The immature permanent teeth, especially the first molars, show a high caries rate prior to the start of their functioning as teeth. While a sealant is generally applied as part of the system for the prevention of caries, the breaking and falling of of the filling materials are often experienced in clinical treatment. Most of the causes of the unsatisfactory situation in the prognosis are considered attributable to technical errors and to the cleaning of tooth-surfaces, pits and fissures. Therefore, the authors, using a tooth-surface polisher and a fissurecleaning chip, cleaned an extracted human tooth and observed the cleaning effects with SEM. The authors also applied etching to the tooth-surface and to the pits and fissures after cleaning, and observed, with SEM, etching effects that differ according to the cleaning effect. As a result, the following information was obtained:
1. When the tooth-surface was cleaned with a brush-cone, some enamel cuticles remained in the depressed portions but, when a tooth surface polisher was used, the dental cuticles were found to have been removed and the tip of the enamel rod exposed, suggesting the effectiveness of the polisher.
2. When the pits and fissures were cleaned with an explorer and a brush-cone, a large volume of deposits that appeared to be of organic nature was found. However, in the case of cleaning with a tooth-surface polisher, while the deposit that appeared to be soft was observed to have been removed, the deposit apparently in process of calcification had not been eliminated.
3. When the cleaning of pits and fissures was done with a fissure-cleaning chip, it was noted that the deposits had been removed within the reach of the chips and, moreover, some exposed portions of fresh enamel, resulting from the shaving of first-layer enamel, were observed.
4. As to the etching effect on the tooth-surface, it was observed to be greater in the case where there was no remnant of the enamel on the surface-layer to which the tooth-surface polisher had been applied. As was also confirmed from the observation of the surface of a sealant replica, the cleaning effect in the pits and fissures was found to be more certain when the fissurecleaning chip was used.

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This study was undertaken to obtain long term clinical evaluation of posterior composite resin restorations on young permanent molars.
47 decayed permanent molars of 6-13 year old children were treated with Clearfil Posterior (Kuraray) and examined at baseline, and 1,3,6,12,18, and 24 months after restorations.
At each examination, clinical assessments, color slide photos, and replications of the restored teeth were obtained, so that serial changes of the restorations were able to be observed using these replicas with SEM, etc. Findings were as follows.
1. Marginal fractures were observed in 10 cases (21.3%) during 24 months. Nine of them were simple fractures caused by excess resin overfilled beyond the margin. They seem to have encountered no difficulties by re-polishing the fracture ends. But in one case, the fracture extended inside the prepared cavity and gradually increased its extent.
2. Secondary caries were observed in 6 cases (12.8%) during 24 months. They resulted from the remaining infected dentin at the restoration in one case, and from the fractured edge of the resin in another case.4 other cases were due to insufficient extension of the preventive cavity preparation at the fissures.
3. Partial falling out of the resin body was found in one case. It seemed a gradual falling out was observed from the defectve part because of air bubbles mixed in by mistake at the restoration.
4. At 12-months, one case showed hypersensitivity to cold, and another case mastication pain, but they were very mild and showed no discomfort at 18-months.
5. In two cases, marginal coloring were observed, resulting from secondary caries in one case, and pigmentation of some stain at surface indentation.
6. In conclusion, Clearfil Posterior functioned well at the 24th-month evaluation. Also most of the clinical troubles seemed to have resulted from inadequate technique rather than material problems.

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For the purpose of investigating the thickness of the dental structure in the maxillary second deciduous molars, the distances between the pulp cavities and the external boundaries of the teeth were measured.
Materials: The materials used were 63 teeth without caries and with caries localized to the enamel.
These specimens were divided into 3 types according to the degree of the root resorption; type I for less than 50% resorption of the root, type II for more than 50% resorption of the root and type III for the crown only.
Methods: For visualization of the pulp cavity, india ink was infused into the cavity using a vacuum pump. After dehydration, a transparent specimen was prepared by dipping the tooth in styren-monomer and embedded in epoxy resin. Markers were notched on the surface of this embedded block parallel to the dental axis.
The block was then sliced mesiodistally into serial sections of 93μ using a microtome (used for cutting hard tissues).
The serial sections were enlarged ten-times and traced. The traces were three-dimentionally reconstructed using a personal computer. The distances from the various points of the crown were measured on the reconstructed stereogram. The cross-sections used for these measurements consisted of the occlusal aspect, the center of the mesio-distal diameter, the center of the bucco-lingual diameter, the centra fossa, mesial and distal pits and the pulp horns.
Results:
1) The smallest measurement for the distance from the pulp cavity to the occlusal surface was 2.5-2.6 mm at the mesio-buccal horn.
2) In the cross-section of the pulp horn, the smallest measurement for the distance from the pulp horns to the bucco-lingual and interproximal surfaces was 2.7 mm at the distance from the mesio-buccal horn to the mesial and buccal surfaces.
3) The smallest measurement of the distance from the maximum bulge of the pulp cavity to the bucco-lingual and the interproximal surfaces was 1.9-2.0mm. This tendency was observed at the mesial side in the bucco-lingual aspect and the central fossa.
4) The smallest measurement in the cervical regions was 1.4-1.7 mm at the mesial side of the buccal aspect.
5) According to the degree of the resorption, a few portions in which the 37thickness of the dental structure varied significantlly was observed. Therefore on the occation of the cavity preparation, it is dengerous that too much reliance is placed on the physiological formation of the secondary dentin.

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For the purpose of investigating morphological changes of the child gingival epithelium during resorption on the roots of deciduous teeth, a total of 52 clinically normal gingivae, obtained from subjects ranging in age from 3 to 7 years were examined. The subjects were devided into 4 groups depending on the stage of the root resorption. The sample gingivae were examined by the ultrathin section method. The following were the results of the present investigation.
1) The pedicles, present at the basal surface of the basal cells and extending toward the connective tissue, grew in size along with the root resorption. Because these changes were attended with an increase in the number of the hemi-desmosomes as well as the anchoring fibrils, the root resorption may have strengthened the cohesion between the basal cells and the connective tissue.
2) Many tonofilament bundles and melanosomes were observed in the cytoplasm of the basal cells in the later stages of the root resorption.
3) Less developed cytoplasmic projections were observed in the spinous cells of the child gingival epithelium, and the intercelluler space of the spinous layer was relatively narrower than those of adults. The intercelluler space, however, was enlarged in the later stages of the root resorption, and the intercelluler junctions were the least well defined in this stage.
4) Odland bodies of the granuler cells increased in number with the root resorption. Especially in the later stages of the root resorption, Odland bodies were observed in the cells of the lower cornified layer, and discharged the characteristic lamellated structures into the intercellular spaces of the lower cornified layer. It was suggested that the increase of the Odland bodies in the later stages of the root resorption correlated to the spread of the intercellular spaces of the basal and the lower spinous layer in this stage.
5) Dense homogeneous deposits were observed in the granular cells, but no morphological changes were seen with the root resorption.

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There are many reports on the caries prevention of young permanent molars by use of pit and fissure sealants, but few reports concerning the deciduos molars. To study the caries-preventive effects of pit and fissure sealants on the second deciduous molars,180 second molars from 66 children (mean age: 3y11m) were sealed with a pit and fissure sealant after the treatment of the molars with GK-101 solution as a vehicle, and thereafter were observed from 1 to 23 months. Complete retention of the sealant was observed in 81.5% of the cases, and partial detachment was in 18.5%. No caries occured in the occlusal surfaces on which the sealants had been completely retained. The partial detachment of the sealant may be due to the simple form of the pit and fissure, and also to the insufficiency of enamel for acid-etching. GK-101 solution was shown to be effective when it was used to irrigate the pits and fissures before the sealing.
To determine the optimal age for the application of the sealant,324 children who had dental records between the ages of 3 to 5 participated in this survey of dental caries prevalence. Several data were obtained. First, second deciduous molars are sealed at the age of 3, a 30% reduction in the occurence of caries can be expected in 2 years. Second, if the sealant is applied between the ages of 4y0m to 4y5m, a 10% reduction in the occurence of caries can be expected in 1 year. Third, if the sealant is applied between the ages of 4y6m to 4y11m, a 10% reduction and a 20% reduction in the occurence of caries can be expected in 1 year in the maxillar molar and the mandibular molar, respectively.

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The purpose of this study was to investigate the relationship between the biting force and the activities of masticatory muscles in children. The present report deals with the measuring points and the reproducibility as to present parameters.
Three children with deciduous dentition and three adults with permanent dentition, who had any symptoms in the gnatho-facial function, were examined. The measurement was performed three times at intervals of two or three days. EMGs were taken from the right temporalis and masseter muscles by using bipolar surface electrodes, and biting forces were measured at the right second deciduous molars in children and the right first molars in adults with aid of bite transducers placed inter-maxillary.
Six parameters were chosen for the measuring points, such as (1) maximum bite force (MBF), (2) the time of MBF (MBFT), (3) the speed of the maximum bite (MBS), (4) the time of MBS (MBST), (5) the integrated EMG of the temporalis muscle (IET), and (6) the integrated EMG of the masseter muscle (IEM). Results obtained in the present study are summarized as follows:
1 It was noticed that all parameters revealed reproducibility in both children and adults. While three parameters such as MBFT, MBS and MBST, showed some varieties among subjects and the various day of the experiment.
2 The values of four parameters such as IET, IEM, MBF and MBS were significantly lower in children compared with those of adults (p<0.005).

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S. mutans has been considered to be the most significant pathogen in dental caries of humans and experimental animals. Several studies indicated that most people, with or without dental caries, harbor S. mutans. However, S. mutans was not detectable in the oral cavity before the eruption of primary teeth. This infection with S. mutans seemed to be of intrafamilial transmission, especially from mother, based on serological and bacteriological similarity of S. mutans isolated from one mother and her children.
The purpose of the present study was to investigate the influence of inoculum size in dam-to-litter transmission, incidence of dental caries and establishment of S. mutans in experimental animals.
SPF female rats, which had harbored various numbers of S. mutans in their oral cavities, were made pregnant, and the transmission of S. mutans from dam to litters was examined. S. mutans MT8148R or 6715 was not recovered from the mandibles of 10 or 15-day old litters in any of the groups, however, both strains were recovered in 20-days old litters. There were positive correlations between the numbers of S. mutans recovered from the mandibles of litters and those of dams at weaning. Furthermore, positive correlations were shown between the occurences and severity of caries of litters with S. mutans level of dam.
The influence of inoculum size and infectious challenges on the establishment of S. mutans were examined in SD rats or ICR mice. The animals were infected with various inoculum sizes of S. mutans either once or 10 times. Infection of S. mutans with 10 challenges enhanced the establishment of S. mutan, s. markedly in rats or mice, compared with that of one infection. The establishment of S. mutans was enhanced when the animals were fed with sucrose diets.
These results indicated that the number of S. mutans in dams played a significant role in the transmission and establishment of S. mutans in animals.

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Fluoride is known to have a strongly cariostatic effect, and molybdenum is thought to have a mildly cariostatic effect. (NH₄)₂MoO₂F₄ containing both fluoride and molybdenum has been shown to prevent dental caries and also depress the severity of dental caries in experiments with rats. Furthermore, (NH₄)₂MoO₂F₄ does not discolor the teeth.
The purpose of this study was to investigate the mechanism of the cariostatic effect of (NH₄)₂MoO₂F₄ from the viewpoint of the effects on dentin. The reaction of (NH₄)₂MoO₂F₄ with dentin powder, the effect of (NH₄)₂MoO₂F₄ on Brushite and Whitlockite formation, on collagen, and on intact dentin blocks were examined.
The results were as follows:
1) Reaction of 10,000 ppmF (NH₄)₂MoO₂F₄ with dentin powder produced CaF₂ and increased F uptake more than NaF and NH₄F. It is considered that molybdenum enhance the effects of fluoride.
2) (NH₄)₂MoO₂F₄, similar to NaF and NH₄F, produced apatite in the synthesis of Brushite and Whitlockite.
3) The collagen treated with (NH₄)₂MoO₂F₄ at pH 5.5-6.0 was resistant to collagen ase.
4) (NH₄)₂MoO₂F₄ increased the acid resistance of dentin not only immediatly after the treatment but also up to 7 days after.
5) With (NH₄)₂MoO₂F₄ treatment of dentin, CaF₂ was produced and both fluoride and molybdenum penetrated into dentin. After 8 weeks, apatite crystals grew in the dentinal tubules. In summary, these results suggest that (NH₄)₂MoO₂F₄ gives cariostatic properties to dentin.

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It has been well documented that many brain-damaged children, especially the profoundly retarded and the multi-handicapped, exhibit various types of abnormal eating patterns which mainly originate in the delay in development of the oral functions. An accurate assessment of the deviating eating functions and an efficient rehabilitational technique need to be developed for those children.
In this study, a method for evaluating oral functions in the feeding of handicapped children was developed and applied to the evaluation of 73 multihandicapped children with feeding difficulties in one of the hospital's living-in units. The assessment scale consisted of 1) developmental evaluation of lips, tongue and jaw movement and,2) evaluation of swallowing, chewing and tactile hypersensitivity.
Oral movement of the subject was video-taped in an actual feeding session. The assessment, except for the evaluation of hypersensitivity, was carried out later on by using the images on the video display. The following conclusions were obtained.
1) The evaluators were able to observe repeatedly the images on the display, so that the assessment became more accurate and objective.
2) The scale was practicable and contributed towards clarifying some developmental features, obtaining information about the functional relations among the different organs and evaluating the outcome of rehabilitational training.
3) Underdevelopment of the lip closing function and that of the movement of tongue and jaw were prevalent in the group.
4) The masticatory function was underdeveloped, showing that 84% of the children examined were unable to chew at all.
5) Tactile hypersensitivity is more prevalent in the face and oral area than in other parts of the body.
6) From a developmental point of view, it was believed that lip closing function was the key to the acquirement of other oral functions in feeding.

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The present report deals with some of the results of the studies on dental treatment for the physically handicapped children, which was performed on the consignment of Tokyo Metropolitan City in 1983.
With respect to the developmental condition of the eating function based on electromyographic analysis, it was observed that the masticatory efficacy increased the better whole body developed or the better the eating function became, and that, as a result, the masticatory frequency and time and the single timeduration were able to be reduced compared to those with severe defects, indicating that the masticatory function conducted efficiently showed an intimate correlation between the development of the eating and whole body functions and the electromyographic findings.

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The purpose of this study was to investigate the effect on carious dentin after topical application of 10% (NH₄)₂MoO₂F₄. The following results were obtained.
Firstly, CaF₂ formation was found with X-ray microbeam diffraction on the surfaces of both acute (active) and chronic (arrested) caries after the application. In addition, the CaF₂ formation was identified through SEM observation.
Secondly, both molybdenum and fluoride had deeply infiltrated into carious lesion, especially in cases of acute caries. These results suggest that one of (NH₄)₂MoO₂F₄'s caries restraining effects is due to CaF₂ formation and infiltration of molybdenum and fluoride into the carious lesion.

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Mandibular movement is one of the concrete manifestations of the mandiblestomatic function, and the range of mandibular movement is determined by complex interactions of the muscles, ligaments, nerves and temporomandibular joints, etc. In order to understand the characteristics of mandibular movements shown by young children during growth, the range of mandibular movements in the area of the mandibular incisors was recorded in young children (14 cases) and adults (12 cases) using the specially designed pedodontic mandibular movement recorder, and it was examined and compared on the frontal and sagittal plane projection chart; As a result, the following findings were made.
1. Although the range of mandibular movement was different in size between young children and adults, there was observed no basic difference in the shape on the frontal and sagittal plane projection chart.
2. Young children showed more rectilinear mandibular movements than adults in the protrusive and lateral excursion and in posterior border movement.
3. The ratio of the quantity of maximum lateral and protrusive movement to the maximum jaw opening was smaller in young children than in adults when compared on the frontal and sagittal plane projection chart.

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A four year, one month old female was referred to the Pedodontic Department of H. N. G. U. to determine the possibility of improving the discoloration and amelogenesis imperfecta of her teeth.
According to her case history, she was born as a low birth weight infant and suffered from severe physiologic jaundice and infantile hepatitis after birth. The mother reported severe morning sickness, and used the hormone Luteal for prevention of abortion during pregnancy.
A medical examination revealed that the patient's growth was retarded remarkably for her age, The height and weight being 83.7 cm and 9965g respectively, and the bone age corresponding to that of a two-year-old.
The oral findings through dental examination revealed that all the deciduous teeth were discolored. Amelogenesis imperfecta was evident in the lower and upper canines, first primary molars, and second primary molars.
In the measurements of the teeth and the dental arch, the mesiodistal distance of the tooth crowns and the length of the dental arch were within normal limits but the width of the dental arch remarkably narrow. The overjet was 4.7 mm and the overbite was 3.65 mm.
An orthopantomogram showed that the growth of the tooth germs of the permanent teeth had been retarded by one year but number of permanent teeth was normal.
According to X-ray cephalometric analysis, labio-inclination of the upper central incisors was evident in the denture pattern. On the other hand, concerning the skeletal pattern, the amount of the cranial growth had a tendency to be very small on the whole.
The authors recognize that the patient had been born with a low birth weight and had suffered from infantile hepatitis during infancy. In this case, it is interesting to consider a possible relationship between fetal diseases and the diseased of newborn infants as well as dental developmental abnormalities such as teeth discoloration and amelogenesis imperfecta.

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The Coffin-Lowry syndrome is an established inheritable syndrome. It is characterized by mental retardation, characteristic facial forms and various skeletal anomalies. The two brothers in this report exhibited clinically short stature, coarse faces and large and rather soft hands. The puffy, lax, tapering fingers are virtually diagnostic stigmata of the Coffin-Lowry syndrome.
We are reporting in this paper on the two brothers with this syndrome and their mother who also exhibited the same syndrome, but as a rather mild phenotype. The phenotypical and radiographic findings were as follows:
1. The two boys have exhibited mental retardational development.
2. Their mother is also mildly affected.
3. The two boys were small stature.
4. The elder brother exhibited large soft hands, pectus carinatum, lax ligaments and anomalies of the vertebrae.
5. They demonstrated peculiar facial forms, such as thickened supraorbital ridges, thickened zygomatic arches, antimongoloid slant of eyes, hypertelorism, broad nasal bridge, thick nasal septum and anteverted nostrils.
6. They also showed thickened prominent lips with a pouting lower lip, a prominent chin and large protruding ears.
7. X-ray studies have revealed tufted hyperplastic terminals, which appeared phenotypically as drumstic-shaped fingers.
8. They demonstrated open mouth with deep central lingual groove.
9. Malocclusion was found in both brothers.
10. There was bilateral winging of the upper central incisors, associated with diastema.
11. Eleven congenitally missing teeth were confirmed in the elder brother by radiographic examination.

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The report is a case of 3-year-7-month-old male patient with protracted neonatal Graves' disease which required a long-term treatment over a period of 2 years 6 months.
Growth impediment, early ossification of the skull and carpal bones, and eruptive acceleration of the teeth were not observed. Only a slight mental retardation was recognized.
Facial and oral findings were:
1) C|C were congenitally missing. Numerical and developmental anomalies of the permanent tooth-germs were not observed.
2) ECB|BCE showed anomalies in the size, especially C|C were cone-shaped teeth. They were smaller than average -2SD in the mesio-distal width.
3) E|E/EDC|CDE has a hypoplastic line in the enamel surface, and E|E/E|E had enamel hypoplastic area.
4) The lower right second deciduous molar had three roots. Other teeth did not show anomalies of the roots and pulp chambers.
5) Myopathy face and excessive facial hight were recognized.
6) The palate showed a particular form.
7) Both of the crystalline size and lattice defects of the enamel of |E with hypoplasia were larger than those of the control, normal enamel.

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A new disorder of the leukocyte function was described by Miller et al. in 1971, when it was identified as a lazy leukocyte syndrome.
In this paper we are reporting on another case of this syndrome. Case Report
A female patient,3 years of age with a lazy leukocyte syndrome was refered to the Pedodontic Clinic, Osaka Dental University. The chief complaints, as explained by the mother, were gingival recession and bleeding.
Her family history was unremarkable. Oral examination revealed a complete primary dentition. However, all primary molars were covered with unsuitable metal crowns and all anterior teeth were affected by extensive carious lesions.
The gingival tissue was inflamed and hemorrhagic. Dental radiographs indicated medium bone loss and a deficiency of chemotaxis was observed whereby neutrophils from the peripheral blood have normal phagocytosis. Treatment consisted of prophylaxis and routine restorative dentistry. All anterior teeth were filled with composite resin and all molars were covered with new suitable metal crowns.
Routine prophylaxis was stressed to the mother to keep the gingival inflammation under reasonable control.
Up to the present, her gingival condition has been improving.

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We experienced a case with continuous gingival bleeding caused by steel crowns with extremely poor marginal adaptation in a 5 year 4 month thrombasthenial boy. The patient experienced gingival bleeding which continued for 8 days in spite of transfusion of PC and pressure hemostasis with bosmin gauze, and was referred to our hospital for treatment.
The gingival bleeding was seen from the cervical area of the lower right primary molars having extremely poor cervically adapted steel crowns. The steel crowns were removed and the gingival area was rinsed carefully with acrynol solution. The bleeding was then easily stopped and has not occurred since.
All dental treatment was performed under AMCA control (1200 mg/day)and PC was not transfused while he was in the hospital for 6 days.
Three primary molars were extracted under local infiltration anesthesia and sutures, surgical packs, and acrylic sprints were used to control bleeding. Adequate hemostasis resulted three hours after the extraction and the acrylic sprints were removed.
Pulp and root canal therapies were applied to three primary molars and crown restrations were applied to seven primary teeth.
A denture-type removable appliance was applied to the extracted mandibular first primary molars portion. Since the space closure occurred after the extraction, the removable orthodontic appliance was applied to the extracted maxillary second primary molar portion when the eruption of the maxillary first molar was finished.

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A report was made of a 3 year and 9 month old girl with the Kleeblattschadel (clover leaf skull) syndrome. She had a grotesque trilobed skull with bulging at the frontal and temporal parts of the cranium. It was caused by synostosis of the posterior part of the saggital suture; lambdoid suture and coronal suture, and hydrocephaly. Furthermore, exophthalmos, downward displaced ears, deeply recessed nasal root and shortening of the extremities were present. In addition to these general findings, this case also disclosed the following dental findings:
1) Roentgencephalometric analysis revealed hypoplasia of the maxilla and the body of mandibula, and relative mandibula prognathism.
2) Hypoplasia of the maxilla led to such severe cross bite that the upper and lower incisors could not bite against each other. Hypoplasia of the max i l la and mandibula led to shortening of the width and length of both the upper and lower dental arches.
3) The palate had a marked median furrow.
4) Eruption of the upper second primary molars was delayed for a short period.

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In 1954 Bloom first described the Bloom syndrome, which was characterized by congenital telangiectatic erythema, sun sensitivity of the skin and low-birthweight dwarfism, about 100 cases of this syndrome have been reported on throughout the world and about 6 cases in Japan. However few oral minifestations have been described in the reports.
Two sublings with the Bloom syndrome, a 12-year-old boy and a 10 yearold girl requiring dental care, had been refered to the Pedodontics, Asahi Univ. Hospital.
The following are the dental findings.
1) General findings:
The two sibling patients were bone from the parents of a consanguineous marriage. Three typical symptoms associated with this syndrome, as described above, were seen in both patients. Marked retardation in physical growth both height and weight of the body were noticed, this being more prominent in the elder brother.
2) Oral findings:
Congenital missing of the lower bilateral canines in the elder brother was observed and generally smaller tooth size was characteristic. Also either the length and the width of dental arch, and basal arch were measured to be smaller when compared with the normal, while in the younger sister, the tooth material was shown to be within normal 1 S. D. values except for lower first molers.
3) Cephalometric findings:
Retardation of the growth of the gnatho-facial bone was recognized in both cases as well as seen in the physical growth. Particularly marked retardation was observed in the mandibularbone. Affects of the Bloom syndrome on the maxillo-facial and oral cavity were considered to be more evident in the elder brother than in the younger sister.

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