected as materials for the fracture fixations which have more biocompatibility than monolithic bioresorbable plastics. In this study, effects of strain rate on the mechanical properties of poly(L-lactic acid) (PLLA) and tricalcium phosphate/Poly(L-lactic acid) (TCP/PLLA) composites specimens were investigated experimentally. The TCP/PLLA composites containing three different TCP contents (5, 10 and 15 wt.%) were prepared by injection molding. The fabricated specimens were then immersed in the simulated body environment, such as phosphate buffered solution (pH = 7.4), to investigate effects of hydrolysis on the mechanical properties. In order to characterize the mechanical properties, compressive tests were performed at the strain rates ranging from 10−3 to 10−1/s. Initial molecular weights (M w) of non-annealing PLLA and TCP/PLLA composites were approximately 173,000 and 154,000. After 24 weeks immersion, M w of 15 wt.% decreased to 91,000. In the results of these tests, TCP/PLLA composites showed that their Young’s modulus has no dependence on the strain rate and their compressive strength increased with increasing strain rates. After 16 weeks immersion, compressive strength of 15 wt.% composites decreased slightly at a strain rate of 10−1/s. After 24 weeks immersion, compressive strength of 5, 10, and 15 wt.% composites decreased.

Optimization of TCP/HAP ratio for better properties of calcium phosphate scaffold via selective laser sintering

Calcium phosphate ceramics are considered as the most promising materials for bone tissue engineering due to their excellent biocompatibility and bioactivity. In the paper, porous calcium phosphate scaffolds were prepared via selective laser sintering with various weight ratios of TCP/HAP (0/100, 10/90, 30/70, 50/50, 70/30 and 100/0) powders. Furthermore the effect of phase composition on biological and mechanical properties of the scaffold was investigated. The results showed that both the fracture toughness and compressive strength increased with increasing content of TCP from 0 to 30 wt.%, and then dropped with a further increasing content of TCP. The scaffold made of TCP/HAP with a ratio of 30/70 exhibited the optimum fracture toughness (1.33 MPa m 1/2 ) and compressive strength (18.35 MPa). After the scaffolds were soaked in SBF for 7 days, the apatite agglomerates formed on the surface of the scaffolds and the dissolution rate of the scaffolds increased with the increasing content of the TCP. In vitro cell culture indicated that a balance between biological stability and biodegradation rate was helpful for cell adherence and proliferation. It was concluded that the scaffold sintered with TCP/HAP(30/70) performed with optimum mechanical and biological properties. ► Porous ceramic scaffolds with different ratios of TCP/HAP were fabricated by SLS. ► BCP scaffolds exhibit better mechanical properties than HAP or TCP scaffolds. ► The bioactivity of scaffolds can be controlled by adjusting the TCP/HAP ratio. ► TCP/HAP(30/70) exhibit optimal comprehensive properties.

Fabrication of in-situ foamed chitosan/β-TCP scaffolds for bone tissue engineering application

The present work describes the manufacturing process of biodegradable porous material for bone tissue engineering application. The matrixes were produced by chemical foaming of chitosan solutions (CH). The method was based on CO2 release directly in the polymer by means of reaction between acetic acid and sodium bicarbonate acting as a foaming agent. The method allowed obtaining the materials with pores ranging from 10 to 1000μm and inner porosity close to 90%. The degradability of the materials was influenced by TCP content and decreased with extending inorganic phase contribution. Along with calcium phosphate content the Young modulus values were enclosed in the range of 0.02–0.5MPa. Preliminary cytocompatibilty studies revealed cell affinity of the materials manufactured.

Fabrication, mechanical and in vivo performance of polycaprolactone/tricalcium phosphate composite scaffolds

This paper explores the use of selective laser sintering (SLS) for the generation of bone tissue engineering scaffolds from polycaprolactone (PCL) and PCL/tricalcium phosphate (TCP). Different scaffold designs are generated, and assessed from the point of view of manufacturability, porosity and mechanical performance. Large scaffold specimens are produced, with a preferred design, and are assessed through an in vivo study of the critical size bone defect in sheep tibia with subsequent microscopic, histological and mechanical evaluation. Further explorations are performed to generate scaffolds with increasing TCP content. Scaffold fabrication from PCL and PCL/TCP mixtures with up to 50mass% TCP is shown to be possible. With increasing macroporosity the stiffness of the scaffolds is seen to drop; however, the stiffness can be increased by minor geometrical changes, such as the addition of a cage around the scaffold. In the animal study the selected scaffold for implantation did not perform as well as the TCP control in terms of new bone formation and the resulting mechanical performance of the defect area. A possible cause for this is presented.

Strain rate dependency of mechanical properties of TCP/PLLA composites after immersion in simulated body environments

In order to clarify strain rate dependency of mechanical properties of β-tricalcium phosphate (TCP)/poly(l-lactic acid) (PLLA) composites after immersion in simulated body environment, tensile tests at various loading rate were conducted on the TCP/PLLA specimens with and without immersion. TCP contents in the composite were 5, 10 and 15 wt%. Phosphate buffered solution was selected as simulated body environment and immersion periods were 8, 16 and 24weeks. Young’s modulus and tensile strength increased with increasing strain rates. However, the strain rate dependencies decreased with immersion. Swelling and cracks around TCP agglomerations were observed in the cross-section of 15 wt% specimen after 24weeks immersion. From the fracture surface observation, voids existed only in the ductile fracture surface of the specimen without immersion, whereas they existed in both ductile and brittle surface of the specimen with immersion. These results indicated that diffused water through the interfaces between TCP and PLLA hydrolyzed and weakened the interfaces and/or matrix near the interfaces.

Effects of strain rate on the mechanical properties of tricalcium phosphate/poly(l-lactide) composites

Bioactive ceramic/bioresorbable plastic composites have been expected as materials for the bone fracture fixations which have more biocompatibility than monolithic bioresorbable plastics. Many studies have been conducted on these materials. Most studies, however, focused on the mechanical properties under static loading. In the actual usage, these materials are loaded dynamically. In this study, effects of strain rate on the mechanical properties of tricalcium phosphate/poly(L: -lactide) (TCP/PLLA) composites were investigated experimentally and analytically. The TCP/PLLA composites containing three different TCP contents (5, 10 and 15 wt.%) were prepared by injection molding. In order to characterize the mechanical properties, tensile and compressive tests were conducted. The results of tensile tests indicated that the Young's moduli of composites increased with increasing TCP contents. For each TCP contents, tensile Young's modulus kept constant up to strain rate of 10(-1)/s. On the other hand, tensile strength increased with increasing strain rate. The effect of strain rate became larger with decreasing TCP contents, which means the strain rate dependency of the PLLA is more effective than that of TCP. From the results of compressive tests, similar results with tensile tests were obtained. That is, compressive Young's modulus kept constant up to strain rate of 10(-1)/s and the 0.2% proof stress increased with increasing strain rate. In order to predict the mechanical behavior of TCP/PLLA composites, the micro-damage mechanics was proposed. In this analysis, 3-phases particle reinforced composites, which include the intact particles, damaged particles and matrix, are assumed. The elastic constants are calculated with micromechanics based on the analyses by Eshelby and Mori and Tanaka. Only the debonding between particle and matrix are assumed as the damage. The nonlinearity in the stress-strain behavior of matrix PLLA is also considered. The debonding particles are assumed as voids. Void formation is calculated based on the energy criterion. The energy release rate associated with void formation was estimated by fitting the analytical results with the experimental results of the composites with 15 wt.% TCP contents for each strain rate. Then the analytical results for the composites with 5 and 10 wt.% TCP contents were compared with the experimental results. The analytical tensile stress-strain curves are in good agreement with experimental results. It is also clarified that the energy release rate associated with void formation increased with increasing strain rate.

Biodegradation kinetics of 2,4,6-trichlorophenol by Rhodococcus rhodochrous in batch culture

Kinetics of biodegradation of 2,4,6-trichlorophenol (TCP) by pure culture of Rhodococcus rhodochrous (DSM 43241) was investigated in batch culture. Batch experiments were performed with different initial TCP concentrations between 50 and 400 mg L −1 at pH 7 and 30 °C in the presence of basal salts medium containing glucose. Percent TCP and toxicity removals decreased with increasing initial TCP concentration due to toxic effects of TCP. The rate and the extent of TCP degradation increased with TCP concentration up to150 mg L −1 indicating no TCP inhibition at low TCP concentrations. TCP concentrations above 150 mg L −1 resulted in decreases both in the rate and extent of TCP degradation due to toxic effects of high TCP contents. The kinetics of TCP biodegradation was modeled by relating the initial TCP degradation rates with the initial TCP concentrations using the non-competitive inhibition model. The kinetic constants were determined by using the experimental data. Percent toxicity removal was also quantified along with TCP removal which decreased with increasing initial TCP concentrations due to toxic effects of TCP.

Evaluation of a novel biphasic calcium phosphate in standardized bone defects. A histologic and histomorphometric study in the mandibles of minipigs

A novel biphasic calcium phosphate (CaP) granulate consisting of hydroxyapatite (HA) and beta-tricalciumphosphate (TCP) was compared with pure HA and pure TCP and with autograft as positive control. Four standardized bone defects were prepared in both mandibular angles of 16 minipigs and grafted with autogenous bone chips, HA, HA/TCP (60% : 40%), or TCP. Histologic and histomorphometric analysis of bone formation and graft degradation followed healing periods of 2, 4, 8, and 24 weeks. 2 weeks: more bone formation in defects filled with autograft than with the three CaP materials (P<0.05). 4 weeks: bone formation differed significantly (P<0.05) between all four materials (autograft>TCP>HA/TCP>HA). 8 weeks: more bone formation in defects with autograft and TCP than with HA/TCP (P<0.05), and HA/TCP had more bone formation than HA (P<0.05). 24 weeks: no difference in bone formation between the groups. Autograft and TCP resorbed quickly and almost completely over 8 weeks, whereas HA/TCP and HA showed limited degradation over 24 weeks. All defects healed with mature lamellar bone and intimate contact between bone and the remaining graft material. The rate of bone formation corresponded to the content of TCP in the CaP materials.