Effect of CO2 laser (9.3 mu m) irradiation and AmF/NaF/SnCl2 solution in prevention and control of erosive tooth wear, an in-situ study

Objectives: The cross-over in-situ study aimed to evaluate the effect of CO2 laser (9.3 mu m) irradiation, in combination with an AmF/NaF/SnCl2 rinse on prevention and control of Erosive Tooth Wear (ETW) in human enamel. Materials and Methods: Two different settings were tested with, 1) as ETW-prevention (starting from sound tooth surfaces) (Setting-1), and 2) as ETW-control (substrates presented at start an artificial erosive lesion) (Setting-2). Additionally, in in one subset samples were exposed to AmF/NaF/SnCl2 solution (Phase I) while in the other no exposure to the Fluoridetin rinse occurred (Phase). 192 samples of human enamel (3x3x1mm) were randomly divided into 4 experimental groups: (C) without treatment (negative control); (F) AmF/NaF/SnCl2 solution (positive control); (L) CO2 laser irradiation; (L+F) CO2 laser+AmF/NaF/SnCl2 solution. 12 volunteers wearing removable devices participated in the study, carrying 8 samples per device. The erosive challenges (4x5min/day) occurred ex-vivo. The surface loss over time was measured using an optical profilometer (n=12 per group). Setting-1 data were analyzed by one-way ANOVA and Setting-2 data by two-way repeated measures ANOVA, both with Tukey post-hoc tests (a=5%). Results: Setting-1: groups L (4.59 +/- 2.95 mu m) and L+F (1.58 +/- 1.24 mu m) showed significantly less surface loss in preventing ETW than groups C and F. Setting-2: in controlling the progression of ETW, L+F was the only group with no significant surface loss between initial erosive lesion (3.65 +/- 0.16 mu m) and after erosive challenge (4.99 +/- 1.17 mu m). Conclusions: CO2 9.3 mu m laser application prevented and controlled ETW progression in human enamel, with greater efficiency when combined with AmF/NaF/SnCl2 solution application.*