Influence of abrasive solutions on direct restorative composites wear

Tribological characterization of dental restorative materials is very hard because it is difficult to reproduce the actual test conditions which occur in the mouth. Despite the wide variety of wear test equipment, there are no wear test standards. The guide provided by the International Organization for Standardization (ISO), entitled "Dental materials-guidance on testing of wear-part 2: Wear by two-and/or three body contact, Technical Specification 14569-2 number 2001 focuses only on a technical description of the procedures. This standard doesn't evaluate or demonstrate any of the advantages or disadvantages of the existing tests or their procedures. This work is focused on the evaluation of the effect of abrasion solution. Three abrasive of the most common used were select. Test condition such as load and number of cycles were established, in order to attain specific wear rates similar to the ones in the mouth. From a soft organic abrasive to more severe abrasive several solutions were tested. Wear analyses was done using two distinct approaches; a classical and an energetic. A glass sphere against a flat direct restorative composite surface on a reciprocating sliding contact were selected for the evaluation, initial conditions were set based on previous studies which provided decisive information for the selection of adequate laboratorial parameters. It was found that the wear evolution of the composite and antagonist materials depends directly on the abrasive solution and test conditions used. It was necessary to fix a standard parameter to compare abrasive solutions, wear rate (mm(3)/cycle) of natural teeth. The use of each abrasive solution can be made depending on the purpose of the study, i.e., if it is comparative performance of a particular material or if you want to simulate more closely what goes into the mouth. If the purpose of the study is to compare performance of particular materials (more severe abrasive solution) or if we want to simulate more closely what happens in the mouth (mild abrasive solution). A morphological and wear mechanisms analysis were done using SEM, this allowed to compare qualitatively the effect of abrasive solution on the material pair.