Silorane- and high filled-based"low-shrinkage" resin composites: shrinkage, flexural strength and modulus

Abstract

Silorane-and high filled-based "lowshrinkage" resin composites: shrinkage, flexural strength and modulus Abstract: This study compared the volumetric shrinkage (VS), flexural strength (FS) and flexural modulus (FM) properties of the low-shrinkage resin composite Aelite LS (Bisco) to those of Filtek LS (3M ESPE) and two regular dimethacrylate-based resin composites, the microfilled Heliomolar (Ivoclar Vivadent) and the microhybrid Aelite Universal (Bisco). The composites (n = 5) were placed on the Teflon pedestal of a videoimaging device, and VS was recorded every minute for 5 min after 40 s of light exposure. For the FS and FM tests, resin discs (0.6 mm in thickness and 6.0 mm in diameter) were obtained (n = 12) and submitted to a piston-ring biaxial test in a universal testing machine. VS, FS, and FM data were submitted to two-way repeated measures and one-way ANOVA, respectively, followed by Tukey's post-hoc test (α = 5%). Filtek LS showed lower VS than did Aelite LS, which in turn showed lower shrinkage than did the other composites. Aelite Universal and Filtek LS exhibited higher FS than did Heliomolar and Aelite LS, both of which exhibited the highest FM. No significant difference in FM was noted between Filtek LS and Aelite Universal, while Heliomolar exhibited the lowest values. Aelite LS was not as effective as Filtek LS regarding shrinkage, although both lowshrinkage composites showed lower VS than did the other composites. Only Filtek LS exhibited FS and FM comparable to those of the regular microhybrid dimethacrylate-based resin composite.

Microcomputed Tomography Evaluation of Volumetric Shrinkage of Bulk‐Fill Composites in Class II Cavities

“…Several studies have presented methods where the volumetric polymerization shrinkage is evaluated by testing the filling materials outside of the dental cavity . Microcomputed tomography (μCT) analysis has been recently used to evaluate polymerization shrinkage, allowing the study of 2D–3D images to qualitatively and quantitatively compare morphological changes on dental preparations .…”

In vitro evaluation of the shear bond strength between fiber posts and methacrylate or silorane based composite resins

“…The volumetric reduction that occurs because of cross bonding between the molecules in the CR organic matrix would be reduced in silorane-based CR due to the opening of a cationic ring previously to the formations of such chemical bonds, during the material polymerization [18,19,49,50]. It is known that silorane-based CR has significantly lower polymerization shrinkage, although showcasing similar mechanical properties to the methacrylate-based composites [51]. The volumetric decrease (shrinkage) of methacrylate-based composite materials could be responsible for the increase in the push-out bond strength of those materials to the FP through the tightening of the contact between post and CR.…”

Bulk Fill Composites: An Anatomic Sculpting Technique

“…The continuous search for a low shrinkage resin composite included new materials like ormocers and siloranes. Their resulting shrinkage stress and volume analysis showed promising results compared with regular methacrylate composites . However, the need for a specific adhesive system for this kind of material, as the limitation of repair with Bisphenol glycidyl metacrylate (BIS‐GMA) materials, has limited their widespread indication.…”

“…Most commonly used for improved esthetics in operative dentistry are ceramics of the particle‐filled glass family and composite resins. Although the latter represent a clinically validated class of material, several concerns remain regarding its polymerization shrinkage which has been an active research topic . It has been suggested that polymerization shrinkage may lead to contraction of the total composite volume, elicited by the cross‐linking of the monomeric chains, and eventually generate marginal leakage, post‐operative sensitivity, and dental cracks …”

“…Although the latter represent a clinically validated class of material, several concerns remain regarding its polymerization shrinkage which has been an active research topic. [1][2][3][4][5] It has been suggested that polymerization shrinkage may lead to contraction of the total composite volume, elicited by the cross-linking of the monomeric chains, and eventually generate marginal leakage, post-operative sensitivity, and dental cracks. 6,7 The dental industry is devoting efforts in innovation of composite resin-based materials due to a legal restrain treaty on mercury-based products recently announced by the United Nations Environment Programme of the Committee, which established a deadline, in 2020, to finish the commercialization of mercury-based products in 170 nations.…”