有机弱酸对变链菌产酸作用的影响

目的 探讨有机弱酸苯甲酸、苹果酸、柠檬酸对口腔主要致龋菌变形链球菌的作用，并与氟化钠进行比较；探讨上述弱酸作为防龋剂的可能性。方法 将变形链球菌Smutans Ingbritt置入含有不同浓度的氟化钠、苹果酸、柠檬酸、苯甲酸的液体培养基TSB中生长48h，测定菌液的终末pH值，推测上述弱酸对细菌产酸能力的抑制作用，结果 苯甲酸、苹果酸、柠檬酸的抑菌所需浓度较氟化钠浓度高，且具浓度依赖性。结论 氟化钠抑制变形链球菌产酸作用最好；而有机弱酸苯甲酸、苹果酸、柠檬酸在较高浓度下，才有不同程度抑制变形链球菌产酸作用，但该浓度却有可能对牙釉质产生脱矿作用。

Comparison of Effect on S.mutans Producing Acid Ability between Organic Weak Acid and Fluoride

OBJECTIVE: To figure out the effects of organic weak acids, benzoate, citric acid and malic acid on the main cariogenic bacteria S.mutans Ingbritt. To evaluate the possibility of above weak acids as anti-caries reagents. METHODS: S.mutans Ingbritt was inoculated into tryptic soy broth containing different concentrations of fluoride, benzoate, citric acid and malic acid, grew in anaerobic conditions at 37 degrees centigrade for 48h. The final pH values of suspension were measured. RESULTS: Fluoride had best inhibitory effect on S.mutans Ingbritt in low concentrations, whereas other 3 weak acids, benzoate, citric acid and malic acid could inhibit S.mutans Ingbritt in a higher concentrations. The order of effectiveness was fluoride>malic acid>benzoate>citric acid. CONCLUSION: Fluoride has the best inhibitory effect on S.mutans producing acid ability. Though weak acids benzoate, malic acid and citric acid in high concentration had different inhibitory effects on S.mutans Ingbritt, however high concentration of organic acids can make enamel demineralization.