Osteoblasts, odontoblasts, cementoblasts and ameloblasts form calcified tissues. Following the initial deposition of hydroxyapatite, these extracellular matrix-producing cells make the calcified matrix more mature. Previous studies have provided a basis for the hypothesis that the cells express enzymes and remodel their specific extracellular matrix proteins to advance calcification during development of the tissue. This review summarizes our recent studies and relevant previous reports on expression of enzymes such as matrix metalloproteinases in development of bones and teeth as well as healing of bones. © 2012 Japanese Association for Oral Biology.