No abstract

Pneumoconiosis in dental laboratory workers has been associated with exposure to metal alloys and silica used in the manufacturing of dental prosthetics. In this report, we describe a 27-yr-old dental student who was found to have bilateral basal pulmonary interstitial infiltrates and nodules on a chest roentgenogram after a brief episode of upper respiratory infection. An open lung biopsy revealed interstitial pneumonitis with an abundance of vacuolated macrophages in the alveolar spaces. Ultrastructural analysis showed in the alveolar and interstitial spaces the accumulation of macrophages laden with electron-lucent bodies resembling plastic beads. An inhalation exposure history, taken subsequent to these findings, revealed exposure to high levels of acrylic plastic in a dental school laboratory. Removal from the site of exposure has resulted in the gradual resolution of the roentgenographic abnormalities.

Acrylic polymers are increasingly used in dental laboratories for preparation of prostheses. In the past, dental technicians have developed pneumoconiosis due to inhalation of silica dust or heavy metal alloys, but to our knowledge, no other cases of lung disease due to inhalation of acrylic dust have been previously reported.The patient, a dental student, was admitted to the Hospital of the University of Pennsylvania for evaluation of persistent bilateral interstitial infiltrates and cough. An open lung biopsy was performed to determine the cause of the infiltrate. The biopsy specimen revealed interstitial lymphocytic infiltrates and intra-alveolar accumulation of “foamy” macrophages (Fig. 1) suggesting lipoid pneumonia. Since he did not use medications containing mineral oil or had obstructive lesions of the airways, electron microscopy examination of the biopsy specimen was performed. Transmission electron microscopy (TEM) revealed accumulation of macrophages in the alveolar space and interstitium, containing numerous electron-lucent vacuoles of varying size (Fig. 2).