The purpose of this study was to investigate the influence of the structural differences of color measuring instruments, background colors and the thickness of composite resins on the chromatical values of composite resins.
Composite resin disks which were 10 mm in diameter and 1 mm and 2 mm in thickness were made using the 3M Co. light-cured composite resin Silux Plus (shades: U, Y, DY, L, G, UO, YO). The specimens were stored in 37°C artical saliva. Chromatical values of the specimens were measured first without a background color and then against a white plate 1 day,1 week,1 month,2 months,3months,6 months,9 months and 1 year after curing. Color measuring was performed with the Murakami Color Research Laboratory Fast Spectrophotometer CMS-500 and the Flexible Sensor FS-3 (CMS-5), CMS-500 and the Flexible Sensor FS-1 (CMS-2), and the Murakami Color Research Laboratory Color Difference Meter CD-270 and the Improved Light Guide CD-270 (CD-270 Improved). The diameters of the head which receives the light from the object were: FS-3 (5 mm), FS-1(2 mm), and Improved Light Guide CD-270 (2 mm). The CIE 1976 L*a*b* color difference formula was used for the color specification.
1) In the case of both the 1 mm and 2 mm thick composite resin disks measured with or without background color, compared to the 1 day ΔE*ab values, the one-year ΔE*ab values of most shades were over 1.2 in all cases measured with the CMS-5, CMS-2 and CD-270 Improved.
2) Since the measuring times for the same specimens were high in this study, there is a high possibility that the composite resin discolorations were caused by the radiated light from the color measuring instruments.
3) Compared to the CMS-5 and CMS-2, the precision of the CD-270 Improved was low. In the case of the CD-270 Improved, it was hard to obtain accurate color changes for the composite resins over specified pericds of time, especially in the chromatical measuring of the a* values.
4) In the case of the CMS-5 and CSM-2, accurate color changes of the composite resins over specified periods of time were obtained for both the 1 mm and 2mm thick composite resin disks measured with or without a background color. The CMS-5 and the CMS-2 proved to be a precise color measuring instrument for chromatical measuring of composite resins over the specified periods of time.

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This study was undertaken to clarify the effect of changes in the masticatory function of the mandible due to food hardness. Three-week-old male rats of the Wistar strain were divided into the formed food group, the kneaded food group I, kneaded food group II, and powdered food group. The effect of the food was investigated after a period of six weeks.
The results were as follows:
1. The average compressive strengths of the food were 94.32 kg/cm² for formed food,45.23 kg/cm² for kneaded food I,14.20 kg/cm² for kneaded food II, and 0 kg/cm² for powdered food.
2. Based on Photo-densitometric observation, it was neveared that bone density of the alveolar bone was the highest for the formed food group and decreased in the order of the kneaded food group I, kneaded food group II, and powdered food group.
3. As for mandibular length and ramus height, the formed food group, kneaded food group I, and kneaded food group II showed about the same values. The powdered food group showed lower values.
4. Based on x-ray microanalysis, it was found that in Ca ratio (Ca/[Ca] c) and P ratio (P/[P] c) obtained from the comparison with the controls of the quantitative analysis bypoint analysis of Ca and P in the alveolar bone, the formed food group and kneaded food group I showed about the same values, which were higher than those shown by the kneaded food group II and powdered food group.
5. Fracture strength of the mandible was the highest for the formed food group and decreased in the order of the kneaded food group I, kneaded food group II, and powdered food group.
On the basis of the foregoing findings, changes in the hardness of food were proved to affect the internal structures of the alveolar bone.

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The use of composite resins in dental therapy has increased in recent years. In composite resin restoration, biological problems have been associated with pulpal lesions. It has been demonstrated that the pulpal lesions are the results of pulpal irritation induced by residual monomers and/or marginal leakage.
The amounts of the residual monomers (bis-GMA and tri-EDMA) remaining in six kinds of composite resins were investigated using HPLC. The following results were obtained:
1. The rates of residual bis-GMA and tri-EDMA were in the range of 6.5 to 23.1and 0.4 to 20.0%.
2. The chemically-cured composite resins had more residual monomers than the light-cured composite resins.
3. Among the light-cured resins, the amounts of the residual monomers decreased as the irritation time became longer, they increasing from the top to the bottom of the cured resins.

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Dental examinations and caries activity tests were performed on 100 children ranging in age from 3 years to 17 years 6 months (average: 7 years 3 months). The caries activity tests used in this study were MSB broth (Mucount: Showa), Resazurin Disc test (RD test: Showa) and Cariostat (Cariostat ^TM: Sankin). Dental examinations were performed using a dental explorer. Proximal caries were diagnosed by radiographic films and separation of the teeth performed with a separator. Children were classified according to Hellman's Dental Age and the relationships between the scores of the caries activity tests and the caries prevalence were compared.
The following results were obtained.
1. The results of the caries activity tests differed among the dental ages. At Dental Age III A, the rates of the high scores were higher than at other dental ages for all caries activity tests.
2. In the cases in which proximal caries were not detected by a dental explorer but were detected by radiographic films or separation of the teeth, the results of the caries activity tests differed among the dental ages. At Dental Age III A and Dental Age III B, the rates of the high scores (++ and _??_) were higher than at Dental Age II A and Dental Age II C for MSBB, the 24 hour scores of Cariostat and the 48 hour scores of Cariostat.
3. For all of the subjects, the increase in caries prevalence was observed among with an increase in the scores in all caries activity tests.
4. For all of the subjects, the coefficients of the correlation between the caries activity test scores and caries prevalence were high in the Cariostat and RD tests, especially in the 48 hour scores of Cariostat, while those, however, were low in MSBB.
5. In comparison with the dental ages, the coefficients of correlation between the caries activity test scores and caries prevalence differed among the caries activity tests. At all dental ages, a high correlation were observed between the caries activity test scores and the caries prevalance.
6. In all caries activity tests, the coefficients of correlation between the caries activity test scores and the incipient caries index were high.

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The relationship between the anxiety of the mother and the adaptability to dental treatment of the child was evaluated in 24 three-to-six-year old children and their mothers.
The an xiety of the mother was estimated with the State-Trait Anxiety Inventory (STAI) on the day of the “Mother Class” and the day of the dental trea tment of the child. The adaptability to dental treatment was rated from 1 (extreamly uncooperative)to 5 (extremely cooperative).
The results were as follows:
1. In the Anxiety-State of the mother, the score on the day of the dental treatment after the several visits was lower than the score of the “Mother C lass”during the second visit. In the Anxiety-Trait of the mother, there was no statistical difference between the score on the “Mother Class” and the score on the dental treatment.
2. The adaptability to dental treatment of the child was most influenced by the Anxiety-State of the mother on the day of the dental treatment among the Anxiety-State of the “Mother Class”, the Anxiety-Trait of the “Mother Clas s”, the Anxiety-State of the dental treatment and the Anxiety-Trait of the dental treatment.
3. The three-year old children were more influenced by the Anxiety-State of the mothers than the five-to-six-year old children.

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It is said that deciduous teeth are less sensitive than permanent teeth. In order to clarify this reason morphologically, innervation was investigated in human deciduous teeth by means of immunohistochemistry for neurofilament protein (NFP), a representative of neuron-specific proteins.
Numerous nerve fibers immunoreacted with NFP antiserum were found to be densely distributed in human deciduous teeth. However, the nerves in deciduous teeth seemed relatively fewer in number than those in permanent teeth. Undeveloped subodontoblastic nerve plexus was also recognized in deciduous teeth. Some of the NFP-positive nerves extending from this nerve plexus terminated in the vicinity of the odontoblast layer; major population of nerve fibers further penetrated into the predentin and dentin beyond the pulpodentinal border.
The distribution pattern of predentinal and dentinal nerve fibers in deciduous teeth was almost identical to that in permanent teeth. In comparison with permanent teeth, the occurrence of complex predentinal nerves which ramified in a dendritic fashion to show three-dimensional extensions in the predentin was considerably lower. Moreover, the terminal formation between the nerve fibers and the odontoblastic processes, the mechanoreceptive complex termed by Gunji (1982), was recognized in the predentin of deciduous teeth, though the frequency of its occurrence was rare. The smaller number of nerve fibers in deciduous teeth, especially of complex predentinal nerves in the predentin, and the bad terminal formation might be involved in the lower sensitivity in human deciduous teeth. Furthermore, the characteristic that deciduous teeth might easily react to the stimuli to form irregular secondary dentin also seemed to be one of factors in this problem.

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The purpose of this study was to investigate the interrelation of the reference points and planes on the palate along with individual maxillofacial growth through cephalometric analysis.
200 lateral cephalometric radiographs obtained longitudinally from 50 Canadian Caucasian boys and girls were borrowed from the Burlington Growth Center at the University of Toronto.
These cephalometric radiographs were taken at the ages 6,9,12 and 16years whose occlusions were normal at each age.
7 landmarks such as S, N, ANS, PNS, Ora, M (the middle point of mesiodistal crown diameter in the 2nd primary molar or the permanent 1st molar), and P (the deepest point of the palatal vault) were employed for the analysis of the cephalometric radiographs.
The following are the results of the present investigation.
1) The mean values of S-N to ANS-PNS angles and S-N to Ora-PNS angles were relatively stable through the ages of 6 to 16 years.
2) The differences of the mean values of S-N to Ora-M angles with the primary dentition, mixed dentition and permanent dentition became greater as the age increased.
3) The mean value of Ora-M to Ora-P at 9 years of age was notably less than that one at 6 years of age, otherwise the mean values of Ora-M to Ora-P became greater as the subjects became older after 9 years of age.
4) The pubertal growth difference was found clearly in these reference points and planes on the palatal vault between boys and girls. From the results above, it is advisable to take lateral cephalometrics when considering the growth changes in the palatal vault using these reference points and planes.

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A longuitudinal clinical and radiographic follow-up study was made of ten traumatized immature permanent incisors with root fractures. The material included eight patients aged 7 to 12 at the time of the primary visit. At the initial examination, all teeth exhibited markedly increased mobility and were treated by fixation and relief of the traumatic occlusion. In one tooth showing a complicated crown fracture, an apical fragment was surgically removed in conjunction with the root canal filling of the coronal fragment.
The mean observation period was 5y1m, ranging from 2y2m to 9y1m. In eight teeth (80%), retained pulp vitality, repair in the fracture area, approximately normal root development, and root canal obliteration were observed. Root resorption occured in 2 teeth. In one tooth, because negative response to electric stimulation and test cavity, endodontic treatment confined to the coronal fragment was performed. These clinical changes were found mostly within one year.
It is concluded that when optimally treated and maintained, teeth with root fracture have a long-term favorable prognosis.

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The preventive program for the pregnant women, babies and preschool children in the Town of Ishii, Tokushima was developed and begun in June,1986. The crude birth rate of the Town of Ishii was 244 in 1987 and 210 in 1990. The effects of the program were evaluated using a data-based epidemiological system.
The goals of this preventive program for the individuals who are involved and participate from birth to five-year-old are as follows: 1. to become caries free,2. to be motivated to assume responsibility for their own oral health and 3. to motivate their mothers and to make them capable of assuming responsibility for their children's oral health.
In this study the family background, the annual changes in caries prevalence and the factors influencing the prevalence of caries were analyzed in 1085 children aged from 0 to 5 years old who were born during years from November 1984 to October 1988.
The results were as follows:
1) The rate of children who were the second child or more was 55.8 per cent. The average number of people living with a family was 5.1 and the rate of the families composed of seven or more was 18.0 per cent. The rate of families comprising three generations was 56.0 per cent and the rate of children whose grandparent (s) were living in the neighborhood was 26.1 per cent.
2) The age of caries initiation in children who were born during years from November 1985 to October 1987 was lower and the age of caries initiation in children who were born from November 1987 to October 1988 was greater than that in children who was born from November 1984 to October 1985.
3) The characteristic common factors influencing the prevalence of caries in 1year 6 month old,3 year old and 5 year old children were the degree of plaque accumulation, the value of the caries activity test, the occupation of father, the occupation of mother, the mother's concern with caries prevention and the number of people living with the family.

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The purpose of this study was to evaluate the effects of preventive program on the tooth-, individual- and community level.
The results were as follows:
1) The rate of caries prevalence was lower in the children who participated more times in the six month dental health checkup during the ages from one year six months to 3 years.
2) The dental health education of one year six month old children only had no effects on the decrease of the dmf index when the children were 3 years old.
3) The annual changes in daily habits in one year six month and 3 year old children were recognized.
4) Four factors, i.e., unfinished weaning, irregularity of eating habits of between meal snacks, snack intake more than three times a day and no daily tooth brushing by the mothers at the age of one year and six months influenced significantly on the caries prevalence at the age of three.
5) Among the children with a high caries risk, the rate of taking dental health advice three months after screening as having a high risk was low, about 25-50 per cent.

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The purpose of this study was to clarify the protrusive mandibular movements in children. The protrusive mandibular movement was measured at Hellman's dental stage II A (3 boys and 6 girls, with a mean age of 6 year 1 month), stage III-A (2 boys and 7 girls, with a mean age of 8 years 8 months) and adults (9 male, with mean age of 24 years 7 months), with the use of the Selspot system. This measuring system is able to analyze simultaneous movements of the required multiple points in three dimensions and was proved to be sufficient for use on young children be cause of the small burden imposed on them while taking measurements.
Reference points were the incisal point, left and right tips of the primary canines (or permanent canines) and left and right dist-buccal tips of primary second molars (or permanent first molars). For the sake of comparison, the protrusive movements were standardized by the distance from the intercuspal position. The distance was from 0.5 mm to 5.0 mm intersected by 0.5 mm. The directions of the mandibular movements were calculated for five reference points at each measuring distance. Also the correlation of each angle of mandibular movement to overbite and overjet was computed.
The results may be summarized as follows:
1. Hellman's II A and III A groups were statistically smaller than the adult group as for the angles in the sagittal projection.2. The adult group showed the largest, while the II A group showed the smallest degrees in the frontal projection.
3. The II A group showed a highly positive correlation with the overbite, the overjet in the sagittal projection and with overbite in the frontal projection.
4. The III A group showed a negative correlation with the overjet in the horizontal projection.
5. Such results indicated that the III A group intermediates between the II A stage and adults.

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The present study was designed to discuss the relationship between the pressure in maximum intercuspation and the force display of the T-Scan system, and to investigate the number and pressure of occlusal contacts on the display of the T-Scan system at the clenching level of 20%,30%,40% and 50% respectively to the maximum EMG in the masseter muscle. Five persons with permanent dentition, none of whom had any gnatho-facial dysfunctions, were subjected to the study.
The results obtained in the present study are summarized as follows;
1) A significant relationship was found between the pressure in maximum intercuspation and the force display of the T-Scan system.
2) More the clenching level raised on the sensor, more the number of occlusal contacts and the force display (number and pressure) of the T-Scan system increased. This outcome showed similar trends when a silicon impression was used to examine the occlusal contacts.
3) Of the subjects who had a high DMF tooth index, the number and pressure of the occlusal contacts did not increase even if the clenching level was elevated.
As far as the results of present study is concerned, the T-Scan system is considered to be appropriate for examining the number and pressure of occlusal contacts.

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On the practical scene of dental treatment, with the view cf finding a possible age-related difference in a child patient's viewing his dentist's face between his visavis position of sitting up straight on the treatment chair and his inverted dorsal position, two test images, i.e. upright and inverted photographs of the dentist's face, were prepared and evaluating the eye movements of the patient using the visicon eye camera analytical examination was carried out. The results obtained are as follows:
1. Upright phtographs showed many patients starting viewing the dentist's face from above his nose, while inverted photographs showed a variation in the patients'viewing. The scanning route found a clue to the information acquisition in the head and the lower face besides eyes for upright and inverted photographs, respectively.
2. Younger patients had a tendency to gaze at a single region of the dentist's face; they showed similar tendency for overall grasp of his face. Upon recognition of the whole of his face, they showed such viewing as tracing his face along its outside region, i. e. outline, though not in a smooth way.
3. Older patients tended to obtain facial information by scanning only the characteristic region of the interior of the dentist's face. It was suggested that at whatever region of his face they might put their point of sight, they were able to grasp the whole image of his face and recognize it in a moment.
4. Patients in general showed unilateral preponderance, while, however, tended to become lower as the age increased.
5. Upright images showed a constant directivity of viewing, while inverted images showed its dispersability. For the group>8 years, however, there was observed such a directivity of viewing as overlaps their inverted images on their upright ones while rotating the former in their brain.
6. The above results indicated that an age-related difference in a child patient's recognizing his dentist's face was noted between his vis-a-vis position of sitting up straight on his treatment chair and his inverted dorsal position in communication with his dentist.

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In order to investigate the relationships between ability of tooth brushing and learning of the basic life custom in children, a survey was made with questionnaires. The subjects were 1127 mothers of nursery and kindergarten pupils ranging from one to six years of age who live in Nagoya and the suburbs.
The data were analyzed with the second class of the quantifying theory. The result of this study were summarised as follows;
1. Among the basic life custom, put on or off the clothes and excretion were not independent of their parents around four years of age, but cleanliness and meal were tended to somewhat slowly.
2. In children of three years of age, the following four items were related to the ability of tooth brushing; ‘Wash their hair alone’ ‘Wash their face alone’ ‘Pull on their stockings alone’ and ‘Pick up things like beans with chopsticks’.
3. In children of four years of age, the following three items were related to the ability of tooth brushing; ‘Wash their face alone’ ‘Take a meal with spoon and ricebow in their both hands’ and ‘Tie and untie the strings’.
4. In children of five to six years of age, there was no relation between the ability of tooth brushing and learning of the basic life custom.

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The following conclusions were drawn as a result of observation over a period of years on the same infants from age three when deciduous dentition was complete, with the purpose of regarding supernumerary mediodens on the maxilla. A survey made on the development condition, root resorption, change in position of the supernumerary teeth, and the effect on deciduous dentition and permanent dentition.
1. Out of 152 three-year-old children, those with supernumerary teeth amounted to five males and two females making a total of seven children, which was a 4.6% occurrence rate.
2. Of the above seven cases, one child had a supernumerary tooth. As for the impaction condition, two out of eight teeth normal impaction while six teeth had inverted impaction.
3. In one case the root development of a supernumerary tooth was completed at three year of age, but with the rest of the children the root was incomplete. Out of the incomplete root cases of incomplete growth, except for the two cases where the tooth was extracted during observation, the roots in all other cases were observed to be completed between the age of six to seven.
4. Categorizing the supernumerary teeth based on the root growth condition of normal deciduous teeth and permanent teeth, a tooth which had a complete root in child three years old was considered to be a supernumerary deciduous tooth. However, a tooth which had an incomplete root at age six to seven was considered to an supernumerary permanent tooth.
5. There were six supernumerary teeth, the positions of which changed during the observation; two teeth changed their axial inclination, and four teeth moved towards the apical side or occlusal side.
6. As for the root resorption of supernumerary teeth, there was one case judged as a supernumerary deciduous tooth in which the root was completely resorpted. On the other hand, there were just a few cases judged as supernumerary permanent teeth in which the root was partly resorpted.
7. Interference of the supernumerary mediodens on the maxilla to deciduous teeth, permanent teeth, dentition or the alveolar part exists temporarily, but this was nominal with longitudinal observation.

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1. We examined a case of 5 years and 2 months old boy with a solitary deciduous maxillary central incisor which was hardly distinguishable from the right or left side, and who did not have an upper labial frenulum, and who had an abnormality of the palate.
2. One year and 3 months after the initial examination, the solitary deciduous maxillary central incisor, having been extracted, was taken for histological examination. There were no findings which revealed a fused tooth in this examination.
3. The permanent successor of the solitary deciduous maxillary central incisor was also a solitary tooth.
4. In this patient, all conspicious findings were as follows. The boy had a solitary deciduous maxillary central incisor and a solitary maxillary central incisor.
We did not have an upper labial frenulum, and his median palatine suture was swollen. The patient had an anamnesis due to a nasal ailment and the abnormality was localized in his median portion of the nose or oral cavity and face.

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This report concerns four cases of odontogenic tumors which caused delayed eruption of lower permanent first molars.
The findings were as follows:
1. Four cases of odontogenic tumors (three males and one female) aged 8 years 8 months to 13 years 2 months. All cases caused delayed eruption of lower permanent first molars.
2. In all four cases, intraoral findings revealed that there was no demonstrable abnormality in the gingiva.
3. Radiographically, each case showed the permanent first molar to be impacted and well-defined radiolucency in which there was radiopaque material.
4. The histopathological diagnoses were ameloblastic fibro-odontoma, complex odontoma, odontogenic fibroma and ameloblastic fibro-odontoma.
5. The treatment was simple excision of the tumors while the impacted permanent first molars were left in all cases. After the operation the three impacted teeth erupted, and the other showed a tendency toward eruption.

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Schwartz-Jampel syndrome is synonymous with chondrodystrophic myotonia, characterized by dwarfism, specific face with blepharophimosis, skeletal deformities and myotonia.
An eight-year seven month old girl who was diagnosed as having the Schwartz-Jampel syndrome visited the clinic of Pediatric Dentistry, Tokushima University Dental Hospital for a malocclusion.
The systemic findings were (1)short stature, (2)specific face with blepharophimosis and small mouth, (3)joint contractures of the hip, knee and elbow and limited joint movement, (4) walking difficulties, (5)normal intelligence and (6)as revealed in blood examinations, a slight low level of MCV and MCH, high level of CPK and LDH, and low level of IgA and IgG.
The oral findings were (1)malocculusion caused by the small upper and lower, especially upper, jaw and the normal size of the teeth, (2)no deficiency in the number of teeth, (3)a high arched palate, (4)no morphological abnormalities of the mandibular head and mandibular fossa and normal joint movement, (5)longer coronoid process than articular process and a somewhat large antegonial notch, (6)continuous muscle activity of the masseter and anterior part of the temporal muscles during rest and (7)unstable mastication rhythm.

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