ABSTRACT

Background: Dental caries etiology is attributed to a dysbiotic imbalance within the plaque microbiome leading to a dominance of strong acidogens. Some studies that investigate the link between acidogens and caries quantify the recovery of acid tolerant strains on acid agar as a measure of acidogenic potential. This methodology assumes that acidogenic potential and acid tolerance are directly related.

Aim: The validity of that assumption was investigated by statistically evaluating that relationship using streptococci recovered from children with or without a history of dental caries.

Methods: Thirty streptococcal isolates were isolated from each of 13 subjects. Acidogenicity was quantified by measuring the terminal pH after overnight growth in Brain Heart Infusion (BHI) and Chemically Defined Medium (CDM). Acid tolerance was quantified by measuring the lowest pH acid agar displaying growth. Results: A significant difference in acidogenicity in CDM between levels of acid tolerance was found, but no significant difference in acidogenicity in BHI was noted. Moreover, there were no significant interactions between acid tolerance and caries history on acidogenicity measures in either medium.

Conclusion: An ability to grow on acid agar below pH 5.0 is best aligned with strong acidogenicity and best able to distinguish between subjects with differing caries histories.

摘要

背景：龋齿的病因归因于菌斑微生物组中的致病菌失衡，导致强酸原体占主导地位。一些研究产酸剂和龋齿之间联系的研究量化了在酸琼脂上耐酸菌株的回收率，以此作为产酸潜力的量度。该方法假设产酸潜力和耐酸性直接相关。

目的：通过使用从有或没有龋齿病史的儿童中回收的链球菌统计学评估这种关系，对这一假设的有效性进行了研究。

方法：从13名受试者中分离出30株链球菌。通过在脑心浸液（BHI）和化学成分确定的培养基（CDM）中过夜生长后测量末端pH值来量化产酸性。通过测量显示出生长的最低pH酸琼脂来量化酸耐受性。结果：发现耐酸水平之间的CDM产酸能力有显着差异，但BHI产酸能力没有显着差异。此外，在任何一种培养基中，酸耐受性和龋齿病史之间在酸原性测量方法上都没有显着的相互作用。

结论：在pH 5.0以下的酸性琼脂上生长的能力与强酸原性最好地吻合，并且最能够区分具有不同龋病历史的受试者。