In order to know the relationship between inorganic ion composition of saliva and dental caries prevalence, saliva from children was studied. The saliva samples were collected from 30 subjects aged 3 to 18 years. Each inorganic ion concentration and pH of saliva was measured and their relationship to dental caries was studied. The results were as follows: 1. Significant relationship was noted between ammonium ion concentration and caries prevalence. It was suggested that the ammonium ion was derived from decomposition of urea or amino acids. 2. Although a significant relationship was also noted between potassium ion concentration and caries prevalence, its direct process is unknown. 3. The sodium ion concentration in saliva increased with age, which implies its relationship to the development of the hormonal system.
We had participated in the charitable operation for the patients with cleft lip and palate and technical suidance in Vietnam in 1998 for 2 weeks. The project was a part of the activities of the Japanese Cleft Palate Foundation, which were performed as part of the Official Development Assistance (ODA) of Japan, and was aided by state subsidy of the Ministry of Posts and Telecommunications, the Ministry of Foreign Affairs and the Ministry of Education and so on. Our team consisted of members of Tokyo Dental College, Iwate Medical University, Dalhousie University, and our university. The hospital we visited was Odonto-Maxillo-Facial Center in Ho Chi Min City, which had 7 clinical departments, 36 dental units, 60 beds in ward, and 75 doctors in total. This hospital dealt with all kinds of disease in connection with oral and maxillo-facial area including dental caries, periodontal disease, maxillo-facial injuries, and maxillo-facial anomalies. Forty-five patients with cleft lip and palate were operated on during our stay in Vietnam. The age of these patients was higher than that in medical advanced countries because of economic problems and insufficient medical institutions. In some cases, surgery was performed in collaboration with local doctors, which means technical suidance leads to more effective treatment.
Latin anatomical names ofFossaeandFoveaein the skeleton were analyzed and compared with Japanese anatomical names for better understanding of the structures of the human body and for possible revision in the future. The conclusions were as follows: 1. In general, round excavations were calledFoveae (singular: Fovea), and nonround excavations were calledFossae (singular: Fossa) . Some shallow excavations for articulation and some shallow excavations with the names which indicate their contents were calledFoveaeeven though they were not round. 2. Each name ofFossaecontained the word which indicates form, location or content ofFossa, the bone (or osseous structure) which articulates withFossa, or the muscle which is attached toFossa. 3. Each name ofFoveae contained the word which indicates location, content or articulation ofFovea, the bone (or osseous structure) which articulates withFovea, or the muscle (or muscular trochlea) which is attached toFovea. 4. The Japanese name which corresponds toFossa caninashould be changed from Kenshi (canine tooth) =ka (fossa) to Kenshikin (canine muscle) = ka or Koukakukyokin (levator anguli oris muscle) =ka. 5. The Japanese name which corresponds toFossa pterygopalatinashould be changed from Yoku (wing) = kougai (palate) = ka (fossa) to Yokutotsu (pterygoid process) = kougaikotsu (palatine bone) = ka.
A statistical survey based on laboratory records was performed on the number of indirect restorations fabricated at the dental hospital of Tokyo Medical and Dental University from April 1 to September 30, 1997. A comparison was also carried out with a previous survey, which had been carried out in 1986, in order to detect any change and possible alterations in the near future. Based on the results of this statistical survey, the conclusions were as follows: 1. A total of 9, 126 indirect restorations were fabricated during the six month period in 1997; among them, 8, 007 (87.7%) restorations were covered by health insurance and 1, 119 (12.3%) restorations were not. 2. The most common restoration was the cast post and core (28.6%), followed by full crowns (18.5%) and removable partial dentures (15.6%) . On the other hand, the least number were post crowns (0.03%) and resin jacket crowns (0.2%) . 3. When making a comparison with the data in 1986, an increase in the number of removable partial dentures and a decrease in the number of inlays were the most distinctive features. 4. For anterior teeth, resin-veneered crowns were most common, especially for lower teeth. The percentage of restorations, which were not covered by health insurance, decreased from 45.0% (in 1986) to 12.3% (in 1997) .
A statistical survey based on laboratory records was performed on the number of fixed and removablepartial dentures fabricated at the dental hospital of Tokyo Medical and Dental University from April 1 toSeptember 30, 1997. A comparison was also performed with a previous survey, which had been carried outin 1986, in order to detect any change and possible alterations in the near future. From the findings of this statistical survey, the conclusions were as follows: 1. Atotal of 2, 478 fixed and removable partial dentures were fabricated during the six month period in 1997. 2. The 3-unit fixed partial denture (bridge) was most common (63.1%) and the number of bridges decreased as the number of units increased. 3. For the single missing tooth, a fixed bridge was more popular (81.0%) than a removable partial denture. 4. For two missing teeth, there was no difference between the number of fixed bridges and removable partial dentures. 5. The percentage of fixed and removable partial dentures, which were not covered by health insurance, decreased to a large extent in comparison with the survey in 1986.
The purpose of this study was to investigate the oral health status and health behavior of the adult population in the workplace. In 1998, oral health examination of 388 workers (male: 287, female: 101) at a government office was performed. A questionnaire was administered to obtain data regarding oral symptoms and health behavior. The results were as follows: Overall, 48% needed treatment for dental caries, 44% needed calculus removal, and 23% needed treatment for periodontal disease. Although there were no oral health complaints, 20% had early caries, 40% had dental calculus, and 19% had periodontitis. Compared to males, more females brushed their teeth, had home dentists (44%) and received more regular dental health check-ups at least once a year (48%) .For males, those with home dentists had higher FT and DMFT in the twenties and thirties. There was no relationship between oral health status and regular check-ups in both males and females. The results revealed that receiving regular dental check-ups from home dentists was not popular in Japan. Further, the role of home dentists is not preventive oriented. It was concluded that it is necessary to provide regular oral health examination and health promotion programs for adult population at the workplace in Japan.