The isolation of fungi from laboratory dental pumice

Samples of used dental laboratory pumice from the two dental laboratories were cultured for the isolation of fungi. The resulting supernatant fluid from sedimentation of each pumice sample after suspension in sterile saline was serially diluted and plated onto Sabouraud agar. After incubation, fungal colonies observed were enumerated, isolated, and identified. The mean number of fungal colonies recovered from 10 pumice samples in laboratories I and II was 51.0 X 10(2) and 22.6 X 10(2), respectively. In both laboratories the predominant fungi recovered were Aspergillus niger and Fusarium sp. Other fungi recovered included Cephalosporium and Penicillium species and A. flavus. Many of these organisms have been involved in human disease. It is suggested that the presence of fungi in used dental laboratory pumice presents an unhygienic condition in the dental laboratory and may place dental laboratory technicians and denture patients at increased risk of fungal sensitization and disease.