Heyeraas K J, Kvinnsland I
Department of Physiology, University of Bergen, Norway.
Proc Finn Dent Soc. 1992;88 Suppl 1:393-401.
The initial vascular reactions during inflammation are vasodilation and increased vessel permeability. Both these basic reactions cause increased pulpal fluid volume. In the dental pulp the inflammatory vascular reactions take place in a rigid enclosed dentin chamber, which to some extent makes the pulp vulnerable. Due to this lack of distensibility any gain in pulpal volume will necessarily increase the pulpal tissue pressure. If the tissue pressure rises to the same level as the blood pressure it will compress the pulpal vessels, thus counteracting a beneficial blood flow increase during inflammation. Using the micropuncture technique and laser Doppler flowmetry we have performed simultaneous measurements of tissue pressure and blood flow in the cat dental pulp during neurogenic inflammation. Sensory nerve stimulation caused a rise both in blood flow and tissue pressure. Our findings thus strongly suggest that the increased pulpal tissue pressure promote fluid absorption back into the blood. If, in theory, plasma proteins and other macromolecules had leaked out during sensory nerve stimulation they must have been successfully removed by lymphatics, unless the tissue pressure would have risen to the same level as the capillary blood pressure causing a fall in PBF. This was not found. On the contrary, increased blood flow was measured, even in experiments lasting for more than 8 hours. It is therefore concluded that the pulp may have a beneficial blood flow increase during inflammation in spite of simultaneously increased tissue pressure.
炎症过程中的初始血管反应是血管扩张和血管通透性增加。这两种基本反应都会导致牙髓液量增加。在牙髓中，炎症性血管反应发生在一个坚硬封闭的牙本质腔内，这在一定程度上使牙髓变得脆弱。由于缺乏扩张性，牙髓体积的任何增加必然会增加牙髓组织压力。如果组织压力上升到与血压相同的水平，它将压迫牙髓血管，从而抵消炎症期间有益的血流量增加。我们使用微穿刺技术和激光多普勒血流仪，在猫牙髓神经源性炎症期间同时测量了组织压力和血流量。感觉神经刺激导致血流量和组织压力均升高。因此，我们的研究结果强烈表明，牙髓组织压力升高促进了液体回吸收入血液。从理论上讲，如果在感觉神经刺激期间血浆蛋白和其他大分子已经渗漏出来，它们一定已经被淋巴管成功清除，除非组织压力上升到与毛细血管血压相同的水平，导致牙髓血流量下降。但并未发现这种情况。相反，即使在持续超过8小时的实验中，也测量到了血流量增加。因此可以得出结论，尽管组织压力同时增加，但牙髓在炎症期间可能会有有益的血流量增加。
