When mandibular incisors have erupted fully, there are two conditions of their alinement. The one is the group whose teeth aline regularly (Normal group), the other one is the group whose teeth crowd (Crowding group). The purpose of this study is to find what causes the difference between the two.
Materials consisted of study series of casts taken from 29 children, whose oral conditions in the deciduous stage were acceptable, and moreover, in whose growing process, situations such as premature loss, improper habit, and so on, which directly dominate tooth alinement or development of occlusion, were not found. On the average, children were observed ranged from 5 years of age to 8 years and 9 months of age, and the interval of this observation was 3 years and 6 months.
After the subjects was separated into 2 groups, diffe r ences between the two were investigated with respect to the tooth form, the arch form in the deciduous stage, and the changing process of dental arch. Moreover, how these differences take part in the alinement of mandibular permanent incisors was investigated by the factor analysis method.

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Pulpal reaction to GK-101 solution, which is selectively solvent to carious dentin, was histopathologically investigated using young dog teeth. Phisiological saline was used as a control. The results were as follows:
1) Experiment I: Application of the solution in the prepared cavities. No significant differences were observed between the GK-101 group and the physiologic al saline group, indicating no irritating effect on the pulp.
2) Experiment II: Application of solution after pulp exposure. It is difficult to determine the effect of the solution on the pulp, since Dycal used for pulp capping mark edly affected the pulp response.
3) Experiment III: Application of solution after pulp exposure in the root buccally through gingiva, alveolar bone, periodontal ligament, cement and dentin. The pulpal inflammatory reaction was mild and early reparative response was found, in comparison with the results of the Experiment II. Consequently, it was concluded that GK-101 solution was not irritating to the pulp.

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Abstract: For the purpose of investigating severe deciduous caries from seroimmunological standpoint, a total of 34 infants ranged in age from 3.4-6.9 years were examined. The subjects, having pulpinfected caries and diseases on root apex but free from any pediatric diseases (henceforth referred to as S group), were subjected to seroimmunological examinations, namely, serum protein and serum immunoglobulin tests, before and after the dental treatment. Infants having no dental caries and physically in good condition (henceforth referred to as C group) were also subjected to immunological examinations, and the results were compared with those of the S group. The following were the results of the investigation.

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Improved plaster models of upper and lower second deciduous molars were made from Japanese infants ranged in age from 2.5-3.5 years. A total of 152samples of upper second deciduous molars (M: 74&F: 78) and 146 counterparts in the mandible (M: 64&F 82) were examined in terms of types and frequencies appearance of accessory grooves and converging relationships of accessory grooves into grooves. The following were the results of the examination.1. Upper Second Deciduous Molar

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We have experienced a 13 year 2 month-old boy, diagnosed as Letterer-Siwe disease and a 11 year 6 month-old girl, diagnosed as Hand-Schiiller Christian disease, who has been followed for about 7 years.
Oral and facial findings of the two cases were as follows.
1) In the case diagnosed as Letterer-Siwe disease, the maxillary bone were showed absorption severly, meanwhile the mandibular bone were less absorption as con trasted with maxilla.
2) Loosening and exfoliation of teeth and gingivitis were found intensively in both cases.
3) In the case diagnosed as Hand-Schuller-Christian disease, absorption of the alveolar bone and itselves in mandibula and maxilla had been progressing for about 7 years. Meanwhile the bone absorption of skull and costae weren't found at 11 year 6 month -old.
4) In the two cases observed, comparing the oral manifestations with the other physical manifestations, it was recognized that the oral manifestations occurred prev ious to the pysical manifestations.

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This investigation was made in order to serve as an aid in the diagnosis and prognosis of mandibular protrusion in the deciduous dentition from the standpoint of the correlation between form and function. The subjects consisted of 14 preschool children whose lower jaws were protruded (SNA angle of these subjects were over 80.0 degrees). The controls, so called normal occlusion, consisted of the same number of preschool children. Electromyographs (EMG) were recorded bilateraly on the anterior temporal muscle (TA), the posterior temporal (TP) and the superficial portion of the masseter (M), during the gum and peanuts free chewing and max. biting. Maximum amplitudes were measured on 20 strokes in each chewing and on 5 strokes in max. biting. Thereupon, the _??_and_??_ratio and TA%, TP%, M% were calculated in each chewing and max. biting. These EMG data of the mandibular protrusion group were compared with that of the normal occlusion group. The correlation coefficiets among EMG data and cephalometric data in the mandibular protrusion group and the normal occrusion group, were calculated. The results obtained are summaried as follows

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Electromyograms of masticatory muscles on tonic neck reflex on dorsal flexion in 18 children were recorded in order to evaluate the correlation between the neuromuscular activities of the masticatory muscles, and the dental and cephalometric analysis.
The following findings were obtaine:
(1) In 9 children out of 18, the activities elicited were different between the right and left side muscles and these children were refered to as Group II, and the ot her children who showed no differences were refered to as Group I. Temporal mu scles showed more sensitivity than the other two muscles, e. g. m. masseter, m. diga s tricus.
(2) There was a high correlation between the asymmetric muscle activities and occlusal factor, such as over bite, over jet, canine relationship, the degree of attritio n and the ratio of upper to lower jaw length. The occlusion of Group II in wh ich muscular activities were shown to be asymmetric, presented a tendency towa rd a deeper dite, and an increased difference of the length between lower jaw against upper jaw.
(3) Cephalometric analysis disclosed a tendency for antero-posterior differences, such as angle of convexity, A-B plane angle, A-B difference, and for the length of mandible, such as Gn-Cd, Cd-Go. The length of the mandibular body of Group II i s shorter than that of Group I.
(4) Based on the above findings with respect to the optimal occlusion ratio, the following was recognized. The over bite was 0.87±0.76mm, the over jet was 1.73±0.48mm, and the degree of the labial surface of the mandibular canine which covered that of the maxilla is less than half. The occlusion of the bilateral canines was symmetrical. Occlusal wear was within the normal range. The above factors were co nsidered to correspond to the optimal occlusion.

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A 10 years and 5 months old boy, was referred to the Department of Pedodontics, Gifu College of dentistry, with a chief complaint of caries treatment. But through radiographic examination, the patiant was diagnosed as a cleidocranial disostosis.
Oral, radiographic, cephalometric, and electromyographic examinati o n were made and following findings were obtained through these examinations.
1) Oral findings: Prematur e loss of many deciduous molars and delayed eruption of permanent teeth were observed. The palate was high and narrow, and cross-bite was observed in the anterior segment of dentition.
2) Radiographicfindings: R adiographic examination of the chest revealed bilateral partial absence of clavicles, and spina bifida occlta of the cervical. Cranial suture was not well fused and cranial bone was generally thickened. Coronoid process and angle of mandibule was sh on to be less ossified. Supernumerary teeth were observed in both jaws.
3) Cephalometric analysis: Cephalometric analysis re vealed anterior cross-bite which may be caused by frontal rotation of mandibular bone and flattened gonial angle.
4) EMG findings: EMG examinatio n did not show any abnormal discharge of masticatory muscles most likely to seen in other systemic disease as myotonia dystrophica, myotonia conge nita. But due to the premature loss of many primary teeth and delayed eruption of p ermanent teeth, he lost his habitual occlusion with disharmony of the co-ordination pattern of masticatory muscles. After insertion of denture, the disharmony of the co-ordinatio n pattern was slightly inproved.

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A right maxillary central incisor was displaced traumatically in an 8-year-old boy, and 40 hours had passed before he came to the Pedodontic Clinic, Gifu College of Dentistry.
In August 1979, the patient bruised him self against at the wall of the swimmingpool, and exarticulated and invaginated. At the clinic, the tooth socket was gently curetted, the avulsed tooth was kept in penicillin solution and then tooth was packed with gauze soaked in saline while the periodontal membrane adhering to the root surface was scraped off, and then the root canal was filled extraorally with Calvital®, then the tooth was reimplanted and repositioned in the socket, and stabilised with a splint and with the lateral incisors.
Radiographic examination was made regularly. During the first 9 months the radiographs showed a very favorable prognosis without any apparent change surrounding the root of the reimplanted tooth, but peripheral resorption of root appered while the tooth was firmly fixed in the socket clinically.
Reimplantation is clinically accepta b le treatment, especially among young patients, whose teeth and alveolar ridge are still developing. Although the reimplanted tooth have to be removed eventually because of root resorption. It is worth maintaining the teeth for a few years to prevent the emotional shock caused by trauma, and also to provide the possible developing of the alveolar ridge, which is necessary for future bridge work.

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This study was designed to measure the angle between the occlusal plane and labial or buccal surface of deciduous teeth in the lateral segment. The data were obtained from 109 dental casts of 3-year-old children with normal occlusion.
The bases of the casts were kept parallel to th e occlusal plane that was established by including the tips of the mesio-buccal cusp of upper right and left second deciduous molars and the incisal edge of the upper left deciduous central incisor.
The standardrized photographs were taken 700 mm in front of the ca s t with Micro-Nikkol 105 mm lens and flash.
We Then measured t h e angle of inclination of the labial or buccal surface of the deciduous teeth in the lateral segment to the occlusal plane on the photographs.
The results were as follows:
1. In maxilla, the average of the angles of inclination were: 70.3° in left deciduous cuspid and 69.1K in right; 74.0K in left first deciduous molar and 72.8K in right; 72.4° in left second deciduous molar and 71.0° in right.
2. In mandibular, the average of the angles of inclination were: 70.6° in left deciduous cuspid and 71.8° in right; 55.1° in left first deciduous molar and 54.8° in right; 49.1° in left second deciduous molar and 49.2° in right.
3. The angle of inclination between left and right teeth revealed a positive correlation, and it also revealed to be nearly almost symmetrical in both sides.

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This study was to investgate the intial stage and the progress of carious invasion of the upper and lower primary molars. The materials were 341 primary teeth in total 98 upper first molars,103 upper second molars,63 lower first molars,73 lower second molars which had been extracted from children between the age of 6 to 14. The occlusal surfaces of each tooth were devided into 405 parts to observe the carious invas ion in each pit and fissure. The initial stage of the caries which was found to be a white spot or a colored spot.
The results w e r e as followes; 1) The initial stages of the caries on the occlusal surface were found on the distal pit of the upper primary molars and the lower first primary molars, and on the mes ial pit and the pit of the lingual groove of the lower second primary molars.2) There was a tendency for caries to spread faster on the bucco-lingual groove than on the mesiodistal groove.3) The direction of the carious progress was as follows.

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The purpose of this paper is to survey the influence of the nursery school period on dental caries prevalence in the deciduous teeth of nursery school children. The children studied here had finished nursery sdhool in March,1977 and 1978; they numbered 228 (128 boys,100 girls).
The children were cla s s ified into 4 groups according to the number of years spent in nursery school. The five-year group had attended nursery school continuously for five years from about the age of two. The four-year group had attended regularly for four years from about the age of three, the three-year group for three years from about the age of four, the two-year group for two years from about the age of five. The difference in the prevalence of dental caries in these groups was examined. The results obtained are as follows.
1. The prevalence of dental caries showed similar tendencies in the four groups. However, from an early period, the rate of def teeth in the five-year grou p was shown to be 7`10% lower than that in the other three groups.
2. The rate of def-teeth and def-surface teeth in the four-year group, which had been attending nursery school from about the age of three, showed higher values than the five-year group. Those values were similer to the values in the two and three-ye ar groups.
3. The decrease in the rate of def-teeth for the five-year group was more remarkable in the maxillary anterior teeth.
4. In the maxillary molars, the rate of def-surface teeth showed tendencies similar to that in the maxillary anterior teeth.
Although children spend o n l y about eight hours in nursery school, during this period at least there is limitation on the amount and number of meals or snac ks. The slow-down in the occurrence of caries in the five-year group can be attr ibuted to the influence of a correct, controlled diet from before the eruption of deciduous molars, if only for the nursery school period.

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It has been well known that some systemic diseases are the result frequently of primary affliction of oral diseases such as dental caries. However, it is hard to prove the relationship between the oral diseases and the systemic diseases. In many reports, those relationship were supposed by the fact that removal of foci of affliction in the oral region were followed by improvement of systemic diseases.
This study is a clinical case report of systemic erythema caused by dental caries of deciduous teeth.
A seven -year-old girl afflicted with systemic erythema underwent dental treatment in dental section of the National Children's Hospital. After ten deciduous caries teeth with apical periodontitis were removed by keeping in close communication with pediatric specialists, the systemic erythema disappeared and did not reappear.

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Ag (NH₃) ₂F has been shown to prevent dental caries and also depress the severity of dental caries in clinical surverys. However, this compoun d has the disadvantage of blacking caries or immature permanent teeth. From the results of both epidemiological surverys and animal experiments, molybdenum is also considered to be effective in reducing dental caries. Therefore, we have developed a new drug containing fluori d e and molybdenum, (NH₄) ₂MoO₂F₄, and examined its effects on the severity of dental caries in rats in comparison with Ag(NH₃) ₂F and acid phosphate fluoride (APF). The animals, fed cariesinducing diet 2000, were infected with Streptococcus mutans MT7038R (Serotype d)for 5 days. Four weeks after the first infection, (NH₄) ₂MoO₂F₄, Ag(NH₃) ₂F, APF or distilled water, used as a control, were applied to the lower molars of rats. The applications were carried out 8 times (once a week) during the experimental period. All of the animals were sacrificed 84 days after infection and t h e plaque and caries score were estimated. The results demonstrated no statistical difference in the increase of body weight among the infection groups. However, (NH₄) ₂MoO₂F₄ was demonstrated to depress the severity of dental caries to that observed with Ag(NH₃) ₂. Furthermore, (NH₄) ₂MoO₂F₄, in contrast to (NH₃) ₂F, did not blacken the molars.

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Supernumerary Deciduous teeth, shaped of Deciduous canine and enupted at the both upper incisal resions, was found in a boy of 3 years and 5 months old.
It is not rare for clinical pedodontics to survey the supernumerary teeth in the Deciduous dentitions. However, genuine supernumerary Deciduous teeth of them are very few. In fact, no more than 20 cases of surveys of genuine supernumerary primary teeth have been reported.
Dental formula of this case
From the position, erupted, the shape and size of these teeth, the age of the boy, and X-ray examination etc. we consider these as rare genuine supemumerawy deciduous canines.

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To make dental health guidance more effective at the time of Dental Health Examination for 1.6-Year-Old children, it is important that we understand the oral conditions and daily habits, especially dietary habits, of the children in this age group.
In this report, the oral conditions, the dietary habits and tooth brushing habits were surveyed and their relationships were examined. This survey was carried out on 531 children at the age of 1.6 years, visiting the Health Center in Ohta Ward in Tokyo.

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The subjects were 1710 children (890 boys and 820 girls), who visited the Pedodontics Clinic of Showa University Dental Hospital during the period from july 1977 to june 1979.
The purpose of this investigation was to understand the actual condition of the patients who visited here.
We investigated t he chief complaints, the ages and the place of residences of the treatment which they were treated in our clinic.

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This investigation was undertaken to evaluate diagnostic value of radiography concerning proximal caries of deciduous molars. Forty extracted deciduous molars were used for the study. Forty-seven proximal surfaces except those which were sound, filled and severly decayed were used for making inspective and radiographical examination. The early caries group were observed histologically after preparing the sections. After completion of this procedure, radiographical examination were compared with the inspective examination and the histological features.
The conclusions were as follows:
1. Concerning the early caries group, many cases showed a disagreement between the radiographical and the inspective examination. Therefore it seemed difficult to make a diagnosis of this group with radiographs. Histological features showed more progres sed lesions than did the radiolucent features.
2. On the other hand, the group which had caries lesions on the dentine showed conformity between the radiographical and the inspective examination. So, it seemed comparatively easy to make a diagnosis of this group.

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Odontodysplasia is a rare developmental anomaly in teeth formation which is generally found in young patients. This disease is characterized by the malformation and hypocalcification of both enamel and dentin, asymmetrically and locally. Rushton (1965)named it " Ghost teeth " because it showed a ghost like appearance roentgenografically. Although 50 cases have been reported in the world, there are few reports in Japan, and the causes remain unknown. This paper described a case of Odontodysplasia in a boy 1 year 11 months old with a chief complaint of swelling, bleeding and pain at the site of upper left anterior gingiva. The findings were as follows. Oral condition

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