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Volume 6
Research & Reviews: Journal of Material Sciences
ISSN: 2321-6212
Ceramics 2018
May 14-15, 2018
May 14-15, 2018 | Rome, Italy
4
th
International Conference and Expo on
Ceramics and Composite Materials
Novel Ge- and Sn-based initiators for light induced radical polymerization of dental resins
B Gebhardt, U Fischer
and
N Moszner
Ivoclar Vivadent AG
P
olymerization of light-curing dental materials is initiated using camphorquinone (CQ) (λmax = 468 nm) with tertiary
arylamines (Norrish-II type) at wavelengths of 400-500 nm. Alternatively, acylphosphine oxides (APO; λmax = 385 nm)
and bisacylphosphine oxides (BAPO, λmax = 397 nm) are used to avoid discoloration by arylamines.The low solubility of BAPO
and limited VIS-absorption of APO limit their potential for many applications.[1, 2] The strong absorption and scattering of
wavelengths between 390-420 nm in methacrylate-based restorative materials limit the depth of photocure (DOC) achievable
in acceptable periods of time. To achieve the 4 mm DOC demanded from so-called „Bulk-Filling" restorative composites, the
bisacyl-germane based (BAGe) initiator Ivocerin® (λmax = 408 nm) was developed.[3, 4, 5] For further improvement of DOC,
bathochromically shifted Initiators are investigated. Novel Ge- and Sn-based initiators, such as tetraacyl-germane (TAGe) and
-stannane (TASn) initiators are herein discussed in comparison to Ivocerin®.[6, 7, 8] While λmax of TAGe and TASn show no
bathochromic shift relative to Ivocerin, the absorption at 440-480 nm overlaps significantly better with the emission spectrum
of dental light-curing unit (LCU). TAGe’s and TASn’s rapid photolysis results in complete and irreversible bleaching within
10 s irradiation using a LCU (390-510 nm). Dental composites comprising equimolar concentrations of initiators (0.2 wt.%
BAGe, 0.4 wt.% TAGe and TASn) were compared regarding DOC at different wavelengths (400-517 nm). Here, TASn gave
an increased DOC at higher wavelength in comparison to BAGe. The presented systems are highly interesting alternatives
to commercially available photo initiators. Their highly effective radical generation, excellent photobleaching, excitation at
biocompatible wavelengths and low toxicity of photolysis products offer great potential for a variety of different medical and
industrial applications.
Recent Publications:
1. Moszner N., Hirt T. (2012) New Polymer-Chemical Developments in Clinical Dental PolymerMaterials: Enamel-
Dentin Adhesives and Restorative Composites; Journal of Polymer Science, 50, 4369-4402.
2. Moszner N., Salz U. (2007) Recent Developments of New Components for Dental Adhesives and Composites,
Macromol. Mater. Eng.; 292, 245-271.
3. Moszner N., Zeuner F., Lamparth I., Fischer U. K. (2009) Benzoylgermanium Derivatives as novel visible-light
photoinitiators for dental composites; Macromol. Mater. Eng. 294 877-886
4. Moszner N., Fischer U. K., Salz U., Liska R., Burtscher P., Zeuner F., Ganster B., Gruber H. Polymerisierbare
Zusammensetzungen mit Acylgermaniumverbindungen als Initiatoren; US-Patent 7,605, (20.10.2009), EP-Patent
1,905,415 B1 (01.07.2009), Ivoclar Vivadent AG
5. Moszner N., Burtscher P., Vogel K., Todd J., Heintze S., Peschke A., (2013) Ivocerin – ein Meilenstein der Composite-
Technologie; Ivoclar Vivadent Report Nr.-19.
6. Moszner N., Fischer U. K, Lamparth I., Fässler P., Radebner J., Eibel A., Haas M., Gescheidt G., Stueger H. (2017)
Tetraacylgermanes as highly efficient photoinitiators for visible light cured dimethacrylate resins and dental
composites; J. Appl. Polym. Sci., 135, 46115
7. Moszner N., Lamparth I., Fischer U. K., Stüger H., Haas M., Gescheidt-Demner G. Acylgermanium-Photoinitiatoren
und Verfahren zu deren Herstellung; EP-Patent 3,150,641 A1 (05.04.2017), Ivoclar Vivadent AG
8. Moszner N., Fischer U. K., Burtscher P., Liska R., Knaack P., Mitterbauer M. Polymerizable compositions comprising
acyl tin photoinitiators; WO-Patent 2018/046438 A1 (15.03.2018), Ivoclar Vivadent AG
B Gebhardt et al., Res. Rev. J Mat. Sci. 2018, Volume 6
DOI: 10.4172/2321-6212-C1-015