Characterization of Methacrylate-Based Resins Containing Methacryl-Polyhedral Oligomeric Silsesquioxanes (MA-POSS-8).

Marietta Kreutz,Annette Wiegand,Marta Rizk,Bogna Stawarczyk,Nina Lümkemann

doi:10.3390/ma14071680

Marietta Kreutz, Annette Wiegand + Show 3 more

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https://doi.org/10.3390/ma14071680

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Abstract

The use of functionalized dental adhesives that might prevent degradation of the dentin hybrid layer has been proposed. The aim of the study was to characterize the physicochemical properties and the potential to induce mineral precipitation of methacrylate-based resins containing methacryl-functionalized polyhedral oligomeric silsesquioxane (MA-POSS-8). In total, six different compositions of resins based on bisphenol A glycerolate dimethacrylate (BisGMA, 40 to 60 wt.%), triethylene glycol dimethacrylate (TEGDMA, 5 to 35 wt.%) and 2-hydroxyethyl methacrylate (HEMA, 25 or 35 wt.%) were prepared and infiltrated with 5 wt.% MA-POSS-8. Unfilled resins served as control. Degree of conversion, viscosity, Martens hardness, indentation modulus, water sorption, and sol fraction were investigated. Polymerized specimens were examined by SEM/EDX for the presence of Ca/P precipitates after immersion in artificial saliva for 28 days at 37 °C. Statistical analysis was performed with two-way ANOVA and Tukey’s post-hoc test (p < 0.05). The degree of conversion ranged from 55.0 to 59.8% and was not affected by the addition of MA-POSS-8. Viscosity ranged from 60.0 to 422.3 mPa*s and was not affected by MA-POSS-8 except for one methacrylate-based resin with 60 wt.% BisGMA. Martens hardness and indentation modulus ranged from 161.3 to 138.1 N/mm2 and 4.2 to 3.9 kN/mm2 and were affected by MA-POSS-8 in only one resin (50 wt.% BisGMA, 25 wt.% TEGDMA, 25 wt.% HEMA). Water sorption was not affected by MA-POSS-8; sol fraction was below the detection limit. Formation of Ca/P precipitates was observed on all specimens of test and control groups. Material properties were not affected adversly by MA-POSS-8 except for slight differences in Martens Hardness, indentation modulus, viscosity, in some groups.

Highlights

Introduction published maps and institutional affilIn order to prevent the hybrid layer between a tooth and composite filling from its typical degradation, several attempts have been made to develop bioactive adhesives that would help to restore the hybrid layer during the degradation process [1,2]
ANOVA revealed no effect of the composition of experimental methacrylate-based resin (p < 0.101), but the presence of MA-POSS-8 significantly affected the results (p < 0.001)
MA-POSS-8 revealed no significant differences in the different groups (Table 3)

Summary

Introduction

Introduction published maps and institutional affilIn order to prevent the hybrid layer between a tooth and composite filling from its typical degradation, several attempts have been made to develop bioactive adhesives that would help to restore the hybrid layer during the degradation process [1,2]. Several bioactive particles were applied in dental resins or adhesives and studied for such applications, often for the costs of mechanical or other properties. Promising bioactive potential with consistent or improved mechanical properties of the resin could be shown with MA-POSS-8 nanoparticles (mean size 1 to 2 nm) as fillers [3,4,5,6]. MA-POSS-8 particles consist of an inorganic core from silicon and oxygen from which eight methacryl chains originate. The functionalization with the methacrylic chains facilitates further synthesis with the polymer matrix. The hybrid-like structure of the molecule allows a good distribution in organic substances and might improve the crosslinking density of the polymer [3,7]. Inducing mineral precipitation by MA-POSS-8 are assumed to base on a iations

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