To study long-term degradation of polycarbonate (PC) and the formation and the release of bisphenol A (BPA) in vivo and in vitro, PC brackets placed in the oral cavity for 18-40 months as well as bracket, denture plate, and temporary crown placed in water at 37°C for 34 months were examined for the changes of BPA content and molecular weight in PC using high performance liquid chromatography and size exclusion chromatography. BPA release in vitro was also monitored. The BPA content and molecular weight for the brackets in vivo showed a tendency to increase from 38-60 μg/g to 324- 697 μg/g and to decrease from 49 x 10³-54 x 10³ to 43 x 10³-45 x 10³ during 18-40 months, respectively. The content and total release of BPA in vitro after 34 months were 472 and 37.4 μg/g for bracket, 130 and 2.2 μg/g for denture plate, and 50 and 2.8 μg/g for temporary crown, respectively. BPA appeared to be released more in saliva than that expected from the in vitro data. Additives contained in the PC materials were suggested to influence the formation of BPA.

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We previously reported a mouse model for scleroderma by repeated local injections of bleomycin. In this study, we investigated the level of transforming growth factor-β1 (TGF-β1) in various mice strains, in order to determine whether the expression of TGF-β1 correlates with the susceptibility to bleomycin-induced scleroderma. Histological examination revealed prominent dermal sclerosis with increased collagen deposition in the bleomycin-treated skin in B10.A and C3H/HeJ strains as compared with BALB/c, C57BL/6J and DBA/2 strains. Collagen contents in the skin were also increased in B10.A and C3H/HeJ strains. Analysis of skin lesions from B10.A and C3H/HeJ exhibited the increased mRNA expression and protein synthesis of TGF-β1. TGF-β1 concentrations in culture supernatants of skin fibroblasts and spleen macrophages were significantly increased by bleomycin stimulation in B10.A and C3H/HeJ strains, and TGF-β1 gene expression in fibroblasts derived from B10.A and C3H/HeJ strains was significantly increased by bleomycin stimulation. Thus we conclude that C3H/HeJ and B10.A mice are susceptible to bleomycin-induced scleroderma, which may be, in part, due to increased TGF-β1 gene expression and protein production.

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The purpose of the present study was to measure tongue pressure with the aim of characterizing the pattern of linguopalatal contact during articulating glossal sounds in normal subjects and glossectomy patients. Tongue pressures against the palate were evaluated in 13 normal subjects and 5 glossectomy patients by using three parameters: the duration from the onset of linguopalatal contact to the time of maximum pressure, the maximum pressure, and anterior posterior ratio of the maximum pressure. Three glossal sounds, [ti], [tʃi], and [ʃi], which have tendency of mishearing in glossectomy patients, were selected for test sounds. A unique characteristic was demonstrated in normal subjects. The score of the maximum pressure showed an apparent order among the three sounds, while the durations revealed the opposite order. Anterior posterior ratio of the maximum pressure also showed some relationship among three sounds. In glossectomy patients, these characters were not found. The loss of tongue volume or deterioration of tongue mobility causes these results.

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Longitudinal dento-skeletal changes in unilateral cleft lip and palate (UCLP) patients following maxillary distraction osteogenesis using the rigid external distraction device (RED) were analyzed. Twelve Japanese non-syndromic UCLP patients who underwent maxillary distraction at the mean age of 16.4 years were used as subjects. Serial sets of lateral cephalograms, taken at 4 stages: 1) before osteotomy, 2) immediately after distraction, 3) 6 months and 4) 12 months post-osteotomy, were analyzed. Statistical analyses, including a paired t test, Pearson correlation analysis and stepwise linear regression analysis, were performed to distill characteristic dento-skeletal changes. In accordance with maxillary advancement, significant amounts of up-forward movement of the nasal bone, mandibular rotation and maxillary dental changes were observed. Maxillary dental changes were significantly related to the amount of mandibular rotation and force system of maxillary traction. Significant dento-skeletal relapse was found to occur during the 0-to-6-month follow-up period, but not in the 6-to-12-month follow-up period. Maxillary relapse was significantly related to the amount of maxillary advancement and severity of pre-surgical maxillary hypoplasia, while mandibular relapse was significantly related to maxillary dento-skeletal relapse. Successful clinical application of this procedure therefore requires consideration of both the surrounding dento-skeletal changes and the traction force system.

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Mitral annular calcification (MAC) is a common condition in elderly subjects that sometimes causes degenerative mitral valvular diseases. To investigate the early histopathogenesis of MAC, we examined 180 consecutive autopsies of elderly subjects. After a macroscopic and radiological examination, 5-mm-thick serial tissue blocks obtained from the mitral annulus were examined in all MAC cases. Five cases without MAC were also studied using histology, immunostaining, electron microscopy, analytical electron microscopy and the TUNEL method. The incidence of MAC in females (23%) was higher than that in males (15%). Most MAC was located at the posterior cusp (91%). The mitral annulus showed signs of microscopic calcification and lipid-deposition in some degenerated areas in all of the cases without MAC. The interstitial cells were positive for vimentin and partially positive for smooth muscle actin, indicating the myofibroblastic differentiation. Ultrastructural studies showed an abundance of cellular degradation products and foci of calcium- and phosphorus-deposition on these products in the interstitium. Several interstitial cells tested positive for both single-stranded DNA immunostaining and the TUNEL reaction. In conclusion, the microscopic calcification of mitral annulus is an early stage of MAC and caused by calcium-deposition on cellular degradation products, probably released from apoptotic or necrotic interstitial cells.

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Bone-tendon-bone (B-T-B) type grafts were prepared for ligament reconstruction by harvesting the radius from rats, wrapping both ends of each bone with a laboratory film leaving only the central 10 mm exposed, and demineralizing the central part by immersing the bone in 1.75% HCl solution. In the grafts prepared, the central part of the bone became semi-translucent and flexible while the ends remained as hard bone tissue, thus forming a B-T-B type graft. The tensile strength of the grafts was greater than that of the medial collateral ligaments of the rats and about the same as of their anterior cruciate ligaments. No inflammation or other adverse reaction was noticed in experimental subcutaneous transplantation and the grafts showed excellent biocompatibility. In experimental ligament reconstruction, the test animals did not show any impairment on gait. There was invasion of fibroblasts into the graft at 4 weeks, and the fibroblasts were found through the whole graft and what looked like ligament tissue could be seen macroscopicaly at 8 weeks. Besides, bone tissue had infiltrated into the inside cavity of the non-demineralized part of the graft and proliferation, resulting in good bone union. The results obtained suggest that the grafts prepared in this study have a sufficient potential as B-T-B type grafts for ligament reconstruction

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Purpose: Electrical potential may facilitate the moving of corroded metal ions across radicular dentin to cause allergic reaction. This study was to investigate the effect of electrical potentials on the penetration of silver and copper ions through radicular dentin. Materials and Methods: Eighty-eight dentin discs were prepared from intact premolar teeth and placed between two containers of the model. One container was filled with copper and/or silver solution. Another container was filled with 0.9% sodium chloride solution. Five levels of electrical potential were applied to the model at 37°C for 1 and 24 hrs. Then silver and copper ions in sodium chloride solution were measured by ICP-ES. The data was analyzed by one-way ANOVA with Tukey comparison test and student’s t-test (P<0.05). Results: The concentrations of metal ions significantly increased as the electrical potentials increased when above 250 mV were applied after 1 hr. The concentrations of silver ions were significantly greater than those of copper ions. Low concentrations of silver and copper ions were detected after 24 hrs at 125 mV level. Conclusions: These results suggest that the penetration of corroded silver and copper ions through radicular dentin caused by intraoral potential might be minimal.

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The purpose of our study was to utilize the dynamic finite element analysis to clarify the difference between Improved Super-elastic Ti-Ni alloy Wire (ISW) and Stainless Steel Wire (SSW) on occlusal force transmission during orthodontic treatment. ABAQUS/Standard was used to analyze three finite models over a 30-ms period: ISW, SSW, and wireless models; which consisting of premolar, molar, periodontal ligament (PDL), and alveolar bone. Wire model was established by beam element. A Joint C, which exhibits viscoelasticity to buffer occlusal force, was applied between the wire and bracket. The load was applied on the occlusal surface. At load withdrawal point, the average amounts of von Mises stress on PDL in three models were of the same value. However as time progressed, the stress in wireless model became higher than ISW and SSW models. In contrast, as time progressed further, the stress in SSW model became higher than the other two models and maintained its higher level until the end of analysis. Results showed that high damping capacity of ISW had an ability to buffer the transmission of occlusal force to the PDL. Besides, the dynamic analysis demonstrated an advantage to investigate the stress alterative response between models versus time period.

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Hypophosphatasia (HOPS) is a heritable disorder characterized by defective skeletal mineralization, deficiency of tissue-nonspecific alkaline phosphatase (TNSALP) activity and premature loss of deciduous teeth. In a previous study, we detected missense mutations in the TNSALP gene of a patient who inherited the F310L and the V365I mutation with severe periodontitis and childhood HOPS. Expression of the mutant V365I TNSALP gene using COS-1 cells demonstrated that the protein translated from the mutant had undetectable ALP activity. In the present study, we characterized another ALP enzyme translated from the mutant F310L and compared it with the ALP in the patient’s serum. The COS-1 cells transfected with the F310L and co-transfected with F310L and V365I (F310L/V365I) exhibited levels of 67% and 31%, respectively, with the enzymatic activity of the wild-type taken as 100%. In the thermostability test, TNSALPs in the COS-1 cells transfected with the mutant F310L or F310L/V365I were significantly more heat labile compared with that of the wild-type. Moreover, ALP from the patient’s serum was also more heat labile than normal ALP. These results suggest that the protein translated from the mutant F310L, in addition to the mutant V365I, may be responsible for the expression of symptoms of the childhood-type HOPS.

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Mechanisms of disc displacement in temporomandibular joint (TMJ) internal derangement (ID) in mandibular asymmetry have not been clearly defined. This study examines the degree and direction of disc displacement and their relationship with vertical asymmetry in terms of both clinical and biomechanical aspects. A retrospective study of disc displacement was performed in 31 mandibular asymmetry patients using MR imaging. The degree and direction of disc displacements on the shifted side and contralateral side TMJ were investigated with the degree of vertical asymmetry. Furthermore, three-dimensional finite element models of entire mandible include TMJ and maxillary teeth in occlusion were created to simulate displacement of the articular disc during clenching condition. The direction of displacement on the shifted side and contralateral side were significantly different. Articular disc has tendencies to displace more on the shifted side even in mild degree of vertical asymmetry. The degree of displacement was correlated with the amount of asymmetry. The MR results were consistent with the tendencies of disc displacement predicted from the finite element models. We suggest that disturbance in the direction of stress distribution through asymmetry of the mandible is one of the mechanisms related to disc displacement.

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Clinical experience suggests that successful orthodontic tooth movement can be produced with a threshold for force duration at about 6 hours, however, the changes in the periodontal ligaments (PDL) during this period is still unclear. Nitric oxide (NO) is a marker of signal transduction relating to bone remodeling. The aim of this study was to observe the initial response of NO synthase (NOS) when PDL equilibrium would be broken against light continuous orthodontic force. Rat maxillary first molars were moved mesially with 2 gf Titanium-Nickel closed coil springs for 1, 3 and 6 hours. The number of NADPH-diaphorase positive cells in PDL was counted for investigating NOS activity. At the control group, NOS activity in the distal area of the PDL was significantly higher than that of the mesial area (P<0.001). The activity of mesial area increased at 1-hour group (P< 0.01), while the activity of distal area dropped down at 3- and 6-hour groups (P 3-hour<0.05, P 6- hour<0.001), compared with the control group. These results suggest that 1-3 hours would be the threshold of force duration for tooth movement with light continuous force

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This study was conducted to investigate the effects of estrogen and progesterone on spatial memory in ovariectomized female rats, specifically, on memory impaired by the cholinergic antagonist scopolamine. Forty-one female rats were divided into five groups: ovariectomized (OVX), estrogentreated after ovariectomy (OE), progesteronetreated after ovariectomy (OP), estrogen-progesterone- treated after ovariectomy (OEP), and the sham control group (Control). The animals were trained on an eight-arm radial maze with four arms baited to assess both working and reference memory performances. The OE and OEP groups showed significant improvement in the ability to perform a spatial memory task over the OVX group (P<0.05). Spatial memory in the OP group did not differ from that in the OVX group. After thirty- two trials were conducted and all rats learned the eight-radial maze task, scopolamine hydrobromide (0.2 mg/kg i.p.) was administered prior to retesting. After scopolamine injection, the OVX group showed an increased number of working memory errors, reference memory errors than the other groups (P< 0.05). The OE, OEP and OP groups showed significant improvement in spatial impairment induced by scopolamine. These findings suggest progesterone alone or in combination with estrogen, improved scopolamine-induced impairment of working memory and reference memory as effectively as estrogen supplementation.

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Hyperactivation and acrosome reaction are prerequisite steps for sperm to be able to fertilize an oocyte. In mammals, hyperactivation is defined as a movement pattern seen in spermatozoa at the site and time of fertilization. The objectives of the present experiments were to analyze the process of hyperactivation and to investigate its relationship with progesterone evoked intracellular calcium concentration ([Ca²⁺]_i) increase and their implications with infertility. After capacitation the sperm from patients, when compared with donor’s sperm, showed decreased percentage of hyperactivated sperm, molitily, progressive motility, and curvilinear velocity (VCL). On the other hand, the linearity (LIN) was increased. Amplitude of lateral head displacement (ALH) and [Ca²⁺]_i increase (peak and plateau from baseline) showed good correlation in patients with infertility. These data suggest that impaired hyperactivation might be involved in the pathophysiology of infertility.

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Runx2/Cbfa1 is essential for osteoblast differentiation and bone formation. Runx2 null mice (Runx2^-/-) completely lack mineralized tissue and die soon after birth, whereas Runx2 heterozygous knock-out mice (Runx2^+/-) stay alive but show morphological defects in the skeletal system as observed in cleidocranial dysplasia (CCD) in humans. The aim of this study is to elucidate the role of Runx2 in adult mineralized tissue and also to reveal the distinct features of heterozygous deletion of Runx2 in response to tooth movement. Therefore, we examined the cranium, tooth and the periodontium in adult Runx2^+/- using soft X-ray and micro-CT. In addition, tooth movement induced by mechanical loading was evaluated. In adult Runx2^+/-, crown: root ratio of the first maxillary molar was significantly lower than that of wild type (WT). Irregularities in root morphology was also observed. The cranium was narrow with thin parietal bone compared to WT. Mechanical stressinduced tooth movement was similar between Runx2^+/- and WT in terms of movement distance. However, while rotational movement between the first and third week was increased in WT, it was not altered in Runx2^+/- mice. These data indicate that Runx2 plays a role in cranium and the tooth development in adulthood.

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