 WHO estimates dental caries prevalence to be over 90 adults worldwide. When tooth substance loss due to the decayed tissue is small, a filling is done by the dentist directly. When the substance loss is important, dentists often treat it with a crown, which presents the disadvantage of further mutilating the tooth. An intermediate technique consists in manufacturing an inlay or an onlay: these restorations become more and more common since they are a minimally invasive solution in such cases. Inlays and onlays can be made of metal, ceramic or composite. Patients tend to refuse metallic restorations, so that dentists generally have to choose between composite and ceramic. Composite wears whereas ceramics fracture. Published in vitro studies provide possible answers to which material is most effective but very few clinical studies have been conducted to confirm them. Materials choice for inlay manufacturing is thus more country-based than evidence-based Most french dentists choose composite while US dentists prefer ceramics for example. The main objective of this trial is to compare the clinical performance of ceramic and composite inlaysonlays. Other objectives include looking for the prognostic factors of these restorations and validating the criteria proposed by the World Dental Federation FDI to evaluate dental restorations. 