Trends in
Biomaterials & Artificial Organs
A biannual journal published by the 
Society for Biomaterials and Artificial Organs India
ISSN 0971-1198
Volume 20, Number 1, July 2006

Full text can be accessed by clicking on the pdf link.

p 1

Preface pdf

The National Conference on Ceramics for Medical Applications (CMA 2005) held during September 15 -16, 2006, was a unique conference conceived and organized by the Chennai chapters of the Society for Biomaterials and Artificial Organs (SBAOI), and Indian Ceramic Society (InCerS) along with the Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras (IITM) for the first time in India. The CMA 2005 provided front-line researchers, manufacturers, dentists and surgeons involved in bioceramics a platform to share their latest findings and accomplishments and have stimulating discussions as well as enjoyable and educating interactions.

More than 30 abstracts were received for the CMA 2005 from all parts of the country. The overwhelming response was an indication of the growth of research activity in bioceramics in India. Keynote lectures by leading specialists were also arranged to review the current status in the synthesis, processing, characterization and applications of ceramic materials in medicine. Their enthusiastic participation and contributions is highly appreciated by the organizers. All the papers were presented in five oral sessions on biological ceramics, ceramics/composites for dental applications, ceramics/ surfaces in delivery system, biomimetic ceramics/coatings, and novel biomaterials and their synthesis. Three awards for best presentation, technical content and clinical applications were given to the participants. This proceeding contains twelve papers presented at CMA 2005.

I would like to place on record my appreciations to Dr.C.P. Sharma, editor and founder of SBAOI for the offer to publish the proceedings of CMA 2005 as a special issue and to Prof.S.K. Seshadri, Prof. F.D. Gananam and Dr. M. Balasubramanian, co-coordinators, CMA 2005, for their interest and commitment in organizing CMA 2005 as a successful and memorable event. The financial support received from DST, DRDO, DBT and CSIR in organizing the CMA 2005 is gratefully acknowledged. Special thanks are due to Prof.A. Parameswaren, Mr. H. Vijayakumar, and our research scholars and postgraduate students for their help in organizing this conference; and to Ms. Sunita Prem Victor, A.Siddharthan and Dr. Willi Paul for their help in bringing out this proceeding.

T.S. Sampath Kumar 
Guest Editor

p 3-6 pdf

Biomimetically Modified Poly (2-Hydroxy Ethyl Methacrylate-Co-Methyl Methacrylate) Microspheres For Bone Augmentation

G.S. Sailaja, T.V. Kumary and H.K. Varma

Poly(methyl methacrylate), PMMA microspheres are widely used for many orthopaedic and dental infrabony defect filling applications with or without drug loading. However PMMA microspheres are biologically inert and unable to take part actively in bone bonding or regeneration. In the present study a copolymer of methyl methacrylate, poly(2-hydroxy ethyl methacrylate-co-methyl methacrylate) microspheres of 50-250 m, was prepared by suspension polymerization and crosslinked with ethylene glycol di methacrylate (EGDMA). The microspheres were biomimetically modified by phosphorylation using a phosphorylating medium containing phosphoric acid and urea.  The phosphorylated microspheres on immersion in simulated body fluid (SBF), with ionic concentration nearly equal to human blood plasma, induced nucleation of calcium phosphate over the microspheres.  The SEM analysis shows that primary coating was complete within 3 days and the Ca/P ratio of the coating increased with increase in immersion time near to that of hydroxyapatite as observed by EDS analysis. The in vitro cell adhesion behaviour of HOS cells on the polymer substrate was performed by seeding the cells on the polymer substrate for one week.  The cells adhered and covered the substrate by forming a network, keeping their typical morphology.  The phosphorylated microspheres, due to their unique ability to induce in vitro mineralization of bone-like apatite and cell adhesion behaviour could be a potential candidate for bone augmentation.

p 7-11 pdf

Ceramics in Dental Applications

FULL TEXT  Copyright © 2006 Society for Biomaterials and Artificial Organs (India).

p 12-15 pdf

Effect Of Magnetic Field On Biomimetic Coating Of Hydroxyapatite On Titanium

Hydroxyapatite (HA) coating for orthopedic and dental implants does accelerates the bone apposition period. A simple and well adherent coating is possible using biomimetic process, which mimic natural process of HA precipitation in body fluid. Efforts were made to accelerate the coating process duration by increasing the concentration of ions of simulated body fluids. Magnetic therapy has been proven to accelerate the recuperation of patients from fracture and orthopedic ailments. The concept has been applied to biomimetic coating and studied the influence of magnetic field on coating characteristics. Commercially pure titanium of 200 microns thick samples of dimensions 10 x 20 was surface treated by sodium hydroxide treatment (10M NaOH aqueous solution at 80 ^oC for 24 hrs). The samples where immersed in 5 X SBF solution for two weeks. Normal HA coating were compared with the HA coating under permanent magnetic field. The X-ray diffraction (XRD) and Fourier transformed infrared spectroscopy has characterized HA. Scanning electron microscopy (SEM) has shown better dense and finer coating in case of HA coating under magnetic field than normal HA coating.

p 16-19 pdf

Orthodontic tooth movement is carried out, by engaging successively increasing sizes of archwires in brackets, which are bonded to the teeth. Traditionally, brackets as well as archwires were manufactured with Stainless steel or Chrome-Cobalt alloy. Titanium and its alloys have also found their application in this field. With the steady increase in the number of adults undergoing orthodontic treatment, there has been a corresponding increase in demand for more esthetic orthodontic appliances. Ceramics and polycarbonates have been used to produce tooth colored brackets, and research is under way to produce a suitable archwire material, which will combine esthetics with the required mechanical properties. Fiber-reinforced polymer composites are currently being developed for use as orthodontic archwire materials. By adjusting the ceramic/polymer proportions, these wires can be manufactured in a wide range of clinically relevant levels of elastic stiffness, allowing practitioners to use variable-modulus orthodontic techniques without having to change arch wire materials as treatment progresses. Allergic reactions to nickel, which are a debatable concern for many metallic alloys, are also averted with composite materials. With further developments, in the near future, fiber reinforced composite materials are expected to replace metals as the material of choice for orthodontic arch wires.

p 20-23 pdf

Development Of Hydroxyapatite From Natural Fish Bone  Through Heat Treatment

The objective of the present study is to develop hydroxyapatite powder from fishbone through heat treatment method. Fourier transform–infrared spectroscopy (FT-IR) and x-ray diffraction (XRD) techniques were employed to investigate the proof of formation of HAP phase. Presence of characteristic peaks for hydroxyl and phosphate groups were identified by FT-IR studies. XRD analysis reveals the formation phase pure HAP at 900 °C. Electrochemical study involving cyclic polarization experiment was carried out to assess the corrosion resistance behaviour of HAP coated 316L SS in Ringer’s solution. The results have indicated the efficiency of fishbone-originated HAP coatings on 316L SS surface.

p 24-30 pdf

A Study Of In Vitro Drug Release From Zirconia Ceramics

M.Srinivas and G.Buvaneswari

In the field of biomedical applications, Zirconia is an important biomaterial due to its excellent biocompatibility and high mechanical strength. Block forms of such bio inert ceramics can be used as defect bone filler. Designing such implants associated with therapeutic agents like antibiotics, anti-inflammatory etc. exhibiting targeted drug delivery with controlled release profile is a challenge. In the present work, an in vitro drug release of two drug loaded forms (punched pellet and alginate beads) of the zirconia and yttria stabilized zirconia is studied. The ceramics are synthesized by combustion method. The model drugs selected are the antibacterial drug, ciprofloxacin hydrochloride (CFH) and anti-inflammatory drug, diclofenac sodium (DFS).

p 31-34 pdf

Effect Of pH On The Corrosion Behaviour Of Ti-6al-4valloy For Dental Implant Application In Fluoride Media

M. Karthega, S.Tamilselvi And N.Rajendran

In the last few decades, titanium and its alloys have been developed in different areas of dentistry. The chemical properties of the oxide layer formed on the surface of titanium play an important role in the biocompatibility of the titanium implants and surrounding tissues. Generally, fluoride containing preparations have high fluoride concentration and pH range between 7.2 and 3.2. Since, fluorides are inimical to all reactive metals such as titanium especially in acidic medium, leads to corrosion due to the destruction of their passivity and loss of mechanical properties. The presence of fluoride ions in the electrolytic environments brings with it aggressiveness in the attack on titanium. This is due to the formation of complex titanium fluoride molecule, which is very stable and soluble in the electrolytic solution. Hence, the aim of the present work is to study the effect of pH 3.5, 5.0 and 7.0 on Ti-6Al-4V in artificial saliva solution containing 1% NaF (sodium fluoride). Electrochemical studies such as open-circuit potential (OCP) measurements, Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) were carried out in artificial saliva medium.

p 35-39 pdf

Scaffolds for Bone Tissue Restoration From Biological Apatite

R. Murugan, T. S. Sampath Kumar and S. Ramakrishna

A great deal of effort has been exerted to design scaffolds for bone tissue restoration from naturally-derived biomaterials that mimic the composition and structure of natural bone.  This article reports a simple method for processing biological apatite (BAp) from bovine bone.  Chemical and low temperature heat treatments were employed for the processing of BAp scaffold.  Phase composition, microstructure, and compressive strength were examined by various analytical methods.  The results indicated that the phase composition and crystalline structure of BAp correspond to the hydroxyapatite (HAp) phase.  The SEM observation showed that the BAp possesses porous morphology and the pores are in the range of micrometers to nanometers in diameter.  Despite the porous structure, the scaffold possesses adequate mechanical strength required for low-weight bearing orthopedic applications.  The overall experimental results therefore suggest that the BAp may be used as scaffolds for bone tissue restoration.

p 40-43 pdf

Dental Ceramics And Ormocer Technology- Navigating The Future!

A. Sivakumar and  Ashima Valiathan

The use of ceramics in dentistry is a multi-billion dollar industry, involving many different proprietary materials. Current applications of ceramics in dentistry include fillings, crowns, veneers, implants and dental brackets. Dental pins are devices which are inserted into the mandible and are used to hold prosthetic teeth in place.  They are usually made from bioactive materials such as low silica glass or hydroxyl apatite. They are used because of their ability to bond to biological tissues permanently. Composites such as ceramic filled polymers and short fiber reinforcements are also being used. Ormocer is one such material. Ormocer materials contain inorganic-organic copolymers in addition to the inorganic silanated filler particles. It is synthesized through a solution and gelation processes (sol-gel process) from multifunctional urethane and thioether(meth)acrylate alkoxysilanes. Ormocers are described as 3-dimensionally cross-linked copolymers.   Ormocer was formulated in an attempt to overcome the problems created by the polymerization shrinkage of conventional composites because the coefficient of thermal expansion is very similar to natural tooth structure.Ceramics in dentistry will be explored and challenges facing the ceramics community will be emphasized. The key words for dentistry may soon be "fast" and "ceramic. ... And that's where ceramics come in.

p 44-48 pdf

Synthesis and Doxycycline Release Profiles from CDHA Microspheres

Sunita Prem Victor and T S Sampath Kumar

Doxycyclin is a broad-spectrum antibiotic, utilized in the treatment of juvenile periodontitis.. Bone minerals are essentially calcium deficient hydroxyapatite (CDHA), which is compositionally similar to tricalcium phosphate (TCP) and structurally similar to stoichiometric hydroxyapatite (HA). The CDHA is more soluble and more efficient in inducing bone like apatite than HA. The CDHA powder of Ca/P ratio 1.61 was prepared by microwave processing The CDHA microspheres of desired morphology were formed by liquid immiscibility effect using   CDHA/gelatin suspension and oil as liquids. The phase analysis and morphology of the CDHA microspheres were characterized by X-ray powder diffraction (XRD) method,surface area measurements (BET) and scanning electron microscopy  (SEM) respectively. The release profiles were studied by UV spectroscopy at a pH of 7.4. All the microspheres exhibit similar release profiles with an initial gradual increase reaching a maximum value and then nearly a constant release profile as indicated below. However, the amount of   drug release was found to vary with the initial gelatin concentration used for the microsphere preparation. .An optimium release of 80% has been observed.

p 49-52 pdf

Electrochemical Studies On The Stability And Corrosion Resistance Of Ti-5al-2nb-1ta Alloy For Biomedical Applications

S.Tamilselvi And N.Rajendran

Titanium and titanium-based alloys are employed widely in biomedical and dental applications. This is due to the stability and corrosion resistance exhibited by titanium, which is turn is due to the spontaneous formation of a passive titanium dioxide film, typically a few nm thick, which protects the metal from further oxidation. Electrochemical techniques viz., potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) measurements were carried out to investigate the corrosion behavior of titanium and Ti-5Al-2Nb-1Ta alloy in simulated body fluid (SBF) solution. All the measurements were made in the simulated body fluid solution at different duration. Electrochemical impedance spectroscopic results were compared with those obtained by potentiodynamic polarization techniques. Impedance spectra were represented in both complex impedance diagram (Nyquist plot) and Bode plots. The impedance spectra were fitted using a non-linear least square (NLLS) fitting procedure. Double layer capacitance decreases with increase of charge transfer resistance of the titanium alloys studied.

p 53-58 pdf

Versatility Of Ribbond In Contemporary Dental Practice

M.Ganesh and Shobha Tandon

Provision of innovative treatment solutions to various problems has always been the motto of medical scientific brains. Dentistry is no exception to this endeavor. The acceptance of advances in material science has really helped this cause. Ribbond is one such material, which has occupied an important place in the dentist’s repertoire. It is bondable fibre reinforced material, made from the same ultra-high molecular weight polyethylene and ceramic fibers used to make bulletproof vests. The key to Ribbond's success is its patented leno weave. Designed with a lock-stitch feature, it effectively transfers forces throughout the weave without stress transfer back into the resin, providing excellent manageability characteristics. Having virtually no memory, Ribbond adapts to the contours of the teeth and dental arch. It is translucent, practically colorless and disappears within the composite or acrylic without show-through offering excellent esthetics. Ribbond's fibers are the standard in biocompatibility. The same material is also used in the construction of artificial hip and knee joints. By virtue of such wide spectrum of intended properties, it enjoys varied applications in day to day dentistry like: endodontic posts,periodontal splints, aesthetic space maintainers ,bondable briges and single bridges and orthodontic retainers. This paper is an attempt to showcase the versatility and applicability of this wonderful material in day-to-day dental practice.

Articles submitted to the Editor and accepted (from pages 59-100)

p 59-67 pdf

Preparation Of Transparent Starch Based Hydrogel Membrane With Potential Application As Wound Dressing

Kunal Pal, A.K. Banthia and D.K. Majumdar

In the process of wound repair, a biological environment, numerous cellular processes are interlinked. Modern dressings increase the wound-healing rate rather than just to cover it.  Hydrogel dressing can protect injured skin and keep it appropriately moist to speed the healing process. The design and development of novel membrane of hydrogels prepared by crosslinking of polyvinyl alcohol with heat-treated corn-starch suspension was attempted. The membrane was characterized by FTIR spectroscopy and XRD. The mechanical property of the hydrogel membrane was characterized by tensile tests. FTIR spectra of the membrane indicated the presence of free hydroxyl groups and absence of free aldehydic groups. XRD studies indicated that the crystallinity in the membrane was mainly due to PVA. The membranes had sufficient strength to be used as wound dressing. The diffusion coefficient of gatifloxacin, a fourth generation fluoroquinolone,  was determined through the prepared starch hydrogel membrane using a diaphragm cell technique. At 30 °C, the measured value of the diffusion coefficient for gatifloxacin was approximately 3.24×10⁻⁶ cm²/s. The membrane was found to be biocompatible to L929 fibroblast cells.

p 68-71 pdf

Laser Surface Nitriding of Ti-6Al-4V for Bio-implant Application

Amit Biswas, T. K. Maity, U. K. Chatterjee, I. Manna, Lin Li and J. Dutta Majumdar

The present study aims at enhancing the biocompatibility of Ti-6Al-4V by laser surface nitriding. Laser surface nitriding has been carried out by melting of sand blasted Ti-6Al-4V substrate using a high power continuous wave DIODE laser with nitrogen as shrouding environment (at a pressure of 5 l/min). Following laser treatment, a detailed characterization of the surface has been conducted. Microhardness and biocompatibility have been evaluated. Laser surface nitriding led to formation of dendrites of TiN on the surface. The microhardness is improved to 900-950 VHN (in laser surface nitriding) as compared to 260 VHN of as-received substrate. Biocompatibility behavior showed a better cell viability in laser surface nitrided Ti-6Al-4V sample as compared to as-received one.

p 72-77 pdf

Biophysical Evaluation of Vitreous Humor, Its Constituents and Substitutes

Suri S. and Banerjee R.

Vitreous humor, present in the posterior cavity of eye, often becomes dysfunctional due to liquefaction, physical collapse and opacification resulting in its detachment from the retina and vision loss. Materials in clinical use are associated with many complications and search for an ideal substitute is still ongoing. In this study, detailed characterization of the vitreous, its constituents, silicone oil: the presently used substitute, and gellan gum as a possible substitute, was done on the basis of ultrastructure, viscosity, wettability and gelation. Viscosity of the natural vitreous is very high, greater than 4000 cP at a shear rate of 0.15 sec^-1 and shows shear thinning. Environmental Scanning Electron Micrographs (ESEM) revealed a crosslinked structure. Vitreous gel showed syneresis of 12% at 5000 x g and had a glycerol contact angle of 81.4 ± 0.98. At the original concentrations present in the vitreous, Col (0.05 mg/ml) and HA (0.15 mg/ml) individually have maximum viscosity of 0.743 cp and 19.63 cp respectively. Even at 10-fold higher concentrations, the maximum viscosity of HA and collagen individually is lower than vitreous: 164.1 cP and 11.78 cP respectively. Combination of HA and Col even at 5 fold higher than physiological concentrations has maximum viscosity of only 54.7 cP. Viscosity of 1% gellan was> 5000 cP and it underwent gelation at room and body temperature. Gellan gel did not show syneresis and had a glycerol contact angle of 75.17 ± 1.11. Its light transmission was greater than 95% in visual range and ESEM micrographs showed a crosslinked structure. Silicone oil has maximum viscosity of 2600 cP. Its light transmission is 100% in visible range and its contact angle is 91.3 ± 0.60. The contact angle measurements indicated that Silicone oil is more hydrophobic than natural vitreous, thus it makes poor contact with retina. Moreover it is not physiological and does not form a gel. The results of this study indicate that the natural constituents of vitreous on their own are not good as substitutes and that a desirable vitreous substitute should show a maximum viscosity of ≥ 4000 cp, should undergo gelation, syneresis ≤ 12%, light transmission ≥ 90% over visual range and glycerol contact angle of 80°. Though gellan appears promising, further research is required towards development of an ideal vitreous substitute.

p 78-83 pdf

Applications Of Platelet Rich Plasma For Regenerative Therapy In Periodontics

Anila S. and K. Nandakumar

No abstract available.

p 84-89 pdf

Cell Viability and Growth on Metallic Surfaces: in vitro Studies

A. Gupta, P. Majumdar, J.Amit, A. Rajesh, S.B. Singh and M. Chakraborty

Materials to be used as permanent implants in human body must be biocompatible, corrosion resistant, tissue compatible, vital and elastic, in order to serve for a longer period. Titanium and its alloys have become one of the most attractive classes of biomedical implant materials and are generally preferred to stainless steels and Co-Cr alloys because they are light-weight, have superior biocompatibility and corrosion resistance, good mechanical properties and low elastic modulus. Biocompatibility depends upon different material factors such as substrate mechanical origin, surface structure and chemical composition, as well as, on implant design and other factors. The biocompatibility of implant materials is investigated in animal experiments (in vivo test) and cytocompatibility using cells (in vitro test). Implant loosening in bone fixation using bone cement is an unresolved complication associated with internal fixation in orthopedics. In this regard, titanium and titanium-based alloys are promising biomaterials for development of orthopedic implants suitable for cementless fixation. It is generally accepted that the problem of fixation can be overcome by modifying the implantl bone interface for improved osseointegration. Cell attachment and adherence to a surface is the first step that marks the beginning of the biological process. Cell attachment and spreading on alloy surfaces are thus major parameters in cementless orthopedic implant technology. Though titanium and its alloys are already in wide use as dental and orthopedic implants, the effects of the surface characteristics of these materials, including roughness, on the response of target tissues in vivo are not well understood. It has already been proved that cell attachment and biological bonding of a cell and the viability of an adherent cell is highly influenced by the surface characteristics of a biomaterial, especially its roughness, which can be engineered to improve the biocompatibility of an implant, of a given composition.

p 90-100 pdf

Microstructure Development in Machinable Mica Based Dental Glass Ceramics

Shibayan Roy and Bikramjit Basu

Machinable mica based glass ceramic materials with fluorophlogopite as the main crystalline phase in the system K2O-B2O3-Al2O3-SiO2-MgO-F becomes the candidate material for the CAD-CAM dental restoration purpose. In our study, critical heat treatment experiments on this system in the varying temperature range of 1000°-1 120°C with 40°C temperature interval for 4 hrs constant soaking time were carried out. Additionally experiments at 1000°C for varying soaking time of 4-24 hours with 4 hrs time interval were also carried out. Heating rate remains constant at 6.SoC/min for both the cases. The microstrctural changes are observed using optical microscopy. DT A. SEM-EDS, XRD etc. Furthermore, the microhardness of both these batches are measured using Vickers microhardness tester and correlated with the crystal volume fraction. For temperature variation batches, usual and already reported microstructure of interlocked, randomly oriented mica plates are seen. For time variation batches, an important and new observation is that the crystalline phase has a characteristic 'butterfly' like pattern i.e. mica rods are radiating from a central nucleus on both sides which is not reported yet. The possible mechanism for the development of this unusual microstructure is investigated.