Photothermal radiometric quantitative detection of the different degrees of demineralization of dental enamel by acid etching

Abstract

Photothermal radiometric (FD-PTR or PTR) signals from human teeth have been used toward detecting an artificial surface demineralization. The aim of the study is to characterize PTR signals by using controlled mineral loss from human enamel to mimic surface and subsurface dental caries. At a fixed modulation frequency, an Ar + ion laser was used as a light source to scan across the tooth surface, and an MCT infrared detector was used for measuring the PTR signals. Several human molar teeth were etched using 37% phosphoric acid etching gel and scanned across the etched region at 30 Hz. PTR amplitude from the etched region shows that the signal decreases with increasing etching time. The PTR phase also shows the same behavior with the amplitude and better contrast between different etching times. The PTR technique could thus be used to detect early surface demineralization and may give the examiner quantitative information of the degree of demineralization in dental caries.

A Clinical Challenge & Solution: Detecting Cracks in Teeth Using PTR-LUM-The Canary System; A Case Report

“…These harmless pulses of laser light allow a clinician to examine sub-surface caries and crystal structure defects, up to 5 mm. below the surface [27,28]. Carious lesions modify the thermal properties (PTR) and glow (LUM) from the healthy teeth.…”

Detection of Caries Around Resin-Modified Glass Ionomer and Compomer Restorations Using Four Different Modalities In Vitro

“…Surface debris and stain was removed from the teeth, but the caries lesions were not touched. The teeth were stored in distilled water to avoid dehydration, using the protocol established in our earlier studies [ 39 , 47 , 48 ]. Before examination each tooth was removed from the vial, rinsed thoroughly with distilled water for 20 s and air-dried for five seconds.…”

“…The Canary System (Quantum Dental Technologies, Toronto, ON, Canada) using a 660 nm <50 mW, pulsed laser, combines laser photothermal radiometry (PTR) and modulated luminescence (LUM) amplitude and phase signals to detect and assess caries [ 39 ]. Pulses of laser light focused on a tooth cause, the tooth to “glow” or luminesce (LUM) and releases heat (PTR).…”

“…Pulses of laser light focused on a tooth cause, the tooth to “glow” or luminesce (LUM) and releases heat (PTR). The system analyzes the response of the re-emitted radiation (luminescence or LUM) and the thermal behavior of the emitted infrared photons (PTR) to provide information about the status of the tooth’s crystal structure [ 39 ]. The CS measures both the amplitude and phase delay of the PTR and LUM signals and then converts these signals into a measurement or Canary Number (CN).…”

“…The CS measures both the amplitude and phase delay of the PTR and LUM signals and then converts these signals into a measurement or Canary Number (CN). These pulses of laser light can detect caries lesions up to 5 mm below the tooth surface [ 39 , 40 , 41 ]. As a caries lesion increases in volume there is a corresponding change in the PTR and LUM signals [ 40 ].…”