Dental caries has been a highly prevalent and costly disease in the world, representing the most common infectious disease in the paediatric population. The disease is also increasingly isolated in specific teeth and tooth morphology types in both primary and mixed dentitions, with pits and fissures being the predominant decayed sites. Materials such as glassionomers, resin ionomers, resin ionomer products, and improved resin-based composite systems have been developed which are havingprofound impact on the restoration of primary teeth, particularly the treatment of proximal and anterior caries. The principal advantage of these new materials is that they require less retention form, and this is particularly important in primary teeth to conserve the relatively thin enamel that could help prevent subsequent cariesinvasion of dentin.