In vitro investigation: the impact of MI varnish and fractional CO₂ laser on demineralized enamel surfaces

To assess the therapeutic efficacy of fractional CO₂ laser and MI varnish alone and their combined effects in two cases ( CO₂ Laser before and after the application of MI varnish). Method: 60 enamel samples were prepared, and then the samples were passed through the pH cycling process to induce a demineralized enamel surface. The samples were categorized into five groups: control, CO₂ laser, MI varnish, CO₂ laser with MI varnish, and MI varnish with CO₂ laser. Surface alterations were evaluated using the Vickers microhardness assessment, surface roughness, and the Scanning Electron Microscope (SEM) combined with the Energy-Dispersive X-ray Spectroscopy (SEM-EDX).Results: All of the microhardness results were diminished after the demineralization process, and then subsequently, the different treatments enhanced the demineralized enamel surface with no notable distinction among the treatment groups. The surface roughness data showed improved surface roughness in the CO₂ laser-containing groups. The surface morphology and mineral weight were enhanced after the treatments.All treatment groups were effective in enhancing the microhardness, roughness, and surface morphology in comparison to the control group, preferring the simultaneous application of CO₂ laser and MI varnish in both instances (similar results).