Pongprueksa P1, De Munck J2, Duca RC3, Poels K3, Covaci A4, Hoet P3, Godderis L3, Van Meerbeek B2, Van Landuyt KL5.
- 1KU Leuven BIOMAT, Department of Oral Health Sciences, KU Leuven (University of Leuven) & Dentistry, University Hospitals Leuven, Kapucijnenvoer 7, box 7001, 3000 Leuven, Belgium; Department of Operative Dentistry and Endodontics, Faculty of Dentistry, Mahidol University, No.6, Yothi road, Rajthawee, Bangkok 10400, Thailand.
- 2KU Leuven BIOMAT, Department of Oral Health Sciences, KU Leuven (University of Leuven) & Dentistry, University Hospitals Leuven, Kapucijnenvoer 7, box 7001, 3000 Leuven, Belgium.
- 3Centre for Environmental and Health, Department of Public Health and Primary Care, KU Leuven (University of Leuven), Kapucijnenvoer 35, 3000 Leuven, Belgium.
- 4Toxicological Center, University of Antwerp, Universiteitsplein 1, D.S.551, 2610 Wilrijk, Belgium.
- 5KU Leuven BIOMAT, Department of Oral Health Sciences, KU Leuven (University of Leuven) & Dentistry, University Hospitals Leuven, Kapucijnenvoer 7, box 7001, 3000 Leuven, Belgium. Electronic address: firstname.lastname@example.org.
The aim of this study was to determine the degree of conversion (DC) and the monomer release of three composite types when employed following a layer- and bulk-filling technique.
The release of monomers from a ‘conventional paste-like’ (Filtek Z250), a ‘conventional flowable’ (Filtek Supreme XTE Flowable) and a ‘bulk-fill’ flowable composite (Filtek Bulk Fill Flowable) from the same manufacturer (3M ESPE, Seefeld, Germany) was determined. Ten cylindrical specimens per composite were built, either in two 2-mm layers or in one 4-mm bulk. DC was measured at the specimen top and bottom surface using micro-Raman spectroscopy, after which the specimens were immersed in 2ml absolute ethanol for 24h at 37°C. This solution was refreshed weekly during six weeks and the concentration of BisGMA, BisEMA(6), BisPMA, UDMA, TEGDMA and BPA was determined by liquid chromatography/mass spectroscopy.
DC at the specimen top and bottom was similar except for the bulk-fill technique, which resulted in significantly lower DC at the specimen bottom. The release of BisGMA and TEGDMA was initially very high, but rapidly dropped in the second week. In contrast, the release of BisPMA and UDMA increased initially, but then declined towards the sixth week. BisEMA(6) release was relatively steady over time. All composites released small amounts of BPA. The total monomer release was significantly lower for the layer- than the bulk-filling technique.
The slightly reduced degree of conversion at 4-mm depth resulted in a higher monomer elution when the composite was applied following a bulk-fill application method.
Applying a flowable and a bulk-fill composite following a bulk-fill application method resulted in a significantly reduced degree of conversion at the bottom of polymerized composite specimens when compared to a layer-application method. This reduced polymerization degree was reflected in significantly increased monomer release.
Copyright © 2015 Elsevier Ltd. All rights reserved.
PMID: 26498727 [PubMed – in process] 1. J Dent. 2015 Dec;43(12):1448-55. doi: 10.1016/j.jdent.2015.10.013. Epub 2015 Oct 20.