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PubMed1995

[A method for determining global migration into model fluids from plastic packaging materials, in accordance with recommendations of the EWG commission].

Samples of polypropylene, polyethylene, polystyrene foils, softened polyvinyl chloride foils and laminates, in which polyethylene or EVA copolymer or SULRYN ionomer formed the inner layer were subjected to tests for determination of the global migration to aqueous fluids using model methods: chamber test, bag test, immersion test and lining test. The tested materials comprised 37 samples of packaging materials. The tested samples were not exceeding the range of permitted global migration into aqueous model fluids as recommended by the EEC directives. The obtained results fell significantly below the accepted limit of 10 mg/dm2.

Food Contamination↗

PubMed1999

Thrombogenicity testing of central venous catheters in vitro.

To date there have been no standard methods for assessing the thrombogenicity of central venous catheters. A procedure for testing the thrombogenicity of intravenous lines such as the silver-impregnated catheter by continuous blood flow in vitro was therefore developed. For this test, fresh blood was drawn from healthy human donors and anti-coagulated with sodium citrate (1:9). All material tested (catheter tubes with and without silver manufactured in the same way, polyethylene tubes and tubes with potentially thrombogenic material) were perfused through their lumen with anticoagulated blood for up to 31 hours. Blood samples were collected at different times from the test system at sites before and after the perfusion of the test catheters. The hemoglobin concentration, erythrocyte, leukocyte and thrombocyte counts and markers for thrombin activation (thrombin-antithrombin III-complex, F1 + 2)-prothrombin fragments) and for hyperfibrinolysis (d-dimers) were determined. No thrombin activation or signs of hyperfibrinolysis were detected in any material tested. Polyethylene tubes were found to cause hemolysis, as shown by a decrease in hemoglobin content from 15 g% to 4.5 g%. Tecothane tubes with and without silver did not induce hemolysis.

Antithrombin III↗

PubMed1999

Three-body wear associated with three ceramics and enamel.

STATEMENT OF PROBLEM: Wear of human enamel is a clinical concern whenever opposing teeth need to be restored using ceramic restorations. PURPOSE: This in vitro study investigated wear of human enamel and 3 dental ceramics: a conventional porcelain (Vitadur Alpha), a low-fusing hydrothermal ceramic (Duceram-LFC), and a machinable ceramic (Vita Mark II) in a 3-body wear test. MATERIAL AND METHODS: Thirty pairs of tooth-ceramic specimens were tested in a dental wear machine, under a standard load (40 N), rate (80 cycles/minute), and for 25,000 cycles in a simulated food slurry medium. Amount of wear was determined by measuring the height loss of the tooth and depth of wear track of the ceramic materials. Analysis of variance (ANOVA) was used to analyze the data, followed by Bonferroni multiple comparisons method to produce sets of simultaneous 95% confidence intervals. RESULTS: ANOVA revealed significant differences between the groups for both enamel wear (P =. 002) and ceramic wear (P <.001). Further comparisons (95% CI significance level) revealed that the difference in enamel wear produced by Alpha porcelain and Duceram-LFC ceramic material was not statistically significant, whereas that produced by Vita Mark II ceramic was significantly less. Vita Mark II ceramic was significantly more resistant to wear than Alpha porcelain and Duceram-LFC ceramic. Furthermore, Alpha porcelain was significantly more resistant to wear than Duceram-LFC ceramic. CONCLUSION: The abrasiveness of Alpha porcelain and Duceram-LFC ceramic was similar, yet both were significantly more abrasive than Vita Mark II ceramic. In addition, Vita Mark II was the most wear-resistant ceramic and Duceram-LFC ceramic the least resistant.

Analysis of Variance↗

PubMed2004

Does the wear resistance of packable composite equal that of dental amalgam?

BACKGROUND: There is little evidence that packable composites are sufficiently wear resistant to be used as an alternative to amalgam. PURPOSE: The purpose of this study was to evaluate wear rates of packable composites compared with hybrid resin composites and amalgams by an in vitro wear test. MATERIALS AND METHODS: The following composites were used: three packable composites (SureFil, Dentsply/Caulk, Milford, DE, USA; Alert, Pentron Clinical Technologies, Wallingford, CT, USA; and Solitaire, Heraeus Kulzer, Wehrheim, Germany), two hybrid resin composites (TPH Spectrum, Dentsply/Caulk; and Pyramid enamel, Bisco Inc., Schaumburg, IL, USA), and two amalgams (Tytin, Kerr Manufacturing Co., Romulus, MI, USA; and Dispersalloy, Dentsply/ Caulk). Cylindrical Class I cavities prepared on occlusally flattened, extracted human molars were restored with respective materials according to the manufacturers' instructions. Generalized, localized, and antagonistic enamel wear tests were carried out by a University of Alabama at Birmingham (UAB) wear simulator according to previously reported methods. Seven specimens were tested for each group, and the wear depths were measured on profilometric tracings. The data for each wear mode were independently analyzed by one-way analysis of variance and Fisher's exact test (p < or = .05). RESULTS: The generalized wear values for SureFil (7.0 +/- 3.5 microm), Alert (8.6 +/- 1.8 microm), and Pyramid (3.9 +/- 0.5 microm) were not statistically different from those of amalgam materials (Tytin 5.8 +/- 0.7 microm, Dispersalloy 6.0 +/- 0.9 microm) but were different from those of Solitaire (23.9 +/- 2.6 microm) and TPH (30.6 +/- 5.5 microm). The localized wear values for SureFil (19.8 +/- 14.2 microm) and Alert (28.0 +/- 1.6 microm) were significantly smaller than for all other materials. For antagonistic enamel wear, Solitaire exhibited a minimal value (3.4 +/- 0.9 microm), whereas values of SureFil (12.6 +/- 5.6 microm) and Alert (12.0 +/- 6.6 microm) were not statistically different from those of TPH (11.0 +/- 4.0 microm) and amalgams (Tytin 14.5 +/- 4.3 microm, Dispersalloy 7.8 +/- 3.3 microm). CONCLUSIONS: It can be concluded that SureFil and Alert packable composites possess similar wear resistance and abrasiveness to amalgam on the basis of the limitations of this study, which simulated 3 years of clinical wear.

Acrylic Resins↗

PubMed2000

Gel-derived materials of a CaO-P(2)O(5)-SiO(2) system modified by boron, sodium, magnesium, aluminum, and fluorine compounds.

Bioactive glass-ceramic materials of the CaO-P(2)O(5)-SiO(2) system modified by adding boron, magnesium, sodium, fluorine, and aluminum were obtained using the sol-gel method. Gel-derived materials were produced in the pellet form obtained by compression of powders as well as in coatings on glass slides. The materials obtained were examined in vitro with regard to the ability of calcium phosphate layer to form on the material surface as the result of contact with simulated body fluid (SBF). SBF pH changes and calcium solubility in this solution were determined and scanning electron microscopy, energy-dispersive X-ray analysis, and infrared spectroscopy studies were conducted before and after contact of the materials with SBF. The gels modified by aluminum were amorphous, whereas the sodium and fluorine additives promoted the bulk crystallization of gel-derived materials. The ability of calcium phosphates to crystallize on the surface of gel-derived materials depended only slightly on the types of additives applied, and the character of this dependence was different from that observed in melted glasses. Moreover, to estimate the biocompatibility of gel-derived coatings, we examined the proliferation, collagen synthesis, adhesion, and morphology of fibroblasts (NRK cells) cultured in the presence of gel-derived materials. The results of these experiments showed that none of the tested materials significantly reduced any cell function.

Animals↗

PubMed1991

Tissue reaction to intraperitoneally implanted catheter materials.

The limiting factor that introduces long-term complications of intraperitoneal (i.p.) catheters used, for example, with the Programable Implantable Medication System (PIMS) is the encapsulation of the catheter tip with tissues due to tissue reaction. The objective is the development of new catheters for PIMS or other systems for i.p. insulin delivery that allow continued insulin flow. The study is based on two hypotheses: (1) vascularized tissue will grow into a porous end plug mounted at the catheter tip (100-300 microns pore diameter), with sufficient blood supply to carry the insulin to the circulation; (2) use of a narrow pore diameter (25 microns or less) end plug will prevent tissue ingrowth yet allow insulin flow. The biological response to the following materials, all designed for use in catheters, were studied: polyurethane, segmented polyether-urethane, alumina coated on Teflon (proplast regular and micro-pore), pyrolytic carbon, high density polyethylene, ultra high molecular weight polyethylene, hydroxyapatite, bioglass, and expanded Teflon. Some of these materials also are used for several other applications: vascular grafts, in the cardiovascular system, and for dental, orthopaedic, and other purposes. The shape and size of the end plugs made from each of the materials were as similar as possible to minimize size effects. The test materials were implanted i.p. in 12 dogs for a period of 12 weeks. The cylindrical plugs were typically 1.5-2.5 cm long, with an inside diameter of 0.3 cm, and an outside diameter of 0.6 cm. When the explants were retrieved, thin capsules were observed, of varying thickness and blood supply, surrounding the end of the catheters.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1997

Radiopacity of resin-modified glass ionomer liners and bases.

STATEMENT OF PROBLEM: Lining and base materials for restorations have traditionally been autopolymerized and include conventional glass ionomer cements. Light-cured resin-modified glass ionomer cements have recently become available, but a lack of information exists regarding their radiopacity. PURPOSE OF STUDY: In this study the radiopacity of glass ionomer cements was assessed with a standard method that related densitometric measurements to an equivalent thickness of aluminum. MATERIAL AND METHODS: Radiographs were made of specimens with seven materials commonly used as liners and bases: two reinforced zinc oxide-eugenol cements (Kalzinol and Intermediate Restorative Material, De Trey Dentsply), a zinc phosphate cement (SS White, S.S. White Manufacturing), three resin-modified glass ionomer liners (Vitrebond [3M Dental Products], Fuji Lining LC [GC Dental], and Photac-Bond [ESPE Dental Medizin GmbH]), and a conventional glass ionomer liner/base (Ketac-Bond, ESPE Dental-Medizin GmbH), with dentin as a control. The radiopacity of all materials was compared with dentin. RESULTS: Kalzinol had the greatest radiopacity of the materials tested. The glass ionomer cements were substantially less radiopaque than other materials. The conventional glass ionomer cement, Ketac-Bond, was more radiopaque than the three resin-modified glass ionomer cements. Of the three resin-modified glass ionomer materials, Vitrebond was the most radiopaque and Fuji Lining LC was the least radiopaque. CONCLUSION: Future resin-modified glass ionomer materials are recommended to be formulated to increase radiopacity for improved clinical detection.

Absorptiometry, Photon↗

PubMed1992

Surface changes on dental materials. II. The influence of two different dentifrices on surface roughness measured by laser reflexion and profilometer techniques.

Surface changes on eight different dental materials were investigated, using laser reflexion technique and a profilometer. The tested materials were: Acrylic veneers Isosit, Isosit N, K+B+, Multiplus and K+Bpaste Gold Sjödings C Titanium pure non-rolled titanium Ceram a potential ceramic direct filling material The materials were subjected to brushing in a brushing machine, with a toothpaste-water slurry. Two different toothpastes were used separately; Clinomyn and Colgate. The new ceramic material showed no measurable wear by the brushing. All the other materials were affected to some extent. On titanium increasing values of light intensity were obtained thus indicating a smoother surface. Among the veneer materials K+Bpaste was the most wear resistant.

Acrylic Resins↗

PubMedDate not supplied

Simultaneous release of fluoride and aluminum from dental materials in various immersion media.

Since fluoride (F-) and aluminum (Al3+) present anticariogenic properties and F- release from ionomeric materials depends on the media used in the evaluation, this study tested the hypothesis whether release of Al3+ also depends on the testing media. The simultaneous release of F- and Al3+ was assessed over 15 days in three media: (i) distilled and deionized water (H2O), (ii) artificial saliva (AS) and (iii) solutions simulating a cariogenic challenge (pH-cycling in demineralizing and remineralizing solutions, De-Re-). Six cylindrical samples of each tested material (Ketac-Fil, Vitremer, Fuji Ortho LC and F 2000) were prepared and suspended individually in 1.0 mL of each solution. All solutions were changed daily. F- and Al3+ were determined by ion-selective electrode and atomic absorption, respectively. ANOVA showed statistical significance for the interaction of material, time, media (p < 0.05), either for F- or Al3+ release. The resin-modified glass ionomer Vitremer released the highest amount of F- and Al3+ in De-Re- solutions compared to the other materials (p < 0.05); differences among the materials in H2O and AS were statistically consistent. The data suggest that the media used to evaluate the simultaneous release of F- and Al3+ should be taken into account when the anticariogenic potential of different dental materials is assessed.

Acetates↗

PubMed2006

The monocortical critical size bone defect as an alternative experimental model in testing bone substitute materials.

BACKGROUND: Reproducibility and comparability are prerequisites in testing bone substitute materials in an animal study. Various animal test models are used. The standard in testing bone substitute materials is the so-called critical size defect (CSD) model described by Schmitz and Hollinger. In most studies a bicortical (full thickness defect) CSD is used. OBJECTIVE: In this study, monocortical defects (10 x 10 mm) in calvarias of adult pigs were created and compared to examine the spontaneous physiologic healing process and the required criteria for a CSD. STUDY DESIGN: Regeneration of defects, either filled using autogenous bone (group 1) or unfilled (group 2), was evaluated by means of microradiography and light microscopy after 2, 4, 12, 26, and 52 weeks. RESULTS: No complete osseous regeneration was found microradiographically and light microscopically in the control group at week 52 (nonmineralized area: 30% +/- 1.7%; mineralized area: 55% +/- 1.7%; bone marrow area: 15% +/- 1.7%). Defects treated with autogenous bone showed a 100% osseous defect filling after 26 weeks. CONCLUSION: The monocortical CSD fulfills the requirements for a CSD and represents a procedure which can be handled simply for investigations focusing on bone regeneration and testing of bone substitute materials.

Animals↗

PubMed1993

Biocompatibility testing of restorative materials influencing dentin and pulp.

A comparative study was carried out using 27 healthy human bicuspids that had been extracted for orthodontic reasons from adolescents 11-14 years old. A microphotometrical analysis of buccal and lingual odontoblast layer thickness was performed using the SAMBA 2000 system and the results were submitted to statistical comparison. The buccal odontoblast layer (BOL) was found to be thicker than the lingual odontoblast layer (LOL). These results were independent of age, sex, and tooth position in the dental arch. Moreover, a strong relationship existed between the layer thicknesses as linear function on a logarithmic scale. Standards for the evaluation of pulp-dentin biocompatibility are based essentially upon qualitative or semiquantitative histological criteria. A method of quantitative evaluation based upon microphotometrical measurements of the thickness of the buccal odontoblast layer, considered variable, and the lingual odontoblast layer, considered stable, was applied to coronal filling materials that had previously been tested by a classic method. Seventy bicuspids extracted from adolescents 11-14 years of age whose class-V cavities had been filled in situ with one of four restorative materials, and whole residual dentin thickness was less than 750 microns, were divided into two groups: an intermediate-term group (A) and a long-term group (B); both groups were subdivided into four experimental series as a function of test materials. A microphotometrical analysis was carried out using an automatic scanning system (SAMBA 2000) for the quantification of buccal and lingual odontoblast layer thicknesses. The results confirmed that due to the stability of the LOL thickness it may legitimately be used as reference in the study of the analogous BOL thickness.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1984

Comparative in vitro sliding-wear study of conventional, microfilled, and light-cured composite restoratives.

The sliding-wear behavior of a number of commercially available microfilled and light-cured composite restoratives has been investigated and compared with the wear characteristics of conventional composites. The surface profiles of the composite restoratives, both pre- and post-test, have also been examined in order to study material attrition processes. The results indicate that: (1) microfilled composites are significantly more resistant to sliding wear than are restoratives containing conventionally-sized filler particles; (2) light-cured, microfilled composites exhibit a lower rate of sliding wear than do self-curing, microfilled restoratives; and (3) the wear process leads to an increase in surface roughness for all materials tested, but microfilled materials display lower surface roughness values, both before and after sliding-wear tests, than do restoratives containing conventional-sized filler particles.

Chemical Phenomena↗

PubMed1999

A comparison of the shear bond strengths of two glass ionomer cements.

The objective of this study was to determine the in vitro shear bond strength (in megapascals) and location of bond failure with two light-cured glass ionomer resin systems. One system was a hybrid glass ionomer cement with resin (GC Orthodontics, Aslip, Ill), and the other system a glass-filled resin system (Reliance Orthodontic Products, Inc, Itasca, Ill). These systems, Fuji Ortho LC (GC Orthodontics) and Ultra Band Lok (Reliance), respectively, were compared to a light-cured composite resin. Maxillary premolar brackets (n = 200) were bonded to the facial surface of human premolar teeth. The two glass ionomer resin systems were each evaluated by two protocols, one according to the manufacturers' direction plus a variation of their respective technique. The five distinct groups (n = 40) were stored in 37 degreesC distilled water for 30 days and subjected to thermocycling before shear bond strength testing. The findings indicated that large variations existed between the bond strengths of the materials tested. The laboratory shear bond strength of the glass-filled resin glass ionomer cement (Reliance), whether tested in a dry or moist field, was similar to the composite control with all of the previous materials being significantly (P <.01) higher than both the hybrid glass ionomer cement groups (Fuji Ortho LC). However, the hybrid glass ionomer cement with enamel conditioner demonstrated a clinically acceptable mean megapascal value. The Adhesive Remnant Index values ranged from 0.53 to 1.62. The hybrid glass ionomer cement without enamel conditioning recorded the lowest mean adhesive remnant index score and the lowest mean megapascal score. Although both products are glass ionomer resin systems, their individual chemistries vary; this affects their clinical performance. Clinically, it may be suggested that glass ionomers used in a dry field may be beneficial for orthodontic bonding, and that glass ionomer resin systems used in a moist environment need an enamel conditioner.

Acrylic Resins↗

PubMed2005

A biomechanical comparison of arthroscopic sliding and sliding-locking knots.

PURPOSE: To evaluate biomechanical characteristics of 3 arthroscopic sliding and sliding-locking knots and the square knot, the gold standard used in open surgery. TYPE OF STUDY: Biomechanical investigation. METHODS: Four different knot types (Weston, square, Duncan loop, and Nicky's) were tested in 5 configurations in a closed-loop system on a materials testing device. Three of the 5 knots were backed up with 3 reverse half-hitches and alternating posts and all sliding and sliding-locking knots were tied using an arthroscopic technique. Twelve knots of each configuration were tested for loop security with a 7-N preload, and for knot security with load to failure at a strain rate of 1.25 mm/second and cyclic loading of a 30-N force for 50 cycles. RESULTS: No knots subjected to the 7-N preload failed or slipped and all had similar elongation (0.1 +/- 0.1 mm) except Nicky's knot (0.3 +/- 0.2 mm). There was no significant difference in load at failure for the square knot (178 +/- 14 N), the Weston knot backed with 3 half-hitches (168 +/- 14 N), the Duncan loop (160 +/- 20 N), or Nicky's knot (148 +/- 13 N). Most knots with 3 half-hitches failed with rupture at the knot. Under cyclic loading, no knots failed and none elongated greater than an average of 0.3 mm. CONCLUSIONS: All knot configurations maintained high loop security. All sliding and sliding-locking knots backed with 3 half-hitches had load at failure comparable to the square knot. With cyclic load testing, all knots tested elongated minimally. Additionally, this study confirms that all knots, even the sliding-locking Weston knot, are best backed up with 3 half-hitches alternating posts and directions of the throws. CLINICAL RELEVANCE: Sliding and sliding-locking knots are becoming increasingly popular among arthroscopic shoulder surgeons. This study provides a biomechanical basis for the clinical use of these arthroscopic knots and compares them with the gold standard, the open square knot.

Arthroscopy↗

PubMedDate not supplied

[Biomechanical testing of different ventral fixation devices on the bovine lumbar spine].

AIM: The primary stability of ventral fixation systems has been improved over the past years and special implants supporting minimally invasive procedures have been developed. The aim of this study was to analyze the primary stability of several of these implants. METHODS: Thirty (30) lumbar segments from 5 to 7-month-old calves were harvested and tested on a pure moment apparatus (PMA) as well as a modified materials testing machine (MTS) according to the European standard recommendations of Wilke et al. Three different implant systems (MACS, Centaur and Z-plate) were included. ROM, neutral zone and stiffness were tested on the PMA up to 10 Nm, stiffness at an eccentric axial load of up to 1500 N was tested on the MTS. Bone density was investigated for all specimens. Statistical analysis was performed by ANOVA and LSD tests. RESULTS: Primary stability was improved by all fixation devices compared to the physiological specimen. The MACS implant was more stable than the Centaur and Z-plate with the exception of in lateral bending [where the Z-plate was stiffer]. Bone density was comparable in the three different experimental groups. CONCLUSION: Minimal invasive ventral fixation devices are becoming popular. The primary stability of the minimal invasive MACS was comparable to those of other well-known ventral fixation devices of the lumbar spine.

Animals↗

PubMed1984

Abrasion of acrylic veneers by simulated toothbrushing.

The abrasion responses were tested on four acrylic veneer materials, K + B Plus, K + B 75, Isosit, and Ivocron. The studies were performed in two independent research laboratories. Two different brushing machines were used with an abrasive slurry. The results were used for comparing the degree of abrasion for the resin materials. Three analytical methods of measuring the degree of abrasive wear were used: surface profile measurement, microscopic evaluation, and measurement of loss of volume. Isosit showed the best abrasion resistance of the four materials tested.

Acrylic Resins↗

PubMed1997

Biocompatibility of fixation materials in the brain.

Recent clinical reports documenting passive intracranial translocation of microplates and microscrews have prompted concerns regarding brain biocompatibility and neurotoxicity of fixation hardware used in craniofacial surgery. Although the effects of commercially pure titanium. Vitallium (cobalt-chromium-molybdenum), stainless steel, and various alloys have been well assessed in bone and soft tissues, there are no comprehensive studies of these materials in the brain. To investigate this, the biocompatibility of titanium, vitallium, and 316L stainless steel was evaluated in the rabbit brain and compared with silicone elastomer shunt tubing, a material that is used commonly as a neurosurgical implant material with well-established brain biocompatibility. Forty-eight juvenile New Zealand White rabbits were randomly assigned to one of three groups and underwent placement of either commercially pure titanium microscrews, vitallium microscrews, or 316L monofilament stainless steel wire into the parietal region. Silicone elastomer strips of similar size were implanted in the contralateral hemisphere of each rabbit. Animals were assessed daily for signs of neurotoxicity. Rabbits in each group were sacrificed at 2, 4, 8, and 26 weeks following implantation. Brains were sectioned at the implantation site and were examined by means of standard hematoxylin and eosin stains and with immunohistochemical markers sensitive to inflammatory changes in the brain. None of the animals showed any behavioral changes or neurologic deficits suggestive of either systemic or localized toxicity from the implant materials. Silicone clastomer was found to cause the least amount of inflammation relative to other materials tested at all sacrifice points, suggesting that as a standard neurosurgical implant material, it is an appropriate control for studies of brain biocompatibility. At 2 weeks, titanium was found to cause the largest inflammatory response in surrounding brain parenchyma based on analysis of markers for microglial proliferation, gliosis, and leukocyte infiltration. At the 26-week endpoint of our study, the biocompatibility of titanium was nearly equal to the biocompatibility of vitallium based on all studied markers of inflammation. A progressive increase in the inflammatory response surrounding stainless steel implants was noted at 8 and 26 weeks. Relative to all materials studied, at 26 weeks the greatest leukocyte response was found with stainless steel implants. Our results indicate that at the 26-week end-point of our study, titanium and vitallium incited a similar inflammatory response in the rabbit brain that was greater than the response found with silicone elastomer, a standard neurosurgical implant material, but less than that found with stainless steel wire, which is commonly recommended as an alternative fixation material.

Animals↗

PubMed1998

Material properties of commonly-used interface materials and their static coefficients of friction with skin and socks.

Compressive stiffness (CS) of different supporting materials used in prosthetics and orthotics and their static coefficients of friction (COF) with skin and socks were characterized. Materials tested included Spenco, Poron, nylon-reinforced silicone, Soft Pelite, Medium Pelite, Firm Plastazote, Regular Plastazote, and Nickelplast. A displacement-controlled testing device was constructed to assess the CS of 11.1 mm diameter material specimens under cyclic loading (1 Hz) to 220 kPa over 10- and 60-min periods. Results demonstrated local CS ranging from 687 kPa (Poron) to 3,990 kPa (Soft Pelite). To fit the cyclic stress-strain (S-S) data within an error of 4.0 percent full-scale output, the minimum order of fit required for Spenco, Poron, and nylon-reinforced silicone was a third-order polynomial; for Soft Pelite, Medium Pelite, Firm Plastazote, and Regular Plastazote, a second-order polynomial; and for Nickelplast, a linear fit. For all materials, the nonrecovered strains were related to loading time using an exponential fit. A biaxial force-controlled load applicator device was used to assess COF at skin-material, sock-material, and skin-sock interfaces for shear forces of 1 to 4 N applied to a 10.2 x 7.8 mm loading pad. COFs ranged from 0.48 (+/- 0.05) to 0.89 (+/- 0.09). COFs at skin-material interfaces were significantly (p < 0.05) higher than those at skin-sock interfaces. There was a trend of a higher COF at sock-material interfaces than at skin-sock interfaces. These data are of potential utility in finite element modeling sensitivity analysis of residual limb-prosthetic socket systems or body-orthosis systems to characterize effects of material features on interface pressure and shear stress distributions.

Biocompatible Materials↗