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At least 19 recordsLinked to original sources

Congenital hypothyroidism and changes in the enamel of deciduous teeth.

Deciduous teeth from children with congenital hypothyroidism were collected and ground sections were prepared. The sections were analysed by means of polarized light and microradiography. The enamel in ground sections of deciduous teeth from children with congenital hypothyroidism showed an increase in areas with elevated pore volume distribution in both the pre- and postnatal enamel. The findings suggest that thyroid hormone influences enamel maturation. Further, alterations in enamel structure, presumably due to prenatal thyroid deficiency, were found to be more common among children with neurological abnormalities at the age of 7 to 9 years.

Child, Preschool↗

[Comparison between children with missing anterior deciduous teeth and posterior deciduous teeth by analysis of speech sounds].

Growing human offsprings are creatures that communicate by language. If rapidly growing children lose their deciduous teeth very early in life, their language and pronunciation functions may be seriously affected. The authors conducted a series of tests to find how the voice changes when deciduous teeth are extracted. The results may be summarized as follows. 1. There was no significant difference in the formants of vowels on "a-gyo", the first line of the Japanese syllabary, but an appreciable difference was recognized between children (four to six years old) with missing anterior teeth and posterior teeth when there were consonants before and after these vowels. 2. In the formants of the vowels, there was a marked difference in the vowel "i" when children were fitted with no appliance. 3. The strength of voice components in each frequency range was compared between children with missing anterior teeth and posterior teeth. It differed widely in "o ka a sa n" (which means "Mother") and "a-gyo", when children were fitted with no appliance. These findings indicate that the pronunciation of "o ka a sa n" and "a-gyo" can be recovered to some extent if the children are provided with an appliance. However, a sound analysis indicates that their pronunciation ability of sounds on "ka-gyo", "sa-gyo" and "ta-gyo" (the second, third and fourth lines of the Japanese syllabary) can hardly be fully recovered.

Child↗

Environmental and physiological factors affecting lead and cadmium levels in deciduous teeth.

Shed deciduous teeth lead and cadmium content of children from Cartagena (Spain) was assessed. Parents were provided with an interview containing different questions concerning family socioeconomic status, child's health history, zone of residence, or home antiquity. Besides, physiological variables were considered, i.e., sex of donor, presence of caries, type of tooth donated, tooth weight, age of shedding, and position within the mouth. Tooth lead and cadmium data showed a positively skewed distribution and were log-normalized for further analyses. No statistically significant differences could be observed for lead and cadmium values according to the sex of donor. Both heavy metals decreased in content from incisors to molars and with age of shedding. The one-way analysis of variance (ANOVA) displayed both environmental and physiological risk factors contributing to high tooth lead and cadmium values. When a multifactor ANOVA was carried out, the associations between home antiquity, nail biting habit, and jaw with tooth lead levels, as well as those between zone of residence and tooth cadmium levels were found to persist. However, the only common factor for both heavy metals in the multiple analyses was the type of tooth.

Cadmium↗

[A study of trace elements in deciduous teeth. The differences of Cd, Zn, Pb, and levels in prenatally and postnatally formed deciduous teeth].

It has been reported by some investigators that deciduous teeth could be useful materials for the analysis of the trace elements available to the human body burden. In this study, an attempt was made to define that uptake of trace elements (Cd, Zn, Pb and Cu) take place during formation of the deciduous tooth. Samples were prepared from exfoliated human upper deciduous central incisors divided into two or three sections at incremental lines includes neonatal line. Samples were dissolved with nitric acid and dried at 80 degrees C. Each element was separated chromatographically using acetone-HCl gradient solution with a cation exchange resin and then analyzed by flameless atomic absorption spectrophotometry. The results were as follows: 1. Ca, P, Ca/P ratio levels showed no significant differences between prenatally and postnatally formed teeth. 2. In the enamel, (1) Cd level showed a tendency to be higher in the postnatally formed enamel, but not significant. (2) Zn and Pb levels were found to be significantly higher in the postnatally formed than in the prenatally formed enamel. (3) Cu level was reversed significantly. 3. In the dentin, (1) Cd and Cu levels in the postnatally formed dentin I were significantly less than prenatally formed denin, and these were almost equal to the postnatally formed dentin II. (2) Zn level in the postnatally formed dentin I was almost equal to the prenatally formed dentin, but that was significantly less than the postnatally formed dentin II. (3) Pb level in the postnatally formed dentin I was significantly less than the prenatally formed dentin and the postnatally formed dentin II. Therefore, the results suggest that the accumulation of Cd and Cu to the deciduous tooth mainly occur in the prenatal and the accumulation of Zn and Pb to the deciduous tooth occur not only in the prenatal but also continuously in the postnatal, and the deciduous tooth can be a useful materials for environmental contamination recorder.

Cadmium↗

Ultrastructural study of the root dentine surface resuming resorption on human deciduous teeth.

Resorption of deciduous teeth is not continuous, but alternates with periods of repair or rest. Dentine surfaces in periods of rest or repair resume resorption by odontoclasts during physiological root resorption of the deciduous teeth. However, no observations of such dentine surfaces have been shown. The characteristic feature of the dentine surfaces resuming resorption remains unknown. Tartrate-resistant acid phosphatase activity (TRAP) was detected on human deciduous teeth. The root resorbing surfaces on these teeth were photographed with a whole-mount light microscope, and the photographed areas were serially sectioned into 0.5 micron semithin sections. Preodontoclasts and odontoclasts were three-dimensionally reconstructed. On root resorbing surfaces, areas with small scattered TRAP-positive cells were observed among areas with many TRAP-positive resorbing odontoclasts and TRAP-negative areas. The sections showed that areas with small scattered TRAP-positive cells have features similar to those of TRAP-negative areas, but there were three kinds of characteristic TRAP-positive cells: preodontoclasts, odontoclasts forming small lacunae, and preodontoclasts, and odontoclasts with cytoplasmic processes extending to the dentine surface, which is covered with cells. These results suggest that the areas with small scattered TRAP-positive cells could be at the stage of resuming resorption, and show that the presence of preodontoclasts and odontoclasts with cytoplasmic processes extending to the covered dentine surface is a characteristic feature of the dentine surface at this stage.

Acid Phosphatase↗