The relationship between maxillo-facial patterns and function of the masticatory muscles was evaluated using electromyography, in 16 women with functional normal occlusion and 16 girls with chronological normal occlusion half of them had the dolico facial pattern and the others had the brachyo facial pattern by Ricketts analysis. For the electromyography, loads of 1, 2, 3, 4, and 5kg were applied to the mandible, and muscular activity waves were obtained from the masseter muscle and the anterior belly of the temporal muscle during isometric contraction by surface electrode induction. The median frequency value (MFV) in a frequency curve obtained by high-speed Fourier transform of the electromyographic waves was set to the evaluation index. The MFV at each applied load was higher in the adult brachyo facial pattern group than in the adult dolico facial pattern group in both the masseter and temporal muscles, whereas the differences in the MFV were slight in the child group at a 5% significance level. The child group showed approximately half the incidence of significant correlation coefficients in comparison with the adult group and a large standard deviation without marked differences in the facial patterns due to their individual differences in growth with a 5% significant level. The adult brachyo facial pattern group showed a high regression coefficient of the MFV in the masseter muscle according to the increase in the amount of the applied load. Although differences in the cooperative contraction patterns similar to those in the adult group were observed in both the child dolico and brachyo facial pattern groups, no marked significant differences were observed in the child group, who had large individual differences due to their immature growth.

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This study examined the effects of storage conditions such as time course, temperature, fluorescent light, and darkness on the components and antibacterial activity of formalin guaiacol (FG) used in endodontic treatment. We measured the quantities of formaldehyde and guaiacol in FG and antibacterial activities against Staphylococcus aureus, Porphyromonas gingivalis, and Porphyromonas endodontalis. The components and antibacterial activity of FG in the brown or transparent tightly sealed containers were not affected by temperature or fluorescent light throughout the 4 week test. However, in the loosely sealed containers, formaldehyde and guaiacol in FG sample decreased remarkably within one week, not only in a temperature- and time-dependent manner, but also under fluorescent light at 20°C. Furthermore, the antibacterial activities in the FG sample were significantly attenuated in parallel with the decrease in formaldehyde levels. Fluorescent light caused color changes and crystallization of FG samples in the transparent containers. These results suggest that it is important to replace fresh FG every 5 to 7 days for endodontic treatment and that, in the dental office, it is advisable to store fresh FG in tightly sealed containers every 2 weeks to maintain its efficacy.

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Lateral loads exerted on the maxillofacial region by habitual postures and habits may cause lateral shift or deformity of the mandible. These loads were measured with a desktop dynamic-strain gauge (DPM-600, Kyowa Co.) connected to a small, highly sensitive pressure sensor (PSL-A type, Kyowa Co.), and recorded with an oscillographic recorder (RDM-100A, Kyowa Co.). Measurements were taken with a pressure sensor embedded in silicone impression material placed in a vinyl chloride resin bag, on which pressures were applied. A preliminary study was conducted to obtain a proportional constant and a conversion formula for load calculation. The subsequent main study included 20 healthy male volunteers for load measurement in 12 positions. The mean load exerted on the mandible was 43.7N when the subjects lay face down and approximately 20N when they sat resting the lateral part of the chin on the hand, indicating that these loads are greater than regular orthodontic forces.

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We evaluated the influence of molecular mass and degree of deacetylation of chitosan on the adsorption of Streptococcus sobrinus 6715 to saliva-treated hydroxyapatite (S-HA) by measuring the optical density of the bacterial cell suspensions released from saliva-treated hydroxyapatite. Twenty-five chitosan samples with different molecular masses (0.8-6kDa) and degrees of deacetylation (10-95%) were prepared for the study. We found that the inhibition of adsorption of S. sobrinus 6715 to S-HA correlated positively with the molecular mass of chitosan (R=0.876) and that the optimal degree of deacetylation was 50-60% for maximum inhibition of bacterial binding to S-HA. We also examined the effect of chitosan on zeta potentials of the oral bacteria and their surface hydrophobicities. It was observed that chitosan reduced the magnitude of the zeta potential and surface hydrophobicities of the oral bacteria. Thus, the results demonstrated that chitosan with a molecular mass of 5-6kDa and a degree of deacetylation of 50-60% might have the potential to act as an effective anti-plaque agent because of its polycationic properties.

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Physical and psychological evaluation have been required for TMD patients whose problems are multi dimensional. The questionnaire named the “TMJ Scale” was created to differentiate subjective TMD symptoms of patients. The purpose of this study was to clarify the reliability of the TMJ Scale for Japanese orthodontic patients with TMD and to differentiate the symptoms. Fifty orthodontic patients (average age 21y4m) with a chief complaint of TMD symptoms were compared with thirty patients (average age 21y1m) without TMD symptoms. The results were as follows: female patients in the symptom group in particular showed a higher degree of stress due to the chronic pain and abnormalities than those in the non- symptom group. Significant differences were observed in Pain Report, Joint Dysfunction and Global Scale at the 0.1% significant level, in Non-TM Disorder, Psychological Factor and Chronicity at the 1% level, and in Palpation Pain and Perceived Malocclusion at the 5% level in females. Few psychological problems were observed in male patients in the symptom group. Significant differences were observed in Range of Motion limitation at the 5% level in males. The differences in the psychological factors between male and female patients were clarified by using the TMJ Scale. These findings suggested that it was useful to differentiate the multiple symptoms, especially the psychological factors, by using the TMJ Scale for orthodontic patients with TMD.

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The purpose of this study to clarify the factors an effecting lip seal in Japanese adults with malocclusion. Sixty-three malocclusion patients aged 20 to 27 years were randomly selected and compared with fourteen normal occlusion controls aged 22 to 26 years old. The subjects were divided into a good seal group and a poor lip seal group by observing the distance between the upper and lower lip at rest. Results of this adult study were as follows; There were no poor lip seals in normal occlusion subjects. Significant differences were observed for tongue thrust (p<0.05) and mouth breathing (p<0.05) between the good lip seal group and poor lip seal group of malocclusion subjects. Adults with poor lip seal should be treated for their malocclusion prior to be other functional approaches to improving their lip seal.

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In a previous study, we demonstrated that angiotensin II (Ang II) inhibited voltagedependent calcium channels (VDCCs) currents (I_Ca) in hamster submandibular ganglion (SMG) neurons. In sinoatrial node cells, it has been reported that Ang II inhibits I_Ca by suppressing cyclic AMP production. In this study, to investigate the possible involvement of a cyclic AMP-cyclic AMP dependent protein kinase (PKA) pathway in the Ang II-induced inhibition of I_Ca, effects of Ang II were examined in SMG neurons after treatment with an activator and inhibitor of PKA. Neither pretreatment of neurons with membrane permeable cyclic AMP nor intracellular dialysis of PKA blocker attenuated the Ang II-induced inhibition of I_Ca. These results indicate that Ang II inhibited I_Ca via a cyclic AMP-PKA-independent mechanism in SMG neurons.

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