Respiratory morbidity in a population of French dental technicians

Our plain-English summary of Respiratory morbidity in a population of French dental technicians, by S. Radi, J.C. Dalphin, P. Manzoni, et al (Occupational and Environmental Medicine, 2002).

The study

• Authors: S. Radi, J.C. Dalphin, P. Manzoni, D. Pernet, M.P. Leboube, J.F. Viel
• Journal: Occupational and Environmental Medicine
• Published: 2002;59(6):398-404
• Cited by: 32 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Aims: To compare wage earner dental technicians with non-exposed salaried subjects for the prevalence of respiratory symptoms and function, and chest x ray abnormalities.

Methods: A total of 134 dental technicians and 131 non-exposed subjects participated. A medical and an occupational questionnaire were filled in to evaluate the prevalence of respiratory symptoms and occupational exposures. Subjects underwent respiratory tests and chest x ray examination.

Results: Mean age of the dental technicians was 36.6 years with a mean duration of dental work of 16.5 years. There was a significant risk of cough (day and night) and usual phlegm in dental technicians. Respiratory function parameters were lower in dental technicians with a significant difference between exposed and non-exposed groups for % FVC (forced vital capacity), % FEF(25) (forced mid expiratory flow), and % FEF(50). The prevalence of small opacities increased with age. Small opacities were significantly related to an exposure to asbestos in the past.

Conclusions: Our young population of dental technicians is at risk of respiratory morbidity. They should benefit from adequate technical prevention measures.

In plain English

This 1999 cross-sectional study in Bourgogne and Franche-Comté, France, compared 134 salaried dental technicians with 131 non-exposed workers matched for sex and age. Most completed questionnaires, breathing tests and chest x rays. Sixty-three technicians (47%) reported past asbestos exposure. Asbestos had been used as a film between the casting cylinder and refractory material until France banned it in 1997. Adjusted for smoking, sex, age and past asbestos exposure, technicians more often reported usual phlegm (odds ratio 7.1, 95% CI 1.4 to 36.5) and day-and-night cough (2.9, 1.1 to 8.1). Some breathing measures were also lower in technicians. Among those with readable x rays, small lung opacities (ILO profusion 1/0 or greater) were seen in 13 of 106 technicians (12.3%) and 2 of 103 controls (1.9%). This difference was not statistically significant after adjustment. Among technicians, these opacities occurred in 20.4% of 49 with past asbestos exposure and 5.4% of 55 without (odds ratio 16.7, 95% CI 1.4 to 203.9). The authors concluded that this young population is at risk of respiratory morbidity. They noted limited statistical power and a possible healthy worker effect.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Cross-sectional study comparing exposed dental technicians with non-exposed workers, using questionnaires, spirometry and chest x rays
• Who was studied: 134 wage earner dental technicians from dental laboratories in Bourgogne and Franche-Comté, France, studied in 1999, and 131 non-exposed salaried workers (mostly office workers, salespersons, accountants and secretaries) matched for age within 5 years and for sex. Mean age of technicians was 36.6 years; mean duration of dental work was 16.5 years. Not all participants completed every step: 256 filled in the medical questionnaire, 128 technicians and 121 controls had spirometry, and 213 had chest x rays, of which 209 were readable.
• Exposure: Dust and vapour from dental prosthesis manufacture (plaster, silica-containing refractory material, wax, resin, ceramic, nickel–chromium and chromium–cobalt alloys, beryllium). Past asbestos exposure was reported by 63 technicians (47%), with a mean duration of 20.7 years. Asbestos was formerly used as an isolating film between the cylinder and the refractory material and has been prohibited in France since 1997.
• Main results:
  • After adjustment for smoking, sex, age and past asbestos exposure, usual phlegm (OR 7.1, 95% CI 1.4 to 36.5) and cough day and night (OR 2.9, 95% CI 1.1 to 8.1) were more common in dental technicians than in controls
  • % FVC, % FEF25 and % FEF50 were lower in dental technicians than in controls
  • The authors reported a positive interaction between smoking and being a dental technician for all spirometric parameters
  • Among participants with readable chest x rays, small opacities with profusion 1/0 or greater were found in 13 of 106 dental technicians (12.3%) and 2 of 103 controls (1.9%). The difference was not significant after adjustment (OR 3.1, 95% CI 0.2 to 52.2, in Table 4).
  • Among dental technicians, small opacities of this profusion were found in 20.4% of the 49 with past asbestos exposure and 5.4% of the 55 without (OR 16.7, 95% CI 1.4 to 203.9)
  • Pleural involvement was found in 8 of 106 dental technicians (7.7%) and 5 of 103 controls (4.9%), adjusted OR 1.6 (95% CI 0.3 to 7.5), not statistically significant. The authors reported that large opacities and pleural involvement were not related to a particular past exposure.
  • Small opacities of profusion 1/0 or greater showed no difference by sex, age, smoking habits, or type and size of laboratory. The authors also reported no difference by exposure to silica, beryllium, metal alloys or ceramic (results not shown).
• The authors' conclusion: The authors concluded that their young population of dental technicians is at risk of respiratory morbidity and should benefit from adequate technical prevention measures. They also stated that small opacities were associated with past asbestos exposure.
• Limitations the authors state:
  • The authors described the main limitation as a relative lack of statistical power
  • A healthy worker effect is possible: technicians who left work because of respiratory disease were not included
  • Twenty-six chest x rays were missing from the dental technicians group. The authors said this could underestimate the prevalence of radiographic abnormalities, because symptoms and lung function can be normal even with pneumoconiosis.
  • Many airborne contaminants are produced in prosthesis manufacture, which the authors said makes it difficult to link pneumoconiosis to a specific agent

Topics

Medical terms in this study, explained in our Lexicon: Occupational Exposure.

Related studies

• Occupational lung diseases among dental technicians — D. Choudat (1994)
• Dental technician's pneumoconiosis. A report of two cases — P. De Vuyst, R. Vande Weyer, et al. (1986)
• Exposure to methyl methacrylate and its subjective symptoms among dental technicians, Tehran, Iran — F. Golbabaei, M. Mamdouh, et al. (2005)
• Respiratory morbidity among workers in an amosite asbestos insulation plant — W.M. Johnson, R.A. Lemen, et al. (1982)
• Evaluation of respiratory effects in miners and millers exposed to talc free of asbestos and silica — D.H. Wegman, J.M. Peters, et al. (1982)
• Longitudinal pattern of reported respiratory symptoms and accelerated ventilatory loss in asbestos-exposed workers — C.A. Brodkin, S. Barnhart, et al. (1996)

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