Abstract
Laser Doppler flowmetry (LDF) was applied to measure pulpal blood flow in immatured human permanent incisors.
Eighteen young patients aged 6-12 and 7 adult volunteers participated in this study.
Heart beat synchronous oscillations were present in the recording singal from all of the matured vital teeth, which suggested that the pulpal blood flow was identified when the pulsatile oscillations were recognized in the LDF signal.
While the pulsatile oscillations were not so clear as were observed in matured teeth, LDF values of 26 imrnatured teeth (9.3±2.4) were slightly higher than those of 11 matured teeth (8.3±2.1). LDF values of 8 nonvital teeth (2.1±1.6)were distinctly lower than those of the vital teeth.
These observations suggested that the difference of LDF values between vital and nonvital teeth might be effective for identifying the pulpal vitality.
Five of the 26 immatured teeth, classified as a least formed apex group, were irresponsive to electrometric pulp testing. Although the LDF values of these teeth were apparently higher than the mean value of nonvital teeth, the vitality of these immatured teeth was not easily identified because the LDF values of the nonvital teeth occasionally exceeded the background level and showed irregular oscillations by artifacts such as blood flow in the adjacent gingiva and scattered laser beams in hard tissue.
Based on these facts, we monitored the pulpal blood flow and ECG simultaniously and analyzed the power spectra of both recording signals through a Fast Fourier Transform (FFT).
Prominent heart beat power was present in both ECG and LDF signals even from the least formed apex group but was not present in LDF signals from the nonvital teeth.
It would be useful for diagnosis of pulpal vitality of immatured teeth to compare the power spectrum of LDF signals with that of ECG.