Histologic section of collagen membrane groups at 4 (a, c) and 8 (b, d) weeks after implantation: (a) Membrane was collapsed and absorbed at 4 weeks. (c, d) Abundant infiltration of ST between the NB was observed, and discrete NB was formed. (Magnifications were ×12.5 in Division of Integrative Biosciences and Biotechnology, and ×40 in others.) ST, soft tissue; NB, new bone. Color images available online at www.liebertpub.com/tea