Comparative Analysis of the Tibial Component Migration After Cemented and Uncemented Total Knee Arthroplasty with a Hydroxyapatite Coating in Two, Five, and Ten Years: A Meta-Analysis / Análise comparativa da migração do componente tibial da artroplastia total do joelho cimentada versus não cimentada versus não cimentada com revestimento de hidroxapatita por dois, cinco e dez anos: uma metanálise

Abstract Objective This study evaluated and compared the tibial component migration in cemented and uncemented total knee arthroplasty (TKA) with no hydroxyapatite coating 2, 5, and 10 years after surgery. Methods This meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) based on PubMed and MeSH database queries from June to July 2022. Results The meta-analysis included eight randomized clinical studies evaluating 668 knees undergoing TKA. The maximum total point motion (MTPM) in cemented TKAs was higher in 5 years, with a mean value of 0.67 mm (95% confidence interval [CI], 0.52 to 0.87). Uncemented TKAs also presented higher mean MTPM in 5 years (1 mm; 95% CI, 0.82 to 1.22). Uncemented coated ATKs had a higher mean MTPM in 10 years (1.30 mm; 95% CI, 0.70 to 2.39). MTPM was statistically similar in the short- and long-term for cemented and uncemented techniques, with a standardized mean difference of -0.65 (95% CI, -1.65 to 0.35). Conclusion Tibial component migration in TKA was statistically similar at 2, 5, and 10 years in cemented and uncemented techniques, either with or without coating. However, due to the scarce literature, further studies are required with a longer follow-up time.

Resumo Objetivo Avaliar e comparar a migração obtida pelo componente tibial na Artroplastia Total de Joelho (ATJ) cimentada, não cimentada sem revestimento e não cimentada com revestimento de hidroxapatita aos 2, 5 e 10 anos pós operatório. Métodos Esta metanálise foi conduzida de acordo com o Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Foi realizada busca a partir das bases de dados PubMed e MeSH no período de junho a julho de 2022. Resultados Oito ensaios clínicos randomizados foram incluídos. Um total de 668 joelhos submetidos a ATJ foram avaliados. Observou-se que a média de Maximun Total Point Motion (MTPM) nas ATJ cimentada foi maior em experimentos com cinco anos com média de 0,67 mm (IC95% - 0,52 a 0,87), as ATJ não cimentadas com revestimento de hidroxapatita também obtiveram maior média neste período (1mm; IC95% - 0,82 a 1,22). Em ATJ não cimentada sem revestimento o maior MTPM médio ocorreu no período de 10 anos (1,30mm; IC95% - 0,70 a 2,39). O MTPM foi estatisticamente semelhante no curto e longo prazo ao comparar as técnicas cimentada e não cimentada, com diferença média padronizada -0,65 (IC95%, -1,65 a 0,35). Conclusão A migração obtida pelo componente tibial na artroplastia total de joelho (ATJ) foi estatisticamente semelhante em 2, 5 e 10 anos ao comparar as técnicas cimentada e não cimentada (com e sem revestimento). Entretanto, devido ao pequeno número de artigos existentes, são necessários mais estudos clínicos sobre tais técnicas e com maior tempo de acompanhamento.

"RichBlend" protocol for full-face filling and collagen biostimulation / Protocolo "RichBlend" para preenchimento facial e bioestimulação de colágeno

ABSTRACT The "RichBlend" protocol was designed for facial filling and collagen biostimulation, by means of a mixture of calcium hydroxyapatite (CaHA), hyaluronic acid (AH) and autologous platelet concentrates. This work reports the case of a 53-year-old patient with cutaneous photoaging, loss of facial volume, multiple rhythms in the frontal and periorbital regions, also marked skin flaccidity, especially the eyelid. The treatment was done with botulinum toxin (65 U) and the "RichBlend" protocol. Venipuncture was performed and the blood was centrifuged to obtain i-PRF (injectable platelet-rich fibrin) and plasma gel. After venipuncture and blood centrifugation, i-PRF and plasma gel were obtained. CaHA (Radiesse®) was diluted: a) in saline solution + i-PRF (hyperdilution) for biostimulationof the lower third of the face; and b) in AH (Juvederm Ultraplus XC®) + plasma gel, for hydrolifting on the forehead and dark circles, malar and temples. Plasma gel was applied to the nasogenian grooves and then the entire face was properly massaged. The "RichBlend" protocol rejuvenated the patient, as it promoted filling, volumizing, collagen formation (biostimulation), reduction of flaccidity, in addition to skin whitening. Since HA and CaHA are high-cost products, their mixture with autologous platelet concentrates, in liquid or gel form, allows the use of a greater amount of filled and biostimulator material on the face, at a more affordable cost.

RESUMO O protocolo "RichBlend" foi idealizado para preenchimento facial e bioestimulação de colágeno, por meio da mistura de hidroxiapatita de cálcio (CaHA), ácido hialurônico (AH) e concentrados plaquetários autólogos. Este trabalho relata o caso de um paciente de 53 anos, com fotoenvelhecimento cutâneo, perda de volume facial, múltiplas rítides nas regiões frontal e periorbital, apresentando também acentuada flacidez cutânea, especialmente palpebral. Foi feito o tratamento com toxina botulínica (65 U) e protocolo "RichBlend". Foi realizada a venopunção e o sangue foi centrifugado para obtenção da i-PRF (fibrina rica em plaquetas injetável) e do plasma gel. Após venopunção e centrifugação sanguínea, obtiveram-se a i-PRF e o plasma gel. A CaHA (Radiesse®) foi diluída: a) em soro + i-PRF (hiperdiluição) para bioestimulação do terço inferior da face; e b) em AH (Juvederm Ultraplus XC®) + plasma gel, para hidrolifting na fronte e preenchimentos de olheira, malar e têmporas. Plasma gel foi aplicado nos sulcos nasogenianos e, em seguida, toda a face foi devidamente massageada. O protocolo "RichBlend" rejuvenesceu o paciente, pois promoveu preenchimento, volumização, formação de colágeno (bioestimulação), redução da flacidez, além do clareamento cutâneo. Uma vez que o AH e a CaHA são produtos de alto custo, sua mistura com os concentrados plaquetários autólogos, na forma líquida ou gel, permite a utilização de uma maior quantidade de material preenchedor e bioestimulador na face, com custo mais acessível.

Clinical Comparison of Eggshell Derived Calcium Hydroxyapatite with Dycal® as Indirect Pulp Capping Agents in Primary Molars

Abstract Objective: To evaluate and compare the efficacy of eggshell derived calcium hydroxyapatite with Dycal® as indirect pulp capping material in primary molars. Material and Methods: A total of 32 carious primary molars from 22 children (6-10-years) were screened, of which 26 primary molars meeting inclusion criteria were selected and equally divided into two groups. At the first appointment, the infected dentin was excavated using a spoon excavator after treating the carious part with Carie-Care™ chemomechanical caries removal agent. After this, eggshell derived calcium hydroxyapatite in Group 1 and Dycal® in Group 2 were used as liners followed by restoration of the cavity with type IX glass ionomer cement. Clinical assessment for pain and radiographic assessment for measurement of the amount of reparative dentin thickness formation was performed at baseline, 8 weeks and 3 months. The data were subjected to statistical analysis by one-way ANOVA and Kruskal-Wallis tests. Results: Higher mean reparative dentin formation was found in eggshell derived calcium hydroxyapatite group than Dycal® group at the end of 8 weeks and 3 months and the difference was significant statistically (p<0.001). Conclusion: Eggshell derived calcium hydroxyapatite seems to be a suitable alternative to Dycal® (calcium hydroxide) that can be used as a liner for indirect pulp capping in primary molars.

Influence of the geometry of nanostructured hydroxyapatite and alginate composites in the initial phase of bone repair

Abstract Purpose: To analyze, histomorphologically, the influence of the geometry of nanostructured hydroxyapatite and alginate (HAn/Alg) composites in the initial phase of the bone repair. Methods: Fifteen rats were distributed to three groups: MiHA - bone defect filled with HAn/Alg microspheres; GrHA - bone defect filled with HAn/Alg granules; and DV - empty bone defect; evaluated after 15 days postoperatively. The experimental surgical model was the critical bone defect, ≅8.5 mm, in rat calvaria. After euthanasia the specimens were embedded in paraffin and stained with hematoxylin and eosin, picrosirius and Masson-Goldner's trichrome. Results: The histomorphologic analysis showed, in the MiHA, deposition of osteoid matrix within some microspheres and circumjacent to the others, near the bone edges. In GrHA, the deposition of this matrix was scarce inside and adjacent to the granules. In these two groups, chronic granulomatous inflammation was noted, more evident in GrHA. In the DV, it was observed bone neoformation restricted to the bone edges and formation of connective tissue with reduced thickness in relation to the bone edges, throughout the defect. Conclusion: The geometry of the biomaterials was determinant in the tissue response, since the microspheres showed more favorable to the bone regeneration in relation to the granules.

Potencial of different hydroxyapatites as biomaterials in the bone remodeling

Abstract Purpose: To analyze the therapeutic potentials of different hydroxyapatites used for the correction of bone defects in rats. Methods: Forty rats, male, albino wistar, were distributed in 4 groups. They were submitted to a 3.5 mm defect in tibia. They received low purity hydroxyapatite, Strontium hydroxyapatite and hydroxyapatite doped with gallium, having a seven day evaluation time. Histopathology slides were stained with hematoxylin-eosin, for morphological evaluation. Were analyzed inflammatory processes, necrosis, presence of osteoclasts and osteoblasts, presence of the material, presence of white cells, neovascularization and bone neoformation. Results: It was observed that the groups HAPSr and HAPGa, presented better results of trabecular bone, hyaline cartilage and bone marrow more organized. Conclusion: There was improvement in the repair of the bone defect produced, showing that these hydroxyapatites are effective osteoinductive, osteoconductive, osteintegrant agents and have biocompatibility, and may be indicated for use in defect repairs.

A comparison of different bone graft materials in peri-implant guided bone regeneration

Abstract The aim of this study was to compare the effects of hydroxyapatite (HA), deproteinized bovine bone (DPB), human-derived allogenic bone (HALG), and calcium sulfate (CAP) graft biomaterials used with titanium barriers for bone augmentation to treat peri-implant defects in rat calvarium treated by guided bone regeneration (GBR). Thirty-two female Sprague-Dawley rats were divided into four groups: DPB, HALG, HA, and CAP. One titanium barrier was fixed to each rat's calvarium after the titanium implants had been fixed. In total, 32 titanium implants and barriers were used. Ninety days after the surgical procedure, all the barriers were removed. After decalcification of bone tissue, the titanium implants were removed gently, and new bone regeneration in the peri-implant area was analyzed histologically. Immunohistochemical staining of vascular endothelial growth factor (VEGF) was also performed. There were no statistically significant between-group differences in new bone regeneration or VEGF expression after 3 months. According to the results of the histological and immunohistochemical analyses, none of the grafts used in this study showed superiority with respect to new bone formation.

Behavior study of the doped castor bean polymer rod with bioactive glass and hidroxyapatite in mice femur medullary canal

Abstract Purpose To evaluate the polymer doped rods behavior with bioactive glass and hydroxyapatite for possible application as a fracture fixing method. Methods Twenty eight Rattus norvegicus Wistar underwent bone defect for access to the femoral medullary canal and distributed into three experimental groups: group A - doped castor bean polymer with bioactive glass; group B - castor bean polymer and; group C - castor bean polymer doped with bioactive glass and hydroxyapatite. After 15 and 60 evaluation days, the femurs were removed and sent for histology and scanning electron microscopy. Results Initially mild and moderate inflammatory infiltrate is observed that decreases as time goes by, and the presence of connective tissue capsule around the graft in all groups. Regarding the biomaterials resorption little was observed. The implanted rods did not favor the osteoconductive process in the femoral medullary canal which was observed only in the C15 group. Conclusions The association of castor bean polymer, bioactive glass and hydroxyapatite was biocompatible and osteointegrable. The osteoconductive only occurred in the presence of hydroxyapatite and bioactive glass (C15 Group) and little biodegradation was observed.

Physicochemical characterization of porcine bone-derived grafting material and comparison with bovine xenografts for dental applications

PURPOSE: The physicochemical properties of a xenograft are very important because they strongly influence the bone regeneration capabilities of the graft material. Even though porcine xenografts have many advantages, only a few porcine xenografts are commercially available, and most of their physicochemical characteristics have yet to be reported. Thus, in this work we aimed to investigate the physicochemical characteristics of a porcine bone grafting material and compare them with those of 2 commercially available bovine xenografts to assess the potential of xenogenic porcine bone graft materials for dental applications. METHODS: We used various characterization techniques, such as scanning electron microscopy, the Brunauer-Emmett-Teller adsorption method, atomic force microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, and others, to compare the physicochemical properties of xenografts of different origins. RESULTS: The porcine bone grafting material had relatively high porosity (78.4%) and a large average specific surface area (SSA; 69.9 m²/g), with high surface roughness (10-point average roughness, 4.47 µm) and sub-100-nm hydroxyapatite crystals on the surface. Moreover, this material presented a significant fraction of sub-100-nm pores, with negligible amounts of residual organic substances. Apart from some minor differences, the overall characteristics of the porcine bone grafting material were very similar to those of one of the bovine bone grafting material. However, many of these morphostructural properties were significantly different from the other bovine bone grafting material, which exhibited relatively smooth surface morphology with a porosity of 62.0% and an average SSA of 0.5 m²/g. CONCLUSIONS: Considering that both bovine bone grafting materials have been successfully used in oral surgery applications in the last few decades, this work shows that the porcine-derived grafting material possesses most of the key physiochemical characteristics required for its application as a highly efficient xenograft material for bone replacement.

Avaliação do potencial remineralizador de géis contendo nano-hidroxiapatita em lesões iniciais de cárie em esmalte

A formação de cárie incipiente de esmalte é um processo reversível e regulado pelo grau desaturação de minerais nos fluidos orais. O processo de reversão se dá através da remineralização. O objetivo do presente trabalho foi avaliar, in vitro, o potencial remineralizador de géis experimentais contendo nano-hidroxiapatita, associada ou não ao flúor, através de um modelo de indução de lesão de cárie inicial em esmalte. Foram utilizados incisivos bovinos cortados em blocos de esmalte e aleatorizados em cinco grupos: GC (gel semflúor e sem nano-hidroxiapatita); GF (gel de flúor experimental); GN (gel de nanohidroxiapatita);GNF (gel de nano-hidroxiapatita e flúor); GFC (gel de flúor comercial 1.23%). Os espécimes foram submetidos a um desafio cariogênico para indução química de lesão inicial de cárie. O desafio cariogênico foi realizado com a imersão das amostras em 2 mL desolução desmineralizante/mm2 de esmalte exposto, durante 36h a 37oC, sob agitação. Logoapós, os géis foram aplicados uma única vez durante quatro minutos e os espécimes foram submetidos a um modelo de ciclagem de pH durante oito dias, intercalando 4 horas em solução desmineralizante e 20 horas em solução remineralizante. A análise de microdureza Knoop foi realizada em três momentos: antes da indução de cárie em esmalte, após a indução de cárie e, finalmente, após a ciclagem de pH. A microdureza em corte longitudinal foi executada após o último dia de ciclagem de pH. Logo após, com o auxílio de microscopia eletrônica de varredura (MEV), foram avaliadas as características superficiais dos espécimes e por espectroscopia de infravermelho com transformada de Fourier (FTIR) foram avaliadas as composições químicas de cada grupo. Os dados obtidos foram submetidos à análise devariância e, em seguida, ao teste T (p<0,05)...

The formation of enamel’s incipient caries is a reversible process and is regulated by the levelof saturation of minerals in the oral fluids. The reversion process takes place throughremineralization. The aim of the study was to evaluate, in vitro, the remineralizing potential ofexperimental gels containing nano-hydroxyapatite, associated or not with fluoride, through amodel of induction of enamel’s early caries lesion. For this study, bovine incisors were cutinto enamel blocks and randomized in five groups: GC (gel without fluoride and without nanohydroxyapatite);GF (experimental fluoride gel); GN (nano-hydroxyapatite gel); GNF (nanohydroxyapatitegel and fluoride); GFC (commercial fluoride gel 1.23%). The specimens weresubjected to a cariogenic challenge in order to chemically induce an early caries lesion. Thecariogenic challenge was performed through immersing the samples in 2 mL ofdemineralizing solution/mm2 of exposed enamel for 36h at 37ºC under agitation. Right afterthis, the gels were applied only once during 4 minutes and the specimens were subjected to apH-cycling model for 8 days, alternating between 4 hours in demineralizing solution an 20hours in remineralizing solution. The Knoop microhardness test analysis was initiallyperformed; after inducing caries in enamel; and after pH-cycling. The longitudinal-cutmicrohardness was executed after the last day of pH-cycling. Right after this, using scanningelectron microscopy (SEM), the specimens’ superficial characteristics were evaluated and thechemical compositions of each group were evaluated with Fourier Transform Infrared (FTIR)spectroscopy. The data obtained were subjected to the analysis of variance and then to the Ttest (p<0,05)...

Randomized controlled clinical trial of 2 types of hydroxyapatite-coated implants on moderate periodontitis patients

PURPOSE: The aim of this study was to compare and analyze the peri-implant tissue conditions and prospective clinical outcomes associated with 2 types of hydroxyapatite (HA)-coated implants: (1) fully HA-coated implants and (2) partially HA-coated implants with resorbable blast medium on the coronal portion of the threads. METHODS: Forty-four partially edentulous patients were randomly assigned to undergo the placement of 62 HA-coated implants, and were classified as the control group (partially HA-coated, n=30) and the test group (fully HA-coated, n=32). All patients had chronic periodontitis with moderate crestal bone loss around the edentulous area. The stability and clinical outcomes of the implants were evaluated using the primary and secondary implant stability quotient (ISQ), as well as radiographic, mobility, and peri-implant soft tissue assessments around the implants. The Wilcoxon signed-rank test and the Mann-Whitney test were used to evaluate differences between and within the 2 groups, with P values 0.05). No significant differences were found in the survival rate (group I, 100%; group II, 100%) or the success rate (group I, 93.3%; group II, 93.8%). The fully HA-coated implants also did not significantly increase the risk of peri-implantitis (P>0.05). CONCLUSIONS: The fully HA-coated implants did not lead to an increased risk of peri-implantitis and showed good retention of the crestal bone, as well as good survival and success rates. Our study suggests that fully HA-coated implants could become a reliable treatment alternative for edentulous posterior sites and are capable of providing good retention of the crestal bone.

Nano-hydroxyapatite film as a support to improve the proliferation of human umbilical vein endothelial cells / 中国组织工程研究

BACKGROUND:A new type of nano-hydroxyapatite artificial mechanical heart valve has been developed using pulsed laser deposition technology at the Department of Materials, Hefei University and Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, China. OBJECTIVE:To investigate the compatibility of nano-hydroxyapatite artificial mechanical heart valve with human umbilical vein endothelial cels. METHODS:Human umbilical vein endothelial cels were in vitroisolated, cultured and passaged to the 2-4 generations, and then the cel suspension was inoculated onto the nano-hydroxyapatite artificial mechanical heart valve. After 3, 7, 12 days of culture, the cel growth on the artificial mechanical heart valve was observed under scanning electron microscope. In addition, the human umbilical vein endothelial cels were respectively cultured in room-temperature and high-temperature extract liquids of nano-hydroxyapatite artificial mechanical heart valve, high-density polyethylene and phenol solution extracts for 72 hours, and then, the proliferation of cels was detected by MTT method. RESULTS AND CONCLUSION:Under the scanning electron microscope, the human umbilical vein endothelial cels were fusiform- or polygon-shaped with protuberances adhered to the artificial mechanical heart value at 3 days of culture; the cels were stretched thoroughly and fused at 7 days of culture; and the cels were confluent to pieces that tightly overlaid the heart valve surface and the extracelular matrix was formed localy at 21 days of culture. Results from MTT test displayed that the nano-hydroxyapatite artificial mechanical heart valve had no cytotoxicity to the human umbilical vein endothelial cels, indicating a good cytocompatibility.

Application of nano-artificial bone in anterior cervical fusion / 中国组织工程研究

BACKGROUND:Nano-hydroxyapatite/polyamide artificial bone has good biocompatibility and strong tissue binding force, which exerts a significant role in the recovery of neurological function. OBJECTIVE: To investigate the clinical effect of nano-hydroxyapatite/polyamide artificial bone in anterior cervical fusion. METHODS: Ninety patients with cervical spondylosis and traumatic dislocation of the cervical spine were randomized into observation group and control group. Patients in the two groups underwent nano-hydroxyapatite/polyamide artificial bone and autologous iliac bone implantation, respectively. Surgical condition, Japanese Orthopaedic Association score, vertebral height loss and bone fusion rate were compared and analyzed at different time after implantation. RESULTS AND CONCLUSION:There were no significant differences in surgical time, out of bed time, postoperative hospitalization time between the two groups (P > 0.05), but the intraoperative blood loss was significantly lower in the observation group than the control group (P 0.05). The vertebral height loss and bone fusion rate had no difference between the two groups at 6 months after operation and at the last folow-up (P > 0.05). No adverse effects occurred in the two groups. These findings indicate that nano-hydroxyapatite/polyamide artificial bone has good clinical effects in anterior cervical fusion, and the treatment effect is equivalent to autologous iliac bone graft.

Fabrication and properties of nano-hydroxyapatite/poly(3-hydroxybutyrate) ultrafine-fibrous scaffolds for bone tissue engineering / 中国组织工程研究

BACKGROUND:Poly(3-hydroxybutyrate) is approved as its excel ent biocompatibility, biodegradability and piezoelectric properties, but there are also some deficiencies, such as high breakability and poor hydrophilicity. METHODS:Poly(3-hydroxybutyrate) was mixed with different mass percentages of nanohydroxyapatite (0, 10%, 20%and 30%) to prepare new composite fibrous scaffolds through electrospinning process. The microstructure, group composition, crystal ine phase distribution, thermal properties and surface wettability of the scaffolds were detected. RESULTS AND CONCLUSION:Under the scanning electron microscope, with the increase of nano-hydroxyapatite content, more and more nano-hydroxyapatite particles were distributed evenly on the composite fiber surface;the fiber surface was basical y covered with nano-hydroxyapatite particles at the content of 30%, and the roughness of the fiber surface also increased. Results from differential scanning calorimetry and X-ray diffraction showed that the nano-hydroxyapatite reduced the crystal inity of poly(3-hydroxybutyrate) and the crystal tacticity, and this phenomenon became more evident with the increase of nano-hydroxyapatite content. Additional y, the higher the content of nano-hydroxyapatite content, the lower the contact angle and the higher the hydrophily. These findings indicate that the nano-hydroxyapatite/poly(3-hydroxybutyrate) ultrafine-fibrous scaffold using electrospinning technology can effectively improve the surface wettability and crystal inity of the material as wel as the material hydrophily and brittleness, and the higher the content of nano-hydroxyapatite, the more obvious the effect.

Antimicrobial and sealant properties of nanohydroxyapatite as endodontic sealer / 中国组织工程研究

BACKGROUND:Depending on different pH values, nanohydroxyapatite materials have different purities, whether root canal sealers formed by which exert effects on antimicrobial resistance, root canal closure and apical histocompatibility has no reports. OBJECTIVE:To compare the antimicrobial and sealant properties of nanohydroxyapatite materials with different pH, nanohydroxyapatite-composite and traditional root canal sealants. METHODS:We detected the antimicrobial action of nanohydroxyapatite with pH 8, 9, 10, Vitapex and AH-Plus root canal sealants with and without addition of ornidazole against three microbial strains namely Enterococcus faecalis, Candida albicans and Staphylococcus aureus using agar diffusion method. And we also analyzed the endodontic microleakage of six root canal sealants by determining the apical reservoir glucose concentration using Glucose Oxidase Method. RESULTS AND CONCLUSION:Pure nanohydroxyapatite with different pH did not show antimicrobial properties. Addition of ornidazole to nanohydroxyapatite showed greater inhibitory action against Enterococcus faecalis, lesser in Staphylococcus aureus, fol owed by Candida albicans. Vitapex root canal sealer had inhibitory effects only against Staphylococcus aureus. AH-Plus, itself, had antimicrobial activity against al the three strains, but the antimicrobial activity decreased after addition of ornidazole. Nanohydroxyapatite, as a root canal sealant, was superior to zinc oxide eugenol and Vitapex, but inferior to AH-Plus. Addition of ornidazole to nanohydroxyapatite for a short period showed no impact on sealant properties of the material.

Preparation and properties of hydrophilic modified artificial bone scaffold using low-temperature rapid prototyping / 中国组织工程研究

BACKGROUND:Low-temperature rapid prototyping technology is a new kind of rapid prototyping technology, and it is rapidly used in the preparation of bone tissue engineering scaffolds because it can make scaffold forming control able and can keep the biological activity of the materials, also can easily realize the scaffold with porous of three-dimensional structure and other advantages. OBJECTIVE:To investigate the preparation process of polyethylene glycol-modified polylactic acid-glycolic acid/nano-hydroxyapatite (PLGA-PEG/n-HA) using the low-temperature rapid prototyping, and to test its performance. METHODS:PLGA-PEG/n-HA and PLGA/n-HA were prepared by low-temperature rapid prototyping equipment. Under an electron microscopy, we observed ultra-structure of the scaffolds. Immersion (ethanol) method was used to test the porosity, and electronic testing machine was used to determine the material mechanical properties. Then these two kinds of scaffolds with rat osteoblasts were cultured in vitro, the cel adhesion rate was detected by precipitation method after 12 hours, and cel counting kit-8 method was used to determine the cel proliferation at culture days 1, 3, 5, 7, 9, 12. RESULTS AND CONCLUSION:Both of the two scaffolds had ideal aperture range and high porosity. But the aperture range of PLGA-PEG/n-HA scaffolds had large fluctuations, and the average aperture was smal er than that of PLGA/n-HA. Some pores were closed up. The cel adhesion rate and the cel growth curve of PLGA-PEG/n-HA was better than that of PLGA/n-HA (P<0.05), but the mechanical properties were less than PLGA/n-HA (P<0.05). The results showed the PLGA-PEG/n-HA scaffolds had good cel compatibility.

Biocompatibility of rat osteoblasts with chitosan/hydroxyapatite composite scaffold degradation products / 中国组织工程研究

BACKGROUND:The in vivo degradation process of chitosan/hydroxyapatite composite porous scaffolds is not very clear. Research on the effects of rat osteoblasts and degradation products is less. OBJECTIVE:To analyze the biocompatiblity of rat osteoblasts with degradation products of chitosan/hydroxyapatite composite porous scaffolds. METHODS:The second generation of cultured rat osteoblasts were respectively cultured in the extract of degradation products of chitosan/hydroxyapatite composite scaffolds (experimental group) and Dulbecco’s modified Eagle’s medium containing 10%fetal bovine serum (control group). At 2, 4, 6, 8, 10 days of culture, cel counting was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Alkaline phosphatase activity was measured by the recommended method of determination of the Federation, and total protein was determined by BCA method. RESULTS AND CONCLUSION:The proliferation speed, alkaline phosphatase activity, total cel ular protein synthesis and ratio of alkaline phosphatase to total protein in rat osteoblasts cultured in the experimental group were significantly higher than those in the control group (P<0.05). This experiment showed that the degradation products of chitosan/hydroxyapatite composite porous scaffolds cannot only promote rat osteoblast adhesion, growth and proliferation, but also enhance its ossification function, with good biocompatibility.

Preparation and cytocompatibility of cuttlebone-transformed hydroxyapatite / 中国组织工程研究

BACKGROUND:Recently, bone tissue engineering is highlighted from the nature source. OBJECTIVE:To explore the preparation of a cuttlebone-transformed hydroxyapatite scaffold as the novel bone substitution. METHODS: As raw materials, the cuttlebone appeared to have a hydrothermal reaction with diammonium phosphate under specific conditions, and the hydrothermal products were characterized respectively by X-ray diffraction, Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy and scanning electron microscopy. RESULTS AND CONCLUSION:The results showed that the hydrothermal products were hydroxyapatite. The cuttlebone-transformed hydroxyapatite possessed good three-dimensional structure. Cytocompatibility of the cuttlebone-transformed hydroxyapatite with MG63 cels culturedin vitro were observed and we found the cuttlebone-transformed hydroxyapatite had no obvious effects on cellgrowth and no toxicity, which can be used as new bone tissue engineering scaffolds.

Efeito do trimetafosfato de sódio e do fluoreto sobre a solubilidade da hidroxiapatita: estudo in vitro / Effect of sodium trimetaphosphate and fluoride on hydroxyapatite solubility: an in vitro study

O objetivo deste estudo foi avaliar o efeito de diferentes concentrações de trimetafosfato de sódio (TMP) associado ao fluoreto (F) sobre a solubilidade da hidroxiapatita (HA), bem como as propriedades físicas e químicas da HA depois de um ciclo de pH. O pó de HA sintética (1,0 g; n= 6) foi misturado com soluções de TMP nas concentrações de 0; 0,1; 0,2; 0,4; 0,6; 0,8; 1,0; 2,0; 4,0; 6,0; 8,0 e 10%, associadas ao F nas concentrações de 0, 100, 250 e 500 ppm F, durante 2 min. A suspensão foi filtrada e o precitado foi seco por 24 horas a 37°C e moído. Depois do tratamento, as amostras de HA tratada foram submetidas a um ciclo de pH. As amostras de HA ciclada foram caracterizadas por energia dispersiva de raios-X (EDX), espectroscopia de infravermelho (FTIR) e difração de raios-X (DRX). Depois, as concentrações de F solúvel em base e em ácido, cálcio (Ca) e fósforo (P) foram determinadas na HA ciclada, assim como as concentrações de P e F no sobrenadante. Os dados de F, Ca, P e proporção molar Ca/P na HA, e F e P no sobrenadante foram submetidas à Análise de Variância e teste de Student-Newman-Keuls (p<0,05). Houve uma redução do tamanho dos cristais de HA com o aumento da concentração de TMP. A HA tratada com 500 ppm F e TMP a 1% produziu uma HA com cristalitos de tamanho maiores. O FTIR mostrou uma redução na intensidade das bandas de fosfatos e carbonato quando comparado à HA sintetizada. As maiores proporções Ca/P foram observadas na HA tratada com TMP entre 0,4% e 1% quando combinado com 250 ppm F, e entre 0,4% e 2% em associação com 500 ppm F (p<0,05). Um aumento na concentração de TMP levou a uma redução na incorporação de F solúvel em ácido na estrutura do cristal para todos os grupos, nas duas situações (depois do tratamento e depois do ciclo de pH) (p<0,05). Adicionalmente, um aumento na concentração de TMP também proporcionou uma maior adsorção de TMP à HA para as soluções de 0 e 100 ppm F, mas menor para as soluções de 250 e 500 ppm F (p<0,05)...

The aim of this study was to evaluate the effect of different concentrations of sodium trimetaphosphate (TMP) associated with fluoride (F) on hydroxyapatite (HA) solubility, as well as in chemical and physical properties of HA after a pH-cycle. Synthetic HA powder (1.0 g; n= 6) was mixed with solutions of TMP at 0, 0.1, 0.2, 0.4, 0.6, 0.8, 1.0, 2.0, 4.0, 6.0, 8.0 and 10%, associated with fluoride at 0, 100, 250 and 500 ppm F, during 2 min. The suspension was filtered and the precipitates were dried for 24 h at 37°C and grinded. After the treatment, HA samples were submitted to a pH-cycle. Post-cycled HA samples were analyzed by energy-dispersive X-ray spectroscopy (EDX), infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Afterwards, the concentration of alkali and acid soluble F, Ca and P were determined in post-cycled HA, as well as P and F in the supernatant. The data of F, Ca, P, Ca/P ratio of HA, and F and P in the supernatant were submitted to ANOVA and Student-Newman-Keuls’ test (p<0.05). A reduction of the size of the HA crystallites was seen with increasing TMP concentrations in the solutions. HA treated with 500 ppm F and 1% TMP produced an HA with crystallites of larger size. The FTIR showed a reduction in the bands corresponding to phosphates and to carbonate for all groups when compared to the HA synthetized. The highest Ca/P ratios were observed for HA treated with TMP concentrations between 0.4% and 0.8% when combined with 250 ppm F, and between 0.4% and 2% in association with 500 ppm F (p<0.05). The increase of TMP led a reduced acid-soluble F incorporation in HA for all groups, both immediately after treatment and after the pH cycle (p<0.05). Additionally, the increase in TMP concentrations led to higher P adsorption to HA for the 0 and 100 ppm F solutions, but lower for the 250 and 500 ppm F solutions (p<0,05). The results indicate that the mechanism of action of TMP seems to be related with the TMP adsorption to crystal structural...

Análise estrutural e bioquímica da hidroxiapatita submetida ao tratamento com fluoreto e polifosfatos / Structural and biochemical analysis of hydroxyapatite submitted to the treatment with fluoride and polyphosphates

Este estudo avaliou o efeito do trimetafosfato de sódio (TMP) e hexametafosfato de sódio (HMP) associados ou não ao fluoreto (F) na dissolução e estrutura da hidroxiapatita (HA). Para tanto, o estudo foi dividido em três subprojetos. Nos subprojetos 1 e 2, o pó de HA sintética (n=6) foi tratado com soluções contendo entre 0 e 10% de TMP associado a 0, 100, 250, 500 (Subprojeto 1) e a 0, 1100, 4500 e 9000 ppm F (Subprojeto 2), sendo submetido a um ciclo de pH. As concentrações de F alcáli- e ácido solúvel, cálcio (Ca) e fósforo (P) foram determinadas na HA, e as de P e F no sobrenadante. As amostras foram analisadas pela espectroscopia no infravermelho (FTIR), difração de Raios-X (DRX) e espectroscopia de energia dispersiva (EDX). No Subprojeto 3, discos de HA foram empregados para avaliar a taxa de dissolução da mesma utilizando o sistema pHstat. Estes foram tratados com soluções contendo 1100 ppm F, 1 e 8% de HMP ou TMP e 1100 ppm F associado com 1 e 8% de HMP ou TMP, totalizando 9 grupos (n=8). A influência da película salivar também foi avaliada. Discos de HA foram mantidos em saliva humana previamente ao tratamento com água deionizada e 1100 ppm F associado com 1 e 8% de HMP ou TMP, totalizando 5 grupos (n=8). A taxa de dissolução pós-tratamento foi determinada a partir de 3 medidas consecutivas a cada 30 min. Os dados foram submetidos a ANOVA, teste de Student-Newman-Keul’s e coeficiente de correlação de Pearson (Subprojetos 1 e 2) e a ANOVA e testes de Fisher e Holm-Sidak (Subprojeto 3) (α=0,05). Valores de proporção Ca/P maiores foram observados para as soluções fluoretadas quando comparados à solução sem F e TMP, sendo os mesmos dependentes da proporção F:TMP (p<0,05). A deposição do F álcali-solúvel foi diretamente relacionada com as concentrações de TMP nas soluções, enquanto que a de F ácido-solúvel foi inversamente relacionada (p<0,05). Além disso, a adsorção de P esteve relacionada à concentração de F e TMP (p<0,05)...

This study evaluated the effect of sodium trimetaphosphate (TMP) and sodium hexametaphosphate (HMP) associated or no with fluoride (F) on the structure and dissolution of hydroxyapatite (HA). For this purpose, the study was divided into three subprojects. In Subprojects 1 and 2, synthetic HA powder (n=6) was treated with solutions containing TMP varying at 0-10% associated with 0, 100, 250, 500 (Subproject 1) and 0, 1100, 4500 and 9000 ppm F (Subproject 2) and submitted to a pH cycle. Afterwards, alkali- and acid soluble F, Ca and P were determined in/on HA, and P and F in the supernatants. Samples were analyzed by infrared spectroscopy (FTIR), X-ray diffraction (XDR) and energy-dispersive X-ray spectroscopy (EDX). In Subproject 3, HA discs were used to assess the dissolution rate of HA using a pHstat system. HA discs were treated with 1100 ppm F, 1% and 8% of HMP or TMP and 1100 ppm F associated with 1% and 8% of HMP or TMP, totaling 9 groups (n=8). The influence of a salivary pellicle on HA dissolution was also assessed. HA discs were kept in pooled human saliva before treatment with deionised water and 1100 ppm F associated with 1% and 8% of HMP or TMP, totaling 5 groups (n=8). The post-treatment dissolution rate was determined from three consecutive 30-min assays. Data were submitted to ANOVA, Student-Newman-Keuls’ test and Pearson’s correlation coefficient (Subprojects 1 and 2), and to ANOVA and Fisher and Holm- Sidak methods (Subproject 3) (α=0.05). Ca/P ratios values were higher for the fluoride solutions when compared with the no F and TMP groups and dependent of the F:TMP ratio used (p<0.05). The overall trend was that alkali-soluble F deposition was directly related to TMP concentrations in the treatment solutions, while acid-soluble incorporation was inversely related to TMP concentrations (p<0.05). Additionally, the P adsorption is related to the F and TMP concentration used (p<0.05). XDR data indicated that HA powder crystallinity is altered...

Análise estrutural e bioquímica da hidroxiapatita submetida ao tratamento com fluoreto e polifosfatos / Structural and biochemical analysis of hydroxyapatite submitted to the treatment with fluoride and polyphosphates

Este estudo avaliou o efeito do trimetafosfato de sódio (TMP) e hexametafosfato de sódio (HMP) associados ou não ao fluoreto (F) na dissolução e estrutura da hidroxiapatita (HA). Para tanto, o estudo foi dividido em três subprojetos. Nos subprojetos 1 e 2, o pó de HA sintética (n=6) foi tratado com soluções contendo entre 0 e 10% de TMP associado a 0, 100, 250, 500 (Subprojeto 1) e a 0, 1100, 4500 e 9000 ppm F (Subprojeto 2), sendo submetido a um ciclo de pH. As concentrações de F alcáli- e ácido solúvel, cálcio (Ca) e fósforo (P) foram determinadas na HA, e as de P e F no sobrenadante. As amostras foram analisadas pela espectroscopia no infravermelho (FTIR), difração de Raios-X (DRX) e espectroscopia de energia dispersiva (EDX). No Subprojeto 3, discos de HA foram empregados para avaliar a taxa de dissolução da mesma utilizando o sistema pHstat. Estes foram tratados com soluções contendo 1100 ppm F, 1 e 8% de HMP ou TMP e 1100 ppm F associado com 1 e 8% de HMP ou TMP, totalizando 9 grupos (n=8). A influência da película salivar também foi avaliada. Discos de HA foram mantidos em saliva humana previamente ao tratamento com água deionizada e 1100 ppm F associado com 1 e 8% de HMP ou TMP, totalizando 5 grupos (n=8). A taxa de dissolução pós-tratamento foi determinada a partir de 3 medidas consecutivas a cada 30 min. Os dados foram submetidos a ANOVA, teste de Student-Newman-Keul’s e coeficiente de correlação de Pearson (Subprojetos 1 e 2) e a ANOVA e testes de Fisher e Holm-Sidak (Subprojeto 3) (α=0,05). Valores de proporção Ca/P maiores foram observados para as soluções fluoretadas quando comparados à solução sem F e TMP, sendo os mesmos dependentes da proporção F:TMP (p<0,05). A deposição do F álcali-solúvel foi diretamente relacionada com as concentrações de TMP nas soluções, enquanto que a de F ácido-solúvel foi inversamente relacionada (p<0,05). Além disso, a adsorção de P esteve relacionada à concentração de F e TMP (p<0,05). Os dados da DRX indicaram que...

This study evaluated the effect of sodium trimetaphosphate (TMP) and sodium hexametaphosphate (HMP) associated or no with fluoride (F) on the structure and dissolution of hydroxyapatite (HA). For this purpose, the study was divided into three subprojects. In Subprojects 1 and 2, synthetic HA powder (n=6) was treated with solutions containing TMP varying at 0-10% associated with 0, 100, 250, 500 (Subproject 1) and 0, 1100, 4500 and 9000 ppm F (Subproject 2) and submitted to a pH cycle. Afterwards, alkali- and acid soluble F, Ca and P were determined in/on HA, and P and F in the supernatants. Samples were analyzed by infrared spectroscopy (FTIR), X-ray diffraction (XDR) and energy-dispersive X-ray spectroscopy (EDX). In Subproject 3, HA discs were used to assess the dissolution rate of HA using a pHstat system. HA discs were treated with 1100 ppm F, 1% and 8% of HMP or TMP and 1100 ppm F associated with 1% and 8% of HMP or TMP, totaling 9 groups (n=8). The influence of a salivary pellicle on HA dissolution was also assessed. HA discs were kept in pooled human saliva before treatment with deionised water and 1100 ppm F associated with 1% and 8% of HMP or TMP, totaling 5 groups (n=8). The post-treatment dissolution rate was determined from three consecutive 30-min assays. Data were submitted to ANOVA, Student-Newman-Keuls’ test and Pearson’s correlation coefficient (Subprojects 1 and 2), and to ANOVA and Fisher and Holm- Sidak methods (Subproject 3) (α=0.05). Ca/P ratios values were higher for the fluoride solutions when compared with the no F and TMP groups and dependent of the F:TMP ratio used (p<0.05). The overall trend was that alkali-soluble F deposition was directly related to TMP concentrations in the treatment solutions, while acid-soluble incorporation was inversely related to TMP concentrations (p<0.05). Additionally, the P adsorption is related to the F and TMP concentration used (p<0.05). XDR data indicated that HA powder crystallinity is altered...