This study examines the effects of denture adhesive on the retention and stability of complete dentures and the masticatory function. The authors estimated the stability of complete dentures from 3-dimensional (3-D) denture movement and rotational denture movement and additionally the masticatory function from cycle time and chewing time. Six edentulous subjects who participated in this study had old and newly fabricated complete dentures. Upper denture movement was recorded using a 3-D motion capture system while chewing 3 kinds of food (peanuts, fish paste, raisins). Both the new and old dentures showed that using a denture adhesive contributes to reducing 3-D denture movement, rotational denture movement and chewing time during chewing the various foods. The cycle time in new and old dentures was statistically unaffected by applying denture adhesive. There was no statistically significant difference in improvement in 3-D denture movement or rotational denture movement between the new and old dentures, for any of the foods. This study observes the overall effect of denture adhesive during use for both dentures. The results of this study suggest that denture adhesive contributes to reducing denture movement and so improves chewing function.

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The aim of this study is to examine the relation between mortality and the existence of incineration plants and dioxin released from the plants in 590 municipalities across Japan. The concentration of dioxins in emissions from incinerators, the amount of dioxins per population, the cumulative amount of dioxins, and the cumulative amount per land area were used as dioxin-related municipal indices. Age-adjusted mortality rates from all causes and five major disease categories by municipality in 1995 were used as health indices. The relation was examined using t-test, analysis of covariance (ANCOVA), correlation coefficients and multiple linear regression analysis, considering the effects of cities’ socioeconomic conditions. Although municipalities with plants had significantly higher mortality from female stroke and lower mortality from male cancer at all site and lung than municipalities without plants, these differences were not significant in ANCOVA with socioeconomic indicators. The significant relation between mortality and dioxin indices in correlation coefficient was ruled out when the socioeconomic conditions were adjusted in multiple regression analysis. This study did not show the statistical relation between increased mortality from major causes and the existence of incineration plants and dioxins from the plants at the municipal level.

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The purpose of this study is to evaluate the masticatory muscle activity and mandibular movement during function in marginal mandibulectomy patients. Three marginal mandibulectomy patients and three healthy subjects participated in this study. The activities of the temporalis (TA) and masseter muscles (MM) on the normal and resected sides during maximum voluntary clenching (MVC) and gum chewing (Gch), and mandibular movement during Gch were analyzed. Paired t-test, Student’s t-test and one-way ANOVA were performed at P < 0.05. For MVC, integrated EMG (iEMG) in patients was lower than in healthy subjects. When iEMG of each muscle activity in patients was compared, TA activity on the resected side was greater than that of MM. There were no differences between the normal and resected sides in TA or MM. For Gch, no differences in iEMG, burst or chewing time were found between patients and healthy subjects. MVC was greater than Gch in healthy subjects, but no difference was found in patients. The range of mandibular movement along the X axis in patients was greater than in healthy subjects. Within the limitations of this study, EMG activity in patients during MVC was remarkably lower than that in healthy subjects, and altered mandibular movement was observed.

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Etiology of sarcoidosis remains unknown. A trigger factor from Propionibacterium acnes causes a cellular immune response in some sarcoid patients but not in nonsarcoid subjects. We examined whether experimentally induced hypersensitivity to the trigger factor gives rise to granulomas. Female C57BL/6 mice primed intravenously with P. acnes or not were sensitized with recombinant-protein RP35, a fragment of P. acnes trigger factor, and complete Freund’s adjuvant. In controls, RP35 was replaced with P. acnes or one of two control proteins. In primed and unprimed mice, pulmonary granulomas were found in some of the mice sensitized with RP35 or P. acnes but in no control-protein-sensitized mice. Detection of pulmonary granulomas (25-57%) did not differ significantly between mice sensitized with RP35 or P. acnes, primed or not. No difference in popliteal lymph-node-cell reactivity and serum antibodies to these two antigens was found between mice with and without pulmonary granulomas. P. acnes was cultured from the lungs of 8 (33%) of 24 untreated mice. The recombinant trigger-factor protein of P. acnes caused pulmonary granulomas in primed and unprimed mice sensitized with the protein and adjuvant. Sarcoid granulomas may form during hypersensitivity to antigens of P. acnes indigenous to the affected organ.

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The parasympathetic nerves regulate colonic motility and defecation. The vagal nerve controls the right colon and the pelvic nerve permeates the left colon and rectum via the rectal branches of the pelvic plexus (RBPP). This investigation aimed to measure the functional changes of the colon and rectum after RBPP-transection for over six months. RBPP-transection was performed in 15 dogs. Five dogs each were sacrificed immediately, one month, and six months after RBPP-transection. The stool condition, colorectal transit, defecation reflex, colorectal response to electrical stimulation, and pathological degeneration was investigated prior to, one month after, and six months after RBPP-transection. Four of the 5 dogs observed had loose stool one month after RBPP-transection, and one of the 3 had recovered six months later. Half transit time (HTT) at transverse colon got longer in six of the 8 in one month. Six months later, HTT got shorter in three of the 4 than that of one month. Defecation reflex was not observed one month after RBPP-transection, but noted in two of the 5 six months later. These results may suggest that vagal nerve compensates for the oral site of the left colon after denervation of the pelvic nerve which is originally distributed.

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To explain the pain and dysfunction of neck during jaw movement associated with malocclusion, the physiologic relationships between jaw and cervical movement should be understood. However the complicated reflex effects made it difficult to investigate the biomechanical relationship between the head-neck components. For this reason we have created a model for mechanical system dynamic analysis of the normal stomatognathic system to assess the biomechanics of the cervical movement and muscle activity during jaw movement. We have also statistically validated the model and quantitatively verified the model to the human subject by the amounts and conditions of cervical muscle activity. During jaw openingclosing phases the movement of the model was highly correlated to the subject with an identical movement. However low consistency was achieved during intercuspid phase. These findings indicate the establishment of a valid system, which can be used to evaluate the biomechanical relationships between jaw and cervical movement. Moreover the model verification of cervical muscle activity indicate the mechanical action of jaw can be the primary factor to modify cervical muscles, and cervical muscles coordinate to resist changes in head balance during jaw movement to maintains head posture.

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