Effect of flowable composites on the clinical performance of non-carious cervical lesions: A systematic review and...

To answer the following PICO question (participant, intervention, comparator and outcome): Does flowable resin composite restorations compared with regular resin composites improve the marginal adaptation, marginal discoloration and retention rates of restorations placed in non-carious cervical lesions [NCCLs] of adults?, through a systematic review and meta-analysis.

MEDLINE, Scopus, Web of Science, LILACS, BBO, Cochrane Library and SIGLE were searched without restrictions, as well as the abstracts of the IADR, clinical trials registries, dissertations and theses in May 2016 (updated in April 2017).

We included randomized clinical trials (RCTs) that answered the PICO question. RCTs were excluded if cavities other than NCCLs were treated; indirect restorations; polyacid-based resins instead of composite resins were employed, restorations in primary teeth and restorations were placed in carious cervical lesions. The risk of bias tool of the Cochrane Collaboration was applied in the eligible studies and the GRADE tool was used to assess the quality of the evidence.

After duplicates removal, 5137 articles were identified. After abstract and title screening, 8 studies remained. Six were at "unclear" risk of bias. The study follow-ups ranged from 1 to 3 years. No significant difference was observed between groups for loss of retention and marginal discoloration in all follow-ups. Better marginal adaptation was observed for restorations performed with flowable composites. At 1-year (risk ratio=0.27 [0.10 to 0.70]) and 3-year (risk ratio=0.34 [0.17 to 0.71]) follow-ups, flowable composites showed a risk 73% and 66% lower than regular composites for lack of adaptation, respectively. The evidence was graded as moderate quality for loss or retention at 3 years due to risk of bias and low and very low for all other outcomes due to risk of bias, imprecision and inconsistency.

We have moderate confidence that the resin composite viscosity does not influence the retention rates at 3 years. Similar marginal discoloration and better marginal adaptation was observed for flowable composites but the quality of evidence is doubtful. (PROSPERO CRD42015019560).