口臭と歯肉縁下微生物叢の相関に関する臨床的研究

[Clinical study of the correlation between bad breath and subgingival microflora].

抄録

口臭の発生における歯肉縁下微生物叢の役割を調べるために、歯肉縁下微生物の暗視野顕微鏡検査と揮発性硫黄化合物のガスクロマトグラフィー分析を行った。被験者（女性11名、男性13名、24～61歳）は、嗅覚的判断による明らかな口臭の有無により、口臭あり群（B群、n＝13）と口臭なし群（N群、n＝11）の2群に分けられた。ガスタイトシリンジを用いて5mlの口腔内空気サンプルを採取し、ガスクロマトグラフに直接注入した。口腔空気中に生成された揮発性硫黄化合物をガスクロマトグラフで分析し、CH3SHの体積を測定した。歯肉縁下プラークサンプルは、各被験者のプロービング深度の最も深い部位から滅菌したペーパーポイントで採取した。サンプルは暗視野顕微鏡で検査され、無作為に選択された100フィールドの細菌が、以下の形態学的カテゴリーのいずれかにパーセンテージベースで分類された：(1)スピロヘータ、(2)運動性桿菌、(3)フィラメント、(4)フシ状、(5)直鎖桿菌、および(6)球菌。各カテゴリーの細菌数から1mlあたりの総細胞数を算出した。各群の独立した2平均値の比較は、ノンパラメトリック値に対するWilcoxonの順位和検定により行った。細菌データと口腔内のCH3SH値との相関は、スピアマン順位相関係数を用いて求めた。1.2群間の微生物叢には有意差が存在した：B群のスピロヘータおよび運動性桿菌の割合は、N群よりも有意に高かった（pは0.01未満）。B群の総細胞数はN群より有意に多く、統計学的に有意差があった（pは0.01未満）。2.口腔内のCH3SH値は、スピロヘータの割合、運動性桿菌の割合、および総細胞数と正の相関を示した。これらの結果は、歯肉縁下微生物が口臭の発生に一定の役割を果たしているという見解と一致している。さらに、スピロヘータと運動性桿菌が口臭発生のメカニズムに関係していることが示唆された。

A dark field microscopic examination of subgingival microorganisms and gas chromatographic analysis of volatile sulphur compounds were employed to investigate the role of subgingival microflora in the production of bad breath. Subjects (11 female, 13 male; aged 24 to 61) were divided into the following 2 groups on the basis of apparent bad breath by the olfactory judgement; bad breath group (group B, n = 13), and no bad breath group (group N, n = 11). A gas tight syringe was employed to withdraw 5 ml mouth air samples, which were injected directly into the gas chromatograph. Volatile sulphur compounds produced in mouth air were analyzed by gas chromatograph to determine volumes of CH3SH. Subgingival plaque samples were taken with sterilized paper points from the deepest site of probing depth in each subjects. The samples were examined by means of dark field microscopy and 100 bacteria in randomly selected fields were classified on a percentage basis into one of the following morphological categories: (1) spirochetes, (2) motile rods, (3) filaments, (4) fusiforms, (5) straight rods, and (6) coccoid cells. Total cell counts per 1 ml were calculated from bacterial counts of each categories. Comparison of 2 independent means from each groups were carried out by Wilcoxon's rank sum test for nonparametric values. Correlations of bacterial data with CH3SH values in mouth air were determined by means of Spearman rank correlation cofficient. Results were as follows; 1. Significant differences existed in the microbial flora between the 2 groups: percentage of spirochetes and motile rods in group B were significantly higher than those in group N (p less than 0.01). Total cell counts of group B were significantly greater than group N, and there were statistically significant differences (p less than 0.01). 2. CH3SH values in mouth air had positive correlations with the percentage of spirochetes, the percentage of motile rods, and total cell counts. These results are consistent with the view that subgingival microorganisms play a certain role in the production of bad breath. Moreover, it was suggested that spirochetes and motile rods are related to the mechanism of bad breath production.