MORPHOLOGICAL-CHANGES IN CULTURED HUMAN PERIODONTAL-LIGAMENT CELLS EXPOSED TO DENTAL MATERIALS

The cytotoxicity of a range of dental restorative cements was assessed by continuous observation of cultures with inverted microscopy and by light microscopic study of fixed preparations, using an in vitro mode l with cultured test cells derived from human periodontal ligament. Th e sequential morphological changes observed over a seven day period sh owed different degrees of cell loss and patterns of injury in response to different restorative materials, reflecting primarily either nucle ar or cytoplasmic damage. Attempts at recovery were frequently identif ied as the culture period was extended acid were characterized by reco lonization of denuded areas of the culture well. It was concluded that differing dental cements damage cells through a variety of mechanisms and that the test cells exhibit differing degrees of susceptibility t o injury. Assays based on short-term cultures may overestimate cytotox icity by not allowing for cell recovery from reversible injury or repo pulation of monolayers by proliferation of resistant cells.