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Biomedical subjects

K Ikebe

Publications and source records attributed to K Ikebe.

At least 19 recordsLinked to original sources
PubMed2006

Effect of adding impression material to mandibular denture space in Piezography.

The purpose of the study was to examine the effect of adding impression material on denture space using a piezographical record. Subjects were ten voluntary edentulous patients, aged from 61 to 84 years old. A maxillary trial denture with anterior artificial teeth and a mandibular base plate with a keel were inserted into the oral cavity. Three ml of tissue-conditioning materials was injected on the base plate for each trial. Afterwards, the patients were instructed to pronounce various phonemes, so that tongue, cheeks and lips conformed to the denture space. The impression complexes were cut at the level of the estimated occlusal plane. Occlusal analogues were made by duplicating the impression complexes. Measurements were performed for five analogues from the first to fifth additions for each subject. The data were compared using analysis of variance (ANOVA), and a Friedman's test followed by a Bonferroni test for multiple comparisons with a level of significance at 5%. At the molar and premolar positions, the bucco-lingual widths of the occlusal table increased significantly at incremental injection of impression materials from P1 to P4. The midpoints of the analogues were located at a distance of 1.5 mm buccally at the molar position and at a distance of 1.9 mm buccally at the premolar position from the top of the alveolar crest, independent of the addition of impression material. It was concluded that denture space was regulated by volume of material and was located slightly on the buccal side from the crest of the residual alveolar ridge.

Aged↗
PubMed2006

Influence of abutment height on strain in a mandibular overdenture.

The purpose of this study was to investigate the influence of coping heights on the strain around the abutment teeth and at the middle part of mandibular overdentures, using strain gauges. A mandibular edentulous model with a silicone artificial mucosa of thickness 2 mm was made. Two artificial roots were embedded on both sides in the canine position. The coping had a dome-shaped upper surface at a height of 0, 2, 4 and 6 mm. On the lingual polished surface of the overdenture, three strain gauges were attached in the left canine position at the vertical level corresponding to the top of the 6, 4 and 2 mm copings and two strain gauges were attached in the middle section (upper and lower). A vertical loading of 49 N was applied on the occlusal surface of first premolar, first molar and second molar. When loading on the first premolar adjacent to an abutment, the largest tensile strain was observed on the overdenture surface close to the top of each coping, independent of coping heights. When loading on the first premolar on the opposite side, the tensile strains around the coping were remarkably smaller. In the middle part of the overdenture, the compressive strains became larger by reducing the coping height or loading on distal point. The largest tensile strain was observed on the overdenture surface close to the top of copings, independent of coping heights.

Compressive Strength↗
PubMed2006

Association of candidal activity with denture use and salivary flow in symptom-free adults over 60 years.

The purpose of this study was to examine the amount of palatal mucosa Candida species associated with denture use and stimulated salivary flow in symptom-free adults over 60 years. The subjects were 351 (189 men and 162 women) independently living elderly people with a mean age of 66.7 +/- 4.3 (SD) years. Candidal activity of palatal mucosa was evaluated by the pH change in the medium that was associated with the acid production of the yeast. Subjects whose stimulated salivary flow rate was less than 0.5 ml/min were placed in the hyposalivation group. A multiple logistic regression analysis was used to determine if an independent variable was statistically significant after controlling for other variables. Candidal activity of the palatal mucosa was significantly associated with the dental status of the maxillae (Kruskal-Wallis test, P < 0.001), but was not significantly associated with age or drug intake. In maxillary denture wearers, Candidal activity of palatal mucosa had a significantly positive correlation with candidal activity of tissue fitting surfaces of maxillary dentures (r = 0.806, P < 0.001). A multiple logistic regression analysis showed that high candidal activity of the palate was significantly associated with being male and wearing maxillary removable dentures. Stimulated salivary flow rate was likely to be negatively related to high candidal activity (P = 0.07). This study suggests that the activity of Candida species in the oral cavity is associated with the wearing of removable dentures and stimulated salivary flow, independent of age or gender even in the relatively healthy elderly.

Aged↗
PubMed2006

Prevalence of root caries in a selected population of older adults in Japan.

In this study, the prevalence of root caries in a sample of Japanese elders was investigated along with various aetiological factors. Two hundred and eighty-seven independently living elderly people over the age of 60 years were examined for the prevalence of active, inactive, and filled root lesions as well as the number of teeth. General health, oral status and brushing habits were surveyed, and salivary flow was determined in terms of flow rate and subjective feeling of dry mouth during eating. About 39% of the subjects had one or more decayed roots and 53.3% had at least one decayed or filled lesion. Root caries was seen most frequently on canine teeth followed by the first premolar. The number of decayed or filled lesions increased with increasing number of residual teeth (Kruskal-Wallis test, P = 0.033), however, there was no association between the proportion of teeth with root decay and the number of teeth. For subjects with 20 or more teeth, the number of decayed roots is likely to be lower in subjects who reported brushing frequently (P = 0.058), and higher in subjects with low salivary flow (P = 0.059) or subjective feeling of dry mouth (P = 0.052) (Chi-squared). The presence of decayed lesions is likely to be related to dry mouth (P = 0.057, odds ratio 3.13) and brushing frequency (P = 0.088, odds ratio 1.76) (Multiple logistic regression analysis). The results indicate a high frequency of root surface caries in this Japanese community-dwelling older population. Oral hygiene status and low salivary flow or perceived dry mouth were potential risk factors for disease.

Age Distribution↗
PubMed2004

Antioxidant effect of MCI-186, a new Free-Radical scavenger, on ischemia-reperfusion injury in a rat hindlimb amputation model.

BACKGROUND: A newly synthesized free-radical scavenger, MCI-186 (3-methyl-1-phenyl-2-pyrazolin-5-1), was recently approved in Japan for treating acute brain infarction. The purpose of this study was to investigate whether or not MCI-186 is effective in reducing ischemia-reperfusion injury in the extremities. MATERIALS AND METHODS: Warm ischemia was sustained for 4 hours. The animals were divided into 4 groups: (1) sham group, (2) control group (saline injection), (3) MCI group (MCI-186 injection), and (4) EPC group (EPC-K1 [(l-ascorbic acid 2-[3,4-dihydro-2, 5,7,8-tetramethyl-2-(4,8,12-trimethyltridecyl)-2H-1-benzopyran-6-yl hydrogen phosphate] potassium salt], a hydroxyl-radical scavenger, injection). Wet and dry (W/D) weights of the gastrocnemius and tibialis anterior muscles, muscle contractile function, and serum levels of creatine phosphokinase (CPK), lactate dehydrogenase (LDH), glutamic oxaloacetic transminase (GOT), and mitochondrial glutamic oxaloacetic transminase (GOT-m) were measured after 24 h of reperfusion. The cytotoxic aldehydes malondialdehyde and 4-hydroxy-2-nonenal as indices of lipid peroxidation (LPO), and neutrophil-specific enzyme myeloperoxidase (MPO) as an index of neutrophil infiltration, were measured in the gastrocnemius muscle. RESULTS: Contractile functions in the MCI and EPC groups were significantly better than in the control group. In the tibialis anterior muscle, the contractile function was better in the MCI group than in the EPC group. W/D ratios and serum levels of CPK, LDH, GOT, and GOT-m were lower in the sham and MCI groups than in the control group. Levels of LPO and MPO activity were significantly lower in the MCI and EPC groups than in the control group. Histological findings demonstrated that inflammatory tissue reactions rarely occurred in the MCI group. CONCLUSION: MCI-186 is effective in preventing ischemia-reperfusion injury in extremities. MCI-186 seems to have promise as a therapeutic agent, because it prevents ischemia-reperfusion injury even in the tibialis anterior muscle, which contains fast-twitch glycolytic fibers, known to be very susceptible to ischemic insult.

Amputation, Surgical↗
PubMed2004

Effect of magnetic attachment with stress breaker on lateral stress to abutment tooth under overdenture.

Recently, a newly developed magnetic attachment with stress breaker was used in retentive components in overdentures. Excessive lateral stress has a more harmful effect on natural teeth than axial stress, and the magnetic attachment with stress breaker is expected to reduce lateral forces on abutment teeth and protect it teeth from excessive stress. However, the properties of this retainer have not yet been determined experimentally. This study compares the lateral forces on abutment teeth for three retainers under loading on the denture base in a model study. A mandibular simulation model is constructed to measure lateral stress. Three types of retentive devices are attached to the canine root. These devices include the conventional root coping, the conventional magnetic attachment and the new magnetic attachment with stress breaker. For each retentive device, load is generated on the occlusal table of the model overdenture, and the lateral stress on the canine root and the displacement of the overdenture measured. The magnetic attachment with stress breaker does not displace the denture and exhibits lower lateral stress in the canine root than conventional root coping and magnetic attachments.

Acrylic Resins↗
PubMed2003

Association between masticatory performance and maximal occlusal force in young men.

The purpose of this study was to examine the relationship between masticatory performance and maximal occlusal force in dentate subjects, using test foods of varying hardness. Subjects were 20 young males with natural dentitions. Gummy jellies with two different degrees of hardness have been used as test foods to evaluate masticatory performance. Masticatory performance was evaluated by the increase of the surface area of expectorated pieces of comminuted gummy jelly that was calculated from the concentration of gelatin. Maximal occlusal force was measured with pressure sensitive sheets (DENTAL PRESCALE 50H R type). The results suggested that maximal occlusal force had a significant positive correlation to the masticatory performance both with soft gummy jelly and hard gummy jelly. The correlation coefficient (r) with hand gummy jelly tended to be larger than with soft gummy jelly.

Adult↗
PubMed2001

Evaluation of the cost for laparoscopic-assisted Billroth I gastrectomy.

BACKGROUND: Despite the rapid spread of laparoscopic gastric surgery in Japan, no one has yet evaluated the costs for this new technique. The aim of this study was to analyze and compare the hospital charges for laparoscopic-assisted gastrectomy with those for conventional open gastrectomy. METHODS: The study included 48 consecutive patients who underwent laparoscopic-assisted Billroth I gastrectomy and 43 who had a conventional open Billroth I gastrectomy for cure of early gastric cancer between May 1994 and April 2000. Hospital charges covered all costs incurred during the hospital stay; they were divided into charges for consultation, prescription, injection, nursing care, operating theater, laboratory, radiology, ward and meal, and others. RESULTS: The patients who underwent laparoscopic gastrectomy were similar to those who had open gastrectomy in terms of symptoms, concurrent illness, operation time, proximal resection margin, number of harvested lymph nodes, and stage of the disease. Hospital stay after laparoscopic gastrectomy was shorter than that after open gastrectomy (16.1 vs 20.5 days, p < 0.01). Charges for nursing care, charges for ward and meal, and total hospital charges were less in the laparoscopic group than in the open group ( yen5800 vs yen8010, p < 0.01; yen461 x 10(3) vs yen512 x 10(3), p < 0.05; yen1336 x 10(3) vs yen1411 x 10(3), p = 0.072). When we compared laparoscopic gastrectomies performed during 1994-96 with those done during 1997-2000, we found a decrease in charges for ward and meal and total hospital charges ( yen498 x 10(3) vs yen421 x 10(3), p < 0.01; yen1390 x 10(3) vs yen1277 x 103, p < 0.01). CONCLUSION: Laparoscopic-assisted Billroth I gastrectomy is less expensive than conventional open Billroth I gastrectomy because both the postoperative recovery period and the hospital stay are shorter. In patients who undergo gastrectomy, the additional costs of the disposable instruments can be fully offset by the lower charges for ward and meal and nursing care associated with laparoscopic gastrectomy.

Aged↗
PubMed2001

Increased ischemia-reperfusion blood flow impairs the skeletal muscle contractile function.

BACKGROUND: The ultimate aim of replantations and transplantations of skeletal muscle is to improve impaired function. The purpose of this study was to examine the contribution of varying durations of ischemia to postischemic blood flow in the skeletal muscle and the contribution of modulation of postischemic blood flow to skeletal muscle function and viability, using an ischemic revascularized hind limb model in rats. MATERIALS AND METHODS: Warm ischemia produced by vascular pedicle clamping was sustained for 90 min, 3 h, or 6 h. Postischemic blood flow was measured by a Doppler flowmeter or microsphere technique. In another series of experiments of 3-h ischemia, either saline or N(G)-methyl-l-arginine acetate (l-NMMA) was infused for the first 2 h of reperfusion. Postischemic blood flow was also measured. Muscle contractile function and viability were determined after 24 h of reperfusion. RESULTS: Postischemic blood flow was significantly increased during the first 10 min of reperfusion in the 90-minute ischemic group and during the first 2 h in the 3-h ischemic group compared with contralateral control blood flow. No significant increase in postischemic blood flow was noted in the 6-h ischemic group. Postischemic blood flow was significantly decreased by the l-NMMA infusion. Contractile function and viability of the tibialis anterior muscle and contractile function of the gastrocnemius muscle in the l-NMMA group were significantly increased. CONCLUSION: Reperfusion blood flow increased time dependently until 3 h of warm ischemia. Hyperemia deteriorated skeletal muscle contractile function, although it was well preserved by l-NMMA infusion to restrict the postischemic hyperemia.

Animals↗
PubMed2001

Effect of perfusion during ischemia on skeletal muscle.

BACKGROUND: Despite the established preservation method for major organs of perfusion followed by immersion at hypothermia, a standard preservation technique for skeletal muscle is still a matter of controversy. The purpose of this study is to examine the effect of perfusion on the preservation of skeletal muscle in amputated limbs. MATERIALS AND METHOD: The rat hindlimb was amputated for perfusion with Euro-Collins (EC) or University of Wisconsin (UW) solution at different perfusion pressures (40 or 100 cm-gravity). After certain ischemic periods (4 or 5 h), the skeletal muscle viability was determined by measuring the tissue content of adenosine triphosphate (ATP). RESULT: The UW solution perfusion group maintained better ATP levels than the EC solution group when the ischemic period was extended to 5 h. The perfusion pressure of 100 cm-gravity was more effective for preserving muscle viability than 40 cm-gravity with both EC and UW solutions. CONCLUSION: UW solution might be adequate to preserve muscle viability and perfusion pressure is recommended at 100 cm-gravity rather than at minimal pressure (40 cm-gravity), which washes out stagnant blood.

Adenosine↗
PubMed2001

Effects of a hydroxyl radical scavenger, EPC-K1, and neutrophil depletion on reperfusion injury in rat skeletal muscle.

Oxygen free radicals (OFR) and neutrophils are potent sources of reperfusion injury. We compared the effect of EPC-K1, a new OFR scavenger, and neutrophil depletion on the reperfusion injury in skeletal muscle, using an ischemic revascularized hindlimb model in rats. Warm ischemia, produced by vascular pedicle clamping, was sustained for 4 h. After 24 h of reperfusion, muscle function and damage were evaluated in 4 groups: a sham operation group, a control study group, a group treated by EPC-K1 (EPC group), and a group that received nitrogen mustard to induce neutropenia (NM group). Both the EPC and NM groups had limited muscle damage compared to the control group. The EPC group preserved muscle function significantly better than the control group and the mean isometric tetanic tension in the EPC group appeared to be higher than that in the NM group. Furthermore, levels of lipid peroxides in muscle and serum, and muscle edema in the EPC group, were significantly lower than in the NM group. Histological examinations supported these results. These findings suggest that limiting OFR generation by EPC-K1 in the early phase of reoxygenation is more potent than depletion of neutrophils in reducing reperfusion injury.

Animals↗
PubMed2001

[Estimation of daily dietary intake of aluminum].

The daily dietary intake of aluminum was estimated through a total diet study from 1996 to 1998. In ten institutes, total diet study samples were prepared and their aluminum concentration was determined. The average daily intake of aluminum was 3.5 mg and the range was 1.8-8.4 mg. The validity of the analytical result was supported by analyses of certified reference materials.

Aluminum↗
PubMed1993

Bending rigidity of composite resin coating clasps.

The purpose of this study is to examine the bending profiles of composite resin coating cast clasps. The cobalt-chromium alloy cast clasps were made using tapered wax pattern. Silane coupling method (Silicoater MD, Kulzer Co.) was used to attach composite resin to metal surface. The breakage and the bending rigidity of composite resin coating clasps were evaluated. Results were as follows: 1) After the repeated bending test to the tips of clasp arm at 10,000 times in 0.25 mm deflection, neither crack on composite resin surface nor separation at resin/metal interface was observed in any specimen. 2) There was no significant difference in the bending rigidity of clasp arms between before and after composite resin coating. From these results, it was demonstrated that the composite resin coating cast clasp was available in clinical cases and coating with composite resin had little influence on the bending rigidity of clasp arms. Therefore, it was suggested that our clasp designing and fabricating system to control the bending rigidity of clasp arms could be applied to composite resin coating clasps.

Chromium Alloys↗
PubMed1992

Clinical application of a newly developed surveying system for designing and fabricating removable partial dentures.

In this paper, some problems in commercially available surveying systems were discussed, and a clinical technique for designing and fabricating clasps by using an improved 'Digital Surveyor' and a computer system were presented. This system has the advantages as follows: (1) morphological factors on abutment teeth could be measured and evaluated using the improved 'Digital Surveyor' and its accessories set, (2) clasps providing with proper mechanical properties according to various conditions in the mouth could be designed and fabricated precisely and easily. It became clear that conventional surveying methods involved empirical rules should be re-examined and replaced by the more rational surveying method like this system.

Computer-Aided Design↗
PubMed1992

Effects of heat treatment on mechanical properties of base metal wrought wire clasps.

The purpose of this study is to determine the effects of heat treatment and soldering on the change of shape and mechanical properties of cobalt-chromium-nickel alloy wrought wire clasps. The change of distance between the tips of the clasp arm was measured and mechanical properties were examined using the bending test. The following results were obtained. 1) By heat treatment at 500-700 degrees C for 10 minutes, bending rigidity and deflection at the proportional limit of the clasp arm increased significantly (p < 0.01), while permanent deformation after the bending test decreased considerably (p < 0.01). Concerning the deformation of clasp arms by heating, the distance between clasp tips increased remarkably above 500 degrees C (p < 0.01). 2) These mechanical properties of clasp arms were improved both by electric resistance soldering with silver solder and by heat treatment at 500 degrees C for 10 minutes after soldering. From these results, it was concluded that electric resistance soldering and adequate heat treatment were very effective to improve the mechanical properties of the clasp arm, especially to increase the deflection at the proportional limit and reduce the permanent deformation.

Chemical Phenomena↗
PubMed1992

Influence of dimensional factors and heat treatment on permanent deformation of wrought wire clasps.

The purpose of this study is to examine the fatigue profiles of wrought wire clasps during the clinical use. Cobalt-chromium-nickel alloy wires were bent into circular beams, which dimensions and fabrication methods were similar to the clinical cases. Deflections of 0.5 mm in a normal direction were applied 10,000 times to the tips of clasp arm and permanent deformations were measured. The following results were obtained. 1) The clasp arms with larger cross sectional diameter, shorter length and smaller radius of curvature showed larger amounts of permanent deformation. 2) The amounts of permanent deformation of the clasp arm remarkably decreased by electric resistance soldering and decreased further more by heat treatment at 500 degrees C for 10 minutes after soldering regardless of the number of deflection. From the results of this study, it was concluded that dimensional factors and heat treatment influenced the permanent deformation of the wrought wire clasps remarkably. Therefore, considering these factors, wrought wire clasps could be designed to reduce permanent deformation.

Chemical Phenomena↗
PubMed1990

Clinical application of electric resistance welding and soldering methods to removable partial dentures.

The joining procedure for uniting metal structures is very important in the construction of removable partial dentures. However, it has several restricted problems in joining wrought wire clasps to rests or major connectors. For example, the base metal wires made of chromium-cobalt alloy are subject to changes in their mechanical properties caused by heating, and damage to acrylic resin materials (denture base and artificial teeth) occurs in the repair of removable partial dentures by using the torch soldering method. In this paper, in order to resolve these problems, an electric resistance welding machine was applied to attach wrought wire components to a removable partial denture framework. This welding machine was used to attach metal structures temporarily to each other, and to solder the welded joint with hard solder. Consequently, some problems of the conventional torch soldering method were improved by using the electric resistance welding and soldering methods. It was suggested that the clinical application of the electric welding and soldering methods was very useful in the construction of removable partial dentures.

Aged↗