IN-VITRO ORAL-MUCOSA IRRITATION TESTING WITH HUMAN CELL-CULTURES

Cell cultures are a potentially useful model to predict in vivo oral m ucosa irritation. To this end, oral mucosa organ equivalent cultures ( OMOEC) and skin equivalent cultures (SEC), both derived from human tis sue, were evaluated for their responsiveness to test dentifrices with graded degrees of irritation potential. OMOEC and SEC were treated wit h test dentifrices and responses were evaluated by histopathology, cel l viability (MTT incorporation), and cytotoxicity [release of aspartat e aminotransferase (AST)]. Cell viability in OMOEC and SEC was reduced in a dose- and time-dependent manner in response to the test dentifri ces. Correspondingly, AST release was increased in a dose- and time-de pendent manner in response to the test dentifrices. These results demo nstrate that OMOEC and SEC systems respond linearly to graded degrees of irritation potential as represented by generic dentifrices. Such re sults in an in vitro model of oral mucosa irritation allow direct comp arison of in vitro responses with those obtained in an in vivo model, thus providing the groundwork for a tiered approach to assessment of i rritation potential of oral care products.