Use of flowable resin composite as an intermediate layer in class II restorations: a systematic review and...

To investigate the influence of an intermediate layer of a flowable resin composite in class II resin composite restorations.

The authors searched MEDLINE via PubMed, Scopus, LILACS, Embase, and Web of Science electronic databases, and the ClinicalTrials.gov website to identify laboratory and clinical studies that evaluated class II cavities with resin composite restorations with or without an intermediate layer of flowable resin composite. Two authors independently selected the studies, extracted the data, and assessed the risk of bias and the quality of the evidence. Meta-analyses were performed using RevMan5.3 with fixed-effects model comparing bond strength (MPa), fracture strength (Newton), and clinical (number of failures) outcomes between restorative techniques (with or without flowable resin composite as an intermediate layer).

From 1707 potentially eligible studies, 140 in vitro studies and 14 clinical studies were selected for full-text analysis, and 11 were included in the systematic review, being 7 in vitro and 4 clinical studies. There was no statistically significant difference between the restorative techniques considering the outcomes evaluated. The heterogeneity found was null. The risk of bias was classified as medium for in vitro studies and unclear in most clinical studies. The quality of the evidence of the clinical studies was low.

The use of flowable resin composite as an intermediate layer does not improve the effectiveness of the class II restorations based on laboratory and clinical outcomes.

Flowable resin composite as an intermediate layer may be used for class II restorations; however, this technique does not improve the effectiveness of the class II restorations.