Doppler ultrasound to detect pulpal blood flow changes during local anaesthesia

Yoon MJ, Lee SJ, Kim E, Park SH. Doppler ultrasound to detect pulpal blood flow changes during local anaesthesia. International Endodontic Journal, 45, 83-87, 2012. Aim To examine whether Doppler ultrasound can detect changes in pulpal blood flow after infiltration anaesthesia. Methodology Changes in pulpal blood flow in maxillary central incisor teeth of 18 patients (mean age 26.7years, 13 men, five women) after infiltration anaesthesia were examined. Before infiltration anaesthesia, the pulpal blood flow was measured using Doppler ultrasound. A local anaesthetic solution containing 2% lidocaine with 1:80000 epinephrine was injected into the submucosa above the experimental tooth. The Doppler ultrasound test was carried out at 5, 10, 20, 30, 45 and 60min after infiltration. The parameters were Vas (maximum linear velocity, cms ^-1), Vam (average linear velocity, cms ^-1) and Vakd (minimum linear velocity, cms ^-1), which are indicators of the level of blood flow. The mixed procedure at the 95% confidence interval was used to examine the changes in pulpal blood flow after the injection. Results The linear velocity profiles (Vas, Vam, and Vakd) decreased sharply 5min after anaesthesia and then reduced continuously for 30min. The maximum degree of blood flow reduction in Vas, Vam and Vakd was 58%, 83% and 82%, respectively. After 30min, the linear velocities increased gradually. The Vam returned to the pre-anaesthesia state at 60minutes but the Vas and Vakd did not recover completely. Conclusions Doppler ultrasound can detect changes in pulpal blood flow after infiltration anaesthesia. In the future, Doppler ultrasound can be used as a tool for measuring pulpal blood flow.