The impact of synthetic bone grafting for tissue regeneration: an in vivo study

Aims: This study aimed to examine the biological response of synthetic nanocomposite material on canine mandibular bone. Methods: Nine healthy adult male local breed dogs aged 12 to 18 months and weighing 10.2 to 15.2 kg were used in the study. Based on healing intervals of 1 and 2 months, the dogs were divided into 2 groups. Each group had 3 subgroups with 3 dogs each. The division was based on the grafting material used to fill the created defect: an empty defect (Control-ve), Beta-Tricalcium Phosphate, and nanocomposite (Beta-Tricalcium Phosphate and nanosilver 1%) . Surgery started after the dogs were anaesthetized. The surgical procedure began with a 5 cm parallel incision along the mandible's lower posterior border. After exposing the periosteum, a three 5mm-diameter, 5-mmdeep critical-size holes were made, 5mm between each one. Each group's grafting material had independent 3 holes. The defects were covered with resorbable collagen membranes followed by suturing of the mucoperiosteal flap. Results: Total densitometric analysis showed no significant differences between groups at 1-month intervals, with the nanocomposite group having a higher mean rank (165.66± 31.21) in comparison to other groups while at 2 months intervals that there was a highly significant difference between three groups as the P-value was (0.000) with the nanocomposite group having a higher mean rank (460.66± 26.40). Conclusions: In the current study, the use of nanocomposites improved osteoconductivity by accelerating new bone formation. Moreover, the encorporation of nanosilver enhanced growth factor activity. These attributes make nanocomposites a promising material for enhancing the bone healing process

Physico-chemical and biological properties of different magnesium modified calcium phosphate bone cements / 中华创伤杂志

Objective:To investigate the physicochemical and biological properties of different magnesium modified calcium phosphate bone cements.Methods:The different magnesium modified calcium phosphate bone cements were divided into magnesium citrate, magnesium lactate, magnesium malate, magnesium phosphate and magnesium glycinate groups, each of which was added with different magnesium agents in the proportion of 0%, 1%, 3% and 5% of the total weight of calcium phosphate bone cements. The initial and final setting time, injectability, anti-collapse performance and compressive strength of different magnesium modified calcium phosphate bone cements were tested. Furthermore, the screened bone cement extracts were used to culture with third generation osteoblasts. Bioactivity assays were performed using the Cell Proliferation and Toxicity Assay Kit (CCK-8). Alkaline phosphatase (ALP) staining and Alizarin Red S (ARS) staining were performed on osteoblasts to observe the osteogenic activity of magnesium malate modified calcium phosphate bone cements.Results:The addition of different proportions of different magnesium agents led to the shortening of the initial and final setting time of modified calcium phosphate bone cements. Moreover, the final setting time of 5% magnesium malate modified calcium phosphate bone cements was the shortest (<40 minutes), which was significantly shorter compared with other magnesium agents in the same proportion (all P<0.05). With the addition of different magnesium agents in different proportions, the injectability of bone cements was gradually increased, and the injectability of 5% magnesium malate calcium phosphate bone cements reached the highest for (87.3±1.9)%, which was significantly increased compared with other magnesium agents in the same proportion (all P<0.05). The anti-collapse performance of bone cements was decreased with the addition of different magnesium agents in different proportions. Magnesium citrate, magnesium phosphate and magnesium glycinate modified calcium phosphate bone cements could not resist the flushing of deionized water. In particular, magnesium malate modified calcium phosphate bone cements had the best anti-collapse performance, with the maximum weight loss rate for only (9.8±2.3)% after 30 minutes of deionized water flushing, which was better than the rest of the groups (all P<0.05). The compressive strength of magnesium lactate and magnesium phosphate modified calcium phosphate bone cements showed a decrease compared with original calcium phosphate bone cements, while the compressive strength of magnesium citrate and magnesium malate modified calcium phosphate bone cements was significantly increased compared with original calcium phosphate bone cements, of which 3% magnesium malate modified calcium phosphate bone cements had the greatest compressive strength of (6.2±0.2)MPa, significantly higher than the rest of the groups (all P<0.05). The sieve test yielded magnesium malate modified calcium phosphate bone cement, which had a weight loss of (27.0±0.9)% at 35 days in vitro. The release of magnesium ions was increased with increasing magnesium malate dose in the in vitro environment of magnesium malate modified calcium phosphate bone cements in different ratios. A stable magnesium ion release was achieved within 35 days.Also, the pro-proliferative and osteogenic effects of modified calcium phosphate bone cements on osteoblasts were more obvious with increase of magnesium malate dose. For 5% magnesium malate modified calcium phosphate bone cements, the cell number, ALP staining area ratio and calcium nodule area ratio were significantly increased compared with the groups in the proportion of 0% and 1% magnesium malate (all P<0.05). Conclusions:Among magnesium citrate, magnesium lactate, magnesium malate, magnesium phosphate and magnesium glycinate modified calcium phosphate bone cements, magnesium malate modified calcium phosphate bone cements have relatively suitable setting time, excellent anti-collapse performance and mechanical strength. Meanwhile, 5% magnesium malate modified calcium phosphate bone cements have better biological activity among different ratios of magnesium malate modified calcium phosphate bone cements, suggesting a potential value for clinical application.

Mechanical properties and surface roughness of polymer-based materials containing DCPD particles

Abstract The purpose of this study was to synthesize dicalcium phosphate dihydrate (DCPD) particles functionalized with triethylene glycol dimethacrylate (TEGDMA) through different routes by varying the receptor solution: ammonium phosphate (AP groups) or calcium nitrate (CN groups) and the moment in which TEGDMA was incorporated: ab initio (ab) or at the end of dripping the solution (ap). Two syntheses were performed without adding TEGDMA (nf). The particles were characterized by X-ray diffractometry, true density (using a helium pycnometer), surface area, and scanning electron microscopy. A 20 vol% of DCPD particles from the D, E, and F groups was added to the resin matrix to determine the degree of conversion (DC), biaxial flexural strength (BFS), the flexural modulus (FM), and surface roughness after an abrasive challenge (RA). A group with silanized barium glass particles was tested as a control. The data were submitted to ANOVA/Tukey's test (DC, BFS, and RA), and the Kruskal-Wallis test (FM) (alpha = 0.05). BFS values varied between 83 and 142 MPa, and the CN_ab group presented a similar value (123 MPa) to the control group. FM values varied between 3.6 and 8.7 GPa (CN_ab and CN_nf groups, respectively), with a significant difference found only between these groups. RA did not result in significant differences. The use of calcium nitrate solution as a receptor, together with ab initio functionalization formed particles with larger surface areas. Higher BFS values were observed for the material containing DCPD particles with a higher surface area. In general, the DC, FM, and RA values were not affected by the variables studied.

Surface and mechanical properties of adhesives with calcium phosphates challenged to different storage media

Aim: To evaluate the behavior of experimental dental adhesives with hydroxyapatite (HAp), alpha-tricalcium phosphate (α-TCP) or octacalcium phosphate (OCP) after storing them in three different media: dry storage, distilled water, or lactic acid. Methods: An experimental adhesive resin was formulated with bisphenol A glycol dimethacrylate, 2-hydroxyethyl methacrylate, and photoiniciator/co-initiator system. HAp(GHAp), α-TCP (Gα-TCP), or OCP (GOCP) were added to the adhesive resin at 2 wt.%, and one group remained without calcium phosphates to be used as a control (GCtrl). The adhesives were evaluated for surface roughness, scanning electron microscopy (SEM), and ultimate tensile strength (UTS) after storing in distilled water (pH=5.8), lactic acid (pH=4) or dry medium. Results: The initial surface roughness was not different among groups (p>0.05). GHAp showed increased values after immersion in water (p<0.05) or lactic acid (p<0.05). SEM analysis showed a surface variation of the filled adhesives, mainly for Gα-TCP and GHAp. GHApshowed the highest UTS in dry medium (p<0.05), and its value decreased after lactic acid storage (p<0.05). Conclusions: The findings of this study showed that HAp, OCP, and α-TCP affected the physical behavior of the experimental adhesive resins in different ways. HAp was the calcium phosphate that most adversely affected the surface roughness and the mechanical property of the material, mainly when exposed to an acid medium

An in Vitro Evaluation of Remineralizing Capacity of Self-Assembling Peptide (SAP) P11-4 and Casein Phosphopeptides-Amorphous Calcium Phosphate (CPP-ACP) on Artificial Enamel

Objective: To determine and compare the remineralizing capacity of self-assembling peptide (SAP) P11-4 and casein phosphopeptides­amorphous calcium phosphate (CPP-ACP) on enamel. Material and Methods: Enamel samples were divided into 2 groups. Group I was treated with Self­assembling peptide (SAP) P11-4 and group II with casein phosphopeptides-amorphous calcium phosphate (CPP-ACP). In both groups, remineralizing capacity was assessed at baseline, 2 weeks, 6 weeks and 12 weeks. Student's t- test and ANOVA were applied, with the significance level set at 5%. Results: The mean calcium weight % was evaluated at baseline, 2 weeks, 6 weeks and 12 weeks. In Group I, there was increase in mean value (62.12 ± 1.24) from baseline to 12 weeks (67.36 ± 2.14). However, there was decrease in phosphate weight % from 37.16 ± 2.52 at baseline to 35.72 ± 2.11 at 12 weeks. In Group II, mean calcium weight % was 64.18 ± 1.52 at baseline, which ultimately increased to 66.01 ± 2.03 at 12 weeks. Phosphate weight % showed reduction from 37.34 ± 2.23 at baseline to 35.04 ± 2.02 at 12 weeks. Ca/P ratio showed significant improvement. There was significant difference in Ca/P ratio at 2 weeks, 6 weeks and 12 weeks in both groups (p<0.05). Conclusion: Self-assembling peptide (SAP) P11-4 found to be more effective and efficient as compared to casein phosphopeptides­amorphous calcium phosphate (CPP-ACP).

Comparative Evaluation of Remineralizing Potential of a Paste Containing Bioactive Glass and a Topical Cream Containing Casein Phosphopeptide-Amorphous Calcium Phosphate: An in Vitro Study

Objective: To evaluate and compare the remineralization potential of a dentifrice containing bioactive glass and a topical cream containing casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) in remineralizing artificial carious lesion on enamel. Material and Methods: Forty-five freshly extracted human permanent premolar teeth were selected. Samples were divided into three groups: GI - regular tooth paste without specific remineralizing agent; GII - tooth paste containing calcium sodium-phosphosilicate (novamin) and GIII - topical cream containing casein phosphopeptide-amorphous calcium phosphate. All the sound enamel samples were viewed under scanning electron microscope (SEM) to assess the topographical pictures of enamel surface and energy dispersing x-ray analysis (EDAX) was done to estimate quantitatively the amounts of mineral (calcium and phosphorous). The mineral content of calcium and phosphorus after demineralization in each group was noted. The samples were then subjected to SEM and EDAX. Results: GI does not show any increase in the calcium and phosphorus after applying toothpaste without any remineralizing agent but GII and GIII showed a net increase in calcium and phosphorous values after applying concern-remineralizing agents. Inter group comparison showed GIII yield higher net calcium and phosphorous values than GII. Conclusion: Two remineralizing agents showed remineralization potential on enamel surfaces. Casein phosphopeptide-amorphous calcium phosphate showed better remineralizing potential than calcium sodium phosphosilicate. Hence CPP-ACP can be considered as the material of choice in remineralizing early enamel carious lesions.

The Ability of Biodentine™ of Guided Tissue Remineralization (GTR): Analysis Using SEM, EDX and TEM

Objective: To analyze the Biodentine™ capability in guided tissue remineralization. Material and Methods: Four premolar with two cavities per tooth of 3 mm depth were demineralized with EDTA 17% in shaking incubator at 37°C temperature. After 7 days, the sample were washed with aquabidest then were soaked in 20 ml NaCl 1 M (pH 7.0) at 25°C temperature for 8 hours. The samples were divided into two groups: G1: The control group (cavity directly restored with composite resin); G2: Biodentine™ group (cavity with Biodentine™ as a base then restored with composite resin). All samples were stored in shaking incubator under PBS solution at 37°C temperature. SEM, EDX and TEM analysis were performed on the 7th and 14th day. Results: The 14th day Biodentine group had the best SEM remineralization feature with irregular dentine tubular features covered by density of mass. In the EDX analysis, the concentration of calcium ion of the Biodentine group was higher than the control group on the 7th day analysis (Biodentin™ 10.2167 and control 1.9667) and on the 14th day analysis (Biodentine™ 29.833 and Control 22.080). The Biodentine™ group and control group of the 7th and 14th day experienced significant increases in calcium ion concentration while the concentration of phosphate ion in the Biodentine™ and control group had a much lower value of calcium either on the 7th or 14th day. The TEM analysis of Biodentine™ group showed more intrafibrillar remineralization than the control group. The feature of intrafibrillar dentin remineralization is analyzed by looking at the density of black dots in collagen. Conclusion: Biodentine™ is able to trigger the process of remineralization by guided tissue remineralization.

Patent analysis for calcium phosphate bone cements / 中国组织工程研究

BACKGROUND: Calcium phosphate bone cement exhibits great commercial potential as bone filling materials in the field of clinical biomedical engineering; however, due to some existing technical and theoretical challenges, its wide spread application is hindered. It is therefore necessary to search existing patents to explore various potential improvements in modification of calcium phosphate bone cement. OBJECTIVE: To analyze the patent information of calcium phosphate bone cement for better understanding of the development of the calcium phosphate bone cement technology, and for early warning of patent infringement.METHODS: Based on the manual screening of Incopat patent database, we analyzed 2 711 patent documents from four aspects — the application trend, patent layout, competitor analysis, and efficacy matrix. In combination with technology development and industrialization, this paper also shows some important Chinese patents selectively. RESULTS AND CONCLUSION: The United States is in the leading position in the calcium phosphate bone cement field, while this technology is developing rapidly in China. Various components and methods are developed for modifying calcium phosphate bone cement, which are the focus of patent development and layout. Although some of the fundamental patents have expired, patent infringement risks need to be tested and mitigated for the development and industrialization by Chinese enterprises as there are some important patents in China arranged by foreign companies. At the same time, Chinese patent holders need to master international patent layout and develop their intellectual properties for the future international marketplace.

Three-dimensional printing beta-tricalcium phosphate scaffold loaded with icariin particles for repairing osteonecrosis of the femoral head in rabbits / 中国组织工程研究

BACKGROUND: Preliminary study has prepared three-dimensional printing β-tricalcium phosphate scaffold loaded with icariin. OBJECTIVE: To investigate the role of three-dimensional printing β-tricalcium phosphate scaffold loaded with icariin in the repair of rabbit models of osteonecrosis of the femoral head. METHODS: New Zealand white rabbits (provided by Qinglongshan Laboratory Animal Center of Nanjing) were selected to establish the steroid-induced osteonecrosis of the femoral head. The 27 model rabbits underwent core decompression and debridement, were randomly divided into three groups, and then implanted with autologous bone, β-tricalcium phosphate scaffold, three-dimensional printing β-tricalcium phosphate scaffold loaded with icariin (composite scaffold group) , respectively. The micro-CT scanning and pathological observation were performed at 4, 8, and 12 weeks after implantation. RESULTS AND CONCLUSION: (1) Micro-CT showed that at 4 weeks after implantation, trabecular bone was observed around and in implants in each group. In the autologous bone group, there were a large number of trabecular bones in the grafting area at 8 weeks, and the trabecular bone structure was dense at 12 weeks after implantation. In the tricalcium phosphate and composite scaffold groups, the scaffolds were well integrated with the bone interface. At 4 weeks after implantation, there was a certain amount of trabecular bone surrounding the scaffold, and trabecular grew into the scaffold until 8 weeks in the composite scaffold group. At 4 weeks after implantation, few thin trabecular bone was visible, and extensive trabecular bone formation was observed around the scaffold at 8 weeks in the tricalcium phosphate group. (2) Hematoxylin-eosin staining results showed that there were many mature osteoblasts, and few cartilage matrix, newly born bones integrated well to the implants at 12 weeks in the autologous bone and tricalcium phosphate groups. In the composite scaffold group, there were many cartilage matrixes, and newly born bones integrated poorly to the implants. (3) Masson staining showed that at 12 weeks after implantation, the osteogenic capacity in the composite scaffold group was lower than that in the autologous bone group (P < 0.05) , but higher than that in the tricalcium phosphate group (P < 0.05) . (4) TRAP staining results at 12 weeks after implantation revealed that the amount of osteoclast in composite scaffold group was less than that in the tricalcium phosphate group (P < 0.05) , and was not significantly different from the autologous bone group (P> 0.05) . (5) Immunohistochemical staining at 12 weeks after implantation revealed that the positive rate of vascular endothelial growth factor in the composite scaffold group was higher than that in the tricalcium phosphate group (P < 0.05) , and lower than that in the autologous bone group (P < 0.05) . (6) In summary, three-dimensional printing β-tricalcium phosphate scaffold loaded with icariin implanted into the rabbit model of osteonecrosis of the femoral head can promote the proliferation and differentiation of osteoblasts, inhibit the viability of osteoclasts, promote the angiogenesis, and contribute to the repair of osteonecrosis of the femoral head in rabbits.

Calcium phosphate cement/fibrin glue composite loaded with recombinant human bone morphogenetic protein 2 promotes osteoporotic fracture healing / 中国组织工程研究

BACKGROUND: Bone morphogenetic protein 2 is a most widely studied and osteogenic-inducing bone morphogenetic protein. However, simple bone morphogenetic protein can be diluted by tissue fluid and decomposed by protease after implantation, so it is difficult to maintain sustained drug concentration or play an effective role in bone induction. OBJECTIVE: To observe the effect of repairing osteoporotic fracture through calcium phosphate cement/fibrin glue composite as the carrier of bone morphogenetic protein 2. METHODS: Fifty-four female Sprague-Dawley rats were selected to remove bilateral ovaries for making osteoporosis models. Three months later, the middle femoral fracture models were made, and then randomized into three groups, with 18 rats in each group. Kirschner wire fixation group was injected nothing. The fracture end was injected with 0.5 mL calcium phosphate cement/fibrin glue (composite group) or calcium phosphate cement/fibrin glue loaded with recombinant human bone morphogenetic protein 2 (loaded group) . At 4 and 12 weeks after fracture, X-ray examination, micro-CT examination, biomechanical three-point bending test and pathological observation were performed. RESULTS AND CONCLUSION: (1) The fracture healing score in the loaded group was higher than that in the other two groups (P < 0.05) . (2) The bone volume fraction, trabecular thickness and number of trabeculae at 4 and 12 weeks in the loaded group were higher than those in the other two groups (P < 0.05) , and the trabecular segregation was lower than that in the other two groups (P < 0.05) . (3) The maximum load and stiffness at 4 and 12 weeks in the loaded group were higher than those in the other two groups (P < 0.05) , and the elastic modulus at 4 weeks after fracture was higher than that in the other two groups (P < 0.05) . (4) Fibrocartilage callus was mainly seen at 4 weeks after fracture in the Kirschner wire fixation group, and the callus was reconstructed into lamellar bone at 12 weeks after fracture with less callus content. Obvious fibrocartilage callus appeared at 4 weeks after fracture in the composite and loaded groups, and the callus was reconstituted into a plate-like bone at 12 weeks. (5) These results imply that the calcium phosphate cement/fibrin glue composite loaded with recombinant human bone morphogenetic protein 2 can promote the healing of osteoporotic fracture and improve bone strength.

Avaliação de duas formas de hidroxiapatita e beta-tricálcio fosfato em enxertos sinusais com concomitante instalação de implantes em coelhos / Evaluation of two formulations of hydroxyapatite and beta-tricalcium phosphate in rabbit sinus grafts with concomitant implant placement

Este trabalho teve por objetivo avaliar o tecido ósseo periimplantar formado após o enxerto sinusal com hidroxiapatita e beta-tricálcio fosfato (HA + ß-TCP), nas apresentações em grânulos e em pasta, concomitante à instalação de implantes em coelhos. Trinta e quatro seios maxilares de coelhos foram enxertados com HA + ß-TCP, sendo metade do grupo grânulos e metade do grupo pasta. Concomitantemente, foi realizada a instalação de implantes. Aos 7 e 40 dias pósoperatórios, realizou-se a eutanásia dos animais, e as amostras foram preparadas para as análises tomográfica, microtomográfica, histológica (coloração por hematoxilina e eosina - HE), imunoistoquímica (marcação de fator de transcrição Runt-2 ­ RUNX2 ­, fator de crescimento endotelial vascular ­ VEGF ­, osteocalcina ­ OCN ­ e fosfatase ácida resistente ao tartarato ­ TRAP) e de torque de remoção dos implantes. Na tomografia, foi observada a manutenção da integridade da membrana sinusal, sem extravasamento de material, nos dois grupos e períodos. Parâmetros morfométricos de volume ósseo, porcentagem do volume ósseo e número de trabéculas foram significativamente superiores para o grupo pasta do que para o grupo grânulos aos 7 dias, enquanto que a porosidade foi maior para o grupo grânulos nesse mesmo período. Aos 40 dias, não houve diferença significativa entre os grupos para a maioria dos parâmetros microtomográficos estudados. Nos cortes histológicos corados por HE, observou-se que em ambos os grupos ocorreu a formação de tecido ósseo junto às espiras do implante aos 40 dias, favorecendo a osseointegração. Imunomarcações positivas semelhantes foram encontradas tanto para o fator de diferenciação osteoblástica RUNX2 quanto para o fator de mineralização OCN no osso neoformado nos dois grupos experimentais. A atividade osteoclástica evidenciada pela TRAP mostrou-se semelhante nos dois grupos, com discreto predomínio para o grupo grânulos. Já a marcação positiva para o VEGF mostrou-se aumentada no grupo grânulos, caracterizando um potencial osteocondutor superior nessa apresentação do biomaterial. Ademais, não houve diferenças nos valores de torque de remoção do implante entre ambos os grupos. Logo, as duas apresentações da HA + ß-TCP mostraram resultados favoráveis à osseointegração a longo prazo, com formação de tecido ósseo em quantidade e qualidade semelhantes junto aos implantes(AU)

This work aimed to evaluate the peri-implant bone tissue after maxillary sinus grafting with hydroxyapatite and beta-tricalcium phosphate (HA + ß-TCP), in granular and paste formulations, concomitant with implant placement in rabbits. Thirty four rabbit maxillary sinuses were grafted with HA + ß-TCP, being half of the granular group and half of the paste group. Concomitantly, the implant placement was performed. At 7 and 40 postoperative days, animals were euthanized, and the samples were prepared for tomographic, microtomographic, histological (hematoxylin and eosin staining), immunohistochemical (Runt-related transcription factor 2 ­ RUNX2, vascular endothelial growth factor ­ VEGF ­, osteocalcin ­ OCN ­ and tartrate-resistant acid phosphatase ­ TRAP ­ staining) and implant torque removal analyses. In computed tomography, the maintenance of sinus membrane integrity, with no material extravasation, was observed in both groups and periods. Morphometric parameters of bone volume, percentage of bone volume and trabecular number were significantly higher for paste than granular group at day 7, while the porosity was higher for granular group in this period. At day 40, there were no significant differences between both groups for the majority of the microtomographic parameters studied. In the HE-stained histological sections, it was observed that bone healing around implant threads occurred for both groups at day 40, enhancing osseointegration. Similar positive immunostainings were observed for both the RUNX2 osteoblastic differentiation factor and the OCN mineralization factor in the neoformed bone in the two experimental groups. The osteoclast activity evidenced by TRAP was similar in both groups, with a slight predominance for the granular group. Positive staining for VEGF growth factor was increased in the granular group, characterizing a superior osteoconductive potential for this biomaterial formulation. Besides, there were no differences in the values of implant removal torque between both groups. Thus, the two formulations o H + ß-TCP showed favorable osseointegration results in the long term, with similar amount and quality of bone tissue formation around the implants(AU)

Calcium phosphate crystals promotes vascular calcification through BMP-2/Smad signaling / 中华肾脏病杂志

Objective To investigate the role of BMP-2/Smad signaling pathway in the osteogenic differentiation of human aortic smooth muscle cells (HASMCs) caused by hyperphosphatemia -induced calcium phosphate (CaP) crystals.Methods High-phosphate medium was incubated at 37℃ for 3 days.CaP crystals and supernatant were isolated by ultracentrifugation.Scanning electron microscope and energy dispersive X-ray spectroscopy were performed for analysis of physicochemical characteristics of CaP crystals.HASMCs were cultured in vitro,and divided into high-phosphate,control,crystals and supernatant groups.Calcification was visualized by Alizarin red staining.Calcium loads in cells were quantified by o-cresolphthalein complexone method.Protein expression of bone morphogenetic protein-2 (BMP-2),Runt-related transcription factor 2 (RUNX2),osteopontin (OPN),phospho-Smad1/5/9 (p-Smad1/5/9) were quantified by Western blotting.After knockdowns of BMP-2 and Smad1 with small hairpin RNA (shRNA) interfering respectively in HASMCs,protein expressions were measured by Western blotting.Results High-phosphate medium induced the formation of CaP crystals.Compared with the cells in control group,CaP crystals significantly induced HASMCs calcification,increased calcium loads and up-regulated the levels of BMP-2,RUNX2 and OPN proteins (all P ＜ 0.05).After the addition of CaP crystals into HASMCs,the level of p-Smad 1/5/9 protein peaked at 30 min (P ＜ 0.05).After BMP-2 was knocked down in HASMCs,the expression of p-Smad1 caused by CaP crystals was blocked completely,and the expressions of RUNX2 and OPN caused by CaP crystals were reduced significantly (all P ＜ 0.05).After Smad1 was knocked down in HASMCs,the expressions of RUNX2 and OPN caused by CaP crystals were decreased significantly (all P ＜ 0.05).Conclusions Hyperphosphatemia-induced CaP crystals promoted osteogenic differentiation of HASMCs through the BMP-2/Smad signaling pathway.

A two-step reaction to prepare a fast-hardening strontium-calcium phosphate scaffold in room temperature / 中华创伤骨科杂志

Objective To evaluate a fast-hardening strontium-calcium phosphate scaffold using a two-step reaction in room temperature.Methods The original powder phase consisted of tetracalcium phosphate (TTCP),dicalcium phosphate anhydrous (DCPA) and strontium hydrogen phosphate (DSPA).The liquid phase consisted of 20wt％ citric acid and 12wt％ polyvinylpyrrolidone K-30.Groups were designed as Sr-0,Sr-5,Sr-10,and Sr-20,according to the molar ratios of Sr/(Sr + Ca) being 0,5％,10％,and 20％ in the powder phase,respectively.The ratio 0.5 mL/g in the liquid to solid phase was used for mixing.After the scaffold was prepared,its setting time,compression strength,phase composition and structural morphology,ions release and pH value of the substrates were analyzed.Results Addition of citric acid accelerated the setting reaction.Acceptable setting time was achieved by optimizing composition of the original powder and liquid phases.On the other hand,the compression strength,phase composition and structural morphology were not affected by addition of strontium.In addition,calcium and strontium ions were detected in the substrates,without any significant change in the pH value.Conclusion This two-step reaction can be used to prepare a fast hardening strontium-calcium phosphate scaffold in room temperature.

In vitro effect of amorphous calcium phosphate paste applied for extended periods of time on enamel remineralization

Abstract Dental applications based on the unique characteristics of amorphous calcium phosphate stabilized by casein phosphopeptides (CPP-ACP) have been proposed, as well as the improvement of its properties. Objectives: The objective of this study was to determine the ability of topically applied CPP-ACP from a commercial product to remineralize subsurface lesions when applied for extended periods of time (3 h and 8 h). Material and Methods: Artificially induced carious lesions were produced in 50 bovine enamel blocks previously selected by surface hardness. After treatments with gel without F and CPP-ACP applied for 1 minute (Placebo); 2% NaF neutral gel applied for 1 minute (Fluoride 1 min); CPP-ACP applied for 3 min (ACP 3 min); and CPP-ACP applied for 3 h (ACP 3 h) and for 8 h (ACP 8 h), the enamel blocks were submitted to the remineralization pH-cycling. Surface hardness and synchrotron micro-tomography were used to determine the percentage of surface hardness recovery (%SHR) and to calculate mineral concentration (gHAp.cm−3), respectively. The data were submitted to ANOVA followed by the Student-Newman-Keuls test (p<0.05). Results: Fluoride gel presented higher %SHR followed by ACP 3 min (p<0.001). No difference (p = 0.148) was found for Placebo, ACP 3 h and ACP 8 h groups for %SHR. Fluoride gel showed greater mineral concentration (p<0.001) when compared with the other groups. ACP 3 min demonstrated a significant difference (p<0.001) from ACP 3 h and ACP 8 h. The ACP 3 h and 8 h presented a subsurface lesion with development of laminations in all blocks. Conclusion: In this in vitro study the use of CPP-ACP for extended periods of time did not produce an additive effect in the remineralization process.

Trends in restorative composites research: what is in the future?

Abstract Clinical trials have identified secondary caries and bulk fracture as the main causes for composite restoration failure. As a measure to avoid frequent reinterventions for restoration replacement, composites with some sort of defense mechanism against biofilm formation and demineralization, as well as materials with lower susceptibility to crack propagation are necessary. Also, the restorative procedure with composites are very time-consuming and technically demanding, particularly concerning the application of the adhesive system. Therefore, together with bulk-fill composites, self-adhesive restorative composites could reduce operator error and chairside time. This literature review describes the current stage of development of remineralizing, antibacterial and self-healing composites. Also, an overview of the research on fiber-reinforced composites and self-adhesive composites, both introduced for clinical use in recent years, is presented.

Síntesis de monetita pura por reacción heterogénea ácido-base / Synthesis of pure monetite by heterogeneous acid-base reaction / Síntese de monetita pura por reação heterogênea ácido-base

Resumen Se estudiaron cinco variaciones del procedimiento de síntesis de monetita modificando la agitación, la velocidad de adición de acido fosfórico, la homogenización y la temperatura de secado. Los productos se caracterizaron por difracción de rayos X (DRX), microscopia electrónica de barrido (SEM-EDS), relación Ca/P (por titulación de calcio con permanganato de potasio y valoración colorimétrica de fósforo por la formación del complejo azul de molibdeno) y espectroscopia infrarroja con transformada de Fourier (FTIR). Los resultados de DRX, espectroscopia infrarroja y la relación Ca/P señalan que el fosfato sintetizado corresponde a monetita pura. Se encontró que los factores de síntesis que más afectan las propiedades de composición, estructura cristalina, relación Ca/P y forma y tamaño de grano de los fosfatos sintetizados son la relación estequiométrica de los reactantes y la mecanoactivación de sólido con sobrenadante.

Abstract Five variations of the monetite (M) synthesis were evaluated modifying the stirring, the phosphoric acid addition rate, the homogeneity and the drying temperature. Products were assessed by means of XRD, FTIR, SEM-EDS analysis and chemical assay of Ca/P (calcium by titration with potassium permanganate and phosphorus by colorimetric assessment of the molybdenum blue complex). X-ray diffraction, infrared spectroscopy and Ca/P ratio indicate that the synthesized phosphate corresponds to pure monetite. It was found that the most influential factors affecting grain composition, crystal size, shape and structure as well as Ca/P molar ratio of synthesized phosphates were stoichiometry and ballmilling mechanoactivation.

Resumo Foram estudadas cinco variações do método de síntese de monetita (M) modificando a agitação, a velocidade de adicáo do acido fosfórico, a homogeneização e a temperatura de secagem. Os produtos foram caracterizados por difratometria de raios X (DRX), microscopia eletrônica de varredura (SEM-EDS), relação Ca/P (Titulação de cálcio com permanganatode potassio e titulação de fósforo pela avaliação colorimetrica do complexo azul de molibdenio), e espectrometria no infra-vermelho com transformada de Fourier (FTIR). Os resultados de DRX, FTIR e relação Ca/P indicam que o fosfato sintetizado corresponde a monetita pura. Foi encontrado que os fatores de sintese que mais afeitam as propriedades da composição, estrutura cristalina, relação Ca/P e a forma e tamanho de grão dos fosfatos sintetizados são a proporção estequiométrica e a mecânoativação do solido com o sobrenadante.

Effect of two desensitizing agents on dentin permeability in vitro

Abstract Objective The aim of this in vitro study was to investigate the effect of two desensitizing agents and water on hydraulic conductance in human dentin. Material and Methods GLUMA Desensitizer PowerGel (GLU) contains glutaraldehyde (GA) and 2-hydroxyethyl methacrylate (HEMA), and Teethmate Desensitizer (TD) is a powder comprising tetracalcium phosphate (TTCP) and dicalcium phosphate anhydrous (DCPA) that is mixed with water. Deionized water was used as a negative control (CTR). Thirty discs with a thickness of 1.2 mm were cut from the coronal dentin of the third molars and cleaned with 0.5 M EDTA (pH 7.4). After being mounted in a split-chamber device, the discs were pressurized with water at 1 kPa and 3 kPa in order to measure flow rates with a highly sensitive micro-flow sensor and to calculate hydraulic conductance as a baseline value (BL). Following the application of GLU, TD, and CTR (n=10), hydraulic conductance was remeasured with intermittent storage in water after 15 min, 1 d, 1 w, and 1 m. Reduction in permeability (PR%) was calculated from hydraulic conductance. Data were statistically analyzed using nonparametric methods (α<0.05). Representative discs were inspected by SEM. Results PR% for GLU and TD were 30-50% 15 min and 1 m after their application. Post hoc tests indicated that PR% of CTR was significantly greater than those of GLU and TD at all time points tested. The PR% of GLU and TD were not significantly different. SEM examinations showed noncollapsed collagen meshes at the tubular entrances after GLU, and crystalline precipitates occluding the tubular orifices after TD, whereas CTR specimens showed typical patterns of etched dentin. Conclusions The present study on hydraulic conductance in dentin discs treated with two chemically different desensitizing agents and water as a control demonstrated that both products may be characterized as effective.

Reconstrução alveolar por aumento do assoalho do seio maxilar com beta-tricálcio fosfato ou osso autógeno para reabilitação com prótese implantossuportada / Alveolar reconstruction by enlargement of the maxillary sinus floor with beta-tricalcium phosphate or autogenous bone for rehabilitation with implantsupported prosthesis

A altura insuficiente do osso alveolar é um fator limitante para a reabilitação oral com próteses implantossuportadas. Taxas de sucesso clínico com uso de biomateriais à base de beta-tricálcio fosfato (b-TCP) para elevação do assoalho do seio maxilar (EASM) mostraram que são excelentes alternativas ao osso autógeno (OA). Portanto, objetivo foi avaliar a formação óssea do enxerto de b-TCP em bloco, seis meses após EASM, comparada ao OA por meio de análises tomográfica, microtomográfica e histomorfométrica. Para isso, Oito seios maxilares foram enxertados com b-TCF e sete OA. Após 6 meses, foram obtidas biópsias durante à instalação de implantes dentários. Não houve diferença significante (ANOVA) entre a contração do volume dos seios maxilares preenchidos por OA e b-TCP (p=0,113), bem como para todos os parâmetros microtomográfico (ANOVA) BV/TV (p=0.089), Tb.Th (p=1.000), Tb.Sp (p=0,989) e Tb.N (p=0.917). Na histomorfometria quando comparada a porcentagem ósseo em OA e b-TCP também não foi encontrada diferença estatística (ANOVA, p=0,794). Em conclusão, os resultados deste estudo indicam que ambos OA e b-TCP são adequados para o uso com segurança para o procedimento de EASM pela técnica da janela lateral. O material sintético apresenta boa estabilidade volumétrica com formação óssea semelhante ao OA suportada pelos parâmetros em análises 2D e 3D que se complementam. No entanto, a metodologia da análise volumétrica utilizada neste estudo parece representar a estabilidade volumétrica geral do procedimento, não somente do biomaterial, quando na técnica for utilizado o enxerto em bloco e não particulado(AU)

The insufficient height of the alveolar bone is a limiting factor for oral rehabilitation with implants. Clinical success rates using beta-tricalcium phosphate (b-TCP) biomaterials for maxillary sinus floor elevation (MSFE) have been shown to be excellent alternatives to autogenous bone (AB). Therefore, the objective was to evaluate bone formation of the b-TCP graft in a block, six months after MSFE, compared to AB by means of tomographic, microtomographic and histomorphometric analyzes. For this, eight maxillary sinuses were grafted with b-TCF and seven AB. After 6 months, biopsies were obtained during the installation of dental implants. There was no significant difference (ANOVA) between the volume contraction of the maxillary sinus filled by AB and b-TCP (p = 0.113), as well as for all microtomographic parameters (ANOVA) BV/TV (p = 0.089), Tb.Th (p = 1.000), Tb.Sp (p = 0.989) and Tb.N (p = 0.917). In histomorphometry, when comparing bone percentage in AB and b-TCP, no statistical difference was found (ANOVA , p = 0.794). In conclusion, the results of this study indicate that both AB and b-TCP are suitable for safe use for the MSFE procedure by the side window technique. The synthetic material presents good volumetric stability with bone formation similar to AB supported by the parameters in 2D and 3D analyzes that complement each other. However, the volumetric analysis methodology used in this study seems to represent the general volumetric stability of the procedure, not only of the biomaterial, when in graft and non-particulate graft technique(AU)

Evaluation of an experimental remineralizing agent for repairing enamel surfaces / Evaluación de un agente remineralizante experimental reparador de superficie de esmalte

The best material for repairing enamel surface defects is one very similar to the original enamel and which interacts with natural remineralization mechanisms. It does not repair extensive damage, so in order to fill large defects,external help is required using phosphocalcic ceramic composites that activate salivary remineralization efficiently though on smaller in scale. Effective adhesion of the repair may depend on the amount of aqueous fluids present in the enamel, which apparently enable nucleation and growth of new minerals to ensure adhesion and stability. The amount of fluids is governed by osmotic pressure. This study evaluated the influence of two osmotic pressure values of isotonic and hypotonic saliva and two modified remineralizing agent compositions: combinations of "conditioner" and "remineralizing agent" in proportions of 90%: 10% (A) and 50%: 50%(B), on filling artificial cracks. Results were evaluated by profilometer, stereomicroscope and confocal laser microscope. A 22 factorial design and a logistic model for statistical analysis were used. Only the composition of the mineralizing agent had a significant effect on efficiency in repairing defects. Compositions A and B both repaired dental enamel defects, but composition B presented higher levels of repair and more compact deposits as observed under stereomicroscope (AU)

El mejor material para reparar defectos superficiales del esmalte es uno muy similar al original y que este interactúe con los mecanismos naturales de remineralización. Este no arregla daños extensos por lo que se requiere de una ayuda externa para rellenar defectos grandes con un material que active la remineralización salivar que sea eficiente pero de menor alcance. Para esto se emplearon cerámicas compuestas principalmente fosfocálcicas. La adhesión efectiva de la reparación puede depender de la cantidad de fluidos acuosos existentes en la porosidad del esmalte pues aparentemente permiten la nucleación y crecimiento de nuevos minerales para asegurar adhesión y estabilidad. La cantidad de fluidos está gobernada por la presión osmótica. En este estudio se evaluó la influencia que tienen dos valores de presión osmótica de la saliva isotónica y hipotónica y dos composiciones de agente remineralizante modificado: condicionador y agente remineralizante en composiciones de 90%/10% (A) y 50%/50%(B) respectivamente, sobre el llenado de grietas artificiales por perfilometría, estereomicroscopio y microscopía confocal láser. Se trabajó con un diseño factorial 22 y tratamiento estadístico: modelo logístico. Solamente la composición de la sustancia remineralizante tuvo efecto significativo en la eficiencia para reparar defectos. La composición tiene un efecto reparador sobre los defectos del esmalte dental en sus dos composiciones, no obstante, la composición 50%/50% presenta niveles más altos de reparación y forma depósitos que al estereomicroscopio se observan más compactos (AU)

Vancomycin loaded gelatin/β-TCP composite porous scaffolds for the treatment of infected tibial bone defect in rabbit / 中华骨科杂志

Objective To confirm the vancomycin loaded gelatin/β-TCP composite porous scaffolds could be used as sustained-release system,and investigate its efficiency of eliminating infections and repairing bone defects for the treatment of infected bone defects in rabbit.Methods The biodegradable gelatin sponge containing different contents (0,10％,30％,50％) of β-tricalcium phosphate ceramic (β-TCP) was prepared for the controlled-release of vancomycin and labeled with G-0 TCP,G-10 TCP,G-30 TCP and G-50 TCP respectively.Examinations of scanning electron microscopy,porosity analyses and mechanical test were performed.The K-B method was used to investigate the controlled release of vancomycin.Chronic Methicillin-resistant Staphylococcus aureus osteomyelitis models of rabbit were established.After thorough debridement,the infected bone defects were treated in four different groups:blank control group,G-0 TCP group,G-10 TCP group,and G-30 TCP group.At 4 and 8 weeks after implantation,X-ray and histological examinations were carried out to investigate the efficiency of eliminating infections and repairing bone defects.Results The prepared gelatin/β-TCP scaffold exhibited a homogeneously interconnected-3-D porous structure.And the β-TCP granules were localized evenly on the walls of the composite scaffold.There were no significant differences in the pore size of different scaffolds.However,the β-TCP granules can improve the interconnection.The porosity exhibited an obvious increase in G-10 TCP and G-30 TCP composite scaffolds compared with G-0 TCP scaffold.In contrast,too high content of β-TCP granules decreased the porosity.And the porosity exhibited an obvious reduction in the G-50 TCP composite scaffold.The compressive modulus of the vancomycin loaded scaffolds increased with the increase of the β-TCP amount.The scaffold G-0 TCP exhibited the longest duration of vancomycin release and the duration reached 8 weeks.With the increased content of β-TCP granules,the release duration shortened obviously.Compared with the G-50 TCP composite scaffold,the G-10 TCP and G-30 TCP composite scaffolds revealed a better controlled release of the drugs,and the total amount of the drugs was released within 7 weeks.However,the total amount of vancomycin released from the G-50 TCP composite scaffold lasted for 3 weeks.In the treatment of chronic MRSA osteomyelitis of rabbits,the G-30 TCP composite scaffold showed a better performance in the eliminating infections and bone defects repair.At 8 weeks after implantation,signs of osteomyelitis,including osteolysis,development of periosteal reactions,and sequestral bone formation were observed in the animals of blank control group.Signs of infection were absent in other treatment group.In the group treated with G-30 TCP composite scaffold,the bonedefects were repaired completely at 8 weeks after implantation.However,in the groups treated with G-0 TCP and G-10 TCP composite scaffold,the bone defects were not repaired.Conclusion The composite scaffolds could achieve local therapeutic drug levels over an extended duration.And the gelatin with 30％ β-TCP granules composite scaffold had optimal porosity,interconnection,mechanical properties and controlled release performances.It exhibited good performances in infection control and bone defect repair in the chronic MRSA osteomyelitis model.