Kazuko Igari

Acoustic Diagnosis Device for Dentistry

There are a lot of diseases which show the abnormal elastic property. Although many medical doctors and dentists have noticed the change of tissue elasticity due to the disease, the diagnostic device to examine the tissue elastic property objectively has not well developed.

ANALYSIS OF TRACE ELEMENTS IN PRE- AND POST-NATAL TOOTH ENAMEL USING MICRO-PIXE

Naturally shed deciduous teeth are potentially useful as a biomarker of environmental exposure. To assess the prenatal environment of child, we tried to present the neonatal line on the elemental maps and investigate the trace elements in pre- and post-natally formed tooth enamel using micro-PIXE. Generally, the neonatal line is observed more clearly in the tooth from child who has some difficulties at birth. In this study, five deciduous teeth from five children with developmental disorders were used for analysis. Seven trace elements (Na, Mg, Si, Cl, Fe, Zn, and Sr) were detected in enamel of all five teeth. The line, it was thought neonatal line, was observed on the elemental map of Ca and P in the tooth from the child with serious birth complications. In order to compare the elemental concentration between pre- and post-natal enamel, concentration variation of elements were projected along the line perpendicular to the neonatal line. Lower Ca concentration in prenatal enamel was observed. By tracing the location of neonatal line on the other elemental maps, the concentrations of detected trace elements were compared in the same way. The differences of concentration of these trace elements between pre- and post-natal enamel were not clear because of much statistic variation. We could determine the trace elemental profiles and concentrations around the neonatal line in the enamel from the child with serious birth complications.

APPLICATION OF MICRO-PIXE ANALYSIS TO INVESTIGATE TRACE ELEMENTS IN DECIDUOUS TEETH ENAMEL

The early life environment has widespread consequences for later health and disease. To prevent the disease in later life, the assessment of fetal environment is very important. In Japan, birthweight has fallen rapidly during recent two decades. The reduction of birthweight represents reduced fetal nutrition. Deciduous tooth enamel contains pre- and postnatal enamel and its chemical composition reflects the status of metabolism of trace elements during formation period. Deciduous tooth enamel is considered to be a suitable indicator of trace elements exposure in utero. We applied micro-PIXE analysis to investigate the trace elemental content in deciduous tooth enamel. Two deciduous canines from one healthy Japanese boy were used for this study. The enamel section including pre-and postnatal enamel was prepared for micro-PIXE analysis. Five trace elements (Na, Mg, Cl, Zn, and Sr) were detected in the scanning area of tooth. The distribution profiles of 5 elements were obtained as X-ray maps. The distribution profiles of zinc and chlorine were specific, and showed higher concentration in surface enamel. No elements showed different profiles of X-ray maps between pre-and postnatal enamel in this sample. The results of this study suggested that micro-PIXE analysis would be able to estimate the trace elements in prenatal and postnatal enamel, respectively.

Caries experience in nursery school children in Sendai, Japan: Time trends from 1972–2002

Abstract Since 1972, we have been conducting an annual clinical dental examination for young children at 13 nursery schools in the north district in Sendai, Japan. In the present study, we have included the results of examinations conducted in 1997 and 2002, and analyzed the time trends in caries experience of the primary dentition over a 30-year period from 1972 to 2002. The caries experience in the primary dentition markedly decreased in 1977 and remained stable for about 15 years, but in 1997, it markedly decreased again and continued to decrease in a linear fashion until 2002. The time trends in caries experience in the primary dentition in each age group were further analyzed by ascertaining caries experience in each tooth type. The results showed that, in 2 to 4-year-old, the decrease of caries experience for the primary maxillary incisors, canines and first molars seemed to stop decreasing in 2002, but for the 5-year-old, the caries experience for the maxillary incisors and canines and the maxillary and mandibular first and second molars markedly decreased from 1997 to 2002.