The periodontium the word comes from Greek terms peri- meaning “around” and –odont meaning “tooth”. The periodontium is a connective tissue organ covered by an epithelium that the teeth to the bones of the jaws its surrounds and supports the teeth maintaining them in the maxillary and mandibular bone. It comprises of cementum, periodontal ligament, bone lining the tooth socket (alveolar bone) and that part of the gingiva facing the tooth (dentogingival junction).

The periodontium exist 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 exist between the periodontal structures and the external forces.

From a biological prospective the periodontal profession focusses on one of the most unusual tissues in the human body that is the three layered periodontal attachment apparatus consisting of a soft periodontal ligament sandwiched between two mineralized tissues, root cementum and the bone of the alveolar socket. In the healthy teeth this periodontal complex is effectively protected from oral pathogens by the oral mucosa and the junctional epithelium.

If we look at the majority of the vertebrates the tooth is attached to the tooth bearing elements through the ankylosis including all amphibians most species of teleost fish and most reptiles with the exception of crocodiles. Ligamentous tooth attachment only occurs in a small number of fish species such as sea bream, sawfish, pike, hake and angler fish. It is found that birds and turtles do not have true teeth are replaced by an intermediate form of tooth attachment, a mineralized periodontal ligament. It is found that gomophosis in mammals the alveolar socket remains attached to the jaw during tooth replacement as compared to crocodile form of tooth attachment. It is found that the caiman periodontium contains traces of mineralization in between sharpeys fibers. Of all the creations the mammals feature and integral complex periodontium in which both the fibrous non mineralized periodontal ligament and the surrounding bony socket are proprietary to each individual teeth.

Being aware of the evolution of the periodontal ligament and the thorough understanding of the property will allow the clinicians to modify their clinical procedures.