Extracellular matrix expression and periodontal wound-healing dynamics following guided tissue regeneration therapy in canine furcation defects

Aim: Temporal and spatial expression pattern of extracellular matrix (ECM) components in furcation defects following guided tissue regeneration (GTR) compared with open-flap debridement (OFD). Material and Methods: In 21 dogs, mandibular second and fourth pre-molars were treated with one non-resorbable and three different resorbable membranes. Third pre-molars were treated by OFD. After 2, 4, 8 weeks and 3, 6, and 12 months, tissues were analysed by immunohistochemistry for collagen I (Col-I) and III (Col-III), fibronectin (FN), bone sialoprotein (BSP), and osteopontin (OPN). Results: At 2 weeks, the defect was mainly occupied by FN+ granulation tissue (GT), which was sequentially replaced by new connective tissue expressing FN, Col-I, and increasingly Col-III. Following superficial resorptions by OPN+ osteoclasts and odontoclasts, cementum and bone formation ensued with strong expression of BSP and OPN along bone and tooth surfaces. Deposition of Col-I, FN, BSP and OPN+ cementoid and osteoid became evident after 4 weeks. Extrinsic fibres of cementum and bone stained intensely for Col-Ill. The newly formed periodontal ligament expressed FN, Col-I and Col-III, but no BSP or OPN. Conclusions: The spatial ECM expression was similar for OFD and the different GTR methods, although the timing and quantity of ECM expression were influenced by wound stabilization and inflammatory reactions.