Preformed Pediatric Crown Zirconia Versus Preformed Pediatric Metal Crown

Preformed metal pediatric crowns (PPCm) are currently considered the best method of restoring Primary molars affected by severe carious lesions compared to restorations made with various restorative materials (amalgams, composites, CVI-based materials). Due to their unsightly appearance, denounced by many parents, more aesthetic zirconia (PPCz) preformed pediatric crowns have been recently marketed. In the absence of an evaluation of the latter, this multi-center split-mouth two-year randomized clinical trial (RCT) proposes to to investigate the effectiveness of PPCz for the management of dental caries or structural anomalies. More specifically, the primary objective of this RCT is to assess in primary molars the success of PPCz in comparison with PPCm. The control treatment will be PPCm since this is the standard crown option. One hundred children and one aged at least 4 years must be recruited in ninedepartments of Pediatric Dentistry in the university hospitals of Bordeaux, Lille, Nancy, Nantes, Nice, Paris 1\&2, Strasbourg and Toulouse. They will be included if they have two similar primarymolars of the same arch (for example first right and left maxillary primary molars ) and equally affected, to be crowned. The two types of crowns to be used in the same child, PPCm(3M Espe) and PPCz(Ezpédo), will be affected by randomization using a computerized and centralized system: primary molars will first be allocated to PPCm and, one to two weeks later, the contralateral primary molar will be restored by PPCz. The children will be checked every 6 months for a period of 2 years after the placement of the two types of crowns . During these four control visits, primary and secondary outcomes will be assessed clinically and radiographically. The primary outcome is the success of the treatment defined by the absence of major failure. A composite measure of signs and symptoms leading to diagnosis of irreversible pulpitis or periradicular periodontitis will be used to define