Structures Around Tooth
There are some structures around the tooth. Periodontal ligament is the supporting structure of a tooth. It is made up of thousands of fibres which help to attach the tooth to surrounding tissues and to allow sensations of touch and pressure. Oral Mucosa is the moist tissue that lines the mouth. Gingivae is the soft tissue that immediately surrounds the teeth and bone, which protects the bone and the roots of the teeth and provides an easily lubricated surface. Alveolar bone is the bone of the jaw which provides a socket to surround and supports the roots of the teeth. In orthodontics, a tooth can be moved through the alveolar bone when an appropriate orthodontic force is applied. The cellular responses in the area of bone under compressive force will result in bone resorption, whereas the cellular responses in the
Fig. 6.4 Potential approaches for tooth regeneration. (a) Scaffold based approach. (b) Cell aggregation based approach. (c) Stem cell homing based approach  (Copyright permission from Elsevier Science Ltd)
area of bone receiving tension from periodontal ligaments will result in bone deposition . Orthodontic tooth movement generates a change of the local vascularization and a biochemical adaptive response which leads to the release of arachidonic acid, growth factors, metabolites, cytokines, and various enzymes .