The purpose of this study was to investigate the influence of the light-irradiation times on the bonding agent on the adhesion of the resin to the primary ground enamel.
Labial surfaces of 60 extracted and frozen bovine mandibular primary incisors were used. The bonding agent and composite resin used in this study were Photo Bond and US shade color Photo Clearfil A (Kuraray Co. ). The etchant used in this study was 40% phospholic acid gel and the etching time was 30 seconds. Light-irradiation times for the bonding agent were 10,20 and 30 seconds and the light-irradiation time for the composite resin was 40 seconds. Specimens were divided into the non-thermal cycled groups and the thermal cycled groups. In the thermal cycled groups, thermal cycling tests consisting of water baths with 10,000 temparature cycles between 60°C and 4°C were attempted. The shear bond strength was tested. After the shear bond strength test, the test surfaces of the enamel and the resin specimens were observed using the SEM.
The following conclusions were obtained.
1) In the non-thermal cycled groups, the bond strength with 10 seconds (80.10±13.01 MPa) of light-irradiation on the bonding agent was significantly higher than those with 20 (45.35±16.24 MPa) and 30 seconds (49.91±8.58 MPa)of light-irradiation times.
2) In the thermal cycled groups, the bond strength with 10 seconds (78.99±10.93 MPa) of light-irradiation on the bonding agent was significantly higher than that with 20 seconds (56.85±14.94 MPa) of light-irradiation time. However, there was no significant difference between the bond strength with 10seconds of light-irradiation and the bond strength with 30 seconds (67.31±16.78 MPa) of light-irradiation.
3) In the case of 30 seconds of light-irradiation time on the bonding agent, the bond strength with the thermal cycled group was significantly higher than that with the non-thermal cycled group.
4) Higher bond strength was not always obtained with the longer light-irradiation time on the bonding agent.
5) The optimum light-irradiation time on Photo Bond was 10 seconds.

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A joint dental epidemiological survey between Japan and China was carried out in Beijing, Leshan and Hong Kong in 1990, and data on the daily feeding habits and environmental factors of 1051 Chinese children 3,6,12 and 15 years old were obtained from their parents by means of a questionnaire.
The results were as follows.
1) Most of the infants (3 and 6 years old) in Leshan and Beijing were nurtured 640in a group, so the infants, especially in Beijing, had their meals out of their homes at the rate of over 80%.
2) The percentages of the infants who answered that they chew their food well were over 70% in each region, but many children chewed their food under 5 times before they swallowed it in Leshan.
3) The percentage of the infants who answered that they did not brush their teeth was approximately 60% in the 3 year old group and 40 to 50% in the 6 year old group in each region.
4) The frequency of snack intake was mostly 0 or 1 per day in Beijing and Leshan and mostly 1 or 2 per day in Hong Kong. Irregular snack intake was found exclusively in Leshan.
5) Snacks taken in Leshan and Beijing were almost sweetened foodstaffs.
6) Coca cola and juice were frequently taken even by infants in Beijing, and it seemed that this habit was a new tendency with respect to bevarage intake in large cities in China.

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A joint dental epidemiological survey between Japan and China was carried out in Beijing, Leshan and Hong Kong in 1990, and general and oral findings of 1281 Chinese children aged 3,6,12 and 15 years old were obtained.
The results were as follows.
1. The boys and girls in Leshan showed mostly the lowest values in body height and weight on the average among these subjects.
2. The prevalence of the temporomandibular joints (TMJ) dysfunction syndrome in boys and girls showed a high rate in Beijing, its rate being 50.0% in the 12656year old group and 20.0% in the 15 year old group.
3. The findings concerning oral hygiene were comparatively favorable in all the groups, but gingivitis was found even in the lower age group, the rate of the gingivitis being about 10 to 30% in the 3 year old groups. Dental calculus was mostly found at the lower central incisors in the 12 and 15 year old groups in all the regions.
4. The prevalence of mottled teeth was very high, especially in Hong Kong, and the rate there being 10.1 % in the 3 year old group,37.3% in the 6 year old group,27.2% in the 12 year old group and 43.2% in the 15 year old group.

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To clarify the developmental aspect of the electrical activities in the muscles participating in mastication and swallowing, a male infant was electromyographically studied from birth through the age of 36 months. The designated muscles were the anterior temporal, the masseter and the suprahyoid group. The action potentials of these muscles were recorded using surface electrodes during the eliciting of the bite reflex and during suckling (bottle feeding) and chewing (eating solid foods).
The main findings were as follows.
1) While the bite reflex was being elicited, (this is a continuous viselike closure for a few seconds of the mandible), rhythmical bursts of electrical activities were observed in the jaw-closing muscles (masseter and anterior temporal), but there were no such observable activities at all in the jaw-opening muscles (suprahyoid group).
2) Until around 4 months of age, the time lengths (msec) of the cycle, duration and interval of the EMG activities in the muscles during bite reflex and suckling were rather great and unstable. However, after 5 months of age, these values became shorter, steadier and more rhythmical.
3) As for the masticatory rhythm, the time lengths of the cycle, duration and interval of the EMG activities in the temporal muscle were close to stable from the beginning of chewing action at the age of 8 months through 36 months of age when the deciduous dentition was complete.
4) The time length (621±89 msec) of the cycle of the EMG activities in the temporal muscle during chewing showed a statistically significant difference from that (463±38 msec) in suckling, but indicated no such difference from that (622±44 msec) in bite reflex, suggesting some connection of the rhythms between chewing and bite reflex.

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Male Wistar rats, three weeks old which corresponds to the human ablactation stage, were used and the effects of a high-protein diet on bone formation in the mandibular condyle at the growth stage was investigated using an electron microscope.
The results were as follows:
1. Compared with the control group, the osteoblasts of the test group showed flat cells in the resting stage sporadically and the intracellular canaliculi were poor in development while the osteoid layer was interposed between the osteoblasts and the calcified layer.
2. Bone cells and osteoclasts showed no changes, as compared with the control group.
On the basis of the foregoing findings, it can be said that activation of the osteoblasts was decreased with the intake of a high-protein diet.

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To compare the effects of Tannin-fluoride preparation (HY agent) on the inorganic phases of the teeth, with those of ZnF2 and SrF2 which are components of the HY agent, we immersed synthetic hydroxyapatite (HAp) to the saturated solution of each fluoride and the HY agent for 1 day and 10 days, and studied the fluoride uptake of the HAp, changes in the acid resistance of the HAp and X-ray diffraction patterns of the HAp. In addition, we also compared them with the NaF solution which has the same fluorine concentration as the HY agent solution. The HAp immersed in the ZnF2 solution had the largest fluoride uptake, and superior to the others with respect to the acid resistance. It was thought that zinc phosphate and calcium fluoride which were recognized by X-ray diffraction analysis were effective on the acid resistance. Fluorine concentration of the SrF2saturated solution was about 1/100 of the other solutions, though the fluoride uptake of the HAp immersed in the SrF2 solution was 1/3 to 1/6 of the other samples. The acid resistance of the SrF2 sample was about 1/2 of the ZnF2 sample, but it was not different significantly from the HAp immersed in the NaF solution. The fluoride uptake of the HAp immersed in the HY agent solution was a little less than that of the ZnF2 sample. The acid resistance of the HAp immersed in the HY agent solution for 10 days was not different significantly from both the HAp immersed in the SrF2 solution and the NaF solution. Consequently, though the HY agent contains the tannic acid which converts collagen to collagenase-resistance forms, it was clear that the ZnF2 contained in the HY agent had great importance with respect to the increase of acid resistance.

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There are several reports on the extraction of lower deciduous canines for treatment of crowded lower incisors. In these cases, many clinicians recognized a change in dental arch form resulting from lingual tipping of the lower incisors and a lack of space for the erupting lower premolars.
The present study attempted to evaluate the influence on dental arch form caused by the early extraction of the canines.
The subjects were 28 children, who showed a lack of space for the erupting lower incisors at dental stages TIC or IIIA, and were divided into three groups as follows:
1. The group maintains space by utilizing lingual arch after extraction of lower deciduous canines.
2. The group not utilizing a space maintainer after extraction of lower deciduous canines.
3. The disking group on the approximal surface of the lower canines. Dental plaster models and lateral roentgenographic cephalograms of each child were taken just prior to and 12 months after extraction, with shedding or disking on approximal surface of the lower deciduous canines. The results were shown as follows:
1) Lingual tipping arose in the lower incisors and first deciduous molars in the group not utilizing a space maintainer.
2) Available arch length decreased in both groups with extracted lower deciduous canines.
3) Buccal movement of deciduous molars was observed just in the disking group.
4) Buccal movement of the first molars was observed in all groups.

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The purpose of this study was establishment of a "Young Children's Behavioral and Emotional Estimate Test in the Dental Setting" to help the dentist to choose appropriate management for 3 to 5 year old children.
At the dental clinic of the Department of Pediatric Dentistry, The University of Tokushima School of Dentistry, the following two studies were carried out.
In Study I, it was found in 100 three-to-five-year old children (49 male,51 female)and their mothers that the relationship between 90 items consists of the children's behaviour before treatment, the children's concepts nursing circumstances, incidence of chronic dental diseases, type of caries incidence at the first visit, dental office visiting experience before coming to the University Hospital, visiting experience at the University Hospital, and the personality of the mother, and the behavioral and emotional reactions during dental treatment.
As high correlative items,36 of the 91 items were extracted by analysis with Akaike's Information Criterion and Hayashi's Quantification Scaling Type II Method.
In study II,36 items were evaluated in 67 three-to-five-year old children (35male,32 female) and their mothers at their first dental visit.
The results are summarized as follows:
1. The 36 items were extracted as the "Young Children's Behavioral and Emotional Estimate Test in the Dental Setting" consist of 18 items of children's behaviour before treatment,16 items of the child's concepts of the dental clinic, operations and illness, dental office visiting experience before coming to the University Hospital, and personality of the mother.
2. For estimating the child's behavioral and emotional reactions during dental treatment, it is very important to observe in detail the child's behaviour and psychology from the time he or she enters the clinic, sits on the chair, until the time the dental treatment is completed.
3. The child's own words during the first dental visit about their motive for visiting the dentist and their feelings about dental treatment and the dentist were very valuable in estimating the child's behavioral and emotional reactions during dental treatment.
4. Dental office visiting experience before coming to the University Hospital, whether the child was capable or not of receiving dental treatment, if he or she had prior experience, and the personality of the mother were very valuable in estimating the child's behavioral and emotional reactions during dental treatment.
5. The success rate of the 36 items was 90.0% in 100 children (Study I) and 85.1% in 67 children (Study II), respectively. These results suggest that the "Young Children's Behavioral and Emotional Estimate Test in the Dental Setting" is clinically very valuable.

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It seems to be very important to establish the concept of nutritional assessment for the severely handicapped. The purpose of this study was to measure the values of the rapid turnover proteins (RTP) [prealbumin (PA), retinol binding protein (RBP) and transfelin (TF)] and the complements (CH50) for 52 severely handicapped who were institutionalized in an asylum.
The following results were obtained:
1. The mean values of RBP and CH50 at the first and second measurements for the subjects were lower (p<0.05 and p<0.001, respectively) than those of the control.
2. The mean values of PA and RBP for the subjects who were very retarded in the physical movement were lower (p<0.02 and p<0.05, respectively) than those of the other subjects.
3. These results suggest that RTP is very sensitive to the restriction of either protein or energy and can be used to detect subclinical malnutrition and monitor the effectiveness of dietary treatment for the handicapped.

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Application of the computer and the video digitizer to colorimetry of the teeth of children was investigated. As this equipment however was developed for computergraphics, the chromatical values are not assured. In the present experiment, the characteristics of the equipment were studied and the way to set the equipment was examined.
1. Measured values stabilized over 30 minutes after turning the power on for the equipment.
2. With HPV2 command, the signal for the theoretical value of 10YR7/3 was measured well when the color level was 3 and the level of γ conversion was 4. This corresponded to the HV-HP-S 013012 command.
3. Favorable results were obtained when the video camera was set as follows.
(3) Shutter speed: 1/60
(2) Iris: F3.4 and more or auto-calibration
(3) Gain: +6dB
(4) White balance: The camera was faced to the side wall first. Then, the white lens cap was attached and the focus was blurred maximally. The one-push white balance botton was pressed.
4. The chromatical values of the achromatic colors with the digitizer were nonlinear in characteristic and did not agree with the theoretical values.
5. Using K×M1/3+A (K and A are constants) for the basic mathematical transformation formula for approximating the measured values to the theoretical values produced favorable transformed values.

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Graft LCII was used for restoration of the proximal cavities of 30 deciduous anterior teeth and of 25 immature permanent anterior teeth having C/ and the course was observed clinically.
The results were as follows:
1. Poor marginal adaptation after one year was found in 2 cases (3.3%) of the deciduous anterior teeth and in 5 cases (10.0%) of the immature permanent anterior teeth.
2. After one year, no morphological changes were found in 28 cases (93.3%) of the diciduous teeth and in 22 cases (88.0%) of the immature permanent teeth.
3. Scarcely any Staining/discoloration of the restorative dental materials was found. Staining/discoloration was found in 2 cases each of the deciduous teeth and the immature permanent teeth.
4. Absolutely no marginal discoloration was found in 27 cases (90.0%) of the deciduous teeth and in 24 cases (96.0%) of the immature permanent teeth.
5. Secondary caries was found 3 months after restoration in 1 cases each of the deciduous teeth and the immature permanent teeth, and in an additional case of the immature permanent teeth in the first year.
6. No pulp reaction at the time of restoration was found in nearly all cases. One case (3.3%) of the deciduous teeth required pulpal procedure.
7. No abnormaly at all in pulp reaction at recall after one year was found in 26cases (86.7%) of the deciduous teeth and in 23 cases (92.0%) of the immature permanent teeth.
8. On the basis of the foregoing findings, Graft LCII has been suggested to be effective for restoration of deciduous teeth and immature permanent teeth in everyday clinical work of pedodontics.

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To observe the way child patients look at the dentist in the clinic, experiments were carried out with a photograph of the face of the dentist, who was looking straight at the subjects. The eye movements of the subjects were measured with the aid of a Visicon eye camera. An analysis then followed of the measurements. The children's visual reactions could be classified into the following four types: Their eyes (a) move from the center of the face to the outside; (b) are riveted on the face; (c) move from the outside to the face; and (d) are kept hovering around. the peripheral zone of the face. With the whole area of the face of the dentist including the contour given as the “figure” and the background as the “ground”, multivariate analysis (quantification theory 2nd family) and factor analysis were made of the relationship)between the “figure” and the “ground” of the child subjects to see if there were some relationship between the children's gaze and those factors associated with their mothers and home environment, and the results of the Takagi-Sakamoto juvenile personality test and other tests.
The following is a summary of our findings:
1. Of the total number of subjects.97% showed that their eyes moved within the confines of the “figure” before resting at the primary point of observation, meaning that they looked at the face in its entirety on the instant.
2. The remaining 3% showed that their eyes remained on the “ground”.
3. The psychological and personality factors of the subjects had certain effects on their manner of looking, albeit this was small.
4. Environmental factors and mother-child relationships had some bearing on the eye movements.
5. On the correlation axis where the correlation ratio is the largest, Group (d)was located, next coming Group (b), followed by Group (a) and (c).
6. It was also found that Types A and D in the Yatabe-Guilford personality inventory and the socially and personally stable characteristics in the Takagi-Sakamoto test are correlated with other factors.

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The purpose of the present epidemiological study was to survey the incidence of the temporomandibular joint (TMJ) dysfunction in children (3 yrs to 15 yrs old age). A total of 1893 children (941 girls and 952 boys) from one kindergarden, three primary schools and one junior high school located in Gifu, were examined in the sutdy. The subjects were divided into four age groups according to class in school such as pre-school (PS,3 to 6 yrs), junior class group of primary school (JPS,6 to 9 yrs), senior class group of primary school (SPS,9 to 12 yrs) and junior high school (JHS,12 to 15 yrs).
The results obtained were as follows:
1. The numbers and incidence of the children with TMJ dysfunction were 275(14.5%) out of 1893. In each group, PS, JPS, SPS and JHS were 13 (8.2%),57 (9.4%),115 (20.2%) and 90 (16.9%) respectively. There were no differences based on sex in each group.
2. Since considerable differences among groups, such as PS and SPS, JPS and SPS, JPS and JHS groups were noticed, the incidence of the TMJ dysfunction is likely increase with the age.
3. Among the three major symptoms found in the TMJ dysfunction, TMJ sound was the most frequent of 11.8% (223 of 1893), followed by TMJ and/or masticatory muscles pain of 3.4% (65). Children with these two symptoms combined were 1.1 % (13), whereas there were no children who complained of mouth opening difficulties in all groups.
4. The incidences of TMJ sounds in the PS, JPS, SPS and JHS groups were 8.2%,7.6%,13.0% and 16.0%, respectively. Significant differences TMJ sounds were noticed among groups, with differences based on sex no found in any group.

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To develop a pit and fissure sealant for partially erupting permanent teeth, we produced several trial cements combining tetracalcium phosphate (4CP) and glassionomer cements. We investigated their physical properties. Fuji Ionomer Type III and 0,2,5 and 10 wt% 4CP were combined. It was found that up to 10 wt% 4CP caused no decrease in compressive strength. However, the results of the setting time, solubility and adhesion to the enamel showed that no more than 5 wt% 4CP was permissible for a pit and fissure sealant. The setting time, compressive strength, solubility and adhesion to the enamel after 24 hours of 5 wt%4CP were 4 minutes,112.3 MPa,0.36% and 2.3 MPa respectively. While the release of Ca and P from 5 wt% 4CP was 1.5 to 2.5 times more than from Fuji Ionomer Type III after 3 and 4 days, the release of F was 90 to 50% less for 28 days.

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The purpose of this study was to investigate the influence of dental treatment on the urinary catecholamine level. The subjects were 25 healthy children aged from 3 to 11 years. They were divided into two groups: One group was 15children who received caries preventive proceedures, and other group was 10children who received cavity preparation with infiltration anesthesia using Citanest-Octapressin (Without epinephrine). The urine samples analysed were collected before and after dental treatment. Dopamine, noradrenaline and adrenaline were isolated from the urine and quantitative analyses were performed.
The results are summarized as follows;
1. There were no significant differences between the two groups in the concentrations of dopamine, noradrenaline and adrenaline before treatment.
2. The concentrations of dopamine, noradrenaline and adrenaline in the group undergoing caries preventive proceedures showed no significant difference between before and after treatment.
3. The group undergoing cavity preparation showed higher concentrations of dopamine, noradrenaline and adrenaline after treatment than before treatment. Especially the adrenaline concentration showed a statistically significant difference between before and after treatment (p<0.05).
4. The conversion ratio of dopamine, noradrenaline and adrenaline in the group undergoing cavity preparation showed higher than that of caries preventive treatment group. Especially the adrenaline coversion ratio showed a statistically significant difference between the group undergoing caries preventive proceedures and the group undergoing cavity preparation (p<0.05).

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Rett syndrome patients are found only in girls and show symptoms such as autism, mental retardation and cerebral palsy. The disorder is also characterized by the stereotypic hand activities, and disability in walking and pronounciation. Little is known about the specific characteristics of the dental traits in Rett syndrome children owing to the lack of case reports. The findings of 14-year-old girl affected with the Rett syndrome, who had undergone the dental treatment under the general anesthesia at Kyushu University Dental Hospital, were as follows.
1. Lower body height and weight were found.
2. Osteoarthritis of the spine was observed.
3. Bone age was advanced by 1-2 years older than the chronological age.
4. The mesio-distal diameters of the tooth crowns were smaller than the mean values.
5. Lateral cephalometric analysis showed micrognathism.
6. Labial inclinations of the upper and lower anterior teeth were found with tongue thrusting.
7. The patient received the dental treatment under the general anesthesia, due to severe mental retardation and definitive uncooperation.

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Osteopetrosis is a rare disorder characterized by systemic diffuse skeletal sclerosis. The disease is divided into the malignant type and the benign type. The former appears in infants or children and the latter appears in adults. We present here the case of a boy under oral treatment who was diagnosed as having osteopetrosis at 3 years of age. Results: 1. The erupted teeth were_??_and impacted teeth were_??_and_??_2.. The impacted tooth germs showed arrested root development, but the crowns of the_??_tooth germs were calcified.3. Since the patient was 5 years 10 months old, maxillary and mandibular dentures have been fitted.

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