OptimizatiO n Of the Laser DO ppLer signaL acquisitiO n t iming fOr puLp VitaLity eVaLuatiO n

Objective: We evaluated the influence of acquisition time on the laser Doppler signals in vital upper anterior teeth. Due to the complexity of this technique, accurate signal acquisition requires a fixed and constant position, minimizing involuntary patient movement. The purpose of the study was to find optimal timing for signal acquisition and statistical data analysis, in which movement artifacts level are minimal. Materials and Method: In a group of 15 patients, pulp blood flow was determined in healthy maxillary anterior teeth. Signals were recorded with aid of a laser Doppler MoorLab and a straight optical probe, MP3b, held in place with a silicon impression, perpendicular on the vestibular surface of the tooth, in the cervical third. For each patient the signal was acquired during three minutes and subsequently processed: the signal was divided in six epochs of 30 seconds for each patient. Six acquisition intervals were thus obtained, starting from 0 point. The signal mean and standard deviations were analyzed and compared between these intervals in order to observe how reproducible and reliable a shorter acquisition can be. Results: Following statistical analysis, by applying the Friedman and Wilcoxon signed-rank test, there are no significant differences, from a statistical point of view, betweeen the first acquisition minute and the other intervals included in the study. Conclusions: The timing of the signal acquisition for a vitality test should and can be optimized, and this study concluded that acquisition time for laser Doppler signals could be reduced to a minute, without losing accuracy.