This study was carried out to investigate the effectiveness of intravenous flunitrazepam administration with or without inhalation sedation using N2O-O2in dental treatment of handicapped patients.
Sixteen handicapped patients, aged 2 to 19 years, were treated under sedation of flunitrazepam with N₂O-O₂. A total of 20 dental treatments were performed on the 16 patients. Seventeen patients, aged 4 to 19 years, were treated under sedation using flunitrazepam without N₂O-O₂, there being a total of 25dental treatments performed on them.
The following results were obtained.
1) The dosage for patients treated under sedation using flunitrazepam with N₂O-O₂ was 0.029-0.051 mg/kg (mean 0.039 mg/kg) flunitrazepam. The concentration of N₂O was 50%. The dosage for patients treated under sedation using flunitrazepam without N₂O-O₂ was 0.021-0.081 mg/kg (mean 0.038mg/kg) flunitrazepam.
2) The evaluation of the sedative effect of flunitrazepam with N₂O-O₂ resulted in the following 3 types: markedly effective 70.0%, effective 25.0% and slightly effective 5.0%. The evaluation of the sedative effect of flunitrazepam without N2O-O2 resulted in the following 3 types: markedly effective 48.0%, effective 48.0% and ineffective 4.0%.
3) Flunitrazepam without N₂O-O₂ was found to lessen markedly the involuntary movement associated with cerebral palsy, and to be effective with respect to the anxiety of patients who had slight mental retardation. Flunitrazepam with N₂O-O₂ was found effective, not only for cerebral palsy and mental retardation, but also for autistic tendencies.

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The purpose of this study was to compare the relative cytotoxicity of dental amalgams and to determine how their toxicity depends on the amalgam composition and the aging time, by means of a rapid and sensitive in vitro cell culture test.
Three high copper and one low copper commercially available amalgams were used in this study. Amalgams were triturated according to the manufacture's recommendation, filled into g1ass tubes(ID 4mm×1mm high), and aged for 1hour,24 hours,7 days, and 30 days before testing.
Fibroblasts,5ml of 1×10⁵ cells per ml in Eagle's MEM with 10% FCS, penicillin(100 μ/ml)and streptomycin(100μg/ml)were evenly seeded on a cover g1ass in a tissue culture dish and incubated for 24 hours at 37°C in a humidified atomosphere with a 5% CO₂, in the air. The medium was replaced with 5 ml of agar overlay medium consisting of 10% FCS, Eagle's MEM and 1.5% agar. Glass tubes(n=8)filled with the test amalgams were placed at the center of the agar, and incubated for 24 hours in 5% CO₂ in the air at 37°C. After 24 hours incubation, the cover glass was removed and cells were fixed in a 10% neutral formalin and then stained with H. E. to differenciate the areas of affected and unaffected cells around the amalgam specimens. The affected area was quantitatively determined using an image analysis system. Dispersalloy (zinc-containing high-copper amalgam) showed higher cytotoxicity than any other amalgam. Lumi Alloy (high-copper amalgam) showed the same cytotoxicity as Hi-Atomic M(low-copper amalgam). Spherical D (high-copper amalgam) showed the least cytotoxicity among the amalgams tested. Zinc was the major contributor to the cytotoxicity of the amalgam. The cytotoxicity of the amalgam decreased with aging time, possible due to the surface oxidation of the amalgam which prevents the dissolution of the elements most responsible for the cytotoxicity, such as zinc.

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The purpose of this study was to examine the inhibitory effect on enamel demineralization of initial caries with laser irradiation only and with fluoride application.The materials were the extracted human young premolars with artificial caries like lesions produced by exposure to demineralizing fluid (0.1 M lactate buffer containing 6% hydroxy ethyl cellulose) on the enamel surfaces.
The methods of this investigation were as follows.
Experiment 1: Each of those lesions were exposed to an acousto-optically Q-switched Nd-YAG laser under conditions of 66.9 J/cm2,47.8 J/cm² or 28.7 J/cm²energy. After these lased lesions had been exposed to 1 ml HClO₄ solution (0.5 M)for 20 seconds 5 times, concentrations of Ca in each HClO₄ solution were determined. On the other hand, other lased enamels were observed with SEM after demineralized with 0.1 M acetate buffer solution.
Experiment 2: Artificial caries like lesions were treated as follows. Group 1; Not treated. Group 2; AO Q-sw Nd-YAG laser was irradiated with 66.9 J/cm² energy. Group 3; APF was applied for 4 minutes at 37°C. Group 4; AO Q-sw Nd-YAG laser was irradiated after APF application. Group 5; APF was applied after AO Q-sw Nd-YAG laser irradiation.
All those lesions were then etched with 1 ml of 0.5 M HClO₄ solution and concentrations of Ca and F dissolved in each solutions were determined. The surfaces of each treated lesions were observed with SEM after demineralized with 0.1 M acetate buffer solution.
The results were as follows.
1) The acid-resistance of artificial caries-like lesions increased significantly when the lesion was irradiated by 66.9 J/cm² or 47.8 J/cm² AO Q-sw Nd-YAG laser. Cracks produced by 66.9 J/cm² laser irradiation were deeper than those by 28.7 J/cm² laser irradiation.
2) APF application on the artificial caries-like lesions after laser irradiation was most effective for inhibiting enamel demineralization, but the F concentration was highest in those which were exposed to laser irradiation after APF application. It seems that there were fluoride-rich reaction products on enamel surfaces of which was treated with APF application.

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The purpose of this study eas to evaluate the reproducibility of the Ricketts method of analysis applied to children during the period of primary dentition, that is to say, to find out whether the Ricketts analysis produces different results according to the measuring points or the measurment items used, or according to differences in the skills of the analyst, or if the measurements are made on different days or on children of different ages, that is, in different stages of dental calcification. A total of 31 standard radiographs were used in the study: 6 driedneurocranium radiographs and 25 lateral cephalometric radiographs of the outpatients selected among those treated at hospital of the Pedodontics Department 754of the University. The examinations were performed using three different types of analysis, viz., ternary arrangement-dispersion analysis, quaternary arrangementdispersion analysis, and difference-examination of the dispersed inter-analyst errors. The following results were obtained:
1) In the group with dried neurocraniums, significant differences due to interanalyst factors were observed in Basion in the direction of the X-axis and in Nasion, Points A, PA and B6 in the direction of the Y-axis. In other aspects, no significant differences were observed either in relation to interanalyst or inter-date (of mesurement) factors, and thus reproducibility was considered good.
2) In the group of child patients, significant differences due to inter-analyst factors were observed in ANS and PNS in the direction of the X-axis and in PNS in the direction of the Y-axis. Regarding other mesuring points, no significant differences were observed either in relation to inter-analyst or inter-date factors, and thus reproducibility was concidered good.
3) The analysis of differences in the dispersion of inter-analyst errors did not reveal any tendency towards a greater degree of difficulty of analysis as the patient's age increased.
4) With regard to the Ricketts analysis items, significant differences, due to inter-analystfactors in canine relation, upper-lip length and maxillaly height, were observed. As for the other items of the analysis, no significant differences were observed either in relation to inter-analystor inter-date factors, and thus resproducibility was considered good.
5) As for the Ricketts itsems of analysis, a number of Omeasuringpoints were found to show significant differences between one analyst and another, but no variation resulting from the differences in dental age was observed. The authors have thus concluded that the Ricketts method of analysis is sufficiently effective to be applied also to children in the primary dentition period.

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This research was initiated to answer the question of whether Ricketts Analysis could be applied to the primary dentition of Japanese children.221 subjects with normal occlusion were followed longitudinally with lateral cephalograms from the ages of 3 to 10. Each one of the coefficients of regression was used to obtain the annual growth, then, mean values, standard deviations and annual growth rates were calculated to compare children in their primary dentition period (3 to 5 years old) to those in their mixed denture period (6 to 10 years old).
The findings were as follows:
1) For the tooth measurements, no major changes were observed in molar relation and canine relation from the primary dentition to those of the mixed dentition. Major differences were observed, however, between the deciduous teeth and permanent teeth for the measurements of the incisors.
2) Convexity and lower facial height, which show the relationship between the upper and lower jaws, were almost the same in both the primary dentition and in the mixed dentition.
3) Concerning the relation between the cranial base and the face. Point A showed a lower degree of forward movement than that of Nasion duringe the period starting in the primary dentition and continuing up to the mixed dentition period. Pogonion was found to exhibit a smaller degree of forward growth during and after the period of mixed dentition than that reported in the past.
4) With regard to internal structure, it was found that cranial deflection decreased while the mandibular are chowed no changes during the period of change from primary dentition to mixed dentition. These findings differ from what has been reported until now. In other items examined, however, a discrete degree of growth was observed during this period.
5) In applying the Ricketts Analysis to children in their primary dentition, there is a need to take into consideration mean values and standard deviation values in the clinical norms and clinical deviations for each age.

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The phenomenon of taste adeptation has studied extensively, but mostly subjective estimates of changes in magnitude of taste intensity with time have been employed. There appear to have been no previous studies of changes in salivary flow during taste adaptation. The study by Webb and McBurney measured the amount of whole saliva secreted when 2 ml of acid was put into the mouth, but they were not able to determine how the salivary flow rate changed during the one minute of acid stimulation. The objective of this study was to determine how the salivary flow rate changes during constant gustatory stimulation and whether the rate of change is dependent on the nature and intensity of the stimulus.<We measured changes in the flow rate of parotid saliva from 12 subjects while a tastant was infused continuously into their mouths. The tastants employed were sucrose, sodium chloride, and citric acid, each at two different concentrations. The rate of the parotid saliva, collected with a Lashley cannula, was monitored continuously by allowing the saliva to flow into a beaker on an electronic balance connected to an integrator and chart recorder. A four-way valve system was devised so that water and then a tastant solution at 34°C could be infuscd into the mouth and then exited into a kidney bowl.<All of the subjects showed adaptation of the salivary flow rate in response to the constant gustatory stimulation. Comparison of the maximum flow rates achieved with the higher and lower concentrations of each of the three stimuli showed that higher concentrations elicited significantly higher flow rates for all three types of stimulus (p<0.01). Analysis of variance revealed that none of the half-times (the time for the rate to decrease by half) for the six different tastants was significantly different from the others. The mean half-time for flow rate adaptation after the maximum flow rate had been achievcd was 11.4±5.8(S. D. )second. The mean value of the time between initiation of stimulation and achievement of thc maximum flow ratc was 6.4±3.1 second. Thus the flow rate increases to a maximum in about 6 second and then begins to fall exponentially with a halftime of about 11 second, even though gustatory stimulation is maintained constant.

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The rate that substances diffuse out of dental plaque will influence clearance of acid from the plaque into the saliva. In studies of the salivary clearance of sugar or fluoride, it has been found that this occurs at different rates in different locations in the mouth and that retention of substances at various sites is related to the salivary flow rate. The aim of this study was to compare the rates of clearance of potassium chloride from artificial plaque positioned bilaterally at different locations in the mouth.
The diffusant was 1 mol/L in a 1.0% agarose matrix, placed in wells 1.5 mm deep, in small acrylic devices 3 mm thick, which could be fastened to the teeth with dental floss. The diffusion chambers were taken from the fluid at selected time intervals and the gels transferred quantitively to flasks containing 40 ml of 100 ppm sodium chloride. The fluid was agitated intermittently for one and one-half hours, and then analyzed for pottassium with flame photometer.
For 10 subjects (6 years of age), half-times (the time for the initial pottassium concentration to decrease by half) for the lower anterior lingual regions averaged about 1.4 times greater than those for clearance into a large, stirred volume in vivo, whereas those for the upper anterior labial regions were about 5.7 times greater. When salivary flow was stimulate by sucking sour lemon drops, all halftimes were reduced from 40% to 70%. The half-times varied markedly in different regions of the mouth and this may be due to the buccal sites being exposed only to minor rather than major salivary gland secretions.

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The prevalence of juvenile periodontitis was examined in 3603 high school students by using a three-stage diagnostic procedure. The subjects were screened initially by assessment of the mobility of the upper central incisors. The number of positive subjects came to 38 males and 22 females, followed by assessment of probing depths of the pockets around the central incisors and first molars. The number of positive subjects with more than 4 mm of pocket depths came to 7males and 4 females. Subsequently, a full clinical and radiographic examination was performed on 5 of them, and one female subject was diagnosed as incipient juvenile periodontitis (0.03% of the total subjects).
The patient enjoyed good general health. Radiographic examination showed vertical bone loss around central incisors and left first molars. Subgingival plaques were taken from the patients under the anaerobic conditions, and the subgingival flora was composed of 51 % obligative anaerobic,17% facultative anaerobic,32 % unknown bacteria, respectively. Predominant bacteria were Fusobacterium and black-pigmented Bacteroides. Actinobacillus actinomycetemcomitans was also isolated. After treatment with subgingival scaling and root planing for 6 months, the predominant bacteria in the subgingival flora was found to shift from Gram negative rods to Gram positive rod Actinomyces, which are usually associated with from healthy subjects.

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The purpose of this study was to investigate the influence of etching times on the effect of acid etching on the primary ground enamel.
Forty labial surfaces of the extracted or exfoliated caries-free primary anterior teeth were used. The outer, middle and inner enamel layers were prepared without water colling with a carbite bur from the distal to the mesial direction on the same labial surfaces of the teeth. Each layer was divided into incisal, central and cervical areas, so that, nine sections were obtained on the same labial enamel surfaces.
Etchant used in this study was 40% phospholic acid gel and the etching times were 10,20,30 and 60 seconds. All specimens were washed with an air water spray for 30 seconds after etching. The following observations were obtained using the SEM.
1. Prism structures were observed in 359 sections (99.7 %) in 360 sections of 40 etched primary teeth.
2. The most common etching pattern was peripheral etching pattern for all layers, areas and etching times. Peripheral etching pattern was observed in 356 sections (98.9%) out of 360 sections.
3. The rate of the cases which showed poorly structured etching pattern was higher with etching times of 30 and 60 seconds than with 10 and 20 seconds of etching times.
4. Over-etching view was observed in cases etched for 60 seconds and especially such an inclination was observed with the inner enamel layers.
5. Thirty seconds is a sufficient time for etching on the ground primary enamel.

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Recessive dystrophic epidermolysis bullosa is a heritable disorder of the skin and mucous membrane, characterized by severe skin blistering after minor trauma. Due to the recurrent blistering, such symptoms as scars, flexural contractures and mitten-like deformities of the hands and feet will be observed as result.
The origin of recessive dystrophic epidermolysis bullosa is unknown. We have studied in this paper a sister (13y.6m. ) and brother (10y.8m. ) with this syndrome, relating to dental probles.
The findings were as follows:
1. Severe dental caries were observed in all of the deciduous and permanent teeth.
2. Oral examination and dental films revealed no congenital defects in the developing tooth buds.
3. The shapes, numbers, eruption and development of the permanent teeth were within normal limits.
4. Although mild enamel hypoplasia could be observed in the patients, there were no pitted teeth characterized by this disease.
5. Microstomias were obviously found, so that it was very difficult to perform dental treatment.
6. The buccal and labial vestibules and palatal rugae were obliterated by tissue scars.
7. As far as the oral mucosa, labia oris and tongue are concerned, there was recognized a large number of bulla, inflamation and cicatrization.
8. Since the treatment, they have shown a better and healthy appetite. Their foul breath has also disappeared after the oral hygienes was improved.

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For thirty nine children having chronic thumb sucking, the preveptive medicine for thumb sucking in the form of a type of manicure was applied to the nails of these children. The duration of time for this experiment was one month.
The results were as follows:
1) Twenty two children stopped the habit of thumb sucking, thirteen decreased the frequency of thumb sucking, and four continued the habit.
2) In three to ten days thumb sucking recured in the case of four children out of the twenty two whose thumb sucking had been eliminated by the medicine.
3) Thumb sucking was eliminated in less than one day in the case of five children, less than three days in the case of six, and more than one week in the case of five.
4) The rate of the elimination of thumb sucking was 47.0% at the age of four,38.0% at the age of five and 83.3% at the age of more than six. And as the children become older, this medicine is more effective.

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A number of the bizarre and unusual anormalies in human teeth becomes evident during the childhood years. While teeth usually erupt synmetrically at certain times, it is often found that in spite of the eruption of a tooth on one side. The tooth on the other side does not erupt and moreover is found to be transposited or rotated. If teeth are not erupted or delayed in erupting. They become an obstacle not only with respect to occlusal function but also esthetically. In the case examined it was found by X-ray examination that the mandibular second molar inclined mesially during the eruption period, and absorbed the distal root at the center of cervical area of the mandibular first molar. On the other hand, the mandibular left second molar was about to erupt, and it appeared normal. There was nothing peculiar about the growth of the patient, and the cause of uneruption of the tooth was not clear. It is suggested that a recall examination must be carried out till the second molars perfectly erupt.

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