【摘要】 作者用五种致龋菌,体外混合培养,模拟牙菌斑生态系,研究pH变化与时间的关系。结果表明,随时间变化,混合致龋菌培养液的pH逐渐降低;12小时内,pH由7.0降至5.0以下;继续延长培养时间,pH无明显下降,而维持在低pH状态。更多还原

【Abstract】 The relation of pH changes to time bya simulated dental plaque ecosystem com-posed of five cariogenic bacteria was studiedin vitro, and the abilities to reduce the pHin sucrose, glucose and fructose media werecompared. The pH levels of the centrifugedsupernatants of the mixed bacterial culturesat different intervals were quantitativelydetermined by pH meter. The resultsshowed that the pH of the mixed cariogen-ic strains dropped gradually with incuba-tion time; within 12 hours, the pH de-creased from 7.0 to 5.0 or lower.When thetime was prolonged, the pH did not obvi-ously change any more but maintained alower pH level. The abilities of sucrose andglucose to reduce the pH were significantlygreater than that of fructose (P<0.05). Itis suggested that sucrose and glucose aremore easily being utilized by cariogenicbacteria than fructose.更多还原