The U.S. Centers for Disease Control and Prevention have identified a cluster of dentists [cnn.com] that all contracted idiopathic pulmonary fibrosis [wikipedia.org] and were treated at a particular Virginia care center:
A cluster of cases of a progressive lung disease occurred among dentists and other dental workers treated at one Virginia care center, according to Thursday's Morbidity and Mortality Weekly Report [cdc.gov] [open, DOI: 10.15585/mmwr.mm6709a2] [DX [doi.org]] from the US Centers for Disease Control and Prevention.
Of nine patients, referred to as a cluster, seven died during the reported 16-year period. The disease, called idiopathic pulmonary fibrosis [nih.gov], is a chronic, progressive lung disease with a poor prognosis. The cause is unknown.
[...] In this case, among 894 patients treated for idiopathic pulmonary fibrosis at the Virginia hospital, nine patients -- or 1% -- were identified as dentists or dental technicians. This number "was about 23 times higher than expected," Nett said.
The clustering may be explained by occupational exposure to an unknown hazard.
Also at Newsweek [newsweek.com].