The CDC has identified a cluster of lung disease cases among dentists and dental workers who were treated at a Virginia care center. All were diagnosed with idiopathic pulmonary fibrosis (IPF), “a chronic, progressive lung disease of unknown cause and associated with a poor prognosis.”

Seven of the nine patients have died. According to the CDC, the estimated survival rate after diagnosis is only 3–5 years. “Although IPF has been associated with certain occupations, no published data exist regarding IPF in dentists” so the CDC is anxious to find out the cause:

 A questionnaire was administered to one of the living patients, who reported polishing dental appliances and preparing amalgams and impressions without respiratory protection. Substances used during these tasks contained silica, polyvinyl siloxane, alginate, and other compounds with known or potential respiratory toxicity.

Although the cause of IPF is unknown, the CDC says that “exposures that have been suggested as contributing factors include viral infections, cigarette smoking, and occupations where exposure to dust, wood dust, and metal dust are common.”