乳歯列期における glucosyltransferase 遺伝子発現と環境要因について The Gene Expression of Glucosyltransferase in Mutans Streptoccoci and the Environmental Factors during the Deciduous Dentition Period
著者は齲蝕抑制の確立を目指し,乳歯列期小児の齲蝕と環境要因との関連および<I>Streptococcus mutans</I>のglucosyltransferase B遺伝子(<I>gtfB</I>)と<I>Streptococcus sobrinus</I>のglucosyltransferase I遺伝子(<I>gtfl</I>)の発現と齲蝕との関連について検討を行った。その結果,<BR>1.齲蝕と環境要因との関連性は,質問紙調査から「歯磨き回数」,「仕上げ磨きの習慣性」の口腔衛生習慣,「間食時間の規則性」の間食習慣,「保護者の認識度」等の生活環境と「ミューカウント®」の齲蝕活動性が乳歯齲蝕罹患状況と関連性が認められた。<BR>2.<I>gtf</I>発現状況では,標準株の発現量より高値を示した園児の<I>gtfB</I>発現者率は無齲蝕群が14.3%,低齲蝕群が41.7%,高齲蝕群が100%に認められ,<I>gtfB</I>発現量は高齲蝕群で高い発現量を示した。また,<I>gtfl</I>発現者率は低齲蝕群が8.3%,高齲蝕群が30.0%に認められ,<I>gtfl</I>発現を認めた園児は<I>gtfB</I>に比較し少なかった。以上より,乳歯齲蝕は主に<I>gtfB</I>の発現量ならびに付随した<I>gtfl</I>発現量が齲蝕発症に関与している可能性が示唆され,これらの発現状態下では齲蝕活動性が高くなると思われた。また,保護者の認識度を含めた生活環境の改善が小児の齲蝕発症予防と重症化の抑制対策として重要なアプローチであることが示唆された。
The aim of this study was to establish of caries prevention, and to examine the relationship between dental caries and surroundings factors, based on life habits and caries activity during the deciduous dentition period. Furthermore, since glucosyltransferase, which is a synthetic enzyme of water insoluble glucan in mutans streptococci, is strongly involved in the occurrence of caries, the relationship between deciduous tooth caries and the expression of <I>gtfB</I> in <I>Streptococcus mutans</I> or <I>gtfl</I> in <I>Streptococcus sobrinus</I> was also investigated.<BR>In this study, I research on 114 children in Nagano, and performed a caries activity test (Mucount®) and investigated environmental factors, by asking parents to fill out questionnaires. I also collected dental plaque from brushing from 36 children.<BR>χ<SUP>2</SUP>analysis of the relationship between dental caries and environmental factors was performed. The expression of <I>gff</I> was also examined using Real-time PCR, and comparison evaluation was carried out by classifying the children into three groups based on the severity of their dental caries.<BR>Among the results of the Real-time PCR analysis, the incidence of <I>gtfB</I> expression was 14.3% in the non-caries group,41.7% in the low caries group, and 100.0% in the high caries group, there was considerable <I>gtfB</I> expression in the high caries group. The incidence of <I>gtfl</I> expression was 8.3% in the low caries group, and 30.0% in the high caries group. More <I>gtfB</I> expression was consequently, noted in the caries group, and the <I>gtfl</I> expression was lower than the <I>gtfB</I> expression.<BR>Furthermore, there is a tendency that for children who showed <I>gtfB</I> expression, the living environment was irregular, and the level of knowledge of the parents concerning caries was low.<BR>These results suggested the occurrence of caries in deciduous tooth is related not only to the number of <I>Streptococcus mutans</I> and <I>Streptococcus sobrinus</I>, but also to pathogenic factors such as the <I>gtfB</I> and <I>gff</I>l expressions; Caries activity became higher under these conditions. It was also suggested that improvement in living environment is an important approach to prevent caries in deciduous tooth and to decrease the occurrence of serious caries.<BR>It is considered that understanding of living environment, of the children and the bacterial risk during growth is useful for motivating their parents as an index of instruction in caries prevention.
小児歯科学雑誌 44(1), 55-66, 2006-03-25