Biomedical subjects

K Tanne

Publications and source records attributed to K Tanne.

At least 91 records · Page 5Linked to original sources

PubMed1998

An evaluation of the biomechanical response of the tooth and periodontium to orthodontic forces in adolescent and adult subjects.

This study was designed to quantify the magnitude of tooth mobility in adolescents and adults, and to investigate the differences in the biomechanical response of tooth and periodontium to orthodontic forces. The initial displacement of the maxillary central incisor was measured in 50 adolescent and fifty adult patients and the biomechanical properties of the periodontium were examined using the finite element method (FEM) and supporting experimental data. The magnitude of tooth mobility was significantly greater in the adolescent group than in the adult group. By integrating the differences in tooth mobility in both subject groups with analytical tooth displacements, the Young's modulus of the periodontal ligament (PDL) was demonstrated to be greater in the adults than in the adolescent subjects. The differing biomechanical properties of the PDL in adults were demonstrated to result in almost equivalent or somewhat increased stress levels in the PDL in adult subjects. It is suggested that this might produce a reduction in the biological response of the PDL and thus lead to a delay in tooth movement in adults.

Adolescent↗

PubMed1998

Midpalatal suture of osteopetrotic (op/op) mice exhibits immature fusion.

The midpalatal suture was observed histologically in both toothless osteopetrotic (op/op) and normal (control) mice. The normal mice had a mature sutural structure, which consists of a well-developed cartilage cell zone and palatal bone. In contrast, the thickness of the cartilage cell zone was substantially greater in the op/op mice than that in the controls. Moreover, the cartilage cells in the op/op mice were frequently found in the palatal bone as well as in the sutural space, exhibiting an imperfect fusion. It seems that immature fusion at the sutural interface in the op/op mice is related to a decrease in biting or masticatory force accompanied by the failure of tooth eruption in addition to an essential defect in osteoclast differentiation, which is a congenital symptom in op/op mice.

Animals↗

PubMed1998

Suspension "hypokinesia/hypodynamia" may decrease bone mass by stimulating osteoclast production in ovariectomized mice.

This study was conducted to examine, in detail, the histological changes in the femurs of suspended ovariectomized (OVX) mice to assess the role of mechanical stress on bone remodeling. Suspended-OVX, suspended-sham-ope, nonsuspended-OVX, and nonsuspended-sham-operated mice underwent operations 8 weeks after birth. Immediately after operation, hypokinesia/hypodynamia was created by a suspension harness for one week. Five specimens in each group were sacrificed 9 weeks after birth. The trabecular bone of the femurs in the suspended-OVX mice was removed and replaced extensively by bone marrow. The number of tartrate-resistant acid phosphatase (TRAP)-positive cells was larger in the suspended-OVX mice than in the remaining three groups. No significant differences in the number of TRAP positive cells were found between the suspended-sham-ope, nonsuspended-OVX and nonsuspended-sham-ope mice. The femurs of the OVX mouse with suspension "hypokinesia/hypodynamia" thus exhibits extensive trabecular bone loss in association with an increase of osteoclasts.

Acid Phosphatase↗

PubMed1997

Enhancement of cartilage matrix protein synthesis in arthritic cartilage.

OBJECTIVE: To investigate whether the synthesis of cartilage matrix protein (CMP) is enhanced in arthritic cartilage. METHODS: The content of CMP in human and pig cartilage was determined by immunoblotting, and CMP-producing chondrocytes in osteoarthritic (OA) and rheumatoid arthritic (RA) joints were immunostained. RESULTS: CMP was undetectable in the condylar cartilage and disc of pigs, whereas it was abundant in the rib and tracheal cartilage of the same animals. By immunohistochemical analysis, CMP was localized in only a few chondrocytes (5%) in normal human joints, whereas numerous chondrocytes (>60%) were immunostained in RA joints. The number of CMP-producing cells was also increased in OA cartilage (>40%). Immunoblotting analyses confirmed that the CMP content in the cartilage from OA and RA patients was much higher than that in normal cartilage. CONCLUSION: These findings demonstrate that articular chondrocytes can synthesize CMP, although it is suppressed under physiologic conditions. The results also suggest that articular chondrocytes express CMP in response to arthritic stimuli.

Adult↗

PubMed1997

Influences of nasal respiratory obstruction on craniofacial growth in young Macaca fuscata monkeys.

This study was conducted to investigate the influences of artificial nasal respiratory obstruction on craniofacial growth in young Macaca fuscata monkeys. Eleven monkeys were used; seven monkeys served as the experimental animals and the remaining four as the control animals. Further, the experimental animals were divided into light and heavy obstruction groups. Nasal respiratory obstruction was created by injecting dental impression material into the nasopharyngeal region. Nasal respiratory function was evaluated in terms of nasal airway resistance. Craniofacial structure in the experimental monkeys was compared with the control animals by means of cephalometric analysis. Nasopharyngeal respiratory obstruction was associated with downward and backward rotation of the mandible, upward and backward growth of the condyle, divergent gonial angle, anterior open bite, and spaced dental arch in the lower anterior region. These changes were significantly greater in the experimental monkeys with heavy respiratory obstruction. The current findings support the hypothesis that nasal obstruction existing before and during pubertal growth may result in permanent craniofacial deformities pertinent to skeletal open bite.

Airway Resistance↗

PubMed1997

Influences of aging changes in proliferative rate of PDL cells during experimental tooth movement in rats.

This study was designed to investigate the influences of aging changes in the proliferative activity of PDL cells during experimental tooth movement in rats. Young (6-week-old) and adult (14-week-old) Wistar strain rats were used as experimental animals. Light (10 g) or heavy forces (40 g) were applied to the maxillary first molars for periods of 1, 3, 7, or 14 days. Proliferative activity of the PDL cells was evaluated immunohistochemically in terms of the ratio of the number of labeled cells to the total number of PDL cells (labeling index) or the number of labeled cells. In the controls, cellular activity was significantly greater in the young than in the adult group (P < 0.05). Significant differences in the proliferative activity between young and adult groups were found in the tension and pressure areas during early stage of tooth movement (P < 0.05), which indicated a delay of biologic responses to orthodontic stimuli in adult rats. It is shown that aging changes substantially influence proliferative activity of the PDL cells and subsequent tooth movement during the initial phase in particular.

Aging↗

PubMed1997

Diagnostic accuracy of sagittal condylar movement patterns for identifying internal derangement of the temporomandibular joint.

The aim of this study was to compare sagittal condylar movement patterns (SCMP, Axiograph) and high-field (1.5 T) magnetic resonance imaging (MRI) findings of the temporomandibular disorders. One hundred forty-one patients with TMD signs and/or symptoms were selected for this study. SCMP was categorized into six patterns: normal, figure-eight (early/intermediate/late), limited, and other irregularities. The MRI findings of TMJ internal derangement were defined as one of five stages according to Wilkes criteria and then compared to the SCMP findings. Among normal SCMP, MRI revealed disc displacement in 27%. Sixty-three percent of figure-eight SCMP were regarded as stage I or II with reducible disc displacement. The sensitivity and specificity of SCMP for detecting TMJ internal derangement were 0.79 and 0.62, respectively. The point of deflection in figure-eight SCMP and the degree of disc displacement were not significantly related. However, a significant relationship was observed between the point of deflection in figure-eight SCMP and any type of disc deformation (chi-square = 9.80, P = .002). Thus, SCMP is not yet accurate enough for diagnosing a TMJ condition, especially in the case of chronic and/or adaptive internal derangement.

Adolescent↗

PubMed1996

Masseter muscle activity during the whole day in young adults.

This study was conducted to evaluate the biting function during the entire day in young adults by measuring the masseter muscle activity with a 24-hour electromyography (EMG) system. With this system, the masseter muscle activity for 24 hours was recorded in 20 male and 10 female young adult subjects with acceptable occlusion. For the male subjects, means of the number and total duration of bursts over level 2, which is one-fourth of the maximum discharge voltage during maximum clenching, were 1938 times and 357 seconds. For the female subjects, the values were 2356 times and 419 seconds. A large percentage of such high amplitude bursts as level 3 or 4 was observed during meals in both groups. These results indicated that most of the strong bursts of the masseter muscle appeared only during meals and a number of low amplitude bursts were observed during the entire day, although masseter muscle activity during the entire day in young adults was less than expected. It is anticipated that the nature of masticatory muscle activity revealed in this study might provide valuable information about the association between the biting function and the craniofacial structure or malocclusion.

Activity Cycles↗

PubMed1996

Stress distribution in the temporomandibular joint produced by orthopedic chincup forces applied in varying directions: a three-dimensional analytic approach with the finite element method.

Stress distribution in the temporomandibular joint (TMJ) during chincup therapy was investigated by means of a three-dimensional finite element model of the mandible, including the TMJ. An orthopedic chincup force of 400 gf (3.92 N) was applied at the pogonion of the mandible in the directions ranging from -50 degrees to 40 degrees, relative to the line connecting the pogonion and condyle. Compressive stresses, widely distributed on the condyle and glenoid fossa and in the articular disk, were larger in the posterior area than in the anterior and middle regions, when the force direction was from -50 degrees to 0 degree, whereas the forces applied in the remaining directions produced relatively uniform stress distributions. An interesting finding was that tensile stresses were induced in the anterior region of the articular disk, irrespective of force direction, although the remaining areas experienced compressive stresses. It is shown that changes in stresses in the TMJ are highly pertinent to the direction of chincup forces. When the directional angle was around -50 degrees, the variation in stresses in the TMJ was greatest. As the angle was changed to 30 degrees or 40 degrees, the stresses approached a certain level of compressive stress, which indicated the force direction as an optimal application of orothopedic chincup force in terms of biomechanically balanced stress distribution for the TMJ components.

Chin↗

PubMed1996

Biologic responses of the pulp to single-tooth dento-osseous osteotomy.

OBJECTIVE: This study was conducted to investigate biologic responses of the pulp to single-tooth dento-osseous osteotomy and to explore an appropriate level of transverse bone resection for maintaining biologic activity of the pulp in monkeys. STUDY DESIGN: The levels of transverse bone resection were designed at approximately 10 mm (10 mm group) and 5 mm (5 mm group) above the apices. Histologic and histomorphometric changes were evaluated microscopically, and changes in blood flow in the pulp were also measured in terms of vascular responses to a vasoconstrictor (noradrenaline, NA). RESULTS: Vacuolar degeneration in the pulp chamber associated with less number of the pulp cells were more prominent in the 5 mm group, and the response of blood flow to NA was maintained better in the 10-mm group. CONCLUSION: It is shown in this 8-week experiment that biologic activity of the pulp is much better preserved in the 10-mm group than in the 5-mm group, whereas the pulpal response may become similar if observed for a longer period.

Alveolar Process↗

PubMed1996

Association between the direction of orthopedic headgear force and sutural responses in the nasomaxillary complex.

This study was designed to investigate biomechanical responses of the sutures in the nasomaxillary complex to orthopedic headgear forces applied in various directions. A three-dimensional analytic model of the craniofacial complex was used for finite element analysis. A posteriorly-directed force of 1.0 Kgf was applied to the maxillary first molars in 30 degrees inferior, parallel, and 30 degrees, 52.4 degrees and 60 degrees superior directions to the functional occlusal plane. Mean principal and shear stresses were evaluated at the sphenozygomatic, temporozygomatic, sphenomaxillary, frontomaxillary and frontozygomatic sutures and lamina cribrosa. As the force direction passed closer to the center of resistance (CRe) of the complex (52.4 degrees superior direction). normal stresses approached a certain level of uniform compressive stress (-2.5 gf/mm2) with gradual decrease in shear stresses, whereas variation in these stresses produced by the forces applied in other horizontal and inferior directions was greater. It is shown that stresses in the nasomaxillary sutures are varied by the direction of headgear force. Directing the line of force closer the CRe may produce the most optimal sutural modification effective for controlling forward and downward maxillary growth.

Biomechanical Phenomena↗

PubMed1996

Changes in masseter muscle activity during orthodontic treatment evaluated by a 24-hour EMG system.

This study was conducted to investigate changes in masseter muscle activity during orthodontic treatment. Data was collected using a 24-hour electromyogram (EMG) system. Bursts of masseter muscle activity were counted over 24-hour periods approximately weekly before, during, and after an 18-month period of active orthodontic treatment. The patient, a 25-year-old male, was treated with a multibracket appliance. The number of bursts decreased substantially during the initial leveling period when the archwires were adjusted and then recovered to near the original preactivation level. No remarkable changes in masseter muscle activity were recorded during the latter half of treatment, although masseter muscle activity fell again when the appliance was removed. Six months after the end of treatment, relatively stable masseter muscle activity-similar to that recorded before treatment-was maintained. These changes in masseter muscle activity during orthodontic treatment were probably due to discomfort or pain or to changes in the occlusal relationship between the maxillary and mandibular dentitions produced by tooth movement or by the orthodontic appliance itself.

Adult↗

PubMed1996

Biologic responses of autogenous bone and beta-tricalcium phosphate ceramics transplanted into bone defects to orthodontic forces.

This study was conducted to evaluate biologic responses of autogenous bone (particulate marrow and cancellous bone; PMCB) and beta-tricalcium phosphate ceramics (TCPC) to orthodontic stimuli. Nine dogs served as the experimental animals; three dogs underwent orthodontic tooth movement after grafting, three dogs received PMCB grafting without tooth movement, and three dogs received TCPC grafting without tooth movement. Immediately after extraction of the upper second and/or third incisors, the maxillary alveolar bone was resected bilaterally. Autogenous PMCB obtained from the iliac bone and TCPC were transplanted into each bone defect. Experimental tooth movement was initiated 2 to 4 weeks after the grafting and continued for 9 to 15 weeks. Sectional archwires with open-coll springs were used for distal movement of the upper first incisors into the extraction sites. Oxytetracycline and calcein were employed as bone markers. Sections of grafted areas including the teeth were prepared for light and fluorescence microscopy. The results revealed that both autogenous bone and TCPC presented similar adaptive changes to the original alveolar bone without any external stimuli. TCPC exhibited more prominent biodegradative responses to orthodontic force in association with new cementum formation. Root resorption was also less in the TCPC area than in the PMCB region. It is shown that TCPC is biodegradative in nature and adaptive for remodeling during orthodontic tooth movement. This finding indicates that TCPC may be a better biocompatible alternative to autogenous bone transplanted into bone defects subjected to orthodontic tooth movement.

Adaptation, Physiological↗

PubMed1995

Biomechanical behavior of the periodontium before and after orthodontic tooth movement.

This study was designed to investigate the biomechanical behavior of the periodontium including the periodontal ligament (PDL) in terms of tooth mobility. Tooth mobility was measured in the canines of 10 adolescent patients before and after distal movement. Distal movement of the canines was carried out by use of a calibrated sectional archwire exerting an initial retraction force of 200 g. Tooth mobility was measured immediately before and after canine retraction by use of a noncontact displacement sensor when varying distal forces of 0 to 500 g were applied to the mesial of the canine. Before tooth movement, tooth mobility exhibited a substantial increase in loading with forces ranging from 50 to 150 g. The rate of increase gradually decreased up to 500 g. A nonlinear change in tooth mobility was similarly observed at the end of tooth movement or 24 days after the initiation of movement. Tooth mobility, however, was significantly greater when forces above 200 g were loaded. The periodontal tissues--the PDL and alveolar bone in particular--become more flexible at the end of tooth movement, indicating reduced support by the periodontal tissues. These findings suggest that the elastic nature of the PDL and alveolar bone may decrease substantially at the end of tooth movement.

Adolescent↗

PubMed1995

Location of the centre of resistance for the nasomaxillary complex studied in a three-dimensional finite element model.

The purpose of this study was to investigate the location of the centre of resistance (CRe) for the nasomaxillary complex by the use of finite element analysis. A three-dimensional finite element model of the craniofacial complex, consisting of 2918 nodes and 1776 elements, was used for displacement analyses. Anteriorly and inferiorly directed forces of 9.8 N were applied at five different levels, parallel and perpendicular to the functional occlusal plane, respectively. For each loading condition, horizontal and vertical displacements of eight anatomic points in the complex and on the maxillary dentition were analysed. The complex exhibited an almost translatory displacement of approximately 1.0 microns in the forward direction when the horizontal force was applied at a point on the horizontal plane, passing through the superior ridge of the pterygomaxillary fissure, whereas the complex experienced clockwise or counter clockwise rotation when the forces were applied at the remaining levels. Furthermore, the downward forces produced anteriorly upward, or posteriorly upward rotation. However, the force applied at a point on the vertical plane passing through the posterior wall of the pterygomaxillary fissure, produced almost equal displacements of approximately 6.0 microns in an inferior direction for all the anatomic points. It is suggested that CRe of the nasomaxillary complex is located on the posterosuperior ridge of the pterygomaxillary fissure, registered on the median sagittal plane.

Biomechanical Phenomena↗

PubMed1995

Stress distributions in the TMJ during clenching in patients with vertical discrepancies of the craniofacial complex.

This study was designed to investigate stresses in the TMJ during clenching in patients with skeletal discrepancies in the vertical direction. A three-dimensional model of the mandible including the TMJ was used for finite element analysis for the stresses. The model, referred to as a standard model, consists of 2,088 nodes and 1,105 solid elements, comprising the cortical and cancellous bones, articular disc and cartilage layer, and periodontal ligament. The standard model was modified by varying the gonial and mandibular plane angles to simulate vertical discrepancies between the maxilla and mandible observed in open and deep bites. Stresses were analyzed on the surfaces of the condyle, the glenoid fossa, and the articular disc, and the values were compared to those found with the standard model. Stresses increased substantially for the condyle, the glenoid fossa, and the articular disc with greater gonial and mandibular plane angles, and those changes were more obvious in association with the divergent mandibular plane. Thus, the nature of stress distributions in the TMJ was substantially affected by vertical discrepancies of the craniofacial skeleton. It is also suggested that these changes in stresses produce a lack of biomechanical equilibrium in the TMJ, which may have some association with temporomandibular disorders.

Cartilage, Articular↗

PubMed1995

[Morphology of the mandibular condyle in osteopetrotic (op/op) mouse].

Osteopetrosis is an inherited metabolic disease which produces an excessive accumulation of bone caused by deficiency of osteoclasts. It is characterized by systemic bone sclerosis, cranial deformation and failure of tooth eruption due to defective bone resorption. In this study, morphological change of the mandible was observed in growing osteopetrotic (op/op) mutant mice. Deformation of the condylar process, non-ossification of the condyle head and underdevelopment of the lateral pterygoid muscle were observed in the mutant mice. Although these phenomena were brought about by failure of the bone remodeling, it was simultaneously suggested that the ossification of the condyle head concerned with the mastication.

Animals↗

PubMed1994

A three-dimensional finite element model of the mandible including the TMJ and its application to stress analysis in the TMJ during clenching.

The purpose of this study was to develop a three-dimensional finite element model of the mandible including the temporomandibular joint (TMJ) and further to investigate stress distributions in the TMJ during clenching. The model consisted of 2088 nodes and 1105 elements, comprising cortical and cancellous bones, articular disc, articular cartilage layer and periodontal ligament. For loading condition, a resultant force of 500 N derived from the cross-sectional areas of the muscles was applied to the model. Compressive stresses were induced in the anterior, middle and lateral areas of the TMJ during clenching, whereas the tensile stresses were induced in the posterior and medial areas. The mean principal stresses on the surface of condyle were -1.642, -0.543, 0.664, -1.017, 0.521 MPa in the anterior, middle, posterior, lateral and medial areas, respectively. The mean stresses on the surface of glenoid fossa were approximately 1/5 to 4/5 those on the surface of condyle, although the patterns of stress distributions were almost similar. In both the articular disc and cartilage layer, the stress distributions were very approximate in qualitative and quantitative aspects. Thus, it is shown that stresses during clenching vary substantially in different structures and areas of the TMJ and that the stresses are reduced by the articular disc and cartilage layer in comparison with actual biting forces exerted by the masticatory muscles, if anatomic relation between various TMJ components is well maintained.

Biomechanical Phenomena↗