Bulk-fill composites were developed with chemical structure intended to increase depth of cure and reduce polymerization contraction. Their translucency has also been examined in systematic research.
Clinical trials compared direct bulk-fill and incrementally placed restorations in permanent posterior teeth, including Class I and II restorations. This is the setting in which survival and failure rates were evaluated.
The usual comparison is conventional resin composite placed incrementally. Across nine randomised trials involving 632 restorations, failure rates did not differ significantly between the two approaches.
The single-layer technique can reduce operative steps and treatment time in direct posterior restoration. Evidence in the reviewed trials found this simplified approach without a detected loss of clinical quality.
Bulk-fill composites had survival and durability similar to conventional incrementally placed composite in posterior teeth across short- and longer-term follow-up. Marginal adaptation, discoloration and postoperative sensitivity were comparable in most studies.
