Degree of conversion and water sorption of self-adhesive and conventional flowable composites

Mohmad Amin Yektaei,Farhood Najafi,Mahdi Abbasi,Ladan Ranjbar Omrani,Fariba Motevasselian

doi:10.20396/bjos.v19i0.8658556

Abstract

Aim: Self-adhesive flowable composite resins have been recently introduced to the market. Degree of conversion (DC) and water sorption (WS) are two important parameters affecting the properties of restorative materials. This study aimed to assess the DC and WS of a self-adhesive flowable composite resin in comparison with two conventional flowable composite resins. Methods: Vertise Flow (VF) self-adhesive and Tetric-N Flow (TF) and Grandio Flow (GF) conventional flowable composites were evaluated in this in vitro, experimental study. The DC (n=3) was determined by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). The WS (n=7) was measured after 7 days of immersion in artificial saliva according to ISO 4049 specifications. Data were analyzed by one-way ANOVA and a post-hoc test (p<0.05). Results: VF showed the highest DC percentage (84.3%) followed by GF (72.79%) and TF (68.7%). The latter two had no significant difference (p=0.8). WS was the highest in VF (55.2 μg/mm3), and the two conventional flowable composites had a significant difference in WS (19.5 μg/mm3 in TF and 11 μg/mm3 in GF; p<0.001). Conclusions: Flowable composite resins had significant differences in DC and WS, and VF demonstrated the highest DC and WS.

Highlights

Composite resins are widely used due to the increased esthetic demands of patients and improvements in their mechanical properties
Composite resins can be classified into putty-like and flowable composite resins according to their consistency[1]
The monomers that are most widely used in commercially available composite resins include bisphenol-A glycidyl methacrylate (Bis-GMA) and urethane dimethacrylate (UDMA), which are high molecular weight monomers[1]

Summary

Introduction

Composite resins are widely used due to the increased esthetic demands of patients and improvements in their mechanical properties. Dental composites consist of two main components namely the organic matrix and the inorganic fillers. The monomers that are most widely used in commercially available composite resins include bisphenol-A glycidyl methacrylate (Bis-GMA) and urethane dimethacrylate (UDMA), which are high molecular weight monomers[1]. Low-viscosity monomers, such as triethylene glycol dimethacrylate (TEGDMA), are added as diluents to the highly viscous resin matrix in various concentrations to improve the degree of conversion (DC) and increase the filler content[1,2]. Flowable composites were designed for enhanced adaptation to the cavity walls and easy handling and application. They either have less filler loading or high proportion of diluent monomers added to viscous monomers[1,2]

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Conclusion