Tokuko Kani

Determination of Titanium (IV) in Human Enamel

フッ化チタン化合物作用後のエナメル質中のチタン (IV) を原子吸光光度法を用いて定量する方法を確立する目的で, 原子吸光分光分析装置によるチタン (IV) の測定について基礎的検討を行った。原子吸光分光分析装置には日立偏光ゼーマン原子吸光分光光度計 (180-80形) を用い, 測定条件の設定, 共存元素, 無機酸による妨害, ランタンによる妨害除去, ならびに標準添加法による定量について検討を行った。1) 原子吸光光度法によるチタン定量の至適測定条件は, 波長364.3nm, ランプ電流値12.5mA, バーナー高さ10.20mm, アセチレン流量0.37kg/cm2, 亜酸化窒素流量1.60kg/cm2であった。2) エナメル質中に共存する元素すなわちカルシウム, リン酸, マグネシウム, フッ素による妨害, ならびに過塩素酸, 塩酸, 硫酸などの無機酸による妨害が認められた。3) リン酸による妨害はランタン添加により抑制が可能であったが他の元素の妨害除去はランタン添加では不可能であった。4) エナメル質試料の標準添加法による定量では, 測定値の再現性が低く, 実用性に欠けることが認められた。以上の結果から, エナメル質試料溶液中のチタン (IV) を直接定量することは妨害イオンが多く困難であリチタン (IV) を分離する前処理が必要であることが判明した。

Residual Fluorine in the Mouth Following the Use of a Fluoride Mouth Rine

The present study was made for the purpose of reinvestigating the safty of fluoride mouth rinse, the possibility of caries-preventive effect and the rinsing method itself by determining the amount of fluoride that remains in the mouth after the use of fluoride mouth rinse.A total 80 children in the third grade of primary school (consisting of 44 boys and 36 girls) were selected as subjects. They were instructed to rinse with 10ml of the fluoride mouthrinsing solution (containing 500ppm of F-; pH 5.0, phosphoric acid-acidified NaF solution) that had been exactly measured for 30 seconds, and then rinse the mouth twice with 10ml of distilled water for 10 seconds at a time. The fluorine content of the portion of the agent that remained in the rinsing cup, the amount of fluorine that was spit out after use of the rinse, and the fluorine content of the rinsing distilled water were determined. For the determinations, an ORION ion meter (model 801) and fluoride ion activity electrodes were used.As a result, the sum of fluorine content of the portion of the rinsing agent that remained in the rinsing cup and the amount of fluorine that was spit out was 4.69±0.12mg in the boys and 4.58±0.12mg in the girls, corresponding to 93.79% in the boys and 91.52% in the girls of the amount of fluorine that had been given.Using the conventional rinsing method, the amount of residual fluorine in the mouth was 0.31±0.12mg (6.21%) in the boys and 0.42±0.12 (8.48%) in the girls. When the use of fluoride mouth rinse was followed by a rinsing with water, the retention of fluorine was 0.16±0.12mg (3.13%) in the boys and 0.27±0.12mg (5.46%) in the girls. In 65 children, corresponding to 81.3% of the total 80 children, the retention of fluorine after use of the conventional fluoride mouth rinse was less than 0.5mg.From these findings, it was proved again that the fluoride concentration and volume of rinsing solution is entirely safe provided the rinsing method is adequate, and fluoride mouth rinse is an effective fluoride application method for the prevention of dental caries.