JOURNAL OF DENTAL HEALTH
Online ISSN : 2189-7379
Print ISSN : 0023-2831
ISSN-L : 0023-2831
Volume 12, Issue 2
Displaying 1-4 of 4 articles from this issue
  • III. Effect of stannous fluoride on the acid solubility of powdered enamel (2nd report)
    Shoogoro OKADA, Moriyo HINOIDE, Hiromasa AKADA
    1962 Volume 12 Issue 2 Pages 75-81
    Published: 1962
    Released on J-STAGE: March 02, 2010
    JOURNAL FREE ACCESS
    The procedure for determining the solubility of powdered enamel was as follows: Using the mechanical shaker, 100 mg of 100-150 mesh enamel powder was treated with 10 ml of 2% NaF or 1, 2, 4, 8 and 16% SnF2 solution for 5 minutes at 20°C respectively, and in addition, the samples treated similarly four times in repetition were also prepared. Control groups were treated with distilled water in place of fluorides. The sample was decalcified with 10 ml of N/5 acetate buffer (pH 4.0) for 20 minutes at 37°C. The decalcification was repeated ten times, and in each run, amount of calcium and phosphorus dissolved from samples were determined with EDTA-titration method and Phospho-Vanado-Molybdate method respectively.
    The effectiveness of these fluorides on reducing the acid solubility of powdered enamel was estimated by the sum of calcium and phosphorus values in each decalcification run together with the cumulative value of them.
    Following conclusion were obtained.
    1. The lower acid solubility was found in groups treated with fluorides than in control groups.
    2. In earlier decalcifing stage, the effects of reducing acid solubility were indicated superior in samples treated with 1% or 2% SnF2 solution to that treated with 2% NaF, 8% or 16% SnF2 solution.
    3. Four times repeated treatment with either NaF or SnF2 were more effective than single treatment in reducing the solubility. Among SnF2groups, the differences of total dissolved calcium and phosphorus amount between single and four times treated samples were more marked in 1% or 2% groups than in 8% or 16% groups.
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  • Part 1: On the Decay of the Deciduous Teethand the Body Weight
    Tetsuro TSUBONE
    1962 Volume 12 Issue 2 Pages 82-91
    Published: 1962
    Released on J-STAGE: November 26, 2010
    JOURNAL FREE ACCESS
    When medical examination of small infants and premature infants in Tokyo City were made, clinical tests on teeth were also made at the same time. When premature infants, that is, infants whose number of months within the womb was less than nine and a half months, and the weight of the body at the time of birth less than 2500 grams, were picked out from the results obtained on the above mentioned occasion, it was found that there were the following number of premature infants, and number of teeth.
    Male infants 162 Number of teeth 2056
    Female infants 209 Number of teeth 2664
    Total number of infants 371 Total number of teeth 4720
    Precise study was conducted on these infants.
    For male and female infants below 2 years of age, an inspection was held every two months, infants two years of age, every six months, infants above three years of age, once every year.
    The infants weighing between 2301 and 2500 grams at birth were put into “heavy (A) class” and infants weighing 2300 grams or less put into the “ light (B) class ”.
    Next, the def condition, that is, the percentage of decayed experienced infants, the average number of decayed teeth per person and percentage of decayed experienced teeth were obtained.
    The results were compared with those reported by MISU (1960) concerning the def condition of ordinary infants. Furthermore, the present body weight was divided into three groups, namely, “ heavy ”, “medium ”, and “ light ”, in accordance with the limit of M±1/2σ given by the body growth value reported by FUNAKAWA (1961).
    After that, the relation between the def condition and growth type of those belonging to the groups of “ A to A ”, “ B to A ”, “ A to B ”, and “B to B” were studied.
    When the def condition was observed according to the age and type of teeth, the following results were obtained.
    1. As for the def for ordinary infants compared with the infants according to the weight of the body the time of birth, the premature infants show a higher of decay than the ordinary infants. As for the “ A ” group and the “ B ” group of the premature infants, both exhibit rather similar tendency.
    2. As for the def condition according to the type of growth, under two years of age, all show similar values. However, for infants two years of age or above, “A to B” groups show the highest rate followed by “B to B” groups. The “A to A” and “B to A” groups show rather similar tendency. This is shown in the case of average number of decayed teeth per person and percentage of decayed experienced teeth.
    3. As for the def condition according to the types of teeth, the deciduous upper central incisor and upper lateral incisor teeth show a high rate in the order of “A to B”, “B to B”, “A to A”, “B to A” groups. As for the deciduous canine teeth, a similar tendency could be observed for all groups, up to the age of three years. As for the 1st and 2nd deciduous molar teeth, both the upper and lower teeth show decay earlier for the “A to B”, and “B to B” groups than for any other groups. This tendency grows with the increase in age.
    4. From the above mentioned facts, the writer firmly believes that for the dental measures concerning the premature infants, special attention should be placed on the infants which show a retarded growth rather than the actual body weight at the time of birth.
    Especially for a two years old infant, care should be exerted towards the upper deciduous central, and uppers deciduous lateral incisor teeth, For a three year old infant, special attention should be placed on the 1st and 2nd deciduous molar teeth.
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  • Teruo NIWA, Hiroshi HAYAKAWA, Akira NAGAI, Sigeo KIKUCHI, Satosi TAGUC ...
    1962 Volume 12 Issue 2 Pages 92-97
    Published: 1962
    Released on J-STAGE: March 02, 2010
    JOURNAL FREE ACCESS
    Within the period of twelve years from 1948 to 1959, mass dental examination was performed on a total of 14, 194 infants residing in the Ward District of Tokyo City. When the conditions for successive years were observed, the following results were obtained.
    The caries of deciduous teeth were expressed by the total of def., in other words, the total of caries of deciduous teeth, teeth requiring extraction and filled teeth.
    1. When the percentage of persons who have experienced def and the average number of def teeth per person are observed in accordance with age and year, the figures for each age group are extremely small in the year 1948.
    Furthermore, there is a tendency of the percentage of the caries of teeth increasing for each age group with every passing year.
    This tendency is greater for the average number of def per person than for the percentage of the persons who have experienced def
    2. When the totals of the figures for the percentage of persons who have experienced def and the average number of def per person are taken for each age group on an annual basis, and the average of the respective years is taken, although there are a few exceptions, the following tendency can be observed.
    As for the percentage of persons who have experienced def in 1948 the percentage was in the thirties, from 1949 to 1959 in the fifties, especially in the period from 1958 to 1959 the percentage was an extremely high value of almost 60.
    As for the average number of def per person, in 1948, between 1 and 2, in 1949 between 2 and 3, in the period from 1950 to 1953 between 3 and 4, in the period from 1954 to 1957 between 4 and 5, in 1958 and 1959 between 5 and 6, and all showed a tendency of increase with every passing year.
    3. Next, the average number of def per person of the annual def which showed a tendency of extreme increase weee taken and observed from the age group point of view.
    The results were as follows:
    Each age group showed a tremendous rise in the period from 1948 to 1949, and infants from 2 years to 5 years of are showed a tendency of the average number of def increasing with age. However, those who belong to the 1 year old age group show a decreasing tendency with every passing year.
    Those belonging to the three-year-old age group began to show a tremendous increase recently, that is, from around 1957.
    4. When we compared on the annual basis the average number of def per person for infants belonging to the one-year-old age group and the types of nutrition taken by the infants residing in the Ward District of Tokyo (based on the investigation made by the Tokyo City Authorities) we found that there was an inverse correlation between the average number of d. e. f. per person and the rate of the bottle fed infants and children.
    5. As for the average number of def per person, recently, we conducted the following investigation on the infants belonging to the three-year-old age group which showed a gradual increase in the number of def per person.
    The def were divided into five layers from a morphological point of view and observed. It was found that there was an increase in def in all layers.
    6. From the above observations, the annual changes in the def of infants and children residing in Tokyo City, and a few points associated with them were made clear.
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  • S. Okubo, K. Itakura, H. Sassa, K. Goshi, K. Yarita, K. Takashina
    1962 Volume 12 Issue 2 Pages 98-102
    Published: 1962
    Released on J-STAGE: March 02, 2010
    JOURNAL FREE ACCESS
    The authors, applying GSR (Galvanic Skin Reflex), made experiments on the changes in mental process caused when vibrations of various cycles are given to teeth. Subjects of the experiments included 15 persons who had sound teeth and surrounding tissues GSR was measured with the use of Takei's Polypsychograph. The following results have been obtained in the above experiments.
    1) When mental influences caused by unpleasant vibrations were tested through GSR, it was found that vibration of certain frequency was the main cause of disagreeable feeling to the subjects given direct vibration to their teeth just as they feel unpleasant by some sound to their ears.
    2) Vibrations of about 700 cycles caused the largest reflex, then those of about 300 and 1, 000 cycles caused next largest reflexes. It was also found that 300 cycles and those in the vicinity of integral multiples of the cycles, the specific frequency of teeth pointed out by Sasaki Group, showed remarkable GSR when direct vibration was given to teeth.
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