Influence of Food Preservatives on Dental Caries

在过去25年中，某些人群的龋齿患病率已显著降低。观察到的减少主要归因于饮用水中氟化物暴露的增加和氟化牙膏的使用。在同一时期，食品防腐剂如苯甲酸盐、山梨酸盐、丙酸盐、水杨酸盐的使用也急剧增加。例如，美国苯甲酸盐的消费量从1970年的180万吨增加到1995年的2550万吨。因此，人类不断地暴露于防腐剂中;在美国消费苏打水的人平均每天摄入800毫克苯甲酸盐。食物防腐剂是弱酸，其抗菌作用与氟化物相似，即在低pH值下，防腐剂通过细菌细胞膜扩散，酸化细胞质，使微生物对酸敏感。耐酸性是致龋微生物的一个特征。弱酸也可能影响细菌膜。我们有初步的数据表明，苯甲酸盐减少了微生物的糖基转移酶的生产，而不影响酶的活性。这一观察结果与早期的报告（Bowen和休伊特，1971）一致，该报告表明生长培养基中的氟化物影响变形链球菌产生葡糖基转移酶。在大鼠中进行的初步研究的数据表明，苯甲酸盐和非甾体抗炎药，例如酮洛芬（弱酸），可增强氟化物的防龋作用，并且许多药物可抑制变形菌群。本研究的目的是探讨公认的食品防腐剂单独或与氟化物结合对龋齿的影响，在我们的动物模型。这项研究的结果可能会导致确定一种新的方法，提高氟化物的有效性。

The prevalence of dental caries has been reduced significantly in some segments of the population over the past 25 years. The observed reduction has been attributed largely to increased exposure to fluoride in drinking water and use of fluoridated dentrifrices. During the same time period the use of food preservatives e.g. benzoates, sorbates, propionates, salicylates has also increased dramatically. For example the consumption of benzoate in the U.S. has increased from 1.8 million tons in 1970 to 25.5 million in 1995. Thus humans are exposed to preservatives constantly; persons in the U.S. consuming the average amount of soda ingest 800 mg of benzoate daily. Food preservatives are weak acids and exert their anti-microbial effect in a manner similar to that of fluoride i.e. at low pH values they diffuse undissociated through the bacterial cell membrane and acidify the cytoplasm, rendering microorganisms sensitive to acid. Acid tolerance is a characteristic of cariogenic organisms. Weak acids may also affect bacterial membranes. We have preliminary data which show that benzoates reduces the production of glycosyltransferase by microorganisms without affecting the enzymatic activity. This observation is consistent with an earlier report (Bowen and Hewitt, 1971) which showed that fluoride in growth medium influences the production of glucosyltransferase by mutans streptococci. Data from preliminary studies conducted in rats show that benzoate and non-steroidal anti- inflammatory agents e.g. ketoprofen (weak-acid) enhances the cariostatic effect of fluoride and also many suppress mutans populations. The purpose of the present study is to explore the effects of well-recognized food preservatives alone or in combination with fluoride on caries in our animal model. The outcome of this research could result in identifying a novel method of enhancing the effectiveness of fluoride.