Effects of an intravenous infusion of Ringer's solution on eruption rates of incisor teeth in anesthetized rats

Objective. The vasculature within the socket is reportedly involved in determining the position of continuously erupting teeth. Thus, loss of body fluid in anesthetized rats, which would affect the vascular physiology, should influence tooth movement. We investigated the effects of an infusion of Ringer's solution on the systemic arterial blood pressure, regional blood flow at the base of the incisor, and axial tooth movement in anesthetized rats to determine the cause of tooth displacement. Material and methods. In the experimental group, the animals received intravenous infusions of Ringer's solution at 27 mu l/min for 13 h. In the control group, the animals did not receive the infusion. Results. The infusion of Ringer's solution suppressed an increase of the mean arterial blood pressure from 86 to 80 mmHg and a decrease of the regional blood flow from 170 to 217 mV, and increased the eruption rate from 267 to 361 mu m/13 h during the experimental period. There was a positive correlation between the eruption rate and regional blood flow, and a negative correlation between the blood pressure and regional blood flow. Conclusions. These results suggest that an infusion of Ringer's solution can cause an increase in the regional blood flow, resulting in increased fluid volume, elevated intra-socket pressure, and increased eruptive movement. It is possible that the regional vascular volume and/ or pressure within the socket play an important role in determining the position of the incisor.