Benzoylgermanium Derivatives as Novel Visible‐Light Photoinitiators for Dental Composites

Abstract

New dibenzoylgermanium derivatives are synthesized starting from various dithioacetal protected benzaldehydes by a coupling reaction with different dialkyldichlorogermanes and subsequent oxidative cleavage of the protecting group. The synthesized germanium compounds show a significantly stronger blue light absorption than camphorquinone. During irradiation, the dibenzoylgermanium derivatives undergo photodecomposition under formation of radicals. Therefore, the different dibenzoylgermanium derivatives are used as amine‐free visible‐light photoinitiators for dental cements and composites. Composites based on the different dibenzoylgermanes are storage‐stable and show a significantly improved bleaching behavior over composites with CQ/amine photoinitiators.magnified image

Polymer-Based Direct Filling Materials

“…Another example of modification of the initiator technology is Tetric EvoCeram Bulk Fill (Ivoclar-Vivadent). This material utilizes a germanium-based photoinitiator, with maximum wavelength of absorption at 420 nm [89]. This molecule presents a much higher quantum yield than the camphorquinone/amine system, and also results in the formation of two active radicals, which may facilitate propagation of reactive species even at depths where the light intensity is significantly diminished [89].…”

“…This material utilizes a germanium-based photoinitiator, with maximum wavelength of absorption at 420 nm [89]. This molecule presents a much higher quantum yield than the camphorquinone/amine system, and also results in the formation of two active radicals, which may facilitate propagation of reactive species even at depths where the light intensity is significantly diminished [89]. In vitro investigations have demonstrated that these materials may require at least 20 s of photoactivation to achieve levels of conversion comparable to incrementally placed conventional composites [90].…”

Visible Light Curable Restorative Composites for Dental Applications Based on Epoxy Monomer

“…The glass fillers were silanized analogous to the method already reported in literature [18]. Typically, the glass fillers were silanized by mixing them with 1 wt% of water and 5 wt% of 3-glycidyloxypropyltrimethoxysilane at room temperature over a period of 2 h, and drying the modified fillers at 50 °C for 4 days.…”

Monomers for adhesive polymers, 17.aSynthesis, photopolymerization and adhesive properties of polymerizable phosphonic acids bearing urea groups

“…Ivocerin® (0.2 mol%) was added as photoinitiator. [32] Homopolymerization of phosphonates 3a, 3b, 8a, Scheme 2. synthesis of monomers 9a and 9b. Scheme 3. synthesis of monomer 10.…”