There have been many studies on the calcified bodies in the pulp of the human permanent teeth however, little work has been done to study the calcified bodies in the human deciduous teeth. In the present paper, the result of histological study on the pulp calcified bodies in the human deciduous teeth is reported.
Fifty deciduous molars without dentin caries formed the basis of this investigation. The degree of their root resorption ranged from 1/2 to 3/4, and attrition of their crowns appeared in various degrees. After the decalcification, the teeth were embedded in paraffin, and 6μm sections were prepared for histological examination. The results were as follows:
1) True denticles which had tubular structures with irregular running were found in 7 teeth (14%), and true denticle were scattered multiply in 4 teeth (8%).
2) False denticles which had no tubular structure were found in 14 teeth (28%), and false denticles were scattered multiply in 10 teeth (20%).
3) Diffuse calcified-deposits which were one of the dystrophic calcification were found in 37 teeth (74%).
4) The true denticles demonstrated a constant incidence for all grades of attrition. The false denticles and diffuse c alcified-deposits, on the other hand, showed a high incidence in severe grades of attrition which revealed narrowing pulp cavity and atrophic changes of the pulp tissue in various degrees. The results of the present study suggest that calcified bodies in the pulp of the human deciduous teeth are not indeed rare.

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We reported that, in children with normal occlusion, the difference was found as to how masticatory muscles are used for mastication in deciduous dentition and in the permanent dentition. In a word, the temporal muscle works mainly in the deciduous dentition, while on the other hand, the masseter muscle works mainly in the permanent dentition. In cases of crowding, however, the functional development of muscles related to mastication which is one of the functions of the stomatognatic system not explained. This investigation was carried out for the purpose of estimating the masticatory function of muscles in cases of crowding.
The subjects consisted of 50 children with cases of crowding. They were divided into groups from IIA to IIIC according to Hellman's dental stage. The control consisted of 50 children with normal occlusion.
The muscles examined bilaterally were the anterior temporal muscles (TA), the posterior temporal muscles (TP) and the superficial portion of masseter muscle (M) utilizing four established movements such as gum free chewing, peanuts free chewing, marshmallow free chewing and maximum bite. After the actions of the above muscles were recorded using electromyography (EMG), the data was integrated. The TA%, TP% and M%, which are the percentage of the total action potential of TA, TP and M, were calculated to determine the quantity of the action between each muscle.
Concerning the results, we found, in comparison with the control, the decrease of the TA percentage and the increase of the M percentage were small with the advance of the dental stage in cases of crowding. Both in the deciduous dentition and in the permanent dentition, the anterior temporal muscle worked mainly in cases of crowding.

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The purpose of this study was the objective chromatical measuring of the primary teeth color of the Japanese children and the investigation of the effectiveness of the Color Difference Meter used in this study.
The normal primary anterior tooth colors of 30 Japanese children ranging from 2 years 4 months to 6 years 5 months of age (avarage: 4 years 3 months)were chromatically measured using the Light Guided Color Difference Meter CD-270 (Murakami Color Research Labo). The data was compared with that of the chromatical measuring of 18 Japanese children aged from 3 years 3 months to 6 years 6 months (avarage: 5 years) using the Color and Color Difference Meter 1001 DP (Nippon Denshoku Co. ) which were reported on previously.
The following results were obtained.
1) Precise chromatical measuring of the primary tooth colors in the oral cavity is available using the Light Guided Color Difference Meter CD-270 which has the filters for intercepting the influence of the light from the outside of the light guide head, and is also able to measure the chromaticity in instantaneously.
2) The mean chromatical values of XYZ, and L measured with the CD-270were higher than those measured with the 1001 DP.
3) The mean chromatical values of a b of all kinds of primary anterior teeth measured with the CD-270 were plus values and showed a reddish-yellowish color, while the values measured with 1001 DP were almost zero and showed an extremely white color and there was little difference among the kinds of primary anterior teeth.
4) Since the diameter of the light guide head is 7 mm, it is too big for chromatical measuring of primary anterior teeth, the data of L a b was in danger of being influenced by the gingival color in the cases of the CD-270. In the cases of the 1001 DP, the data of L a b was in danger of showing only enamel surface color or only the value of L. There remains the question of not being able to detect the particular primary tooth color.
5) The diameter of the light guid head of CD-270 should be made into a smaller size.

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The design of cavity preparation for primary teeth including depth, width etc. affects the falling out, breakage of material, break kown of the tooth and sensation of pain caused by the pulp. With this in mind, a study using the finite element method was made to analyze the change and stress of the restorative materials and the tooth itself.
For the two dimensional finite element model for the primary teeth, the bucco-lingual section of the crown of the lower second primary molar was used as a standard. The cavity preparation was class 1 on the occulusal surface, width.0.9 mm and 1.5 mm depth 1.0 mm,1.5 mm and 2.0 mm. The cavity was prepared with a 330 carbide rounded angle bur. Restorative materials used were composite resin, amalgam and metal inlay. The displacement and stress figures were made. The analysis was done for displacement of each point and the relative stress in the principal area.
The following conclusions were obtained.
1. The deeper and wider the cavity preparation was, the lower was the displacement around the restoration. The metal inlay was the lowest in displacement.
2. The deeper the level of composite resin and amalgam, the more was displacement noticeable on the pulp. Conversely, the metal inlay was found to have a lower displacement at deeper levels.
3. Stress in the restoration was higher than in the control and stress was concentrated in the restoration. However stress in the rest of tooth was lower.
4. Stress directly under the restoration with composite resin and amalgam material was higher, but with the metal inlay it was found to be lower.
5. Stress in the pulp was so low that pain would not normally occur.

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The purpose of this study was to clarify the conditions of the types of the oral habits in the children, and changes in them during the last ten years.
The investigation was made based on the records of the first visit to the Department of Pedodontics, School of Dentistry, Aichi-Gakuin University, taken from 0 to 10 year old children, from 1976 to 1985.
Oral habits in this study were classified into 5 species (1: Finger sucking,
2: Bruxism,3: Nail biting,4: Lip biting,5: Other biting).
The results were as follows:
1) The number of the children who had any oral habits was 1596 out of 4159(38.4%).
2) The types of oral habits were as follows:
Finger sucking: 20.0%
Bruxism: 7.0%
Nail biting: 7.8%
Lip biting: 2.1%
Other biting: 4.6%
3) Concerning the relationship between oral habits and age, finger sucking was found more evident in the 0 to 1 year old group, nail biting was found most evident in the 9 year old group, bruxism was found more appearance in the 4 to 6 year old groups, other biting was found gradually to disappearance in the 0 to 8 year old groups, and lip biting was not significant in any age group.
4) The type of oral habit was closely related to each age group of the children. Finger sucking tended to decrease with age. Nail biting and bruxism tended to increase with age, and lip biting and other biting showed no relationship to age.
5) Few over a ten year period changes were noticed in the percentages of the types of oral habits among the children having such habits.
6) The changes of each oral habit over ten years were as follows:
(1) There was found to be a tendency towards increases in such types as finger sucking and nail biting in the 3 to 6 year old groups, and nail biting and bruxism in the schoolchildren groups.
(2) There was found to be a tendecy towards decreases in such types as nail biting and other biting in the 0 to 3 year old groups, lip biting and other biting in the 3 to 6 year old groups, and finger sucking and lip biting in the schoolchildren groups.

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In 56 cases of traumatized immature permanent maxillary central incisors requiring endodontic therapy, root apexification was induced with 3 kinds of Calcium Hydroxide pastes.
22 teeth were filled with Calcium Hydroxide-distilled water paste (group C), and 15 teeth were filled with Calcium Hydrixide-CMCP paste (group F), with replacement of paste every 3 or 4 months.18 teeth were filled with“VITAPEX”(group V), with the“VITAPEX”removed within 2 years and 9 month.
These cases were observed clinically and radiographically, and the mean observation period was 3 years 8 months. The following results were obtained.
1) In the C group and the F group (except in 1 tooth), apical closure was observed in 3 years and 1 month. Apical closure of these teeth seemed to be influenced by the condition of the root canals and degree of the apex width at the start of apexification. The wider the root apex is at the start of apexification, the later the apical closure tended to be observed.
2) In the V group, radiographical apical closure was observed in 15 teeth, but apical closure by formation of hard tissue were observed in only 4 teeth. The partial disappear of the roentgenographic opacity of“VITAPEX”was observed in many cases.

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The purpose of this study is to suggest the examination of a method of the changing quantitative analysis which the polygraph indicates for the dental treatment of patients with inhalation sedation of nitrous oxides gas. We selected 8persons who were healthy adult men from 20 to 24 years of age. The process of sedation with nitrous oxide gas which we used was at first the inhalation of pressure air with face mask with a capacity 8 litter per minute for 4 minutes, then, changed that air to 30% N₂O and 70% O₂.
The outputs of the polygraph were the electroencephalograph at front head, the horizontal electrooculograph, the electromyograph on the muscles mentalis and the respiration rate.
We transmitted these outputs from the dental chair. We calculated these outputs with the computer immediately, and analysised for one minute the power rate for the electroencephalograph with each cycle, the frequency of the electrooculograph, the integrate rate for the electromyograph.
The result showed a contrasting rate for the inhaltation with pressurized air for one minute:
1) The power rates significant decreased on the θ wave and α wave within 9minutes after starting the inhaltation with nitrous oxide gas, and then, β wave increased significant. These two changes was brief.
2) The frequency of electrooculograph significant decrease between 3 minutes and 9 minutes after the inhaltation with nitrous oxide gas.
3) The integrate rate did not show significant change, but had an inclination to be stable after 10 minutes after the inhaltation.
4) The respiration rate was stabilized with the inhaltation with nitrous oxide gas.

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The purpose of this study was to evaluate the reproducible of the FFT analysis for the EMG activities of the masticatory muscles. Three children (II A- II C) and three adults who have normal occlusal function were subjected. The EMG recordings were taken during positions of resting occlusion, clencing and tooth tapping of the subjects. Three parameters were chosen for the measuring points such as 1) frequency range (Hz),2) frequency of maximum peak (peak Hz),3) strength of maximum peak (peak dBV).
The results obtained in the present sudy were summarized as follows;
1) The two parameters such as frequency range (Hz) and peak (dBV) were found to be reproducible in the children and adults alike, while peak (Hz) showed some varieties within single day and day by day basis.
2) With increasing the biting force, the values of frequency range (Hz) and peak (dBV) also showed a tendency to increase, and when it was compared with the temporalis and masseter muscles, the temporalis muscle showed superior activities in children, while, the masseter in adults.
Although the discussions are still left if the measuring point adopted in the study is adequate. From the results obtained in the present sudy suggested that FFT analysis was considered to be effected method for evaluaing the activities of masticatery muscles both in children and in adults.

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The purpose of our study was to investigate the reliability of the E. I. A. S-IgA test (made by M. B. L. ) and the circudian rhythm of secretory IgA (S-IgA)concentration, the S-IgA/albumin ratio, S-IgA/total protein (T. P. ) ratio in whole saliva of healthy people. Whole saliva was collected from 51 children and 42adults. Parotid saliva was collected from 27 adults. Concentration of S-IgA and S-IgA/T. P. ratio were measured. The results were as follows.
1) High reliability on the E. I. A. S-IgA test was confirmed by use of the dilution test, the recovery test, and the repeatability test.
2) We limited the conditions for collecting the saliva severely, but the circudian rhythm of the concentration of S-IgA in saliva was large. The S-IgA/albumin ratio was not suitable to minimize the circudian rhythm of a concentration of S-IgA, but the S-IgA/T. P. ratio was suitable.
3) Concentration of S-IgA in the saliva of children (age 3-6) was significantly lower than in that of adults. The same results were found in the case of of the S-IgA/T. P. ratio.
4) A significant difference between male and female of children and adults was not found in concentration of S-IgA and S-IgA/T. P. ratio.
5) There was no correlation of the concentration of S-IgA between whole saliva and parotid saliva, and the concentration of S-IgA as well as the S-IgA/T. P. ratio was significantly high in whole saliva.

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1) We encountered a case of impacted E and consequent malpositioning of the succeeding permanent tooth germ and congenitally missing tooth germs for 3|3 in a girl, six years old at first examination.
2) The patient's medical history and family record were uneventful and the cause of development could not be clarified clinically.
3) Histopathological investigation of the extracted E showed formation and close cementing of osteoid tissue in the resorption lacunae of the dentin at the root region. Ankylosis was confirmed.
4) Marked degenerative changes such as hyaline degeneration and the calcareous degeneration were observed in the pulp tissue near the floor of pulp chamber where ankylosis was observed.
5) Judging from the findings of the histopathological investigation, the probability of infraclusion of the deciduous tooth could not be excluded; that is, E had erupted and remained submerged for some reason and was enclosed by the surrounding tissue.
6) An observation on a scanning electron microscope of the cementum and dentin of E showed resorption lacunae of various sizes.

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We conducted a survey to investigate the actual status of dental treatment for handicapped patients by sending questionnaires to 295 dentists who were Local Kinki members of the Japanese Society of Pedodontics. There were altogether 97 replies. The results of the survey were as follows:
1) The actual frequency of the total replies of handicapped patients visiting dental offices was reported“often”in 16%,“sometimes”in 60% and“rarely”in 24%. Concerning their handicapped conditions, mental retardation had the highest prevalence followed by cerebral palsy, autism, heart diseases, deafness, blindness, cerebral hemorrhage and spinal damage. The reason for their attendance was mainly that their family had been visiting the same dentists.
2) Considerations regarding handicapped patient care, the design of the clinic and length of the appointment time had been rather neglected. Concerning the difficulty in attendance by patients using wheelchairs,48% of the respondents reported“no problem”in the design.70% replied that they had installed special equipment such as restrainers and instruments such as mouth props.
3) As for the dentists' consciousness and attitudes of treatment towards handicapped persons,95% of dentist showed knowledge and understanding regarding the attitude of treatment towards handicapped patients. Patient with only“mild”disorders were treated in a manner similar to normal patients. However in the case if“severe”patients, the quality of treatment would deteriorate and the proportion of referals to other medical institutions became higher.
4) As for clinical experiences and training in dentistry for the handicapped at other medical institutions,70% of dentists answered that they had such clinical experience and 55% had received special training.
5) As for university education and the role of the university hospital in relation to dentistry for the handicapped, the majority of the dentists answered that dentistry for the handicapped should be included in the students' curriculum and the university hospital should play the role of tertiary medical institution.

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In the present report, three patient ranging from 6-7 years of age, with mandibular dentigerous cysts which may be caused by apical periodontitis of the deciduous molars are presented. A marsupialization was made concerning the dentigerous cysts and postoperative follow up observation was made. Guiding and inducing the eruption of the permanent premolars from the cystic cavity were accomplished with the aid of removable space maintainers and closure of the cyst was interfered in 2 cases out of three.
The results obtained from these operations and observations were as follows; the cyst sac disappeared 10-14 months after the operation, and the directions of the erupting premolars became normal in 2 cases, although buccal inclination was shown in one case. Brown or white capped crowns of the erupting teeth were observed, and these discolorations were considered to be caused by enamel hypoplasia due to periapical infections of preceding deciduous molars, or may be caused by plaque accumulation associated with the space maintainers. Curved root formations were also characteristic, and this may be considered presumably to be caused by increased internal cystic pressure.

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