Clinical Behavior of Modified-monomer-resin Restorations and Methacrylate-resin Restorations: a Meta-analysis

Objectives: To conduct a meta-analysis to assess the clinical behavior of restaurations performed with composite-resins containing new and modified monomers in comparison with traditional methacrylate-based composite-resins.
Methods: This systematic review was registered at Prospero data system (CRD42015023940). Studies were searched in the electronic databases PubMed, Web of Science, Scopus, Lilacs and EMBASE according to a predefined search strategy. The inclusion criteria were as follow: (1)randomized controlled clinical trials with at least six months of follow-up; (2)studies investigating composites with new and modified monomers designed to reduce polymerization shrinkage; (3)studies conducted with class I or II restorations in the permanent dentition; and (4)studies that assessed at least one of the following criteria: marginal integrity/adaptation, marginal discoloration, secondary caries, retention of composite restorations, and postoperative sensitivity. Two independent reviewers analyzed the articles to determine inclusion and risk of bias.
Results: From 19 included articles, 3 compared ormocer, 13 silorane and 3 bulk-fill composite-resins to methacrylates-based resins. The longest clinical follow-up time was 60 months. The meta-analysis of the data in the included studies demonstrated that only one variable (marginal adaptation after 12 months) showed statistically significant outcomes, in which methacrylates-based composites presented significantly better results than composite-resins containing modified monomers.
Conclusions: The good level of the scientific evidence as well as the overall low risk of bias of the included studies indicate that composites with silorane, ormocer or bulk-fill type modified-monomers have a clinical performance similar to conventional composite-resins.