Assessment of the preventive effects of Nd:YAG laser associated with fluoride on enamel caries using optical coherence tomography and FTIR spectroscopy

Author(s)

Dias-Moraes, Marcia Cristina ^[1] ; Castro, Pedro Arthur Augusto ^[1] ; Pereira, Daisa Lima ^[1] ; Ana, Patricia Aparecida ^[2] ; Freitas, Anderson Zanardi ^[1] ; Zezell, Denise Maria ^[1]

Affiliation

^[1] CNEN SP, IPEN, Inst Pesquisas Energet & Nucl, Ctr Lasers Applicat, Sao Paulo, SP - Brazil

^[2] Univ Fed ABC, Ctr Engn Modelling & Appl Social Sci, Sao Bernardo Do Campo, SP - Brazil

• Document type: Journal article
• Source: PLoS One; v. 16, n. 7 JUL 7 2021.
• Web of Science Citations: 0

Abstract

Objective This in vitro study characterized and monitored, by Optical Coherence Tomography (OCT) and Fourier Transformed Infrared Spectroscopy (FTIR), the effects of the association of acidulated phosphate fluoride gel (APF-gel) and Nd:YAG (neodymiun:yttrium-aluminum-garnet) laser, as sequencial treatments, in the prevention of incipient enamel caries lesions. Methods 120 human enamel samples were randomized into 3 groups (n = 40): APF-gel (1.23% F-, 4 min.); Laser+APF (Nd:YAG laser irradiation-0.6W, 84.9J/cm(2), 10Hz, followed by APF-gel); and APF+Laser (APF-gel followed by laser irradiation). The samples were subjected to a 15-day pH-cycling, evaluated by OCT (quantification of optical attenuation coefficient-OAC) and FTIR (analysis of carbonate and phosphate content) before treatments, after treatments, and on the 5(th), 10(th) and 15(th) days of pH-cycling. The statistical analysis was performed (alpha = 5%). Results The Optical Attenuation Coefficient (OAC) assessed by OCT increases with the progression of demineralization, and the Laser+APF presented the highest values of OAC in 10(th) and 15(th) days of pH-cycling. Nd:YAG decreased the carbonate content after treatment regardless of the application order of the APF-gel, while APF-gel did not interfere in the composition of enamel. The carbonate content was also changed in the first 5 days of the pH-cycling in all groups. Conclusion Nd:YAG laser irradiation before or after the application of APF-gel did not influence the appearance of incipient caries lesions, showing no synergistic effect. Regardless of the application order of the APF-gel, laser irradiation reduces the carbonate content of the enamel, which also changes during the demineralization process. However, irradiation before the application of APF-gel increased the speed of progression of the lesions, which positively impacts public health as it can prevent caries disease, even in high risk individuals. OCT and FTIR are suitable for assessing this effect. (AU)

• FAPESP's process: 17/50332-0 - Scientific, technological and infrastructure qualification in radiopharmaceuticals, radiation and entrepreneurship for health purposes (PDIp)
• Grantee: Marcelo Linardi
• Support Opportunities: Research Grants - State Research Institutes Modernization Program
• FAPESP's process: 05/51689-2 - Optics and Photonics Research Center at UNICAMP
• Grantee: Hugo Luis Fragnito
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC