Influence of a pulsed CO2 laser operating at 9.4  μm on the surface morphology, reflectivity, and acid resistance of dental enamel below the threshold for melting

Jin Wan Kim; Raymond Lee; Kenneth H. Chan; Jamison  M. Jew; Daniel Fried

doi:10.1117/1.JBO.22.2.028001

1 February 2017 Influence of a pulsed CO₂ laser operating at 9.4 μm on the surface morphology, reflectivity, and acid resistance of dental enamel below the threshold for melting

Jin Wan Kim, Raymond Lee, Kenneth H. Chan, Jamison M. Jew, Daniel Fried

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Funded by: NIH/NIDCR

Journal of Biomedical Optics, Vol. 22, Issue 2, 028001 (February 2017). https://doi.org/10.1117/1.JBO.22.2.028001

Abstract

Below the threshold for laser ablation, the mineral phase of enamel is converted into a purer phase hydroxyapatite with increased acid resistance. Studies suggest the possibility of achieving the conversion without visible surface alteration. In this study, changes in the surface morphology, reflectivity, and acid resistance were monitored with varying irradiation intensity. Bovine enamel specimens were irradiated using a CO2 laser operating at 9.4 μm with a Gaussian spatial beam profile—1.6 to 3.1 mm in diameter. After laser treatment, samples were subjected to demineralization to simulate the acidic intraoral conditions of dental decay. The resulting demineralization and erosion were assessed using polarization-sensitive optical coherence tomography, three-dimensional digital microscopy, and polarized light microscopy. Distinct changes in the surface morphology and the degree of inhibition were found within the laser-treated area in accordance with the laser intensity profile. Subtle visual changes were noted below the melting point for enamel that appear to correspond to thresholds for denaturation of the organic phase and thermal decomposition of the mineral phase. There was significant protection from laser irradiation in areas in which the reflectivity was not increased significantly, suggesting that aesthetically sensitive areas of the tooth can be treated for caries prevention.

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Jin Wan Kim, Raymond Lee, Kenneth H. Chan, Jamison M. Jew, and Daniel Fried "Influence of a pulsed CO₂ laser operating at 9.4 μm on the surface morphology, reflectivity, and acid resistance of dental enamel below the threshold for melting," Journal of Biomedical Optics 22(2), 028001 (1 February 2017). https://doi.org/10.1117/1.JBO.22.2.028001

Received: 16 November 2016; Accepted: 6 January 2017; Published: 1 February 2017

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