Iran Occupational Health

  Background and aims

  Methyl Methacrylate (MMA) which is known as a long, skin and eye  irritant is the most common form of acrylic plastic used in dental laboratories. The aims of this study were to evaluate dental technicians, exposure to MMAand to assess their health with a focus  on respiratory and dermal symptoms.

  Methods

  Exposure to MMA, total dust and health symptoms were investigated in 20 dental  laboratories located in Tehran, Iran. Time weighted average (TWA) of MMA and peak  concentrations were determined , using XAD-2 tubes followed by GC-ID analysis. Total dust  were evaluated gravimetrically. Health symptoms were asked using a questionnaire.

  Results

  The TWAfor technicians with direct and indirect exposure to MMAwere 327.28 + 79.42  and 282.9 + 41.84 mg/m3, respectively. Peak concentration of MMA for those technicians were  337.0 + 36.81 and 328.88 + 45.40 mg/m3, respectively. There were no significant differences  between TWAof MMAand peak concentration in different weakly workdays low ever, within -  day variations were observed (P<0.05). TWAof MMA and peak concentration correlation with  the laboratory volume were 0.61- 0.65, Dust exposure of technicians was 2.35 + 2.70 mg/m3. Cough and Skin dryness were the common health symptoms. Smoking and asbestos exposure history were factors influencing cough prevalence (P<0.005).

  Conclusion

  It is concluded that the current short - Term Exposure Limit (STEL) is not low enough to protect technicians against the adverse effects caused by MMA.