The mesio-distal crown diameter of the deciduous teeth and size of the deciduous dentition were measured, in 64 children born between 1970-1975, and the terminalplane and interdental space of the deciduous dentitions were observed, for the purpose of evaluating the state of the deciduous dentition among Japanese children today. After measuring mesio-distal crown diameters, sexual demorphisms were recognized in maxillary canine, maxillary first deciduous molar and mandibular second deciduous molar, and the males were larger than the females. After measuring the size of deciduous dentitions, sexual demorphism was recognized, and the males were larger than the females, it is as with the crown diameter. The width of the maxillary dentition of the males growth larger with age, but in other part no growth was recognized. Observing the terminal plane, the vertical type amounted to 34.9%, the mesial step type 22.2%, the distal step type 14.3%. Observing interdental space, spaced type accounted for 90.7% in the maxilla, and 87.5% in the mandible.
These results were compared with the da ta reported by Ono (1960) about 20 years ago. A difference in the mesio-distal crown diameter of deciduous teeth was not found, but the size of deciduous dentition becomes to smaller especially in the anterior of the maxillary dentition, and moreover the vertical type decreased and the distal step type increased. Based on these results, it was considered that the stunted growth of the deciduous dentitions was caused not only crowding of permanent dentition, but also discrepancy of the maxilla and mandible like mandibular retracted occlusion.

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This study was carried out in order to survey the status of the Prevalence of dental caries among the deciduous teeth of day-nursery-children (254 boys and 252 girls ranging from 1 to 6 years of age) and kindergarten-children (207 boys and 201 girls ranging from 4 to 6 years of age) in Kohriyama city, Fukushima prefecture where Tohoku Dental University is located. The df was used as the dental caries experience index, and the caries attack patterns were investigated according to the classification of The Ministry of Public Welfare used for dental inspection of 3-year-old Japanese children.
The results were as follows:
1. Day-nursery- and kindergarten-children revealed a higher prevalence of dental caries with advancing age.
2. In all age groups from 4 to 6 years the kindergarten-children showed a higher caries prevalence than the day-nursery-children.
3. Day-nursery- and kindergarten-children grew better in the status of the dental caries treatment with advancing age. The kindergarten-children showed better status of the caries treatment.
4. Maxillary central incisors in the deciduous dentition showed the highest caries prevalence rate in 2-year-old children, and mandibular first or second molars showed the highest caries prevalence rate in children over 3 years of age. Mandibular incisors showed the lowest, and a somewhat higer in children oves 4 years of age.
5. Frequencies of the caries-attack-pattern-A₁ group which had caries lesions only in maxillary and/or mandibular molars showed little change in all age groups, and frequencies of the pattern-A₂ group which had caries lesions only in the maxillary anteriors showed a decrease with advancing age. The frequencies of the pattern-B group which were combinations with A₁ and A₂, and the ones of C group which involved also mandibular anteriors showed a tendency to increase with advancing age.

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Male rats of the Wistar strain, three weeks old, were placed on a diet mixed with sardine powder containing a large quantity of calcium, and the effect of calcium on alveolar bones and femurs in the growing stage was investigated for body weight and photographic density, and radiologically and photographically.
The results were as follows:
1. The body weight of those in the experimental group increased with time as it did in the control group. However, the values were slightly lower than those of the control group.
2. Radiologically and photographically, the photographic density of the alveolar bones and femurs of those in the control group was higher than that of those in the experimental group up to the seventh week. From the eight week, however, the experimental group showed a higher density.
3. Concerning photographic density, the bone density of the alveolar bones and femurs of the control group increased faster than that of the experimental group. From the eighth week, however, the density decreased compared with the experimental group. The bone density for the experimental group showed a stable increase with time. In addition, the experimental group showed a higher density than the control group from the eighth week.
On the basis of the foregoing findings, it was proven that intake of sardine powder had an effect of increasing bone formation in alveolar bones and femurs in growing stage.

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For the purpose of investigating the thickness of the dental structure in the maxillary first deciduous molars, the distance between the pulp cavities and the external boundaries of the teeth were measured. The materials used were 71teeth, some without caries and some with caries localized to the enamel. The degree of the attrition was limited in the line on the summit of the cusps. The classification of the specimens and the methods of the investigation applied were similar to those applied to the maxillary second molars reported previously. To put it briefly, these specimens were divided into 3 types according to the root resorption. The specimens embedded in epoxy resin were sliced mesiodistally into serial sections of 93μm. The serial sections were enlarged ten times by tracing, and were three-dimentionally reconstructed using a personal computer. The distances from the various points of the pulp cavity to the surface of the crown, were measured on the reconstructed stereogram. The observational regions used for these measurements consisted of the occlusal aspect, mesial aspect and the cross-sections of the center of the bucco-lingual diameter, the center of the central groove and the bucco-lingual horns of pulp chamber. Results:
1) The smallest measurement for the distance from the pulp cavity to the occlusal surface was 2.5 mm at the buccal horn of pulp chamber.
2) The smallest measurement for the distance from the bucco-lingual horns of the pulp chamber to the bucco-lingual and interproximal surfaces was about 2.3 mm at the distance from the buccal horn of the pulp chamber to the buccal surface.
3) The smallest measurement of the distance from the maximum bulge of the pulp cavity to the bucco-lingual and the interproximal surface was 1.4-1.5mm. This phenomenon was observed at the mesial side in the bucco-lingual aspect and the center of the central groove.
4) The smallest measurement in the cervical regions was 1.1-1.2 mm at the mesial side of the buccal aspect.
5) The bucco-lingual horns of the pulp chamber existed just under the summit of each cusp mesio-distally. The bucco-lingual horns of the pulp chamber were inside of the summit of their cusps bucco-lingually. The distance was 0.7 mm at the buccal side and 1.0 mm at the lingual side.
6) According to the degree of the resorption, there is almost no difference in the thickness of the dental structure between type I and II.
Therefore, regardless of the degree of the root resorption, the attention appropriate to every portion must be given to the occasion of cavity preparation.

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The effects of Streptococcums utans immunization on experimental dental caries and antibody responses were investigated in rats. Fischer rats (F344) were immunized with formalin-killed S. mutans 6715 (serotype g) by means of subcutaneous or intravenous injection, and gastric intubation. The rats were infected with live S. mutans 6715 and fed a caries inducing diet containing 20% sucrose. Dental caries and serum or salivary anti-S. mutans antibody responses were compared with an unimmunized group of rats.
The following results were obtained.
1. Immunization with S. mutans inhibited experimental caries in rats. This inhibition was greatest in the group of rats immunized by subcutane ous injection in the vicinity of the submandibular salivary glands, followed by intravenous injection and gastric intubation (oral immunization).
2. Serum and salivary anti-S. mutans IgG antibody levels were elevated in the group of rats immunized by subcutaneous and intravenous injection. E nhancement of IgA anti-S. mutans antibody responses was observed in the rats immunized with S. mutans by not only parenteral but also oral routes.

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The purpose of this study was to evaluate the electromyographic activity and the duration of occlusal sounds during tooth tapping in children and to compare these with those of adults, and further to attempt the possibility of any clinical application of the EMGs and the duration of occlusal sounds to the functional diagnosis of occlusion in children.
43 subjects were examined and placed into three groups; a group with deciduous ciduous dentition (15 children), a group with mixed dentition (13 children) and a group with permanent dentition (15 adults). EMGs were recorded from the anterior temporal and masseter muscles bilaterally using bipolar silver surfacedisk electrodes. Occlusal sounds were obtained with an accelero-type cardiac transducer placed on the center of the forehead.5 children with deciduous dentition were selected from 15 children to evaluate the influences of the occlusal interferences on the masticatory muscles of children induced by the experimental metal overlay placed on the mandibular right deciduous second molar.4 children with carious primary molars were used to examine the changes of EMG activity and the duration of occlusal sound after restorations with the preformed primary crowns.
The results obtained in the present study were as follows:
1. DPTC (duration preceding tooth contact) obtained in the group with deciduous dentition showed the longest among the three groups. DOTC (d uration outlasting tooth contact) in the mixed dentition group showed the significantly longest.
2. APTC (activity preceding tooth contact) of the anterior temporal muscle was significantly larger in the deciduous dentition group than in the permanent dentition group. AOTC (activity outlasting tooth contact) showed the largest value in the mixed dentition group.
3. In regard to the duration of occlusal sounds, it was the shortest in the deciduous dentition group followed by the permanent and mixed dentition groups.
4. Immediately after the experimental occlusal interferences, DPTC showed a prolonged tendency on temporal and masseter muscles of interference side and DOTC showed a longer tendency for all muscles. The duration of occlusal sound showed a shorter tendency at 3 days after placement of an overlay.
5. After placement of chrome steel crowns, total burst durations were revealing the same values shown in normal group of deciduous dentition. However the durations of occlusal sounds were prolonged in 3 subjects.
The results suggest that preferential masticatory muscle activities related to the tooth tapping were different between children and adults. During tooth tapping, temporal muscles are dominantly working in children. Duration of the occlusal sounds is presumably affected by the stage of dentition. Also the resuits of clinical study suggest that it is possible to apply the EMGs of masticatory muscles and the duration of occlusal sounds during tooth tapping clinically to the functional diagnosis of occlusion in children.

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The purpose of this study was to understand the relationships among various aspects of oral disorders in handicapped children, especially children with cerebral palsy. We examined the oral conditions of 243 children with cerebral palsy in three institutions for the physically and for the severely and multi handicapped. As the second part of the study, we surveyed the tooth development, the eruption of deciduous and permanent teeth, dental arches and occlusion of CP children, based on oral examination and X-ray examination. Further we investigated the relationship between these oral conditions and the degree of oral functional disorderes.
The results were as follows.
1) As to the eruption of the teeth, the retardation of the eruption of the second primary teeth was observed, and the eruption of first molars and premolars were observed to be retarded compaired with the eruption of the anterior teeth.
2) Regarding the relationship between the eruption of teeth and the degree of oral functional disorders, those who had a fewer number of teeth erupted in the primary dentition than the average number of primary teeth in normal children, were all found to have oral functional disorders to some extent. In the mixed or permanent dentition, it can be seen that CP children with a greater severity of the oral functional disorders had a fewer number of permanent teeth erupted.
3) Observation with X-rays showed that the incidence of the malposition of teeth, as impacted teeth and dislocationed teeth, increased as they grew older after the period of mixed dentition.
4) As to the dentition and occlusion of CP children,30% of the children with deciduous dentition were recognized to have malocclusion, mainly openbite. From 20 to 50% of the children after the mixed dentition had openbbite, prognathism and constriction of the dentition.
Regarding the relationship between the malocclusion and the degree of oral functional disorders, a high incidence of malocclusion was observed in the childr en with a severe degree of oral functional disorder during the period of primary dentition, but the incidence of malocclusion was high in the period of mixed and permanent dentition and was not related to the severity of their oral functional disorders.

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The caries-inducing activity and the caries-inhibitory activity of Glucosyl-(GOS: a panose and maltose rich sugar mixture) were examined in in vivo experiments. Specific-pathogen-free rats were infected with Streptococcus mutans 6715 and fed cariogenic diet 2000 or a modified diet containing different sugars in place of 56% sucrose in diet 2000. The caries-inducing activity of GOS was one fifth of that of sucrose. The replacement of half of the diet sucrose content with GOS resulted in significant reduction of caries development. These results indicate that GOS is useful as an anti-cariogenic sucrose substitute.

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The purpose of this study was to evaluate the accuracy of the tooth tapping rhythm lead by a metoronome and to compare it to that in adults. Forty subjects were examined and classified into 4 groups; one group with deciduous dentition, one in the early period of the mixed dentition, one in the later period of the mixed dentition, and one with the permanent dentition. Occlusal sounds to the tune of 76 times per minute of tapping were obtained with an accelerotype cardiac transducer placed on the center of the forehead.
The results obtained in the present study were; Accuracy was improved and is closely associated with increasing age when more advanced movement capability is achieved.

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We conducted a survey on oral examinations during the first visit and recall visits of handicapped children.382 handicapped children (257 males,125 female) were examined. We used the 1st,2nd and 3rd classification as developed by Uehara.
Most of the patients were 5 to 9 years old. The average age was 7.4. The average number of untreated decayed teeth showed the highest peak from 3 ages to 7, but it decreased with age. Upon examining the dental treatments applied, it was found that restoration of the crown was the most common accounting for 37.4%. Prophylaxis, extraction of teeth and pulp treatment followed. Compared with normal children, the average number of treated decayed teeth was low. During recall visits after dental treatment under general anesthesia, they found more new caries. The decayed teeth required dental treatment again more often than in the case of the outpatient clinic.
In the case of dental treatment done in the special department for handicapped children, good results were obtained.

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Hallermann-Streiff syndrome is a congenital anomaly, characterized by bicongenital cataracts and the symptom known as “bird face”. Dental abnormalies were observed. These most commonly consisted of the bird face, neonatal teeth, hypoplastic teeth, partial anodontia and persistent deciduous teeth. We are reporting in this paper on a 7 year,10 months old boy with the Hallermann-Streiff syndrome.
The following are the dental findings.
1) According to X-ray cephalometric analysis, a retardation of the forward and downward growth of the maxilla and mandibula was found.
2) Also were edge to edge occulusion, an ogival palate, and a V-shaped arch.
3) All the teeth were microteeth, and persistent deciduous teeth.
4) According to an orthopantomo X-ray, we found an impacted supernumerary tooth in the maxilla, and partial anodontia.
5) The measurement of the length and width of the dental arch was small compared with the national average.

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We have many cases involving the management of impacted and displaced teeth after marsupialization of a dentigerous cyst. We would like to summarize the results of the report as follows:
1) We refer to three cases of especially impacted and displaced teeth in the large dentigerous cyst, in guiding their teeth into a normal arch position.
2) Suturing gingiva tissue to the cyst wall is effective in marsupialization to prevent closing.
3) They have a tendency to erupt as soon as marsupialization.
4) The teeth which had been displaced near the bottom of mandible and dislocated distally or messially by the pressure of the cyst on which had been displaced and inclined abnormally by the pressure of the cyst, have a tendency to erupt rapidly into their normal position soon after marsupialization, even without the application of orthodontic measures.
5) We feel that the space maintenance should be used with marsupialization before the treatment to secure the space to prevent the mesial inclination of the permanent first molar or to regain the permanent second premolar or the first permanent molar. We feel, this procedure, termed “ fenestration”, should not require a braket or wire placed on the unerupted exposed teeth to facilitate orthodontic movement into the occlusion.

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Topical application of 10% (NH₄)₂MoO₂F₄ solution has been shown to have a cariostatic effect in experiments using rats. A clinical study was planned to evalute the efficacy of topical (NH₄)₂MoO₂F₄ application on human dental caries. Ten children with dental caries on both sides of their dental archs were the subjects of this study. A 10% (NH₄)₂MoO₂F₄ solution was applied to the caries lesion on the experimental side, and distilled water was used as a control solution. Cariostatic effects or side effects of (NH₄)₂MoO₂F₄ topical application were examined periodically up to 15 weeks. Changes in the caries lesions were examined and scored on standardized photographs.
The following results were obtained,
1) Clinical examination showed that topical application of 10% (NH₄)₂MoO₂F₄solution inhibited the increments of both enamel and dentin caries without tooth discoloration.
2) It was found from standardized photographic analysis that topical (NH₄)₂MoO₂F₄ treatment significantly suppressed the increase in the area of caries lesions when compared with disstilled water.
3) There were no apparent side effects of (NH₄)₂MoO₂F₄ treatment except a slight gingival discomfort in 2 instances out of 92 applications.

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A 9-year-9-month-old girl was referred to the Pedodontic Clinic of Tsurumi University Dental Hospital, with a chief complaint of rampant caries of the permanent dentition. Consultation with her father revealed that she had been physically abused by her stepmother, and many bruises were observed on her face and limbs. She looked fearful and over-vigilant. It seemed apparent that the abuse given by her stepmother caused her poor oral condition and masticatory disorder. Because of this, careful handling of the patient as well as her parents was given particular consideration. Upper full and lower partial dentures were constructed by using X-ray cephalometric analysis for determination of the vertical dimension of the occlusion. Regaining of the masticatory function made her behavior gradually brighter, and the physical abuse by stepmother was reported to have been reduced to great extent. Child abuse is one of the contemporary social problems surrounding children, especially in the highly industrialized societies. We should be aware of its detection and control in both the dental and legal aspects.

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A case of a completely impacted lower left second primary molor in a 3-year-old boy is the subject of this report. An X-ray examination revealed that the lower left second primary molar was impacted. In addition, a radiolucent figure with a clear boundary was seen around this tooth. The lower left second bicuspid is not observed on the radiograph. There was nothing particular in his past medical and dental history to indicate the cause of this anomaly. After surgical exposure, orthodontic forces were applied to bring the tooth into the oral cavity with an intermaxillary powerchain between the hook attached to the tooth with D. B. S. and the lingual arch in the maxillar. The tooth was fully erupted to the occlusal plane approximately 19-months postoperatively.

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