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Volume 43 (1993)
- Issue 5 Pages 636-
- Issue 3 Pages 254-
- Issue 2 Pages 144-
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Volume 43, Issue 5
Displaying 1-10 of 10 articles from this issue
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Satoshi TADA1993 Volume 43 Issue 5 Pages 636-650
Published: October 30, 1993
Released on J-STAGE: October 27, 2010
JOURNAL FREE ACCESSMercury levels in scalp hair of 112 male and 20 female dentists and 134 female dental hygienists and assistents were determined by cold-vapor atomic absorption spectrometry to evaluate the mercury absorption as a result of their dental practice and to provide updated data concerning mercury levels of dental practitioners. The control group was made up of 246 persons (110 males and 136 females), all of whom had never been occupationally exposed to mercury.
When a hair sample was collected, a questionnaire was also filled out. The questionnaire items included name, address, sex, age, occupation, frequency of seafood consumption, and, in the case of dental personnel, the number of amalgam fillings administered per week, method of amalgam condensation, years in dental practice, and so on.
The results were as follows:
1) The hair mercury levels of Japanese dental personnel did not manifest any differences with those of the control group in either sex. In 1973, Miyazawa found a significant difference in mean levels between dentists and a control group. However, the present study suggests that the exposure of dental personnel to mercury has decreased to non-occupational levels. For male and female dentists and dental hygienists and assistants, the geometric means were 4.30ppm, 2.37ppm and 1.90ppm, respectively. The geometric means of the control group were 3.85ppm (males) and 2.12ppm (females).
2) The hair mercury levels of all the groups studied (male and female dentists, dental hygienists and assistants, male and female controls) demonstrated a positively skewed distribution and had a logarithmic normal distribution.
3) With respect to the dentists and the control, a statistically significant difference between the sexes was observed.
4) Significant correlations between hair mercury concentrations and age were found in the male dentists (p<0.05), the male controls (p<0.01) and the female dental hygienists and assistants (p<0.01); no correlation was found in the female dentists or the female controls.
5) No significant correlation between hair mercury concentrations of dentists and number of amalgam fillings administered per week was found.
6) Significant differences of hair mercury levels between high and low frequency seafood intake groups were found in both sexes (p<0.05).
7) Of 50 married couples studied, a significant correlation of hair mercury levels between husband and wife was observed (r=0.39, p<0.01).View full abstractDownload PDF (2563K) -
Hisahide HIGUCHI, Takeshi KONDO, Takashi NAKANE, Kaoru KASAHARA, Shige ...1993 Volume 43 Issue 5 Pages 651-658
Published: October 30, 1993
Released on J-STAGE: October 27, 2010
JOURNAL FREE ACCESSOne often sees cases of black and brown pigmentation on all enamel surfaces in schoolchildren with severe dental fluorosis. This pigmentation gradually disappears by attrition 4-5 years after eruption of the teeth. The reason seems to be decreasing hardness of the enamel. But this pigmentation is not seen all cases of fluorosis. Therefore, we tried to find the relationship between fluoride dose and incidence of pigmentation in the enamel of rats given 3.75-15.00mgF/kg/day in the form of NaF for 10 weeks.
We obtained the following results:
1. Body weight and food intake decreased in group 3 given 15.00mgF/kg/day, but water intake in all experimental groups increased by dose.
2. There was no difference between control and experimental groups in number of erythrocytes, or in hemoglobin and hematocrit values, but leucocytes decreased in all experimental groups.
3. Activity of cholinesterase (Ch-E), creatin kinase (CPK) and triiodethyronine (T3) decreased by dose, but we could not find any reason for the decrease in activity of CPK and T3.
4. Whiteness was found in all incisors of the experimental groups and bands of black and brown pigmentation were especially found in the maxillary incisors of rats given 7.50-15.00mgF/kg/day.
5. Hardness of enamel and dentin of both jaw decreased by dose. The mandibular incisors were harder than the maxillary incisors. But attrition of the mandibular incisors was severer than that of rhe maxillary incisors irrespective of hardness.View full abstractDownload PDF (1664K) -
1. Effect of Coenzyme Q10 on Subgingival MicroorganismsJudson T. MCREE, Takashi HANIOKA, Satoshi SHIZUKUISHI, Karl FOLKERS1993 Volume 43 Issue 5 Pages 659-666
Published: October 30, 1993
Released on J-STAGE: November 26, 2010
JOURNAL FREE ACCESS -
2. Effect of Coenzyme Q10 on the Immune SystemTakashi HANIOKA, Judson T. MCREE, Li-Jun Xia, Satoshi SHIZUKUISHI, Kar ...1993 Volume 43 Issue 5 Pages 667-672
Published: October 30, 1993
Released on J-STAGE: August 10, 2011
JOURNAL FREE ACCESS -
Akiko CHIGIRA, Yoshiharu MUKAI, Yoshihiro KANEKO1993 Volume 43 Issue 5 Pages 673-680
Published: October 30, 1993
Released on J-STAGE: October 27, 2010
JOURNAL FREE ACCESSIn considering oral health in early childhood, the importance of the environment in which children are raised is well recognized, in particular the feeding environment. Nevertheless, there is a scarcity of data concerning this area from the dental point of view.
The aim of this study was to investigate the eating patterns in young children and discuss the necessity of feeding guidance. The subjects were 434 children, three years of age, and their parents who visited the Tama Public Health Center in Tokyo for dental consultation. The child underwent a dental examination, and the parent filled out a questionnaire. Among the results from the dental examination, we focused on the number of decayed and filled primary teeth (df teeth) and occlusal conditions. Among the items in the questionnaire, we focused on the bedtime, the daily intake of milk, the use of a nursing bottle and the conditions of weaning from breast or bottle feeding. The factors effecting eating patterns were analyzed by x2 test and Hayashi's Quantification Theory II
The results were as follows:
1) There was no significant relation between eating patterns and bedtime, or daily intake of milk.
2) There was no significant relation between eating patterns and the use of a nursing bottle, and the conditions of weaning from breast or bottle feeding.
3) There was no significant relation between eating patterns and the number of df teeth. But the statistically significant relations were found between eating patterns and occlusal conditions, especially anterior crossbite (p<0.01) and the open bite (p<0.01).
4) In conclusion, the factors effecting eating patterns were intra-oral conditions (occlusal conditions) rather than bottle or breast feeding, or the environment in which the child was raised.View full abstractDownload PDF (1602K) -
Tamie OHASHI, Tokuko KANI, Mizuo KANI1993 Volume 43 Issue 5 Pages 681-688
Published: October 30, 1993
Released on J-STAGE: October 27, 2010
JOURNAL FREE ACCESSThe purpose of this study was to examine the effect of sodium fluoride in combination with pyridoxine hydrochloride solution on artificial caries lesion formation. Human enamel blocks were immersed and stirred in three kinds of solution at 37°C for 1 hour. The three solutions were as follows: (1) sodium fluoride in combination with pyridoxine hydrochloride solution, 900ppm of fluoride (F-), pH 4.5-NaF+VB6 group; (2) hydrochloric acid-acidified sodium fluoride solution, 900ppm of fluoride (F-), pH 4.5-NaF group; and (3) de-ionized water-control group. Artificial caries lesions were formed with demineralizing solution according to Moreno (1974), consisting of 50% hydroxyapatite saturated lactate buffer (pH4.5). Morphological examinations and microbeam X-ray diffractometry were performed.
In SEM preparations, a large amonut of spherical crystals were deposited on the enamel surface after fluoride treatment. In the NaF+VB6 group, these deposits were thicker and the crystals were larger than in the NaF group. No crystals were found in the control group. Calcium fluoride was detected on microbeam X-ray diffraction patterns of fluoride-treated enamel surface. The intensity of the X-ray diffraction pattern of calcium fluoride was highest in the NaF+VB6 group.
After lesion formation, granular or needle-like deposits were observed on the lesion surface in the NaF+VB6 group. This surface was smoother than in the control group, and demineralized surfaces were observed in the NaF group. The caries lesions of the control and NaF groups showed clear subsurface demineralization in contact microradiograms and polarized light microscopy. In the NaF+VB6 group, the lesions were unclear and thinner than in the other two groups. The depth of caries lesions was about 33 μm in the NaF+VB6 group, and about 100μm in the NaF and control groups. This depth was estimated by doing an EPMA analysis of SEM photographs of cross sections of the lesions. The microbeam X-ray diffraction pattern of the caries lesions showed hydroxyapatite in all groups. In the fluoride groups, the crystallinity of the lesions was higher than in the control group, and was the same as that of sound enamel.
These findings suggest that enamel immersed in sodium fluoride in combination with pyridoxine hydrochroride solution could be protected from artificial caries lesion formation.View full abstractDownload PDF (2524K) -
Mizuo KANI, Tamie OHASHI, Atsunori ISOZAKI, Tokuko KANI1993 Volume 43 Issue 5 Pages 689-698
Published: October 30, 1993
Released on J-STAGE: October 27, 2010
JOURNAL FREE ACCESSA cariostatic effect of soduim fluoride in combination with pyridoxine hydrochloride solution on artificial caries lesion formation was reported previously. The purpose of the present study was to examine the mode of action of this solution on enamel. Intact human enamel was immersed and stirred in three kinds of solution at 37°C for 1 hour. The three solutions were as followes: (1) sodium fluoride in combination with pyridoxine hydrochloride solution, 900ppm of fluoride (F-), pH 4.5-NaF +VB6 group; (2) hydrochloric acid-acidified sodium fluoride solution, 900ppm of fluoride (F-), pH 4.5-NaF group; and (3) de-ionized water-control group. Artificial caries lesions were formed with Moreno's demineralizing solution (1974), consisting of 50% hydroxyapatite in saturated lactate buffer (pH 4.5). Distribution of phosphorus, calcium, and fluoride in enamel were determined with line analysis by EPMA, and state analysis was performed to identify the reaction products in fluoride treated enamel.
The enamel surface contained 30-33% F in the NaF+VB6 group, and 14-15% F in the NaF group. Only Ca and F were detected in fluoride-treated superficial enamel by magnified analysis. Ca and F were also detected in the crystal deposits, and a large amount of calcium fluoride was seen in the NaF+VB6 group. The state analysis with EPMA showed that the reaction products were calcium fluoride and fluorapatite, and the volume of reaction products was very large in the NaF+VB6 group.
In EPMA analysis of caries lesions, the fluoride level was higher than in other sound enamel surfaces, and the NaF+VB6 group showed the highest level of fluoride. Calcium and phosphorus level in the NaF+VB6 group was the same as in the sound enamel layer, and the level was low in the NaF and control groups because of subsurface demineralization of the enamel. In state analysis with EPMA, fluorapatite was detected in the carie lesions, and the volume of fluorapatite was very high in the NaF+VB6 group.
In conclusion, soduim fluoride in combination with pyridoxine hydrochloride solution acted by producing calcium fluoride and fluorapatite on the enamel surface. Then calcium fluoride was released slowly into the demineralizing solution, and reacted with calcium and phosphorus in solution to produce fluorapatite. The greater formation of calcium fluoride in the NaF+VB6 group had a higher cariostatic effect than NaF solution alone.View full abstractDownload PDF (2716K) -
Changes in the Surface Structure of Demineralized Enamel Caused by Q-Switch Nd-YAG Laser IrradiationTadashi YOSHIKAWA, Daisuke INABA, Youichi IIJIMA, Okiuji TAKAGI1993 Volume 43 Issue 5 Pages 699-707
Published: October 30, 1993
Released on J-STAGE: October 27, 2010
JOURNAL FREE ACCESSChanges in the surface structure of demineralized enamel caused by Q-switch Nd-YAG laser were investigated with a scanning electron microscope (SEM). A total 44 demineralized enamel samples were used for this study. Samples were divided into 3 groups, (1) laser-irradiated with Q-switch Nd-YAG laser (wave length 0.53μm) at total energy density 25, 50, 75, 100J/cm2or 125J/cm2 after using India ink, (2) irradiated similarly to group (1) without using India ink, and (3) control without further treatment. After laser irradiation, the enamel samples were coated, and their surface structure was observed with an SEM.
The demineralized enamel was mainly of two types, that dissolved from the enamel sheaths (Type I) or that dissolved from the enamel rods (Type II).
Demineralized enamel of Type I was melted and linked by laser irradiation with using India ink at over 100J/cm2 of total energy density. Demineralized enamel of Type II acquired a rough surface when treated with laser irradiation at over 100J/cm2. On the other hand, demineralized enamel of Type II was still porous after laser irradiation without India ink.
The Changes in the surface structure of demineralized enamel caused by Q-switch Nd-YAG laser depended on the type of demineralization.View full abstractDownload PDF (3494K) -
Yoshihisa YAMASHITA, Shuji AWANO, Toshihiro ANSAI, Hideo MIYAZAKI, Tad ...1993 Volume 43 Issue 5 Pages 708-710
Published: October 30, 1993
Released on J-STAGE: October 27, 2010
JOURNAL FREE ACCESSDownload PDF (417K) -
1993 Volume 43 Issue 5 Pages e1
Published: 1993
Released on J-STAGE: October 27, 2010
JOURNAL FREE ACCESSDownload PDF (40K)
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