Blood flow changes in the dental pulp of the cat and rat measured simultaneously by laser Doppler flowmetry and local ¹²⁵I clearance

Abstract

Blood flow changes in the dental pulp of lower canine teeth of mature cats and incisors of mature rats were investigated with simultaneous laser Doppler flowmetry and local 125I-clearance (wash-out) during electrical sympathetic stimulation, efferent stimulation of n. alveolaris inferior (IAN) (cats) and i.a. infusions of substance P (SP) (cats). Stimulation (1-4 Hz, 4 V., 1.5 ms) of the cervical sympathetic trunk produced frequency-dependent decreases in both laser Doppler output and disappearance rate of iodine tracer from the dental pulp. For the effects of sympathetic stimulation, the correlation (r2) between the results obtained by the two methods was 0.89 (12 observations, six animals). Blood flow measurements by both methods were increased following i.a. infusions of SP (r2 = 0.64, six observations, three animals). However, upon stimulation of IAN (10 Hz 10 V, 5 ms) the laser Doppler flow values showed an increase while the local 125I clearance rate was unaffected or even decreased. The discrepancy between the results obtained following IAN stimulation indicates that the two methods reflect blood flow changes in different parts of the pulpal vascular bed and that the flow is unevenly distributed to these parts during antidromic IAN stimulation. The laser Doppler flowmetry seems to reflect the total blood flow in the coronal pulp and therefore this non-invasive method may be useful for monitoring blood flow changes in the tooth.

Oral mucosal blood flow following dry ice stimulation in humans

“…A vasoconstrictor response in the dental pulp and oral mucosa was provoked by activation of the sympathetic nerves in experimental animals. Here, in addition to noradrenalin, neuropeptide Y probably is involved in sympathetic vascular control in oral tissues [29].…”

Inhibitory effects of excess sympathetic activity on parasympathetic vasodilation in the rat masseter muscle

“…The masseter muscle was ascertained by the naked eye. The LDF values obtained in this way represent the blood flow in the superficial vessels of the masseter muscle (8,22). Electrical calibration for zero blood flow was performed for all recordings.…”

Measurement of Blood Perfusion in the Dental Pulp with Laser Doppler Flowmetry

“…One of the major draw backs of this technique is that measurement results can not be expressed in absolute units but must instead be giv en in arbitrary units based on the calibration of the machine in a zero reflectance and a standard motility solution. Nonetheless, the accuracy and reliability of LDF in measuring blood flow in teeth has been confirmed in animal models by comparing the technique with other methods used to measure the perfusion of the dental pulp [2,3]. Clinical applications of LDF in dentistry have been primarily in the area of traumatology, where it has been used to monitor pulp vitality in luxated teeth over time [4,5], A recent study has reported the accuracy of LDF in distinguishing between vital and nonvital teeth [6].…”