Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Pliability”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,063 records · Page 59Linked to original sources
PubMed1997

Limited joint mobility of the ankle in diabetic patients with cutaneous sensory deficit.

Limited joint mobility (LJM) of the ankle joint was measured in 48 diabetic patients classified into three groups: Insulin-dependent diabetes mellitus (IDDM = 15), non-insulin diabetes mellitus (NIDDM = 12) and patients with cutaneous sensory deficit in the foot (CD = 21). Specifically, plantar flexion, dorsiflexion and total range of motion was measured on both feet using goniometric techniques during active and passive movement conditions. No significant bilateral differences were established, therefore values for the right foot were used for statistical analyses. Diabetic patients were matched to 48 non-diabetic controls for age, weight and gender factors. A Semmes-Weinstein monofilament test was used on both feet to assess the integrity of cutaneous sensitivity in all patient and control subjects. Cutaneous sensory deficit patients (CD) had monofilament values greater than two standard deviations below control group mean values. There were no significant differences between the monofilament test values for the IDDM and NIDDM patients and control group data. LJM results indicated both plantar flexion and range of motion in CD patients under active and passive movement conditions were significantly reduced compared to control group data. No differences were observed for any pairwise comparisons between the IDDM and NIDDM groups compared to controls. The data is discussed in terms of the interaction between LJM in the foot and type of diabetic classification.

Ankle Joint↗
PubMed1999

In vivo study of skin mechanical properties in patients with systemic sclerosis.

BACKGROUND: Measurements of skin elasticity are more sensitive than the skin severity score and appropriate for evaluation of sclerodermatous skin. OBJECTIVE: Our purpose was to investigate the mechanical properties of the skin in patients with systemic sclerosis depending on the stage of the disease. METHODS: Seventeen patients, 8 with edematous phase and 9 with indurative phase of skin involvement, and 16 healthy subjects were studied. Clinical scoring of skin thickness and measurements of skin elasticity with a noninvasive suction device (Cutometer) were performed over 11 anatomic regions. RESULTS: Edematous phase was characterized by significantly lower immediate distention (Ue) and final distention (Uf), and higher viscoelastic to elastic ratio (Uv/Ue) of the skin compared with indurative phase, except for the forehead (8 mm probe). The changes in skin mechanical parameters for fingers were identical in both phases. Low values of skin distensibility correlated with severe skin thickness or hidebound skin. Results were influenced by body site and by the diameter of measuring probe used. CONCLUSION: The noninvasive method applied is suitable for objective and quantitative monitoring of skin involvement in patients with systemic sclerosis.

Adult↗
PubMed1998

Contribution of membrane cholesterol to outer hair cell lateral wall stiffness.

The outer hair cell can be divided into three domains: the apex, the base, and the lateral wall. With the use of filipin, a polyene fluorescent antibiotic that binds to cholesterol, we found under fluorescence microscopy that the lateral wall membranes were less intensely stained than the apical and basal membranes. This difference in filipin fluorescence between the lateral walls and the ends diminished when cells were incubated in water-soluble cholesterol before staining, suggesting that exogenous cholesterol enters the lateral wall. Under confocal microscopy, we studied the incorporation pattern of a fluorescent cholesterol analogue, NBD-cholesterol. NBD-cholesterol did not stain the apical membranes whereas it intensely labeled the lateral wall. The micropipette aspiration technique was used to assess the effect of cholesterol on lateral wall stiffness. The lateral wall stiffness parameter of cells treated with water-soluble cholesterol (n = 23) was significantly higher than that of controls (n = 27): 0.76+/-0.24 (mean +/- SD) versus 0.46+/-0.10 (Student's t-test, p < 0.001). In conclusion, cholesterol has different distributions among outer hair cell membranes, and when water-soluble cholesterol is incorporated into the cells, the outer hair cell lateral wall stiffness parameter increases.

Affinity Labels↗
PubMed1997

Mandibular osteotomy fixed with biodegradable plates and screws: an animal study.

The objective of the study was to evaluate the use of a totally biodegradable fixation device in the fixation of mandibular osteotomy in sheep. Mandibular unilateral body osteotomies were fixed with biodegradable self-reinforced poly-L-lactide (SR-PLLA) multi-layer plates and screws in nine sheep. The unoperated sides acted as control. The follow-up times were 6, 12 and 24 weeks, after which radiological, mechanical and histological studies were carried out. An analysis of the implanted material was also carried out. The results showed that the SR-PLLA plates and screws were strong enough to fix the osteotomy and that the osteotomies healed mainly with callus formation. Therefore we conclude that SR-PLLA multi-layer plates and screws can be used together successfully in the fixation of mandibular osteotomies without maxillomandibular fixation. However, before they can be used in humans, the size of the plate and screws should be decreased.

Animals↗
PubMed2000

Investigation into the relationship between the passive flexibility and active stiffness of the ankle plantar-flexor muscles.

OBJECTIVE: The purpose of the study was to investigate the relationship between measurements of passive flexibility and active stiffness of the ankle plantar-flexor muscles. DESIGN: The study was a correlation design. BACKGROUND: Flexibility has passive and active components. Little information is available regarding the relationship of these measurements in terms of the information that they yield on the state of the muscle-tendon unit. METHODS: Free oscillation data representing active stiffness was obtained using applied masses equivalent to 30%, 60% and 90% of the subject's maximal voluntary contraction. The angle of dorsiflexion, representing passive flexibility, was measured in standing using computer digitisation to obtain the angle.Results. Mean active stiffness values were 14280 N/m (30% maximal voluntary contraction), 22260 N/m (60% maximal voluntary contraction) and 28010 N/m (90% maximal voluntary contraction). Dorsiflexion measurement gave a mean of 34.3 degrees (S.D. 4.8). Correlation's obtained for the association between range of motion and active stiffness were r=0.01 (30% maximal voluntary contraction), r=0.09 (60% maximal voluntary contraction) and r=0.04 (90% maximal voluntary contraction). Moderate reliability coefficients of 0.71 (30% maximal voluntary contraction), 0.78 (60% maximal voluntary contraction) and 0.68 (90% maximal voluntary contraction) were obtained. CONCLUSIONS: The results imply that measurements of passive flexibility and active stiffness of the lower leg musculature are independent measures of components of muscle-tendon unit flexibility. RELEVANCE: Flexibility is a construct with different components of measurement. Etiological studies typically relate static flexibility measurements to injury with conflicting outcomes. This study suggests that static and active flexibility measures yield different information about the muscle tendon unit of the ankle plantar flexors, and that researchers should consider this point in the design of etiological studies.

Adult↗
PubMed2000

Technique to measure lumbar curvature in the ergonomic evaluation of chairs: description and validation.

OBJECTIVE: To describe and validate a system to record the lumbar curvature, specially designed for the ergonomic evaluation of chairs. DESIGN: The technique consists of a flexible goniometer and requires a model of lumbar flexion (relationship between length and angle). BACKGROUND: Most of the techniques do not allow using the backrest of the chair or do not record continuously. METHODS: Precision, repeatability and reproducibility of the measurements have been analysed, as well as the lumbar flexion model. RESULTS: A suitable lumbar model of flexion and the repeatability and reproducibility errors obtained are presented. CONCLUSIONS: The linear model is a good one to represent the flexion of the lumbar spine. The measurements are reproducible and the errors are similar or lower than with conventional inclinometers. Relevance The device may help to investigate the relationship between lumbar pain and curvature, and to evaluate the lumbar curvature in sedentary work.

Analysis of Variance↗
PubMed2000

Biomechanical study on the effect of twisted human patellar tendon.

OBJECTIVE: To compare the stiffness and maximum strength between the untwisted and twisted free-tendon. DESIGN: 22 twisted and untwisted sectioned-specimens of human cadaver patellar tendons were used and pulled to failure to obtain load-deformation profiles from which stiffness, maximum load to failure and elastic elongation limit were derived. BACKGROUND: In the reconstruction of the deficient anterior cruciate ligament, the use of the central one-third of the patellar tendon is a well-established procedure in which, prior to insertion, the tendon graft may be twisted to mimic the natural orientation of the anterior cruciate ligament in the knee joint. RESULTS: The untwisted tendons had a mean stiffness of 36.5 kg/mm (SD, 16.6 kg/mm) and maximum load of 165.9 kg (SD, 86.8 kg). With a 90 degrees twist, the average stiffness of the twisted tendon was 66.5 kg/mm (SD, 25.4 kg/mm), with maximum load at 364.5 kg (SD, 109.9 kg), an increase of over 100%. The elastic elongation limit, or allowable elongation before permanent deformation or failure, was significantly larger in twisted tendons by 35%. CONCLUSION: Twisting increased the resistance to deformation of the tendon in this study. Relevance The finding supports the surgical practice of pre-twisting tendon grafts for anterior cruciate ligament reconstruction, based on the premise that a stronger and stiffer graft provides a more favourable outcome.

Adult↗
PubMed2000

Doppler imaging of vibrations as a tool for quantifying first tarsometatarsal joint stiffness.

OBJECTIVE: To assess whether first tarsometatarsal joint stiffness can be measured by Doppler imaging of vibrations and if so, to assess reference values. DESIGN: Repeated in vivo Doppler imaging of vibrations measurements at the first tarsometatarsal joint in healthy persons. BACKGROUND: Clinical hypermobility of the first tarsometatarsal joint is an important factor in a hallux valgus deformity. No objective and non-invasive test is available to quantify first tarsometatarsal joint mobility. Doppler imaging of vibrations, a technique recently developed to measure joint stiffness, might be an effective tool to quantify stiffness of this joint. METHODS: Vibrations were applied to the head of the first metatarsal in 46 feet of 23 healthy subjects and picked up by a transducer at both sides of the first tarsometatarsal joint. A pilot study was performed on three patients with hypermobility of the first tarsometatarsal joint. Measurements are expressed in threshold units related to colour Doppler imaging. RESULTS: The values of the threshold units were found to be very similar in healthy persons, with a good repeatibility; 95% of the healthy persons had a threshold unit below 3.4. No significant difference was found between the left and right foot, or between male and female subjects. Also there was no significant correlation with age or weight of the subjects. In the three patients with first tarsometatarsal hypermobility we found threshold units above 5. CONCLUSIONS: With Doppler imaging of vibrations first tarsometatarsal joint stiffness can be measured in healthy persons in a non-invasive and objective way. In a pilot study, three patients with first tarsometatarsal hypermobility showed lower stiffness values than the healthy subjects. Relevance This study presents a new method for quantification of first tarsometatarsal joint stiffness and provides reference values in healthy persons. First measurements on patients gave promising results to future use of this method for assessment of clinical hypermobility in hallux valgus patients.

Adolescent↗
PubMed2003

Mandibulotomy fixation: a laboratory analysis.

PURPOSE: Mandibulotomy is an access osteotomy technique associated with significant complications. Critical evaluation of available fixation systems is required to aid in the selection of the most stable fixation method. This study was designed to provide data on the stability of traditionally used plating configurations and a low-profile 2.0-mm locking plate (mandibular locking plate, Synthes MLP; Synthes Maxillofacial, Paoli, PA). MATERIALS AND METHODS: An in vitro red oak model was used to evaluate the stability provided by the study fixation devices. Five groups were studied as follows: group 1, two 4-hole 2.0-mm nonlocking miniplates; group 2, two 4-hole 2.0-mm mandibular locking plates; group 3, one 6-hole 2.0-mm mandibular locking plate; group 4, one 6-hole 2.4-mm nonlocking rigid plate; and group 5, control (uncut red oak blocks). Each specimen was tested with vertical loads applied over the osteotomy site. The force-versus-displacement behavior was recorded for each specimen and analyzed statistically. RESULTS: Plate type and configuration affected the resistance to vertical peak load (kilogram/force [kgf]) and the fixation stiffness (kgf/mm). The greatest peak load (58.92 kgf) and stiffness (7.07 kgf/mm) was found with group 2 specimens. The differences in system stiffness were statistically significant (P <.05), as were the peak loads for groups 1, 2, and 3. The control group (nonosteotomized red oak) had markedly higher values of peak load and stiffness (484 kg and 83 kg/mm, respectively). Group 2 specimens exhibited increased resistance to flexion. CONCLUSIONS: Two 2.0-mm locking plates provided the greatest resistance to vertical load.

Biomechanical Phenomena↗
PubMed1997

An in vitro comparison of the mechanical characteristics of three sagittal ramus osteotomy fixation techniques.

PURPOSE: The purpose of this in vitro investigation was to compare the mechanical characteristics of three techniques for the rigid internal fixation of simulated sagittal ramus osteotomies in terms of their ability to resist vertical loads resembling masticatory forces. MATERIALS AND METHODS: Fifteen bovine ribs of similar size and shape were subjected to uniform osteotomies resembling a sagittal ramus osteotomy. They were divided into three groups and fixed with three 2.0-mm bicortical positional screws in an inverted L-pattern, eight monocortical screws and a sagittal strut plate, or a hybrid system using three 2.0-mm bicortical positional screws, five 2.0-mm monocortical screws, and a sagittal strut plate. The repaired ribs were secured in a jig, subjected to vertically deforming forces, and evaluated for yield load, yield point, maximum load, displacement at maximum load, load at 3.0 mm displacement, and stiffness. The various groups were compared statistically with a Scheffe multiple comparison test. RESULTS: No statistically significant differences existed between the positional screw group and the hybrid group (P > .05). No statistically significant differences were noted in yield displacement, yield load, displacement at maximum load, for any of the groups (P > .05). There were differences noted between the monocortical strut group and other groups in maximum load, load at 3.0 mm displacement, and stiffness (P > .05). CONCLUSIONS: The monocortically fixed sagittal strut plate offers less resistance to maximum load and loads at 3.0 mm displacement and is less stiff than either a three-positional screw system or a hybrid system. No differences existed between the three positional screw systems and the hybrid system. However, given the low yield loads and yield displacements, these differences may not be clinically important.

Animals↗
PubMed2003

Rehabilitation of rotator cuff tendinopathy.

Rehabilitation of the dysfunction that is associated with rotator cuff tendinopathy should be based on the evidence known about the pathoetiology of the tendinopathy, what is known about the extent of the local anatomic injury, the local and distant physiological and biomechanical alterations, and on the knowledge developed regarding progressive loading of the injured or altered structures. Prehabilitation, or prospective exercises to minimize future rotator cuff loading stresses, should be included at the end of rehabilitation as part of the return to function.

Humans↗
PubMed2000

Characterisation of tribochemically assisted bonding of composite resin to porcelain and metal.

OBJECTIVE: The fracture of bonded ceramic to metal restorations remains a problem in clinical dental practice. The use of resin based composites to repair such fractures is generally unsatisfactory. Tribochemical technology creates a surface layer of small silica particles fused to the surface substrate. Such a layer potentially improves adhesion of resin to both alloy and porcelain. Adhesion between two substrates is traditionally studied using shear or tensile bond strength tests. However, the highest stress at bond failure may not represent the real bonding characteristics correctly. An alternative method is to describe the bonding characteristics by determining the strain energy release rate for a given interface. This study compares the bonding characteristics of a resin to gold/porcelain interface using a tribochemical coating process with those of a control group using simple gritblasting. METHODS: Pre-cracked specimens were subjected to load-unload cycles using a simple four point bending test and the resultant strain energy release rates were calculated. RESULTS: Tribochemically pretreating the porcelain resulted in a significant increase in the resultant strain energy release rate from 42.72+/-3.65J/m(2) for the controls to 61.35+/-6.26J/m(2). Likewise there was a significant improvement in the strain energy release rate for the gold/composite interface from 27.31+/-3.00J/m(2) to 42.13+/-4.83J/m(2). CONCLUSIONS: Tribochemical technology offers significant potential advantages for clinical dental practice.

Adhesiveness↗
PubMed2000

The effect of postcuring on quantity of remaining double bonds, mechanical properties, and in vitro wear of two resin composites.

OBJECTIVES: To determine the effect of different postcuring methods on degree of conversion, mechanical properties, and in vitro wear of two resin composites (Z100 and Charisma). The postcuring methods involved devices for inlay curing as well as devices present for other purposes in many dental laboratories or dental offices. METHODS: Specimens of the resin composites were initially light cured and then postcured according to one of the following methods: Translux EC handheld curing unit (10min), Translux EC light box (10min), Triad II (10min), 40 degrees C (10min), 70 or 110 degrees C for 10min, 1, 6, or 24h. The properties were determined following storage of the specimens for 1week in water at 37 degrees C. The degree of conversion was determined using transmission IR. The mechanical properties tested were diametral tensile strength, flexural strength, and flexural modulus. In vitro wear was induced by a three-body wear simulator. RESULTS: Most postcuring methods increased degree of conversion of both materials. Postcuring increased the mechanical properties and in vitro wear resistance of Charisma, whereas no effect of postcuring was found on these properties of Z100. CONCLUSION: Postcuring with the use of devices readily available in the dental laboratory and dental office increased the degree of conversion of Z100 and Charisma as well as the mechanical properties and in vitro wear resistance of Charisma. A heat treatment at 110 degrees C for 10-60min was found to be the most promising postcuring method.

Analysis of Variance↗
PubMed2000

Structural reliability of alumina-, feldspar-, leucite-, mica- and zirconia-based ceramics.

OBJECTIVES: The objective of this study was to test the hypothesis that industrially manufactured ceramic materials, such as Cerec Mark II and Zirconia-TZP, have a smaller range of fracture strength variation and therefore greater structural reliability than laboratory-processed dental ceramic materials. METHODS: Thirty bar specimens per material were prepared and tested. The four-point bend test was used to determine the flexure strength of all ceramic materials. The fracture stress values were analyzed by Weibull analysis to determine the Weibull modulus values (m) and the 1 and 5% probabilities of failure. RESULTS: The mean strength and standard deviation values for these ceramics are as follows: (MPa+/-SD) were: Cerec Mark II, 86.3+/-4.3; Dicor, 70.3+/-12.2; In-Ceram Alumina, 429. 3+/-87.2; IPS Empress, 83.9+/-11.3; Vitadur Alpha Core, 131.0+/-9.5; Vitadur Alpha Dentin, 60.7+/-6.8; Vita VMK 68, 82.7+/-10.0; and Zirconia-TZP, 913.0+/-50.2. There was no statistically significant difference among the flexure strength of Cerec Mark II, Dicor, IPS Empress, Vitadur Alpha Dentin, and Vita VMK 68 ceramics (p>0.05). The highest Weibull moduli were associated with Cerec Mark II and Zirconia-TZP ceramics (23.6 and 18.4). Dicor glass-ceramic and In-Ceram Alumina had the lowest m values (5.5 and 5.7), whereas intermediate values were observed for IPS-Empress, Vita VMK 68, Vitadur Alpha Dentin and Vitadur Alpha Core ceramics (8.6, 8.9, 10.0 and 13.0, respectively). CONCLUSIONS: Except for In-Ceram Alumina, Vitadur Alpha and Zirconia-TZP core ceramics, most of the investigated ceramic materials fabricated under the condition of a dental laboratory were not stronger or more structurally reliable than Vita VMK 68 veneering porcelain. Only Cerec Mark II and Zirconia-TZP specimens, which were prepared from an industrially optimized ceramic material, exhibited m values greater than 18. Hence, we conclude that industrially prepared ceramics are more structurally reliable materials for dental applications although CAD-CAM procedures may induce surface and subsurface flaws that may adversely affect this property.

Aluminum Oxide↗
PubMed2000

Flexural properties of fiber reinforced composite using a vacuum/pressure or a manual adaptation manufacturing process.

PURPOSE: This study investigated the influence of fiber content and water storage on the flexural strength of beams made of two fiber-reinforced composites (FRC), the Vectris and the FibreKor system. MATERIAL AND METHODS: A manual adaptation method (FibreKor, n=30) and a vacuum/pressure process (Vectris, n=30) were compared using 25x4x2mm(3) beams. One group of the Vectris (n=10) and the FibreKor beams (n=10) was stored in water for 24h, a further group was thermal-cycled (TC) 6000x5 degrees C/55 degrees C, and a third group was stored in water for 30days at 37 degrees C. All beams were then loaded to failure using a three-point bending test and the flexural strength was calculated. Finally, the fiber volume percent (vol%) was determined. RESULTS: Generally, the flexural strength decreased significantly with increasing storage time independent of the investigated fiber- and/or manufacturing system. With the parameters 24h/TC/30days, the mean of flexural strength for the Vectris beams was 618/579/545N/mm(2), and for FibreKor 585/534/499N/mm(2). A fiber content of 28.1+/-0.4vol% was assessed for the Vectris beams and 12.8+/-0.6vol% for the FibreKor beams. After 24h storage in water, the Vectris and the FibreKor beams demonstrated a statistically significant higher flexural strength than after 30days storage in water. CONCLUSIONS: A vacuum/pressure manufacturing process in contrast to manual adaptation, resulted in a markedly higher fiber content, but did not necessarily lead to significantly higher flexural strength. Not only the fiber content, but also matrix composition as well as the bond between fibers and matrix determined the properties of FRC.

Analysis of Variance↗