Harald Heymann, and in 1997 co-authored the first article on extended treatment (six-months) of tetracycline-stained teeth using this technique. He has completed further research and over 70 publications on the NGVB technique and the topic of bleaching and esthetics, including the first papers on treating bleaching sensitivity with potassium nitrate, direct thermoplastic tray fabrication, and bleaching primary teeth.