Occupational respiratory hypersensitivity in dental personnel

Objective: The aim was to study the causes of respiratory hypersensitivity in dental personnel based on the statistics of the Finnish Register of Occupational Diseases (FROD; 1975–1998) and the patient material of the Finnish Institute of Occupational Health (FIOH; 1990–1998). Methods: Details about the cases of respiratory hypersensitivity were compiled from the FROD. The occupational rhinitis diagnoses studied at the FIOH were based on work-related symptoms and a change in the status of the nasal mucosa during challenge testing; and the diagnosis of occupational asthma based on reactions in challenge testing, or on IgE positivity and peak flow monitoring at work and during days off. Results: A total of 64 cases of occupational respiratory diseases (ORDs) was diagnosed in dental personnel during 1975 to1998 according to the FROD; two cases in 1975 to 1989, and 62 in 1990 to 1998. Twenty-eight cases were of occupational asthma (18 caused by methacrylates), 28 occupational rhinitis (six caused by methacrylates), seven allergic alveolitis and one organic dust toxic syndrome (ODTS). The non-acrylate-material diagnosed in 1990–1998 at the FIOH comprised three cases of asthma and one of rhinitis caused by chloramine-T (sodium-N-chlorine-p-toluene sulphonamide); as well as one case of asthma, seven cases of rhinitis, and two cases of combined rhinitis and conjunctivitis caused by natural rubber latex (NRL). Furthermore, one case of occupational rhinitis caused by Nobetec containing colophony was diagnosed. The incidence rate (IR) of ORD increased from 0 in 1988 to a peak of 105.1 new cases per100,000 working years in 1995. During the last observation year, i.e. 1998, the IR was 55 new cases per 100,000 workers. The IR in dental personnel was lower than in the whole working population in Finland up until 1992, but since then has been greater than in the whole population, peaking in 1995 when the IR of dental personnel was 2.55 times greater than in the whole population. Conclusion: The present study shows the increasing frequency of respiratory hypersensitivity among dental personnel. Besides methacrylates, important causes of respiratory hypersensitivity are NRL and chloramine-T.