Conventional plastic teeth so far used as artificial denture teeth have a disadvantage of reduced esthetics through prolonged wearing because their wear resistance and coloration are both lower than those of porcelain teeth.
In recent years, high-strength plastic teeth have been developed to improve on conventional plastic teeth, and are now applied in clinical practice.
However, decreased esthetics of artificial teeth has been observed in some clinical cases due to discoloration of these high-strength plastic teeth
In this experment, high-strength plastic teeth were immersed in turmeric solution to examine their coloring disposition in vitro.
It was consequently reveal that the coloring disposition of high-strength plastic teeth was slightly lower than of conventional plastic teeth but considerably high as compared with porcelain artificial teeth.In addition, the coloring disposition of artifical teeth for specimen treated with ultrasonic cleaning every day tended to be lower than those which were not cleaned.

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Age changes of cells of the periodontal ligament adjacent to the cementum were observed by transmission electron microscope. Morphometric analysis was processed in the 20, m area of the periodontal ligament from the cemental surface. Forty human permanent teeth aged from 13 to 73 years were used in this study. The results were as follows.
1.Cells of the periodontal ligament adjacent to the cementum showed a densely cellular layer with functional differentiation.
2.Age changes on the cell density, nuclei and cytoplasms were not significant.
3.With respect to organelles, there was little age changes of the number in mitochondrias, but the size of cross-section increased in old age. No significant statistical differences were shown in the size of rough-surface dendoplasmic reticulums between in the young and the old.

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[in Japanese]

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In most nursing homes, for the aged, oral hygiene is left to the residents and the staff. Especially it depends on the efforts of individual staff members. Therefore it is important for the staff to learn oral hygiene for the residents. The purpose of this study was to investigate the level of awareness of the nursing staff of the oral hygiene of the residents.
A questionnaire was mailed to 110 staff in 11 nursing homes for the aged (9 in Saitama and 2 in Tokyo), 100 replied, 15 males and 85 females. They had worked in nursing homes for 5.7 years on average. They answered questions on the dental and denture hygiene status of the residents, on the necessity of instructing the staff in dental and denture hygiene of the residents, and on the need for the staff to perform oral hygiene for the residents.
The results were as follows:
1. There were no dental professionals in any nursing homes, and only two nursing homes were voluntarily visited once or twice a month by dentists. In none of the nursing homes were staff members instructed in oral hygiene of the residents, even if it was necessary.
2. Of 100 staff members, 66 had not been trained in oral hygiene for the residents. Fifty-four had been trained in oral hygiene for themselves. Thirty-four had not been trained in oral hygiene for either the residents or themselves.
3. Seventy-nine thought that they did not have enough knowledge of oral hygiene for the residents. The ratio of the staff members who thought that they had enough knowledge of oral hygiene for the residents was higher in the staff members who had been trained in oral hygiene of the residents than in the staff members without training. Ninety-seven hoped to receive training in oral hygiene for the residents.
4. The staff members' evaluation of the residents' oral hygiene was that only a few residents maintained good oral hygiene. The authors classified the residents into 2 groups according to their level of oral hygiene in order to evaluate the difference between the oral status of the 2 groups. The 2 groups were as follows: the residents whom the staff thought could keep their natural teeth and dentures in good condition by themselves (group A), and the residents whom the staff thought could not keep their natural teeth and dentures in good condition by themselves (group B). The staff thought that oral hygiene was better in group B than in group A. Especially the staff who had been trained in oral hygiene of the residents stated this. Fifty-one replied that cleaning of natural teeth and dentures of group A was performed by the residents themselves. Fifty-eight replied that cleaning of natural teeth and dentures of group B was performed by the staff. It was thought that good oral hygiene in group B was maintained by the staff. These findings demonstrate that instructions to the staff for oral hygiene were effective for oral hygiene of the residents.
5. Eighty-seven thought it was necessary for the staff to clean residents' natural teeth and dentures. Especially 62 percent of the staff members who had been trained in oral hygiene of the residents firmly believed so.
6. At first 35 found oral and denture cleaning distasteful. At present 79 were satisfied with it. Eighty-one hoped to perform the oral hygiene of the residents.
These findings demonstrate that training the staff in cleaning natural teeth and dentures by dental professionals is necessary and effective for daily oral hygiene in the nursing homes for the aged. Measures for facilitating oral hygiene and methods of improving it are necessary to reduce the burden of providing it.

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Many tooth stumps are found when we are treating elderly patients. This study investigates the factors that allow tooth stumps to retain by examining the condition of the root surface and root canal of the tooth stumps after treatment. The subjects are a total of 376 outpatients who visited the Department of Geriatric Dentistry of Nippon Dental University.
Our findings are as follows;
Tooth stumps were detected in 72 patients or 19. 1% of the total. It was found that root surface treatment was due on 134 (74%) of the 180 tooth stumps found. Radiopadue images due to the existence of fillings in the root canals were not observed in 79 (58%) of the total number of the remnants.More stumps were found in frontal areas than in molar sockets. The largest number of stumps was found in upper and lower canines on each side of the upper and lower jaws. The number of stumps showed an increasing tendency with aging of the patients. The patients with stumps were as healthy as other outpatients of our department. If stumps are left. The oral cavity environment will deteriorate, thus causing focal infection. Appropriate steps should be taken to prevent the infection.

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This study was performed as a preliminary investigation for the dental care service center for the homebound elderly in Chiba-city.
The general care and oral health status of the selected homebound elderly (n = 50, aged 54-93, mean age = 78.5, 66% female) living in Chiba-city were assesed.
Interviews and oral examinations were performed by a team consisting of a dentist, a health nurse and a dental hygienist.
The purpose of this paper was to analyze the subjects' dentition, eating activities of daily living, their prosthetic treatment needs and professional consideration for dental treatment. The results were as follows:
Regarding their dentitional condition, more than half the subjects over 60 years old had remaining root only or were edentulous in the Maxilla. Similar results were observed in Mandibula in subjects 75 years of age and over. The subjects who requested new dentures or asked for repair of their dentures account for nearly 50% of all subjects of 70-79 years. However, the percentage of subjects who requested new denture or denture rapair was less among those aged 85 years and over. As regards general treatment, most of the elderly requested of dental treatment until the age of 70, whlie these treatment needs declined markedly from the age of 80. Until the age of 70th, most of the subjects would be accepted for treatment by dentists in dental clinics. The number of subjects for whom treatment were judged to the necessary or impossible increased from the age of 80.
In eating activities (total independence, partial dependence, total dependence) with ADL, the activity of denture wearers was higher than the subjects who need dentures.
The main reason of no denture wearing for the subjects who were edentulous or lacking many teeth (more than 2/3 jaw) was the abandonment of dental treatment. Other reasons were no need of dental treatment, no means of transportation and no person to take them.
On the other hand, on examination by dental professionals it was judged that dentures would be made at the dental clinic for 75% of the maxilla group and 53% of the mandible group of untreated subjects. All of the 23 subjects who wanted dental treatment could be treated in a dental clinic.
According to the judgement by dentists, 12 subjects were judged to have no need of dental treatment of the 20 persons who answered that they needed no need dental treatment.
Of the 12 people who answered that they had give up dental treatment, the only 4 subjects were judged to not need or to be unable to receive dental treatment. Of the subjects who answered that they had no means of transportation or no one to take them, none was judged to be unable or not needing treatment,
These results indicated that the oral health problem for the elderly were not only practical dental treatment, but also social communications in relation to general circumstances of quality of life in the aging society.

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We surveyed 22 patients admitted for dental treatment in Kanagawa Dental College Hospital from April 1987 to March 1992, excluding the patients selected for general anesthesia.
1. The ages of the patients ranged from 39 to 83 years. Eight cases (36.4%) were in their 50s and 10 cases (45.5%) were in their 60s. There were 11 males and 11 females.
2. Among their complicated disorders, 13 (59.3%) patients had sequelae of cerebro-vascular attack. All the patients except one were prescribed with several habitual drugs by their physicians.
3. Twelve patients (54.5%) were managed by internists, but one patient did not have a regular physician.
4. Most patients could not walk, and needed canes, devices, wheel chairs etc. Only 2 patients could walk without help.
5. For daily living, 8 patients needed the help of their spouses, and 6 patients did not need any help from others. Attendants were necessary for 21 patients (95.5%) during hospitalzation.
6. In all cases, periodontal disorder was observed in some degree.
7. Durations of hospital admission ranged from 3 days to 29 days (mean: 11.8 days).
8. Most cases needed dental treatment as out-patients or by dentist's visits.

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Dendelion Dental Office has been established for the aged bedridden people living at home in Katsushika-ward. For a period of one year and 10 months, 52 patients were subjected to tooth extraction in the office under the general control by dental anesthesiologist. Investigation was performed on the changes in blood pressure, pulse rate, and percutaneous oxygen saturation level during tooth extraction of these subjects.
There were 52 patients, 28 males and 24 females, with an average age of 76. 9 years. Their diseases resulting from laying alone and complications were overwhelmingly cerebrovascular disorders and hypertension respectively.
The numbers of tooth extracted at one treatment were 1 in 50% of the subjects and 2 in 25% of the subjects. The total numbers of teeth extracted were 1 in 33% of subjects and 4 in 16% of subjects. The local anesthetic used for the majority of subjects was 2% lidocaine supplemented with 80, 000-fold diluted epinephrin.
The average treatment time was about 19 min and no subject was treated for more than 30 min. Values measured 5 min after transferring to the dental treatment chair were used as the controls. When the differerential rates of systolic and diastolic pressures at extraction were examined, both showed increasing tendencies at injection of a local anesthesia, and at extraction procedures. Especially, the diastolic pressure showed a significant increase at extraction procedures. There was no significant fluctation in the pulse rate or percutaneous oxygen saturation degree. During treatment, blood pressure and pulse rate are the essential monitoring parameters for all patients.
Since oxygen saturation in the arterial blood is considerably lower in old people than in young people, old peoples capacity to supply oxygen to myocardium are significantly lowered. Therefore, the usage of a combination of apparatus to measure percutaneously the oxygen saturation degree is very useful for old people.

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[in Japanese]

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Radiographic diagnosis of edentulous jaws in addition to ocular inspection and palpation can allow detection of the presence of impacted tooth or residual root which may constitute the cause for an offensive feeling appering after treatment. This has encouraged a large number of studies in foreign countries for the evaluation of the effectiveness of panoramic radiograpy in the edentulous patients. In Japan, however, this line of study does not seem to have been satisfactorily undertaken. This study was designed to investigate the detectability of dental abnormalities such as tooth impaction by panoramic radiographic diagnosis at the site of the defect in 600 partially and jully edentulous patients.
Abnormalities were detected in 56 (9.3%) of the 600 patients. The number of abnormalities totaled 87. The most frequent was residual root (59.8%). It was followed by impacted teeth (24.1%). The presence of foreign matter and radiopacity amounted to 8% each. In age distribution, patients in their sixties were predominant (32.1%), followed by those in their fifties (28.6%) and seventies (16.1%). Patients above 50 years of age amounted to 80.4% of the total number of patients. The number of patients and the frequency of abnormalities were proportional in the group of bimaxillary edentulous patients. In the group of unimaxillary edentulous patients, the frequency of abnormalities was higher in spite of the low ratio of patients in this group to the total number of patients. There was no differnce in the incidence of abnormalities between the upper and lower jaws. Residual roots were frequently present in the upper jaw. Impacted teeth were frequent at the region of the lower third molar.
Abnormalities in edentulous jaws could be detected by panoramic radiography, though the incidence was not demonstrably high. The results suggest that panoramic radiographic diagnosis is useful for the prevention of offensive signs that may appear after insertion of dentures.

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