The TOPological Sub-Strutural Molecular Design (TOPS-MODE) approach has been introduced for the study of mutagenic properties. The mutagenicity of 23 dental monomers was studied with this approach obtaining a good quantitative structure-toxicity model. For the comparison were involved four different weights in the diagonal entries of the bond matrix for selecting the best TOPS-MODE model. TOPS-MODE was used to derive the contribution of different fragments to the toxicity of studied compounds. (C) 2004 Published by Elsevier Ltd.