Toshiko Tanaka

Mn and Cu concentrations in mixed saliva of elementary school children in relation to sex, age, and dental caries.

To examine the standard Mn and Cu concentrations in mixed saliva from children and the relationship between these levels and dental caries, resting mixed saliva samples obtained from 527 children of an elementary school in Kitakyushu City were collected at 10:00-11:30 a.m. during December 2004. The Mn and Cu concentrations were determined using simultaneous multi-element atomic absorption spectrometry. The standard Mn and Cu levels were 22.0+/-15.2 and 3.8+/-4.1ng/mL, respectively, in the sound teeth group. Mn levels were significantly higher in boys (25.4+/-17.4ng/mL) than girls (19.1+/-12.3ng/mL) and also higher in upper (25.5+/-16.4ng/mL) than lower (19.0+/-13.5ng/mL) grades. The Cu level was unaffected by sex and age in the sound teeth group. The Cu level in children with caries experience (5.7+/-5.3ng/mL) was significantly higher than that of the sound teeth group. Moreover, the Cu levels in children with untreated caries were significantly higher than that of the sound teeth group, and increased with the number of untreated teeth. No significant difference was found in the Cu concentrations between the group in which all decayed teeth were treated and the sound teeth group. The Mn levels were similar with or without caries and treatment. These findings indicate that the Mn level in mixed saliva depended on sex and age, and suggest the possibility of Cu dissolving into mixed saliva by demineralization due to dental caries.

Al and Fe levels in mixed saliva of children related to elution behavior from teeth and restorations

OBJECTIVES The levels of trace elements in mixed saliva were not well-defined. This study was performed to determine Al and Fe concentrations in mixed saliva of children and to investigate the relationship between these levels and dental caries. METHODS Among 562 collected mixed saliva specimens, 514 and 548 samples for analyses of Al and Fe levels were obtained, respectively. The Al and Fe concentrations were determined using flameless atomic absorption spectrometry. RESULTS The Al and Fe concentrations in children without a history of caries were 0.093±0.136 and 0.121±0.128 μg/mL, respectively. The Fe level depended on sex. The Fe level in girls who experienced caries was significantly higher than that without caries history. The Al and Fe levels were significantly higher in children with treated caries than children without caries history. The Fe concentrations were affected by restoration type. Composite resin increased the Fe level significantly especially in girls, and the Fe level was also higher in boys treated with both composite resin and metal restorations. In children without caries history, the Al level was inversely proportional to the number of deciduous teeth and increased with the number of permanent teeth. In contrast, the Fe level showed the reverse tendency. CONCLUSIONS The Fe level in mixed saliva of children was influenced by the restoration type. It was suggested that Al was eluted more from sound permanent teeth than sound deciduous teeth, while Fe was eluted in the opposite manner.

Simplifying the Assessment of Stereognostic Ability of the Tongue inElderly Subjects Using Six Selected Test Pieces

This study aimed to develop a simple method to assess the stereognostic ability of the tongue in elderly. The stereognostic ability was assessed by placing 6 differently-shaped test pieces in the oral cavity and assessing the subjects’ ability to identify the shape using their tongues. These test pieces were selected from 20 test pieces that were previously used for detailed analysis of stereognostic ability of the tongue. Stereognostic ability of the tongue in elderly subjects was compared with young adults. In total, 188 out of 198 young adults (94.9% of subjects), 26 out of 60 elderly (43.3%) not receiving care, and 1 out of 18 elderly (5.5%) receiving care could identify all 6 test pieces correctly. The most misidentified piece was a rectangular test piece and it was recognized as the test piece of the same size without corners, and vice versa. When 35 elderly who were not receiving care were assessed using either 6 or 20 test pieces, the number of correct responses for the 6 test pieces showed a significant positive correlation with those for 20 test pieces (p<0.001). These results indicate that the method using just 6 test pieces is a simple yet effective approach to assess stereognostic ability of the tongue and that it could be used in future assessments with larger and more diverse patient populations.

Brain Activity during Stereognostic Discrimination Using the Tongue Measured By Functional Near-Infrared Spectroscopy

We previously reported our investigation of the stereognostic ability of the tongue to recognize the shape and size of materials in the mouth and its clinical applications. In the present study, we observed brain activity while performing stereognostic discrimination using the tongue; the changes in levels of oxyhemoglobin (oxy-Hb), deoxyhemoglobin (deoxy-Hb), and total hemoglobin (total-Hb) in the frontal cortex area of 37 healthy individuals (18–75 years old) were measured using a functional near-infrared spectrometer with 45 channels. As an experimental task, the stereognostic test piece (TP) was placed on the center of the tongue dorsum, and subjects moved the TP for shape discrimination without letting it touch the teeth or gums. As a control task, subjects did not move the TP placed on the tongue. Stereognostic task-attributed changes in Hb levels were obtained by subtracting the Hb level of the control task from that of the experimental task. During the stereognostic task, oxy-Hb levels increased in the frontal cortex, including the prefrontal area, in most subjects. However, the results also demonstrated large individual variability. When the degree of change in Hb levels during the stereognostic task was mapped, it was found that the changes in the oxy- and total-Hb levels were similar, while the deoxy-Hb level did not change to the same degree. When subjects were divided into three groups, highly-, moderately- and mildlyincreased oxy-Hb levels, there was a significant negative correlation between age and degree of oxy-Hb level increase. The present study suggests stereognosis may be involved in several different information processing pathways, and that aging may also be a factor in the large variability we observed.