Evaluation of anionic collagen membranes in the treatment of class II furcation lesions: an histometric analysis in dogs - Cirelli, Joni Augusto; Marcantonio Júnior, Elcio; Marcantonio, Rosemary Adriana Chiérici; Lia, Rafael Carlos Comeli; Goissis, Gilberto; Rossa Júnior, Carlos (Biomaterials, 1997)