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Biomedical subjects

K Tanne

Publications and source records attributed to K Tanne.

At least 55 records · Page 3Linked to original sources
PubMed2001

The nature of human craniofacial growth studied with finite element analytical approach.

The purpose of this study was to elucidate the nature of human craniofacial growth by means of finite element method (FEM), and to compare the results with the current concept derived from morphometric studies with roentgenographic cephalometry (RCM). Lateral cephalograms were taken of 20 males and 20 females, and traced on acetate paper. On the tracing, the craniofacial complex was divided into seven areas or elements. Growth analysis was executed with FEM for changes in the size and shape of each area during six developmental periods from 4 to 18 years old. The size change in the male group exhibited a peak from 10 to 12 years old for the cranial base and upper facial skeleton, from 8 to 10 years old for the maxillary complex, and from 12 to 14 years old for the mandible. On the other hand, in the females, the size change was almost invariable from 4 to 12 years old and completed suddenly at 12 years old, which was earlier by a few years than in the males. An interesting finding is that changes in the size and shape were the most substantial in the maxillary complex, followed by those in the mandible, and the smallest in the cranial base and upper facial skeleton. It is shown that growth of the cranial base lasted up to 14 years old and the maxillary complex exhibited the greatest growth changes in the size among various anatomic structures. These findings may provide a new concept of human craniofacial growth, somewhat different from the previously established principles by RCM.

Journal Article↗
PubMed2001

Breadth of the mandibular condyle affected by disturbances of the sex hormones in ovariectomized and orchiectomized mice.

It is well known that the size of the condyle is different between males and females in humans. It has also been documented that ovariectomy (OVX) and orchiectomy (ORX) influence the remodeling of the condylar head in experimental animals. However, influences of sex hormones on the condyle in terms of its breadth have not been examined. With these considerations, this study was designed to examine the breadth of the mandibular condyle in OVX and ORX mice by histomorphometry 8 weeks after surgery. In the OVX mice, the condylar breadth was significantly larger than in the controls, while no significant differences in the breadth were found between the ORX mice and the controls. The thickness of the condylar cartilage layers exhibited similar findings to the breadth of the condyle. On the contrary, the trabecular bone volume was significantly smaller in the OVX and ORX mice than in the corresponding controls, and the difference was more substantial in female mice than in the males. These findings emphasize that a reduction of sex hormone levels, induced by OVX and ORX, significantly influences condylar morphogenesis.

Journal Article↗
PubMed2001

The expression of osteopontin with condylar remodeling in growing rats.

It is suggested that osteopontin may promote osteoclast binding to resorptive sites by interacting with the alphavbeta3 receptor on osteoclasts. However, the role of osteopontin in functional remodeling of bony structures remains unclear. The present study was conducted to examine the distribution of osteopontin on the condyle and explore the role in condylar remodeling in growing rats using an immunohistochemical method. Twenty Wistar strain male rats aged 7, 14, 28 and 56 days were used. In 7- and 14-day-old rats, no immunoreaction to osteopontin was detected in the cartilage cells. In 28-day-old rats initiating mastication, the thickness of condylar cartilage was decreased abruptly as compared to the younger rats. High immunoreaction to osteopontin was found in the cytoplasm of hypertrophic chondrocytes and on the trabecular bone surfaces of primary spongiosa adjacent to the osteoclasts or chondroclasts. The immunoreactions to osteopontin in the cytoplasm of hypertrophic chondrocytes were less in 56-day-old rats than in 28-day-old rats. It is shown that the alteration in mechanical loading on the mandibular condyle due to functional changes from weaning to mastication correlates with the localization of osteopontin in growing rats. Furthermore, it is suggested that osteopontin may stimulate osteoclastic resorption of calcified matrix by mediating the attachment of osteoclasts and/or chondroclasts during growth-related functional remodeling of the condyle.

Journal Article↗
PubMed2001

Effects of bisphosphonate on the remodeling of rat sagittal suture after rapid expansion.

The purpose of this study was to investigate the effects of bisphosphonate (BP), an inhibitor of bone resorption, on the remodeling of the rat sagittal suture after rapid expansion. Wistar strain male rats were divided into 4 groups and subjected to rapid mechanical expansion with an initial force of 60 g for 3 days. Immediately after the sutural expansion, the appliance was removed in 2 of the groups. In the S group, half of the animals were injected with saline solution daily for 3 days and the other half were injected daily for 7 days prior to sacrifice. In the B group, half of the animals were injected with bisphosphonate daily for 3 days and the other half were injected daily for 7 days prior to sacrifice. The remaining 2 groups underwent 7 days of mechanical retention before the appliance was removed. In the SR group, half of the animals were injected with saline solution daily for 3 days and the other half were injected daily for 7 days prior to sacrifice. In the BR group, half of the animals were injected with bisphosphonate solution daily for 3 days and the other half were injected daily for 7 days prior to sacrifice. The calvariae were fixed in 4% neutral formalin, decalcified, and embedded in paraffin. The amount of relapse and the relevant bone remodeling were evaluated in terms of a relapse ratio and the number of osteoclasts. The relapse ratio was 54.11% in the S group and 32.53% in the B group 7 days after the injection. This ratio was 25.13% in the SR group and 9.60% in the BR group. The number of osteoclasts 3 days after injection was 15.47 in the S group, which was significantly greater than the 5.26 present in the B group. This number was 7.08 in the SR group, which was significantly greater than the 1.83 in the BR group. These results demonstrate that the injection of BP after rapid expansion, if combined with mechanical retention, may produce more secure retention by inhibiting bone resorption, indicating a possibility of employing a pharmaceutical aid to decrease the skeletal relapse after mechanotherapy in clinical orthodontics.

Acid Phosphatase↗
PubMed2001

Reduction of the hypocone of the maxillary first molar and Class III malocclusion.

This study was conducted to examine the incidence of evolutionary changes of the maxillary molars in orthodontic patients and to investigate the association of this event with craniofacial growth. Among 4,892 Japanese patients treated at the orthodontic clinic of Hiroshima University Dental Hospital, 59 patients presented with a defect of the distolingual cusp of the maxillary first molar. They consisted of 52 female patients and seven male patients with a mean age of 14.7 years. Eruption of the maxillary first and second molars was delayed and the third molar was congenitally missing in all of these patients. Thirty-seven patients exhibited Class III malocclusion (Class III evolution group). The Z scores of cephalometric measurements were compared between the Class III evolution group and the Class III control group. The latter group consisted of 37 Class III subjects with no evolutionary dental anomalies and no orthodontic history. The tooth developmental score (TDS) for each age at the initial record was compared with Nolla's standard tooth developmental score (STDS) for equivalent ages using paired t-tests. The Z scores for Ptm'-A and Ar-A were significantly smaller in the Class III evolutionary group than in the Class III control group (P < .05). The TDS for the maxillary first and second molars were significantly smaller than the STDS for these molars (P < .01). The TDS for the maxillary second molar was significantly larger than the STDS for the maxillary third molar (P < .01). This study revealed that an evolution change of the maxillary molar is more common (P < .05) in female patients than in male patients, is more frequent (P < .05) in subjects with Class III malocclusion, and is related to the anteroposterior undergrowth of the maxilla.

Adaptation, Biological↗
PubMed2001

Influences of occlusal and skeletal discrepancies on biomechanical environment in the TMJ during maximum clenching: an analytic approach with the finite element method.

The purpose of this study was to investigate the influences of occlusal and skeletal discrepancies on temporomandibular joint (TMJ) stresses during maximum clenching. A three-dimensional (3-D) finite element model of the mandible including the TMJ was developed as a standard model. Furthermore, nine modified models were established; one dentoalveolar open bite model and eight skeletal open bite models with varying gonial angles or mandibular plane angles (FMAs). For the dentoalveolar open bite model, the TMJ stresses were larger than those for the standard model, although the distribution pattern was not essentially varied. In the skeletal open bite model with greater gonial angle or FMA, the TMJ stresses were significantly larger than those in the dentoalveolar open bite model. In conclusion, the TMJ stress was affected by occlusal and/or skeletal discrepancies, if coexisted in particular, indicating the association with degenerative changes of the TMJ components.

Biomechanical Phenomena↗
PubMed2001

Stress analysis in the TMJ during jaw opening by use of a three-dimensional finite element model based on magnetic resonance images.

This study was designed to investigate temporomandibular joint (TMJ) stress distribution during mouth opening using a finite element (FE) model of an individual TMJ based on magnetic resonance (MR) images. A dry skull with a silicon disk was used to test the three-dimensional reconstruction procedure, and showed enough accuracy and reproducibility in linear dimensions and disk volume for the following FE modelling for stress analysis in the TMJ. From an individual FE analysis of a normal subject, relatively high stresses were observed in the anterior and posterior regions of the disk during mouth opening, and furthermore, the superior boundary contacting with the glenoid fossa exhibited lower stresses than those on the inferior boundary facing the condyle. During transmission of stress through the disk, mechanical stress may be reduced by the stress redistribution function of the disk.

Adult↗
PubMed2001

Effects of vascular endothelial growth factor on osteoclast induction during tooth movement in mice.

UNLABELLED: For orthodontic tooth movement, remodeling of the alveolar bone is maintained by a repeated process of bone resorption and new bone formation, controlled, respectively, by osteoclasts and osteoblasts. Recently, we have found that recombinant human vascular endothelial growth factor (rhVEGF) acts as a macrophage colony-stimulating factor in osteoclast induction in osteopetrotic (op/op) mice. The purpose of this study was to investigate whether rhVEGF stimulates osteoclast differentiation during experimental tooth movement. Purified rhVEGF was injected once into the buccal gingival groove around the incisors. An experimental appliance with a helical loop was bonded onto the upper incisors, and an initial force of 1.0 g was applied for three days. The number of osteoclasts appearing in the periodontal ligament space on the pressure side of the alveolar bone was increased markedly. These results suggest that local administration of rhVEGF enhances the number of osteoclasts, and may increase the rate of orthodontic tooth movement. ABBREVIATIONS: recombinant human vascular endothelial growth factor (rhVEGF), macrophage colony-stimulating factor (M-CSF), osteopetrotic mice (op/op mice),fms-like tyrosine kinase (Flt-1), periodontal ligament (PDL), phosphate-buffered saline (PBS), tartrate-resistant acid phosphatase (TRAP), and analysis of variance (ANOVA).

Acid Phosphatase↗
PubMed2001

Analysis of histochemically and morphometrically in the anterior belly digastric muscle of osteopetrotic (op/op) mice.

The fibers of the anterior belly digastric muscle of mice, fed a granulated diet for various periods, have been studied histochemically and morphometrically. The diameters of the anterior belly digastric fibers in normal mice fed only a granulated diet were smaller than those in mice fed a solid diet. Differences in the succinate dehydrogenase (SDH) activity of muscle fibers between op/op and normal mice gradually appeared in the anterior belly digastric muscle and, by the age of 90 days, under-development of muscle fibers was observed in the mild-belly region of the anterior belly digastric muscle of op/op mice fed a granulated diet. These results indicate mechanical stress in mastication plays an important role in the development of the anterior belly digastric muscle structures.

Animals↗
PubMed2001

Proinflammatory cytokines regulate the gene expression of hyaluronic acid synthetase in cultured rabbit synovial membrane cells.

To elucidate the mechanism of accumulation and fragmentation of hyaluronic acid (HA) under inflammatory conditions, we investigated the effect of proinflammatory cytokines on hyaluronic acid synthetase (HAS) mRNA expression using cultured rabbit synovial membrane cells. HASs mRNA levels were determined by real-time PCR. HAS2 mRNA expression was maximally enhanced 3.3- and 2.8-fold after 3-hour stimulation with IL-1beta (1 ng/ml) and after 1-hour stimulation with TNF-alpha (10 ng/ml). HAS3 mRNA expression was increased by a maximum of 4.3 times after 3-hour stimulation with IL-1beta (10 ng/ml), whereas 1-hour stimulation with TNF-alpha (10 ng/ml) and IFN-gamma (10 ng/ml) induced around a 2.5-fold increase in HAS3 mRNA. Although IFN-gamma (1-100 ng/ml) alone showed little effect on HAS2 mRNA expression, the effect was synergized by combined with both IL-1beta and TNF-alpha, substantially increasing HAS2 mRNA expression. These results suggest that proinflammatory cytokines regulate the HAS expression, and consequently may contribute to the accumulation and fragmentation of HA.

Animals↗
PubMed2001

A quantitative electromyographic analysis of masticatory muscle activity in usual daily life.

OBJECTIVE: This study was designed to investigate whether a quantitative electromyographic (EMG) analysis with a special reference to the EMG amplitude at 98N bite force could reduce the influence of electrode relocation and to examine the reproducibility of masticatory muscle activity in usual daily life within individuals. SUBJECTS AND METHODS: In the first experiment, two sessions of surface EMG recording for masseter and anterior temporal muscles during tapping, and chewing gum and marshmallow were performed for 10 subjects with an interval of at least 1 week with electrode relocation. In the second experiment, two sessions of EMG recording during daytime (142 min, including mealtime) and sleep (142 min) were carried out for 10 subjects with an interval of at least 1 week. The average rectified EMG values were normalised with a special reference to the EMG amplitude induced by a 98N bite force. RESULTS: In the first experiment, high correlation coefficients and no significant differences in the mean normalised values of muscle activity were found between two sessions. Although the average rectified values showed high correlation coefficients, the mean masseter muscle activity while chewing gum was significantly different between two sessions. In addition, the variation in temporal muscle activity between two sessions while chewing gum was significantly smaller in the normalised values than in the average rectified ones. In the second experiment, less intra-individual variation in the normalised values of masticatory muscle activity between two sessions indicated the reproducibility. Normalised masticatory muscle activity showed less variation during mealtimes than during usual daytime and sleep. CONCLUSIONS: This quantitative EMG analysis could estimate the masticatory muscle activity by reducing the influences of electrode relocation, demonstrating an availability of this analysis for the evaluation of masticatory muscle activity in usual daily life.

Activities of Daily Living↗
PubMed2001

Mechanical properties of human articular disk and its influence on TMJ loading studied with the finite element method.

The present study was designed to investigate the elastic modulus of human temporomandibular joint (TMJ) disk under tension and its influences on TMJ loading. Seven human TMJ disks served as specimens. Continuous tensile stress was applied to each specimen, and the elastic moduli of human TMJ disks were calculated at 2% strain. Furthermore, using a three-dimensional finite element model of the mandible including the TMJ, changes in the TMJ stresses during clenching were evaluated in association of varying elastic moduli of the articular disk determined by the tensile tests. The elastic moduli at 2% strain varied from 27.1 to 65.2 MPa with a mean of 47.1 MPa. A significant correlation was found between the elastic moduli and age (P < 0.01). On the surface of condyle, compressive stress in the anterior area and tensile stress in the posterior area increased when the elastic moduli of the TMJ disk was varied from 25 to 65 MPa. In the TMJ disk, shear stresses in all the areas became larger with greater stiffness. In conclusion, it is shown that the elastic modulus of human TMJ disk is increased with age and that higher stiffness of the disk exerts substantial influences on mechanical loading for the TMJ structures.

Adult↗
PubMed2000

Regulation of the development of allodynia by intrathecally administered P2 purinoceptor agonists and antagonists in mice.

Effects of agonists and antagonists of P2X-purinoceptors on the regulation of the development of allodynia were examined in mice; the drugs were administered intrathecally to the spinal cord. Suramin (5, 10 microg) and pyridoxalphosphate-6-azophenyl-2', 4'-disulfonic acid (PPADS), antagonists of P2X receptors, inhibited prostaglandin (PG) E(2)-induced allodynia. PPADS did not block glutamate-induced allodynia. alpha,beta-Methylene ATP (alpha, beta-meATP), an agonist of P2X receptor, elicited allodynia. alpha, beta-me ATP-induced allodynia was blocked by co-administration of alpha,beta-meATP with PPADS, MK 801 or N(omega)-nitro-L-arginine methyl ester (L-NAME). Suramin at higher doses (20, 40 microg) induced allodynia, which was inhibited by MK 801 or L-NAME. These results suggest that ATP P2X receptors in the spinal cord are involved in the regulation of tactile allodynia. Glutamate receptor and nitric oxide systems play an important role in the development of allodynia produced by alpha,beta-meATP and suramin.

Adenosine Triphosphate↗
PubMed2000

Effects of insulin-like growth factor-I on nasopremaxillary growth under different masticatory loadings in growing mice.

It is well accepted that reduced masticatory function induced by a diet with soft physical consistency causes alterations in the craniofacial morphology in growing animals. It is assumed that these alterations are associated with reduced proliferative activity of osteoblasts on the bone surface, indicating a significant role for mechanical stimuli mediated by various local growth factors including insulin-like growth factor-I (IGF-I). Here, the effects of IGF-I on the linear growth of nasal and premaxillary bones subjected to different masticatory loadings were examined. The length of the nasal bone and the width of the premaxilla were measured. These dimensions were significantly greater in mice fed a solid diet than in mice fed a granulated diet. In animals treated with IGF-I, the nasal bone length and premaxillary width increased significantly in a subgroup receiving a solid diet, but these changes were not found in a similar group fed a granulated diet. No statistically significant differences in these dimensions were found between solid-diet mice injected with saline and granulated-diet group injected with IGF-I. It is concluded that IGF-I induces nasal and premaxillary growth, and that its effect is enhanced or accelerated by increased mechanical masticatory loading.

Analysis of Variance↗
PubMed2000

Changes in the biomechanical properties of the rat interparietal suture incident to continuous tensile force application.

This study was designed to investigate the relation between the biomechanical behaviour of rat interparietal sutures and expansion forces placed on them. Thirty-five 4-week-old rats were divided into four groups, a control group and three experimental groups subjected to mechanical expansion of the interparietal sutures with a tensile force for 15, 30 and 50 h. After expansion, the parietal bones, including the interparietal suture, were dissected as specimens for tensile tests. Under tension, the relaxed stress-strain plots in the control group could be better fitted by a power of 2.00, and the relaxed moduli were 0.64 and 4.51 MPa at the lower and the higher applied strains, respectively. An initial fall in the relaxed moduli at 15 h of expansion was followed by an increase over time. It is therefore suggested that the biomechanical behaviour of the interparietal sutures is influenced by the duration of an external force.

Animals↗
PubMed2000

Effects of tensile forces on the expression of type III collagen in rat interparietal suture.

The aim was to investigate the direct contribution of mechanically induced stress to synthesized type III collagen in the interparietal suture. Twenty 4-week-old male rats were used as experimental animals. An activated expansion spring was placed across the interparietal suture. After expansion, the parietal bones including the suture were dissected and immunostained for type I and III collagens. Also, a three-dimensional model of the interparietal suture was developed to analyze stress during expansion. The localization of type III collagen in the suture was dependent upon the duration of expansion. Although the control suture exhibited no or little reactivity for type III collagen, it was observed as early as 15 h of expansion in the cambial layers, and was distributed throughout the suture at 50 h of expansion. The time-dependent distribution of type III collagen was fully consistent with that of tensile stresses calculated by the use of a three-dimensional finite-element model. It was concluded that the increases in tensile stress are associated with the synthesis of type III collagen in the suture.

Animals↗
PubMed2000

Morphological differences in individuals with lip competence and incompetence based on electromyographic diagnosis.

The study group consisted of 19 subjects with positive overjet and overbite, and 17 subjects with skeletal open bite. Two bipolar surface electrodes were attached to the skin of the upper and lower lips. The mean integrated amplitude of the electromyographic (EMG) activity was obtained at the mandibular rest position with the lips in contact and with the lips apart. Subjects were divided into two groups based on positive or negative values of the difference in integrated EMG activity of the mentalis muscle between the two lip positions. Subjects displaying a negative value were classified as having competent lips and those displaying a positive value were classified as having incompetent lips. The EMG activity of the mentalis muscle was found to be more indicative of lip sealing as compared with the EMG activity of the depressor of the lower and the upper lips. The activities of the mentalis muscle at the mandibular rest position with the lips in contact and with the lips apart appear to offer an objective criterion for the evaluation of lip incompetence. In addition, the vertical dimension of the face, as well as the proclination of the incisors, appear to affect lower lip function.

Adult↗