1,3-Diethyl-2-thiobarbituric acid as an alternative coinitiator for acidic photopolymerizable dental materials

Abstract

The ethyl-4-dimethylaminobenzoate (EDAB) is widely used as a coinitiator of the camphorquinone (CQ), but in acidic circumstances it might present some instability, reducing the polymerization efficiency of the material. Considering this, new coinitiators are being evaluated. Hence, this study evaluated the kinetic of polymerization (KP), the degree of conversion (DC), and the rate of polymerization (RP ) of experimental resin adhesives containing 1,3-diethyl-2-thiobarbituric acid (TBA) as a coinitiator of the CQ. The experimental monomeric blend was prepared with bisphenol A glycidyl dimethacrylate, 2-hydroxyethyl methacrylate, and acidic monomers. CQ was added at 1 mol % as photoinitiator. Six groups were formulated: four containing concentrations of 0.1, 0.5, 1, and 2 mol % of TBA, one without coinitiator, and the last one containing 1 mol % of EDAB (control group). The KP and the RP were performed using real-time Fourier Transform infrared spectroscopy. The group without coinitiator has not formed a polymer, whereas the addition of TBA resulted in the conversion of monomers in polymer. The DC of the adhesives was as higher as the increase in the TBA content. The group with 2 mol % of TBA presented improved DC and reactivity (RP ) than the other groups and the control one. Hence, the TBA has performed as a coinitiator of the CQ for the radical polymerization of methacrylate resin adhesives and it has improved the DC and the reactivity of the materials. Thus, it is a potential coinitiator for the photopolymerization of dental materials.

Moving Towards a Finer Way of Light-Cured Resin-Based Restorative Dental Materials: Recent Advances in Photoinitiating Systems Based on Iodonium Salts

“…That, in turn, can contribute to amine consumption and decrease the efficiency of the initiating system. The limitations of amines, especially EDAB, include not only unstable in acidic conditions [132], unstable in acidic dental resin formulations [133,134], but also sensitivity to oxygen inhibition [135]. In addition, amines are a cytotoxic and genotoxic factor [101].…”

Novel 1,3-diethyl-2-thiobarbiturates of 2,2′-bipyridine and 1,10-phenanthroline: Synthesis, crystal structure and thermal stability

“…1), although it and its compounds can find practical application. For example, HDetba is proposed as an alternative to acidic photopolymerizable dental materials [10] and for determining nicotine and twelve metabolites in human urine and animals using high-performance liquid chromatography [11]. Its compounds can be used as NLO materials [12] and for the manufacture of field-effect transistors [13].…”

A low migration phosphine to overcome the oxygen inhibition in new high performance photoinitiating systems for photocurable dental type resins

“…The restoration of teeth commonly involves a methacrylate based dental composition that is polymerized in air in the presence of suitable photoinitiating systems (PISs) . The most commonly used PISs are based on a photoinitiator (camphorquinone, CQ) and a co‐initiator (such as ethyldimethylaminobenzoate, EDB) . Other usable compounds include, for example, hydrogen, electron/proton or electron donors, β‐allyl sulfones, cleavable ketones (e.g.…”