The present study was conducted to produce the latest cephalometric standards of Japanese children. Materials consisted of 329 lateral cephalograms and 274frontal chphalograms taken from Japanese children with clinically normal occulusion, supplied from the Departments of Pediatric Dentistry of dental colleges and universities in Japan. Variations of angular and linear measurements, and XY coordinates calculated from the laterl cephalograms were compared with the past data, Iizuka, Sakamoto and Ono, taken in the 1950s.
Environmental factors which brought about a remarkable increase in the height of Japanese children, also influenced many parts of the maxillofacial cranium in two ways, i. e. the increase in length and the phenomenon of accelerated development. The increase in length was observed more clearly in boys, however, the phenomena of accelerated development was observed more clearly in girls.
Dividing the maxillofacial cranium into depth and height, the increase in length was more marked in height. The increase in depth was more than the corrected values, which were estimated using the allometry between the standing height and lengths of the maxillofacial cranium, at the anterior cranial base in all of the observation periods. Also at the nasomaxillary complex, the increase in depth was more than the corrected values only after the mid mixed dentition periods. However, at the mandible in most periods, the increase in depth was less than the corrected values. On the other hand, the increase in height was more remarkable in the posterior facial height than in the anterior facial height. The morphological changes to adults, concerning both the axes of the upper and lower central incisors and the outer frame of mandible, as phenomena of accelerated development, were observed after the mid mixed dentition period.
With the results calculated from the frontal cephalogram, the growth patterns of the neighboring parts were compared between width and depth at the neurocranium, the upper face and the lower face. Their growth patterns were almost the same, but the growth in width preceded the growth in depth. The increase in width were especially prominent in the lower face.

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Fine structure of the epithelial remnants in the gubernacular canal of a crab-eating monkey at the primary occlusion stage was examined by light and transmission electron microscopy.
The epithelial remnants of the dental lamina from successional touth germs were seen throughout the gubernacular canal and up to the gubernacular foramen. The epithelial cells were surrounded by a basal lamina and were joined to one another by poor desmosomes. The cell membrane had hemidesmosomes that were seen along the basal lamina, and microvilli that interdigitated with those of the adjacent cells. The tonofilaments surrounded the nucleus, and some of them were joined to the desmosome and hemidesmosomes. This fine structure of the epithelial stands was similar to the epithelial remnant of Malassez. The epithelial cells near the tooth germ had numerous ribosomes and mitochondria. The rough-surfaced endoplasmic reticulum was not developed. In most parts of the sections examined, only a small number of atrophied epithelial cells was observed. However, among the epithelial cells near the gingival mucosa, we observed cells containing swollen mitochondria, dilated rough endoplasmic reticulum, and condensed tonofilaments, abnormalities which probably occurred due to the degeneration of the cells. There was a difference in fine structure between the two areas. Cellular debris apparently derived from the epithelial cells was observed within the extracellular spaces of the connective tissue. On the other hand, hemidesmosomes did not appear to be affected by the degeneration.
The presence of these highly specific intracellular and extracellular components suggests the existence of some specific activity that probably includes the maintenance of the bony canal.

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The purpose of this study was to investigate of the factors that influence the clinical effect of the sedation with intranasal administration of midazolam combining nitrous oxide/oxygen inhalation for handicapped patients during dental treatment.
Nineteen mentally handicapped patients, aged 5 to 20 years, all of whom had previously exhibited highly combative and resistant behavior toward dental treatment under nitrous oxide/oxygen inhalation sedation, were administered either 0.2 mg/kg or 0.3 mg/kg intranasal midazolam. The patients then received dental treatment combining nitrous oxide/oxygen inhalation (20-40% N₂O/80-60%O₂).
They were distributed into two groups. The first group was the effective group of 10 patients with intranasal sedation and the second group was the ineffective group of 9 patients with intranasal sedation. The calendar age, weight, sex, diagnosis of handicap, dose per weight, total volume of dose, time length of dental treatment and developmental age were compared between the two groups. A summary of the results is as follows:
With all factors except the calendar age and diagnosis of the handicap, there were no significant differences between the two groups. The average calendar age of the effective group was 15 years and 10 months, and that of the ineffective group was 10 years and 6 months. There were significant differences between the average calendar ages of the two groups. The ratio of autistic patients in the ineffective group was significantly larger than that in the effective group.

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The purpose of this study was to investigate the influence on the changes of urinary catecholamine levels when applying the sedation with intranasal administration of midazolam combining nitrous oxide/oxygen inhalation during dental treatment.
The subjects were 22 mentally retarded patients who received no medication such as anti-seizures or tranquilizers by order of their physician. They were distributed into three groups. The first group was the intranasal sedation group of 9 patients (Ave. age: 14.5±5.7 years), who exhibited combative behavior during the previous dental treatment under the nitrous oxide/oxygen inhalation sedation, but who underwent dental treatment with cooperative behavior with this method. The second group was the inhalation sedation group of 8 patients (Ave. age: 10.9±4.6 years), who underwent dental treatment with cooperative behavior under nitrous oxide/oxygen inhalation sedation. The third group was the restrained group of 5 patients (Ave. age: 7.7±1.2 years), who exhibited combative behavior during dental treatment under nitrous oxide/oxygen inhalation sedation, and who underwent restrained dental treatment under nitrous oxide /oxygen inhalation sedation.
The urinary samples for analysis were collected before and after dental treatment. Dopamine, noradrenaline and adrenaline were isolated from the urine, and quantitative analyses were performed. The pre- and post-dental treatment urinary catecholamine levels were compared among the three groups. The ratios of the post-treatment catecholamine levels for the pre-treatment catecholamine levels were calculated as the conversion ratio. A summary of the results is as follows:
The post-treatment levels of adrenaline and noradrenaline for the restrained group were significantly higher than those for the intranasal sedation group and inhalation sedation group. In the post-treatment levels of adrenaline, noradrenaline and dopamine, there were no significant differences between the intranasal sedation group and the inhalation sedation group. The conversion ratios of the adrenaline for the restrained group was significantly higher than those for the other groups.
Applying sedation with intranasal administration of midazolam combining nitrous oxide/oxygen inhalation for uncooperative mentally retarded patients during dental treatment markedly suppresses the secretion of catecholamine.

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Fourty Class 1 and Class 5 cavities were made on extracted primary teeth using the air-powder abrasive system KCP-2001J.
For the purpose of observing the outline form and detailof the cavity, replicas of the cavities were made using composite resins with or without etching, primer and bonding agent, The replica was observed by SEM.
The following conclusions were obtained.
1. The Replicas of the air-powder prepared cavities, showed the following characteristics, a slight rounded carvo-surface margin and a smooth cavity wall, without a distinct line angle on the cavity wall to the cavity floor. No smear layer was observed on the cavity floor.
2. Two types of outline form of the replica were observed, with one peak on the central portion of the cavity floor and with two peaks on the mesial and distal portion of the cavity floor.
3. In the experimental group with the primer and bonding agent, penetration of resin into the dentinal tubles was observed in detail.
4. In the experimental group with the etching agent, resin tags were observed on the carvo-surface enamel. Rather long resin penetration into the dentinal tubles was also observed in detail on the cavity floor.
5. Etching of the cavity is considered also useful for the adheasion of resin to enamel and dentin even in air-powder abrasive cavity preparation.

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The concentration of calcium, phosphate and hydroxyde in a solution affects the degree of saturation with respect to the enamel. The effect of calcium concentration in preventing enamel demineralization was investigated in this study. Three thin sections,140μm to 160μm thick, were cut out from each of nine human premolars. All surfaces of the sections, except for the original enamel surface, were coated with nail vanish. These sections were immersed in demineralizing solutions for one week at 25°C.
The compositions of the solution was 0.1 mol/L lactic acid,23 mmol/L monobasic potassium phosphate,3 mmol/L sodium azide and the pH value was 4.4. The concentration of calcium chloride was 7,14 or 21 mmol/L in the three solutions. After 1 week, the degree of demineralization was determined by image analysis of contact micro-radiograms from each section. A big sub-surface lesion was observed in the solution with 7 mM calcium. The area of the subsurface lesion decreased in accordance with the increase of calcium concentration from 7 mM to 14 mM. The calcium concentration of 21 mM in the solution caused almost no demineralization in the enamel. The results revealed that increase of calcium concentration alone can prevent enamel demineralization even though other conditions such as pH were exactly the same.

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The purpose of this study was to determine the difference of the arch form and occlusion in the permanent dentition between the spontaneous closure group and the group with the continually open bite in the late primary dentition of the deciduous anterior open bite cases. The materials used in this study were the serial plaster casts of 36 children with deciduous open bite caused by thumb-sucking, and they were measured with the three dimensional system. In addition, it was examined in evaluating the error in the fit of the spline whether the cubic spline function is useful in representing the dental arch form or not.
The following results were obtained:
1. The permanent upper central incisors of the group with the continually open bite remained noticeably inclined to the labial side in the permanent dentition, and the horizontal over-jet was larger than that in the control group.
2. The open bite localized in the central incisors which had been generated after the complete eruption of the upper central incisors remained the open bite in the permanent dentition phase in the group with the continually open bite. It is thought that insufficient increase of the intercanine width and insufficient forward growth of the anterior alveolar bone in the group with the continually open bite caused the insufficiency of the anterior available arch length, which hindered the upper central incisors from inclining to the palatal side.
3. The cases in which the over-jets were much larger in the deciduous dentition in the spontaneous closure group have the potentials to turn the deep over bite in the permanent dentition.
4. The height of the palate in the permanent dentition was not affected very much by the deciduous open bite. The lower arch was also not influenced much except for the extrusion and inclination of the central incisors to the labial side.
5. The anteroposterior curves of the occlusion of the upper arch in the permanent dentition were larger in the group with the continually open bite compared with the control group. Also the group with the continually open bite have the potentials to turn high canines.
6. The recovering from the deciduous open bite, the recovering of the arch form and the position of anterior alveolar bone as well as closure of anterior teeth is necessary to occur by the term of the increase of intercanine distance or before the eruption of the upper central incisors.
7. The use of the cubic spline which was computed by applying the N-spline and the divided difference is a very useful method for representing the arch form.

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4^G-β-D-galactosylsucrose (O-β-D-galactopyranosyl- (1→4)-O-α-D-glucopyranosyl-(1↔2)-β-D-fructofuranoside) is one of the trisaccharides and it has the function of improving the condition of the microflora in the intestines.
The purpose of this study was to investigate the metabolism of 4^G-β-D-galactosylsucrose by oral streptococci.
1) Streptococcus oralis ATCC 10557 grown in either 4^G-β-D-galactosylsucrose -broth and galactose-broth showed the highest rate of acid production among the four strains of oral Streptococci (S. mutans 6715, S. gordonii Challis, S. sanguis ATCC 15914, S. oralis ATCC 10557) when 4^G-β-D-galactosylsucrose was used as a substrate.
2) Resolution of 4^G-β-D-galactosylsucrose by S. oralis ATCC 10557 started from hydrolysis at the β-D-galactoside bond by the induced β-D-galactosidase.
3) The activity of the β-D-galactosidase with S. oralis ATCC 10557 increased within 5 minutes after addition of 0.2% galactose, lactose, or 4^G-β-D-galactosylsucrose to the medium.
4) The activity of the induced -galactosidase was highest in the cell membrane fraction of S. oralis ATCC 10557 grown in the 4^G-β-D-galactosylsucrose -broth.
Conclusion: β-D-galactosidase was induced at the outside of the cell membrane of S. oralis ATCC 10557 within 5 minutes after addition of 0.2% 4^G-β-D-galactosylsucrose to the medium.4^G-β-D-galactosylsucrose was utilized as a carbon source for acid production by S. oralis ATCC 10557.

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The objective of this study was to compare the acidogenic potential of various sweeteners using a new plaque pH monitoring system which allows rapid. sequential analysis in the same plaque, to evaluate the effect of repeated exposure to lactose on the rate of human plaque acid production, and to determine if enzymes involved in lactose metabolism could be induced in dental plaque.
Three human subjects wore appliances containing miniature ion-sensitive field-effect transistor (ISFET) pH electrodes positioned on the buccal tooth surfaces. After 4 days of plaque accumulation 100μl of 2% solutions of sweeteners were sequentially applied to the plaque covered electrodes and the rate of acid production was determined by monitoring the pH for 5 minutes. Between each exposure the subjects chewed wax to return the pH to resting levels.
The first two tests and a final test were always with sucrose or glucose since the rate of acid production with the fist exposure was lower compared to those with the second and the last exposure. For sweetener comparison the results from final sucrose exposure(3.2±1.0×10_-6mol/min)were not significantly different from the second rinse(3.3±1.2×10_-6mol/min). When compared to sucrose (100%) the rate of acid production by fructose (56.9%), lactose (16.9%), sorbitol (1.3%) and Palatinose (1.1 %) were consistent.
When lactose was exposed sequentially the rate of lactose conversion to acid was shown to be 1.7±0.2 times higher after a second exposure to lactose and 2.8±0.6 times higher after a third, while the rate of acid production from glucose or sucrose was consistent within a Dlaaue over 5 to 6 cycles. The activity of phospho-β-D-galactosidase (P-β-gal) increased from 16.8±2.4nmol/min/mg protein in plaque samples obtained prior to rinsing with lactose to 35.6±10.4in samples obtained 20 min after rinsing. β-D-galactosidase(β-gal)showed similar activities before 63.9±12.8nmol/min/mg protein and 59.6±7.6 after rinsing.
Lactose-fermenting bacteria were isolated from the plaque on the microelectrodes and identified as Streptococcus sanguis, Streptococcus oralis and Streptococcus gordonii. All of the isolates possessed detectable β-gal activity which was not elevated by lactose and P-β-gal activity which was inducible. The rate of acid production from lactose was shown to increase with elevated P-β-gal activity. Lactose causes an elevation in P-β-gal activity in plaque and specific plaque streptococci may be responsible for a portion of this increase.

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The purpose of this study was to confirm whether some inbred mice have GSR on the mandibule molars including the first, the second and the third molars (M1, M2 and M3) or not, and to investigate the differences of the incidence rates among total of 34 strains observed with binocular microscopic and histologically findiys. Also the effect of genetic factors on the morphogenesis of the GSR on M2 molars in mice was observed using 34 inbred mouse strains.
The following were the results of the present investigation.
1) The GSR appeared only on the root of the second mandibular molars (M2)in five strains of inbred mice, AKR/J, C3H/HeJ, C57BR/CDJ, C57L/J and RF/J. Since both C57BR/CDJ and C57L/J had a 90-100% frequency for the occurrence of GSR with a high rate of bilateral and no significant sexual differences, it was thought that the genetical factors could be playing an important role in inducing the GSR.
2) Definite trends were observed in the correlation between the frequency for occurrence of GSR and the origins of strains in C57BR/CDJ and C57LJ. It has been supposed that the mouse GSR do present a more eminently degenerative phenomenon through the action of some chromosomal factors from the morphological point of view.
3) It is considered that the mouse GSR, of which the buccal half is separated but the lingual one is not, is very similarity to the human GSR in terms of morphological aspects such as the root canal types of GSR and the degree of the fusion of the root.
Finally, it seems possible that two strains, C57BR/CDJ and C57L/J, offer themselves as candidate animals for GSR models.

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The apical radiographs of 98 pulpless mandibular primary molars of children aged 3-6 years were examined with respect to the abnormal root resorption, periapical lesions and its involvement of both the bifurcation areas and the permanent tooth-buds.
The mesial and distal roots of each tooth were separately recorded on the periapical lesions and the abnormal root resorption. They were divided into four classes as follows. Forty-nine roots were designated as periapical lesions (-)root resorption (-),23 roots as periapical lesions (+) root resorption (-),12roots as periapical lesions (-) root resorption (+) and 112 roots as periapical lesions (+) root resorption (+).
For the pulpless teeth without the abnormal root resorption, inflammatory involvement of the bifurcation area extending from the periapical lesion was observed in 4 teeth out of 8. For the pulpless teeth with the abnormal root resorption, inflammatory involvement of the bifurcation area was observed in 69teeth out of 90.
The inflammatory involvement of the permanent tooth-buds was observed in 15 cases; 14 were found to be accompanied by bifurcation involvement and one was not.
These observations indicate that both the periapical lesions and the abnormal root resorption advance over a short period of time, whether either of which precedes the other. The abnormal root resorption may facilitate the passage of microorganisms and their derivatives through the enlarged apical foramen to the periapical tissue, leading to the possible involvement of the furcation area. In the early stages of these series of the events, the periapical lesion seems to progress lenearly along with the periodontal space, instead of expanding like a concentric circle.

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The occurrence of a transitory increase in temperature with every visit to an out-patient dental clinic is uncommon.
The case of a 3 year and 2 month girl showed this type of fleeting elevation of temperature at our dental clinic and afforded in opportunity to investigate its etiology.
1. The parents were extremely shocked when her elder sister died suddenly from Reye syndrome, and after that they came to distrust medical treatment.
2. On the day when she visited the clinic the patient, having normal temperature at home, showed an elavation of temperature at the dental clinic, but her temperature was back to normal when she returned home.
3. During dental treatment the patient was quite cooperative and did not cry.
4. The elevation patterns of the temperature during the dental procedures with and without a local anesthetic were the same.
5. As soon as her father approached the dental chair and talked to the dentist, her temperature rose.
6. Three kinds of psychological tests given to the parents indicated that they had intendency to dote on her, but her father showed extreme inconsistency (contradiction) in his attitude toward bringin, her up.
We diagnosed the case as psychogenic fever.

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The patient was a 2 year 4 month old boy. On June 13,1989, he was playing in the bathroom when he was held between his teeth and he could not remove his mouth from the tap. His mother helped him to remove from the tap and his cheek, the submandibular, submental, neck and proodial region began to swell out. On the next day, a dental examination was made check. The submandibular, submental, neck and preordial region had redness and diffusey swelling but had no crepitation. He had a wound on the floor of mouth but had no bleeding. A CT scan was made and it suggested that tap water existed insubcutaneous and in the tissue region from the cheek to the upper chest widly and diffusely. Anti-biotics, anti-inflamatory agents were administrated and the patient was treated with warer. Swelling improved after 6 days and disappeared after 8 days.

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In recent years, traumatic injury to young children has shown a rising tendency and total evulsion of primary anterior teeth has also been observed.
For the loss of one or two primary incisors, a removable space maintainer or movable pin & tube type space maintainer are thought to be appropriate.
However, depending on the patient, a removable space maintainer is difficult to manage and also is often easily damaged.
Meanwhile, for the former movable pin & tube type space maintainer, preparation of the abutment primary teeth is necessary before placing pre-made metal or jacket crowns even when they are healthy teeth.
Therefore, at this time, we tried to manufacture a fixed space maintainer using a pin & tube with mesh plates which can be fastened to non-prepared primary abutment teeth using adhesive resin and made an attempt to apply them clinically.
10 patients having one maxillary primary central incisor loss were selected for the object of this study.
In these patients, lateral enlargement of their dental arrangement due to growth and movement of the pin & tube section was observed.
In 2 patients out of 10, a smooth transition to successive permanent teeth has also been observed.
These results suggest that this adhesive bridge is excellent both in function and appearance and has a multitude of possibilities for clinical application.

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Deciduous canines are generally single rooted. The present case report describes a primary dentition with four birooted primary canines, which is extremely rare.
A six-year 4-month old boy was brought to the Pedodontic clinic, Tokyo Dental College Suidobashi Hospital with a chief complaint of swelling in the maxillary right quadrant. The child showed normal development. His elder brother and parents were negative in terms of medical history or dental anomalies.
The clinical and radiographic findings were as follows:
The patient was in stage Hellman's dental age III A, in the development of the dentition classified by Hellman. He showed normal development mixed dentition.
The clinical crowns were normal in appearance. The mesiodistal widths of the maxillary deciduous canines were a little larger than the regular size, and the mandibular deciduous cannines were the standard size.
Radiographic examination revealed two separate roots on each maxillary and mandibular bilateral deciduous canine. Therefore, all deciduous canines were found to be birooted. No other dental anomalies were detected with exception of impacted supernumerary teeth in the maxilla. Both roots were approximately of equal shape and size. Each root of these canines was narrow apart in comparison with the deciduous molar apart.
In this case, each deciduous canine appeared to have definite single pulp chamber, but separated mesial and distal root canals.
Cases of maxillary and mandibular bilateral deciduous canines with two roots are extremely rare. Only two reports have been published since 1978. The etiology of this condition is unknown.

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We experienced an infrequent case of unilateral buccoversion of the mandibular first molar after eruption of the sceond molar.
The case was a 20 year old woman. She had been examined and dental casts were taken longitudinally at two-month intervals since she was 3 years old. She had normal occlusion in the deciduous dentition and had not suffer from any premature loss of deciduous or permanent teeth. Both sides of the mandibular second premolar were congenitally absent and both sides of the mandibular second deciduous molar still remained. The maxillary dentition was nearly normal. The mandibular arch showed infraversions of both sides of the second deciduous molar and slight crowding on the anterior teeth. The mandibular right and left first molars were also in a nearly normal position before eruption of the second molars. However, the mandibular right first molar subsequently changed to the buccal side.
The following measurements were made on the longitudinal mandibular casts:
1. Distances from midline to the cervical midpoint of the lingual surface of the first molars.
2. Distances between the mesial contact point with the second deciduous molar and the distal contact point with the second molar of the first molar.
3. Vertical differences between the distal marginal ridge of the second deciduous molar and the mesial marginal ridge of the first molar.
4. Distances from the contact point of the right and left permanent central incisors to the cervical midpoint of the lingual surface of the first premolars, second deciduous molars, first molars and second molars. From the results of the measurements and examination of dental casts and
X-ray photographs, two differences between the right and left side in the dentition or occlusion were recognized. These was the difference of the connections between the most distal point of the second deciduous molar and the most mesial point of the first molar. Occlusal contacts on the right side were previously lost on lateral segments, while the occlusal contacts on the left side were kept.
We considered that these differences were the reason that buccoversion of only the right mandibular first molar occurred after eruption of the second molars.
This case report indicates a possibility of local malocclusion which occurs after eruption of the second molars.

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Seven immature premolars were treated with endodontic therapy due to central cusp fracture at the Pedodontic Clinic of Niigata University Dental Hospital during a period of 14 years and 9 months from September 1979 to June 1994. We investigated these cases clinically and radiologically.
The results were as follows:
1. The observation period ranged from 8 months to 7 years and 5 months.
2. The ages of the patients at the first examination ranged from 9 years and 2months to 12 years and 7 months.
3. Five cases were affected on the lower second premolars, one involving the upper second premolar and the other the lower first premolar. The state of root formation at the first examination ranged from 2/3 to 3/4 of root length.
4. Treatment included vital pulp amputation with Calvital in one tooth, and root canal filling with Vitapex after pulpectomy or infected root canal therapy on each of the three teeth.
5. Based on X-ray examination, in the case of vital pulp amputation, hard tissue formation at the amputation site was observed after about 3 weeks, then growth of the root with apexogenesis was recognized. In the cases of pulpectomy, two of the three teeth showed root extension after apical closure by the hard tissue. However in the cases of infected root canal therapy, only apexification was observed except for the growth of the root. Also the dose of hard tissue added to the root apex depended on each individual case.
6. It is suggested that apical closure or growth of the root could be accomplished by early detection and adequate treatment for the central cusp fracture of premolars.

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It is said that submerged teeth are located at lower position from a existing occlusal plane. This is a report of a case of a submerged deciduous molar which underwent periodic observation for a long period.
The patient was a 2 year 4 month old male. His chief complaint was eleven missing teeth lost due to clenching. The family history and general condition levealed nothing particular. He had entered the hospital for 3 months due to scalding of body and limbs at 1 year 9 months of age. While he was in the hospital, he had lip and clenching habits due to restraining of the body.
Also, this patient had a submerged upper left first deciduous molar which was impacted under the gingiva after 5 years 4 months from the first visit to our dental hospital. This tooth was extracted because of the disturbance in the eruption of the succeeding tooth and a histo-pathological observation was performed. Hard tissues like alveolar bone attached to the root of the extracted submerged tooth was recognized with H. E. staining.

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