Nanomechanical properties for tooth enamel around orthodontic brackets after immersion in demineralization solution (8% Methocel MC gel + 0.1M lactic acid) for 96 hours were measured after the brackets were bonded with fluoride-releasing adhesives [Beauty Ortho Bond, Shofu (BO) or Fuji Ortho LC Automix, GC (FO)] and non-fluoride-releasing adhesive [Transbond Plus self-etching system, 3M Unitek (TB)]. Buccal surfaces of teeth from the cusp to the cervix were coated with 1.5 mm width of acid-resistance nail varnish, and these regions were used as control. After immersion, the specimens were encapsulated in epoxy resin and cut horizontally with a slow-speed water-cooled diamond saw; then their surfaces were polished. Nanoindentation testing was carried out at 25°C (ENT-1100a, Elionix) using 10 mN load placed at 1–46 µm depth from the surface. Mean nanohardness and elastic modulus were compared statistically (ANOVA, Tukey). At distances of 50 µm and 100 µm from the bracket edge of specimens bonded with TB, nanohardness and elastic modulus were decreased in regions from the surface to 16 µm depth, indicating that these regions of enamel may be demineralized. For specimens bonded with BO, the nanohardness and elastic modulus were decreased from the surface to 6 µm and 11µm depths in regions 50 µm and 100 µm from the bracket edge, respectively. Specimens bonded with FO showed similar nanohardness and elastic modulus to control region. Results show that nanoindentation is a useful method for investigating mechanical properties in small regions of enamel and these properties should be relevant to demineralization.