Publications by authors named "Sadami Tsutsumi"

Objective: The aim of this study was to analyze the stability changes in immediately loaded implants by using an in vivo quantitative measurement of micromotion under functional dynamic loading and to verify the sensitivity of Resonance Frequency Analysis (RFA) as compared to that of actual micromotion.

Materials And Methods: The micromotions of immediately loaded implants placed in the tibia of 11 rabbits were monitored using a laser displacement sensor. Functional dynamic loading forces were applied 5 days a week for 6 weeks.

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Purpose: The purpose of this study was to investigate the effects of implant tilting and the loading direction on the displacement and micromotion (relative displacement between the implant and bone) of immediately loaded implants by experiments and finite element analysis (FEA).

Methods: Six artificial bone blocks were prepared. Six screw-type implants with a length of 10 mm and diameter of 4.

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Purpose: This study investigated the effects of bone density and crestal cortical bone thickness at the implant-placement site on micromotion (relative displacement between the implant and bone) and the peri-implant bone strain distribution under immediate-loading conditions.

Methods: A three-dimensional finite element model of the posterior mandible with an implant was constructed. Various bone parameters were simulated, including low or high cancellous bone density, low or high crestal cortical bone density, and crestal cortical bone thicknesses ranging from 0.

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Purpose: Pathologic fracture of the mandible after removal of a lesion historically has been a clinical problem. The present study aimed to evaluate mandibular strength after removal of a lesion and to illustrate the theoretical efficacy of preventive measures against pathologic fracture based on a 3-dimensional finite element (FE) analysis.

Materials And Methods: A computed tomographic (CT)-based FE model of the mandible of a patient with a dentigerous cyst including a third molar was constructed.

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Purpose: The purpose of the present study was to analyze the effect of clenching on the biomechanical response of human mandible and temporomandibular joint (TMJ) to traumatic force by the finite element (FE) method.

Material And Methods: FE models of the mandible and the TMJ in resting and clenching positions were prepared. Distribution and magnitude of von Mises stress were analyzed by applying force as a point load in the symphyseal, canine, body and angle regions of the mandible.

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Purpose: This study investigated the biomechanical behavior of the mandible after marginal resection by tensile test in a human cadaveric mandible and finite element (FE) analysis.

Materials And Methods: Human cadaveric mandibular models after marginal resection were prepared with residual heights of 5, 10, and 15 mm. The strength in each of these mandibular models was examined by tensile testing.

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Since porous and injectable bioceramics have recently been utilized often as scaffolds for bone regenerative medicine, the need for their standardization has increased. One of the standard proposals in ISO/TC150 and JIS has been a draft for characterization of the porous bioceramic scaffolds in both micro- and macro-scopic aspects. ISO/TC150/SC7 (Tissue engineered medical products) has been co-chaired by Professor J E Lemons, Department of Surgery, University of Alabama at Birmingham and Dr R Nakaoka, Division of Medical Devices, National Institute of Health Sciences, Japan.

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Three-dimensional computer models of dental arches play a significant role in prosthetic dentistry. The microfocus X-ray CT scanner has the advantage of capturing precise 3D shapes of deep fossa, and we propose a new method of measuring the three-dimensional morphology of a dental impression directly, which will eliminate the conversion process to dental casts. Measurement precision and accuracy were evaluated using a standard gage comprised of steel balls which simulate the dental arch.

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Development of a rapid and accurate method for visceral fat measurement is an important task, given the recent increase in the number of patients with metabolic syndrome. In this study, we optimized the Fast Low Angle Shot (FLASH) sequence using a binominal radiofrequency excitation pulse, in which the acquisition time is short, and measured changes in the amount of visceral fat in subjects after a period of wearing clothes with a fat-reducing effect during walking. We solved the reproducibility problem associated with the number of slices, and developed automatic measurement software for high-precision separation and extraction of abdominal visceral fat images.

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In compression plating, anatomical reduction and compression across the fracture site are the basic principles necessary to achieve primary bone healing. However, varying amounts of gap at the fracture site frequently occur due to technical pitfalls, such as overbending of the plate and inaccurate reduction, and due to the fracture configuration itself. Little is known as to how fracture gap affects stability of the bone-plate construct.

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Purpose: The purpose of this study was to investigate the biomechanical behavior of miniplate osteosynthesis for fracture of the edentulous mandible with various degrees of atrophy by finite element (FE) analysis.

Materials And Methods: Three-dimensional FE models simulating various atrophic or nonatrophic edentulous mandibles were constructed. The models were divided into 3 groups based on the height: 20 mm, 15 mm, and 10 mm.

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The effect of epigallocatechin-3-O-gallate (EGCG), a major component of green tea, on platelet preservation was evaluated. Single donor platelets (N = 10) were collected and preserved by the standard method. EGCG was added to the platelet concentrates before preservation and then the functional and biochemical parameters were monitored throughout the storage period.

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A fresh osteochondral allograft is one of the most effective treatments for cartilage defects of the knee. Despite the clinical success, fresh osteochondral allografts have great limitations in relation to the short storage time that cartilage tissues can be well-preserved. Fresh osteochondral grafts are generally stored in culture medium at 4 degrees C.

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Objectives: The aim was to assess the effect of trypsin on the transdermal delivery of macromolecules by applying its specific biochemical properties to the stratum corneum of the skin.

Methods: Fluorescein isothiocyanate (FITC)-labelled dextrans (FDs), with molecular weights of 4 to 250 kDa, and FITC-insulin were used as model macromolecules and a model polypeptide, and the in-vitro transdermal permeation experiments, with or without trypsin (0.1-2.

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Purpose: The articular cartilage is a small tissue with a matrix structure of three layers between which the orientation of collagen fiber differs. A diffusion-weighted twice-refocused spin-echo echo-planar imaging (SE-EPI) sequence was optimized for the articular cartilage, and the structure of the three layers of human articular cartilage was imaged in vivo from diffusion tensor images.

Materials And Methods: The subjects imaged were five specimens of swine femur head after removal of the flesh around the knee joint, five specimens of swine articular cartilage with flesh present and the knee cartilage of five adult male volunteers.

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One of the key challenges in employing biomaterials is determining how to fix them into the surrounding tissue. To enhance the interaction with surrounding bone, amorphous hydroxyapatite (HA) was coated onto the surface of the bio-inert poly(vinyl alcohol) hydrogel (PVA-H), as an artificial cartilage material, by a pulsed laser deposition technique. Next we examined the binding effects of the HA thin film (300 nm thick) to the underlying bone using osteoblast proliferation and differentiation.

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A novel nerve guide tube (poly (L-lactic) acid (PLLA)/ polyglycolic acid (PGA)-c-tube) capable of repairing long peripheral nerve injuries in a canine model has been developed. The tube was created by braiding together PLLA and PGA and then coating it with collagen. PLLA was newly added to the formulation to achieve higher sustainability.

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Epigallocatechin-3-O-gallate (EGCG), the major polyphenolic compound present in green tea, has potent anti-oxidant and free radical-scavenging activities. In this study, various concentrations (10, 100, and 1,000 ppm) of EGCG were incorporated into a collagen sponge (CS) in order to investigate its healing effects on full-thickness wounds created in type 2 diabetic mice. After 14 days, the residual wound size of the mice treated with 10 ppm EGCG-incorporated collagen sponge (E-CS) decreased significantly faster than that of the other mice.

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In the diagnosis of dental occlusion, it is necessary to quantitatively measure interocclusal contacts and transfer them to a computer model. In this aspect, three-dimensional computer models of upper and lower dental casts play a significant role. In this study, we proposed a new method to measure occlusal interaction by using a microfocus X-ray CT technique.

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Purpose: Using simultaneous multiple cross-sectional imaging, we imaged four cross sections, including the mandibular midline and the right and left temporomandibular joints, to observe one movement of mouth opening and closing and analyze the movement of the mandible and temporomandibular joints.

Materials And Methods: Four cross sections, including the midsagittal section of the mandible, the sagittal sections of the right and left temporomandibular joints and the horizontal section containing the heads of right and left temporomandibular joints, were imaged simultaneously. The imaging was conducted in 10 male and female volunteers.

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Trypsin has been extensively used in laboratory settings for in vitro epidermal separation and keratinocyte isolation for over 50 years. The aim of this study was to assess the enhancing effect of trypsin on the transdermal delivery of insulin by applying its specific biochemical properties to react with the stratum corneum (SC) of skin. Bovine insulin was used as a model peptide to investigate in vitro permeation through rat skin and in vivo hypoglycemic effects of bovine insulin with or without the trypsin pretreatment.

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Muscular recovery after exercise is an important topic in sports medicine, and accurate and quantitative measurements of changes in muscle are required to assess muscular recovery. In the present study, we report a new analytical method to measure muscular changes quantitatively. The technique consists of three independent methods: image processing of two-dimensional MR images, morphological analysis using three-dimensional MR images, and diffusion tensor MRI.

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The objective of this study is to investigate soft tissue and bone tissue reaction to titanium implants treated by a modified micro arc oxidation (MAO) technique, and analyze the surface components and implant-bone contact ratio by animal experiments to evaluate the osseointegration condition of implants with this modified MAO surface. MAO titanium plates were installed subcutaneously in rabbits. Tissue reaction was evaluated by HE sections.

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Localized drug delivery from drug-eluting stents has been accepted as one of the most promising treatment methods for preventing restenosis after stenting. However, thrombosis, inflammation, and restenosis are still major problems for the utility of cardiovascular prostheses such as vascular grafts and stents. Epigallocatechin-3-O-gallate (EGCG), a major polyphenolic constituent of green tea, has been shown to have anti-thrombotic, anti-inflammatory and anti-proliferative activities.

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Using functional MRI and diffusion tensor tractography, we studied the topographical relation of hand and foot fibers of the corticospinal tract within the internal capsule to verify the recent unexpected finding by Holodny et al., who reported that hand fibers are located anterolateral to foot fibers, not anteromedial as is currently believed. The location of hand fibers with respect to foot fibers was anterolateral in four participants, posterolateral in two, and anteromedial in one of seven participants examined.

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