International Journal of Biomaterials The latest articles from Hindawi Publishing Corporation © 2015 , Hindawi Publishing Corporation . All rights reserved. In Vitro Evaluation of Bioactivity of Chemically Deposited Hydroxyapatite on Polyether Ether Ketone Mon, 09 Mar 2015 12:17:16 +0000 Polyether ether ketone (PEEK) is considered the best alternative material for titanium for spinal fusion cage implants due to its low elasticity modulus and radiolucent property. The main problem of PEEK is its bioinert properties. Coating with hydroxyapatite (HA) showed very good improvement in bioactivity of the PEEK implants. However the existing methods for deposition of HA have some disadvantages and damage the PEEK substrate. In our previous study a new method for deposition of HA on PEEK was presented. In this study cell proliferation of mesenchymal stem cell and apatite formation in simulated body fluid (SBF) tests were conducted to probe the effect of this new method in improvement of the bioactivity of PEEK. The mesenchymal stem cell proliferation result showed better cells proliferation on the treated layer in comparison with untreated PEEK. The apatite formation results showed the growth of the HA on the treated PEEK but there was not any sight of the growth of HA on the untreated PEEK even after 2 weeks. The results showed the new method of the HA deposition improved the bioactivity of the treated PEEK in comparison with the bare PEEK. D. Almasi, S. Izman, M. Sadeghi, N. Iqbal, F. Roozbahani, G. Krishnamurithy, T. Kamarul, and M. R. Abdul Kadir Copyright © 2015 D. Almasi et al. All rights reserved. Evaluation of the Clinical Impact of ISO 4049 in Comparison with Miniflexural Test on Mechanical Performances of Resin Based Composite Sat, 28 Feb 2015 09:47:08 +0000 The aim of this study was to evaluate the effect of different specimens dimensions on the mechanical properties of a commercial microfilled resin composite by using a modified ISO 4049 standard protocol, that generally provides specimen dimensions of 25 mm length 2 mm width 2 mm height; these standard dimensions are not clinically realistic considering the teeth diameter and length average. Furthermore, the overlapping irradiations required lead to specimens that are not homogeneous with the presence of some flaws due to packaging steps. For this reason, a miniflexural test was employed in this work both to simulate clinically realistic dimensions and to concentrate fewer defects. The flexural tests were performed at varying span length, in the range between 18.5 mm as stated by the ISO 4049 flexural test (IFT) and 10.5 mm according to the miniflexural test (MFT), at the increasing of layers with a 1 mm buildup multilayering technique. The results evidenced the impact of specimen dimensions on mechanical performances and consequently stability of resin-based composite with the formation of an asymmetrical structure which possesses higher stiffness and strength at increasing layering steps. Luigi Calabrese, Francesca Fabiano, Lucio Maria Bonaccorsi, Valerio Fabiano, and Chiara Borsellino Copyright © 2015 Luigi Calabrese et al. All rights reserved. Fabrication of TiO2 Crystalline Coatings by Combining Ti-6Al-4V Anodic Oxidation and Heat Treatments Sun, 15 Feb 2015 08:37:35 +0000 The bio- and hemocompatibility of titanium alloys are due to the formation of a TiO2 layer. This natural oxide may have fissures which are detrimental to its properties. Anodic oxidation is used to obtain thicker films. By means of this technique, at low voltages oxidation, amorphous and low roughness coatings are obtained, while, above a certain voltage, crystalline and porous coatings are obtained. According to the literature, the crystalline phases of TiO2, anatase, and rutile would present greater biocompatibility than the amorphous phase. On the other hand, for hemocompatible applications, smooth and homogeneous surfaces are required. One way to obtain crystalline and homogeneous coatings is by heat treatments after anodic oxidation. The aim of this study is to evaluate the influence of heat treatments on the thickness, morphology, and crystalline structure of the TiO2 anodic coatings. The characterization was performed by optical and scanning electron microscopy, X-ray diffraction, and X-ray reflectometry. Coatings with different colors of interference were obtained. There were no significant changes in the surface morphology and roughness after heat treatment of 500°C. Heat treated coatings have different proportions of the crystalline phases, depending on the voltage of anodic oxidation and the temperature of the heat treatment. María Laura Vera, Mario Roberto Rosenberger, Carlos Enrique Schvezov, and Alicia Esther Ares Copyright © 2015 María Laura Vera et al. All rights reserved. Histopathological, Histomorphometrical, and Radiographical Evaluation of Injectable Glass-Ceramic-Chitosan Nanocomposite in Bone Reconstruction of Rat Sun, 08 Feb 2015 10:10:31 +0000 Background. Bone defects following tumor resection and osteolysis due to bone lesions, periodontal tissue disorders, and bone reconstruction are challenges that surgeons face. Gass-ceramic-chitosan nanocomposite contains chitosan, a derivative of crustaceans’ exoskeleton. Methods. Thirty-two 6–8-week-old male Wistar rats were chosen. One hole on each right and left tibia was made. The right tibia holes were filled with injectable glass-ceramic-chitosan nanocomposite, and the left tibia holes were left empty. After 7, 14, 28, and 60 days, histopathological, histomorphometrical, and radiographical assessments were performed. Results. Radiographic density on days 7 and 14 was significantly higher in the right tibias than in the left tibias. Trabecular bone thickness, which was higher in the right tibias, increased from day 7 to day 60 in both right and left tibias, although not significantly. Conclusions. Glass-ceramic-chitosan nanocomposite is suggested for use in bone repair in cases of bone loss. More histopathological, histomorphometrical, and radiographical assessments are also recommended. Maryam Seyedmajidi, Seyedmahmood Rabiee, Sina Haghanifar, Seyedkamal Seyedmajidi, Seyed Gholam ali Jorsaraei, Homayoun Alaghehmand, Naghmeh Jamaatlu, and Ali Bijani Copyright © 2015 Maryam Seyedmajidi et al. All rights reserved. Reduction of Silver Ions by Cell Free Extracts of Westiellopsis sp. Sun, 01 Feb 2015 12:54:28 +0000 Biosynthesis of silver nanoparticles using Westiellopsis sp. (A15), a filamentous cyanobacterium belonging to the family Fischerellaceae, has been demonstrated. Aqueous silver ions (Ag+) when exposed to the culture filtrate of Westiellopsis were reduced in the solution, which were characterized by biophysical measures utilizing the UV-Vis spectroscopy, scanning electron microscopy (SEM), and FTIR. The nanoparticles exhibited the maximum absorbance at 420 nm in UV-Vis spectroscopy, while the SEM micrograph revealed that the aggregated nanoparticles vary in size between 20 nm and 5 µm. However, the FTIR analysis provided evidence for presence of proteins in the filtrate to be involved in the reduction of silver ions. P. T. V. Lakshmi, Devi Priyanka, and A. Annamalai Copyright © 2015 P. T. V. Lakshmi et al. All rights reserved. Silver Nanoparticles in Dental Biomaterials Thu, 15 Jan 2015 11:36:45 +0000 Silver has been used in medicine for centuries because of its antimicrobial properties. More recently, silver nanoparticles have been synthesized and incorporated into several biomaterials, since their small size provides great antimicrobial effect, at low filler level. Hence, these nanoparticles have been applied in dentistry, in order to prevent or reduce biofilm formation over dental materials surfaces. This review aims to discuss the current progress in this field, highlighting aspects regarding silver nanoparticles incorporation, such as antimicrobial potential, mechanical properties, cytotoxicity, and long-term effectiveness. We also emphasize the need for more studies to determine the optimal concentration of silver nanoparticle and its release over time. Juliana Mattos Corrêa, Matsuyoshi Mori, Heloísa Lajas Sanches, Adriana Dibo da Cruz, Edgard Poiate Jr., and Isis Andréa Venturini Pola Poiate Copyright © 2015 Juliana Mattos Corrêa et al. All rights reserved. Ciprofloxacin Release Using Natural Rubber Latex Membranes as Carrier Mon, 22 Dec 2014 06:48:15 +0000 Natural rubber latex (NRL) from Hevea brasiliensis is easily manipulated, low cost, is of can stimulate natural angiogenesis and cellular adhesion, is a biocompatible, material and presents high mechanical resistance. Ciprofloxacin (CIP) is a synthetic antibiotic (fluoroquinolone) used in the treatment of infection at external fixation screws sites and remote infections, and this use is increasingly frequent in medical practice. The aim of this study was to develop a novel sustained delivery system for CIP based on NRL membranes and to study its delivery system behavior. CIP was found to be adsorbed on the NRL membrane, according to results of energy dispersive X-ray spectroscopy. Results show that the membrane can release CIP for up to 59.08% in 312 hours and the mechanism is due to super case II (non-Fickian). The kinetics of the drug release could be fitted with double exponential function X-ray diffraction and Fourier transform infrared (FTIR) spectroscopy shows some interaction by hydrogen bound, which influences its mechanical behavior. Heitor Dias Murbach, Guilherme Jaques Ogawa, Felipe Azevedo Borges, Matheus Carlos Romeiro Miranda, Rute Lopes, Natan Roberto de Barros, Alexandre Vinicius Guedes Mazalli, Rosângela Gonçalves da Silva, José Luiz Ferreira Cinman, Bruno de Camargo Drago, and Rondinelli Donizetti Herculano Copyright © 2014 Heitor Dias Murbach et al. All rights reserved. Determination of Oxidative Stress Related Toxicity on Repeated Dermal Exposure of Hydroxyapatite Nanoparticles in Rats Sun, 21 Dec 2014 08:42:24 +0000 Hydroxyapatite nanoparticles (HANPs) have numerous applications, such as substitute for bone grafting, bone fillers, bioceramic coating, and dental fillings. The toxicity of these nanomaterials is of growing concern despite their significant scientific interest and promising potential in many applications. In this study, an in-house synthesized, characterized HANP of size <50 nm was investigated for the dermal toxicity. A paste of HANPs was prepared in water and applied on the dorsal side of the rats for 28 days. At the end of 28 days, blood was subjected to haematological and biochemical analysis. Gross necropsy was conducted and major organs were collected for histopathological observations. Liver from the animals was evaluated for lipid peroxidation, reduced glutathione, and antioxidant enzymes activity. It was observed that none of the animals showed any abnormality during the experimental period. Gross examination of carcasses did not reveal any abnormality in the organs examined. The results also demonstrated that there was no significant fluctuation in the level of antioxidant defense mechanisms, lipid peroxidation, and haematological and biochemical parameters. There was no histopathological lesion observed in any of the organs. Hence, it can be concluded that the synthesized HANPs were nontoxic at cellular level, when exposed dermally to rats. Mohanan Parayanthala Valappil, Syama Santhakumar, and Sabareeswaran Arumugam Copyright © 2014 Mohanan Parayanthala Valappil et al. All rights reserved. Effect of Surface Treated Silicon Dioxide Nanoparticles on Some Mechanical Properties of Maxillofacial Silicone Elastomer Tue, 09 Dec 2014 07:00:07 +0000 Current materials used for maxillofacial prostheses are far from ideal and there is a need for novel improved materials which mimic as close as possible the natural behavior of facial soft tissues. This study aimed to evaluate the effect of adding different concentrations of surface treated silicon dioxide nanoparticles (SiO2) on clinically important mechanical properties of a maxillofacial silicone elastomer. 147 specimens of the silicone elastomer were prepared and divided into seven groups (). One control group was prepared without nanoparticles and six study groups with different concentrations of nanoparticles, from 0.5% to 3% by weight. Specimens were tested for tear strength (ASTM D624), tensile strength (ASTM D412), percent elongation, and shore A hardness. SEM was used to assess the dispersion of nano-SiO2 within the elastomer matrix. Data were analyzed by one-way ANOVA and Scheffe test (). Results revealed significant improvement in all mechanical properties tested, as the concentration of the nanoparticles increased. This was supported by the results of the SEM. Hence, it can be concluded that the incorporation of surface treated SiO2 nanoparticles at concentration of 3% enhanced the overall mechanical properties of A-2186 silicone elastomer. Sara M. Zayed, Ahmad M. Alshimy, and Amal E. Fahmy Copyright © 2014 Sara M. Zayed et al. All rights reserved. Comparative Evaluation of Voids Present in Conventional and Capsulated Glass Ionomer Cements Using Two Different Conditioners: An In Vitro Study Wed, 03 Dec 2014 00:10:05 +0000 This in vitro study evaluated the presence of voids in powder-liquid and capsulated glass ionomer cement. 40 cavities were prepared on root surfaces of maxillary incisors and divided into four groups. Cavities were conditioned with glass ionomer cement liquid (GC Corporation, Tokyo, Japan) in Groups 1 and 3 and with dentin conditioner (GC Corporation, Tokyo, Japan) in Groups 2 and 4. Conventional powder-liquid glass ionomer cement (GC Fuji II, GC Corporation, Tokyo, Japan) was used as a restorative material in Groups 1 and 2. Capsulated glass ionomer cement (GC Fuji II, GC Corporation, Tokyo, Japan) was used in Groups 3 and 4. Samples were sectioned and viewed under stereomicroscope to check for the presence of voids within the cement and at the cement-tooth junction. Data was analyzed using one-way ANOVA and Tukey’s post hoc tests. Group 4 showed statistically significant results () when compared to Groups 1 and 2 for voids within the cement. However, for voids at the margins, the results were statistically insignificant. Mamta Kaushik, Roshni Sharma, Pallavi Reddy, Pallavi Pathak, Pooja Udameshi, and Narmatha Vallakuruchi Jayabal Copyright © 2014 Mamta Kaushik et al. All rights reserved. Direct Metal Laser Sintering Titanium Dental Implants: A Review of the Current Literature Mon, 01 Dec 2014 00:10:06 +0000 Statement of Problem. Direct metal laser sintering (DMLS) is a technology that allows fabrication of complex-shaped objects from powder-based materials, according to a three-dimensional (3D) computer model. With DMLS, it is possible to fabricate titanium dental implants with an inherently porous surface, a key property required of implantation devices. Objective. The aim of this review was to evaluate the evidence for the reliability of DMLS titanium dental implants and their clinical and histologic/histomorphometric outcomes, as well as their mechanical properties. Materials and Methods. Electronic database searches were performed. Inclusion criteria were clinical and radiographic studies, histologic/histomorphometric studies in humans and animals, mechanical evaluations, and in vitro cell culture studies on DMLS titanium implants. Meta-analysis could be performed only for randomized controlled trials (RCTs); to evaluate the methodological quality of observational human studies, the Newcastle-Ottawa scale (NOS) was used. Results. Twenty-seven studies were included in this review. No RCTs were found, and meta-analysis could not be performed. The outcomes of observational human studies were assessed using the NOS: these studies showed medium methodological quality. Conclusions. Several studies have demonstrated the potential for the use of DMLS titanium implants. However, further studies that demonstrate the benefits of DMLS implants over conventional implants are needed. F. Mangano, L. Chambrone, R. van Noort, C. Miller, P. Hatton, and C. Mangano Copyright © 2014 F. Mangano et al. All rights reserved. Analysis of Different Positions of Fiber-Reinforced Composite Retainers versus Multistrand Wire Retainers Using the Finite Element Method Wed, 22 Oct 2014 00:00:00 +0000 Background. The aim of this study was to evaluate root displacement of the lower incisors fixed with FRC in different positions versus FSW retainers using the finite element method. Materials and Methods. 3D finite element models were designed for a mandibular anterior segment: Model 1: flexible spiral wire bonded to the lingual teeth surfaces, Model 2: FRC bonded to the upper third of lingual teeth surfaces, and Model 3: FRC bonded to the middle third. FE analysis was performed for three models and then tooth displacements were evaluated. Results. In contrast to lateral incisors and canines, the FSW retainer caused the central teeth to move more than the teeth bonded with FRC in both loadings. Comparison between Models 2 and 3 (in vertical loading) showed that FRC retainers that bonded at the upper third of lingual teeth surfaces made central and canine teeth move less than FRC retainers bonded at the middle third; however, for lateral teeth it was the opposite. Conclusion. FRC retainers bonded at the upper third of lingual teeth surfaces make central and canine teeth move less than FRC retainers bonded at the middle third in vertical loading; however, for lateral teeth it was the opposite. Arezoo Jahanbin, Mostafa Abtahi, Farzin Heravi, Mohsen Hoseini, and Hooman Shafaee Copyright © 2014 Arezoo Jahanbin et al. All rights reserved. Pore Geometry Optimization of Titanium (Ti6Al4V) Alloy, for Its Application in the Fabrication of Customized Hip Implants Tue, 21 Oct 2014 07:03:46 +0000 The present study investigates the mechanical response of representative volume elements of porous Ti-6Al-4V alloy, to arrive at a desired range of pore geometries that would optimize the reduction in stiffness necessary for biocompatibility with the stress concentration arising around the pore periphery, under physiological loading conditions with respect to orthopedic hip implants. A comparative study of the two is performed with the aid of a newly defined optimizing parameter called pore efficiency that takes into consideration both the stiffness quantity and the stress localization around pores. To perform a detailed analysis of the response of the porous structure over the entire spectrum of loading conditions that a hip implant is subjected to in vivo, the mechanical responses of 3D finite element models of cubic and rectangular parallelepiped geometries, with porosities varying over a range of 10% to 60%, are simulated under representative compressive, flexural as well as combined loading conditions. The results that are obtained are used to suggest a range of pore diameters that lower the effective stiffness and modulus of the implant to around 60% of the stiffness and modulus of dense solid implants while keeping the stress levels within permissible limits. Sandipan Roy, Debojyoti Panda, Niloy Khutia, and Amit Roy Chowdhury Copyright © 2014 Sandipan Roy et al. All rights reserved. A Porous TiAl6V4 Implant Material for Medical Application Thu, 16 Oct 2014 06:23:52 +0000 Increased durability of permanent TiAl6V4 implants still remains a requirement for the patient’s well-being. One way to achieve a better bone-material connection is to enable bone “ingrowth” into the implant. Therefore, a new porous TiAl6V4 material was produced via metal injection moulding (MIM). Specimens with four different porosities were produced using gas-atomised spherical TiAl6V4 with different powder particle diameters, namely, “Small” (<45 μm), “Medium” (45–63 μm), “Mix” (90% 125–180 μm + 10% <45 μm), and “Large” (125–180 μm). Tensile tests, compression tests, and resonant ultrasound spectroscopy (RUS) were used to analyse mechanical properties. These tests revealed an increasing Young’s modulus with decreasing porosity; that is, “Large” and “Mix” exhibit mechanical properties closer to bone than to bulk material. By applying X-ray tomography (3D volume) and optical metallographic methods (2D volume and dimensions) the pores were dissected. The pore analysis of the “Mix” and “Large” samples showed pore volumes between 29% and 34%, respectively, with pore diameters ranging up to 175 μm and even above 200 μm for “Large.” Material cytotoxicity on bone cell lines (SaOs-2 and MG-63) and primary cells (human bone-derived cells, HBDC) was studied by MTT assays and highlighted an increasing viability with higher porosity. Axel Deing, Bérengère Luthringer, Daniel Laipple, Thomas Ebel, and Regine Willumeit Copyright © 2014 Axel Deing et al. All rights reserved. In Vitro Evaluation of the Antimicrobial Efficacy of Four Endodontic Biomaterials against Enterococcus faecalis, Candida albicans, and Staphylococcus aureus Sun, 12 Oct 2014 12:35:04 +0000 Root canal sealers that possess good antimicrobial property can prevent residual and recurrent infection and contribute to successful endodontic therapy. This study evaluated the antimicrobial activity of four endodontic sealers, AH Plus, Tubliseal EWT, EndoRez, and iRoot SP, against three different microorganisms, E. faecalis, C. albicans, and S. aureus, by direct contact test. 10 μL microbial suspensions were allowed to directly contact the four endodontic sealers for 1 hr at 37°C. Subsequently microbial growth was measured spectrophotometrically every 30 min for 18 hours. The microbial suspensions were simultaneously tested to determine the antimicrobial effect of components which are capable of diffusing into the medium. The results revealed that AH Plus and iRootSP had significantly higher antimicrobial activity against E. faecalis. AH Plus and Tubliseal EWT showed significantly higher antimicrobial activity against C. albicans and S. aureus compared to iRoot SP and EndoRez. EndoRez showed the least antimicrobial activity against all the three microorganisms. Inhibition of microbial growth is related to the direct contact of microorganisms with the sealers. In conclusion AH Plus had significantly higher antimicrobial activity against E. faecalis, C. albicans, and S. aureus. Duddi Narendra Nirupama, Mohan Thomas Nainan, Rajendran Ramaswamy, Sethumadhavan Muralidharan, Hulimangala Hosakote Lingareddy Usha, Roshni Sharma, and Soham Gupta Copyright © 2014 Duddi Narendra Nirupama et al. All rights reserved. An Investigation of Biodiesel Production from Wastes of Seafood Restaurants Tue, 07 Oct 2014 07:35:52 +0000 This work illustrates a comparative study on the applicability of the basic heterogeneous calcium oxide catalyst prepared from waste mollusks and crabs shells (MS and CS, resp.) in the transesterification of waste cooking oil collected from seafood restaurants with methanol for production of biodiesel. Response surface methodology RSM based on D-optimal deign of experiments was employed to study the significance and interactive effect of methanol to oil M : O molar ratio, catalyst concentration, reaction time, and mixing rate on biodiesel yield. Second-order quadratic model equations were obtained describing the interrelationships between dependent and independent variables to maximize the response variable (biodiesel yield) and the validity of the predicted models were confirmed. The activity of the produced green catalysts was better than that of chemical CaO and immobilized enzyme Novozym 435. Fuel properties of the produced biodiesel were measured and compared with those of Egyptian petro-diesel and international biodiesel standards. The biodiesel produced using MS-CaO recorded higher quality than that produced using CS-CaO. The overall biodiesel characteristics were acceptable, encouraging application of CaO prepared from waste MS and CS for production of biodiesel as an efficient, environmentally friendly, sustainable, and low cost heterogeneous catalyst. Nour Sh. El-Gendy, A. Hamdy, and Salem S. Abu Amr Copyright © 2014 Nour Sh. El-Gendy et al. All rights reserved. The Evaluation of Various Restoration Techniques on Internal Adaptation of Composites in Class V Cavities Thu, 02 Oct 2014 12:56:58 +0000 Aim. The aim of this study was to evaluate the effect of different restoration techniques on the formation of internal microgaps between materials and dentin in class V restorations. Materials and Methods. Twenty-five extracted human premolars were prepared with standardized class V cavity outlines (3 mm × 2 mm × 2 mm). The cavities were randomly divided into 5 groups of 10 cavities each and restored according to manufacturer’s instructions: Group 1: preheating (55°C) conventional composite (Filtek Z250), Group 2: flowable composite (Filtek Flow), Group 3: Filtek Flow + Filtek Z250 light-cured separately, Group 4: Filtek Flow + Filtek Z250 light-cured simultaneously, and Group 5 (control): Filtek Z250 at room temperature (23°C). The specimens were then thermocycled and cross-sectioned through the center of the restoration. Subsequently, impressions were taken, and epoxy resin replicas were made. The internal adaptation of the materials to the axial wall was analyzed under SEM. Results. The preheated Filtek Z250 (Group 1) showed better internal adaptation than the room temperature groups . The combination of Filtek Flow with Filtek Z250 which was light-cured separately (Group 3) exhibited better internal adaptation than control group . Conclusion. Different restoration techniques exhibit different behavior regarding internal adaptation to dentin after photopolymerization. D. Dionysopoulos, C. Papadopoulos, and E. Koliniotou-Koumpia Copyright © 2014 D. Dionysopoulos et al. All rights reserved. Antibacterial Efficacy of Iron-Oxide Nanoparticles against Biofilms on Different Biomaterial Surfaces Tue, 23 Sep 2014 05:27:47 +0000 Biofilm growth on the implant surface is the number one cause of the failure of the implants. Biofilms on implant surfaces are hard to eliminate by antibiotics due to the protection offered by the exopolymeric substances that embed the organisms in a matrix, impenetrable for most antibiotics and immune cells. Application of metals in nanoscale is considered to resolve biofilm formation. Here we studied the effect of iron-oxide nanoparticles over biofilm formation on different biomaterial surfaces and pluronic coated surfaces. Bacterial adhesion for 30 min showed significant reduction in bacterial adhesion on pluronic coated surfaces compared to other surfaces. Subsequently, bacteria were allowed to grow for 24 h in the presence of different concentrations of iron-oxide nanoparticles. A significant reduction in biofilm growth was observed in the presence of the highest concentration of iron-oxide nanoparticles on pluronic coated surfaces compared to other surfaces. Therefore, combination of polymer brush coating and iron-oxide nanoparticles could show a significant reduction in biofilm formation. Monica Thukkaram, Soundarya Sitaram, Sathish kumar Kannaiyan, and Guruprakash Subbiahdoss Copyright © 2014 Monica Thukkaram et al. All rights reserved. Effect of Nanoclay Dispersion on the Properties of a Commercial Glass Ionomer Cement Tue, 26 Aug 2014 00:00:00 +0000 Objective. The reinforcement effect of polymer-grade montmorillonite (PGV and PGN nanoclay) on Fuji-IX glass ionomer cement was investigated. Materials and Method. PGV and PGV nanoclays (2.0 wt%) were dispersed in the liquid portion of Fuji-IX. Fourier-transform infrared (FTIR) spectroscopy and gel permeation chromatography (GPC) were used to quantify acid-base reaction and the liquid portion of GIC. The mechanical properties (CS, DTS, FS, and ) of cements (n = 20) were measured at 1 hour, 1 day, and 1 month. The microstructure was examined by cryo-SEM and TEM. Results. FTIR shows that the setting reaction involves the neutralisation of PAA by the glass powder which was linked with the formation of calcium and aluminium salt-complexes. The experimental GICs (C-V and C-N) exhibited mechanical properties in compliance to ISO standard requirement have higher values than Fuji-IX cement. There was no significant correlation of mechanical properties was found between C-V and C-N. The average Mw of Fuji-IX was 15,700 and the refractive index chromatogram peak area was 33,800. TEM observation confirmed that nanoclays were mostly exfoliated and dispersed in the matrix of GIC. Conclusion. The reinforcement of nanoclays in GICs may potentially produce cements with better mechanical properties without compromising the nature of polyacid neutralisation. Muhammad A. Fareed and Artemis Stamboulis Copyright © 2014 Muhammad A. Fareed and Artemis Stamboulis. All rights reserved. Optimisation and In Vivo Evaluation of Pectin Based Drug Delivery System Containing Curcumin for Colon Wed, 02 Jul 2014 00:00:00 +0000 The higher incidences of side effects of existing drugs have shifted researchers and clinicians to explore the dietary phytoconstituents for its therapeutic potentials. The present study is based on compression coated curcumin tablet for the colon. Curcumin has anti-inflammatory and antioxidant properties. Curcumin presents a bioavailability problem due to poor solubility. An inclusion complex was formed with hydroxypropyl-β-cyclodextrin to enhance the solubility. In this study, the core tablet of curcumin inclusion complex was compressed between the layers of polymer blend of pectin and Eudragit S100. The 32 full factorial design was utilised for optimization of the formulation. The polymer ratio (X1) and coat thickness (X2) presented significant effects on the selected responses, i.e., percent drug release after 4 hours (Y240) and difference in percent drug release between 4th and 6th hour () in presence of pectinase enzyme. The results revealed that higher coat weight (600 mg) and higher level of pectin ratio (70% w/w) protected the curcumin tablet till ascending colon. The in vivo studies by roentgenography method using human volunteers supported these observations. Hence, it can be concluded that the combination of pectin and Eudrgit S100 makes the system biodegradable and pH dependent for targeting the drug to the colon. Kishor Butte, Munira Momin, and Hemant Deshmukh Copyright © 2014 Kishor Butte et al. All rights reserved. Synthesis, Characterization, and Osteoblastic Cell Culture of Poly(L-co-D,L-lactide-co-trimethylene carbonate) Scaffolds Wed, 25 Jun 2014 11:02:09 +0000 Lactide-based polymers have been widely investigated as materials for tissue engineering. However, characteristics such as low flexibility and elongation tend to limit particular applications, although these can be enhanced by adding plasticizers such as trimethylene carbonate (TMC) to the polymer chain of the copolymer poly(L-lactide-co-D,L-lactide) (PLDLA). The aim of this work was to synthesize and characterize a terpolymer of L-lactide, D,L-lactide, and TMC. The polymers were synthesized from 30% TMC by bulk polymerization and resulted in an average molar mass >105 g/mol. Thermal investigation of PLDLA-TMC showed a decrease in the glass transition and onset temperatures compared to PLDLA. PLDLA-TMC scaffolds stimulated the proliferation and normal phenotypic manifestations of cultured osteoblasts. These results show that it was possible to produce a terpolymer from L-lactide, D,L-lactide, and TMC. Scaffolds of this terpolymer had important characteristics that could be useful for applications in bone tissue engineering. André Dutra Messias, Kelly Fernanda Martins, Adriana Cristina Motta, and Eliana Aparecida de Rezende Duek Copyright © 2014 André Dutra Messias et al. All rights reserved. Bone Formation with Deproteinized Bovine Bone Mineral or Biphasic Calcium Phosphate in the Presence of Autologous Platelet Lysate: Comparative Investigation in Rabbit Tue, 27 May 2014 08:58:12 +0000 Bone substitutes alone or supplemented with platelet-derived concentrates are widely used to promote bone regeneration but their potency remains controversial. The aim of this study was, therefore, to compare the regenerative potential of preparations containing autologous platelet lysate (APL) and particles of either deproteinized bovine bone mineral (DBBM) or biphasic calcium phosphate (BCP), two bone substitutes with different resorption patterns. Rabbit APL was prepared by freeze-thawing a platelet suspension. Critical-size defects in rabbit femoral condyle were filled with DBBM or DBBM+APL and BCP or BCP+APL. Rabbits were sacrificed after six weeks and newly formed bone and residual implanted material were evaluated using nondemineralized histology and histomorphometry. New bone was observed around particles of all fillers tested. In the defects filled with BCP, the newly formed bone area was greater (70%; ) while the residual material area was lower (60%; ) than that observed in those filled with DBBM. New bone and residual material area of defects filled with either APL+DBBM or APL+BCP were similar to those observed in those filled with the material alone. In summary, osteoconductivity and resorption of BCP were greater than those of DBBM, while APL associated with either DBBM or BCP did not have an additional benefit. Carole Chakar, Nada Naaman, Emmanuel Soffer, Nicolas Cohen, Nada El Osta, Hervé Petite, and Fani Anagnostou Copyright © 2014 Carole Chakar et al. All rights reserved. Increasing Thermal Stability of Gelatin by UV-Induced Cross-Linking with Glucose Wed, 21 May 2014 09:05:32 +0000 The effects of ultraviolet (254 nm) radiation on a hydrated gelatin-glucose matrix were investigated for the development of a physiologically thermostable substrate for potential use in cell scaffold production. Experiments conducted with a differential scanning calorimeter indicate that ultraviolet irradiation of gelatin-glucose hydrogels dramatically increases thermal stability such that no melting is observed at temperatures of at least 90°C. The addition of glucose significantly increases the yield of cross-linked product, suggesting that glucose has a role in cross-link formation. Comparisons of lyophilized samples using scanning electron microscopy show that irradiated materials have visibly different densities. Evan M. Masutani, Christopher K. Kinoshita, Travis T. Tanaka, Andrew K. D. Ellison, and Brandon A. Yoza Copyright © 2014 Evan M. Masutani et al. All rights reserved. In Vitro Evaluation of Some Types of Ferrimagnetic Glass Ceramics Thu, 08 May 2014 00:00:00 +0000 The present study aimed at studying the acceleration of the bioactive layer on the surface of ferrimagnetic glass ceramic with a basic composition 40Fe2O3–15P2O5–20SiO2–5TiO2 through the addition of 20% of different types of metal oxides like MgO or CaO or MnO or CuO or ZnO or CeO2. SEM, EDAX, and ICP were applied to present the results of the study. SEM and EDAX measurements indicated the presence of apatite layer formed on the surface of the prepared glass ceramics after immersion in SBF within 7 to 30 days. The investigation of the results clarified that the addition of CaO or ZnO accelerated the formation of apatite on the surfaces of the samples in the simulated body fluid faster than other metal oxides. Inductive coupled plasma (ICP) analysis shows the evolution of ion extraction by the simulated body fluid solution (SBF) with time in relation to the elemental composition. S. A. M. Abdel-Hameed, M. A. Marzouk, and R. L. Elwan Copyright © 2014 S. A. M. Abdel-Hameed et al. All rights reserved. Preparation of Starch/Gelatin Blend Microparticles by a Water-in-Oil Emulsion Method for Controlled Release Drug Delivery Tue, 29 Apr 2014 08:14:09 +0000 Information on the preparation and properties of starch/gelatin blend microparticles with and without crosslinking for drug delivery is presented. The blend microparticles were prepared by the water-in-oil emulsion solvent diffusion method. Glutaraldehyde and methylene blue were used as the crosslinker and the water-soluble drug model, respectively. The blend microparticles were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and UV-Vis spectroscopy. The functional groups of the starch and gelatin blend matrices were determined from the FTIR spectra. Blend microparticles with a nearly spherical shape and internal porous structure were observed from SEM images. The average particle size of the gelatin microparticles depended on the crosslinker ratio but not on the starch/gelatin blend ratio. The in vitro drug release content significantly decreased as the crosslinker ratio increased and the starch blend ratio decreased. The results demonstrated that the starch/gelatin blend microparticles should be a useful controlled release delivery carrier for water-soluble drugs. Theeraphol Phromsopha and Yodthong Baimark Copyright © 2014 Theeraphol Phromsopha and Yodthong Baimark. All rights reserved. Controlled Release of Granulocyte Colony-Stimulating Factor Enhances Osteoconductive and Biodegradable Properties of Beta-Tricalcium Phosphate in a Rat Calvarial Defect Model Mon, 14 Apr 2014 10:45:48 +0000 Autologous bone grafts remain the gold standard for the treatment of congenital craniofacial disorders; however, there are potential problems including donor site morbidity and limitations to the amount of bone that can be harvested. Recent studies suggest that granulocyte colony-stimulating factor (G-CSF) promotes fracture healing or osteogenesis. The purpose of the present study was to investigate whether topically applied G-CSF can stimulate the osteoconductive properties of beta-tricalcium phosphate (β-TCP) in a rat calvarial defect model. A total of 27 calvarial defects 5 mm in diameter were randomly divided into nine groups, which were treated with various combinations of a β-TCP disc and G-CSF in solution form or controlled release system using gelatin hydrogel. Histologic and histomorphometric analyses were performed at eight weeks postoperatively. The controlled release of low-dose (1 μg and 5 μg) G-CSF significantly enhanced new bone formation when combined with a β-TCP disc. Moreover, administration of 5 μg G-CSF using a controlled release system significantly promoted the biodegradable properties of β-TCP. In conclusion, the controlled release of 5 μg G-CSF significantly enhanced the osteoconductive and biodegradable properties of β-TCP. The combination of G-CSF slow-release and β-TCP is a novel and promising approach for treating pediatric craniofacial bone defects. Tomohiro Minagawa, Yasuhiko Tabata, Akihiko Oyama, Hiroshi Furukawa, Takeshi Yamao, and Yuhei Yamamoto Copyright © 2014 Tomohiro Minagawa et al. All rights reserved. A Novel Qualitative and Quantitative Biofilm Assay Based on 3D Soft Tissue Tue, 18 Feb 2014 15:13:35 +0000 The lack of predictable in vitro methods to analyze antimicrobial activity could play a role in the development of resistance to antibiotics. Current used methods analyze planktonic cells but for the method to be clinically relevant, biofilm in in vivo like conditions ought to be studied. Hence, our group has developed a qualitative and quantitative method with in vivo like 3D tissue for prediction of antimicrobial activity in reality. Devices (wound dressings) were applied on top of Pseudomonas aeruginosa inoculated Muller-Hinton (MH) agar or 3D synthetic soft tissues (SST) and incubated for 24 hours. The antibacterial activity was then analyzed visually and by viable counts. On MH agar two out of three silver containing devices showed zone of inhibitions (ZOI) and on SST, ZOI were detected for all three. Corroborating results were found upon evaluating the bacterial load in SST and shown to be silver concentration dependent. In conclusion, a novel method was developed combining visual rapid screening and quantitative evaluation of the antimicrobial activity in both tissue and devices. It uses tissue allowing biofilm formation thus mimicking reality closely. These conditions are essential in order to predict antimicrobial activity of medical devices in the task to prevent device related infections. Bodil Hakonen, Linnea K. Lönnberg, Eva Larkö, and Kristina Blom Copyright © 2014 Bodil Hakonen et al. All rights reserved. IVIVC from Long Acting Olanzapine Microspheres Wed, 22 Jan 2014 00:00:00 +0000 In this study, four PLGA microsphere formulations of Olanzapine were characterized on the basis of their in vitro behavior at 37°C, using a dialysis based method, with the goal of obtaining an IVIVC. In vivo profiles were determined by deconvolution (Nelson-Wagner method) and using fractional AUC. The in vitro and in vivo release profiles exhibited the same rank order of drug release. Further, in vivo profiles obtained with both approaches were nearly superimposable, suggesting that fractional AUC could be used as an alternative to the Nelson-Wagner method. A comparison of drug release profiles for the four formulations revealed that the in vitro profile lagged slightly behind in vivo release, but the results were not statistically significant (). Using the four formulations that exhibited different release rates, a Level A IVIVC was established using the deconvolution and fractional AUC approaches. A nearly 1 : 1 correlation () between in vitro release and in vivo measurements confirmed the excellent relationship between in vitro drug release and the amount of drug absorbed in vivo. The results of this study suggest that proper selection of an in vitro method will greatly aid in establishing a Level A IVIVC for long acting injectables. Susan D'Souza, Jabar A. Faraj, Stefano Giovagnoli, and Patrick P. DeLuca Copyright © 2014 Susan D'Souza et al. All rights reserved. Blends of Thermoplastic Polyurethane and Polydimethylsiloxane Rubber: Assessment of Biocompatibility and Suture Holding Strength of Membranes Wed, 18 Dec 2013 09:23:10 +0000 In the present investigation, a compatibilized blend of thermoplastic polyurethane (TPU) and polydimethylsiloxane (PDMS) is prepared by using copolymer of ethylene and methyl acrylate (EMA) as a reactive compatibilizer. Detailed in vitro biocompatibility studies were carried out for this compatibilized blend and the material was found noncytotoxic towards L929 mouse fibroblast subcutaneous connective tissue cell line. Microporosity was created on the surface of membranes prepared from the blend material by adopting the crazing mechanism. Cell proliferation and growth studies on the membranes surface showed that the microporous surface favoured ingrowth of the cells compared with a nonmicroporous surface. Suture holding strength studies indicate that the microporous membranes have enough strength to withstand the cutting and tearing forces through the suture hole. This blend material could be evaluated further to find its suitability in various implant applications. Krishna Prasad Rajan, Ahmed Al-Ghamdi, Ramesh Parameswar, and G. B. Nando Copyright © 2013 Krishna Prasad Rajan et al. All rights reserved. Bone Substitutes for Peri-Implant Defects of Postextraction Implants Thu, 12 Dec 2013 11:22:11 +0000 Placement of implants in fresh sockets is an alternative to try to reduce physiological resorption of alveolar ridge after tooth extraction. This surgery can be used to preserve the bone architecture and also accelerate the restorative procedure. However, the diastasis observed between bone and implant may influence osseointegration. So, autogenous bone graft and/or biomaterials have been used to fill this gap. Considering the importance of bone repair for treatment with implants placed immediately after tooth extraction, this study aimed to present a literature review about biomaterials surrounding immediate dental implants. The search included 56 articles published from 1969 to 2012. The results were based on data analysis and discussion. It was observed that implant fixation immediately after extraction is a reliable alternative to reduce the treatment length of prosthetic restoration. In general, the biomaterial should be used to increase bone/implant contact and enhance osseointegration. Pâmela Letícia Santos, Jéssica Lemos Gulinelli, Cristino da Silva Telles, Walter Betoni Júnior, Roberta Okamoto, Vivian Chiacchio Buchignani, and Thallita Pereira Queiroz Copyright © 2013 Pâmela Letícia Santos et al. All rights reserved.