Nondestructive testing in human teeth using a leaky Lamb wave device

Area of Science:

• Materials Science
• Biomedical Engineering
• Acoustics

Background:

• Ultrasonic nondestructive testing (NDT) is crucial for evaluating material integrity.
• Accurate layer thickness measurement in human teeth is vital for dental diagnostics.
• Traditional methods may lack precision or in vivo applicability.

Purpose of the Study:

• To investigate the use of leaky Lamb waves for ultrasonic NDT of human teeth layer thickness.
• To identify an optimal mode for frequency-controllable ultrasound beam radiation.
• To demonstrate in vivo layer thickness measurement using an acoustic coupler.

Main Methods:

• A Lamb wave interdigital transducer was mounted on a layered substrate (piezoelectric ceramic and acrylic).
• The system operated at a liquid-solid boundary with a water layer as an acoustic coupler.
• Higher-order leaky Lamb wave modes were analyzed for their phase velocity relative to human teeth.

Main Results:

• The fourth mode of the leaky Lamb wave exhibited favorable frequency-controllable radiation angles.
• This mode's phase velocity exceeded the longitudinal wave velocity in human teeth.
• In vivo layer thickness measurements were successfully achieved by analyzing reflected ultrasound echoes.

Conclusions:

• Leaky Lamb waves, particularly the fourth mode, are suitable for ultrasonic NDT of teeth.
• The developed method allows for precise, in vivo layer thickness assessment.
• This technique offers a promising approach for dental diagnostics and evaluation.