日本人skeleatl I, skeletal III症例の歯列弓と顎顔面頭蓋における形態学的関係に関する研究

Available studies about differences among races, related to prevalence of malocclusion or morphology of head and dental arches, suggest a hypothesis that the high prevalence of skeletal Class III malocclusion in Asian ancestry populations could be correlated with a tendency toward a brachycephalic head form and larger arches widths. The purpose of the present study was to evaluate anteroposterior relationship of upper and lower jaws associated to form of dental arches, maxilla, mandible, face and head. Materials in this research consisted of pretreatment lateral and posteroanterior cephalometric radiographs and orthodontic models of Japanese females with skeletal Class I and Class III. Strong correlations between head form and jaws anteroposterior relationship could not be found. However, results indicated that skeletal Class III have statistically significant smaller length of maxilla and greater length of mandible, than the skeletal Class I group. Moreover, basal arch length and width of mandible were significantly bigger in skeletal Class III group. These results suggest that skeletal Class III, at least in this sample, might be associated to local malformation factors

Analysis of Pretreatment Factors Associated with Stability in Early Class III Treatment

BACKGROUND: The purpose of this study was to identify pretreatment factors associated with the stability of early class III treatment, since most orthodontists start the treatment with their uncertain hypotheses and/or predictions. Subjects consisted of 75 patients with a class III skeletal relationship (ANB \u3c 2° and overjet \u3c 0 mm) who had been consecutively treated with rapid maxillary expansion and facemask and followed until their second phase treatment. The patients were divided into two groups according to whether they showed relapse in follow-up. The stable group maintained their positive overjet (n = 55), and the unstable group experienced relapse with a zero or negative overjet (n = 20). Two general, three dental, and 13 cephalometric pretreatment factors were investigated to determine which factors were associated with stability. RESULTS: Sex, pretreatment age, and anteroposterior functional shift, which were hypothesized as associated factors, were not related to the stability of early class III treatment. Significant differences were detected between the two groups in the horizontal distance between the maxillary and mandibular molars in centric relation. Cephalometric variables, such as the mandibular length (Ar-Me), Wits appraisal, SN to ramus plane angle (SN-Rm), gonial angle, incisor mandibular plane angle (IMPA), and Frankfort plane to mandibular incisor angle (FMIA) showed significant differences between the groups. The horizontal distance was the most influential factor by logistic regression analysis. CONCLUSIONS: Hypothesis (related to sex, age, functional shift) were rejected. Several cephalometric factors related to the mandible were associated with stability. The horizontal distance between the maxillary and mandibular molars in centric relation was the best predictor of early class III treatment relapse

Selective disappearance of medial back muscles in a case of myotonic dystrophy type 1

Here, we report a unique case of late-onset myotonic dystrophy type 1 in a 64-year-old woman, with selective disappearance of the medial lower back muscles. We compared the clinical features of this patient with those of a cohort of 29 patients with myotonic dystrophy type 1 to clarify the correlation between clinical features and lower back muscle atrophy. After classification into three subgroups according to muscle atrophy pattern, medial muscle atrophy was present in 17.2% of the patients. Affected patients were older at onset than non-affected patients, and limb muscle power and respiratory function decreased with atrophy progression

Thread shape, cortical bone thickness, and magnitude and distribution of stress caused by the loading of orthodontic miniscrews : finite element analysis

Cortical bone thickness is assumed to be a major factor regulating miniscrew stability. We investigated stress distribution in two miniscrews with different thread shapes (type A and B) and in cortical bone of three different thicknesses using three-dimensional (3D) finite element (FE) models. More specifically, 3D FE models of two different miniscrews were created and placed obliquely or vertically into a cylindrical bone model representing different cortical bone thicknesses. When force was applied to the miniscrew, the stress distribution on the screw surface and in the peri-implant bone was assessed using FE methodology. Miniscrew safety was evaluated using a modified Soderberg safety factor. Screw head displacement increased with a decrease in cortical bone thickness, irrespective of screw type. The smallest minimum principal stresses on the screw surfaces remained constant in type A miniscrews on changes in cortical bone thickness. Minimum principal stresses also appeared on the cortical bone surface. Lower absolute values of minimum principal stresses were seen in type A miniscrews when placed vertically and with upward traction in obliquely placed type B miniscrews. Both miniscrews had acceptable safety factor values. Taken together, orthodontists should select and use the suitable miniscrew for each patient in consideration of bone properties

Decreased alveolar bone turnover is related to the occurrence of root resorption during experimental tooth movement in dogs

Objective:  To investigate the relationship between root resorption (RR) and bone turnover in two different types of tooth movement in dogs. Materials and Methods:  A total of 16 dogs in two different groups were used. Tooth movement of dog premolars resulted from approximately 200 g of force. Histomorphometric analysis of premolar roots was assessed after 4 and 12 weeks of tooth movement by comparing nonresorptive to resorptive surfaces. Results:  Histomorphometric analysis indicated a significant decrease in the bone formation rate in the root resorptive areas, which resulted in decreased bone volume after 12 weeks. The threshold to detect RR in periapical radiographs was about 1.0 mm2. Conclusions:  A sustained mechanical load, due to the prolonged stress and strain of continuous mechanics, induces elevated bone metabolic activity, such as the bone turnover (remodeling) and change in bone volume (modeling). Therefore, our data support the hypothesis that increased RR is related to decreased bone formation (turnover) in high stress areas exposed to prolonged orthodontic tooth movement

Clinical and Pathological Improvement in Stroke-Prone Spontaneous Hypertensive Rats Related to the Pleiotropic Effect of Cilostazol

Background and Purpose-Cerebral infarction is a major cause of death or decreasing activities of daily living. This study aimed to investigate the efficacy of commonly used antiplatelet drugs on stroke and motor and cognitive functions in relation to oxidative stress markers and insulin-like growth factor 1 receptor (IGF-1R). Methods-Stroke-prone spontaneously hypertensive rats were treated with vehicle, aspirin, clopidogrel, and cilostazol from 8 to 10 weeks of age. Physiological parameters, regional cerebral blood flow, and serum lipids were examined. Motor and cognitive functions were evaluated weekly by the Rotorod and water maze task. Spontaneous infarct volume, oxidative stress markers for lipid, protein, and DNA at the ischemic boundary zone of spontaneous infarction, and the IGF-1R-positive cell ratio in the hippocampus were immunohistochemically examined in brain sections. IGF-1R beta expression in the hippocampus was assessed by Western blotting. Results-The antiplatelet drugs, cilostazol and clopidogrel, reduced the spontaneous infarct volume more than aspirin. Only cilostazol improved motor and cognitive functions with a significant increase (P<0.05) in the memory-related IGF-1R-positive ratio and IGF-1R beta expression in the hippocampus. Cilostazol reduced the 4 oxidative stress markers in affected neurons in stroke-prone spontaneously hypertensive rats regardless of blood pressure, regional cerebral blood flow, or serum lipid levels. Conclusions-The present results suggest that a possible pleiotropic effect of cilostazol resulted in the reduction of spontaneous infarct volume and preservation of motor and spatial cognitive functions. The increase of IGF-1R-positive cells in the hippocampal CA1 region could partly explain the preservation of spatial cognitive function in stroke-prone spontaneously hypertensive rats

Reducing Hemorrhagic Complication by Dabigatran Via Neurovascular Protection After Recanalization With Tissue Plasminogen Activator in Ischemic Stroke of Rat

This study assesses the risks and benefits of tissue plasminogen activator (tPA) treatment under oral anticoagulation with dabigatran compared with warfarin or vehicle control in transient middle cerebral artery occlusion (tMCAO). After pretreatment with warfarin (0.2 mg/kg/day), dabigatran (20 mg/kg/day), or vehicle (0.5% carboxymethyl cellulose sodium salt) for 7 days, tMCAO was induced for 120 min, followed by reperfusion and tPA (10 mg/kg/10 ml). Clinical parameters, including cerebral infarction volume, hemorrhagic volume, and blood coagulation, were examined. At 24 hr after reperfusion, markers for the neurovascular unit at the peri-ischemic lesion were immunohistochemically examined in brain sections, and MMP-9 activity was measured by zymography. Paraparesis and intracerebral hemorrhage volume were significantly improved in the dabigatran-pretreated group compared with the warfarin-pretreated group. A marked dissociation between astrocyte foot processes and the basal lamina or pericyte was observed in the warfarin-pretreated group, which was greatly improved in the dabigatran-pretreated group. Furthermore, a remarkable activation of MMP-9 in the ipsilateral warfarin-pretreated rat brain was greatly reduced in dabigatran-pretreated rats. The present study reveals that the mechanism of intracerebral hemorrhage with warfarin-pretreatment plus tPA in ischemic stroke rats is the dissociation of the neurovascular unit, including the pericyte. Neurovascular protection by dabigatran, which was first shown in this study, could partially explain the reduction in hemorrhagic complication by dabigatran reported from clinical study

Spin correlation and relaxational dynamics in molecular-based single-chain magnets

We report the combined measurements of the dc susceptibility X0, the ac susceptibility X, and the NMR relaxation rate T for the molecular-based heterometallic single-chain magnet [Mn(saltmen)]2[Ni(pao)2(py)2](PF6)2. At low temperatures, this system is well described by a one-dimensional array of effective spin S=3 chains comprising the MnIII-NiII-MnIII trimers and treated as the S=3 Ising chain with the single-ion term (Blume-Capel model). Using the exact solution of the model and based on the picture that the random motion of the local domain walls dominates the low-temperature spin dynamics, we succeeded in reproducing the experimental results of the dc susceptibility X0, the ac susceptibility X, and the 19F-NMR relaxation rate T in a consistent manner