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OBJECTIVE The purpose of this study was to evaluate the effects of laser and acid etching on the mineral content and photon interaction parameters of dental enamel in human teeth. BACKGROUND DATA The composition of dental enamel may vary, especially at the surface, depending on the reactions that occur during dental treatment. MATERIALS AND METHODS Forty maxillary premolars were divided randomly into 2 groups of 20 teeth. In the first group, half of teeth crowns were etched by using 37% phosphoric acid; in the second group, half of teeth crowns were etched by using an erbium:yttrium-aluminum-garnet (Er:YAG) laser. The remaining half crowns in each group were used as untreated controls. We characterized the calcium (Ca), phosphorus (P), magnesium (Mg), sodium (Na), and potassium (K) contents in each specimen by using wavelength dispersive X-ray fluorescence spectrometry. The total atomic cross-section ([Formula: see text]), effective atomic number ([Formula: see text]), and electron density (Ne) of the tooth samples were determined at photon energies of 22.1, 25, 59.5, and 88 keV by using a narrow beam transmission method. Data were analyzed statistically by using the Mann-Whitney U test. RESULTS The mineral contents after Er:YAG laser and phosphoric acid etching did not differ significantly (p > 0.05), and no significant variation in [Formula: see text], [Formula: see text], or Ne was observed. CONCLUSIONS Therefore, we conclude that the Er:YAG laser and phosphoric acid systems used in this study did not affect mineral composition or photon interaction parameters of dental enamel.