The aim of this study was to demonstrate hydrogen donating capability of poly(ethylene oxide) (PEO) in type II photoinitiated free radical polymerization for dental applications. Photopolymerization kinetics of the dental resin mixtures were monitored by Photo-DSC. H-NMR spectroscopic and GPC studies were also performed in order to gain insight to the hydrogen abstraction mechanism. The effect of molecular weight of PEO on the photoinitiation efficiency was investigated. Photolysis of solutions containing benzophenone and PEO in the presence of a radical scavenger namely, 2,2,6,6-tetramethylpiperidine-N-oxyl free radical (TEMPO) revealed that photoexcited benzophenone readily abstracts hydrogen from methylene groups present in PEO backbone. It was demonstrated that such photoinitiating system can be converted to a versatile grafting process. PEO possessing photochemically attached TEMPO units initiates the nitroxide mediated radical polymerization of styrene upon heating at 110 A degrees C leading to the formation of poly(ethylene oxide-g-styrene) graft copolymer. Potential use of the photoinitiating system in dental formulations was also demonstrated. The polymeric nature, water solubility and nontoxicity make PEO a promising candidate as hydrogen donor in dental formulations.