Calcium is an important factor for adjusting remodeling of bone tissue. Its effect on the mandibular condyle during growth & development however has not been clarified.6-week-old male rats of Wistar strain were used, therefore, to investigate the effect of calcium on the mandibular condyle. Thirty rats were divided into three groups (The standard food group, low calcium group, and calcium deficient group).
The results were as follows:
1. The rats,6-week old, were divided into their respective groups and maintained until they were 12weeks-old. Results showed no significant differences found in any group concerning body weight.
2. The relative Ca quantitaive ratio and P quantitaive ratio were determined. Both relative Ca and P quantitative ratios showed almost same results between the standard food group and low calcium food group. However both the relative Ca and P quantitive ratios of the calcium deficient food group were lower, compared with the two former groups.
3. Based on the scanning electron microscope findings, the low calcium food group showed active formation of the longitudinal matrix and active formation of the trabeculae in the subchondral bone formation zone. When compared with the control group, every aspect was none or less satisfactory.

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The purpose of this study was to evaluate the meaning and effect of the health assessment which was performed by a nurse before, during and after extraction of impacted supernumerary mesiodens. The assessment tool was developed by the nurses of University Dental Hospital, The University of Tokushima School of Dentistry. In this study based on the record of the assessment tool, the unpleasant behavior such as crying and struggling, as well as the pulse rate, the blood pressure and pain just after operation were analyzed. The results were as follows. Some of the children who had deciduous upper central incisors or no eruption of the permanent upper central incisors showed crying or struggling, but it was for a short time and they did not show a change in pulse rate and blood pressure. Some of the children who had half eruption of the permanent upper central incisors showed anxiety or fear not by crying or struggling but in the change of pulse rate and/or blood pressure. It was suggested that the health assessment was very useful and that the information of the health assessment before, during and just after the operation given by the nurse to the dentist (operator) was very important for the prevention of anxiety or fear and conducive to good healing.

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To discover the characteristic dental treatment of handicapped patients, a committee of the Japanese Society of Pediatric Dentistry dealing with problems in dental treatment of handicapped patients sent a questionnaire to Departments of Pediatric Dentistry of the 29 dental colleges and schools of dentistry nation-wide, to universities and child centers with a division of dentistry for handicapped children, as well as to general practitioners randomly selected who were members to either of the Society of Dentistry for Handicapped Patients or the Society of Pediatric Dentistry. Items of the questionnaire included (1) name and location of the dental institution, (2) the year of establishment of the institution, (3) working hours of the clinic, (4) the number of chairs exclusively used for the handicapped patients, (5) the number of staff members, (6) the sexes and ages of handicapped patients, (7) details of the dental treatment, (8) methods of anesthesia treated, (9) use of restraining devices, (10) name of general diseases, and (11) residency status in institutions for handicapped patients. Responses to the questionnaire were obtained from 93 institutions involving 4,386 patients. The results of the questionnaire were analyzed comparativery among nine groups providing dental care including (1) Departments of Pediatric Dentistry, (2) Depatments of Dentistry for the handicapped patients, and (3) Departments of Oral Surgery in university/college hospitals, (4) hospitals of child centers, (5) hospital clinics for the handicapped patients, (6) public centers, (7) centers of the community of dentists, (8)general practitioners, and (9) others. We report here the detailed analysis of the comparative results.

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The ratio of female dentists in Japan is 14.8%, and the ratio of female members of the Japanese Society of Pediatric Dentistry's members is 37.8%. In a word, the ratio of woman is higher than the entire ratio of female dentists in pediatric dentistry. However, there had been little research concer ning the number of female dentists in pediatric dentistry.
To investigate how the female dentist influenced the child patient, child patient's eye movement was measured, and then the result was analyzed and examined.
Subiects were 37 child patients who came to the clinic of pediatric dentistry of Nippon dental university, school of dentistry at Niigata.
First of all, we made a test picture. The test picture assumed that the female dentist, subject's mother, and the dental hygienist entered the view of the subject in the lying on his back during dental treatment and we took a picture. We made the test picture for the video picture adding the voice by which the subject was talked to, the female dentist saying “Open your mouth”, subject's mother “Be good” and the dental hygienist “You did it”.
The test picture was presented to the subject as audio-visual stimulus, and subject's eye movement was measured with a visicon eye camera'.
The subjects were divided into the non-scanning group which did not see the person who was talking as did the scanning group which saw the person who was talking when three people were talking respectively, and the change in the eye movement by talking was analyzed based on the fixation point immediately before talking. Changes in the eye movement when the patient was being talked to were analyzed based on the fixation point immediately before being talked to. As a result, the following conclusions were obtained.
1. As regards the fixation point immediately before being talked to,24 subjects (64.9%) riveted their eye on the dentist and 13 subjects (35.1%) did not; 10 subjects (27.0%) riveted on the mother and 27subjects (73.0%) did not; 9 subjects (24.3%) riveted on the dental hygienist and 28 subjects (75.7%)did not.
2. Regarding the scanning group,28 subjects (75.7%) belonged to the dentist scanning group and 9subjects (24.3%) belonged to non-scanning group; 23 subjects (62.2%) belonged to the motherscanning group and 14 subjects (37.8%) belonged to the non-scanning group; 21 subjects (56.8%)belonged to the hygienist-scanning group and 16 subjects (43.2%) belonged non-scanning group.
3. Each scanning group increased in accordance with dentists, mothers and dental hygienist's talking, and a significant difference was recognized especially with the mother and the dental hygienist.
It has therefore been found that the child patient sees the person doing the talking, did the talking and child patient's eye movement to the female dentist in particular was not recognized.

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To investigate the visual response of child patients, when dental instruments are passed between the dentist and hygienist, we produced a video showing a dentist and a hygienist exchanging mouth mirrors and tweezers, and presented it to 39 infant subjects individually. Using the Visicon Eye-camera, we measured the eye movements of the children as they watched, for the sake of analysis. The findings are as follows:
1. When the mirror was being passed between the dentist and hygienist,20 children fixed their eyes on the dentist first,8 on their mothers at chairside, another 8 on other things,2 on the hygienist and 1 on the act of giving and taking the mirror. In the case of the tweezers,16 subjects looked at the dentist first,9 at other things,7 at the hygienist,5 at their mothers and 2 at the exchange.
2. As for number of times their eyes fell on the mirror as it was being exchanged, the handover action scored the largest number with 152 times, followed by the dentist with 135 times, other things with 51 times, the hygienist with 20 times and mothers with 3 times in that order. In the case of the tweezers, the handover action also came first with 334 times, followed by the dentist with 91 times, the hygienist with 37 times, other things with 15 times and mothers with 8 times.
3. Of the subjects,87.2% showed a reaction to the delivery of the mirror. Of this figure,76.5% reacted upon hearing the dentist speaking to the hygienist and 23.5% when theu saw the dentist's hand extending. In the case of the tweezers,97.4% of the subjects reacted, of which 92.1% reacted to the dentist's voice and 7.9% to the dentist's hand movement.
4. The percentage of the subjects whose eyes were caught by the mirror was 23.1%, of which 5.1%fixed their eyes on the mirror surface. The tweezers caught the eye of 25.6% of the children, of which 2.6% fastened their eyes on the tips of the tweezers.
From the above, we concluded that the children did not actually perceive the dental instruments visually. They reacted instead to the movement of the dentist and the hygienist as the mirror and the tweezers were being passed.

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An evaluation of the adaptation of the ceramic restoration for posterior primary teeth was carriedout by means of clinical and SEM observation immediately after placement of the restoration andevery three months for a period of two years.
Using the USPHS clinical evaluation criteria, and at a short observation period after the placementof the restoration, color matching (tooth - restoration), staining of the restoration margins, abrasion,marginal breakage and last of restoration showed favorable results. Body fracture of the restorationwas however found in two teeth out of the 14 observed.
After six months, some samples showed abrasion of the resin cement, while after 12 months, all ofthe teeth had some resin cement abrasion. After 15 months, Moreover marginal fracture of the restorationwas observed in two samples.
Based on SEM observation, immediately after placement of the restoration, the interface resin-cementand tooth could not be distinguished. This as the period elapsed, however from the placement ofthe restoration until the evaluation, being three months or more, the Image obtained from the replicashowed abrasion of the resin cement in all of the specimens. In addition, a slight marginal fracture ofthe ceramic was also observed.
After six months, fracture of the body of the restoration was observed in one specimen, usingSEM, though this finding was not confirmed by clinical observation. Furthermore, after six months,or more, slight marginal fracture was found in all of the specimens.
Based on these results, it can be said that the ceramic restoration was able to bring about very goodresults when used in primary teeth if only clinical evaluation is considered. However, using SEM observation,it can be seen that as time progresses, both ceramic-body fracture and abrasion of the resincement are observed. Probably in a longer observation period, due to the resin cement abrasion, marginalleakage would be found.
If the resin cement properties could be improved, such as its resistance against abrasion, the use ofceramic restoration in primary teeth could be suggested.

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This study was carried out to clarify the morphology of the root canal orifices using 86 human mandibular primary molars from several Chinese children within an age range of 3-8 years. After a dental X-ray was taken, and following removal of the roof of pulp chamber and pulpectomy, a silicone impression of the pulp orifice was obtained directly from the primary molars. By this means, an epoxy-resin replica was made and sliced at two points: 0.5 and 1 mm from the pulpal floor, respectively. Several variables were considered for the morphometric study of the pulp orifice such as width (mesio-distal distance), length (bucco-lingual distance), area, frequency and size of the concavity at the selected levels. The distance between the pulpal floor and the furcation area (thickness of the floor of pulp chamber ) and the mesio-distal width of each orifice, were measured using the X-ray films. The samples were divided into three groups according to age in order to findout any influence according to age. T-test and analysis of variance (ANOVA) was used for data analysis whenever appropriate.
The following conclusions were obtained:
1. The width (mesio-distal distance) of the pulp orifices in first primary molars showed a greater value at the mesial root than at the distal root, while in the second molars it was just the opposite. The values obtained by measuring the X-ray films were slightly greater than those obtained from the resin models. The length (bucco-lingual distance) in the first primary molar showed a smaller value at the mesial root than at the distal root while in the second primary molar the two values were similar. The area in both first and second primary molars, was smaller at the mesial root than at the distal one. The orifice seemed to taper to the apex as observed when comparing the obtained values at 0.5and 1 mm. The concavity of the root canal did not appear on the outer surface of the mesial root canal of the first primary molars and was more evident on the inner surface of the orifices of the each root canal. The size of the concavity was bigger on the inner surface of the orifices except in the mesial root canal of the first primary molars. There was no-aging influences except at the area in the mesial root of the second primary molars.
2. With regard to the influence of age, the thickness of the floor of the pulp chamber increased in both first and second molars. The size of the root canal orifices did not however change significantly. This could be explained by the coronal shift of the pulp orifices due to dentinal apposition in conjunction with age.
3. The obtained data in this study are of great importance when selecting the size of the instrument during endodontic therapy specially while pulpotomy is undertaken.

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The purpose of the present study was to investigate the effect of age on changes in the sulcus depth of healthy gingival young permanent teeth. We investigated 0.5 mm of the sulcus depth of children,99 boys and 132 girls aged 5-16, with respect to the mesial, center and distal side from the labial or buccal side of the maxillary and mandibular first molar, incisors. The results indicated that age and eruption effected changes in the sulcus depth as follows.
1. The sulcus depth developed a tendency to be deep on the mesial, center and distal side with increasing age and eruption, until 12-13 years of age in the molars and until about 10 years of age in the incisors.
2. The results of this survay suggest that the sulcus depth in children with healthy gingiva was 1.39±0.37 mm on the center and 1.50±0.37 mm on the mediodistal side in the maxillary first molar,1.16±0.46 mm on the center and 1.39±0.41 mm on the mediodistal side in the mandibular first molar, at 12-13 years of age. Its was 0.92±0.31 mm on the center and 1.27±0.55 mm on the mediodistal side in the maxillary central incisor of 10 years of age,0.69±0.28 mm on the center and 1.13±0.41 mm n the mediodistal side in the mandibular central incisor at 10-11 years of age. The sulcus depth woith healthy gingival was 0.93±0.39 mm on the center and 1.24±0.42 mm on the mediodistal side in the maxillary lateral incisor at 10 years of age,0.75±0.34 mm on the center and 1.17±0.43 mm on mediodistal side in the mandibular lateral incisor at 10-11 years of age.
3. The Center sulcus depth was shallowest on the mesial and distal side for the entire observation term.
4. Our findings suggested that sulcus depth of healthy gingival young permanent teeth were less than 3.0 mm.

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The purpose of present study was to clarify the effects of weaning conditions on the morophological and functional development of the jaw and muscle of guinea pigs.
Fifty hartley guinea pigs were used.3 days after birth they were divided into four groups as follows.
1) Control group: They were feed under normal conditions throughout the weaning period (breast feeded by their dam and solid-type food).
2) Solid-type food group: They were feed with solid-type food (RC-4® Oriental Kobo Co. ).
3) Soft-type food group They were feed with powdered RC-4®food.
4) Milk food group: They were feed with milk (Eva milk®, Nessle Co. ).
Experiment 1: Ten guinea pigs of each group were sacrificed by ether inhalation 40 days after birth. The masseter and digastric muscles were entirely removed surgically and then the wet weights were measured. For craniometric analysis, dry skull specimens were then prepared and measurements of the reference points were made. As a result, it was shown that the weight of both the masseter and digastric muscles of solid-type food group was heavier than those of soft-type food and milk food groups. The lower jaw of solid-type food group was bigger than that of soft-type and milk food groups, while with the upper jaw, there was no significant difference between the solid-type and soft type food group.
Experiment 2: From 17 days after birth, EMG of the masseter of the groups with solid-type and soft-type food were recorded with the guinea pigs eating by will with an interval of 5 days. The EMG of the masseter of soft-type food group showed no changes even as time passed, and showed a pattern similar to the drinking behavior. With the solid-type food group, regularity of the chewing rhythm and prolonged duration was noticed.
It was concluded that the weaning conditions may affect the development of jaw and muscles in guinea pigs.

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Osteomyelitis is a progressive infection of bone, usually of infectious origin, which tends to spread and instances may involve the entire bone. A prevalence of an osteomyelitis in children however, is very low compared with in adults. Recently, the general view is that sever dental caries in children have decreased and osteomyelitis of the jaws in children has been reduced in accordance with spread of using antibiotics. Nevertheless, some child and adolescent patients with osteomyelitis still visit the Okayama University Dental Hospital. The character of the changes that were produced in the bone of children with osteomyelitis was quiet different from that in adults. This article describes the radiographical and clinical features of osteomyelitis in children. The following results were obtained.
1) The age at occurrence of osteomyelitis was distributed equally among each age group.
2) Males showed a significantly higher prevalence of osteomyelitis than female.
3) Periosteum responses were found clearly in 61% of patients. This percentage was significantly higher than the 10% of the adult patients.
4) Forty four percent of the present cases occurred due to infection from a severely carious first molars in the mandible. Similarly,29% was occurred due to infection from primary posterior teeth.

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Two patients were diagnosed as having odontodysplasia at the pediatric dental clinic of Tsurumi University Dental Hospital. The process of the clinical approach, X-ray examinations and histological features of the affected teeth were presented. The results obtained were as followes:
1) In the first case, odontodysplasia was observed at region _??__??__?a?n_d in the second case at regions _??__??__??_ and _??__??__??_.
2) Developmental disturbances and hypocalcification of the enamel and dentin were found in both cases.
3) Histological findings revealed disarrangement of dentinal tubules in the coronal mantle dentin, but those of the radicular dentin appeared to be rather normal.

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The patient, a six year old boy was referred to the Pedodontic Department of Meikai University for a detailed dental examination of submerged of primary teeth. The oral findings through dental examination revealed that submerging of eight primary molars and severe attrition of the upper front primary teeth were occurred. According to radiographic examination, the cause of the submerged teeth was diagnosed as being induced by ankylosis. The masticatory dysfunction was treated with in overdenture and Electromyograms were recorded in order to evaluate changes in the masticatory function before and after treatment. The occlusal contact area of the total tooth and the occlusal force were also measured with Dental Prescal®. By having the patient wear an overdenture, the masticatory rhythm, synchronization on clenching, and the EMG activity of the masticatory muscles of the patient became better balanced. Silent periods during tooth tapping were noticed. The occlusal contact area and occulsal force showed an increse of six or seven times before using the overdenture.

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