Healing of intrabony peri-implantitis defects following application of a nanocrystalline hydroxyapatite (Ostim™) or a bovine-derived xenograft (Bio-Oss™) in combination with a collagen membrane (Bio-Gide™). A case series. - Schwarz,F.; Bieling,K.; Latz,T. (J Clin Periodontol, 2006)