We conducted overall research on the prevention and control of the progress of caries in children. The subjects of this study were children from 1 to 15 years of age. We conducted this study from June to October of 1999. We distributed the Cariostat®, Mucount®, dental examination forms and questionnaries among the departments of pediatric densitry at 29 colleges and universities in Japan. We also studied the content of oral examinations, the caries activity tests and the individual questionnarire surveys. Base on the result we conducted a statistical study on the subjects, especially on those in the survey ranging from kindergartner to junior high school students. We obtained the following conclusions.
1. There was a significant relationship in individual basis regarding Mucount®, CSI and Cariostat®, showing that these can be used for mesuring the actual state of the oral cavity, in other words the caries activity in the mouth.
2. Life style and social environment affected the risk of caries.
3. The awareness and knowledge of the children and parents were high, but not sufficient to be of actual use in individual basis.
4. We need methods that we can actually use for the prevention of caries.

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A study on the current status of dental treatment was conducted in a certain welfare institution for children with severe mental and physical disabilities in Tokyo over the past 19 years, and the results suggested that the caries prevalence rates tended to be low in a specific ward there. Thirty-five children (16 girls,19 boys) in that ward were selected for this study and divided into two groups according to feeding method: 25 in the tube fed group (11 girls,14 boys) and 10 in the orally fed group (5girls,5 boys). The subjects were clinically assessed in regard to oral hygiene habits, caries experience (DMF), and effect of the feeding method on the lisk of caries. The results obtained were as follows:
1. A simple method in which a toothbrush was used was effective in collecting saliva for Dentocult SM-Strip mutans.
2. The Oral Hygiene Index Simplified (OHI-S) and Calculus Index Simplified (CI-S) scores were significantly higher in the orally fed group than in the tube fed group, and there was no significant difference in the Deblis Index Simplified (DI-S) between. the two groups.
3. The numbers of decayed and filled deciduous tooth (de and the numbers of DMF per subject were low in both groups, and there were no significant differences between them.
4. Salivary streptococcus mutans levels were significantly higher in the orally fed group than in the tube fed group, but both groups were in the low-risk group.
5. The tube fed group was subdivided into two groups according to the age at which tube feeding had been started: a group in which tube feeding was started under three years of age and a group in which tube feeding had been started at three years of age or older. No significant difference in salivary streptococcus mutans levels was found between the two groups, but the group that started tube feeding under three years of age tended to have lower levels than the other group.

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In Japanese, the lower first molar erupted earlier than the lower central incisor before. The Japanese Society of Pedodontics (1988) reported contrary results for the eruption pattern. This phenomenon involves an important problem from a biological viewpoint, because the first erupted permanent tooth changed from the supplemental tooth (the first dentition) to the successional tooth (second dentition).
We investigated the eruption pattern of the central incisors and first molars in individuals to clarify the starting generation of this phenomenon. It was found that the “I” type, which the central incisor erupted earlier than the first molar, was increased in Japanese infants who were born in 1970's, and became 50% or more.
The comparison was made between the two previous studies (Okamoto,1934,1938; JSPD,1988)and among the pervious studies of other ethnic groups to discuss the change in the time of the eruption. The following conclusions were obtained: (1) The Japanese life style rapidly changed from traditional style to the European or North American styles from 1970 onward. This change of life style including eating habits is thought to be a possible factor of this phenomenon. (2) Early development of the secondary dentition directly caused this phenomenon. (3) We propose to add II B stage (exchange period of the incisors) in the Hellma's dental stage, if the "I" type will be more frequently found in Japanese children.

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The aim of this study was to examine the association between the presence of approximal caries and microbiological factors, the presence of interdental space and life style. Seventy-two children (mean age 4 years 4 months) who visited a private pediatric dental clinic in Okayama, Japan, were the subjects. The approximal surfaces between first and second upper primary molars were examined using the dental mirror, explorer and dental floss. Radiographical examination was also carried out. Questionnaires regarding snack habits and brushing habits were utilized. The plaque samples were taken from the approximal surfaces with dental floss and put into the Cariostat media. All of the samples were cultured in selective media for mutans streptococci (MS), streptococci and lactobacilli (LB). Colonies were enumerated and identified using biochemical tests. The results were as follows.
1) The approximal surfaces with caries shared significantly higher MS counts than surfaces without caries (p<0.01). Significant correlation was found between the number of MS and CSI (p<0.01).
2) The approximal surfaces with caries shared significantly higher SM levels than surfaces without caries (p<0.05). Significant correlation was found between SM levels and CSI (p<0.01).
3) The approximal surfaces with caries shared significantly higher LB counts than surfaces without caries (p<0.01). Significant conelation was found between the number of LB and CSI (p<0.01).
4) The Cariostat score at 48 hours correlated significantly to presence of approximal caries (p<0.05).
5) The status of interdental space correlated significantly to presence of approximal caries (p<0.01).
6) The aspects regarding brushing habits and caretaker during day time influenced the presence of approximal caries.

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This study was conducted with the caries activity test (Cariostat®) focussing on lactobacilli as well as mutans streptococci in 68 children (mean age 4 years 4 months) selected from patients at the pediatric private dental clinic in Okayama, Japan. The plaque samples were taken from the approximal surfaces between the first and second upper primary molars using dental floss and put into the Cariostat media. All of the samples were collected and cultured in selective media for mutans streptococci (MS), streptococci and lactobacilli(LB). Colonies were enumerated and identified using biochemical tests. The results were as follows.
1) A significant positive correlation was found between the Cariostat score at 24 hours and 48 hours and the MS count of the Cariostat medium.
2) A significant positive correlation was found between the Cariostat score at 24 hours and 48 hours and the SM levels of Cariostat medium.
3) A significant positive correlation was found between the Cariostat score at 24 hours and 48 hours and the lactobacilli count of the Cariostat medium.
4) Some of the samples were classified into two groups, one of them with a high Cariostat score at 24 and 48 hours and the other with a low Cariostat score at 24 and 48 hours, for the purpose of assessing the predictive ability of the Cariostat test at 24 hours and 48 hours for microbial counts.
The sensitivity and specificity were 0.80,0.91, respectively, for quantity of the MS counts; 0.90,0.84, for number of the SM levels; and 0.50,0.74 for the quantity of the lactobacilli counts.

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For prevention of nosocomical infection, hand disinfection is one of the most important factors. The objective of this study was to assess methods of hand disinfection. As some intresting findings were observed through this study, we would like to report on them in this paper.
Twenty pediatric dentists washed and disinfected their hands under the conditions of not wearing rubber gloves and wearing. After washing the hands in the running water, using a cake of soap, disinfected them with 75% povidone-iodone andscrubbing the paper towel, they pressed then five right fingers on Brain Heart Infuusion agars and the agars were incubated in aerobically atomosphereat 37°C, for 48 h. As results, under the condition of not wearing the rubber gloves, microorganisms could not be eliminated with any methods, but when wearing them some dentists were able to eliminate microorganisms properly by washing in running water. Some dentists who wore larger gloves were not able to eliminate microorganisms using a cake of soap but all of the dentists were able to eliminate them by disinfecting with 75% povidone iodone. Based on these results we must use well fitting rubber gloves and disinfect ourhands.

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The purpose of this study was to discuss the use of flowable composite resin on preventive resin restoration. A flowable composite resin (Palfique Estelite LV: Tokuyama) was filled in molars and sealed in premolars in vitro, with the use of a one step self-etching primer system (One-up Bond F: Tokuyama). As controls, Restorative Z-100 (3 M) was used as a conventional composite resin, and Single Bond (3 M) as a wet bonding system. The bonding ability, mainly with the enamel, was evaluated and compared, based on marginal leakage after the thermal cycling test.
Single Bond showed a significantly better marginal seal than One-up Bond F both in cavities and in fissures. There was no difference in marginal seal between Palfique Estelite LV and Restorative Z-100 in cavities, for both of the bonding systems. For fissures, One-up Bond F showed results inferior to those for cavities. The results indicate that One-up Bond F does not provide enough etching effect for enamel bonding especially in fissures (on sound enamel).
It was concluded that flowable composite resin can be applied to preventive resin restoration, and is recommended to be used with a wet bonding system which includes phosphoric acid etching (Single Bond), rather than a self-etching primer system (One-up Bond F).

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In this study,6-week-old Wistar rats, corresponding to the childhood period in humans, were used. They were divided into four groups as follows. The control group, low calcium diet (30%) group, low calcium diet with supplementary Unical® group, low calcium diet with supplementary Unical® and ipriflavone (IF) group, in order to observe the effect of calcium and IF on the enchondral ossification at the metaphysis of the tibia in rats. We obtained the results following.
1. Body weight
No significant difference was found between the experimental groups.
2. X-ray findings
Compared with the control group, the low calcium diet group showed that the trabeculae arranged sparsely. The low calcium diet with supplementary Unical® group showed more distinct surface and regular dense trabeculae than those in the low calcium diet group, but what was seen was not the same as in the control group. The low calcium diet with supplementary Unical® and IF showed similar results as with the control group.
3. Densitometry
The bone density of the corresponding trabecula was in the order of the low calcium diet with supplementary Unical® and IF group>control group>low calcium diet with supplementary Unical®group>low calcium diet group.
4. Histopathological findings
Compared with the control group, the low calcium diet group showed that the volume of hypertrophic chondrocyte increased. The calcified matrix around the chondrocyte, the primary spongy bone, and the number of ostocytes decreased, while the thickness of the trabecluae was thinner than the corresponding ones in the control group. It was found in the low calcium diet with supplementary Unical® group that there was increased hypertrophic chondrocytes and calcified matrix, and thicker trabecluae than that in the low calcium diet group. In the low calcium diet with supplementary Unical®a nd IF group, it was found that there were increased chondroclasts, active calcification of the intercellular matrix and newly formed bone from the enchondral ossification.
5. Hematological findings
No significant difference was noted in the serum electrolyte levels or the biochemical examination between the experimental groups. From the foregoing results, it was speculated that if the bone mass is fully attained in the school age period, even though bone loss is induced, the recovery of bone formation can be achieved by diet therapy with supplementary Unical® and IF.

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We made a clinico-statistical observation on the pediatric outpatients in our department during the past thirteen years. The results obtained were as follows: 1. The total number of pediatric outpatients was 1326. (males: 694, females: 632)2. The mean age of the pediatric outpatients was 7.7.3. According to classification based on clinical diagnosis of oral and maxillofacial surgical diseases, the number of anomaly cases totaled 244(31.9%), while there were 192 trauma(25.1%),89 inflammation(11.6%),77 temporomandibular joint disease(10.1%),73 cyst(9.6%),54 oral mucous disease (7.1%) and 35 tumor(4.6%) cases.

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The prevalence of dental caries of the deciduous teeth as well as the permanent teeth among children suffering from the Down syndrome has been reported to be lower than in normal children. However, the reason of the low incidence of caries in the Down syndrome is unclear. Although there are many reports about the low incidence of caries caused by factors related to the clinical findings, there are few reports about the biochemical characteristics of the teeth of patients with Down syndrome.
This study aimed at making a comparative analysis of the biochemical composition before and after the neonatal line on deciduous teeth with the Down syndrome patients and in normal children.
Mandibular deciduous central incisors without caries were extracted from 5 Down syndrome children(Ave. age 6.2±8.7) and 5 normal children(Ave. age 5.8±10.1) at a dental hospital in Nagoya, Japan.
Fluoride, phosphorus and magnesium concentrations from the enamel surface across the neonatal line before the dentine were analyzed using the abrasive micro-sampling technique, as described by Weatherell et al.
The differences in fluoride and the magnesium concentrations between children with the Down syndrome and the controls were evaluated using 2-way ANOVA and Scheffe tests.
The following results were obtained;
1) F concentration: Fluoride concentration was higher at the outermost enamel and decreasing towards the interior both in children with the Down syndrome and in normal children.
The average fluoride concentration of in children with the Down syndrome was lower than in normal children.
In particular, there was a statistical difference of 5% at the 40,80μm from the neonatal line in the enamel formed before birth, and 40μm from the neonatal line formed after birth
2) Mg concentration: There were no changes from the outermost enamel toward the interior of shown in both the children with the Down syndrome and in normal children.
The average magnesium concentration in children with the Down syndrome was higher than in normal children. However, all the fixed depths to be measured showed no significant differences.
The above results were not able to prove the low incidence of dental caries among children with the Down syndrome. It was concluded that the mineralization level of the enamel was lower in children with the Down syndrome than in the control teeth. It seems that the influence of mineralization on the enamel continued from before to after birth.

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The purpose of this study was to evaluate the correlations between three kinds of caries activity tests scores and caries prevalence. The caries activity tests used in this study were Cariostat (Cariostat^TM: Sankin), Rezazurin Disc test (RD test®S: h owa) and MSB broth (Mucount®: Showa). Caries activity tests and dental examination at one year intervals were performed on 71 patients ranging from Hellman's Dental Age II A to WA at the first caries activity tests and continued for 5 to 9years. The patients had all been examined for regular recall treatment at the Pediatric Dental Clinic of Nagasaki University School of Dentistry. The intervals of the recall visit of the patients were 3 to 6months. All of the dental examinations, caries activity tests and recall treatments were performed by one of the authors. Results at one year intervals of the items of the caries prevalence using the total number of the decayed teeth (d+D-tooth) except for Co, the total number of the decayed or filled teeth(df+DF-tooth), the ratio of the decayed or filled teeth (df+DF-ratio), and Caries Severity Index (CSI) and caries activity tests were classified according to the Dental Age. The correlation between the items of the caries prevalence and the scores on the caries activity tests of each one-year interval were analyzed (p<0.05). The correlation between the items of the caries prevalence and the scores on the caries activity tests for all patients at all tested times and the times when they first reached at the Dental Age II A to IVA were also analyzed. (p<0.05).
The following results were obtained.
1) For three of the caries activity tests, in comparing of the correlations between the items of the caries prevalence and the scores on the caries activity tests, Cariostat 48 hours scores showed significant positive correlations in many Dental Ages. The frequencies of the significant positive correlation for the RD test scores and Mucount scores were low.
2) The Cariostat 48 hours scores showed significant positive correlations between the items of the caries prevalence and the scores on the caries activity test with high frequency in the Dental Age IIIB, IIIC and IVA.
3) The caries activity test scores were not always high under the condition of high caries incidence and the results of the caries activity tests did not always reflect the caries prevalence.
4) Under the condition of low caries occurrence controlled by regular recall treatment, Cariostat 48hours values could reflect the caries prevalence.

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To analyze the growth of the glenoid fossa during the pediatric period, we measured the three dimensional reconstructed images using the helical CT. We selected 56 TM joints (28 cases) from the CT files of the department of Oral Radiology, Osaka Dental University and used them as materials. The CT of these patients (aged between 6 years and 12 years) was taken for the diagnosis with the exception of any influence of TMJ growth.
For these cases, we measured the distance following five points: the distance of the articular tubercle between each side, the distance of the postglenoid process between each side, the height of the inferior limited point of the articular tubercle and postglenoid process from FH plane and the height of superior limited point of the glenoid fossa. With these data, we compared the age and body weight factor of the patients.
The results were as follows:
1. The age factor had showed a greater relationship than the body weight factor concerning the distances of articular tubercle and postglenoid process between each side.
2. Concerning height, the age factor showed a greater correlation than the body weight factor. In addition this relationship was larger than that of the distance of the articular tubercle and postglenoid process.
3. Concerning the relationship of the height data with respect to age and body weight, the height of the articular tubercle showed a greater relationship than the height of the postglenoid process.
4. Each height data had showed a greater particular correlation to each other.

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This cephalometrical study was undertaken to look into morphological changes in the mandibular symphysis in patients with class I crowded malocclusion after treatment by means of edgewise appliances without premolar extraction. In addition, the effectiveness of this orthodontic treatment procedure was evaluated clinically.
The following is a summary of our findings.
1) The basal bone in the mandibular symphysis tilted lingually to a significantly large extent when cephalometrically observed after treatment.
2) The inclination of the basal bone had a negative correlation with the facial angle and a positive correlation with the occlusal plane angle.
3) The alveolar bone in the mandibular symphysis showed a significant labial inclination.
4) The inclination of the alveolar bone correlated positively to the labial inclination of the mandibular incisors.
5) The angle formed between the basal bone and the alveolar bone increased significantly.
6) The symphyseal thickness at point B decreased significantly.
7) The symphyseal height at points B, Id and Ll e also showed a significant increase.
8) The symphyseal height at points B and L I e correlated negatively to the increase in the occlusal plane angle respectively.
9) The increase in the symphyseal height at point Id correlated negatively to the labial inclination of the mandibular incisors.
The above-mentioned results suggested that morphological changes occur flexibly in the mandibular symphysis in the wake of mechanotherapy for Angle's class I crowding case by using the edgewise appliance without premolar extraction. Moreover, the area near point B in the mandibular symphysis appeared to play a pivotal role in bone remodeling. It was also suggested that this orthodontic treatment procedure we had used without removing premolars at the permanent dentition period should be taken into consideration in making plans for treating the crowding of teeth at the stage of

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We performed dental examinations on children in the kindergarten attached to Shanghai Teachers'University in Shanghai, China strating in 1996 using oral examination charts, intra-oral photographs, and dental casts obtained from 334 children aged 3 to 5 years in 1996 and 1999.
1. The caries incidence ratio was highest in children aged 3 and 4 years.
2. The caries incidence ratio of teeth and the mean per-child dft indices were slightly lower in 1999than in 1996.
3. The ratio of filled teeth rate was slightly higher in 1999 than in 1996.
4. The incidence of gingivitis was markedly lower in 1999 than in 1996.
5. Regarding malocclusion, the incidence of anterior cross-bite was slightly higher in 1999 than in 1996.
6. Regarding abnormal teeth, the incidence of black extrinsic tooth stain was slightly lower in 1999than in 1996.

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The purpose of this study was to assess the effectiveness of gingival health care and oral hygiene status in junior high school students. A survey was conducted with 355 junior high school students in 1994, and then again with 350 students of the same school in 1999, in Hiroshima, Japan. The Oral Rating Index (ORI) was used for assessing the periodontal status and the results were given to each student. An annual lecture regarding periodontal diseases was given to the students from 1992 to 1994, and a brochure has been provided since 1995, following completion of the first survey. The results of our study of these surveys are as follows.
1. The mean ORI score of the students in 1999 was significantly higher than in 1994 (p<0.001).
2. The mean ORI score of females was significantly higher than that of males at each grade level (p<0.001).
3. The differences in mean ORI scores between grades in both males and females in 1994 were not statistically significant, however, the scores tended to improve with a higher grade level in 1999.
In conclusion, the results of the present study indicate that an informational brochure on periodontal diseases was helpful in improving the periodontal condition of junior high school students.

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During the period of the growth and development of the dental arch, mesio-distal and labio-lingual changes in the maxillary deciduous and permanent canines were longitudinally studied in children. A longitudinal series of dental casts were obtained from 50 children at 2 month intervals from the completion of the deciduous dentition up to the stable period of the permanent dentition. The subjects were divided into two groups according to the arrangement of the permanent teeth those with a normal dental arch (30 children) and those with a crowded dental arch (20 children). The mesial and distal points of the deciduous and permanent canines, and the most prominent points on their labial and lingual contours were observed longitudinally.
The results indicated that measurement points of the deciduous canines of the normal and crowded groups move in the mesial and labial direction. When the amount of movement of the normal group was compared to those of the crowded group, the normal group showed a larger movement than the crowded group. Measurement points of the permanent canines of both groups moved in mesial and lingual direction. When the amount of movement of the normal group was compared to that of the crowded group, it was found that the normal group moved more mesially than the crowded group, and the crowded group moved more lingually than the normal group. When the distal point of the permanent canine was compared with the point of the deciduous canine at the exfoliation period in the normal dental arch group,20 bilateral canines did not show any apparent changes, but 40 canines had moved more than 1 mm in the mesial direction.
In the crowded dental arch group,19 bilateral canines did not show any apparent changes,17 canines had moved more than 1 mm in the mesial direction, and 4 canines had moved distally more than 1 mm. In the normal arch group, the permanent canine was in almost the same position or there was a more mesial position for the deciduous canine. In the crowded arch group, the permanent canine might have drifted distally.

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The purpose of present study was to observe longitudinally the changes of the consecutive curve of the incisal edges, tip and cusp tips (curve of Spee) in order to assess the relationship between the morphological changes of the curve and the occlusal development.
The materials of this study were serial dental casts of 44 children. The casts were obtained at twomonth intervals from early childhood to adolescence. To provide the physiological time scale for each subject, we selected the dental casts for measuring under the following 6 periods of development.
1. immediately after the completion of the deciduous dentition
2. just before the emergence of the mandibular permanent central incisor
3. at the attainment of intercuspation of the permanent first molars
4. at the exfoliation period of the second deciduous molars
5. at the attainment of intercuspation of the permanent second molars
6. at the stable period of the permanent dentition
We measured the height from the base of the dental casts to each landmark point such as the incisal edge, tip, and buccal cusp tip in order to observe the vertical changes of each point by means of digital vermier calipers.
The mean changes of the normal dentition group indicated that the curve of Spee gradually headed downwardly from the deciduous through the permanent dentition. The curve of Spee of 19 crowding cases showed changes similar to normal occlusion.
We compared the amount of changes during the deciduous dentition between the normal dentition group and the crowding group statistically. There were significant differences in the amount of changes in the buccal cusp tip of maxillary left first deciduous molar (X₁) which was larger in the normal group than in the crowding group. In contrast, there were significant differences in the amount of changes that the crowding group showed, with larger changes in the edge of the mandibular right deciduous lateral incisor (X₂), in the tip of the mandibular right deciduous cuspid (X₄), and in the distobuccal cusp tip of the mandibular right first deciduous molar (X₃) than that for the normal group. A discriminant analysis was performed to evaluate further the relationship between the changes in these points. This analysis showed that the changes of Xi the most closely related to identifying the crowding cases followed by X₂, X₄, and X₃. In combination, a discriminant function Z=0.1233 +1.2588 X₁-0.9483 X₂+ 0.0612 X₃- 0.7749 X₄ was introduced and these four changes explained 77.3% of t-he variation in the subjects.
These findings, in general, demonstrated the possibility that changes of these specific points may be related on to distinguish the crowding cases.

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It is said information exists in one's surroundings and “the meanings” and “the values” of surroundings have to be found in the ecological surroundings which is a basis of the affordance theory. We studied the process through which the child patients actively pick up “the meanings” and “the values” from sources in dental clinics and we interpreted them in order that we might predict their behavior and make child management easier. As one step toward this goal we recorded the behavior of children on the videotape when they proceeded to sit in a dental chair and leave it. In this paper, we present the results of the analysis as to how they sat and left, their position and the direction, where they looked and how they touched the chair with their legs and hands.
1. When children took their seats, children 3-4 years olds showed the tendency to climb, face toward the chair, while children 5-7 years old sat backward. When the seat was raised, younger children climbed from the footrest of the chair. When they alighted from the chair, almost all of the subjects, irrespective of age, straightened up and left with their backs to the chair.
2. Approaching the dental chair, most child subjects turned their eyes to the dental chair as they got closer to it.
3. As for the way their legs touched the dental chair, most children touched with their right leg when they climbed face toward the chair and with their left leg when they sat backward.
4. As for the way their hands touched the dental chair,30 to 40% children touched while they were approaching the dental chair.
From the above, it was found that child patients were choosing the best way to get on the dental chair according to their age and ability. At that time it was suggested that not only visual sensation but also tactile sensation was performed as a way to collect information for cognition.

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The incidence of serious dental caries has recently been on the decline. In step with this tendency, it has become a common practice for dentists to promote recalcification or arrest the development of the decay process in incipient cases, and place their patients under doctor-monitored observation instead of choosing restrative treatment right away. The situation is such that conventional mass screenings for dental caries alone are inadequate. It is now imperative to work on such dental examination programs that lay more emphasis on the importance of personal oral health maintenance and provide the public with up-to-date information on tooth decay preventing methods. Our department has conducted studies in order to formulate a new dental caries index based on which we could offer instruction in oral hygiene measures as well as information on caries prevention measures. In this paper, we will report the results of an 8-year follow-up study of caries incidence in primary and junior high school students in a rural community, Niigata Prefecture, by using a criteria we proposed earlier. The criteria is based on the ratio of the number of untreated teeth in the year X plus 1 to the total number of healthy and treated teeth in the year X after eruption. The following is a brief summary of our findings.
1. The untreated tooth ratio came to less than 1% in the incisor-premolar tooth group.
2. The untreated tooth ratio in the molar group at the maximum worked out at 8.1% for the maxillary first molars,4.2% for the maxillary second molars,12.4% for the mandibular first molars and 5.2%for the mandibular second molars.
3. The untreated tooth ratio in the molar group as a whole peaked one year after eruption of the teeth, kept declining until three years after eruption and remained unchanged thereafter.
4. The ratio of the number of untreated teeth compared to the number of healthy teeth was higher than the ratio from the number of treated tooth ratio-by around 10% after eruption. The untreated tooth ratio compared to the treated tooth reached a maximum of 6.3%. A significant difference was observed in some of the samples.
These findings suggested that the untreated tooth ratio can be useful as a new index for assessing the caries incidence.

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To gain an insight into the way adults visually observe the movements of other people, including children, we videotaped the movements of an individual who started walking from a stationary state and the movements of a pattern of luminous dots likened to the figure of a man, a woman and a child. By means of a Visicon Eye-camera, the eye movements of adult subjects reacting to these stimuli were measured and analyzed. A summary of our findings is as follows.
1. In terms of the total frequency of fixation point, total duration of fixation point, average reaction time to reach the initial fixation point, frequency and duration of fixation onto a human object, luminous dots and background and frequencies of fixation on the upper and lower parts of each image we found that there were not any clear differences in eye movement whether the objects were plain human figures or a pattern of luminous dots.
2. From the patterns of the occurrence of fixation points when the object, whether their human or luminous dots, is moving, it was made clear that many of the subjects set eyes on the object immediately after it started moving and followed the moving object.
3. Based on the reply to the question about the image comprised of luminous dots, all of the subjects who were seeing the luminous dots object or its background were not able to regard it as human when the dotted image was immobile while they were able to regard it as human when the object was moving.
From the above, we concluded that there was some difference in the adults' recognition of the human object and the luminous dots object when they stood still. This had nothing to do with the eye movements. When the objects were moving, the subjects recognized the human objects and the luminous dots to be human using gazing eye movement and pursuit eye movement. These results could be very helpful in understanding the movement of the patients, whether grown-up or infant, in dental clinics.

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To determine the oral status of 300 children treated at our hospital, their parents were asked to complete a questionnaire. The items surveyed included: 1. presence of halitosis,2. brushing habits,3. intra-oral condition,4. life style,5. oral habits,6. general health,7. smoking in the home. In addition,96 subjects were selected at random from those surveyed and the quantity of intra-oral ammonia was measured by a halitosis test system (Atein^TM).
As a result of the survey the subjects were categorized into two groups; Group A, children with noticeable halitosis (137,45.7%) and Group B, children without halitosis (163). In Group A, parents most frequently responded that halitosis was noticeable upon their child waking up (66.0%). The most frequent remedies for morning halitosis were not to do anything (37.6%) or to have them brush their teeth (36.8%). Using the X2-test between each survey item in Groups A and B, the following items differed significantly between the two groups: gingival bleeding when brushing (p<0.05), gingival pain (p<0.005), fur coating of the tongue (p<0.001), and smoking in the home (p<0.001). The halitosis test showed that the average concentrations of ammonia differed significantly between Groups A and B, at 25.5±173 ppm and 18.7±16.1 ppm, respectively (p<0.05; Mann-Whitney Utest).
In conclusion, it was suggested that we need more studies and clinical approaches concerning halitosis in children.

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The present study compares the effect on the swallowing threshold of mastication time, number of masticatory strokes, water content of the food bolus, degree of food pulverization and bolus texture between normal salivary flow and suppressed flow.
Six adults with a normal complement of teeth were selected. Cooked (steamed) rice was used as the chewing material and hyposalivation was induced with 0.5 mg of atropine sulfate. Each subject chewed and swallowed 5 g of boiled rice and the mastication time and number of masticatory strokes were determined. Mastication rhythm was then calculated. After chewing 5 g of boiled rice in time with a metronome, the subjects expectorated the food bolus. The water content of the bolus was measured using a freeze dry method. The bolus was then sieved with 10 mesh screen to measure the degree of food pulverization. The Texture Analyzer® was used for texture measurement and the Texture Expert® for data analysis. Texture was measured and analyzed using the double-bite test method. One hundred and twenty minutes after administration of atropine sulfate, to confirm that the secretion of saliva was suppressed, each subject chewed 3 g of gum base for one minute. Once suppression had been confirmed, the same test used for normal salivary secretion was repeated six times and the same items were analyzed. The results of the analyses before and after saliva suppression were compared using Student's t-test.
Significant differences in mastication time, the number of strokes, bolus water content and degree of food pulverization were found, but no significant differences in adhesiveness was found in any of the subjects when the salivary flow rate was reduced. These findings suggested that degree of food pulverization and bolus adhesion is affected by food surface moisture and may affect the swallowing threshold.

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The purpose of this study was to examine the developmental changes of the maxillary and mandibular base length in crowded dentition. The subjects were divided into four groups depending on their dentition at Hellman's dental stage
IVA: 1) males with normal dentition (n=5),2) males with crowded dentition (n=5),3) females with normal dentition (n=5) and 4) females with crowded dentition (n=5). The materials used in this study were lateral cephalometric X rays which were taken longitudinally from ages II C to IVA.
The results obtained were as follows;
(1) A'-PNS for both males and females with crowded dentition were slightly smaller than those for males and females with normal dentition at age II C, while the difference both was obvious from ages III A to IVA in that of males and females with crowded dentition were smaller than those for males and females with normal dentition.
(2) ABR'-B' for both males and females with crowded dentition were similar to those for males and females with normal dentition at age II C, while the difference both was obvious from ages IIIA to IV A in that males and females with crowded dentition were smaller than those for males and females with normal dentition.
The maxillary and mandibular base length of crowded dentition was smaller than that of normal dentition from ages III A to IVA, while the maxillary and mandibular base length of crowded dentition was similar to normal dentition at age II C.

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Purpose: It has been suggested that the ideal occlusion would contribute to dental caries prevention, and that malocclusion would increase susceptibility to dental caries. In Shanghai, as a type of malocclusion, deep overbite of the deciduous dentition was observed at a high rate (44.5%). In this study, we examined the prevalence of the dental caries of the deciduous dentition in relationship to normal occlusion and deep overbite.
Methods: Four hundred and fifty-one Chinese children (232 boys and 219 girls, aged 2-6 years old, residents of Shanghai) participated in this study. Oral examination was carried out based on the WHO criteria.
Results: The dft of normal occlusion was 3.0 and the dfs was 5.7. On the other hand, group of deep overbite showed low dft and dfs numbers,2.3, and 4.1 respectively. We divided the deciduous dentition into the anterior teeth region and the posterior teeth region and then compared each of them with the normal occlusion group and deep overbite group.
As a result of the statistical comparison, the dft and the dfs of the deep overbite group were clearly lower in the posterior region (Student's t-test, p<0.05).

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Disturbances in dental development were reported in an 8-year-8-month-old girl with neuroblastoma who had been treated with chemotherapy at an early age.
The patient was diagnosed at the age of 2 years with neuroblastoma (Stage IV A). She was treated with a high dose of chemotherapy between 2-years and 2-years-9-months of age. After chemotherapy, she underwent a surgical resection of the tumor and an autologous bone marrow transplantation. She never underwent a total body irradiation, however.
All of the first premolars were reduced to the microdontia although the other erupted teeth exhibited normal crown size. Panoramic and dental radiographs, taken at the age of 8 years and 8 months, showed other multiple teeth anomalies. All of the second premolars and the lower right second molar were absent. The incisors, canines, first premolars and first molars exhibited short tapered roots and premature apical closure.
These findings indicate that a high dose of chemotherapy may result in a higher prevalence of various malformation of the teeth.

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Two child patients with partial anodontia received follow-up dental care for the functional as well as esthetical improvement involving insertion of the partial dentures at the Pediatric Dental Clinic of the Tsurumi University Dental Hospital.
Since the patients of partial anodontia exhibit a naturally small denture pattern as well as reduced alveolar growth, dental care must be focused on controlling the height of the occlusion for producing the partial or over denture for them. For this purpose, we utilized angle and linear analyses of the Xray cephalograms of the patients and these date were compared with the average values of the normal cases of the same age for determining proper height of the bite plate or dentures produced.
A 7-year-9 month old girl (case 1) showed thirteen congenitally missing teeth. Her anterior crossbite was corrected by using an activator, and the partial dentures were inserted bimaxillary at the age of 10 years-11 months.
A 10-year-old boy (case 2) showed eighteen congenitally missing teeth. The over dentures were inserted bimaxillary at the age of 10 years-9 months. Frenectomy of the upper labial frenum and closing of medial diastema were performed, and microdontia of _??__??w__e?r?e_ a lso improved with the resin jacket crowns.
These two cases were followed clinically up to respective 14 years of age and 13 years-5 months of age.

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