Dibdin G H
MRC Dental Group, University of Bristol Dental School, England.
Caries Res. 1990;24(4):231-8. doi: 10.1159/000261273.
Computer models can be powerful tools for studying complex interacting processes. The computer model of events in dental plaque during a cariogenic challenge described here simulates diffusion and metabolism of substrate, plus coupled diffusion/reaction of fourteen other species, charged and uncharged, including acidic metabolic products and fixed buffers. Its extension to deal with the effects of poor contact with bulk saliva when the plaque is presumed covered by a thin salivary film is here considered. Site-specific mixing rates between film and salivary pool were modelled phenomenologically, using data from the literature. Fast mixing was assumed during an initial carbohydrate intake phase (2 min sugar rinse), followed by site-dependent mixing and logarithmic clearance. The analysis also suggested a possible way of estimating local salivary film thickness. Increasing the halving time for exchange between film and bulk saliva was shown to prolong the pH minimum greatly, and to increase mineral loss. The respective roles of fixed buffers as stores of protons and of mobile buffers (especially bicarbonate) as exporters of protons from the inner plaque were emphasised.
计算机模型可以成为研究复杂相互作用过程的强大工具。这里描述的致龋挑战期间牙菌斑中事件的计算机模型模拟了底物的扩散和代谢，以及其他十四种带电和不带电物质的耦合扩散/反应，包括酸性代谢产物和固定缓冲剂。本文考虑了将其扩展以处理当牙菌斑被假定覆盖有薄唾液膜时与大量唾液接触不良的影响。使用文献数据，从现象学角度对膜与唾液池之间的位点特异性混合速率进行了建模。在初始碳水化合物摄入阶段（2分钟糖冲洗）假设快速混合，随后是位点依赖性混合和对数清除。分析还提出了一种估计局部唾液膜厚度的可能方法。结果表明，增加膜与大量唾液之间交换的半衰期会大大延长最低pH值，并增加矿物质流失。强调了固定缓冲剂作为质子储存库以及移动缓冲剂（尤其是碳酸氢盐）作为从菌斑内部输出质子的作用。
