A cluster of idiopathic pulmonary fibrosis cases in the US has led the Centers for Disease Control and Prevention to issue a warning.

The warning comes after nine out of 894 patients treated for IPF at a tertiary care centre in Virgina were identified as dental personnel, including eight dentists and one dental technician.

According to the CDC this rate of 1 percent was about 23 times higher than in the general population. All patients were male and were treated during 2000–2015.

“This is the first known described cluster of IPF occurring among dental personnel. Although no clear etiology exists for this cluster, it is possible that occupational exposures contributed to the development of IPF,” the CDC said in its Morbidity and Morality weekly report.

The report noted that dentists and other dental personnel experienced unique occupational exposures, including exposure to infectious organisms, dusts, gases, and fumes.

“Further investigation of the risk for dental personnel and IPF is warranted to develop strategies for prevention of potentially harmful exposures” it concluded.