University of Kashan Journal of Nanostructures 2251-7871 14 3 2024 07 01 The Impact of ND: YAG Laser and PLGA/ Xylitol Nanoparticles on Dental Enamel (in Vitro Study ) 980 992 114313 10.22052/JNS.2024.03.026 EN Ghada Abdul Salam Ibrahim Preventive Dentistry Department, College of Dentistry, University of Baghdad, Baghdad, Iraq Eaman Ali AL-Rubaee Department of Basic Science, College of Dentistry, University of Baghdad, Baghdad, Iraq Maha Jamal Abbas Preventive Dentistry Department, College of Dentistry, University of Baghdad, Baghdad, Iraq Journal Article 2024 04 26 Dental caries is a prevalent chronic infectious illness caused by tooth-adherent cariogenic bacteria. Demineralization by acid invasion is the fundamental principle of a dental caries lesion. One of the possibly effective preventative methods against dental caries is laser and nanotechnology. The objective of this study is to determine the impact of the Nd:YAG laser and PLGA/Xylitol nanoparticles on the microhardness of dental enamel and the morphological change in the dental enamel ultrastructure. In this study, 55 maxillary first premolars were divided into five groups: four study groups and one control group, each with 11 teeth; 10 teeth were examined for microhardness, while one tooth was subjected to SEM. A circular window was positioned on the buccal surface of each tooth. Following a PH cycling technique to activate caries lesions on the tooth enamel, lasing was performed using predetermined parameters. The PLGA/Xylitol nanoparticle concentration was adjusted to 5%. The microhardness and morphological change were measured quantitatively using micro Vickers and SEM, respectively, at 3 stages: sound, demineralization, and treatment. Enamel microhardness values decreased highly significantly after the demineralization stage compared to the sound stage for all groups. After application of various agents, the microhardness values of all treated groups, excluding the control, increased highly significantly in comparison to the demineralization stage. The nanoparticles+laser treated group exhibited a sharp increase in microhardness values. An SEM showed an ultrastructural change that began with the loss of typical enamel structure after demineralization. The application of nanoparticles, nanoparticles + laser, and laser + nanoparticles caused the majority of surface defects to be repaired. The enamel surface treated with Nd:YAG laser and PLGA/Xylitol nanoparticles yielded favorable results in terms of microhardness and SEM analysis, suggesting that this therapy could be recommended as a means of preventing dental caries. https://jns.kashanu.ac.ir/article_114313_91a65d76b3724d3627d614bb0bc8b9f5.pdf