Shrinkage and polymerization stress of silorane- and dimer acid-based composites

Introduction . Recently, composites contaning monomers alternative to conventional dimetacrylates appeared on the market. According to the manufacturers, these new composites show lower volumetric shrinkage, which would lead to lower polymerization stress at the tooth/restoration interface.

Objectives . to evaluate the volumetric shrinkage and the polymerization stress (at two compliance levels) of composites with different organic matrix compositions.

Materials and methods . Nine commercial composites were tested. Seven were based on Bis-GMA (Durafill/Kulzer, Filtek Z250/3 M ESPE, Heliomolar/Ivoclar, Aelite LS/Bisco, Point 4/Kerr, Filtek Supreme/3 M ESPE, Extra Low Shrinkage/Saremco); one was silorane-based (Filtek LS/3 M ESPE); and one was based on a dimer acid dimetacrylate (N’Durance/Septodont). Volumetric shrinkage was measured using a mercury dilatometer ( n = 3). Polymerization stress was obtained by inserting composite between glass or PMMA rods ( = 5 mm, n = 5). Data were submitted to one-way ANOVA/Tukey test ( α = 0.05).

Results

Table. Means (SD) of polymerization stress (MPa) after five minutes for both substrates, and volumetric shrinkage (%) after 5 min. In the same column values with the same letter are not statistically different ( p > 0.05).
Composite Polymerization stress (MPa) Volumetric shrinkage (%)
Glass PMMA
ELS 2.6 (0.4) C 2.7 (0.3) c 2.20 (0.08) BC
Durafill 3.4 (0.3) C 2.6 (0.2) d 2.01 (0.03) D
Heliomolar 5.4 (0.5) B 2.8 (0.4) c 1.72 (0.03) E
Filtek Supreme 5.8 (0.6) B 4.2 (0.4) a 2.10 (0.03) CD
Aelite LS 6.2 (0.7) AB 3.4 (0.2) b 2.04 (0.13) CD
Filtek Z250 6.2 (0.8) AB 3.3 (0.2) bc 1.82 (0.07) E
N’Durance 6.7 (0.7) AB 3.9 (0.2) ab 2.29 (0.03) B
Point 4 4.3 (0.4) a 3.20 (0.02) A
Filtek LS 7.4 (0.9) A 4.3 (0.3) a 1.40 (0.02) F
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Nov 30, 2017 | Posted by in Dental Materials | Comments Off on Shrinkage and polymerization stress of silorane- and dimer acid-based composites
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