Design and implementation of noninvasive laser imaging system for human teeth carious detection and removal

Abstract

Background: Knowledge of heat transfer in biological bodies has many diagnostic and therapeutic applications involving either raising or lowering of temperature, and often requires precise monitoring of the spatial distribution of thermal histories that are produced during a treatment protocol. Aim: This paper, therefore, aims to design and implementation a laser therapeutic and imaging system used for carious tracking and drilling by developing a mathematical algorithm using Hilbert transform for edge detection of photothermal imaging. Photothermal imaging has the ability to penetrate and yield information about an opaque medium well beyond the range of conventional optical imaging. Method: Owing to this ability, Q-switching neodymium-doped yttrium aluminium garnet laser at wavelength 1064 nm has been extensively used in human teeth to study the subsurface deposition of laser radiation. Results: The high absorption coefficient of the carious as compared to the normal region contributes to a greater increase in temperature generating infrared thermal radiation captured by the high resolution thermal camera. Changing the pulse repetition frequency of the laser pulses affects the penetration depth of the laser, which can provide three-dimensional images in arbitrary planes and allow imaging deep within a solid tissue. Conclusions: Photothermal imaging with 2-D Hilbert transform algorithm is a powerful tool for human carious detection