The aim of this study was to evaluate knowledge, attitudes and practices (KAP) of Moroccan dentists about allergy to Nickel (Ni) during orthodontic treatment. Dentists of two Moroccan cities (n = 553) were contacted and a questionnaire was distributed to those who have certified of partial or exclusive practice of orthodontics (N = 202). They were asked to specify the adverse reactions observed and the alloys frequently used. KAP about etiology, prevention and therapeutic management of allergic patients were also addressed. Twenty-two percent of the dentists have reported at least one allergic patient reaction with more implication of fixed appliances. Eleven percent of adverse effects locations reported were mucosal area and facial skin near contact area and less than 5% was systemic eruption outside contact site. Only 34% of the respondents knew the Nickel allergy etiology. Nickel-containing orthodontic alloys are generally used even in patient with suspected nickel allergy. It is very important to minimize corrosion factors and use nickel-free appliances in clinical practice.
