The periodontium is the specialized tissues that both surround and support the teeth, maintaining them in the maxillary and mandibular bones. The word comes from the Greek terms περί peri-, meaning 'around' and -odont, meaning 'tooth'. Literally taken, it means that which is 'around the tooth'. Periodontics is the dental specialty that relates specifically to the care and maintenance of these tissues. It provides the support necessary to maintain teeth in function. It consists of four principal components, namely:The periodontium exists for the purpose of supporting teeth during their function and it depends on the stimulation it receives from the function for preservation of its structure. Therefore, a constant state of balance always exists between the periodontal structures and the external forces.