Project title: Synthesis and testing of application properties of new high-performance photoinitiating systems dedicated to new generation dental photocuring composites

Principal investigator: MSc. Eng. Monika Topa-Skwarczyńska

Obtained funds: 220 000 PLN

Project duration: Start day: 2018-09-19 – End day: 2022-09-18

Short description of the project:

The main goal of this project is the synthesis of high-performance photoinitiating systems dedicated to photo-curable polymer dental composites for dental fillings. Due to the long search for very effective photoinitiating systems for a new generation of dental composite materials based on epoxy resins, oxiranes, oxetanes and siloranes, the project proposed a research plan regarding application issues for this type of materials. In addition, the scope of research work has been extended to include cognitive aspects related to the development of completely new initiating systems (single-component or multi-component) showing the versatility of action through the possibility of photochemical initiation:

• cationic photopolymerization with ring opening for new generation dental materials, e.g. Filtek^TM Siloran  by 3M; 
• free-radical photopolymerization as standard used in photocurable dental materials;
• hybrid photopolymerization involving cationic ring-opening photopolymerization and radical chain photopolymerization.

For this purpose, first, the synthesis of completely new systems was planned for the role of initiating systems based on onium salt systems, including iodonium and sulfonium salts with a co-initiator or photosensitizer in the form of chromophores with absorption characteristics adapted to the currently used Vis-LED dental light sources (from 400 nm to 550 nm). The photoinitiators obtained in this way with appropriate absorption characteristics are also tested in terms of their effectiveness and initiation efficiency of cationic and radical photopolymerization of monomers used as a matrix in dental composites.

Project effects:

As part of the project, new initiation systems dedicated to the preparation of next-generation dental composites have already been developed, which have a number of significant advantages compared to the standard camphorquinone / aromatic amine initiator system.