Conclusions The present systematic review and meta- analysis indicate similar clinical performances of bulk-fill and conventional resin composites over a follow-up period of 12 to 72 months .
Clinical significance Based on the results of this study , the bulk-fill resin composites could be an alternative for direct restorations in posterior teeth .
Objectives The purpose of this systematic review was to compare the clinical performance of bulk-fill resin composites with conventional resin composites used for direct restorations of posterior teeth .
The research question was “ Do bulk-fill resin composites have a clinical performance comparable to conventional resin composites in posterior restorations ? ”
Design and Validity of Randomized Controlled Dental Restorative Trials
Background : The evidence stemming from trials on restorative material s is shaped not only by trial findings , but also trial design and validity . We aim ed to evaluate both aspects in r and omized controlled dental restorative trials published from 2005–2015 . Methods : Using systematic review methodology , we retrieved trials comparing  restorative or adhesive dental material s. Two authors independently assessed design , risk of bias , registration status , and findings of trials . Descriptive and regression analyses were performed . Results : 114 studies on 15,321 restorations placed mainly in permanent teeth of 5232 patients were included . Per trial , the median number of patients was 37 ( 25th/75th percentiles : 30/51 ) . Follow-up was 24 ( 20/48 ) months . Seventeen percent of trials reported on sample size calculations , 2 % had been registered . Most trials ( 90 % ) used US Public Health Service ( USPHS ) criteria , and had a high risk of bias . More recent trials were more likely to have been registered , to have reported on sample size calculations , to be of low risk of bias , and to use other than USPHS- criteria . Twenty-three percent of trials yielded significant differences between groups . The likelihood of such differences was significantly increased in older studies , studies with potential reporting bias , published in journals with high impact factor ( > 2 ) , longer follow-up periods , and not using USPHS- criteria . Conclusions : The majority of dental restorative trials published from 2005–2015 had limited validity . Risk of bias decreased in more recent trials . Future trials should aim for high validity , be registered , and use defined and appropriate sample sizes , follow-up periods , and outcome measures
Conclusions The present systematic review and meta- analysis indicate similar clinical performances of bulk-fill and conventional resin composites over a follow-up period of 12 to 72 months .
Clinical significance Based on the results of this study , the bulk-fill resin composites could be an alternative for direct restorations in posterior teeth .
Objectives The purpose of this systematic review was to compare the clinical performance of bulk-fill resin composites with conventional resin composites used for direct restorations of posterior teeth .
The research question was “ Do bulk-fill resin composites have a clinical performance comparable to conventional resin composites in posterior restorations ? ”