title: A Microfluidics-based Pulpal Arteriole Blood Flow Phantom for Validation of Doppler Ultrasound Devices in Pulpal Blood Flow Velocity Measurement.
abstract: BACKGROUND
  Recently, Doppler ultrasound has been used for the measurement of pulpal blood flow in human teeth. However, the reliability of this method has not been verified. In this study, we developed a model to simulate arteriole blood flow within the dental pulp by using microfluidics. This arteriole simulator, or flow phantom, was used to determine the reliability of measurements obtained by using a Doppler ultrasound device.
  
  
  METHODS
  A microfluidic chip was fabricated by using the soft lithography technique, and blood-mimicking fluid was pumped through the channel by a microfluidic system. A Doppler ultrasound device was used for the measurement of flow velocity. The peak, mean, and minimal flow velocities obtained from the phantom and the Doppler ultrasound device were compared by using linear regression analysis and Pearson correlation coefficient. Bland-Altman analyses were performed to evaluate the velocity differences between the flow generated by the phantom and the flow measurements made with the Doppler ultrasound device.
  
  
  RESULTS
  The microfluidic system was able to generate the flow profiles as intended, and the fluid flow could be monitored and controlled by the software program. There were excellent linear correlations between the peak, mean, and minimal flow velocities of the phantom and those of the Doppler ultrasound device (r = 0.94-0.996, P < .001). However, the velocities were overestimated by the Doppler ultrasound device.
  
  
  CONCLUSIONS
  This phantom provides opportunities for research and education involving the Doppler ultrasound technique in dentistry. Although Doppler ultrasound can be an effective tool for the measurement of pulpal blood flow velocity, it is essential to validate and calibrate the device before clinical use.
authors.affiliation: Department of Conservative Dentistry and Oral Science Research Center, Yonsei University College of Dentistry, Seoul, Republic of Korea.
authors.forename: Dohyun
authors.initials: D
authors.lastname: Kim
authors.affiliation: Department of Conservative Dentistry and Oral Science Research Center, Yonsei University College of Dentistry, Seoul, Republic of Korea. Electronic address: sunghopark@yuhs.ac.
authors.forename: Sung-Ho
authors.initials: SH
authors.lastname: Park
mesh_terms: D001160:Arterioles / Q000502:physiology; D001783:Blood Flow Velocity; D003782:Dental Pulp / Q000098:blood supply*; D006801:Humans; D044085:Microfluidics / Q000295:instrumentation* / Q000379:methods; D019047:Phantoms, Imaging; D011673:Pulsatile Flow; D012039:Regional Blood Flow; D015203:Reproducibility of Results; D018608:Ultrasonography, Doppler / Q000295:instrumentation* / Q000379:methods
keywords: Doppler ultrasound; flow phantom; microfluidic chip; microfluidics; pulpal blood flow velocity