International Journal of Biomaterials The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . 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. Weibull Analysis of Fracture Test Data on Bovine Cortical Bone: Influence of Orientation Mon, 09 Dec 2013 10:41:27 +0000 The fracture toughness, , of a cortical bone has been experimentally determined by several researchers. The variation of values occurs from the variation of specimen orientation, shape, and size during the experiment. The fracture toughness of a cortical bone is governed by the severest flaw and, hence, may be analyzed using Weibull statistics. To the best of the authors’ knowledge, however, no studies of this aspect have been published. The motivation of the study is the evaluation of Weibull parameters at the circumferential-longitudinal (CL) and longitudinal-circumferential (LC) directions. We hypothesized that Weibull parameters vary depending on the bone microstructure. In the present work, a two-parameter Weibull statistical model was applied to calculate the plane-strain fracture toughness of bovine femoral cortical bone obtained using specimens extracted from CL and LC directions of the bone. It was found that the Weibull modulus of fracture toughness was larger for CL specimens compared to LC specimens, but the opposite trend was seen for the characteristic fracture toughness. The reason for these trends is the microstructural and extrinsic toughening mechanism differences between CL and LC directions bone. The Weibull parameters found in this study can be applied to develop a damage-mechanics model for bone. Morshed Khandaker and Stephen Ekwaro-Osire Copyright © 2013 Morshed Khandaker and Stephen Ekwaro-Osire. All rights reserved. Isolation and Screening of Polyhydroxyalkanoates Producing Bacteria from Pulp, Paper, and Cardboard Industry Wastes Tue, 29 Oct 2013 11:04:53 +0000 Background. Polyhydroxyalkanoates (PHAs) are storage materials that accumulate by various bacteria as energy and carbon reserve materials. They are biodegradable, environmentally friendly, and also biocompatible bioplastics. Unlike petrochemical-based plastics that take several decades to fully degrade, PHAs can be completely degraded within a year by variety of microorganisms into CO2 and water. In the present study, we aim to utilize pulp, paper, and cardboard industry sludge and waste water for the isolation and screening of polyhydroxyalkanoates (PHAs) accumulating bacteria and production of cost-effective PHB using cardboard industry waste water. Results. A total of 42 isolates showed black-blue coloration when stained with Sudan black B, a preliminary screening agent for lipophilic compounds, and a total of 15 isolates showed positive result with Nile blue A staining, a more specific dye for PHA granules. The isolates NAP11 and NAC1 showed maximum PHA production 79.27% and 77.63% with polymer concentration of 5.236 g/L and 4.042 g/L with cardboard industry waste water. Both of the selected isolates, NAP11 and NAC1, were classified up to genus level by studying their morphological and biochemical characteristics and were found to be Enterococcus sp., Brevundimonas sp. and, respectively. Conclusion. The isolates Enterococcus sp. NAP11 and Brevundimonas sp. NAC1 can be considered as good candidates for industrial production of PHB from cardboard industry waste water. We are reporting for the first time the use of cardboard industry waste water as a cultivation medium for the PHB production. Anish Kumari Bhuwal, Gulab Singh, Neeraj Kumar Aggarwal, Varsha Goyal, and Anita Yadav Copyright © 2013 Anish Kumari Bhuwal et al. All rights reserved. Temperature-Responsive Gelation of Type I Collagen Solutions Involving Fibril Formation and Genipin Crosslinking as a Potential Injectable Hydrogel Sat, 05 Oct 2013 11:16:15 +0000 We investigated the temperature-responsive gelation of collagen/genipin solutions using pepsin-solubilized collagen (PSC) and acid-solubilized collagen (ASC) as substrates. Gelation occurred in the PSC/genipin solutions at genipin concentrations 0–2 mM under moderate change in temperature from 25 to 37°C. The PSC/genipin solutions exhibited fluidity at room temperature for at least 30 min, whereas the ASC/genipin solutions rapidly reached gel points. In specific cases PSC would be preferred over ASC as an injectable gel system. The temperature-responsive gelation of PSC/genipin solutions was due to temperature responses to genipin crosslinking and collagen fibril formation. The elastic modulus of the 0.5% PSC/genipin gel system could be adjusted in a range of 2.5 to 50 kPa by the PSC and genipin concentrations, suggesting that a PSC/genipin solution is a potential injectable gel system for drug and cell carriers, with mechanical properties matching those of living tissues. Shunji Yunoki, Yoshimi Ohyabu, and Hirosuke Hatayama Copyright © 2013 Shunji Yunoki et al. All rights reserved. Development of Chitosan Nanoparticles as a Stable Drug Delivery System for Protein/siRNA Mon, 30 Sep 2013 13:50:31 +0000 Chitosan nanoparticles (CS NPs) exhibit good physicochemical properties as drug delivery systems. The aim of this study is to determine the modulation of preparative parameters on the physical characteristics and colloidal stability of CS NPs. CS NPs were fabricated by ionic interaction with dextran sulphate (DS) prior to determination of their storage stability. The smallest CS NPs of  nm with a surface charge of  mV were produced when CS and DS were mixed at pH 4 and with a DS : CS mass ratio of 0.5 : 1. An entrapment efficiency of 98% was achieved when BSA/siRNA was loaded into the nanoparticles. The results also showed that particle size and surface charge of CS NPs were slightly changed up to 2 weeks when stored at 4°C. Greater particle size and surface charge were obtained with increasing the concentration of DS. In conclusion, NPs were sufficiently stable when kept at 4°C and able to carry and protect protein. Haliza Katas, Maria Abdul Ghafoor Raja, and Kai Leong Lam Copyright © 2013 Haliza Katas et al. All rights reserved. Bone Response to Surface-Modified Titanium Implants: Studies on the Early Tissue Response to Implants with Different Surface Characteristics Mon, 23 Sep 2013 09:09:42 +0000 In a series of experimental studies, the bone formation around systematically modified titanium implants is analyzed. In the present study, three different surface modifications were prepared and evaluated. Glow-discharge cleaning and oxidizing resulted in a highly stoichiometric TiO2 surface, while a glow-discharge treatment in nitrogen gas resulted in implants with essentially a surface of titanium nitride, covered with a very thin titanium oxide. Finally, hydrogen peroxide treatment of implants resulted in an almost stoichiometric TiO2, rich in hydroxyl groups on the surface. Machined commercially pure titanium implants served as controls. Scanning Auger Electron Spectroscopy, Scanning Electron Microscopy, and Atomic Force Microscopy revealed no significant differences in oxide thickness or surface roughness parameters, but differences in the surface chemical composition and apparent topography were observed. After surface preparation, the implants were inserted in cortical bone of rabbits and evaluated after 1, 3, and 6 weeks. Light microscopic evaluation of the tissue response showed that all implants were in contact with bone and had a large proportion of newly formed bone within the threads after 6 weeks. There were no morphological differences between the four groups. Our study shows that a high degree of bone contact and bone formation can be achieved with titanium implants of different surface composition and topography. C. Larsson Wexell, P. Thomsen, B.-O. Aronsson, P. Tengvall, M. Rodahl, J. Lausmaa, B. Kasemo, and L. E. Ericson Copyright © 2013 C. Larsson Wexell et al. All rights reserved. Systemic siRNA Delivery via Peptide-Tagged Polymeric Nanoparticles, Targeting PLK1 Gene in a Mouse Xenograft Model of Colorectal Cancer Sun, 15 Sep 2013 15:08:35 +0000 Polymeric nanoparticles were developed from a series of chemical reactions using chitosan, polyethylene glycol, and a cell-targeting peptide (CP15). The nanoparticles were complexed with PLK1-siRNA. The optimal siRNA loading was achieved at an N : P ratio of 129.2 yielding a nanoparticle size of >200 nm. These nanoparticles were delivered intraperitoneally and tested for efficient delivery, cytotoxicity, and biodistribution in a mouse xenograft model of colorectal cancer. Both unmodified and modified chitosan nanoparticles showed enhanced accumulation at the tumor site. However, the modified chitosan nanoparticles showed considerably, less distribution in other organs. The relative gene expression as evaluated showed efficient delivery of PLK1-siRNA (0.5 mg/kg) with % knockdown () of PLK1 gene. The in vivo data reveals no systemic toxicity in the animals, when tested for systemic inflammation and liver toxicity. These results indicate a potential of using peptide-tagged nanoparticles for systemic delivery of siRNA at the targeted tumor site. Meenakshi Malhotra, Catherine Tomaro-Duchesneau, Shyamali Saha, and Satya Prakash Copyright © 2013 Meenakshi Malhotra et al. All rights reserved. The Use of Porous Scaffold as a Tumor Model Wed, 11 Sep 2013 10:56:20 +0000 Background. Human cancer is a three-dimensional (3D) structure consisting of neighboring cells, extracellular matrix, and blood vessels. It is therefore critical to mimic the cancer cells and their surrounding environment during in vitro study. Our aim was to establish a 3D cancer model using a synthetic composite scaffold. Methods. High-density low-volume seeding was used to promote attachment of a non-small-cell lung cancer cell line (NCI-H460) to scaffolds. Growth patterns in 3D culture were compared with those of monolayers. Immunohistochemistry was conducted to compare the expression of Ki67, CD44, and carbonic anhydrase IX. Results. NCI-H460 readily attached to the scaffold without surface pretreatment at a rate of 35% from a load of 1.5 × 106 cells. Most cells grew vertically to form clumps along the surface of the scaffold, and cell morphology resembled tissue origin; 2D cultures exhibited characteristics of adherent epithelial cancer cell lines. Expression patterns of Ki67, CD44, and CA IX varied markedly between 3D and monolayer cultures. Conclusions. The behavior of cancer cells in our 3D model is similar to tumor growth in vivo. This model will provide the basis for future study using 3D cancer culture. Mei Zhang, Philip Boughton, Barbara Rose, C. Soon Lee, and Angela M. Hong Copyright © 2013 Mei Zhang et al. All rights reserved. Retracted: Free Radical Production in Immune Cell Systems Induced by Ti, Ti6Al4V and SS Assessed by Chemiluminescence Probe Pholasin Assay Mon, 09 Sep 2013 08:21:09 +0000 International Journal of Biomaterials Copyright © 2013 International Journal of Biomaterials. All rights reserved. Evolving Bioprosthetic Tissue Calcification Can Be Quantified Using Serial Multislice CT Scanning Sun, 08 Sep 2013 10:10:59 +0000 Background. We investigated the value of serial multislice CT scanning for in vivo determination of evolving tissue calcification in three separate experimental settings. Materials and Methods. Bioprosthetic valve tissue was implanted in three different conditions: (1) glutaraldehyde-fixed porcine stentless conduits in pulmonary position (); (2) glutaraldehyde-fixed stented pericardial valves in mitral position (); and (3) glutaraldehyde-fixed pericardial tissue as patch in the jugular vein and carotid artery (). Multislice CT scanning was performed at various time intervals. Results. In stentless conduits, the distribution of wall calcification can be reliably quantified with CT. After 20 weeks, the CT-determined mean calcium volume was 1831 ± 581 mm³, with a mean wall calcium content of 89.8 ± 44.4 μg/mg (). In stented pericardial valves implanted in mitral position, reliable determination of tissue mineralization is disturbed by scattering caused by the (continuously moving) alloy of the stent material. Pericardial patches in the neck vessels revealed progressive mineralization, with a significant increase in mean HU and calcium volume at 8 weeks after implantation, rising up to a level of 131.1 ± 39.6 mm³ (mean calcium volume score) and a mean calcium content of 19.1 ± 12.3 μg/mg. Conclusion. The process of bioprosthetic tissue mineralization can be visualized and quantified in vivo using multislice CT scanning. This allows determination of the kinetics of tissue mineralization with intermediate in vivo evaluations. B. Meuris, H. De Praetere, W. Coudyzer, and W. Flameng Copyright © 2013 B. Meuris et al. All rights reserved. Cellular Response to a Novel Fetal Acellular Collagen Matrix: Implications for Tissue Regeneration Mon, 22 Jul 2013 12:30:25 +0000 Introduction. PriMatrix (TEI Biosciences Inc., Boston, MA, USA) is a novel acellular collagen matrix derived from fetal bovine dermis that is designed for use in partial- and full-thickness wounds. This study analyzes the cellular response to PriMatrix in vivo, as well as the ability of this matrix to facilitate normal tissue regeneration. Methods. Five by five mm squares of rehydrated PriMatrix were implanted in a subcutaneous fashion on the dorsum of wild-type mice. Implant site tissue was harvested for histology, immunohistochemistry (IHC), and flow cytometric analyses at multiple time points until day 28. Results. PriMatrix implants were found to go through a biological progression initiated by a transient infiltrate of inflammatory cells, followed by mesenchymal cell recruitment and vascular development. IHC analysis revealed that the majority of the implanted fetal dermal collagen fibers persisted through day 28 but underwent remodeling and cellular repopulation to form tissue with a density and morphology consistent with healthy dermis. Conclusions. PriMatrix implants undergo progressive in vivo remodeling, facilitating the regeneration of histologically normal tissue through a mild inflammatory and progenitor cell response. Regeneration of normal tissue is especially important in a wound environment, and these findings warrant further investigation of PriMatrix in this setting. Robert C. Rennert, Michael Sorkin, Ravi K. Garg, Michael Januszyk, and Geoffrey C. Gurtner Copyright © 2013 Robert C. Rennert et al. All rights reserved. Application of Calcium Phosphate Materials in Dentistry Wed, 26 Jun 2013 14:07:57 +0000 Calcium phosphate materials are similar to bone in composition and in having bioactive and osteoconductive properties. Calcium phosphate materials in different forms, as cements, composites, and coatings, are used in many medical and dental applications. This paper reviews the applications of these materials in dentistry. It presents a brief history, dental applications, and methods for improving their mechanical properties. Notable research is highlighted regarding (1) application of calcium phosphate into various fields in dentistry; (2) improving mechanical properties of calcium phosphate; (3) biomimetic process and functionally graded materials. This paper deals with most common types of the calcium phosphate materials such as hydroxyapatite and tricalcium phosphate which are currently used in dental and medical fields. Jabr S. Al-Sanabani, Ahmed A. Madfa, and Fadhel A. Al-Sanabani Copyright © 2013 Jabr S. Al-Sanabani et al. All rights reserved.