Effect of pre-heating on the mechanical properties of silorane-based and methacrylate-based composites

Abstract

BackgroundThe use of composites in dental restoration has been commonly criticized, due to their underwhelming mechanical properties. This problem may be solved partially by preheating. The present research aims to determine the effect of preheating on the mechanical properties of two different classes of composites. Material and Methods A Silorane-based (Silorane) and a Methacrylate-based (Z250) composite were preheated to different temperatures (25, 37, and 68 °C) and afterwards were tested with the appropriate devices for each testing protocol. The material’s flexural strength, elastic modulus, and Vickers microhardness were evaluated. Two-way ANOVA, and Tukey’s post hoc were used to analyze the data. Results Microhardness and elastic modulus increased with preheating, while flexural strength values did not increase significantly with preheating. Furthermore the methacrylate-based composite (Z250) showed higher values compared to the Silorane-based composite (Silorane) in all the tested properties. Conclusions Preheating Silorane enhances the composite’s microhardness and elastic modulus but does not affect its flexural strength. On the other hand, preheating Z250 increases its microhardness but does not change its flexural strength or elastic modulus. In addition, the Z250 composite shows higher microhardness and flexural strength than Silorane, but the elastic modulus values with preheating are similar. Therefore Z250 seems to have better mechanical properties making it the better choice in a clinical situation. Key words:Composite, elastic modulus, flexural strength, microhardness, preheating.

The effect of preheating resin composites on surface hardness: a systematic review and meta-analysis

“…This systematic review evaluated 13 studies that were conducted to evaluate the microhardness of 16 different brands of resin composites. Six of the studies (46%) evaluated the microhardness of the Z250 microhybrid resin composite [192627282930]. Two studies (15%) evaluated the microhardness of the Filtek Silorane resin composite (3M ESPE) [2729], and 2 other studies (15%) evaluated the microhardness of the TPH Spectra microhybrid resin composite (Dentsply Caulk, Milford, DE, USA) [816].…”

“…Six of the studies (46%) evaluated the microhardness of the Z250 microhybrid resin composite [192627282930]. Two studies (15%) evaluated the microhardness of the Filtek Silorane resin composite (3M ESPE) [2729], and 2 other studies (15%) evaluated the microhardness of the TPH Spectra microhybrid resin composite (Dentsply Caulk, Milford, DE, USA) [816]. The remaining studies evaluated other resin composites: Charisma (Heraeus-Kulzer, Hanau, Germany) [21], Enamel Plus HFO (Micerium SpA, Avegno, Italy), Opallis (FGM Produtos Odontologicos, Joinville, Brazil), Ceram X Duo (Dentsply DeTrey GmbH, Konstanz, Germany) [22], Grandio (Voco, Cuxhaven, Germany), Simile (Jeneric Pentron, Wallingford, CT, USA), Tetric N-Ceram (Ivoclar Vivadent, Schaan, Liechtenstein) [23], Microhybrid Esthet-X (Dentsply Caulk) [16], light-cured low-stress posterior bulk fill flowable base composites, Surefil SDR (Dentsply Caulk) [24], Vit-l-escence (microhybrid, Ultradent, Salt Lake City, UT, USA), Tetric Ceram HB (Ivoclar Vivadent), Filtek Supreme Ultra (3M ESPE), Filtek LS Low Shrink Posterior Restorative System (3M ESPE) [25], and a nanofilled composite (Filtek Supreme Plus, 3M ESPE) [19].…”

“…Moreover, most of the reviewed articles were recently published. Two studies were published in 2017 [1924], 1 was published in 2016 [27], 3 were published in 2015 [222330], 1 was published in 2014 [25], and 1 was published in 2013 [21]. The rest of the studies were published between 2007 and 2011 [8161928].…”

“…The rest of the studies were published between 2007 and 2011 [8161928]. All the reviewed studies (100%) used either the Vickers or Knoop hardness tests as the primary testing method to determine microhardness [8161921222324252627282930]. However, the studies showed considerable variation in the secondary testing methods: shrinkage gap formation [21], the 3-point bending test [22], depth of cure [1624], viscosity [825], degree of conversion, plasticization [24], flexural strength, and the elastic modulus [27].…”

“…Of the remaining 112 manuscripts, 1 clinical trial and 1 review article were excluded, and 97 other studies were excluded because they evaluated the effect of preheating a composite on microleakage and other viscoelastic and mechanical properties of composites than microhardness. Finally, 13 studies were selected [8161921222324252627282930]. The detailed study selection procedures are illustrated in a flowchart (Figure 1).…”