Effects of methyl methacrylate monomer vapors on respiration and circulation in unanesthetized rats

Impact of fabrication procedures on residual monomer elution of conventional polymethyl methacrylate (PMMA)-a measurement approach by UV/Vis spectrophotometry

OBJECTIVES

To analyse the residual monomer (MMA) elution of polymethyl methacrylate (PMMA) in distilled water after diverse fabrication methods and aging procedures.

MATERIALS AND METHODS

PMMA specimens (N = 192, PalaXpress; Kulzer, Hanau, Germany) were manufactured (pouring, n = 96/injection, n = 96) and polymerized in water (55°C) without pressure (n = 48) and with 2 bar pressure (n = 48). Specimens were grinded (n = 24) or polished (n = 24) and aged for 12 h in distilled water/37°C (n = 12) or at air/20°C (n = 12) and stored afterwards in distilled water at 37°C. MMA elution was evaluated after 1, 2, 3, 4, 5, 6, 7, 10, 15 days (UV/Vis spectrophotometry). Data were analysed with Kolmogorov-Smirnov, Mann-Whitney-U and Cohen-d test using SPSS (α < 0.5).

RESULTS

The pouring procedure resulted in significantly higher MMA elution than the injection procedure up to 5 days. Polymerization with a pressure of 2 bar reduced the MMA elution significantly for poured specimens. Polishing reduced the MMA elution in comparison to grinding.

CONCLUSIONS

The fabrication procedure (pouring/injection) showed the strongest correlation to the MMA elution (r = 0.500), followed by polishing (r = 0.243), the pressure during polymerization (r = 0.109) and the storage medium (r = 0.053).

CLINICAL RELEVANCE

Higher MMA elution may increase the risk of chemical irritations, allergic reactions and hypersensitivities of the oral mucosa. Technicians and dentists should be aware about the elution differences dependent on the fabrication procedure.

Inhalation study of polymethyl methacrylate following radiologist exposure during percutaneous vertebroplasty

OBJECTIVE

To assess the atmospheric concentrations of methyl methacrylate (MMA) vapors during percutaneous vertebroplasty for the interventional radiologist and the other operating room staff.

MATERIALS AND METHODS

During percutaneous vertebroplasty, a polymethyl methacrylate (PMMA) mixture (about 20 mL) was prepared with a mixing system in a normally ventilated room. Atmospheric concentrations of MMA vapors were measured by a gas absorbent badge for individual exposure (GABIE) passive sampler attached to the surgical gowns of the interventional radiologist and the other operating room staff over a period of 460 min. Active sampling was performed over 15 min with an individual pump placed near the breathing zone of the radiologist. MMA vapor concentrations were then measured using gas chromatography and activated charcoal tubes.

RESULTS

Mean MMA vapor concentrations measured by the GABIEs over the period of 460 min were 0.51 parts per million (ppm) for the radiologist and 0.22 ppm for the other operating room staff. The emission peaks measured by using charcoal tubes over 15 min were 3.7 ppm.

CONCLUSION

MMA vapor concentrations during percutaneous vertebroplasty were well below the recommended maximum exposure of 100 ppm over the course of an 8-h workday.

The effects of methyl methacrylate on nasal cavity, lung, and antioxidant system (an experimental inhalation study)

Methyl methacrylate (MMA) is a monomer, commonly used in neurosurgery, orthopedic surgery, and in dental clinics. The adverse effects of this monomer are well described in the literature. This study was designed to evaluate the effects of MMA on nasal cavity, lung, and antioxidant status. For this purpose, two experimental groups of rats were exposed to MMA (at 1,000 ppm, 6 h/day, 5 days/week for 4 weeks) by inhalation under poor (group A, n = 12) and normal ventilation (group B, n = 11) conditions. A control group (group C, n = 10) received normal air. Degeneration of olfactory epithelium, bronchopneumonia, interstitial pneumonia, hemorrhage, atelectasis, edema, emphysema, and bronchial epithelial hyperplasia were observed in groups A and B. Emphysema was the most common lesion. Bronchopneumonia with abscesses was only observed in group A. Glutathione levels were significantly decreased and malondialdehyde levels were significantly increased in group A. No significant difference was observed in superoxide dismutase levels between the groups. The data presented indicate that before using MMA, adequate protection systems should be in place to prevent occupationally related MMA respiratory-tract injuries.