Comparison of wear resistance between highly filled flowable and conventional light curing composite in different pre-polymerization temperatures: a systematic literature review

Relevance of the problem: nowadays, popular method of restoring occlusal surfaces of posterior teeth is direct or semi- direct composite restorations. While restoring these surfaces, the wear resistance must be one of the main mechanical properties to pay attention to. In order to facilitate the use of resin composites, the production and development of flowable composites were started and the heating of conventional composites was introduced as one of the alternatives. However, the mechanical properties of flowable composites and the influence of higher pre-polymerization temperatures are still being questioned. Aim of the work: to co-ordinate scientific literature that investigates the wear resistance of resin composites by comparing highly-filled flowable and conventional light curing composites in different pre-polymerization temperatures. Materials and the methods: research was based on the PRISMA methodology and made using databases of PubMed, ScienceDirect and Taylor & Francis. During the research, special keywords were used. Articles published from January 1, 2010 to December 29, 2019 were searched and selected according to inclusion criteria. The quality of the studies was assessed using the Checklist for Reporting In Vitro Study tool. The data and results of the included publications were summarized and presented. Results: 8 publications were included. 4 of them investigate flowable composites, while the rest study the polymerization temperature of composite resins. Results of flowable composites wear resistance in the studies were better than those of conventional composites, also there were some similar ones. The surface microhardness of most investigated composites got higher as the temperature before polymerization was raised. Conclusions: Highly-filled flowable composites are more resistant to wear compared to conventional composites. Raising the pre-polymerization temperature helps to increase wear resistance of conventional composites