To examine how pediatric dentistry is fundamentally tackling caries prevention, and caries control for infants, we conducted an investigation using questionnaires from the department of pediatric dentistry of the 29 dental universities in December,1998.
1. Concerning parents education, private guidance is more important than group guidance. The instruction mainly focused on oral cleaning and eating between meals, while private guidance is being carried out to meet the individual condition of the infant.
2. At each university, the application of the fluoride was carried out actively and also diamine silver fluoride solution was used as the caries control medicine by patients of infants below 3 years of age. There were many universities which applied fluoride containing sealant to pit and fissure sealing.
3. Most of the departments of pediatric dentistry gave instruction concerning eating between meals, brushing, tooth brushing using floss, and the application of the fluoride and sealant to pit and fissure sealing. Also byte wing projection of X-ray examination, plaque score calculation, caries activity test were carried out in about half of the universities.
4. Concerning the handing of uncooperative children in the various departments of pediatric dentistry, it was found that the intervals between the periodic examinations was kept short. Instruction concerning oral cleaning was carried out in the presence of the parents and focused on caries prevention. Each university considered PMTC(Professional mechanical teeth cleaning) effective and most of them did carry out PMTC. Prevention of caries using computers or lasers was not applied due to the expense involved.

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The purpose of the present study was to investigate the change in the coordination pattern of the perioral muscles from the temporalis (TM), masseter (MM), orbicularlis oris (OM) and suprahyoid muscles (SM) in the sucking cycle during breast feeding in infants after birth from one to six months and the weaning period, and to discuss the differences between breast and artificial nipple feeding.
A total of sixty-two infants were innvolved in the study. For the EMG parameters, the sucking cycle time (ms), the peak amplitude (μV⋅s), and the peak time (ms) and the peak time ratio (%) which were measured from the onset of the sucking cycle to the point of the highest amplitude of each muscle activity on the EMG mean integration curve, were examined.
The following results were obtained:
1) The mean sucking cycle time of the breast-fed infants was 632.3 ms, while there were no significant differences among the number of months after birth.
2) Based on the peak time and the peak time ratio analysis, it was found that the TM, MM, OM were activated in the first half and the SM was activated in the latter half of the sucking cycle. For the order of the muscle bursts were the TM and OM activated first followed by the MM and SM.
3) There were no significant differences in the sucking cycle time and the peak time between the breast and artificial nipple feeding.
4) The peak amplitude of the SM was generally the highest, followed by the OM, the TM and the MM during both the breast and artificial nipple sucking.
It was concluded that the stable coordination pattern of the perioral muscles was recognized in the sucking cycle and the coordination pattern was not influenced by either the number of months after birth and the type of nipples.

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The purpose of the present study was to investigate the characteristics of mastication in infants by evaluating the electromyographic coordination pattern of the masticatory muscles and VTR and to discuss the development of the mastication in infants from sucking or weaning to adulthood with maturated chewing. A total of eighty-nine subjects were divided into the following seven groups, the sucking group (G 0: as a control,23 subjects), G 1 (6 to 7 months in age,14 subjects), G 2 (8 to 9months,14 subjects), G 3 (10 to 12 months,8 subjects), G 4 (1 to 2 years,7 subjects), G 5 (3 years,13 subjects) and G 6 (adults,10 subjects). The transition of the coordination pattern of masticatory muscles (TM: temporal, MM: masseter and SM: suprahyoid muscles) while ingesting cooked rice as a test food were analyzed.
When compared to the G 0, both the chewing cycle time and the burst duration measured in the TM became significantly longer throughout G 1 to G 3, and then the values gradually declined in G 4to G 6. The coefficient of the variation in the chewing cycle time was higher in G 1 to G 3 than that of G 4 to G 6. The masticatory pattern for the weaning period infants were characterized by the coincidental activation of the TM and SM. The mastication pattern of infants, therefore, can be classified into three types, such as the continuous tongue compression (Type I), the cyclic tongue compression (Type II) and the maturation type (Type III). The fequency of Type III significantly increased from G 1 (1%) to G 6 (74%), while the Type I significantly decreased, especially after G 4.
As the coincident of the bursts of the TM and the SM was recognized during each chewing cycle in the earlier period of weaning, food was considered to be ingested by the active movement of the tongue around this period. The development of chewing in terms of the EMG coordination pattern for the masticatory muscles, therefore, disclosed that the function of the jaw closing muscles and of the SM differentiated gradually as the time proceeded from the initiation of weaning. The turning point for the phenomena is considered to exist between G 3 and G 4.

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It is an obvious fact that dental caries contribute to a worsening of the occlusion function. Considerable restoration was required considering the influence of normal growth of the masticatory organs on function and morphology. In the present study we used the caries severity index (CSI) to classify deciduous dentition into the groups CD_0-6. Regarding the influence of caries on the development of the occlusion during infancy, an investigation of the occlusal contact area, occlusal force, and average occlusal pressure evaluated with type R DENTAL PRESCALE® 50-H led to the following conclusions.
1. The occlusal contact area was significantly larger in groups CD₀ and CD₁ than in groups CD₃, CD₄, CD₅ and CD₆. Moreover, the corresponding value in group CD₂ was also significantly higher than in the groups CD₃, and CD₆.
2. The occlusal force in groups CD₀, CD₁, and CD₂ was significantly higher than in the groups CD₃, CD₄, CD₅ and CD₆.
3. Regarding average occlusal pressure no statistically significant differences were observed among the various groups.
The results suggest that occlusal contact area and occlusal force decrease with an increasing CSI. The decrease in both occlusal contact area and occlusal force was particularly evident, when the CSI exceed 10. Thus, while prevention of caries is given course, caries must be treated as early as possible to approach the physiologic occlusal development.

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Streptococcus mutans (S. mutans) has been implicated as a primary causative agent of dental caries in humans. S. mutans may bind on to dental pulp cells, there by inducing progressive caries. In this study the author investigated how S. mutans is related to the cell death of human dental pulp. The author of the present study furthermore examined whether or not S. mutans causes apoptosis.
Cells were cultured for 48 hr using serum-free medium with S. mutans. Cytotoxicity was tested on the cells with the MTT assay, the LDH assay and the BrdU assay. The induction of DNA fragmentation of the cells was examined with ELISA, agarose electrophoresis, and flow cytometric analysis. Cell death induced by S. mutans occurred via apoptosis, increased fragmented DNA, and the typical ladder pattern of DNA fragmentation indicative of apoptosis.
These findings suggest that S. mutans causes apoptosis in pulp cells, indicating that S. mutans contributes to the initiation of infection of pulp in vivo.

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Developmental and growing differentiations of the microstructure and connective tissue core (CTC)of the fungiform papaillae in neonatal rats born to methamphetamine-dependent mothers were investigated utilizing the epithelial exfoliation method with scanning electron microscopy.
In the experimental group, three newborn rats receiving a dayly hypodermal injection of methamphetamine after vaginal plugging were used 1 week,3 weeks and 5 weeks after birth, respectively. In the sham group, newborn rats injected with the saline solution were used for the same periods.
One week after birth, fungiform papillae which appeared as round dome-shaped features and differences between the sham and experimental groups were not obvious.3 weeks after birth, CTCs of the fungiform papillae in the experimental group were indicated as being more slender on top than the ones in the sham group.5 weeks after birth, atrophic structures were recognized on the microstructure and CTC on the fungiform papillae.
In this study, it was revealed that the drug habit has a baneful influence upon the development and growth of the oral tissuses and might also induce these dysfunctions.

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The purpose of this study was to examine whether it is an effective way to reduce damage for enamel surface, and to give patients a pain as light as possible while removing metal brackets with a CO₂ laser.
The results were as follows;
1) The setting of the optimal laser irradiation to remove brackets effectively was an output of 2 watts laser, pulse time of 20 msec,20 pulse per second with normal pulse. This laser irradiation for 4 seconds could remove brackets effectively without damage to the enamel surface structure.
2) It was found by SEM observation that the bonding agent became softened with the heat of the laser irradiation. Changes were also not recognized on the enamel surface around the bracket base.
3) There were no recognized remarkable changes in the pulp of the tooth found during histological observation after the metal brackets were removed with the CO₂ laser.
It is suggested that this is an effective way of removing brackets without enamel damage and harm to the patient. However, as the laser reflection on metal exists, the angle of laser irradiation is taken into consideration. As the state of the surrounding tissue is secured, removal of brackets must be conducted. Also, when the laser was not well irradiated at the bonding agent between the enamel surface and the bracket, it took quite a long time. These were, therefore, the items which we recognized as still requiring improvement.

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One hundred and six handicapped children who underwent dental treatment in Funabashi Sazanka Dental Clinic during the past five-year period were evaluated retrospectively. Moreover, questionnaires were sent to the guardians of handicapped children in Funabashi City, and we investigated the actual state of their dental environment.
The results are summarized as follows:
1. The children who had been treated in Funabashi Sazanka Dental Clinic were between 3 and 18 years of age with a mean age of 7 years and 9 months. There were 73 males and 33 females. The residence of the patients was spread all over the city and there seemed to be no deviation in distribution.
2. Of these children, mental retardation was the most common disability (30.2%), followed by autism (27.4%), and the Down syndrome (11.3%), while others had a combination of these complications. The major reason for the visits was treatment of dental caries.
3. Restorative and periodontal treatment was the most frequent among dental procedures. Meanwhile, the extraction of teeth accounted for less than 10 per cent of all of the treatments. Three of the four children were recalled for periodical examination.
4. More than half of the patients was treated with the physical restraint appliance. About 10 per cent of the children were referred to the special clinic of university for treatment under general anesthesia.
5. The questionnaires were sent to 464 guardians of handicapped children and 264 of them were returned (56.9%). More than 80 per cent of guardians responded that their children had experienced dental therapy, and the majority of the children had consulted a general practitioner.
6. Public services handling information for the handicapped seemed to be of little help because most of the guardians obtained the information from acquaintances who had the same kind of disorder.
7. Regarding the demands for dental service,31.9 per cent expected oro-dental examination, followed by caries treatment (31.1%), preventive care (15.7%), scaling (11.9%), etc. It is considered that the guardians of handicapped children were deeply concerned not only about dental caries but also oral health in general.

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The vitality of the tooth pulp in children has been mainly determined by the response to painful stimuli such as to electrical and thermal ones. In the present study, we recorded transmitted-light photoplethysmography (TLP) from the dental pulp in children and examined its applicability to the pulp vitality test. The upper central incisors of one adult (n=2,26 y) and six children (n=12,6 healthy and 6 traumatized,6 y-12 y) were used for this investigation. Prior to the measurement, the purpose and procedure of the present study were explained to the subjects and their parents and informed consent was obtained. A resin cap of the examined tooth was prepared on the plaster model of the upper arch of the subjects. A green light-emitting diode (LED, peak power at 525 nm) illuminated the palatal surface of the examined tooth via an optical fiber attached to the individual resin cap, and the transmitted-light through the pulp was picked up from the labial surface of the tooth. The intensity of the transmitted-light was guided to a CdS photoconductive cell (peak sensitivity at 550 nm), and its intensity change was recorded as TLP through an AC-coupled amplifier together with the finger plethysmography of the subjects. Recordings were made with and without an opaque black rubber dam application in a dark room. TLP signals were afterwards averaged and their amplitudes were obtained using a signal processing software. In one subject,2% lidocaine solution containing 1/80,000epinephrine (2% LE) was periapically infiltrated and the transition of the amplitude of the TLP was observed. The results obtained were as follows: 1) TLP, synchronous with the finger plethysmography, was recognized from sound permanent teeth of an adult and the young subjects. The signal amplitude of the TLP was larger and the waveform was much far clearer with the young subjects.2)TLP was recorded slightly from luxated teeth which did not respond to electrical stimulation to the pulp. With an implanted tooth, however, no obvious pulse wave was detected.3) The dam application did not produce a significant signal reduction.4) Periapical infiltration of 2% LE produced a gradual decrease of the amplitude of TLP and then was followed by an increase. Results indicated that TLP is considered to reflect pulpal haemodynamics and this system would be useful for the diagnosis of pulpal vitality of the young permanent teeth without eliciting any sensation of pain.

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Experimental fiber-reinforced resin splint materials were prepared, and the fluoride release and their mechanical properties were evaluated. Methacryloyl fluoride-methylmethacrylate copolymer (PMF)was incorporated into the resin splint as the fluoride releasable source, The results were as follows:
1) The transverse strength and elastic modulus of the resin splint did not change after being imersed in water for two weeks.
2) The amounts of fluoride measured were higher on the first day and they gradually showed a decrease for 3 weeks. The amount of fluoride released was dependent on the type and amount of PMF.
3) The stickiness of the resin splint had a much lower adhesive strength than that of commerciallyavailable resin composite.
4) The resin splint showed a higher bond strength to the etched enamel (approximately 18 MPa) with cohesive fracture of the bonding agent and/or resin splint.
5) The resin splint showed a lower hardness than the resin composite.
6) The abrason loss of the resin splint with the fissure bar instrument was greater than that of the resin composite.

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A study was conducted in order to estimate objectively physiological tooth mobility in young permanent teeth.
The subjects in this study were 98 maxillary central incisors and 73 maxillary lateral incisors of patients between 6 years and 9 months old and 13 years and 8 months old. The teeth were clinically normal. These teeth were classified into 3 groups by their degree of root development. We measured tooth mobility using the “Dental mobility checker®”.
The results were as follows: Among the central incisors, at Stage I, the mobility value was between 2.3 and 5.0 (average: 3.32). At Stage II, the mobility value was between 2.2 and 4.3, (average: 2.91), and at Stage III, the mobility value was between 1.8 and 3.5, (average: 2.76). There was a significant difference in tooth mobility between Stage I and Stage III (p<0.01) There was a significant difference in tooth mobility between Stage I and Stage II (p<0.05)Among the lateral incisors, at Stage I, the mobility value was between 2.4 and 3.8 (average: 3.18).
At Stage II, the mobility value was between 2.1 and 3.9 (average: 3.00), and at Stage III, the mobility value was between 2.1 and 4.3 (average: 2.77). There was a significant difference in tooth mobility between Stage I and Stage III (p< 0.05)
In conclusion, it is suggested that is estimated objectively physiological tooth mobility in young permanent teeth can be evaluated using the “Dental mobility checker®”.

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Sucralose (trichlorogalactosucrose) is an intensive sweetener which is synthesized from sucrose. The effects of sucralose on the acid production and glucan synthesis from sucrose were examined in vitro. Streptococcus mutans and related oral streptococcal species did not ferment sucralose. Furthermore, sucralose exhibited no significant inhibition of insoluble glucan synthesis from sucrose by GTase of S. mutans or sucrose-dependent cell adherence of S. mutans on the smooth surface. These results suggest that sucralose may be used as a low-calorie and non-cariogenic sweetener.

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Through a comparative study based on questionnaires, we endeavored to discover the extent of the relationship between the memory of dental treatment received during infancy (pre-school) and later attitudes towards dental treatment. The 350 subjects used in this survey were 4-to 6-year old students of the dental department of our university.
The results were as follows.
1) Those who were able to remember receiving dental treatment as a child (pre-school) accountied for 61% of the total subjects, but only 10% of all the subjects were able to recall their attitude toward the treatment at that time.
The above findings indicate that the majority have only a vague recollection of past dental treatment.
2) Those who had experienced repression treatment in the past and still clearly felt apprehensive and worried about dental treatment, amounted to 18% of all of the subjects, whereas only 5% felt apprehensive or worried about dental treatment who had not experienced such repression treatment. There was a difference of more than 10% between these two groups. On the other hand, there was a difference of over 10% between those who had experience repression treatment but did not feel apprehensive or worried when treated now (16%) and those who had neither experienced repression treatment nor felt apprehensive or worried now (28%).
Based on the X² statistical test, no significant differences were found but there was a tendency for those who had experienced dental treatment in the past to feel more apprehension and worry today than those who had not had such experience.

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The aim of this survey was to determine the relationship between osteoporosis prevention related attitudes, habits in daily life since childhood, medical histories and radius bone mineral density (BMD) by DXA (dual-energy x-ray absorptiometry). The subjects of the study were 48 female college students, living in the city of Kitakyushu, Fukuoka. Data on dietary habits, physical activities, osteoporosis prevention related attitudes and a focused history were collected by means of selfadministered questionnaires. These data suggested that:
1) there was a tendency in which students having had, either the traditional Japanese style or the well-balanced style of eating habits since childhood, had a higher BMD. The association between the traditional Japanese style eating habit and BMD was significant.
2) the group with histories of bone fractures or weight-loss more than 3 kg per month until 15 years of age showed a lower BMD than the other group.
3) a significant correlation was noticed between the positive osteoporosis prevention related attitude and the BMD. Most of the osteoporosis prevention related attitudes was associated with calcium intake.
4) the present study revealed that giving young people instruction about habits in childhood and health education in order to stimulate osteoporosis prevention related attitudes would be affective in preventing osteoporosis later on in life.

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This article describes four cases having submerged primary teeth in the mixed dentition and mesial inclination of the first permanent molars adjacent to these teeth, which caused a space shortage for eruption of the succedaneous permanent teeth. Space regainers were utilized for up-righting the first permanent molars and creating the space for eruption of the submerged primary teeth and consequent eruption of the succedaneous permanent teeth. Longitudinal clinical evaluations using the X-ray pictures and the study models were performed on these four cases to verify the space regaining for the submerged primary teeth.
The following findings were obtained.
In Case 1, the submerged upper left second primary molar re-erupted to such an extent as to obtain the occlusal relationship with the antagonistic tooth after up-righting the adjacent first permanent molar. In Case 2, the submerged upper left second primary molar re-erupted up to the whole exposure of the occlusal surface after up-righting the adjacent first permanent molar. In Case 3, the submerged teeth were the lower left first and second primary molars. After up-righting the first permanent molar, the root resorption of these teeth were observed with the development of the succedaneous permanent teeth which erupted in the normal position of the dentition. In Case 4, the bimaxillary left second primary molars were severely submerged, and the mandibular second primary molar was completely embeded. During the space regaining for these teeth, the upper second primary molar exhibited some extent of pre-eruptive movement with the succedaneous permanent tooth, and root resorption of the lower second primary molar was observed in accordance with development of the succedaneous permanent tooth.
In summary, these observations suggest that the submerged second primary molars in the mixed dentition period should be treated with the space regaining procedure involving up-righting the adjacent first molar, since this facilitates re-eruption of the submerged primary molars as well as eruption of the succedaneous permanent teeth.

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A case of the XXXXY syndrome, in which 3 excess X chromosomes are present in the male, is described with dental findings.
1. The patient had a history of retarded intrauterine growth and was born with vaginal cephalic delivery after a pregnancy of 39 weeks and 4 days. The state at birth was neonatal asphyxia with Apgar scores of 3 (1 minute) and 5 (5 minutes).
2. The neonate showed pulmonary valve stenosis, hypospadias, split scrotum, pes varus of the left foot, retarded mental and physical development, and poor body weight gains as complications.
3. The state of ossification of the carpal bones was nearly in agreement with the chronological age. X-ray films revealed taurodontism of the first deciduous molars.
4. Analysis of lateral roentgenographic cephalometry of the head indicated a generally small skeleton, a slightly large length of the mandibular body, a small height of the rami of mandible, and clockwise rotation of the mandible.

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