During the past two decades the incidence of allergies against dental materials has been rising. The most common allergens are nickel, mercury, benzoxyl-peroxide, formaldehyde, MMA, HEMA, EGDMA and TEGDMA. Contact allergy develops in predisposed individuals as a consequence of environmental exposures to allergens. Although the relatively high frequency of contact allergies in children is well documented, its importance during orthodontic treatments is still often underestimated. The most common metal to cause dental allergic reactions is nickel. Nickel-containing metal alloys, such as nickel-titanium, are widely used in orthodontics because of their favorable physical properties. Coated wires (epoxi coating, teflon, etc.) are not only more aesthetic, but can play a role in the orthodontic treatment of patients with nickel allergy. In our case report we present two patients with nickel allergy, and their treatment with alternative orthodontic appliances. During the orthodontic treatment our patients did not have any objective or subjective allergy-related symptoms.