Viscoelastic Properties of Contemporary Bulk-fill Restoratives: A Dynamic-mechanical Analysis

Abstract

This study investigated the viscoelastic properties of contemporary bulk-fill restoratives in distilled water and artificial saliva using dynamic mechanical analysis. The materials evaluated included a conventional composite (Filtek Z350), two bulk-fill composites (Filtek Bulk-fill and Tetric N Ceram), a bulk-fill giomer (Beautifil-Bulk Restorative), and two novel reinforced glass ionomer cements (Zirconomer [ZR] and Equia Forte [EQ]). The glass ionomer materials were also assessed with and without resin coating (Equia Forte Coat). Test specimens 12 × 2 × 2 mm of the various materials were fabricated using customized stainless-steel molds. After light polymerization/initial set, the specimens were removed from the molds, finished, measured, and conditioned in distilled water or artificial saliva at 37°C for seven days. The materials (n=10) were then subjected to dynamic mechanical testing in flexure mode at 37°C and a frequency of 0.1 to 10 Hz. Storage modulus, loss modulus, and loss tangent data were subjected to normality testing and statistical analysis using one-way analysis of variance/Dunnett's test and t-test at a significance level of p < 0.05. Mean storage modulus ranged from 3.16 ± 0.25 to 8.98 ± 0.44 GPa, while mean loss modulus ranged from 0.24 ± 0.03 to 0.65 ± 0.12 GPa for distilled water and artificial saliva. Values for loss tangent ranged from 45.7 ± 7.33 to 134.2 ± 12.36 (10). Significant differences in storage/loss modulus and loss tangent were observed between the various bulk-fill restoratives and two conditioning mediums. Storage modulus was significantly improved when EQ and ZR was not coated with resin.

Effect of Saliva Contamination on Microleakage of Open Sandwich Restorations

“…Moshaverinia et al reported that Equia-fil Forte is a powerful restorative material with a wide range of clinical applications in dental practice ( 38 ). In another study, it was reported that Equia Forte was significantly more rigid and less deformed than other materials under functional stress, thus supporting its indication for posterior restorations ( 39 ). This in vitro result was supported by a clinical follow up study of class II restorations performed by Gürgan et al ( 14 ) The development of such materials might be promising for the clinicians in terms of restorations extended margins to the root surface.…”

Evaluation of the bond strengths of restorative materials to primary tooth dentin treated with different pulpotomy techniques

“…In accordance with recent improvements in adhesive dentistry, the use of glass ionomers, and resin composites following pulpotomy has become highly popular (American Academy of Pediatric Dentistry, 2020; Atieh, 2008;Ong et al, 2018;Primosch, Ahmadi, Setzer, & Guelmann, 2005).…”

“…Moreover, these materials have smaller and more active silica particles and the flexural strength of these materials is improved by the use of acrylic acid molecules with higher molecular weights, thereby leading to increased matrix cross‐link density and an enhanced esthetic appearance (Schwendicke, Kniess, Paris, & Blunck, 2017). Limited studies reporting on the bonding success of glass hybrid materials to primary tooth dentin have indicated that these materials can be used as final restorative materials due to their properties abovementioned (Ong, Yap, Hong, Eweis, & Yahya, 2018; Sawalt, Paris, Blunck, & Schwendicke, 2017). In the light of all these data, the present study aimed to investigate the shear bonding strength of two restorative materials (glass hybrid vs. composite resin) to primary tooth dentin following the application of five different pulpotomy techniques (ferric sulfate, Biodentine ® , Nd:YAG laser, photobiomodulation, and APCP).…”

Clinical Performance of a Glass Hybrid Restorative in Extended Size Class 2 Preparations

“…tarafından, başka bir uzun süreli klinik çalışma rapor edilmiştir. 20 33 Amerikan Diş Hekimleri Birliği tarafından belirtildiği gibi, arka dişlerde kullanılması amaçlanan bir restoratif materyalin tam olarak kabul görebilmesi için 18 aylık klinik takipten sonra ağızda kalabilme oranının en az %90 olması gerekmektedir. 34 Bu çalışmada, 18 ay sonra EQUIA Forte 2. sınıf restorasyonlarının retansiyon oranının %93,7 olduğu görüldü.…”

“…Materyale farklı boyutlarda cam partiküllerin eklenmesinin ve yüzey örtücü uygulanmasının, bu materyalin fiziksel özelliklerinin yanı sıra estetik özellikleri iyileştirdiği işaret edilmektedir. 33,36 Bu çalışmada, renk uyumu CH restoratifin başlıca sorunu olarak görülmektedir. Başlangıçtan itibaren 6 restorasyonda, tüm değerlendirme zamanlarında renk uyumsuzluğu izlendi.…”