Pre-Heating Effect on Monomer Elution and Degree of Conversion of Contemporary and Thermoviscous Bulk-Fill Resin-Based Dental Composites

Edina Lempel,Sára Jeges,Katalin Böddi,József Szalma,Dóra Kincses,Zsuzsanna Őri,Bálint Viktor Lovász,Sándor Kunsági-Máté

doi:10.3390/polym13203599

Edina Lempel, Sára Jeges + Show 6 more

Open Access

https://doi.org/10.3390/polym13203599

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Journal: Polymers	Publication Date: Oct 19, 2021
Citations: 14	License type: CC BY 4.0

Affiliation: University of Pecs, Szent János Kórház

Abstract

Detection of unreacted monomers from pre-heated resin-based dental composites (RBC) is not a well-investigated topic so far. The objectives were to determine the temperature changes during the application and polymerization, the degree of conversion (DC) and unreacted monomer elution of room temperature (RT), and pre-heated thermoviscous [VisCalor Bulk(VCB)] and high-viscosity full-body contemporary [Filtek One Bulk(FOB)] bulk-fill RBCs. The RBCs’ temperatures during the sample preparation were recorded with a K-type thermocouple. The DC at the top and bottom was measured with micro-Raman spectroscopy and the amounts of eluted BisGMA, UDMA, DDMA, and TEGDMA were assessed with High-Performance Liquid Chromatography. The temperatures of the pre-heated RBCs decreased rapidly during the manipulation phase. The temperature rise during photopolymerization reflects the bottom DCs. The differences in DC% between the top and the bottom were significant. RT VCB had a lower DC% compared to FOB. Pre-heating did not influence the DC, except on the bottom surface of FOB where a significant decrease was measured. Pre-heating significantly decreased the elution of BisGMA, UDMA, DDMA in the case of FOB, meanwhile, it had no effect on monomer release from VCB, except TEGDMA, which elution was decreased. In comparison, RBC composition had a stronger influence on DC and monomer elution, than pre-cure temperature.

Highlights

IntroductionIn the case of resin-based composite (RBC) restorations, expediting polymerization, increasing of maximum layer thickness, and the degree of monomer conversion can be considered as the main objectives [1]
The temperature of the 46 ◦ C pre-heated Filtek One Bulk (FOB) decreased to 33.4 ◦ C as it was removed from the warming device and started to be applied into the mold and showed further temperature drop of −1 ◦ C during the condensation
Higher degree of conversion (DC) values were achieved on the top of the room temperature and pre-heated investigated bulk-fill resin-based composite (RBC) than on the bottom

Summary

Introduction

In the case of resin-based composite (RBC) restorations, expediting polymerization, increasing of maximum layer thickness, and the degree of monomer conversion can be considered as the main objectives [1]. Successful composite restoration, the most important factors, among others, are mechanical properties, handling characteristics, polymerization stress, marginal adaptation, and degree of polymerization [2]. DC is influenced by several factors, such as light exposure conditions, composition, shade, opacity, and thickness of the RBC, pre-cure temperature plays an important role in the polymerization process [5,6]. As the success of RBC restorations depends on their polymerization and DC, the influence of temperature has become one of the central issues of several studies [7,8]

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