Indentation hardness

Polymerization

Irradiance

Curing (chemistry)

Materials science

Photopolymer

Polymer

Physics

Optics

Microstructure

Composite material

Photoinitiator

Medicine

Monomer

Journal of Esthetic and Restorative Dentistry

ABSTRACT Objective To evaluate scientific evidence regarding depth of cure of bulk‐fill resin composites (BFRCs) and related factors. Material and Methods PubMed/Medline, Embase, Scopus, and ISI Web of Science databases were accessed from October 2016 to May 2017. Investigations published in English language, assessing depth of cure of BFRCs by microhardness test and/or degree of conversion (DC) were included. Studies using exclusively ISO 4049, employing specimens deepness less than 4 mm, as well as those not reporting exposure time and/or irradiance from light curing units (LCUs) were excluded. Results In total, 742 studies were found from which 33 were included. From 21 studies evaluating BFRCs microhardness, 10 showed acceptable bottom/top ratios (≥0.8) for all tested materials. However, material‐dependent results and non‐satisfactory bottom/top microhardness ratios (&lt;0.8) were reported in 9 and 2 investigations, respectively. From 19 studies that assessed DC, 11 showed acceptable results (≥50%) for all tested BFRCs, while 8 studies reported material‐dependent outcomes. Overall, irradiance from LCUs ranged from 650 to 1330 mW/cm 2 and exposure time from 5 to 60 seconds. Favorable depth of cure results were observed with the use of LCUs emitting irradiance ≥1000 mW/cm 2 and exposure times ≥20 seconds. Conclusions High depth of cure rates by BFRCs, depends on some factors as material, irradiance and exposure time. Polywave LCUs were useful but not essential on polymerizing alternative photoinitiator‐containing BFRC. Clinical Significance LED curing devices (polywave or monowave) displaying an irradiance ≥1000 mW/cm 2 and 20 seconds of exposure time are imperative to accomplish successful polymerization of most BFRCs.

Depth of cure of bulk fill resin composites: A systematic review