Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil.
J Appl Oral Sci. 2010 Jul-Aug;18(4):316-34. doi: 10.1590/s1678-77572010000400002.
Despite a plethora of in situ studies and clinical trials evaluating the efficacy of fluoridated dentifrices on caries control, in vitro pH cycling models are still broadly used because they mimic the dynamics of mineral loss and gain involved in caries formation. This paper critically reviews the current literature on existing pH-cycling models for the in vitro evaluation of the efficacy of fluoridated dentifrices for caries control, focusing on their strengths and limitations. A search was undertaken in the MEDLINE electronic journal database using the keywords "pH-cycling", "demineralization", "remineralization", "in vitro", "fluoride", "dentifrice". The primary outcome was the decrease of demineralization or the increase of remineralization as measured by different methods (e.g.: transverse microradiography) or tooth fluoride uptake. Inclusion of studies, data extraction and quality assessment were undertaken independently and in duplicate by two members of the review team. Disagreements were solved by discussion and consensus or by a third party. One hundred and sixteen studies were included, of which 42 addressed specifically the comparison of dentifrices using different pH-cycling models. The other studies included meta-analysis or reviews, data about the effect of different fluoride sources on de-remineralization, different methods for analysis de-remineralization and chemical variables and characteristics of dental hard tissues that might have influence on de-remineralization processes. Generally, the studies presented ability to detect known results established by clinical trials, to demonstrate dose-related responses in the fluoride content of the dentifrices, and to provide repeatability and reproducibility between tests. In order to accomplish these features satisfactorily, it is mandatory to take into account the type of substrate and baseline artificial lesion, as well as the adequate response variables and statistical approaches to be used. This critical review of literature showed that the currently available pH-cycling models are appropriate to detect dose-response and pH-response of fluoride dentifrices, and to evaluate the impact of new active principles on the effect of fluoridated dentifrices, as well as their association with other anti-caries treatments.
尽管有大量的原位研究和临床试验评估了含氟牙膏在控制龋齿方面的功效，但体外 pH 循环模型仍被广泛应用，因为它们模拟了龋齿形成过程中涉及的矿物质损失和获得的动态。本文批判性地回顾了现有的 pH 循环模型在评估含氟牙膏控制龋齿功效的体外研究文献，重点关注其优缺点。使用关键词“pH 循环”、“脱矿”、“再矿化”、“体外”、“氟化物”、“牙膏”，在 MEDLINE 电子期刊数据库中进行了搜索。主要结果是通过不同方法（例如：横向显微射线照相术）或牙齿氟摄取量来衡量的脱矿作用减少或再矿化作用增加。研究的纳入、数据提取和质量评估由两名评审小组成员独立进行，然后进行重复。通过讨论和达成共识或由第三方解决分歧。共纳入 116 项研究，其中 42 项专门研究了使用不同 pH 循环模型的牙膏的比较。其他研究包括荟萃分析或综述、关于不同氟源对脱矿作用的影响的数据、不同的脱矿作用分析方法以及可能影响脱矿作用过程的牙齿硬组织的化学变量和特征。一般来说，这些研究能够检测到临床试验确定的已知结果，证明牙膏中氟含量的剂量反应关系，并在测试之间提供重复性和再现性。为了令人满意地实现这些特征，必须考虑基质类型和基线人工损伤，以及要使用的适当响应变量和统计方法。对文献的批判性回顾表明，目前可用的 pH 循环模型适用于检测氟化物牙膏的剂量反应和 pH 反应，以及评估新活性成分对含氟牙膏效果的影响，以及它们与其他抗龋治疗的关联。
