This study was carried out to clearly establish a relationship between development and adaptability to recumbent position brushing in preschool children. We investigated the behavior of 98 normal children, under 6 years og age, while being brushed by their mothers who laid the children on their backs. Their developmental ages were estimated by Enjoji's Infant Analytic Development Test.
The results were as follows:
1.89.8% of the subjects' mothers brushed their children's teeth more than once per day.
2. The rate of the subjects observed displaying unsuitable behavior by interfering in the brushing with their hands was 20.4%. The rate of subjects who interfered by moving their bodies or heads was 17.3%, by closing their mouths,15.3%, and by biting the toothbrush or crying was 13.3%.
3.78.6% of the children readily adapted to recumbent position brushing, while 21.4% of the children were found to be unsuitable for the method.
4.12.2% of the mothers held their children down while brushing their teeth. However, even with the occurrence of unsuitable behavior,9.2% of the mothers did not restrain their children.
5. A significant relationship was observed between adaptability to the recumbent position brushing method and the developmental age of the subjects.
6. The developmental age (determined by Enjoi's Infant Analytic Developmental Test) at which the children were able to adapt to the method was about 2 years and 6 months.
7. It became clear to us that children over 2 years and 6 months developmental age will readily adapt to the recumbent position brushing method.

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The purpose of this study was to investigate the influence of the etching times on the adhesion of the resin on the primary ground enamel.
Fifty extracted and frozen bovine mandibuler primary incisors were used. The etchant used in this study was 37% phospholic acid gel and the etching times were 0,10,20,30 and 60 seconds. All of the specimens were washed with an air water spray after etching. The bonding agent and composite resin used in this study were Dual Cured Scotch Bond and Silux (3M Co. ). Shear bond strengths on the ground enamel were measured. After the shear bond strength test, all the test surfaces of the enamel and resin specimens were observed using the SEM. The results of this study were compared with the previous results using Photo Bond and Photo Clearifil A (Kurarey Co. ).
1) The etching time which showed the highest bond strength was 20 seconds (76.77±12.99 Mpa).
2) When the enamel was etched with all of the etching times, the bond strength were significantly higher than that of the enamel without etching (p<0.01).
3) In the etched groups, there was no significant difference among the bond strengths with all of the etching times categories.
4) In the etched groups, the longer the etching times, the lower the standard deviations were.
5) On the enamel specimens after the shear bond strength test, the frequency of the resin tags fractured inside of the enamel prisms was higher in the group which showed a lower bond strength.
6) For the same etching times, significant difference between the bond strengths of Silux and those of Photo Clearfil A was obtained only with the 20 seconds of etching time (p<0.01) and the bond strength of Silux was higher.

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The nature and the type of fillers in composite resin are multifarious. The purpose of this study is to determine the methods of distinguishing the fillers. After the treatments stated below, the surface of polymerized composite resins was observed by means of SEM.
1) The air-inhibited layer on the surface of composite resins was removed by acetone. Observations showed inorganic filler and prepolymerized filler protrusions on the resin surface; submicron filler and microfiller were noticeable.
2) Following the treatment in #1, composite reisns were soaked in fluoric acid in order to dissolve any inorganic filler substance. Results displayed pores in the area of the dissolved inorganic filler while a microporous surface was observed on the prepolymerized filler. By this process the type of prepolymerized filler can be classified according to the forms of the contained inorganic filler.
3) The surface of the composite resin was polished with #1200 sand paper. This method shows the difference between the fillers and the matrix resin; however, a clear distinction of the type of filler is difficult to determine.
4) After treatment in #3, the specimen was soaked in fluoric acid. Similar results as treatment in #2 were found; however, microstructure of the syntered filler was easily observed. It is possible to distinguish the filler types of the composite resins by the above mentioned treatments.

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The prevalence of dental caries in first permanent molars was measured in 220 children who have been under regular dental care at the Pediatric Dental Clinic, Tohoku University School of Dentistry. While the caries prevalence rate of first permanent molars reached approx.50 % five years after the eruption, the number of filled surfaces per restored tooth was less than 2.0. The caries prevalence of the permanent mandibular first molars was significantly higher than the caries prevalence of the permanent maxillary first molars. However, the occlusal surface showed no significant differences between the maxillary and mandibular molars. While comparing the female to male group, the caries prevalence rate was significantly higher and the peak of caries occurrence on every surface was earlier in the females. Pit and fissure sealants were applied to approx.75 % of first permanent molars and the occlusal caries were reduced as a result of sealing. When sealants were applied to the teeth diagnosed as C₁,50 % were restored due to development of caries. This was a significantly higher rate than that applied to sound teeth. Our study indicates that most of the occlusal caries occured in the earlier stage of 1-2 years after the eruption, before sealants were applied. The buccal fissure of the lower molars and the occlusal fissures both showed high caries prevalence. It was suggested that prevention of fissure caries immediately following eruption until the sealant is applied is an important issue in our present dental care system.

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The collision-and-abrasion test was performed to reproduce the change of the surface structures of posterior composite resins by the stress of mastication and occlusion. Also the effect of the stress on wear and marginal fracture of composites was estimated qualitatively and quantitatively between the cavities with round bevel, straight bevel and butt joint.
Extracted human posterior teeth were used as materials, and round or straight bevels were prepared along the margin of the standaraized cavities using the bevel-preparing burs which had been designed by us.
Light cured posterior composite resin (Occlusin/ICI Co. ) was used as the restoration material. Also the surface structures were examined before and after the collision-and-abrasion test with the scanning electron microscope and laser measuring device for the surface morphology.
The following results were obtained.
1. The collision-and-abrasion test with use of the slurry of polymethyl methacrylate (PMMA) powder as abrasive showed better reproducing ability of the in vivo change of the posterior composite restrations.
2. The collision stress was found to be one of the main causes for the wear and marginal fracture of composites.
3. It was found that the measurement for wear and marginal fracture of restorations could be performed three-demensionally with high precision and in shorter time by using a laser device.
4. Marginal fracture resistance of composite resins is influenced by the adhesion with tooth structure and the marginal thickness. Therefore, the best marginal shape for posterior composite restoration is the round bevel.

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Three-week-old male rats of the Wistar strain given standard formed food (MF formed food) were grouped as controls. Those given calcium-deficient food for three weeks and then standard formed food after experimental osteoporosis induced in the rats were grouped as the experimental group. Experimental periods were for 4 and 6 weeks and the effect of the food on osteoporosis was investigated.
The results were as follows:
1. Bone density of the alveolar bone showed significantly lower values for the experimental group than for the controls.
2. In comparison of relative Ca ratios (Ca/[Ca]c) and of P ratios (P/[P]c) on an X-ray microanalyzer, the controls showed higher values each week than the experimental group.
3. Compressive strength of the mandible in the experimental group decreased compared with the controls.

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As Colchicine is an inhibitor of the function of microtubles, administration of it causes abnormal amelogenesis in the teeth of experimental animals. The purposes of this study were to characterize the defective rat enamel which was formed after a single administration of colchicine, and to examine the effects of Nd: YAG laser with continuous wave on the acid resistance of the defective enamel.
The following results were obtained:
1) On about the 10th day after a single subcutaneous injection of colchicine with a dose of 1.5 mg/kg of body weight, the defective enamel was found on the incisor as white bands with rough surface.
2) The defective enamel had less resistance to the acid demineralization than that of normal enamel.
3) After irradiation of Nd: YAG laser with continuous wave, the defective enamel surface became smooth and the small defects on the enamel surface disappeared.
4) After irradiation of Nd: YAG laser, the resistant level of the defective enamel to the acid demineralization increased up to that of normal enamel. The results suggest that Nd: YAG laser irradiation on human teeth with hypomineralized enamel may be effective for the prevention of dental caries.

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The first aim of this study was to investigate the amount of fluoride released from fluoride releasing resin for the denture base (F-resin). The second aim of this study was to determine the uptake of fluoride with bovine enamel, which was immersed in distilled water for 90 days in contact with F-resin.
The results obtained were as follows.
1) The amount of fluoride released from F-resin decreased gradually. From the 10th day of immersion, the amount of fluoride released was almost constant. The fluoride could be detected on the 90th day.
2) The uptake of fluoride from F-resin was great both on the surface and the subsurface enamel.
3) The uptake of fluoride from F-resin was almost proportional to the immersing time.

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The present study was designed to discuss the reproducibility and the clinical usage of the T-Scan system in children.
A plastic model of a normal permanent dentition was used for the study. The model was pressed on the sensor of the T-Scan system in maximum intercuspation under various assigned pressures (10,20,30,40 and 50 kg) which were controlled by a press machine (Auto Graph AG-5000C). The pressings were made under following conditions, such as 1) the sensor handle was fixed,2) the sensor handle was free and 3) the sensor handle was free but the maxilla arch form was marked on the sensor by the silicone impressional material. The total number of tooth contacts were counted and sagittal and the vertical distance from midline to the tooth contacts were measured.
The results obtained in the present study are summarized as follows;
1) The number of tooth contacts became stable, when the pressing sensor was exercised several times.
2) The more pressure raised on the sensor, the more the number of tooth contacts increased, and the more the coefficient of variation tended to decline.
3) The arch model displayed on the T-Scan system was not exactly represented in the actual dental arch.
4) Due to the marking by silicone impressional material on the sensor, the reproducibility of the T-Scan system was further improved.

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The correlation between the behavioral and emotional reactions before dental treatment and the adaptability to dental treatment was evaluated in 84 three-tosixyear old children. Also the physical behavior of the children, the verbal reaction of the children and the speaking of dentists to the children during treatment were investigated among 13 cooperative and 13 uncooperative three-to-six-year old children.
Dental treatment was conducted with tooth brushing, surface anesthesia, infiltration anesthesia, rubber dam application, cavity preparation with air turbine, cavity preparation with electric motor and composite resin filling.
The results are summarized as follows:
1. There was a significant correlation between twelve of the twenty behavioral and emotional reactions before treatment and the adaptability to dental treatment.
2. The children who showed an uncooperative behavior to dental treatment showed a higher score of physical behavior during each treatment than the children who showed a cooperative behavior to dental treatment.
3. The score of physical behavior increased as the treatment progressed from tooth brushing to infiltration anesthesia. Among the children who showed cooperative behavior, the score showed a peak at the infiltration of anesthesia and then decreased. On the other hand, the children who showed uncooperative behavior continued showing a high score.
4. The uncooperative children showed a higher frequency of verbal reaction and crying than the cooperative children.
5. The frequency of speaking of the dentist to the uncooperative children was one and a half times as much as to the cooperative children. More than sixty percent were “instructions” and “explanations” to both of the cooperative and uncooperative children. “Praise” was used more to the cooperative children, and “count 10” and “encourage” were used more to the uncooperative children.

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The purpose of this study was to determine the characteristics and longitudinal changes of the arch morphology and occulusion of the deciduous open bite cases.
The materials used in this study were the serial plaster casts of 40 Japanese children with deciduous open bite, and they were measured with the three dimentional system. The following results were obtained:
1. The form of dental arch with open bite in the early primary dentition changed remarkably in the maxilla but little in the mandible. In children with open bite, the maxillary intercanine distance was narrower, the maxillary arch length was longer, the palatal height of the front area was higher, but the back one was lower, and the upper central primary incisors were located more forward and upward higher than in children without open bite.
2. In the late primary dentition, the dental arch shape in the spontaneous closure group showed little difference from the control group. However the deciduous upper central incisors of the spontaneous closure group were very remarkably inclined to the palatal side, and the vertical over-jet was larger than that in the control group. The larger the horizontal over-jets were in the early deciduous dentition, the larger the vertical over-jet changed in the late deciduous dentition.
3. In the spontaneous closure group, the point of the dental arch showed a regular changing aspect, in which place marked variation was recognized in the early deciduous dentition as compared with the control group. Because of spontaneous closure, the dental arch shape approached the one of control group rapidly.
4. The result of multivariate analysis indicate that not only discontinuance of thumb-sucking but also many variables of the dental arch shape and occlusal condition may induce spontaneous closure of the open bite within the deciduous dentition term.

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We conducted a behavioral scientific research from the point of view of dental fear prevention. This time, the writers carried out the surveys with the goal of understanding and making clear the realities concerning dental anxiety in the four countries: Japan, Indonesia, Brazil and Argentina. The subjects were 728 dental students from the four countries, and the surveys consisted of 25 multiple choice questions which were divided into three major areas. The first area consisted of preliminary questions such as chief complaints and treatment experiences, the second area dealt with the reactions and physical responses on receiving dental treatment and the third area was on the different levels of anxiety shown during treatment expressed through feelings and reactions. We concluded as follows:
1. In Japan,77% of the subjects reported having at least a little fear and this percentage was higher than those of other countries (45-65%). But in all countries,4-7 % of subjects reported having extreme dental fear.
2. In Japan and Brazil, women reported the higher fear than men. In Indonesia and Argentina, these results were the opposite.
3. According to canonical correlation analysis, a significant correlation between the level of physical reactions and the degree of dental anxiety was found in all countries.
4. In the high fear group, dental anxiety increased by psychological stress before treatment and the expressions of physical reactions were stronger than in the low fear group.

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This study was designed to investigate the effect of adhesive composite resin (Clearfil SC Bond) on dental pulp and the effect of calcium hydroxide base (Dycal)on the protection of the pulp, using 66 deciduous teeth of young dogs.
After forming a cavity (class 5) on the labial aspect in each tooth, the teeth were divided by the modes of plugging into 4 groups; stopping alone (Group S), stopping and capping with Dycal (Group D+S), capping with Dycal and resin (Group D+R) and capping with resin alone (Group R). After decalcification, the specimen was embedded in celloidin, sliced into thin sections and stained with hematoxylin and eosin for histopathological examination.
Histological changes were examined at 3 days,1 week,2 weeks and 4 weeks. The following are the results obtained.
1. In Group S, slight histological changes were observed at 3 days and 1 week. However, the changes began to diminish after the 2nd week and disappeared in the 4th week.
2. In Group R, the severest histological changes persisted throughout the course of observation. The changes were not diminished even in the 4th week. Thus, the resin seemed to exert a strong and long-lasting stimulative effect against the pulp.
3. In Group D+S and D+R, the histological changes were more serve at 3 days and 1 week compared to those found in Group S, but these were diminished after the 2nd week. This seemed to suggest that the pulp was stimulated to a certain degree by Dycal but also, Dycal protected the pulp from stimulation of the resin.
4. Capping of the pulp seemed necessary in vital teeth with resin restoration.

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To measure the masticatory force used for everyday foods it is desirable to base the measurements on one mouthful of food. However, one mouthful of food changes in size and hardness. The purpose of this study is to establish a formula for estimating a correlation between the amount and force of mastication, active potencials and their integrated values, and the concerned material's size and hardness no matter they are same or unified. It is possible to measure the amount of mastication for normal foods without recording electromyographically.
The effective method for recording the hardness of the jelly is the application of needle plunger. The thickness divided by the hardness and multiphying the value with the volume of the material, an estimated formula is thereby establish to correlate with the integrated values of mastication.

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An epidemiological investigation of dental caries was undertaken during the period of 1987-1989 with all children of nursery school, kindergarten, elementary and junior high school age in the town of Fuji, Saga prefecture which is a mountain villate, experiencing little movement of the population. From this investigation the following results were obtained.
1. Although the number of the children in each age group who had dental caries in deciduous and permanent teeth appeared to have decreased compared with 1987 and 1989, the dental caries prevalence in the children still remained high.
2. It appeared that it was important to give dental health education during the stage of immature young permanent teeth since there was prior to evidence of high dental caries in this stage.
3. The following was suggested for the improvement of caries experienced in immature young permanent teeth in the school in Fuji: (1) no stock of soft drincks in the refreigerator, (2) guardian's strict supervision of their children concerning snacks and, (3) acquiring of the habit of brushing during infancy and preschool years with parental assistance.

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Children with congenital heart disease (CHD) are prone to present abrupt changes in cardiovascular functions which cause hypoxic spells or accute heart failure, so that oxygen monitoring during dental treatment is of great importance in cyanotic CHD patients.
Monitoring of arterial oxygen saturation (SpO₂) by pulse oximetry has several advantages, including rapid response time, freedom from skin injury, self-calibration and continuous readout of the SpO₂ value. In these studies, SpO₂ was measured in 68 pediatric patients (55 were CHD children and 13 were normal children) during dental treatment at the Pediatric Dentistry, Hokkaido University Dental Hospital.
In all of the normal patients, SpO₂ did not desaturate less than 95%. On the other hand, SpO₂ ranged from 56% to 98% in CHD patients, and in 22 % (n=12) of these, SpO₂ desaturated below 80%. All of the SpO2<80% patients had been diagnosed as cyanotic CHD.
Classification of CHD cases (n =144, the total number of measurements) on the pattern of the SpO₂ variation revealed that in 11 % (n=16) of the CHD cases, SpO₂ decreased during dental treatment. Twelve of these 16 cases could not readily accept dental treatment. We suggest that behavior management is the most important factor in CHD patients for keeping SpO₂ stable.
Motion artifact of the SpO₂ value, which was easily evoked when a patient bent his elbow or shook his finger, often made the pulse oximetry useless. In our studies, the SpO₂ value sometimes became inaccurate in fearful infants or handicapped patients. Pulse waveform displayed on the front panel of pulse oximetry was useful to identify the motion artifact.
We conclude that pulse oximetry is an appropriate apparatus for continuous arterial oxygen monitoring in pediatric patients during dental treatment as far as motion artifact is effectively eliminated.

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The subjects were a total of 60 children, of which 30 were kindergarteners, and 30 were school age children.
Changes in internal behavior were observed when the subjects were stimulated by only visual stimulation (V), only audio stumulation (A) and audio-visual stimulation (AV) of the crying of other child patients for 20 seconds each.
The change ratios of the 3 stimuli were analyzed with respect to the plethysmogram (PL), the respiration curve (RC) and the galvanic skin reflex (GSR).
The internal changes to the 3 stimuli of the crying were compared with difference in stimulus, age difference, sex difference, the difference of dental anxiety.
1) The change ratios decreased in the following order, AV>A>V on PL and RC. There were significant differences between V and A, also V and AV on PL and GSR. Based on the standardized score, the score decreased in the following order, AV>A>V, and there were significant differences between V and A, also V and AV.
2) Comparing age groups, kindergarteners showed larger change ratios than school age children for A and AV by GSR. Based on the standardized score, there were no significant age difference for each stimulation.
3) Comparing sex groups, there was a significant difference for A by PL. According to the standardized score, there was no significant sex difference for each stimulation.
4) There was no significant difference for each stimulation by the dental anxiety degree of the mother.

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This research concerns the reasons for having the mother located beside the dental chair and the influence on the dental staff by the patient's mother.
The subjects were a total of 390 persons, of which 100 children,100 mothers,100 doctors and 90 assistants.
A total of 20 items consisting of 10 items from the psychological test and 10items from the dental charts.
Discriminant analysis was carried out according to the second class of Hayashi's quantifying theory concerning the entrance into the dental office or non-entrance chosen as an external criterion.
The mothers answered questions on the psychological test about the psychological distance between the mother and the child. They also answered the questionnaires about their psychological process.
The doctors and assistants answered concerning to “manifest anxiety scale”and questionnaires about their psychological process. The results are summarized as follows:
1. The ratio of the distinctive efficiency of external criteria to the entrance or nonentrance was found to have a high correlative coefficient,0.70. When the factors mentioned above are ranked according to the external criteria the order is as follows: “treatment expierience of the child”, “adaptation degree to the treatment of the child”, “birth order of the child”, “clinical experience of the doctor”, “the child's age”.
2. The psychological distance of “the mother waiting out of the dental office” is longer than the distance of “the mother in the dental office”.
3. The mother's presence in the dental office had some psychological influence on the doctor and the assistant.

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There were a total of 100 subjects, of which 50 were children and 50 were mothers. The first time, the doctor lends the child the fairy tale book. The second time, the child is treated under the audio-analgesia with the same fairy tale book and the child borrows on other fairy tale book. The third time, the child is also treated under the audio-analgesia. The child, the mother and the doctor answered the questionaires.
Changes in internal behavior were observed by polygraph system. The subjects comprised a total 13 children (4 to 6 years), of which 6 were males and 7 were females. The first time, the emotional reactions were observed when the subjects were stimulated by the engine, the turbine and the crying for 10 seconds each. The Second and third time, the emotional reactions were also observed under the audioanalgesia. The change ratios were analyzed with respect to Plethysmogram, Respiration Curve and Galvanic Skin Reflex.
The results are summarized as follows:
1.91.8% of the parents answered “I would like my children to be treated under the audio-analgesia using fairy tales.”
2.73.5% (2nd time) and 80% (3rd time) of the children answered “The treatment has been pleasent.”
3.61.2% (2nd time) and 64% (3rd time) of the doctors answered “The anxiety and fear was reduced by the approach.”
4. With the engine stimulation, the emotional reaction derceased in the order, of the 1st time
3rd time
2nd time. There were significant differences between the 1st time and the 2nd time, and also between the 1st time and the 3rd time.
5. With the turbine stimulation, the emotional reaction decreased in the order, of the 1st time
2nd time
3rd time. There was no sigpificant difference.
6. With the cyring stimulation, the emotional reaction decreased in the order, of the 1st time
2nd time
3rd time. There were significant differences between the 1st time and the 3rd time.

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The purpose of this study was to investigate the etiology and characteristics of the ectopic eruption of first permanent molars. The subjects were 35 cases (27 maxilla and 8 mandible) with ectopically erupted permanent first molars, which were recognized in 24 out-patients (10 boys and 14 girls) visiting Tohoku University, Dental Hospital. The materials used for the analysis were dental casts, X-ray lateral cephalograms and panoramic radiographs, and both materials of the ectopic and normal groups were compared.
The results were as follows,
1) There were no significant differences statiscally between the mesio-distal crown diameters of the maxillary permanent first molar, central and lateral inciser, and all deciduous teeth in ectopic group and their mean values in Ono's and Otsubo's studies.
2) There were no significant differences as compared to all parts of the size of the dental arch in ectopic sides with those in the normal sides of same individuals at IIA and IIC of Hellman's developmental stage in dentition.
3) When the sizes of the dental arch in the ectopic group were compared with those of the normal group, the former were smaller at the distance between the mid-point and the canine mesial surface(Fig.1-(4)), the ridge of the posterior region of the basal arch and most distal point of the primary second molar (Fig.1-(6))at the Hellman's dental age IIA, while the canine distance to the midline(Fig.1-(1)), the dental arch perimeter from mid-point to the distal surface of primary second molar(Fig.1-(4)+(5)), and the distance between the canine and primary second molar, div. X(Fig.1-(7))at Hellman's dental age of IIC were significantly smaller than the latter.
4) Regarding the comparison of the value of the changes in dental arch size between the ectopic group and the normal group from Hellman's dental age of IIA to IIC, the distance between the canine and primary second molar, div. X (Fig.1-(7))decreased markedly and the distance between the ridge of the posterior region of the basal arch and the most distal point of the primary second molar(Fig.1-(6))increased.
5) Results of the analysis of X-ray lateral cephalograms showed that the angle of eruption of first molars in the ectopic group was significantly smaller compared with normal group.
6) According to the cluster analysis on the calcification of tooth germ using panoramic radiographs, similarity among all of the samples was lacking in the ectopic group, especially congenital missing of the second molars and second premolars in the ectopic side and the delayed calcification of the ectopically erupted teeth were found in maxilla.

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It has been reported by BALAKRSHANN and ASHTON that about 20-30bands of human salivary protein separated by polyacrylamide gel electrophoresis (PH 8.0) were detected by staining with Coomassie brilliant blue R. Employing the same method, MATSUSHIMA discovered five main regions (I~V) in mouse salivary protein (Msp) separated by poly-acrylamide gel electrophoresis (PH 8.0). He also discovered distinctive features of biochemical genetic markers among each of the five regions. In this experimental study, we investigated biochemical genetic markers of Msp of C3H/HeJ, BALB/c, BALB/k and NOD/shi strains. The following were the results of the present study.
1) The results of C3H/HeJ and BALB/c mice were in accord with those of MATSUSHIMA's.
2) The BALB/k mouse showed the same results as the BALB/c the difference in sex of Msp-1 seemed to have no relation to H-2 complex.
3) With the NOD/she strain, Msp-3 showed the b-type, Msp-2 the a-type, Msp-1the o-type showed no difference based on sex, that is to say, F-type in both male and female. Amylase-1 showed the b-type.

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Children with blood diseases do not infrequently visit the dental clinics. Therefore, it is important to recognize the actual condition of blood diseases in association with the oral treatment of patients. During the period from Sept.1979 to Jun.1989,68 patients who had blood diseases visited the Pedodontic Clinic of Niigata University Dental Hospital. This report is the investigation of the dental situation of these patients. The result were as follows:
1. The ratio of patients with blood diseases in our clinic was 0.7%. The patients with leukemia were most frequent.
2. Most of the first visit-patients with blood diseases were children aged 6, while the general patients group was younger. The ages of first visit-patients corresponded to the most frequent ages of primary diseases.
3. The majority of their chief complaints were “the treatment of decayed teeth for caries”. Others were “the extraction of loose teeth for exchange” or “the diseases of oral soft tissues”.
4. The patients visited our clinic from all over Niigata prefecture, some of which visited from a great distance and were introduced by Niigata University Medical Hospital.
5. As to the treatment of decayed teeth for caries, the patients with hemophilia had a large number of treated teeth as compared with the other diseases. In case of leukemia, anaphylactoid purpura and idiopathic thrombocytopenic purpura (ITP), the outpatients generally tend to be subject to more severe caries than the inpatients in Niigata University Medical Hospital.
6. The percentage of recall of patients with blood disease was lower than that of general children at the rate of about 20%. Almost 75% of patients who did not visit our clinic for recall were inpatients at first visit.

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A clinico-statistical survey was carried out on dental treatment for children under general anesthesia who visited the clinic of Pedodontic Department, Matsumoto Dental College Hospital during the period of 1986 to 1989.
The number of cases subjected in this survey was 108 (57 boys 51 girls), aged from one year and 5 months to 8 years and 9 months. All of these patients were admitted to the hospital for 3 days and were treated under general anesthesia, using GOE in 107 cases (in 80 cases by nasal intubation in 27 cases by oral intubation).
One case was administrated by intravenous anesthesia with Ketamin.
The results were as follows.
1. The patient ages of the patients ranged from one year 5 months to 8 years 9months.
2. Thirteen percent of the patients were handicapped. Fifty three percent of the pateints had to visit hospitals in remote areas.
3. The number of restored teeth per patient was 15 on the average. The teeth were treated with composite resin filling in 8.5 teeth, composite resin crown in 2.6 teeth, metal crown 3.6 teeth and other material in 0.8 (extraction).
4. Pulpal treatment was carried out on 42 percent of the subjected teeth.
5. The average anesthesia administration time was 3 hours and 28 minuts. No serious trouble was observed although minor complications were seen postoperatively such as high fever or vomiting in some cases.

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It is a relatively common clinical experience to see an impacted permanent tooth. In most cases, the cause is considered to be the existence of a supernewmerarytooth or developmental crowding, but occasionally, the impacted tooth may occur with no apparent cause. The tooth most frequently impacted in the dental arch is a maxillary permanent canine or the third permanent molar, but the occurence of the first permanent molar is an extremely rare situation.
The patient, an eight-year, seven-month-old male was referred to the Pediatric Dentistry Clinic at the Higashi-Nippon-Gakuen University, School of Dentistry, for a detailed dental examination of his impacted lower permanent first molars. The oral findings through dental examination revealed that the bilateral upper first permanent molars were erupted, while the lower ones showed no clinical signs of eruption. Radiographic examination revealed that the lower second permanent premolars placed under the distal root of the second deciduous molars, and the first molars, inclined to the mesial position, placed at the under the second premolars bilaterally.
There was nothing particular in his medical and dental history during the “teething” period. The authors determined that the cause of this impacted condition for the first molars seemed to be induced by a migration of an unerupted second permanent premolars.
After extraction of the second deciduous molars and second permanent premolars, orthodontic therapy was undertaken in an attempt to move the impacted first molars into the arch. It is imperative that a panoramic survey is made to discover such malposition because early detection of the developing malposition and removal of the causative factor may prevent the displacement and transmigration on unerupted tooth.

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