A method for monitoring enamel erosion using laser irradiated surfaces and optical coherence tomography

Abstract

Introduction Since optical coherence tomography (OCT) is well suited for measuring small dimensional changes on tooth surfaces, OCT has great potential for monitoring tooth erosion. Previous studies have shown that enamel areas ablated by a carbon dioxide laser manifested lower rates of erosion compared to the non-ablated areas. The purpose of this study was to develop a model to monitor erosion in vitro that could potentially be used in vivo. Methods Thirteen bovine enamel blocks were used in this in vitro study. Each 10 mm × 2 mm block was partitioned into five regions, the central region was unprotected, the adjacent windows were irradiated by a CO2 laser operating at 9.3 μm with a fluence of 2.4J/cm2, and the outermost windows were coated with acid resistant varnish. The samples were exposed to a pH cycling regimen that caused both erosion and subsurface demineralization for 2, 4 and 6 days. The surfaces were scanned using a time-domain polarization sensitive optical coherence tomography (PS-OCT) system and the degree of surface loss (erosion) and the integrated reflectivity with lesion depth was calculated for each window. Results There was a large and significant reduction in the depth of surface loss (erosion) and the severity of demineralization in the areas irradiated by the laser. Conclusion Irradiation of the enamel surface with a pulsed carbon dioxide laser at sub-ablative intensities results in significant inhibition of erosion and demineralization under the acid challenge employed in this study. In addition, these results suggest that it may be feasible to modify regions of the enamel surface using the laser to serve as reference marks to monitor the rate of erosion in vivo.

CO2 laser emission modes to control enamel erosion

“…The use of highly concentrated compounds of fluoride (Ganss et al, ; Lagerweij et al, ; Schlueter et al, ) and laser irradiation CO 2 (Chan et al, ; Esteves‐Oliveira et al, ; Lepri et al, ; Ramalho et al, ; Ramos Oliveira et al, ; Steiner‐Oliveira et al, ; Wiegand et al, ) have been investigated as preventive therapies against dental erosion.…”

“…CO 2 laser irradiation can be increased the acid resistance of enamel (Chan et al, ; Schmidlin et al, ) and reduce the enamel surface loss (Ramalho et al, ; Ramos Oliveira et al, ) by chemical and/or structural changes of the dental enamel. The most accepted theory about the action mechanism of laser irradiation on the tissue is related to temperature increase caused by irradiation, which can promote changes in water content and carbonate (Fowler and Kuroda, ) and denaturation part of the organic matrix (Hsu et al, ).…”

Optical-fiber-based laser-induced breakdown spectroscopy for detection of early caries

“…However, these lesions underneath enamel usually show the appearance of early caries. Therefore, this method can be a cue for follow-up detailed examinations based on other methods such as optical coherence tomography 35,36 and x-ray inspection.…”

Quantitative Swept-Source Optical Coherence Tomography of Early Enamel Erosion in vivo

“…In addition, the impact of clinical variables influencing in vivo enamel OCT imaging is not clearly understood. Thus, quantitative detection of early enamel erosion using OCT in vivo is complicated by multiple interacting surface phenomena which are poorly defined, including the composition and function of the acquired enamel pellicle [Hannig et al, 2003;Carpenter et al, 2014;Moazzez et al, 2014], the degree of hydration of the dental hard tissue during imaging [Nazari et al, 2013;Chan et al, 2014], and the micro-textural changes of the curved enamel surface in vivo during erosion [Austin et al, 2015[Austin et al, , 2016. Therefore, carefully controlled clinical studies simulating early erosion are required to elucidate the optimal analytical techniques for imaging early erosive changes.…”