engleski

Characteristics of metal allergy in orthodontic patients

AIM: Metal allergy related to orthodontics was analysed. MATERIALS AND METHOD: Cross-sectional study included 239 subjects undergoing orthodontic treatment with a fixed orthodontic appliance aged 11-45 years (median 18 ; 51% adolescents ; 67% females). Epicutaneous patch test was performed on average 4 months after bonding the appliance to analyze allergy on nickel sulfate, titanium, titanium dioxide, titanium oxalate and titanium nitride. Intraoral changes were assessed for confirmation of the allergy status (gingival hyperplasia, exfoliative cheilits or glossitis) and questionnaire on potential symptoms, allergies and previous exposure were used. Gustatory and olfactory testing was used to analyze chemosensory function. In subjects with persisting gingival enlargement after initial periodontal therapy, an external gingivectomy was performed. Histopathological and immunohistochemical analysis of gingiva was performed including antibodies against Langerhans cells, T, B, Th1 and cytotoxic lymphoctyes, plasma cells and macrophages. RESULTS: Metal allergy was confirmed in 11% of subjects (positive patch test+intraoral finding), 5% had positive test but without intraoral signs, 39% had signs but negative test while 45% were negative without signs. Univariate analyzes showed that subjects with confirmed metal allergy report history of contact hypersensitivity on metals, jewelery or cosmetics, other allergies, weakened sense of taste, swelling in the mouth and eye tearing (p≤0.049). In multiple regression analysis, when controlling for all those medical history variables as well as age and gender, significant predictors of metal allergy were only imitation jewelry contact hypersensitivity (OR=6.0 ; 95% CI 1.8-20.6 ; p=0.004) and eye tearing (OR=5.8 ; 95% CI 1.6-21.7 ; p=0.008). Allergic patients had more impairment of the sense of taste, specifically bitter and sour (p≤0.006). Gingiva of allergic patients demostrated more epithelial inflammation, less diffuse multifocal inflammatory infiltrate and fewer macrophages (p≤0.049). There was also a tendency of an increased number of Langerhans cells and decreased number of T helper and cytotoxic lymphocytes, and plasma cells. CONCLUSION: Previous contact hypersensitivity to metals, eye tearing and impaired taste seem to indicate metal allergy in orthodontic patients. Sensitized gingiva showed some characteristics of late hypersensitivity immune reactions, but also dominant irritative effect.

immunohistochemistry ; allergy ; orthodontic appliance ; titanium ; nickel.

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