There exists a considerable literature on tumors of the oral region, but little work has been done to study oral tumors in children. A comparison of the rates of incidence with respect to location, sex and age of Japanese children, including a comparison of published materials concerning adults and children in other countries is very important. In the present paper,69 cases of oral tumors in children (under 16 years of age), who were referred to the Dental Hospital of Iwate Medical University for the past 12 years, were examined and classified clinico- and histopathologically. The results were as follows:
1) Tumors composed 29.7 per cent of all biopsied and operated specimens in children.
2) The incidence of tumors occurring in the soft tissue decreased with age, and conversely, the incidence of tumors occurring in the jaw bone increased.
3) Almost of all of the tumors were benign, malignant tumor being found in only 5.8 per cent of the cases.
4) The most common regions of soft tissue where tumors occurred were the cheek, tongue, gingiva and lip, with angiomas being the most frequent histopath ologically.
5) 82.9 per cent of the jaw-tumors was of the odontogenic type, and two thirds of these odontogenic tumors occurred in the mandible. The most common histopathological types of tumor were odontoma, ameloblastoma and odontogenic fibroma. Non-odontogenic tumors in the jaw bone included osteoma, benign osteoblastoma, fibroma and giant cell tumor.
6) Malignant tumors consisted of four cases, three of which were non-epithelial origin.
Based on the above-mentioned data, wefound that the incidence of odontogenic tumors in children was higher than other reports. As this was due to geopathological factors as well as other factors, further studies in this area are therefore necessary.

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Dental care for the peoples Living in the islands where there are no dentists encounters many difficult problems. One of the major problems is a deficiency with respect to the dental needs. Temporarily organized therapeutic teams have principally supplied emergency treatment, but such emergency measures have not effectively improved the oral health status of epople in the detached islands, because therapeutic measures can not reduce amount of the need for dental treatment, and therefore can not bring about an introduction of the guidance Requined for dental health care.
The present study aimed to explore an actual and effective program for the improvement of oral health of children living in islands having no dentists.
The data were obtained from the residents of a village in Kagoshima Prefecture, Mishima-mura consisting of 3 small islands. Preschool and school children and their parents and other adult residents were examined with respect to their oral health status and dental home cares.
Cultural backgrounds of the villigers were also investigated.
The results obtained were as follows:
1) Rates of untreated carious teeth were very high among the children of Mishimamura. The prevalence of caries differed among the children of the 3 islands.
2) Oral hygiene habits of the children were generally good, but habitual intake of caries-inducing foods as between-meal snacks was a major problem. Also dental home care practices differed among the 3 islands.
3) Home and social environments that seem to be closely related to the prevention of caries were unsatisfactory from a view point of the practice of good oral health cares for children. These elements also slightly among the 3 islands.
4) Cultural backgrounds, particulary transportation and communication, greatly influenced the propagation of knowledge and practice of dental health care and the prevalence of dental caries.

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It is suggested that repeated health care guidance is required in order to improve the oral health of children. To bring this about at present, the most practical way would be the incorporation of a more intensive oral health guidance program into the Medical Examination and Guidance for the Infants Aged 4 Months.
The present study aimed at exploring the most effective program for the improvement of oral health among young children. Infants aged 4 months and their mothers, who visited the Nishi Health Center in Suginami Ward in Tokyo for the medical health program, were chosen, instructed in daily home care for the prevention of dental caries, and examined for the changes in their oral health status and behaviour after 12 months.
The results obtained were as follows:
1) Instructions given only once when the child was 4 months of age were without satisfactory effect, but 3 successive sessions instruction given the subsequent 12months provided a improvement in the daily home care and oral health of children, particularly in the dietary habits.
2) Dental health behaviour of the group with detectable dental caries generally showed bad daily home care. More frequent and irregular ingestion of sugarcontainning snacks was observed in the caries-prone group than in the caries-free group.
3) The instructions even if repeated from when the child was 4 months of age did not stop habitual finger-sucking.
These results suggest that dental health care guidance first given to the child at 4 months of age should be reinforced by 2 or more successive sessions of instruction at 3-4 months intervals and that a control of the ingestion of snacks with a high content of sugar is most important for improving the oral health of children.

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For the purpose of studying secular changes of tooth and jaw reduction as well as the occurrence and progress of tooth to denture base discrepancy, the authors have already investigated dental diseases of Japanese skeletal remains from several periods. However, no dental caries of deciduous teeth has been found so far, possibly because very few samples of deciduous or mixed dentition have been obtained.
Recently, the authors had an opportunity to examine 183 skeletal remains ranging from the early stages of the Jomon to the Kofun periods stored at the Department of Anatomy, Faculty of Medicine, Nagasaki University. Among these materials, there were 21 crania with deciduous or mixed dentition, three from the later Jomon period,17 from the Yayoi period and one from the Kofun period. The present paper deals with the results of dental examination based mainly on samples from the Yayoi period, for it seems quite uncommon to meet such a large number of samples of this kind.
There were eight cases of normal occlusion, three of anterior cross-bite and two cases of crowding out of 13 cases with good conditions for orthodontic diagnosis of their occlusions. With respect to the pathogenic factors of malocclusion, there were three cases involving the skeletal factor(23.1%), one case involving the functional factor (7.7%) and two cases involving the discrepancy factor (15.4%). There was no evidence of dental caries of deciduous teeth in the Jomon nor Kofun periods. However, several cavities were found on deciduous teeth in the Yayoi period, namely two carious teeth in 15 maxillary deciduous central incisors, two in 27 maxillary first deciduous molars, and four in 53 maxillary and mandibular second deciduous molars, which included four C₁ and four C₂.
Suspicious traits of marginal resorption of the alveolar bone were observed at the deciduous molar region in only one case, but it was not confirmed whether periodontal disease was already in existence among the Yayoi children.
Based on roentgenographic cephalometrics, it was evident that the madnible of this period showed a well developed pattern even in early stage of mixed dentition corresponding to the findings in adult samples, which seemed to explain the higher rate of anterior cross-bite with the skeletal factor. The size of the total discrepancy according to Tweed (1944,1945) could be estimated in only two cases giving a mean value of plus 2.4 mm.
It was conclussively shown that 1. the Yayoi people had a quite defferent facial pattern from the former habitants of Japan,2. it was a time in which the environmental pollution in the mouth was the severest among the various historic periods, and 3. the discrepancy between teeth and jaw bones, and consequently its influence on dental diseases were not so dominant in that period.

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The developmental process and the stability of the occlusal relationship of the permanent first molar were observed longitudinally from the primary dentition to the permanent dentition. The materials were considered of a total of 1318 pairs of serial plaster models which had been taken every three months, ranging from Hellman's Dental Age IIA to IIIC period. Observation was made in 72 cases which were divided into the right and left side of the dentition of 39 Japanese children.
The results are summarized as follows:
1. Of 41 cases which had remained in the mesial step from IIA to the period of the exfoliation of the second primary molar,22 cases finished as a Class I relationship, and 19 cases finished as a Class III relationship in IIIC period.
2. Of 4 cases with the mesial step in IIA period,
3 cases which had changed to the vertical plane in IIC period, and one case which had changed to the distal step in IIC period finished as a Class II relationship in IIIC period.3. The cases with the mesial step in IIA period which would finish as a Class I or Class III relationship in IIIC period kept a Class I relationship before the eruption of permanent second molar. It was, however, after the eruption of the second molar that some of the cases changed the relationship into Class III in IIIC period.
4. Of 16 cases with the vertical plane in IIA period,11 cases which had changed to the mesial step in IIC or early IIIB period finished as a Class I relationship in IIIC period, and 5 cases which had changed to the distal step in IIC period finished as a Class II relationship in IIIC period.
5. The cases which had remained in vertical plane and finished as a Class I relationship in IIIC period had the normal occlusal relationship of the first permanent premolar. The cases which had remained in the vertical plane but finished as a Class II in IIIC period had an unstable occlusal relation ship that the maxillary first premolar occluded distally to the mandibular first premolar.
6. All of 6 cases with the distal step did not change the terminal plane, and finished as a Class II relationship in IIIC period.

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The authors investigated histopathologically the effects on deciduous pulp of a glass ionomer cement called “Fuji Ionomer Type-II”, using 52 nonexposed teeth and 2 exposed teeth of 11 young dogs, over periods of 1 and 3 days or 1,2 and 4 weeks after the operation.
The results obtained from this study were as follows.
1) Pathologically,29 cases (56%) were evaluated as “Good”,18 cases (35 %)“Fair”,5 cases (10%) “Poor”.
2) The inflamation of the dental pulp was observed even after 4 weeks.
3) Cases with poor results had only a thin layer of the remaining dentin. (less than 180 & thickness of the remaining dentine).
4) Secondary dentine formation was observed for 2 and 4 weeks after treatment but this involved only a few (15%) of all cases.
5) Pathologically,2 cases of exposed pulp were evaluated as “Poor”. In cases of exposed pulp the reaction was severe and necrosis was observed. We concluded that the glass ionomer cement caused a little more irritation than did the carboxylate cement with respect to the dental pulp.

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A 1 year and 11 month-old child with cerebral palsy, who had been suffering from mobility of lower anterior teeth, visited the clinic for Pediatric Dentistry at Hokkaido University Dental Hospital.
The patient had not shown any carious resions but all anterior teeth were mobile. He was found to have obvious stigmata of severe bruxism.
A absorbed bony features of the alveolar crestal bone were found in all resions by means of examination.
Laboratory findings revealed evidence of leukocytosis, and elevated levels of GOT, GPT, IgA, IgM and IgG as well.
Although these findings were not confirmed with respect to their relationship to this disease is concerned, they are nevertheless interesting.
Histological study of the teeth demonstrated that the roots of the teeth were shorter than those of the control.
These findings, not only revealed the regressive pathological changes of the alveolar regions, but also showed the early exfoliation of primaly teeth.

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Treacher Collins Syndrome, which refers to the developmental anomalies of the first and second branchial arches as a pathogenesis, is very rare disease. This syndrome prominently exhibits congenital facial anomalies. Although its etiology is not known, the hereditary factors have clearly been demonstrated in the literature. This syndrome is most likely transmitted in the autosomal dominant mode of inheritance.
This is a report of a 7 year-old girl with the Treacher Collins Syndrome, whose older sister, mother and maternal grandfather have also revealed this syndrome.
The patient was found to exhibit all of the clinical stigmata in the syndrome and she appeared to be a complete type of this disease according to the Franceschetti and Klein classification. There were indications that her older sister and mother were clinically found to have almost all of the clinical features of this syndrome as well and they were also classified as a complete type. The maternal grandfather seemed to reveal an incomplete type of this disease.
The family which we investigated clearly demonstrated the autosomal dominant transmission of this disease based on the study of their pedigree. We have traced and examined the four affected members of this family through three generations and their phenotype seemed to be worsening progressively generation after generation.
The clinical and dental findings of this family and a veriew of literature is reported.

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Supernumerary teeth are frequently investigated and many reports have been reported on by different investigators. The majority of these teeth are located in the region of the maxillary incisors and are generally conical or unusual in shape. The number of supernumerary teeth is usually one, the incidence of multiple supernumerary teeth being very low.
Here we shall report on a case of four supernumerary teeth in the maxillary permanent incisor area of a 9-year-old boy. At the first visit, clinical examination revealed the following dental pattern: _??_ (S is supernumerary tooth). X-ray examination disclosed three impacted supernumerary teeth in the maxillary incisor area. One of them had erupted on the palatal side away from the normal aligment. The other three were impacted and inverted in position. One of them was of the so-called "Mesiodens" shape. Their shapes were as follows: two of them were of the three-cone shape; one, of the four-cone shape; and one, of the five-cone shape. The supernumeraries caused delayed eruption of the central permanent incisors. Both lateral permanent incisors had erupted. Immediate extraction of the supernumeraried was indicated. About 50 days after the operation, both incisors had erupted, but their orientation resulted in malocclusion. This patient was placed on follow-up.

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Multiple occurrences of the submerged primary molars are relatively rare compared to the cases of one or two teeth.
This is a case report of the submergence occurred in all eight primary molars of a 7 year-4 month-old Japanese girl.
The patient was referred to the Pedodontic Clinic of Tsurumi University Dental Hospital for the treatment of the masticatory dysfunction due to the total submergence of the primary molars.
Clinical examination revealed masticatory dysfunction and lateral tongue thrusting as a result of the posterior open bite caused by the total submergence, and the functional anterior cross bite resulted from incisal mastication.
The submergence of these primary molars increased in severity as the eruption of the permanent first molars and the permanent incisors proceeded. The masticatory dysfunction was treated by constructing overlay dentures after stainless steel crown restorations were rendered on these eight primary molars.
The follow-up cephalometric tracing showed that these primary molars stayed in the same position, while the upper and lower first permanent molars grew vertically, indicating clearly that the submergence is mainly caused by the vertical growth of the adjacent teeth and their supporting tissues.

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Amelogenesis imperfecta is known as a hereditary disease, which affects the phenotypic stigmata of the enamel of all or nearly all of the teeth. Two cases diagnosed as amelogenesis imperfecta were referred to the Pedodontic Clinic of Tsurumi University Dental Hospital for treatment of dental caries.
We studied their clinical findings as far as enamel dysplasia is concerned and also examined radiographic and histological findings concerning these affected teeth. These findings seem to indicate that cases 1 and 2 were favorable for the hypomaturation and hypoplastic types respectively. These cases also demonstrated the inheritance modes of the autosomal dominant type in case 1 and of a possible autosomal recessive type in case 2, according to their pedigree studies.
Because of considerable variation in the degree of enamel hypoplasia, it was indicated that the importance of treatment depends considerably upon the growth of the occlusal condition, and the development of physical and psychological status of the patient.

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A very rare case, a median incisor fusion, was seen both in primary and permanent dentitions of a 5-year-old Japanese girl, who visited the Pedodontic Clinic of Tsurumi University Dental Hospital. These median incisors appeared in the primary as well as in the permanent dentition and were extracted for esthetic reasons and subjected to morphological and histological examinations.
The etiology of the median incisor fusion is also discussed. The following findings were obtained:
1) Morphologically, both median incisors showed no traces of fusion and their appearance was more like that of a single normal tooth, except that they were mesiodistally symmetrical and the mesiodistal width of the primary median incisor was larger than that of the Japanese average of upper primary central incisor.
2) Histologically, there was no evidence of fusion between upper right and left incisors. Their structure was more like that of a single normal tooth.
3) Embryologically, it is reasonable to consider that it originated from a single germ rather than from two germs fused completely. The possibility of a relationship between the median incisor fusion and her nasal disease was also pointed out.

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The previous reports of both epidemiological and animal model studies demonstrated that the element molybdenum (Mo) might have some anti-caries effects. We have recently developed a new chemical agent, (NH₄)₂MoO₂F₄, containing both fluoride and molybdenum as anti-caries elements. Animal model studies revealed that the topical application of 10% (NH₄)₂MoO₂F₄ significantly reduced the dental caries in rats.
In this paper, we described the effects of (NH₄)₂MoO₂F₄ on human enamel in vitro. After topical application, the solubility of the enamel by an acid buffer was evaluated by measuring the calcium loss. In addition, the reduction of artificial caries-like lesions was investigated by means of polarizing microscopic analysis, microradiographic examination and electron microprobe analysis. To confirm the effects of this agent, NH₄F and (NH₄)₆Mo₇O₂₄.4H₂O were employed with equal concentration of fluoride or molybdenum at same pH.
Compared with two agents containing fluoride or molybdenum, (NH₄)₂MoO₂F₄was found to be most effective for protecting the enamel surface. However, (NH₄)₆Mo₇O₂₄.₄H₂O also showed a considerable effect.
These results suggest that molybdenum has an anti-caries property and increase the effect of fluoride.

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The purpose of this study was to investigate the actual feeding conditions of handicapped children. All food intake over a period of three weekdays for eighty children, who were referred to our clinic for recall, were studied. Their average age was 9 years and 1 month, ranging from 5 to 12 years. Of the nutrient intake per day, calorie, protein, carbohydrate, Ca, Fe, V. A, V.B₁, V.B₂, niacin and V. C were calculated according to the age and weight. Of the subjects we have also investigated nutrient intake and the oral condition based on each item of the questionnaire filled out by mothers of handicapped children.
The findings were as follows.
1) As a whole, the nutrient intake was not poor and unbalanced.
2) Analyzing the average nutrient intake according to their disorder, there was no significant difference on the basis of age and weight.
3) The nutrient intake of protein, Ca and V. B₂ was slightly higher in the groups whose feeding method was always included outside help, whose motor function of the hand were disabled and the types of food was soft.
4) Analyzing the average nutrient intake from the view point of appetite and the likes and dislikes of the various foods, there was no significant difference both in volume and balance.
5) So called severely handicapped children had a lower decayed and filled tooth rate, newly decayed tooth rate, and revealed a better outcome in the caries activity test.
6) In the group with bad oral conditions, the carbohydrate ratio was slightly high.
7) Sucrose intake per day was about 20 gr. on the average, and there was no difference based on the types of disorder.

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