Streptomyces globisporus 由来の溶菌酵素による洗口が人の乳歯齲蝕抑制に及ぼす効果

Abstract

It has been reported from our laboratory that a bacteriolytic enzyme derived from Streptomyces globisporus strain 1829 possessed the lytic action against strains of Streptococcus mutans, cariogenic Lactobacillus casei ATCC 4646 and Actinomyces viscosus strain T6. In the scanning electron microscopic studies, the cariogenic bacteria in the artificial dental plaque formed on the enamel surface in vitro were lyzed by the enzyme in situ. Similarly, the microorganisms in the naturally forming plaque on the tooth surface in vivo was also apparently affected by this enzyme. Furthermore, it was observed that the caries development in a group of hamsters, which were kept in the cariogenic diet #2000 containing the bacteriolytic enzyme, was signifficantly inhibited as compared with a group of hamsters which received the same diet without the enzyme. The effectiveness, however, of the enzyme on caries prevention in humans is not obscure. The purpose of the present experiment was to study the effect of the bacteriolytic enzyme on the inhibition of dental caries of children in a nursery school. One hundred sixteen children between 2 and 4 year age were divided into two groups, an experimental and control group. They received seven ml of mouthwash containing 3mg (3, 000 units) of the enzyme twice a day for washing in one minute their mouth after between meals. The procedure was continued for 18 months except holidays. In the control group, the conditions was the same as the experimental group except that the enzyme was replaced by 3mg of lactose. Every 3 months, the carious lesions were recorded by oral inspection. The increment of dmft during 12 months was 1.6 in experimental group (Gr.1) and 3.3 in control group (Gr.2). These figures led the percentage of inhibition at 51.5. The increment of dmft during 18 months was 2.2 in Gr.1 and 3.8 in Gr.2, and the percentage of dental caries inhibition at this stage was 42.1. Concerning the dmfs index, an increment of the value during 12 months was 4.8 in Gr.1 and 9.5 in Gr.2 with the percentage of inhibition was 49.5. The index at 18 months was 6.9 in Gr.1 and 11.1 in Gr.2, which indicates 37.9% of inhibition. The increment of pit and fissure caries surfaces during 12 months was 0.9 in Gr.1 and 1.7 in Gr.2, indicating 47.1% of inhibition. Similarly, an increment of the surfaces during 18 months was 1.1 in Gr.1 and 2.0 in Gr.2 with the percentage of inhibition was 45.0. In the case of smooth surface caries, the increment was 3.9 in Gr.1 and 7.8 in Gr.2 during 12 months with the percentage of inhibition was 50.0. The values at 18 months were 5.7 and 9.1 in respective groups with the percentage of inhibition was 37.4. The increment of expansion of carious lesions was 10.2 in Gr.1 and 18.4 in Gr.2 during 12 months, which indicates 44.6% of inhibition. The values at 18 months were 13.2 in Gr.1 and 24.1 in Gr.2 indicating 45.2% of inhibition. These results strongly suggested that a mouthwash containing the bacteriolytic enzyme from S. globisporus is a useful procedure for the dental caries prevention of deciduous teeth, and also applicable on the numerous groups of children.