Biomedical subjects

K Tanne

Publications and source records attributed to K Tanne.

At least 73 records · Page 4Linked to original sources

PubMed2000

Stress distribution in the temporomandibular joint affected by anterior disc displacement: a three-dimensional analytic approach with the finite-element method.

The purpose of this study was to investigate the influences of anterior disc displacement on TMJ loading during maximum clenching by use of finite-element analysis. Based on a young human dry skull, an analytic model of the mandible including the TMJ was developed. In addition to the standard model with normal disc-condyle relation, two models were designed to simulate various degrees of anterior disc displacement. In the standard model, compressive stresses were induced in the anterior, middle and lateral areas on the condyle and glenoid fossa, whereas tensile stresses were observed in the posterior and medial regions. In the models with anterior disc displacement, compressive stresses were recognized in all the areas of TMJ components excluding the bilaminar zone. Shear stresses in the articular disc and bilaminar zone significantly increased in most areas. In conclusion, stress distributions in the TMJ with a normal disc position was substantially different from those with anterior disc displacement, suggesting that the progress in disc displacement may have some association with the nature of stress distributions in the TMJ, in the articular disc in particular.

Bite Force↗

PubMed2000

Viscoelastic properties of the human temporomandibular joint disc in patients with internal derangement.

PURPOSE: This study investigated the viscoelastic properties of human temporomandibular joint (TMJ) discs in patients with severe internal derangement (ID). PATIENTS AND METHODS: TMJ discs obtained from 5 patients with severe TMJ internal derangement were analyzed. Normal discs derived from 2 fresh cadavers and 4 patients without ID served as the controls. The viscoelastic responses of the discs to tensile forces were evaluated by means of stress-strain analyses. RESULTS: The discs in both groups exhibited a nonlinear stress-strain relationship that was represented by a power function of the strain. However, after stress relaxation, the ID discs were likely to exhibit a linear stress-strain relationship. The instantaneous elastic moduli were almost the same in both discs, but the relaxed elastic modulus of the ID discs was significantly greater than that of the controls in lower strain range of less than 2%. CONCLUSIONS: ID discs are more rigid than normal discs. These findings suggest that the changes in viscoelastic property of the discs in patients with ID are somewhat different from those that occur with aging.

Adult↗

PubMed2000

An adult case of TMJ osteoarthrosis treated with splint therapy and the subsequent orthodontic occlusal reconstruction: adaptive change of the condyle during the treatment.

This article reports treatment for a 21-year 11-month old female patient with severe osteoarthrosis of the TMJ with a special reference to adaptive changes of the condyle during the treatment. She had severe open bite with a Class II molar relationship; she had limited mouth opening, TMJ sounds, pain, and tinnitus. Lateral tomograms showed flattening and deep erosion on the left condyle, and an MRI revealed anterior disk displacement without reduction. By manipulation and splint therapy, TMJ pain and tinnitus were eliminated, then orthodontic treatment was initiated, maintaining the splint-induced position of the condyles. After 2 years of orthodontic treatment with a multibracket appliance, an acceptable occlusion was achieved with a Class I molar relationship. On lateral tomograms after treatment, bony deformation of the left condyle disappeared and adaptive remodeling was recognized with a uniform joint space in the left TMJ. However, repositioning of the disk was not achieved. Adaptive changes or functional remodeling experienced in this patient may be due to stable occlusion, uniform joint space, and the consequent biomechanical equilibrium in the TMJ.

Adaptation, Physiological↗

PubMed2000

Masticatory muscle activity in children and adults with different facial types.

The purpose of this study was to examine the relationship between the duration of masticatory muscle activity during daytime and vertical craniofacial morphology in children and adults. Thirty children (12 boys and 18 girls) and 30 adults (20 men and 10 women) with normal anteroposterior skeletal relations, acceptable occlusions, and without any temporomandibular joint disorders, were selected as subjects. Activities of the masseter, temporal, and digastric muscles were recorded for 3 hours during daytime, excluding the periods for meals, sleep, and hard-exercise, using a portable electromyogram recording system. A lateral cephalogram was taken of each subject at the intercuspal position to divide the subjects into 3 different facial types, ie, low, average, and high angle groups. Masseter, temporal, and digastric muscle activities mainly consisted of low-amplitude bursts during daytime. Children exhibited longer duration of temporal muscle activity, whereas the masseter muscle presented longer duration of activity in adults. The activities of masseter and digastric muscles were significantly related with the vertical facial type in both children and adults, although temporal muscle activity presented no significant relationship with the craniofacial morphology. The duration of masticatory muscle activity during daytime showed a significant difference between children and adults, indicating a close association with vertical craniofacial morphology in children and adults.

Adult↗

PubMed2000

The effects of high magnitude cyclic tensile load on cartilage matrix metabolism in cultured chondrocytes.

Excessive mechanical load is thought to be responsible for the onset of osteoarthrosis (OA), but the mechanisms of cartilage destruction caused by mechanical loads remain unknown. In this study we applied a high magnitude cyclic tensile load to cultured chondrocytes using a Flexercell strain unit, which produces a change in cell morphology from a polygonal to spindle-like shape, and examined the protein level of cartilage matrixes and the gene expression of matrix metalloproteinases (MMPs), tissue inhibitors of matrix metalloproteinases (TIMPs) and proinflammatory cytokines such as IL-1beta and TNF-alpha. Toluidine blue staining, type II collagen immunostaining, and an assay of the incorporation of [35S]sulfate into proteoglycans revealed a decrease in the level of cartilage-specific matrixes in chondrocyte cultures subjected to high magnitude cyclic tensile load. PCR-Southern blot analysis showed that the high magnitude cyclic tensile load increased the mRNA level of MMP-1, MMP-3, MMP-9, IL-1beta, TNF-alpha and TIMP-1 in the cultured chondrocytes, while the mRNA level of MMP-2 and TIMP-2 was unchanged. Moreover, the induction of MMP-1, MMP-3 and MMP-9 mRNA expression was observed in the presence of cycloheximide, an inhibitor of protein synthesis. These findings suggest that excessive mechanical load directly changes the metabolism of cartilage by reducing the matrix components and causing a quantitative imbalance between MMPs and TIMPs.

Animals↗

PubMed2000

Craniofacial morphology in orthodontically treated patients of class III malocclusion with stable and unstable treatment outcomes.

The purpose of this study was to investigate morphologic features of the craniofacial skeleton in treated adolescent patients with Class III malocclusion. Fifty-six subjects were divided into 2 groups, with and without acceptable treatment outcomes, which were referred to as the stable and the unstable groups. The mean age at the initial stage was 9 years 3 months in the stable group and 9 years 4 months in the unstable group. All subjects underwent chincup therapy, with a mean duration of 3 years 9 months. On the basis of lateral cephalograms taken at 4 different stages, the means of the z scores for 20 measurements were calculated and compared between the 2 groups by means of the Student t test. Discriminant analysis was also conducted to extract key determinants to discriminate between the 2 groups. The gonial angle was significantly larger in the unstable group than in the stable group at the initial stage, and this increased over time. The mandible of the unstable group exhibited downward-and-backward rotation during early treatment and then rotated in an upward-and-forward direction after the correction of the anterior crossbite. A significant forward growth of the mandible was also found in the unstable group for the same period. Furthermore, the gonial, N-A-Pog, and ramus plane to SN plane angles were selected as the significant variables for discriminating the 2 groups with a high precision. In conclusion, it is shown that upward-and-forward rotation of the mandible, in combination with the forward growth and displacement, is highly associated with unsatisfactory treatment outcomes after pubertal growth in growing Class III patients.

Adolescent↗

PubMed1999

RGD-CAP ((beta)ig-h3) enhances the spreading of chondrocytes and fibroblasts via integrin alpha(1)beta(1).

In previous studies, RGD-CAP (collagen-associated protein containing the RGD sequence) isolated from a collagen fiber-rich fraction of pig cartilage was found to be orthologous to human (beta)ig-h3, which is synthesized by lung adenocarcinoma cells in response to transforming growth factor-beta. In the present study, we examined the effect of recombinant chick RGD-CAP on the spreading of chondrocytes and fibroblasts using RGD-CAP-coated dishes. When rabbit articular chondrocytes, chick embryonic sternal chondrocytes, rabbit peritoneal fibroblasts or human MRC5 fibroblasts were seeded on plastic dishes coated with RGD-CAP, cell spreading was enhanced compared with that on control dishes (bovine serum albumin- or beta-galactosidase-coated dishes). The effect of RGD-CAP on the cell spreading required divalent cations (Mg(2+) or Mn(2+)), and was reduced by EDTA. Monoclonal antibodies (mAbs) to the human integrin alpha(1) or beta(1) subunit, but not to the alpha(2), alpha(3), alpha(5) or beta(2) subunits, suppressed the RGD-CAP-induced spreading of human MRC5 fibroblasts. In a parallel experiment, the mAb to the alpha(5) subunit, but not the mAb to the alpha(1) subunit, suppressed fibronectin-induced spreading of these cells. These findings suggest that RGD-CAP is a novel ligand for integrin alpha(1)beta(1) that dose not bind to the RGD motif. Accordingly, an RGD-CAP fragment, which carries a deletion in the C-terminal region containing the RGD motif, was still capable of stimulating cell spreading.

Animals↗

PubMed1999

Vascular endothelial growth factor can substitute for macrophage colony-stimulating factor in the support of osteoclastic bone resorption.

We demonstrated previously that a single injection of recombinant human macrophage colony-stimulating factor (rhM-CSF) is sufficient for osteoclast recruitment and survival in osteopetrotic (op/op) mice with a deficiency in osteoclasts resulting from a mutation in M-CSF gene. In this study, we show that a single injection of recombinant human vascular endothelial growth factor (rhVEGF) can similarly induce osteoclast recruitment in op/op mice. Osteoclasts predominantly expressed VEGF receptor 1 (VEGFR-1), and activity of recombinant human placenta growth factor 1 on osteoclast recruitment was comparable to that of rhVEGF, showing that the VEGF signal is mediated through VEGFR-1. The rhM-CSF-induced osteoclasts died after injections of VEGFR-1/Fc chimeric protein, and its effect was abrogated by concomitant injections of rhM-CSF. Osteoclasts supported by rhM-CSF or endogenous VEGF showed no significant difference in the bone-resorbing activity. op/op mice undergo an age-related resolution of osteopetrosis accompanied by an increase in osteoclast number. Most of the osteoclasts disappeared after injections of anti-VEGF antibody, demonstrating that endogenously produced VEGF is responsible for the appearance of osteoclasts in the mutant mice. In addition, rhVEGF replaced rhM-CSF in the support of in vitro osteoclast differentiation. These results demonstrate that M-CSF and VEGF have overlapping functions in the support of osteoclastic bone resorption.

Animals↗

PubMed1999

Recruitment of osteoclasts in the mandibular condyle of growing osteopetrotic (op/op) mice after a single injection of macrophage colony-stimulating factor.

The purpose was to elucidate histological changes in the mandibular condyle and ramus in growing osteopetrotic (op/op) mice after a single injection of macrophage colony-stimulating factor (M-CSF). M-CSF (5 microg) was injected into 6-, 11-, 26-, 56- and 86-day-old op/op mice, and the mice were killed 4 days after the injection. In normal mice, the condyle was substantially wider than the ramus beneath it, and enlargement and ossification of the condyle occurred after weaning. These changes were not found in the uninjected and injected op/op mice, the condyles of which were occupied by hypertrophic cartilage cells, and the hypertrophic cell layer was thicker and more irregular in the arrangement of epiphyseal cell columns. In spite of the lack of bone resorption in uninjected and injected op/ op mice, ossification of the mandibular ramus occurred, but later than that of normal mouse. The number of tartrate-resistant acid phosphatase-positive cells in the injected op/op and normal mice approached a maximum at 30 days and then gradually decreased up to 90 days of age, although the numbers were substantially different for all ages. The uninjected op/op mice had no visible osteoclasts until 15 days and their number then increased significantly from 60 to 90 days of age. These results were considered due to the difference in biological responses of bony structures to M-CSF injection in the op/op mice. The influences of mechanical stimuli from masticatory functions, which are deficient in op/op mice, might also be responsible for the differences in bony architecture between the op/op and normal mice.

Animals↗

PubMed1999

Viscoelastic properties of canine temporomandibular joint disc in compressive load-relaxation.

The present study was designed to investigate the mechanical properties and load-relaxation of these discs in compression. Eight discs were used for the experiments. Compression was applied to specimens up to the specified strain, and a series of load-relaxation tests was conducted on each specimen from 0.25% strain to 2.0% strain with 0.25% intervals. The load-relaxation was monitored over a period of 2 min. The elastic moduli of the canine articular discs were 30.9 and 15.8 MPa at t = 0 and 120 sec, respectively, and the discs exhibited near-linear elastic characteristics at each time within a 2-min period. At all strains, the time-dependent load-relaxation curves showed that the load decreased markedly for the initial 30 sec, after which it levelled off after 120 sec with a steady nonzero level. This relaxation feature can be well represented by Kelvin's model. It is concluded that the canine temporomandibular joint disc can be represented as a linear viscoelastic material, and that it plays an important part as a stress absorber under compression.

Animals↗

PubMed1999

Influences of vertical occlusal discrepancies on condylar responses and craniofacial growth in growing rats.

The present study was conducted to investigate the influence of vertical occlusal discrepancies on condylar remodeling and the subsequent craniofacial growth in growing rats. Thirty 4-week-old male Wistar strain rats were used. A 1-mm-thick metal plate was bonded onto the occlusal surface of the maxillary molars to increase posterior dentoalveolar height. During the early phase of the experiment, the thickness of the proliferative and maturative/hypertrophic zones in the anterior and superior portions of the condyle was significantly smaller in the experimental group than in the controls. The number of TRAP-positive cells was significantly greater in the experimental group than in the controls. At the end of the experiment, decreased ramus height and a large gonial angle were found in the experimental group. Changes in the intra-articular environment associated with vertical occlusal discrepancies may influence condylar and craniofacial growth in growing individuals, although some adaptive response of the condyle may be induced if growth potential remains.

Acid Phosphatase↗

PubMed1999

Influence of dietary n-3 polyunsaturated fatty acid on experimental tooth movement in rats.

This study was conducted to investigate the influence of dietary n-3 polyunsaturated fatty acid on experimental tooth movement. This acid substantially reduces the production of arachidonic acid. Sixty 4-week-old male Wistar strain rats were divided into experimental and control groups. Animals in the experimental group were fed a purified diet containing 10% refined fish oil (rich in n-3 fatty acid); control animals were fed a diet containing 10% corn oil (rich in n-6 fatty acid). After 6 weeks, the maxillary first molars were moved buccally with an initial force of 20 g for periods of 0, 3, 7, or 14 days. Tooth movement in the experimental group was 80% of that seen in the controls. The number of osteoclasts on the pressure side during tooth movement was nearly 60% of that seen in controls, and the degree of bone resorption was 80%. The data suggest that a diet enriched with fish oil reduces osteoclastic activity and subsequent alveolar bone resorption that is the key to experimental tooth movement.

Alveolar Bone Loss↗

PubMed1999

Masseter muscle activity during the whole day in children and young adults.

Changes in size and shape of the craniofacial skeleton during growth may be related to the masticatory muscle function in daily life. The purpose of this study was to measure the masseter muscle activity during the whole day in children and to investigate the differences between children and young adults. Fifteen children (7.8-13.0 years of age) and 30 young adults (20.3-34.7 years of age), who had acceptable occlusions without any remarkable skeletal discrepancy or temporomandibular disorder, were used as the subjects. In both children and young adults, most high-amplitude bursts of masseter muscle appeared mainly during mealtime, whereas a substantially larger number of low-amplitude ones were widely distributed throughout the whole day. The number and total duration of bursts of masseter muscle activity during the whole day was greater in children than in young adults, although significant differences were not found between the sexes. During daytime and sleep, both the number and total duration of bursts were greater in children. During mealtime, no significant differences in the number of bursts were found between children and young adults, however, the duration of bursts tended to be longer in children. It is concluded that the masseter muscle activity during the whole day is greater in children than in young adults.

Adolescent↗

PubMed1999

Reconsideration of the TMJ condylar position during internal derangement: comparison between condylar position on tomogram and degree of disk displacement on MRI.

The objective of this study was to investigate condylar position during different degrees of disk displacement. The degree of disk displacement was evaluated on 1.5 Tesla high-field sagittal MR images of 76 joints (48 patients; mean age 19.4 years) and was classified into three grades (1 to 3). To establish condylar position, the anterior, superior and posterior joint spaces were measured on corrected tomograms. The possible relationship between condylar position, indicated by the width of joint space and successive degree of disk displacement, was compared by a one-way factorial ANOVA (p < 0.05). The anterior joint space was significantly larger in grades 1, 2, and 3 disk displacements than in grade 0 pointing to a dorsal condylar position. The posterior joint space was significantly smaller in grades 1 and 2 compared with grade 0. When the degree of the disk displacement becomes severe (i.e., grade 3 disk displacement), the posterior joint space tends to increase to a similar distance as in a normal healthy joint pointing to a more normal condylar position.

Adolescent↗

PubMed1999

Histological and histochemical quantification of root resorption incident to the application of intrusive force to rat molars.

This study was conducted to investigate the nature of root resorption resulting from intrusive forces applied to the rat lower molars, by means of histological and histochemical techniques with tartrate resistant acid phosphatase (TRAP). Thirty-eight 13-week-old Wistar strain male rats were used. Intrusive force was created by a fixed appliance which was adjusted to exert an initial force of 50 g for the duration of 1, 2, and 3 weeks. The degree of root resorption and distribution of TRAP positive cells were evaluated. On the root surface, the TRAP positive scores were low in the apical regions. Significant differences in the scores were found in the inter-radicular region of the roots between the experimental and control groups for the 2- and 3-week groups. More active resorption of bone occurred during the experimental period, as denoted by greater TRAP positive scores on the bone than on the root surface. Root resorption scores in the apical root region were larger in the 2- and 3-week groups than in the 1-week group. Significant differences in the root resorption scores were also found between the 1- and 3-week groups in the inter-radicular region, indicating that intrusive force application of a longer duration may lead to a higher frequency of root resorption. It is shown that, irrespective of the level of TRAP positive cells and root resorption scores, the degree of root resorption activity is higher in the apical root region than in the inter-radicular area. These results indicate that cellular cementum may be resorbed more easily because of its richer organic components and low mineralized structure.

Acid Phosphatase↗

PubMed1999

Congenital osteoclast deficiency in osteopetrotic (op/op) mice is improved by ovariectomy and orchiectomy.

We examined the changes in the appearance of osteoclasts in the femora of ovariectomized (OVX) or orchiectomized (ORX) op/op mice. Osteoclasts on the trabecular bone surface of the OVX or ORX op/op mice significantly increased in number seven or eight times in comparison with sham-operated op/op mice. Furthermore, TRAP-positive cells increased about four times in 100-week-old females and males, compared with sham-operated groups. These results have indicated that a sex hormone reduction due to OVX or ORX induces prominent recruitment of osteoclasts in op/op mice.

Animals↗

PubMed1999

Mechanism in inhibitory effects of vitamin K2 on osteoclastic bone resorption: in vivo study in osteopetrotic (op/op) mice.

Osteoclast deficiency in op/op mice was cured by a single injection of 5 micrograms recombinant human macrophage colony-stimulating factor (M-CSF). On d 5, the osteoclast number reached a maximum value. By d 15, the osteoclast number had decreased to about 70% of the maximum level. Moreover, by d 20, the osteoclast number had decreased to about 30% of its maximum level. On d 5, the osteoclast number of vitamin K2 12 h previously had decreased to about 30% of the M-CSF-only injected mice. Moreover, on d 5, the osteoclast number of the mice receiving a single injection of vitamin K2 24 h previously had decreased to about 15% that of mice injected only with M-CSF. These results indicate that vitamin K2 inhibits in vivo osteoclast formation. On d 20, the osteoclast number of the mice injected with a single dose of vitamin K2 12 or 24 h previously had decreased to 0% compared with those receiving only M-CSF. The present results suggest that the vitamin K2 "causes cell death" to mature osteoclasts and inhibits in vivo osteoclast formation.

Animals↗

PubMed1998

Relationship between masticatory muscle activity and vertical craniofacial morphology.

The purpose of this study was to investigate the relationship between masticatory muscle activity during the day and vertical craniofacial morphology. The sample comprised 30 subjects (20 males and 10 females, age range 15 to 28 years, mean 24 +/- 3.2 years) who had normal anteroposterior skeletal relationships and complete or nearly complete dentition without serious malocclusion or temporomandibular dysfunction. Using a portable electromyographic recording system, activities of the masseter, temporal, and digastric muscles were recorded for 3 hours during the day, excluding time spent eating, sleeping and exercising. A lateral cephalogram was taken of each subject with the teeth in occlusion. Activities of the masseter, temporal, and digastric muscles consisted mainly of low-amplitude bursts. The duration of digastric muscle activity was greater than that of either the masseter or temporal muscles. Masseter and digastric muscle activity was positively correlated. The activities of the masseter, temporal, and digastric muscles during the day consist of low-amplitude bursts and may be related to vertical craniofacial morphology.

Adolescent↗