Dawes C, Watanabe S, Biglow-Lecomte P, Dibdin G H
Department of Oral Biology, Faculty of Dentistry, University of Manitoba, Winnipeg, Canada.
J Dent Res. 1989 Nov;68(11):1479-82. doi: 10.1177/00220345890680110201.
Previously, we studied the clearance rates of KCl from agarose gels positioned at different locations in the mouth, and showed that the rates were much slower than when clearance was into a well-stirred solution. We designed the present in vitro study to test the effect on KCl clearance of the velocity of a 0.1-mm-thick film of water flowing over an agarose gel of the same diameter and composition as those used in vivo. The thickness of the salivary film overlying dental plaque has been estimated to be about 0.1 mm, and we assumed that when clearance rates in vitro matched those found in vivo, velocities of the fluid film (in vitro) and the salivary film (in vivo) must be equal. On this basis, it was calculated in the present experiments that when salivary flow was unstimulated, the velocity of the salivary film at the level of the teeth varied between about 0.8 mm/min (upper-anterior buccal region) and 8.0 mm/min (lower-anterior lingual region). When salivary flow was stimulated, this was estimated to increase the velocity of the salivary film from 2 to 40 times, depending on the location in the mouth. It is postulated that the slow movement of the salivary film when flow is unstimulated allows for accumulation of diffusants from dental plaque, which reduces the concentration gradient for diffusion from plaque and prolongs the clearance time of such metabolic products as acid.
此前，我们研究了置于口腔不同位置的琼脂糖凝胶中氯化钾的清除率，结果表明，其清除率比在充分搅拌的溶液中清除时要慢得多。我们设计了本项体外研究，以测试厚度为0.1毫米的水膜在与体内使用的直径和成分相同的琼脂糖凝胶上流动的速度对氯化钾清除的影响。据估计，覆盖在牙菌斑上的唾液膜厚度约为0.1毫米，我们假设，当体外清除率与体内发现的清除率相匹配时，流体膜（体外）和唾液膜（体内）的速度必须相等。在此基础上，本实验计算得出，在非刺激性唾液流情况下，牙齿水平处唾液膜的速度在约0.8毫米/分钟（上前颊区）至8.0毫米/分钟（下前舌区）之间变化。当唾液流受到刺激时，据估计，根据口腔内的位置不同，唾液膜的速度会增加2至40倍。据推测，在非刺激性唾液流情况下，唾液膜的缓慢移动会使牙菌斑中的扩散物质积聚，这会降低从牙菌斑扩散的浓度梯度，并延长酸等代谢产物的清除时间。
