For securing better permanent dentition, proper guidance and care of the occlusion of primary dentition in children is essential. A study model detection system was newly developed in our department, permitting observation of the arch form on a computer CRT. The purpose of the study was to investigate the method and accuracy of the system.
The main system consists of a CCD camera (PX-390A, PIAS), positioned and standardized at a right angle 350 mm apart from the measuring plane, an image analyzer (LA525MS, PIAS), a personal computer (PC-9801RX, NEC), digitizer (D3110, PIAS), and sampling images managed and displayed on a CRT.
In the first investigation, the strain of the camera lens was studied by measuring a standarized graph paper via the system. It was disclosed that the results obtained by the image analyzer tended to reflect smaller values at the edges of the CRT than in the center of the CRT (maximum measured error -2.97%, mean measurement error -0.45 %) than the real distance.
In the second investigation, the length and width of three upper study models were examined and the differences between measuring methods; i. e. image analyzer and slide calipers measurement were evaluated. As a result, the mean measurement error of the study model by using an image analyzer were -4.01 % compared to the measurements of the slide calipers. However, the values of the coefficient variation of the image analyzer measurements were very low compared to the slide caliper measurements.
In conclusion, since a study model detection system by using the image analyzer showed high dimensional accuracy, it could be useful to examine a study model for the diagnosis of occlusion.

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The purpose of this study was to clarify the characteristics of suckling and chewing movements in guinea pigs, to examine the time of transition from suckling to chewing, and to identify each movement.
Twenty baby guinea pigs were observed with respect to their suckling movements and chewing behavior, while the intraoral pressures were examined with a pressure transducer: Dome Kit (Nihon Koden Co. ) while the jaw movements were recorded with the Saphon Visi-Trainer (Tokyo Shizai Co. ), when a specially devised nipple was inserted into the mouth of the guinea pigs.
Throughout the suckling period, intraoral pressure gave only negative pressure, whereas alternative negative and positive pressures were recorded in the chewing period. As to the jaw movement, simple opening and closing movements were recorded in the suckling pericd. However, more lateral movements were recorded after birth.
From the results obtained, the baby guinea pigs showed suckling movements only until 9 days after birth, followed by mixed movement, and subsequently showed chewing movements after 26 days. Thus, it was possible to identify the transition from the suckling to the chewing pericd through the examining the intraoral pressure and jaw movements.

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Different types of ccclusion in normal as well as in malocclusion during the primary dentition stage were investigated. A total of 155 plaster models was made from children,84 males and 71 females all of whom in the Hellman's dental age IIA stage(aged 3 to 5 years). The results were as follows.
1. The incidence of various types of occlusion was normal occlusion 56.8%, deep over bit 29.0%, open bite 7.7%, edge-to-edge bite 4.6%, progenia 1.9%, normal being the most frequent.
2. In considering the terminal plane of various types of occlusion, M-M step type was the most frequent, followed by V-V and D-D step types. In terms of age, V-Vtype had a tendency to decrease with age increase.
3. The most common terminal plane incidences of the various occlusal types were as follows: in normal occlusion, a V-V type, in open bite, an M-M step type or D-D step type, in edge-to-edge bite, an M-M step type, in deep over bite, a D-D step type and in progenia, an M-M step type.
4. In normal occlusion, V-V types tended to decrease with age. An increase of M-M step types among the 5-year olds in comparison to the 3-year olds was seen. For deep over bite cases, there was a tendency for D-D step types to increase with age.
5. In the maxilla, the total interdental spaces in all types of occlusion decreased among the 5 year olds more than among the 3 year olds. In the mandible total interdental spaces (in different types of occlusion) increased more among the 5 year olds rather than among the 3 year olds.
6. In the normal occlusion as well as in the deep over bite groups the M-M step type had the highest amount of total interdental spaces in the maxilla, the spaces being greater among the deep over bite groups (the latter). Total interdental spaces in the mandible among the two groups demonstrated no significant difference.

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The objective of this study was to investigate F release from an intraoral fluoride releasing device (IFRD), enamel uptake of F from IFRD and the acid solubility of enamel treated by IFRD. The IFRD used in this study was a membranecontrolled, reservoir-type device and was made at Southern Research Technologies in Birmingham, Ala. Enamel slabs were prepared from human permanent premolars extracted for orthodontic reasons.
The following results were obtained.
1) There was a gradual increase during the first 5 days. However, after the first 5 days the rate of F release was negligible over the test period. Over a test period of 90 days, the average rate of F release was 52.2μg/day.
2) The uptake was higher in the enamel immersed with the IFRD for 30 days compared to the control. The F concentrations in the 2nd and 3rd enamel layers increased markedly.
3) The least amount of dissolved Ca was found when IFRD was used both before and during exposure to acid (reduction rate: 64.1%). A greater amount of dissolved Ca was observed when the IFRD was used only before exposure to acid (reduction rate: 55.4%). The greatest amount of dissolved Ca occurred. when the IFRD was used only during exposure to acid and not before (reduction rate: 18.2%).

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Dental hygiene and therapeutics of 61 children with congenital heart disease (CHD) seen at the dental clinic of Chiba Children's Hospital were discussed.
Their ages ranged from 1 to 17 years, the average being 7.5 years. The incidence of carious deciduous teeth of CHD children was higher than that of normal Japanese children reported by The Health Policy Bureau of the Ministry of Health and Welfare, Japan (1987).
There were no essential differences in caries incidence between the cyanotic (37 cases) and the acyanotic group (24 cases). Furthermore, severe cyanotic children did not always have a large number of carious teeth.
According to the questionnaires filled out, parents of CHD children had comparatively poor recognition of the oral hygiene of their children. These results lead to the conclusion that strong dental care and parents concern are more necessary for CHD than for normal children.

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The purpose of this study was to investigate the gingival color changes of the previous child stage that appear in periodontal diseases. Maxillary anterior gingiva of 109 children with clinical normal gingiva who were from 3 to 14 years old and 21 young adults, who were from 18 to 28 years old were chromatically measuredusing the light guided color difference meter CD-270 (Murakami color research laboratory).
The results were as follows.
1) Joining the image fiber with the color difference meter improved reappearance and clinically color measurement was easily possible.
2) The measurement data of the stage classification showed fall peak on data L* and showed in increase on data a* in the mixed dentition stage. However, that was no much change on the data b* at all stages.
3) The measurement data of the stage classification showed lower value at the attached gingiva compared with the papilla and marginal gingiva on data L*. In the opposite direction, it showed a higher value at the attached gingiva on data a*. The difference between the marginal gingiva and the attached gingiva was scarcely show on data b*.
4) As for disparity according to sex, in the primary dentition stage data a* showed a higher value with women compared to men. The color difference did not show in the mixed dentition stage. Also data L* showed a higher value with men in the parmanent dentition stage.

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To develop a pit and fissure sealant for partially erupting permanent teeth, we modified the liquid of tetracalcium phosphate (4CP) cements. We investigated their adhesion to enamel as well as their properties, and found the most promising compositions of the liquid. We also investigated the changes in each cement mixture when immersed in distilled water or phosphate buffered saline. The liquid consisted of 50wt% water,30wt % polyacrylic acid (mixture of various ratios of 2 kinds which differed in number-average molecular weight),15wt%citric acid, and 5wt% tartaric acid. By changing the ratio of the 2 kinds of polyacrylic acid, we obtained 5 kinds of liquid. They were mixed with 4CP and their setting times, compressive strengths (according to the ADA specification NO.61for polycarboxylate cements), and adhesion to enamel were measured. Using 25wt% polyacrylic acid whose number-average molecular weight was 5000 and 5wt% polyacrylic acid whose number-average molecular weight was 12000, we obtained a mixture which had the widest utility, high adhesion, and high compressive strength. We then made 4 kinds of powder consisting of 4CP and/or CaF2-((1)4CP, (2)99wt% 4CP-1wt% CaF2, (3)90wt% 4CP-10wt% CaF2, and (4)70wt% 4CP-30wt% CaF2) and 2 kinds of powders consisting of 4CP and SrF2((1)98wt% 4CP-2wt% SrF2, (2)90wt% 4CP-10wt% SrF2). We mixed them with the liquid stated above and each mixture was examined on the same properties. It was found that only 90wt% 4CP-10wt% SrF2 decreased its compressive strength. We also immersed these mixtures in distilled water or phosphate buffered saline, and examined how their 4CP converted to hydroxyapatite (HAp) by X-ray diffraction.4CP converted more quickly to HAp in phosphate buffered saline than in distilled water. The presence of CaF2 or SrF2 stimulated the conversion to HAp.

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The Authers considered that occlusal guidance is needed for the total management until the completed permanent dentition irrespective of the pedodontics and the orthodontics. We put into practice the occlusal guidance in common with concepts, technology and fee system at the orthodontic department in the dental hospital of Kagoshima University.
The results were as follows:
1. By classification of malocclusion, the percentage of each kind was as follows: corss bite (53.8%), crowding (25.5%) and maxillary protrusion (7.9%).
2. Based on the distribution of the pathogenic factors of the malocclusion, the most numerous factor was skeletal, next was functional and followed by discrepancy factors.
3. It is considered that the clinical occlusal guidance was in need of including the regional characteristics and social enviroment.
4. It seems to be a pedodontic characteristics that just 103 patients (31.3%). At the time of the first visit to our clinic had other chief complains than malocclusion.

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The purpose of this study was to evaluate clinically low viscosity composite resin used as class II restorations in primary molars. The subjects of the present study were 61 children aged 2 to 10 years who visited the Pedodontic Clinic of Tohoku University Dental Hospital. A total of 153 class II cavities were treated with Clearfil SC-II (Kuraray). The observation period varied from 6 to 74months after the treatment. The restorations were examined with regard to spacing or stepped abrasion in the marginal region of the fillings, fracture, loss, attrition and discoloration and recurrent caries and/or pulpal involvement of the treated teeth.
The following findings were obtained:
1) 101 cases (66.0%) were evaluated as clinically acceptable. About 80% of those treated primary molars exfoliated and were replaced by permanent teeth.
2) 52 cases (34.0%) exhibited poor restorative conditions. Of those cases,31(20.3%) were treated again,4 (2.6%) are being observed periodically as follow up cases, and in 17 cases (11.1 %) the primary molar exfoliated phisiologically or was extracted when the succeeding permanent tooth appeared.
3) The incidences of poor restorative conditions among children who were treated at the ages of three and four years were higher than among children treated at the ages of greater than six years.
4) There was a tendency for poor restorative conditions to occur comparatively soon after treatment.
5) Among the poor restorative conditions, recurrent caries and stepped abrasion in the marginal region of the restorations occurred more frequently.
6) Those conditions were observed most in cases involving upper first primary molar restorations.

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The purpose of this study was to evaluate the effects of different foods on the flow rate of saliva in five-year-old children.
The foods selected were cookies, pickled radish, sausage, mash potatos, apples, and steamed rice. The volume of saliva secreted by 10 subjects of each gender was determined by subtracting the initial weight of the food from that of the food bolus after the subjects had chewed it normally and then spat it out into a weighed container, instead of swallowing.
Mean chewing times per 10 g of food were highest with cookies (124.2±100sec. ) and lowest with rice (32.6±19.9sec. ), and these were inversely related to the initial water content of the foods (r= -0.85, p<0.05). There were no differences in salivary flow rates due to gender and the mean flow rates of six different foods was 3.6±2.7ml/min (highest with cookies and lowest with rice). The mean percentage of the foods wihch were either inadvertently swallowed or remained stuck to the teeth or oral mucosa were calculated to be 13.7±6.4, and the salivary flow rates which were obtained in this study seemed to be a slight estimation of the actual flow rates.

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The object of this study was to determine the relative contributions from gustatory and mechanical stimulation of the salivary flow in response to consumption of four foods in five-year-old children. In a preliminary study on 14 boys and 16girls the weights of normal bite-size portions and their chewing times for cookies, pickled radish, apples, and boiled rice were established for each subject. In the main study the foods were either (a) divided into the calculated bite-size normal portions or (b) the portions were mashed (untreated rice). The subjects chewed the foods of type (a) in the normal way but, with type (b), simply held the food between the plate and the dorsum of the tongue, with no masticatory movements (tasting). After the normal chewing time the food was not swallowed but spat into a weighed container; the volum of saliva secreted was determined from the increase in weight of the food portions.
Cookies elicited a significantly higher flow rate than did the apples, pickled radish, and rice; the flow rates in response to tasting, as a percentage of those in response to chewing were 95.1±31.6,97.0±35.3,87.9±40.6 and 71.2±17.8, respectively. It was concluded that the effect of the gustatory stimulation of foods is much more important than the mechanical stimulation from chewing in producing the flow of saliva.

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In order to observe the sagittal relationship between the upper and lower dentition and/or occlusal contacts on an occlusal plane, a computerized image detection system ‘Occlusogram’ was newly developed in our department. In the present study the ‘Occlusogram’ was introduced and sagittal occlusal changes from the primary to permanent dentition were evaluated.
The subjects examined in the study were 14 children with primary dentition,14 children with early mixed dentition,14 children with late mixed dentition and 15 adults with permanent dentition, who all had healthy and normal occlusion. Cast models of the dentitions and bite checks obtained by black silicon paste in the intercuspal position were used in the study. Each outline of the upper and lower teeth, and occlusal contacts input by a CCD camera to a computer were superimposed on the occlusal plane according to the standard line. To assist analysis five standard points, an incisor point, bilateral canine points and bilateral molar points were defined. Fifteen measuring items were then evaluated and the following results were obtained.
1) A significant increase in the arch width of both jaws was found, whereas the arch length of the lower jaw decreased with dentitional growth.
2) The length from the incisor to the molar point of both jaws increased significantly with dentional growth.
3) As the dentition developed the lower molar point migrated mesially compared to the upper molar point.
4) As compared to the upper incisor point the canine point of both jaws moved disto-buccally, and the molar point of both jaws moved mesio-buccally relatively.
As observation of the dentitional relationship between both jaws in the same plane became possible, ‘occlusogram’ was considered to te useful for examination in occlusal guidance.

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Two cases of children (11 and 12 yrs. old) with craniomandibular disorder (CMD), who complained of TMJ sounds and mouth opening limitation, were reported. Since the possible causes of the cases were considered to be the occlusal premature contacts and lower jaw shift due to the prolonged retention of the lower 2nd primary molar, the retended tooth was extracted. After the extraction of the tooth, significant dentitional and occlusal relations adjusted and all symptoms and signs disappeared within a few months.
The following summerized dentional and occlusal changes were noticed after the treatment of CMD:
1) The midline shift of the lower jaw was corrected.
2) The bilateral asymmetry of the dentition of the lower jaw was corrected.
3) The bilateral asymmetry of the molar occlusion was also adjusted.
4) After treatment, the dentition of the lower jaw shifted to a more balenced position against the upper jaw.
It was revealed from these cases that the prolonged retention of the primary molars leads to the physiological occlusal change of the permanent dentition, and subsequently causes craniomandibular disorders.

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Two cases of dentin dysplasia type II are reported. These are very rare cases with a rate of incidence under 1/10000 or 1/100000.
The results of the clinical oral findings are as follows.
1) The patients were 10-year 6-month and 9-year 11-month old boys.
2) The general examination of Case I showed delayed growth for two years. Case 2 showed good general growth.
3) Roentgenographic examinations showed an unusual form of the pulp chamber in all of the teeth. In the external form of the pulp chamber, the stricture of the root canal at the cervical area, and a thistle tube-shaped pulp chamber were observed.
Radiopaque findings with many miliary round forms in the pulp chamber were found. The Coronal pulp chamber of the molar teeth was compressed in the vertical axis of the tooth with stricture of the root canal.
From the above findings, the two cases were diagnosed as dentine dysplasia type II using Shield's classification.

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Kabuki make-up syndrome (KMS) is a multiple congenital anomalies syndrome, first described in 1981 by Niikawa et al., and Kuroki et al. KMS is characterized by five main manifestiations consisting of a peculiar face, short stature, mild to moderate mental retardation, unusual dermatoglyphic patterns and skeletal anomalies. The peculiar facies characterized by long palpebral fissures with eversion of the lateral third of the lower eylid features reminiscent of the makeup of the actors of Kabuki, Japanese traditional play. KMS is considered as an autosomal dominant disorder or a pseudoautosomal dominant disorder, and a fresh mutant. The etiology of KMS is unknown and the sex ratio is even.
I undertook the dental treatment of a KMS female patient. The patient (5years 3 months of age) visited the pediatric dental clinic, Nagasaki University Dental Hospital. The chief complaints were masticatory, pronouncing and esthetic disorders caused by hypodontia and abnormal dentition.
Mild mental retardation and mild short stature were observed. Craniofacial anomalies consisting of long palpebral fissures, lower palpebral eversion, left upper palpebral closure hypofunction, mild blepharospasm, epicanthus, internal strabismus, depressed nasal tip, short nasal septum, big nostrils, arched eyebrows, large prominent ears, preauricular dimple and low posterior hair line were observed. Skeletal anomalies consisting of short fingers, short middle phalanx of the fifth fingers, clinodactyly of the fifth fingers, short toes, spina bifida occulta were observed. Dermatoglyphic findings were finger pads, increase of ulnar loop patterns, presence of interdigital triradius bc and cd. Early breast development was also observed.
The dental anomalies were partial anodontia of the primary and permanent teeth, enamel hypoplasia of all primary teeth and superior labial frenum anomaly. The widths of the primary teeth crowns and the dental arches were smaller than those of the average values of Japanese children. High-arched palate, anterior and posterior cross-bite and anterior open bite were observed. Occlusal surfaces or occlusal and buccal surfaces of the primary molars were decayed due to dental caries, and the def ratio was 27.8.

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Previous reports concerning impacted teeth and supernumerary teeth have been reported but the majority of those reports were focused on the occurrence rate and position, tooth shape and other factors. A few investigators reported on the extraction time and the marsupialization time.
On this occasion, we experienced a case having mesiodens and an inverse impacted central incisor in the maxilla. We investigated this case from the point of view of extraction time and marsupiali-zation time.
1) After the observation period of 2 years,8 motnhs from the first visit, we extracted the supernumerary tooth and made a marsupialization of the impacted. tooth at 8.11 years. We started the traction treatment after a 3-month observation period.
2) The root formation of the supernumerary tooth was recognized as almost normal and the tooth could be moved to the appropriate position during a period of 1 year 8 months from the marsupialization. We, therefore, proceeded to the retention treatment.
3) The patient had no complaints during the past 1 year and 4 months and now she is placed on follow-up.

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The application of an ultrasonic device for endodontic therapy is expected to exhibit not only the filing effects but also a cleansing effect in the root canal. However there has been little detailed research to evaluate the clinical effects regard in deciduous teeth. The purpose of this study was to evaluate the clinical effect on cleansing root canals of deciduous teeth by the use of an ultrasonic device.
The subjects of this study consisted of 27 children (15 boys and 12 girls), who had 33 deciduous molars having infected root canals with gingival abscesses.
The results obtained were as follows:
1. The number of treatments was up to 3 times from the beginning of the root canal treatment to the root canal filling.
2. The teeth with recurred gingival abscesses showed negative during the observation period within one year of up to one year.
3. It was observed in a few cases that there might be some possibility of destroying the root apex at the time of canal preparation or ultrasonic irrigation. However there was no abnormality in the root resorption radiographically over a long term.
4. The pathological bone resorption that localized at the area from the bifurcation or trifurcation to the root apex was repaired radiographically after the root canal filling.

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Traumatically injured teeth were examined clinically and radiographically in 242 children with 186 immature permanent teeth and 190 primary teeth. Their etiology and epidemiology were discussed. The prognoses were surveyed in 45 immature permanent teeth and 61 primary teeth of 70 children who had been injured over 3 years previously.
The results as follows were obtained:
1) The traumatic injuries of teeth occurred frequently at 1 year of age in the primary dentition, and 8 years of age in the mixed dentition. The upper central incisors were most frequently affected in both the primary and permanent dentitions. With high percentages, intrusion and subluxation were found in the primary teeth. On the other hand, fractures involving dentin or pulp occurred most frequently in the permanent teeth.
2) Developmental and mineralization defects were found in 33% of the permanent successors of the children who had injured their primary teeth. A significant relation was not found between the occurrence of mineralization defects on permanent successors of the patient and the age at the time of the trauma.
3) Unsuccessful healings after treatment of the traumatically injured immature permanent teeth were evident in 22% of the teeth.
4) Long-term observations of traumatically injured teeth are necessary to minimize unsuccessful healing.

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An unusual case of ameloblastic fibro-odontoma in a 3-year-old boy is reported.
The patient complained of a diffuse swelling in the gingiva of the maxillary right primary central incisor. The radiographic evaluation, which included an intraoral view and an occlusual view, revealed a well-circumscribed monolocualar radiolucent lesion without a radio-opaque mass.
According to the histological findings, the tumor mass was composed of primitive connective tissue resembling dental papilla. Proliferation of odontogenic epithelium and hard tissue resembling enamel, dentin and cementum were found. Consequently, we diagnosed ameloblastic fibro-odontoma.
As treatment, the tumor was removed simply and the primary central incisor was left.
The clinical course is excellent, and there is no evidence of reccurrence.

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