歯のフッ素濃度が異なる集団におけるう蝕の診断

Diagnosing dental caries in populations with different levels of dental fluorosis.

抄録

この研究の目的は、飲料水のフッ化物濃度が「最適」または低い地域に生涯住んでいる子供たちの間で使用されるNyvad視覚-触覚カリエス診断基準の信頼性を評価することであった。飲料水のフッ化物濃度がそれぞれ0.3および1.1ppm（0.3および1.1mg/l）の2つの地域で、150人の子供を2週間おきに2回臨床検査し、Thylstrup-Fejerskov指数（TF指数）を用いて歯のフッ素症について、およびNyvad視診式う蝕診断基準を用いてう蝕について調べた。歯のフッ素症の有病率は、1.1ppmのフッ化物地域では45％、0.3ppmのフッ化物地域では21％であった。虫歯の重複記録の結果を表面レベルで比較したところ、一致率（それぞれ91.7％と90.7％）とカッパ値（それぞれ0.73と0.72）にわずかな違いしか見られなかった。Bland-Altmanプロットを用いて個々のDFSカウントを検査間で比較し、その差の予測区間を推定したところ、低フッ化物地域の小児では記録間の差のばらつきが大きいことが確認された。予想に反して，顕著な歯面フッ素症の背景はう蝕記録の信頼性を低下させなかったが，歯面フッ素症のレベルが非常に低い場合には信頼性がわずかに低下するようであった．

The aim of this study was to assess the reliability of the Nyvad visual-tactile caries-diagnostic criteria when used among children who have been lifelong residents in areas with 'optimal' or low concentrations of fluoride in the drinking water. In each of two areas with drinking water fluoride concentrations of 0.3 and 1.1 ppm (0.3 and 1.1 mg/l) fluoride, respectively, 150 children were clinically examined twice, 2 wk apart, for dental fluorosis, using the Thylstrup-Fejerskov index (TF index), and for dental caries using the Nyvad visual-tactile caries criteria. The prevalence of dental fluorosis was 45% in the 1.1 ppm fluoride area and 21% in the 0.3 ppm fluoride area. When the results of the duplicate caries recordings were compared at the surface level, only minute differences were observed in the percentage agreement (91.7 and 90.7%, respectively) and in the kappa values (0.73 and 0.72, respectively). When individual DFS counts were compared across examinations using Bland-Altman plots and estimation of prediction intervals for the differences, we observed a greater variability of the differences between recordings among children from the low-fluoride area. Contrary to our expectations, a pronounced dental fluorosis background did not reduce the reliability of the caries recordings, which appeared to be slightly less reliable at very low levels of dental fluorosis.