Injectable Calcium Phosphate Bone Cement Research Articles

Mesoporous Bioactive Glass-Incorporated Injectable Strontium-Containing Calcium Phosphate Cement Enhanced Osteoconductivity in a Critical-Sized Metaphyseal Defect in Osteoporotic Rats.

In this study, the in vitro and in vivo bone formation behavior of mesoporous bioactive glass (MBG) particles incorporated in a pasty strontium-containing calcium phosphate bone cement (pS100G10) was studied in a metaphyseal fracture-defect model in ovariectomized rats and compared to a plain pasty strontium-containing calcium phosphate bone cement (pS100) and control (empty defect) group, respectively. In vitro testing showed good cytocompatibility on human preosteoblasts and ongoing dissolution of the MBG component. Neither the released strontium nor the BMG particles from the pS100G10 had a negative influence on cell viability. Forty-five female Sprague-Dawley rats were randomly assigned to three different treatment groups: (1) pS100 (n = 15), (2) pS100G10 (n = 15), and (3) empty defect (n = 15). Twelve weeks after bilateral ovariectomy and multi-deficient diet, a 4 mm wedge-shaped fracture-defect was created at the metaphyseal area of the left femur in all animals. The originated fracture-defect was substituted with pS100 or pS100G10 or left empty. After six weeks, histomorphometrical analysis revealed a statistically significant higher bone volume/tissue volume ratio in the pS100G10 group compared to the pS100 (p = 0.03) and empty defect groups (p = 0.0001), indicating enhanced osteoconductivity with the incorporation of MBG. Immunohistochemistry revealed a significant decrease in the RANKL/OPG ratio for pS100 (p = 0.004) and pS100G10 (p = 0.003) compared to the empty defect group. pS100G10 showed a statistically higher expression of BMP-2. In addition, a statistically significant higher gene expression of alkaline phosphatase, osteoprotegerin, collagen1a1, collagen10a1 with a simultaneous decrease in RANKL, and carbonic anhydrase was seen in the pS100 and pS100G10 groups compared to the empty defect group. Mass spectrometric imaging by time-of-flight secondary ion mass spectrometry (ToF-SIMS) showed the release of Sr2+ ions from both pS100 and pS100G10, with a gradient into the interface region. ToF-SIMS imaging also revealed that resorption of the MBG particles allowed for new bone formation in cement pores. In summary, the current work shows better bone formation of the injectable pasty strontium-containing calcium phosphate bone cement with incorporated mesoporous bioactive glass compared to the bioactive-free bone cement and empty defects and can be considered for clinical application for osteopenic fracture defects in the future.

Complications Following Intraosseous Injections of Calcium Phosphate Bone Cement in Subchondroplasty.

An alternative approach to the major problem of osteoarthritis that has begun to pique the interest of researchers focuses on the pathology of the subchondral bone, its constant cross-talk with the articular cartilage, and its interaction with the joint. The presence of bone marrow lesions, detectable on MRI scans, has proven to be a cause of pain as well as a predictor of the progression of degenerative changes. Subchondroplasty is a relatively new surgical procedure for the treatment of these lesions, in which injectable calcium phosphate bone cement is infused into the affected area percutaneously, under fluoroscopic guidance. In its use as a synthetic scaffold, calcium phosphate bone cement exhibits considerable osteoconductivity, bioabsorbability, and low toxicity, thus showing great potential for restoring subchondral biomechanical properties through structural remodeling. Although published results appear quite promising, there are certain complications that the surgeon should be aware of. We reviewed the published data regarding complications of the procedure, highlighting possible causes according to these data, and suggesting safety measures. Avascular necrosis of the talus is the most reported concern. Postsurgical pain, infection, and continuous wound drainage due to bone substitute material extravasation to the joint or soft tissue are also mentioned, necessitating further standardization of the procedure. There are no reports of permanent postoperative disability or fatal outcomes.

Injectable nanofiber-reinforced bone cement with controlled biodegradability for minimally-invasive bone regeneration.

Injectable materials show their special merits in regeneration of damaged/degenerated bones in minimally-invasive approach. Injectable calcium phosphate bone cement (CPC) has attracted broad attention for its bioactivity, as compared to non-degradable polymethyl methacrylate cement. However, its brittleness, poor anti-washout property and uncontrollable biodegradability are the main challenges to limit its further clinical application mainly because of its stone-like dense structure and fragile inorganic-salt weakness. Herein, we developed a kind of injectable CPC bone cement with porous structure and improved robustness by incorporating poly(lactide-co-glycolic acid) (PLGA) nanofiber into CPC, with carboxymethyl cellulose (CMC) to offer good injectability as well as anti-wash-out capacity. Furthermore, the introduction of PLGA and CMC also enabled a formation of initial porous structure in the cements, where PLGA nanofiber endowed the cement with a dynamically controllable biodegradability which provided room for cell movement and bone ingrowth. Interestingly, the reinforced biodegradable cement afforded a sustainable provision of Ca2+ bioactive components, together with its porous structure, to improve synergistically new bone formation and osteo-integration in vivo by using a rat model of femur condyle defect. Further study on regenerative mechanisms indicated that the good minimally-invasive bone regeneration may come from the synergistic enhanced osteogenic effect of calcium ion enrichment and the improved revascularization capacity contributed from the porosity as well as the lactic acid released from PLGA nanofiber. These results indicate the injectable bone cement with high strength, anti-washout property and controllable biodegradability is a promising candidate for bone regeneration in a minimally-invasive approach.

Self-assembling of fibers inside an injectable calcium phosphate bone cement: a feasibility study

Calcium phosphate cements are biocompatible, bioactive, and osteogenic systems which have the potential to mimic the mineral phase of native bone and the ability to be molded into bone defects and implant sites, then harden in situ to provide stability. However, their mechanical strength needs to be improved. In the last few decades, the incorporation of preformed fibers into a brittle cement matrix has been proven to increase the mechanical properties. To obtain a better cohesion between the fibers and the cement paste thus improving the mechanical performances, in this work, we attempted the formation of self-assembling fibers in a single step during the setting of our calcium phosphate cement formulations.The formation of fibers was achieved by introducing a low-molecular-weight gelator (MW < 1000 Da) derived from l-Dopa: Boc-l-Dopa (Bn)2-OH. This molecule can form supramolecular structures, owing to weak interactions, and chelate Ca2+ ions to arrange into a fibrous network. The morphological analysis revealed that the gel was able to form fibers even inside such a dense matrix and their presence provided mechanical reinforcement both when tested in compression and in bending. Micro-CT analyses showed no variation in the total porosity, but an increase of pores diameter was observed when fibers are present. Moreover, the reinforced cements were able to ensure good cell viability and to express the main gene markers that are necessary for bone formation.

Injectable bone cements: What benefits the combination of calcium phosphates and bioactive glasses could bring?

Out of the wide range of calcium phosphate (CaP) biomaterials, calcium phosphate bone cements (CPCs) have attracted increased attention since their discovery in the 1980s due to their valuable properties such as bioactivity, osteoconductivity, injectability, hardening ability through a low-temperature setting reaction and moldability. Thereafter numerous researches have been performed to enhance the properties of CPCs. Nonetheless, low mechanical performance of CPCs limits their clinical application in load bearing regions of bone. Also, the in vivo resorption and replacement of CPC with new bone tissue is still controversial, thus further improvements of high clinical importance are required. Bioactive glasses (BGs) are biocompatible and able to bond to bone, stimulating new bone growth while dissolving over time. In the last decades extensive research has been performed analyzing the role of BGs in combination with different CaPs. Thus, the focal point of this review paper is to summarize the available research data on how injectable CPC properties could be improved or affected by the addition of BG as a secondary powder phase. It was found that despite the variances of setting time and compressive strength results, desirable injectable properties of bone cements can be achieved by the inclusion of BGs into CPCs. The published data also revealed that the degradation rate of CPCs is significantly improved by BG addition. Moreover, the presence of BG in CPCs improves the in vitro osteogenic differentiation and cell response as well as the tissue-material interaction in vivo.

Development of injectable chitosan/biphasic calcium phosphate bone cement and in vitro and in vivo evaluation

Injectable biphasic calcium phosphate bone cements (BCPCs) composed of β-tricalcium phosphate (β-TCP) and hydroxyapatite (HA) have been intensively investigated because of their high rate of biodegradation, bioactivity and osteoconductivity, which can be adjusted by changing the ratio between β-TCP and HA phases after setting. The aim of this study was to evaluate the performance of 1 wt% chitosan fiber additive with biphasic calcium phosphate as an injectable bone cement both in vitro and in vivo. In vitro evaluation of compressive strength, degradation rate, morphology, and cell and alkaline phosphatase activities was done by comparison with bone cement without β-TCP. The in vivo results for micro-CT scanning and histological examinations for three groups (control, BCPC and commercial biphasic calcium phosphate granules) were characterized and compared. After the addition of 20 wt% β-TCP to calcium phosphate cement, the initial and final setting times of the sample were 3.92 min and 11.46 min, respectively, which were not significantly different from cement without β-TCP. The degradation time of the BCPC material was longer than that of calcium phosphate cement alone. The healing process was significantly faster for BCPC than for the control and commercial product groups. Therefore, this is the first evidence that BCPC is an attractive option for bone surgery due to its faster stimulation of healing and faster degradation rate.

Injectable calcium phosphate containing zirconia short fiber with enhanced radiopacity

ABSTRACT In this work, novel injectable and radiopaque calcium phosphate bone cements were prepared using zirconia short fiber as a radiopacifier. The radiopacity, setting time, injectability, anti-washout ability, microstructure, mechanical property, and the in vitro cytocompatibility of the novel cements were evaluated thoroughly. The results reveal that the incorporation of zirconia fiber significantly improves the radiopacity of bone cement while it has no significant effect on the setting time, anti-washout ability, and injectability. The cements are still injectable and show good manual operability. Moreover, the flexural strength and compressive strength of the composite bone cement with 2 wt% fibers are enhanced. Additionally, MTT results reveal that the zirconia fiber doped cements exhibit no cytotoxicity toward osteoblastic MG63 cells, and MG63 cells can adhere and proliferate well on the cements. Therefore, calcium phosphate bone cement containing zirconia fibers has the potential to be used as a bone repair material for minimally invasive surgery.

Enhanced Osteogenesis of Injectable Calcium Phosphate Bone Cement Mediated by Loading Chondroitin Sulfate.

Toward repairing critical-sized bone defects, calcium phosphate cement (CPC) has been well recognized as a fairly promising bone graft because of its properties of injectability, self-setting, biocompatibility, and osteoconductivity. However, poor osteogenic capacity of CPC still limits its applications for meeting the demands of bone healing. In this work, chondroitin sulfate (CS), as an important component of the extracellular matrix network, was introduced into CPC to enhance its osteogenesis ability. Incorporation of CS had no evident effect on the phase, morphology, apparent porosity, and compressive strength of hydrated cement products, but it notably enhanced the injectability and improved the antiwashout property of the cement pastes. CS was able to be sustainably released from CS-CPCs in a CS-dose-dependent manner and supposed to have a long-term release potential for constant biological stimulation. CS-CPCs markedly accelerated the preferential adsorption of fibronectin. Furthermore, CS-CPCs significantly improved the adhesion, proliferation, and osteogenic differentiation of bone mesenchymal stem cells, which was synergistically mediated by the adhesion events of cells on the hydrated cements and the stimulation effects of CS molecules. Herein, utilization of CS is supposed to endow injectable calcium phosphate bone cements with enhanced osteogenic capacity and suitable physicochemical properties for numerous promising orthopedic applications.

Smart Injectable Self-Setting Monetite Based Bioceramics for Orthopedic Applications.

The present study is the first of its kind dealing with the development of a specific bioceramic which qualifies as a potential material in hard-tissue replacements. Specifically, we report the synthesis and evaluation of smart injectable calcium phosphate bone cement (CPC) which we believe will be suitable for various kinds of orthopedic and spinal-fusion applications. The smart nature of this next generation orthopedic implant is attained by incorporating piezoelectric barium titanate (BT) particles into monetite-based (dicalcium phosphate anhydrous, DCPA) CPC composition. The main goal is to take advantage of the piezoelectric properties of BT, as electromechanical effect plays a vital role in fracture healing at the defect site and bone integration with the implant. Furthermore, radiopacity of BT would help in easy detection of the CPC presence at the fracture site during surgery. Results reveal that BT addition favors important properties of bone cement such as good compressive strength, injectability, bioactivity, biocompatibility, and even washout resistance. Most importantly, the self-setting nature of the bone cements are not compromised with BT incorporation. The in vitro results confirm that the developed bone-cement abides by the standard orthopedic requirements making it apt for real-time prosthetic materials.

Preliminary in Vivo Evaluation of Bone Healing in Critical Size Bone Defects Implanted with an Injectable Calcium Phosphate Bone Cement (Osteopaste)

Introduction: A novel injectable calcium phosphate bone cement (osteopaste) has been developed. Its potential application in orthopaedics as a filler of bone defects has been studied. The biomaterial was composed of tetra-calcium phosphate (TTCP) and tricalcium phosphate (TCP) powder. The aim of the present study was to evaluate the healing process of osteopaste in rabbit tibia. Materials and method: The implantation procedure was carried out on thirty-nine of New Zealand white rabbits. The in vivo bone formation was investigated by either implanting the Osteopaste, Jectos or MIIG – X3 into a critical size defect (CSD) model in the proximal tibial metaphysis. CSD without treatment served as negative control. After 1 day, 6 and 12 weeks, the rabbits were euthanized, the bone were harvested and subjected for analysis. Results: Radiological images and histological sections revealed integration of implants with bone tissue with no signs of graft rejection. There was direct contact between osteopaste material and host bone. The new bone was seen bridging the defect. Conclusion: The result showed that Osteopaste could be a new promising biomaterial for bone repair and has a potential in bone tissue engineering.

Synthesization and characterization of poly(lactic-co-glycolic acid) / calcium phosphate bone cement from crab shells

An injectable calcium phosphate (CaP) bone cement has been widely used for musculoskeletal and bone disorder due to its biocompatible and osteoconductive properties. In this study, CaP was successfully synthesized from crab shells by a wet chemical route. Poly(lactic-co-glycolic acid) (PLGA) microspheres which have been produced through a double emulsion technique were incorporated into the CaP mixture for the purpose of bone cement solidification. The ratio of both compounds, CaP and PLGA, were set at 8:2. The CaP and PLGA/CaP bone cement were analyzed by ATR-FTIR, FESEM-EDX and contact angle analyses. The bone cement was composed of CaP and PLGA where the micro-powders of CaP were agglomerated on the PLGA microspheres. Addition of the PLGA has increased the hydrophilicity of the bone cement which will be beneficial for materials degradation and bone integration.

Natural diatomite particles: Size-, dose- and shape- dependent cytotoxicity and reinforcing effect on injectable bone cement

Natural diatomite (DT) is the ancient deposit of diatom skeleton with many regular pores of 50–200nm and also an abundant source of biogenic silica. Although silica is considered biologically safe and there is an increasing interest of using natural diatomite for biomedical applications, the toxicity information about natural diatomite is still missing. Here, cytotoxicity of natural diatomite on osteoblasts and fibroblasts were compared to hydroxyapatite and the relationships between cytotoxicity and diatomite sizes, dose, geometry or impurity were systematically investigated. Cell adhesion and interaction with diatomite particles were also fluorescently observed. The results clearly suggested a size-, dose- and shape-dependent cytotoxicity of natural diatomite. Disk-shaped diatomite particles with average size of 30μm in diameter revealed the least toxicity, while the diatomite particles with irregular shapes and sizes less than 10μm were remarkably toxic. Diatomite particles with proper sizes were then selected to investigate the reinforcing effect on injectable calcium phosphate bone cement. Results showed that diatomite significantly improved the compressive strength of bone cement but did not alter the injectability of the cement. This work provided important biocompatibility information of natural diatomite and demonstrated the feasibility of using selected diatomite as bone implant material.

An ultrasonic through-transmission technique for monitoring the setting of injectable calcium phosphate cement

An ultrasound through-transmission method to monitor the setting process of injectable calcium phosphate bone cements in body fluids is presented. This method can be used to determine the acoustic properties of the bone cement as it sets, which are linked to its material properties and provide some information about changes occurring within the cement. The development of the methodology of ultrasonic testing and execution of velocity measurements of the longitudinal and transverse waves using the through-transmission method made it possible to determine the material constants of samples during the setting and hardening process of an injectable cement paste in physiological fluids (i.e. the Young's modulus (E), the Poisson ratio (ν) and the shear modulus (G)), and to determine the degree of anisotropy of wave velocity in the samples. A strong advantage of the proposed method is that it is non-destructive, and the same sample can be used to monitor the whole process of the cement setting. The testing was performed on premixed and injectable calcium phosphate (CPC)/chitosan blend, where glycerol was used as a liquid phase. Comparisons between ultrasonic velocity and empirical tests such as compressive strength, porosity measurement, FTIR, SEM and XRD analysis at different days of immersion in Ringer's solutions showed that the ultrasonic velocity can be very useful to provide in situ information about changes occurring within the cement.

Reinforcement of injectable calcium phosphate cement by gelatinized starches.

Current injectable calcium phosphate bone cements (CPC) encounter the problems of low strength, high brittleness, and low cohesion in aqueous environment, which greatly hinder their clinical applications for loading-bearing bone substitution and minimally invasive orthopedic surgeries. Here, a strategy of using gelatinized starches to reinforce injectable CPC was investigated. Four types of starches, namely corn starch, crosslinked starch, cationic starch, and Ca-modified starch, were studied for their influence on CPC mechanical properties, injectability, setting times, anticollapsibility, and cytocompatibility. Gelatinized starch significantly improved compressive strength and modulus as well as strain energy density of CPC to different extents. Specifically, both corn starch and Ca-modified starch revealed sixfold and more than twofold increases in the compressive strength and modulus of CPC, respectively. The addition of gelatinized starches with proper contents increased the injectability and anticollapsibility of CPC. In addition, osteoblast proliferation tests on leaching solution of modified cements showed that gelatinized starches had no adverse effect on cell proliferation, and all cement samples resulted in better osteoblast proliferation compared to phosphate-buffered solution control. The mechanisms behind the reinforcing effect of different starches were preliminarily studied. Two possible mechanisms, reinforcement by the second phase of gelatinized starch and strong interlocking of apatite crystals, were proposed based on the results of starch zeta potential and viscosity, cement microstructure, and resultant mechanical properties. In conclusion, incorporating gelatinized starches could be an effective, facile, and bio-friendly strategy to reinforce injectable CPC and improve its mechanical stability, and thus, should be further studied and developed.

Ready-to-use injectable calcium phosphate bone cement paste as drug carrier

Current developments in calcium phosphate cement (CPC) technology concern the use of ready-to-use injectable cement pastes by dispersing the cement powder in a water-miscible solvent, such that, after injection into the physiological environment, setting of cements occurs by diffusion of water into the cement paste. It has also been demonstrated recently that the combination of a water-immiscible carrier liquid combined with suitable surfactants facilitates a discontinuous liquid exchange in CPC, enabling the cement setting reaction to take place. This paper reports on the use of these novel cement paste formulations as a controlled release system of antibiotics (gentamicin, vancomycin). Cement pastes were applied either as a one-component material, in which the solid drugs were physically dispersed, or as a two-component system, where the drugs were dissolved in an aqueous phase that was homogeneously mixed with the cement paste using a static mixing device during injection. Drug release profiles of both antibiotics from pre-mixed one- and two-component cements were characterized by an initial burst release of ∼7–28%, followed by a typical square root of time release kinetic for vancomycin. Gentamicin release rates also decreased during the first days of the release study, but after ∼1week, the release rates were more or less constant over a period of several weeks. This anomalous release kinetic was attributed to participation of the sulfate counter ion in the cement setting reaction altering the drug solubility. The drug-loaded cement pastes showed high antimicrobial potency against Staphylococcus aureus in an agar diffusion test regime, while other cement properties such as mechanical performance or phase composition after setting were only marginally affected.

Effects of EMD in combination with bone swaging and calcium phosphate bone cement on periodontal regeneration in one‐wall intrabony defects in dogs

Although the application of EMD is a widely accepted periodontal-regenerative therapy, its effects on noncontained intrabony defects are unpredictable because of the lack of a space-making property. The combined use of EMD and autogenous bone grafts reportedly stimulates significant periodontal regeneration in intrabony defects. The aim of the present study was to evaluate the effects of EMD in combination with bone swaging (BS) and injectable calcium phosphate bone cement (CPC), which was placed into the spaces between the grafted swaged bone and the proximal host bone, on periodontal healing in one-wall intrabony defects in dogs. One-wall intrabony defects (3 mm wide and 5 mm deep) were surgically created on the mesial and distal sides of the bilateral mandibular premolars in four dogs. The 16 defects were assigned to one of the following treatments: EMD only, BS only, EMD with BS (EMD + BS), or EMD with BS and CPC (EMD + BS + CPC). The animals were killed 8 wk after surgery for histologic evaluation. The height of newly formed bone was significantly greater in the EMD + BS + CPC group (3.73 ± 0.30 mm) than in the BS-only (2.74 ± 0.33 mm; p < 0.05) and EMD + BS (2.88 ± 0.98 mm; p < 0.05) groups. The area of newly formed bone was significantly larger in the EMD + BS + CPC group (5.68 ± 1.66 mm(2)) than in the EMD-only (3.68 ± 0.33 mm(2); p < 0.05), BS-only (3.48 ± 1.26 mm(2); p < 0.05) and EMD + BS (3.38 ± 1.37 mm(2); p < 0.05) groups. The EMD-only (4.63 ± 0.42 mm), EMD + BS (4.67 ± 0.30 mm) and EMD + BS + CPC (4.78 ± 0.54 mm) groups showed significantly greater cementum formation than did the BS-only group (3.93 ± 0.56 mm; p < 0.05). These results indicate that treatment with EMD + BS + CPC promotes favorable periodontal healing in one-wall intrabony defects in dogs.

Effect of bone swaging with calcium phosphate bone cement on periodontal regeneration in dogs

The present study evaluated the effects of bone swaging (BS) with injectable calcium phosphate bone cement (CPC) on periodontal healing in 1-wall intrabony defects in dogs. Surgically created 1-wall intrabony defects were treated with BS, CPC, BS with CPC (BS/CPC), or open-flap debridement (OFD). The animals were humanely killed for histologic evaluation at 8 weeks. New bone formation occurred from the host bone toward the coronal region of the defects in the BS/CPC group. The height of new bone formation was significantly higher in the BS/CPC group than in the other groups (P < .05). New cementum formation was most notable in the BS/CPC group, where it was significantly greater than in the OFD and CPC groups (P < .05). Within the limitations of the present study, it was concluded that BS/CPC treatment effectively promoted new bone and cementum formation in 1-wall intrabony defects in dogs.

Granuloma debridement and the use of an injectable calcium phosphate bone cement in the treatment of osteolysis in an uncemented total knee replacement

Polyethylene particulate debris-induced periprosthetic osteolysis is a known complication of knee arthroplasty surgery, and may result in the need for revision surgery. The management of these bony defects can be surgically challenging, and full revisions of well-fixed total knee components can lead to substantial bone loss. We present the case of a 71 year old man who developed knee pain and osteolysis around an uncemented total knee replacement. Due to significant medical comorbidies he was treated by percutaneous cyst granuloma debridement and grafting using an injectable calcium phosphate bone substitute. There were no wound complications, and the patient was allowed to fully weight-bear post-operatively. Histopathology and microbiology of the cyst material confirmed polyethylene granulomata without any evidence of infection. At 6 weeks post-operatively the patient's previous knee pain had resolved, he was able to comfortably fully weight-bear. Preoperative scores (Knee Society Score (KSS) 41, WOMAC score 46.2, and Oxford Knee Score 39) had all improved at the 12-month post-operative review KSS 76, WOMAC 81.7 and Oxford Knee score 21). This is a safe and effective technique with minimal morbidity and may be an appropriate treatment modality when more extensive revision surgery is not possible. The case is discussed with reference to the literature.

Introduction of enzymatically degradable poly(trimethylene carbonate) microspheres into an injectable calcium phosphate cement

Poly(trimethylene carbonate) (PTMC) is an enzymatically degradable polyester with rubber-like properties. Introduction of this polymer into an injectable calcium phosphate bone cement can therefore be used to introduce macroporosity into the cement for tissue engineering purposes as well as to improve mechanical properties. Aim of this study was to investigate calcium phosphate cements with incorporated PTMC microspheres (PTMC CPCs) on their physical/mechanical properties and in vitro degradation characteristics. Therefore, composites were tested on setting time and mechanical strength as well as subjected to phosphate buffered saline (PBS) and enzyme containing medium. PTMC CPCs (12.5 and 25 wt%) with molecular weights of 52.7 kg mol −1 and 176.2 kg mol −1 were prepared, which showed initial setting times similar to that of original CPC. Though compression strength decreased upon incorporation of PTMC microspheres, elastic properties were improved as strain-at-yield increased with increasing content of microspheres. Sustained degradation of the microspheres inside PTMC CPC occurred when incubated in the enzymatic environment, but not in PBS, which resulted in an interconnected macroporosity for the 25 wt% composites.

Comparison of Injectable Calcium Phosphate Bone Cement Grafting and Open Flap Debridement in Periodontal Intrabony Defects: A Randomized Clinical Trial

Regeneration of lost periodontium is the ultimate goal of periodontal therapy. Bone grafts, guided tissue regeneration, and application of growth factors are used for periodontal regeneration. This study aimed to evaluate the clinical efficacy of a new, injectable calcium phosphate bone cement (CPC) in human periodontal intrabony defects. Thirty subjects (mean age, 53.4 +/- 9.1 years) with periodontitis and narrow intrabony defects were enrolled in the study. Subjects were classified randomly into the CPC graft group (N = 15) or the open flap debridement (OFD) alone group (N = 15). Clinical measurements were performed at baseline and at 3, 6, 9, and 12 months; radiographs were taken at baseline, 2 weeks, and 6 and 12 months after surgery. The Student t test was used for statistical analysis. In the CPC group, six cases showed exposure or loss of the CPC within 12 months, whereas the remaining nine cases (CPC-R group) showed no adverse reaction, including infection or suppuration. Overall, CPC-R and OFD treatment groups exhibited a significant reduction in probing depth and a significant gain in clinical attachment level at 3, 6, 9, and 12 months compared to baseline values. However, there were no significant differences in any of the clinical parameters between the groups. In the CPC-R group, radiographic bone level gain appeared to be greater than in the OFD group. The present study failed to demonstrate any superior clinical outcomes for the CPC group compared to the OFD group; however, radiographs revealed more favorable results in the CPC-R group. The filling volume and stiffness of CPC may compromise the clinical outcomes for periodontal intrabony defects.