Oral health surveys were carried out on 409 people aged between 35 and 84 years at Kaida-cho, Fukuoka Prefecture. The purpose of this survey was to get baseline data showing the necessity of including oral health programs in the Health Check-up System established in accordance with the Elderly Health Law. Edentulous persons were not found in subjects under 55 years of age. The percentage of edentulous persons and the mean number of teeth present increased with age but the mean number of decayed teeth (about one and a half teeth on the average) was consistent between age groups. The percentage of persons with healthy periodontal tissues was very low. Probing pocket depths of 6mm or more were observed from 10 to 19% of persons in each age group and pocket depths of 4mm or more were observed in over 50% of persons aged 45 years and older. Almost half of the subjects had full and/or partial denture (s) and half were diagnosed as needing denture treatment. 13% of subjects had problems in their temporomandibular joints. Of these, almost all of them experienced a clicking sound. These results indicate that the prevalence of dental caries and periodontal diseases are relatively high even in younger age groups and that the mean number of missing teeth becomes higher in older people. It should be concluded, therefore, that oral health programs are necessary not only for the elderly but also for the younger generations.

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Dendritic cells were widely distributed in tissues including digesting organs. The dendritic cells in the tissues were able to be detected by specific antigens. The antigens were studied immunohistologically and protein chemically after oral immunizations. Results are as follows : 1. In the immunohistological study, the number of dendritic cells were increased in esophageal lamina propria, Peyer's patches and liver connective tissues after oral immunizations. 2. The increase in the dendritic cells in the immunohistological study were confirmed in the result in the protein chemical study, as well. 3. The results suggested that the dendritic cells in Peyer's patches and liver migrated with the stimulation after oral immunizations. The migration was not recognized in esophageal tissues. The dendritic cells in digesting organs, as Peyer's patches of small intestin and liver, may migrate with the stimulation after oral immunizations.

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Rat macrophages and cloned fibroblastic cells were stimulated with different concentrations of lipopolysaccharide (LPS) from Escherichia coli (E. coli) and supernatant from Porphyromonas gingivalis (P.g.) and Actinomyces naeslundii (A.n.) after ultrasonication. Amounts of interleukin-1 (IL-1) and interferon (IFN) secreted into the medium from the macrophages and the fibroblastic cells were measured in the course of time after incubation. Results are as follows : 1. In a stimulation with the low concentration supernatant of either P.g. or A.n., macrophages secreted a higher amount of IL-1 than the cells did in the case of the high concentration supernatant. 2. In the stimulation with the low concentration supernatant, the P.g. stimulated macrophages secreted a higher amount of IL-1 than the A.n. stimulated cells did. 3. The high or the low concentration supernatant stimulated macrophages secreted a higher amount of IL-1 than the LPS stimulated cells did. 4. With the high concentration supernatant, the P.g. stimulated fibroblastic cells secreted a higher amount of IL-1 than the A.n. stimulated cells did. 5. In a stimulation with the high concentration of P.g. supernatant, IL-1 secretion from macrophages was similar in level to that from fibroblastic cells. In the case of A.n., the secretion from macrophages was higher than that from fibroblastic cells. 6. In a stimulation with the high concentration supernatant, the amount of IFN secreted from macrophages changed in a similar proportion to that of IL-1 during the incubation. The amount of IFN secreted from the A.n. stimulated macrophages was higher than that from the P.g. stimulated cells. The results suggest that the amount of IL-1 secreted from macrophages and fibroblastic cells was higher in the stimulation with putative periodontpathogens' supernatant than that with E. coli LPS. The supernatant stimulated fibroblastic cells secreted IFN in the similar proportion to IL-1. Thus the results support the idea that P.g. and A.n. were important pathogens in periodontitis.

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The purpose of the study is to ascertain prevalence of mutans streptococci and Lactobacillus in school children using Dentocult SM and Dentocult LB, and also to determine the effectiveness of various caries activity tests, including Dentocult SM, Dentocult LB, Cariostat, Dentobuff and salivary flow rate, for screening children with high risk for dental caries. Dental caries were detected on a tooth-surface basis, and measurements of salivary buffering capacity and salivary flow rate in addition to microbiological tests were carried out on 387 school children aged 4 to 19 years in Kitakyushu City. The mean number of decayed deciduous tooth-surfaces (ds) and decayed filled deciduous tooth-surfaces (dfs) decreased significantly (p<0.05), but the mean number of decayed permanent tooth-surfaces (DS) and DMF tooth-surfaces increased significantly (p<0.01) with increasing age. The prevalence rate of mutans streptococci measured by Dentocult SM was about 80% in the 4-6-year-old group, and it gradually increased with age. The prevalence rates of Lactobacillus measured by Dentocult LB were about 50% in all age groups except for the 7-9-year-old group. The percentage of children with a Dentocult LB score of 1 or more was significantly higher (p<0.05) in the 7-9-year-old group than the other age groups. Mean numbers of decayed and/or filled tooth-surfaces were significantly higher (p<0.05, 0.01) in children with higher scores on the Dentocult SM, Dentocult LB and Cariostat tests than in those with lower scores. Especially, ratios of the number of decayed tooth-surfaces at the minimum scores of Dentocult SM against those at the maximum scores were highest in both deciduous and permanent teeth when compared with those of Dentocult LB and Cariostat. The mean numbers of DMF and df tooth-surfaces were significantly lower (p<0.05, 0.01) with increasing salivary buffering capacity measured by Dentobuff. Only in deciduous teeth were mean numbers of ds and dfs significantly lower (p<0.05) in children with higher salivary flow rates. Sensitivity and specificity in screening high risk children for dental caries were highest in scores of 1 or more on the Dentocult LB test than any other caries activity test when only one test was adopted. However, much higher sensitivity and specificity were gained (65.9% and 70.2% respectively) when Dentocult SM, Dentocult LB and Cariostat were combined. These results suggest that it is better to combine three caries activity tests for effectively screening 4-19-year-old people with high risk for caries. This might enable more efficient preventive care to be provided for selected children.

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This study was undertaken to examine the effects of nitrous oxide (N_2O) inhalation on tactile and pain thresholds measured on the buccal skin of human. The subjects consisted of 28 healthy men aged 23-28 years with a mean of 24.7 years and weighed 50-90kg with a mean of 65.1kg. The subjects were divided into four groups according to which of four gases they inspired, 30%, 50%, 65% N_2O mixed with oxygen, and 100% oxygen as a control. Nylon threads with three different diameters and lengths and analgesiometers were used for measurements of tactile and pain thresholds, respectively. The subjects were instructed to recline on a dental chair comfortably in the supine position. After ten minutes' rest, measurements were started three times each at 10-minute intervals during breathing room air as a control, during inhaling the respective concentration of N_2O and during withdrawal period. The data calculated as the maximum possible effect were statistically compared with those of the control group. The results obtained were as follows. 1) Thresholds of tactile sensibilities on the buccal region were increased to 34%, 34% and 17% up from the control in 30%, 50% and 65% N_2O gpoups, respectively, but there were no significant differnces from the control value. 2) Thresholds of pain sensibilities on the buccal region showed significant increases from control value and 100% O_2 group (control group) during N_2O inhalation period in N_2O groups except at 20 and 30 minutes' point in 30% N_2O inhalation. 3) In physiological variables, there was no significant difference from the control value and 100% O_2 group (control group) such as heart rates, blood pressure, respiratory rate and oxyhemoglobin in every N_2O administration. These results indicate that analgesic effects of nitrous oxide at the buccal region in human face exist even in 30% N_2O and these effects are enhanced in accordance with that dose although there are no effects on tactile sensibilities and cardio-pulmonary function.

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The recent development of biomaterials, especially of ceramics including hydroxyapatite has been remarkable. The present study was performed in oder to investigate histopathologically the healing process of the bone defects to porous hydroxyapatite granules (P-HAP granules) which was implanted into artificially created bone defects in domestic rabbits. The results were as follows : 1. At one week after implantation in bone defects, P-HAP granules could be observed in the granulation tissues composed of fibroblasts and collagen fibers. There was slight inflammatory cell infiltration. 2. At two weeks after implantation, P-HAP granules could be observed in the fibrous connective tissues. The formation of osteoblastic cells was seen around them. 3. After four weeks, P-HAP granules were encapsulated by new bone tissue and were directly connected with new bone tissue. Neither foregin body reactionnor inflammation cells infiltration was observed. 4. After six weeks, P-HAP granules were embedded in the new bone. Bone repairs were almost completed incontrol. The formation of new bone was rather expedited as compared with control. 5. Considering above results, it was suggested that P-HAP granules were non-inflammatory and non-stimulative. Further they had good tissue tolerance and osteogenic activity. In these investigations, P-HAP granules are considered to be useful as bone graft material for oral surgery.

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