Abstract
A laser Doppler flowmeter (LDF) was adopted to assess pulpal vitality in luxated teeth. Identification of heartbeat synchronous fluctuations in the flowmetric signal was shown to be particularly important for the diagnosis of luxated non-sensitive teeth. In our method, a LDF probe was positioned at the buccal surface of each tooth at least 2 mm apart from the gingival margin, and the pulpal blood flow was non-invasively measured. The mean flowmetric value in the luxated tooth and the periodic fluctuation in each flowmetric signal were compared with those in control teeth of either healthy adults or healthy children. Low-frequency fluctuations (<0.1 Hz) as well as fluctuations synchronous with the heartbeat were observed in the flowmetric signals of vital teeth. Here we demonstrate that vitality in luxated teeth can be assessed more precisely by introducing power spectral analysis (maximum entropy method) into detection of both heartbeat synchronous and low-frequency fluctuations.
Flowmetric signals from luxated upper incisors of three patients in which the pulp s had survived the trauma showed prominent low-frequency (0.01-0.05 Hz) and heartbeat synchronous fluctuations after injury. These fluctuations were detectable even when the pulp chamber of the measured tooth was obscure and could not be confirmed on the X-ray film. Among the injured teeth, one incisor of a 7-year old patient showed a blood flow value nearly twice as high as the control value when it was measured 8 days after injury. A pulp chamber in an another injured tooth that accompanied root fracture was gradually narrowed and the blood flow value was decreased during 5-year observation after trauma. These results indicate that both low-frequency and heartbeat synchronous fluctuations are useful for the early diagnosis of pulpal vitality and that the LDF is a powerful tool for the evaluation of pulpal recovery after trauma.
