|Articles about Biomaterials|
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| Patent literature as a source of information for research and development: an investigation on calcium phosphate-containing biomaterials, Part I
Wustefeld, M. and K. de Groot (1989), J Biomed Mater Res 23(A1 Suppl): 41-71.
Abstract: The usefulness of patent literature for research and development is mostly unknown. Therefore a specific patent retrieval has been carried out concerning calcium phosphate-containing biomaterials. This research field includes chemical, medical, and engineering problems and is of importance to the development of bioactive materials for bone replacement. The preliminary work includes information on the characteristics and the availability of patent literature as well as about patent classification systems according to which the documents are filed in patent collections. By reading the non-patent literature searching questions can be formulated. The proper patent retrieval starts with the study of secondary literature especially that in Chemical Abstracts, which report on patents since 1907. The structure of Chemical Abstracts, their indexes and sections help to find relevant patents of chemical or chemical engineering contents fast and inspire to read patents of bordering areas. This retrieval from Chemical Abstracts led to 171 patents disclosed 1975-1985 and to 95 patents disclosed in 1986; the latter are listed in a table. The contents of the abstracts inform on the research activity and help to reduce time and effort for a continuation of the retrieval in a patent collections or database.
| Pathogenesis and prevention of biomaterial centered infections
Gottenbos, B., H. J. Busscher, et al. (2002), J Mater Sci Mater Med 13(8): 717-22.
Abstract: One of the major drawbacks in the use of biomedical materials is the occurrence of biomaterials centered infections. After implantation, the host interacts with a biomaterial by forming a conditioning film on its surface and an immune reaction towards the foreign material. When microorganisms can reach the biomaterials surface they can adhere to it. Adhesion of microorganisms to an implant is mediated by their physico-chemical surface properties and the properties of the biomaterials surface itself. Subsequent surface growth of the microorganisms will lead to a mature biofilm and infection, which is difficult to eradicate by antibiotics. The purpose of this review is to give an overview of the mechanisms involved in biomaterials centered infection and the possible methods to prevent these infections.
| Pathological calcification in juvenile dermatomyositis (JDM): microCT and synchrotron x-ray diffraction reveal hydroxyapatite with varied microstructures
Stock, S., K. Ignatiev, et al. (2004), Connect Tissue Res 45(4-5): 248-56.
Abstract: The objective of this study was to begin to relate the microstructure of calcinosis samples to clinical and laboratory characteristics of the juvenile dermatomyositis (JDM) patients. Laboratory x-ray microCT (micro-Computed Tomography) noninvasively mapped microstructure for the first time in JDM calcifications. Synchrotron x-ray diffraction (transmission geometry) identified the mineral phase and crystallite size in the deposits. Samples were obtained from four children who had active JDM longer than 80 months and who were typed for TNFalpha-308 allele polymorphisms. Uniform mineral (giving the appearance of an extruded solid) was observed in one patient, and irregular blocks of differing sizes filled the samples from two other patients. The sample from the fourth patient appeared to combine features of the other two types. These spatial distributions of mineral were quite different from those in a bone reference sample. The only mineral observed in the JDM samples was hydroxyapatite (HAP), and the diffraction peaks of the JDM samples were slightly narrower than those of a trabecular bone reference sample. Diffraction peak widths of the JDM specimens revealed crystallite sizes (approximately 220-240 A) that are comparable to values reported in the literature for bone. Three children were positive for TNFalpha-308 GA polymorphism. The data suggest several possible origins for blocky vs. uniform structure of the JDM calcifications, including differences in duration of untreated inflammation, in TNFalpha-308 polymorphism, and in mechanical constraint at the calcification site. Information from additional samples is required to determine the relative role of each of these factors. Taken together, non-invasive microCT and x-ray diffraction characterization on the same samples offer an informative window into the dystrophic mineralization process in JDM.
| Pathological mineralization of cardiac valves: causes and mechanism
Suvorova, E. I. and P. A. Buffat (2005), J Long Term Eff Med Implants 15(4): 355-68.
Abstract: OBJECTIVE: Mechanism of calcification of cardiac valves was investigated through a comparative characterization of structure, morphology, and size of hydroxyapatite (HAP) crystals formed in mineral deposit on cardiac valves, bone tissue, and crystals synthesized from aqueous solutions under definite conditions. METHODS: All deposits on cardiac valves and bone samples were characterized by scanning electron microscopy (SEM) and energy dispersive X-ray microanalysis (EDS) in a Philips XL30 FEG microscope to evaluate their overall view and structure, to estimate the sizes of particles, and to carry out the chemical analysis. High resolution transmission electron microscopy (HRTEM) and electron micro diffraction was done for precise phase identification of individual crystals and measurements of their sizes. RESULTS: Mineral deposit on cardiac valves contained hydroxyapatite crystals (HAP) crystals with lengths from a few nanometers to a few hundred nanometers. Similar to the HAP precipitation in aqueous solutions, crystals in deposit were randomly oriented relative to each other and without the substrate effect on their orientation. Octacalcium phosphate (OCP) phase was also detected in the form of large (up to a few microns) crystals. The quantity of the OCP crystals was quite low in comparison with the amount of the HAP crystals. HAP crystals in bone samples were no more than 20 nm in length and textured in the HAP  direction along collagen fibers. The HAP crystals from cardiac valves and bones were of uniform thickness comparable with the crystallographic unit cell. CONCLUSIONS: Mass crystallization model and hemodynamics in heart and arteries determine the mechanism of pathological calcification through the mediation of hydroxyapatite nanocrystals perpetually circulating with the bloodstream.
| Patients' choice of dental treatment following examination at a specialty unit for adverse reactions to dental materials
Lygre, G. B., N. R. Gjerdet, et al. (2004), Acta Odontol Scand 62(5): 258-63.
Abstract: The Dental Biomaterials Adverse Reaction Unit in Bergen, Norway, is a national unit for the examination of patients with suspected adverse reactions to dental materials. The aim of this study was to investigate whether patients with suspected adverse reactions to dental materials experienced improvement in health after dental restorations had been replaced, and whether they had acted according to the recommendations of the Unit. A questionnaire was sent to 358 patients who had been examined at the Unit 18 months to 7 years earlier. Of the 207 patients who completed the questionnaire, 85 had had restorative materials replaced with other types of materials. A majority had had amalgam fillings replaced. After replacement, 51 patients reported an improvement in health. Twelve patients reported that they felt worse after replacement. The Unit recommended replacement of materials in 31 patients, of whom 24 followed the recommendation. Among 176 patients who were not given specific recommendations as to replacement of dental materials, 67 had had their restorations replaced, and 40 had started to have them replaced. It appears that the examination at the Dental Biomaterials Adverse Reaction Unit is one of several inputs that influence a person's decision to replace dental materials.
| Patterned assembly of genetically modified viral nanotemplates via nucleic acid hybridization
Yi, H., S. Nisar, et al. (2005), Nano Lett 5(10): 1931-6.
Abstract: The patterning of nanoparticles represents a significant obstacle in the assembly of nanoscale materials and devices. In this report, cysteine residues were genetically engineered onto the virion surface of tobacco mosaic virus (TMV), providing attachment sites for fluorescent markers. To pattern these viruses, labeled virions were partially disassembled to expose 5' end RNA sequences and hybridized to virus-specific probe DNA linked to electrodeposited chitosan. Electron microscopy and RNAase treatments confirmed the patterned assembly of the virus templates onto the chitosan surface. These findings demonstrate that TMV nanotemplates can be dimensionally assembled via nucleic acid hybridization.
| Patterns of histopathological change determined by the point counting method and its application for the hazard assessment of respirable dust
Ogami, A., Y. Morimoto, et al. (2004), Inhal Toxicol 16(11-12): 793-800.
Abstract: We evaluate the morphometric point counting method (PCM) for qualitatively analyzing pulmonary inflammation and collagen deposits (i.e., fibrosis) in the assessment of the biological hazards of inhaled respirable particles at a realistic dose comparable to that of exposure in the work environment. Rats were exposed by intratracheal instillation to a 2-mg dose, which is close to the estimated overdose at which macrophage clearance is impared, of each of 3 kinds of particulate matter: crystalline silica, crocidolite asbestos, and titanium dioxide. The lung tissue was evaluated at 3 days, 1 wk, and 1, 3, and 6 mo after exposure. Digital images taken of the lung tissue after processing and staining of the lung sections were examined by the PCM under light microscopy. Evidence of inflammation along with progressive inflammatory changes occurred with crystalline silica and crocidolite, which are well-known hazardous particle types. In contrast, lung tissue from rats exposed to titanium dioxide particles demonstrated a decreasing pattern of histopathological change with increasing retention time. Differences in repair patterns of TiO(2) versus crocidolite and silica following the 2-mg dose exposure suggest that the PCM scoring system may be a useful and sensitive tool for qualitatively evaluating the biological hazards of new particle types, for which no toxicological information exists for low-dose exposure, by using the results from assessment of fibrogenic particle types (such as crocidolite and crystalline silica) as well as particle types with low toxicity (such as TiO(2)) as reference points.
| PBS buffer solutions with different pH values can change porosity of DNA-chitosan complexes
Fukushima, T., T. Hayakawa, et al. (2005), Dent Mater J 24(3): 414-21.
Abstract: We examined the effect of phosphate-buffered saline (PBS) solution with different pH values on the formation of porosity in the DNA/chitosan complexes, and evaluated the intercalation behavior of the complexes. Four different PBS solutions with pH = 6.0, 7.0, 7.4, and 7.8 were used for rinsing water-insoluble DNA-chitosan complexes. All complexes showed high porosities ranging from 83 to 95%. Rinsing with PBS at pH 7.0, 7.4, and 7.8 reduced the porosity of the DNA-chitosan complexes. Re-rinsing with PBS at pH 7.4 reduced the porosity of the DNA-chitosan complex rinsed with PBS at pH 6.0. The appearances for porous formation were influenced by the differences in pH of PBS. Daunorubicin hydrochloride intercalated and bound in the grooves of DNA within all of the DNA-chitosan complexes, indicating that DNA in the complexes maintained its double-stranded helical structure. These results suggested that PBS-rinsed DNA-chitosan complex is promising as a scaffold material in tissue engineering.
| Pectin-chitosan multilayer formation
Marudova, M., S. Lang, et al. (2005), Carbohydr Res 340(13): 2144-9.
Abstract: The deposition of alternating layers of pectin and chitosan at a solid surface was studied using surface plasmon resonance. The binding of biopolymer to the surface was irreversible over the time scales examined. The deposition was dependent on the flow rate through the measurement cell with mass transport limitation at lower flow rates. The thickness of the deposited layer was dependent on the biopolymer concentration and was particularly marked for pectin. This was consistent with a process of initial attachment, followed by a slower structural rearrangement, which was inhibited at high initial surface concentrations of adsorbed biopolymer. Sequential deposition resulted in the formation of multilayers with an essentially linear growth rate.
| PEG- and peptide-grafted aliphatic polyesters by click chemistry
Parrish, B., R. B. Breitenkamp, et al. (2005), J Am Chem Soc 127(20): 7404-10.
Abstract: Novel aliphatic polyesters with pendent acetylene groups were prepared by controlled ring-opening polymerization and subsequently used for grafting poly(ethylene glycol) and oligopeptide moieties by the Cu(I)-catalyzed addition of azides and alkynes, a type of "click" chemistry. These aliphatic polyesters possess an acetylene graft density that can be tailored by ring-opening copolymerization of alpha-propargyl-delta-valerolactone (1) with epsilon-caprolactone. Since the mild conditions associated with the click reaction are shown to be compatible with the polyester backbone, this method is a generally useful means for grafting numerous types of functionality onto aliphatic polyesters. The amphiphilic graft polyesters prepared in this study are shown to be biocompatible by in vitro cytotoxicity evaluation, suggesting their suitability for a range of biomaterial applications.
| PEG-appended beta-(1-->3)-D-glucan schizophyllan to deliver antisense-oligonucleotides with avoiding lysosomal degradation
Karinaga, R., K. Koumoto, et al. (2005), Biomaterials 26(23): 4866-73.
Abstract: Schizophyllan is a natural beta-(1-->3)-d-glucan existing as a triple helix in water and as a single chain in dimethylsulfoxide (DMSO). As we already reported, when a homo-polynucleotide [e.g., poly(dA) or poly(C)] is added to the schizophyllan/DMSO solution and subsequently DMSO is exchanged for water, the single chain of schizophyllan forms a complex with the polynucleotide. One of the potential applications for this novel complex is an antisense-oligonucleotide (AS ODN) carrier. The present paper describes a modification technique that enabled us to introduce PEG only to the side chain of schizophyllan. This technique consisted of periodate oxidation of the glucose side chain and subsequent reaction between methoxypolyethylene glycol amine and the formyl terminate, followed by reduction with NaBH4. Subsequently, we made a complex from PEG-appended schizophyllan and an AS ODN sequence, and carried out an in vitro antisense assay, administrating the AS ODN complex to depress A375 c-myb mRNA of A375 melanoma cell lines. The PEG-SPG/AS ODN complex showed more enhanced antisnese effect than naked AS ODN dose, i.e., the same level as that of RGD-appended SPG. Here, the RGD system has been shown one on the most effective AS ODN carrier (Science 261 (1993) 1004-1012). When we added nigericin to the assay system, the antisense effect was not affected in the PEG-SPG system, on the other hand, it was almost eliminated in the RGD system. Nigericin is well known to interrupt transport from endosome to lysosome. Therefore, the difference between the PEG and RGD complexes indicates that, in the PEG system, AS ODN was able to escape from lysosomal degradation. The present work has thus proposed a new strategy to delivery AS ODN using schizophyllan as a new carrier.
| PEG-grafted chitosan as an injectable thermosensitive hydrogel for sustained protein release
Bhattarai, N., H. R. Ramay, et al. (2005), J Control Release 103(3): 609-24.
Abstract: Thermosensitive polymer hydrogels that undergo a sol-to-gel transition in response to temperature changes are of great interest in therapeutic delivery and tissue engineering as injectable depot systems. A chitosan-based, injectable thermogel was prepared by grafting an appropriate amount of PEG onto the chitosan backbone and studied for drug release in vitro using bovine serum albumin (BSA) as a model protein. When more than approximately 40 wt.% of PEG was grafted to chitosan chains via covalent bonding, the aqueous solution of the resultant copolymer was an injectable liquid at low temperature and transformed to a semisolid hydrogel at body temperature. After an initial burst release in the first 5 h, a steady linear release of protein from the hydrogel was achieved for a period of approximately 70 h. Prolonged quasi-linear release of protein up to 40 days was achieved by crosslinking the hydrogel with genipin in situ, in a fashion suitable for protein encapsulation while maintaining the injectability of the hydrogel. The crosslinkage transformed the copolymer from a physical gel to an insoluble chemical gel and substantially reduced the initial burst release of protein. Both high performance liquid chromatography (HPLC) and gel electrophoresis indicated that the primary structure of BSA released from the hydrogels with or without genipin-crosslinking was generally conserved. The hydrogel can be prepared in solutions with a physiological pH, allowing the safe incorporation of bioactive molecules for a broad range of medical applications, particularly for sustained in vivo drug release and tissue engineering.
| PEG-variant biomaterials as selectively adhesive protein templates: model surfaces for controlled cell adhesion and migration
Tziampazis, E., J. Kohn, et al. (2000), Biomaterials 21(5): 511-20.
Abstract: Our study focused on the role of poly(ethylene glycol) (PEG) in actively regulating the biological responsiveness of protein-adsorbed biomaterials. To this end, we designed PEG-variant biomaterials from a family of tyrosine/PEG-derived polycarbonates to present surfaces ranging from low to intermediate levels of PEG concentration, below the PEG level requisite for complete abolition of protein adsorption. We analyzed the effect of PEG concentration on the amount, conformation and bioactivity of an adsorbed model protein, fibronectin, and on the attachment, adhesion strength and motility of L929 fibroblasts. Our results demonstrate that low levels of PEG can regulate not only the extent but also the conformation and specific bioactivity of adsorbed fibronectin. As the PEG concentration was increased from 0 to 6 mol%, the amount of adsorbed fibronectin decreased linearly yet the fibronectin conformation was altered such that the overall bioactivity of adsorbed fibronectin was uncompromised. We report that the degree of cell attachment varied with PEG concentration in a manner similar to the dependence of fibronectin bioactivity on PEG. In contrast, the nature of cell adhesion strength dependence on PEG paralleled the pattern observed for fibronectin surface concentration. Our studies also indicated that the rate of cell migration was inversely correlated with PEG concentration over a narrow range of PEG concentration. Overall, these results highlight the striking ability of PEG-variant biomaterials to systematically regulate the behavior of adsorbed cell adhesion proteins and, consequently, effect cell functions.
| PEGylation of octreotide: I. Separation of positional isomers and stability against acylation by poly(D,L-lactide-co-glycolide)
Na, D. H. and P. P. DeLuca (2005), Pharm Res 22(5): 736-42.
Abstract: PURPOSE: To investigate the mechanism by which polyethylene glycol (PEG) conjugation (PEGylation) prevents the acylation of octreotide by poly(d,l-lactide-co-glycolide) (PLGA). METHODS: Octreotide was chemically modified by reaction with succinimidyl propionate-monomethoxy PEG. Each PEGylated octreotide species with different PEG number and modified position was separated by reversed-phase high-performance liquid chromatography (RP-HPLC) and characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) with endoproteinase Lys-C digestion. Acylation of octreotide and PEGylated octreotides was observed with hydrophobic and hydrophilic PLGA. RESULTS: Two mono- and one di-PEGylated octreotides were separated by RP-HPLC. MALDI-TOF MS of the PEGylated products after Lys-C digestion at different pH revealed that the two mono-PEGylated octreotides were modified at the N-terminus and Lys(5) residue, respectively. The interaction of octreotide with PLGA involved an initial adsorption followed by acylation and the subsequent release of octreotide and acylated octreotide. The initial adsorption of octreotide was dependent on the acidity of PLGA. PEGylation of octreotide significantly inhibited the initial adsorption and acylation by PLGA. In particular, the acylation could be completely prevented by mono-PEGylation at the N-terminus of octreotide. CONCLUSIONS: This study shows that the N-terminus of octreotide is the preferred PEGylation site to prevent acylation in degrading PLGA microspheres. The mono-N-terminally PEGylated octreotide may possibly serve as a new source for somatostatin microsphere formulation.
| PEGylation of octreotide: II. Effect of N-terminal mono-PEGylation on biological activity and pharmacokinetics
Na, D. H., K. C. Lee, et al. (2005), Pharm Res 22(5): 743-9.
Abstract: PURPOSE.: To determine the optimal polyethylene glycol (PEG)-conjugate of octreotide by evaluating the effects of PEGylation chemistry on the biological activity and pharmacokinetic properties. METHODS.: Octreotide was chemically modified by reaction with succinimidyl propionate monomethoxy PEG (SPA-mPEG, molecular weight 2000) or succinimidyl butyraldehyde-mPEG (ALD-mPEG, molecular weight 2000 and 5000). The structural conformation of PEG-octreotides was evaluated by circular dichroism (CD), the biological activity was assessed by measuring the decrease of serum insulin-like growth factor-I levels in rats, and a pharmacokinetic study was performed after subcutaneous administration in rats. The stability against acylation was investigated with poly(D,L -lactide-co-glycolide) (PLGA). RESULTS.: ALD-mPEG was site-specific in PEGylating octreotide at the N-terminus. The mono-PEG-octreotides prepared with ALD-mPEG (mono-ALDPEG-octreotide), which alkyl bond preserves the amine's positive charge, showed complete preservation of biological activity, whereas the PEG-octreotides prepared with SPA-mPEG showed lower activity. In the CD analysis, the spectra of the mono-ALDPEG-octreotides were nearly superimposable with that of native octreotide. The mono-ALDPEG-5K-octreotide showed significantly improved pharmacokinetic properties compared with mono-ALDPEG-2K-octreotide as well as native octreotide. Both mono-ALDPEG-2K- and mono-ALDPEG-5K-octreotides were stable against acylation by degrading PLGA. CONCLUSIONS.: The mono-PEGylation of octreotide at N-terminus with ALD-mPEG produced a conjugate that is biologically and structurally active and stable against acylation by PLGA, and therefore it may serve as a candidate for somatostatin microsphere formulations.
| Peptides as novel smart materials
Fairman, R. and K. S. Akerfeldt (2005), Curr Opin Struct Biol 15(4): 453-63.
Abstract: Important challenges in biomaterials design include predicting the formation of large-scale self-assembled structures based on local atomic-level interactions and then endowing such structures with the ability to respond sensitively to environmental cues. This responsiveness is referred to as smartness. With the advent of key technological advances in imaging, peptides have recently begun to be exploited for their potential use as biomaterials, such as filaments and fibrils, hydrogels, surfactants and peptide hybrids. Peptides offer attractive features, principally because of our detailed understanding of their ability to fold into specific structures, and the rich chemistry with which their structure and function can be manipulated for environmental response.
| Peptides derived from human decorin leucine-rich repeat 5 inhibit angiogenesis
Sulochana, K. N., H. Fan, et al. (2005), J Biol Chem 280(30): 27935-48.
Abstract: Excessive angiogenesis is involved in many human diseases, and inhibiting angiogenesis is an important area of drug development. There have been conflicting reports as to whether decorin could function as an angiogenic inhibitor when used as an extracellular soluble factor. In this study, we demonstrated that not only purified decorin but also the 26-residue leucine-rich repeat 5 (LRR5) of decorin core protein functions as angiogenesis inhibitor by inhibiting both vascular endothelial growth factor (VEGF) and basic fibroblast growth factor-induced angiogenesis. Peptide LRR5 inhibited angiogenesis through multiple mechanisms, including inhibiting VEGF-stimulated endothelial cell (EC) migration, tube formation on Matrigel, cell attachment to fibronectin, as well as induction of EC apoptosis without significantly affecting their proliferation. We further demonstrated that different subregions of LRR5 inhibited different aspects of angiogenesis, with the middle region (LRR5M, 12 residues) inhibiting endothelial cell tube formation up to 1000 times more potently than LRR5. Although the C-terminal region (LRR5C) potently inhibited VEGF-stimulated endothelial cell migration, the N-terminal region (LRR5N) is as active as LRR5 in inhibiting endothelial cell attachment to fibronectin. Although both LRR5M and LRR5N induced EC apoptosis dose-dependently similar to LRR5 through a caspase-dependent pathway, LRR5C has no such function. We further showed that the inhibition of tube formation by LRR5 and LRR5M is linked with their ability to suppress VEGF-induced focal adhesion kinase phosphorylation and the assembly of focal adhesions and actin stress fibers in ECs, but not their ability to interfere with endothelial cell attachment to the matrix. Circular dichroism studies revealed that LRR5 undergoes an inter-conversion between 3(10) helix and beta-sheet structure in solution, a characteristic potentially important for its anti-angiogenic activity. Peptide LRR5 and its derivatives are therefore novel angiogenesis inhibitors that may serve as prototypes for further development into anti-angiogenic drugs.
| Perceived side effects of biomaterials in prosthetic dentistry
Hensten-Pettersen, A. and N. Jacobsen (1991), J Prosthet Dent 65(1): 138-44.
Abstract: The present questionnaire survey of side effects of biomaterials in prosthodontics had a response rate of 64%. There were occupational health problems associated with a variety of dental materials, especially acrylic resins, eugenol-containing materials, and elastomer impression materials. Most reactions were mild to moderate dematoses of the fingers or hands, but one prosthodontist had to cease practice due to a severe allergic reaction to acrylic resin materials. Of the respondents, 8% had experienced reactions to latex gloves. Nondermatologic reactions seemed to be transient, affecting the eyes, respiratory pathways, or occasionally causing generalized symptoms. These reactions were mainly attributed to vapors from acrylic resin monomers or cyanoacrylates. Adverse reactions in patients, tentatively estimated to be one out of 300, were observed by 40% of the prosthodontists, mostly as intraoral reactions. Acrylic resins, eugenol-containing cements, base metal alloys, mercury, gold, polyether/epimine based materials, and tissue conditioners were cited as causes. Skin contact with the dentists' latex gloves elicited extraoral reactions in some patients.
| Perforated demineralized bone matrix: a new form of osteoinductive biomaterial
Gendler, E. (1986), J Biomed Mater Res 20(6): 687-97.
Abstract: This study was undertaken to evaluate a new osteoinductive material--perforated decalcified bone matrix (PDBM). Subcutaneous implantation of PDBM induces multiple centers of endochondral osteogenesis with subsequent resorption of bone matrix and its replacement by new bone. PDBM should therefore prove useful as a research model to study osteoinduction and in the clinical situation in orthopedic and reconstructive surgery for the filling of bone defects and stimulation of fracture healing.
| Performance of dental biomaterials: conference report
Anusavice, K. J. and W. G. de Rijk (1990), Dent Mater 6(1): 69-72.
Abstract: On August 13-18, 1989, a dental conference, entitled "Dental Biomaterials: Assessment of Performance Based on Engineering and Statistical Methods", was held in Santa Barbara, California. This conference was sponsored by the Engineering Foundation with co-sponsorship by the United States Army Institute of Dental Research, the United States Naval Dental Research Institute, Block Drug Co., Dentsply International, and the National Institute of Standards and Technology. The objective of this conference was to explore engineering and statistical methods for assessing the resistance of dental biomaterials to structural degradation and failure and for predicting the relative reliability of dental restorations and prostheses under clinical conditions. The conference was designed to evaluate the merits of established and new technology relative to the performance of dental materials. Analytical and experimental methods included fracture mechanics, conventional mechanical tests, adhesion tests, fractographic analysis, finite element analysis, statistical analysis, tribology, image analysis, x-ray diffraction, and scanning tunneling microscopy. The central theme was the development of a systematic approach to predict material performance under clinical conditions based on stress analysis, correlation of clinical data with in vitro data, and fracture surface characterization based on qualitative and quantitative methods. Supported in part by NIDR Grant No. DE06672.
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