The topological sub-structural molecular design (TOPS-MODE) approach has been introduced for the study of mutagenic properties. The mutagenicity of 16 dental monomers was studied with this approach, obtaining a good quantitative structure-toxicity model. For comparison, four different weights were involved 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 Elsevier Ltd. All rights reserved.