1Periodontium comprises of 4 structures, two soft tissues and two hard tissues which support and helps in functioning of the teeth. The two soft tissues are 1) Gingiva and periodontal ligament and the two soft tissues are 1) Cementum and alveolar bone.
2Gingiva is a vascular tissue that surrounds the teeth and covers the alveolar bone. Near the teeth it forms a V- shaped sulcus called gingival sulcus. It forms interdental papilla, marginal gingiva and attached gingiva which plays a very important role in mastication, aesthetics and tissue maintenance. It comprises of epithelium, connective tissue rich in fibroblasts, collagen fibres and immune cells. It rarely undergoes fibrosis because of the rich vascularity.
3The gingival sulcus is an important tooth soft tissue junction where the host interacts with various bacteria present in the plaque. The depth of the gingival sulcus in health is 2-3mm. when the sulcus depth deepens it results in the formation of pocket, two types namely gingival and periodontal.
4The gingival sulcus is continuously flushed by the gingival crevicular fluid (GCF). It is transudate in health and exudate in disease. The gingival fluid is composed of various organic and inorganic molecules. It has been used in research as a potential fluid for several biomarkers.
5Cementum is an avascular mineralized connective tissue that surrounds the root. It forms the cemento-enamel junction when it meets the enamel. CEJ is an important landmark. Acellular cementum is important in tissue regeneration while cellular cementum helps in tissue repair. It provides attachment to the sharpey’s fibers.
6Periodontal ligament is a hour-glass shaped, slender, highly vascular connective tissue that surrounds the root of the teeth. It provides collagen fibre bundles which help in attachment of the tooth to the cementum and alveolar bone. It is rich in vascular supply and provides nutrition to the surrounding tissues including avascular cementum.
7The periodontal ligament is made of host of cells including fibroblasts, Pluripotent stems cells, osteoblasts, cemento blasts and cell rests of Malassez. All these cells including ectomesenchymal cells play an important role in the regeneration of tissues.
8The principle fibre bundles seen in periodontal ligaments v.i.z crestal, horizontal oblique, apical, intterradicular and trans septal fibres play an important role in occlusal force transfer, proprioception and resistance to various forces acting on the teeth. Absence of periodontal ligament fibres leads to ankyloses of the teeth.
9The alveolar bone is a mineralized, dynamic connective tissue that forms the socket and provides the attachment to the teeth. It is highly vascular and contains outer and inner cortical plates with trabecular bone in between. The bundle bone or cribriform plate provides attachment to the sharpey’s fibres is perforated and highly vascular
10The bilayered periosteum is the outer most covering of the bone and plays an important role in providing nutrition and vascular supply of the bone. The periosteum is unique and has very important role in surgical procedures and regeneration of bone.
Dr. Rajesh Hosadurga,
Professor, Manipal University College,