Periodontology

Periodontology or periodontics (from Ancient Greek περί, perí – 'around'; and ὀδούς, odoús – 'tooth', genitive ὀδόντος, odóntos) is the specialty of dentistry that studies supporting structures of teeth, as well as diseases and conditions that affect them. The supporting tissues are known as the periodontium, which includes the gingiva (gums), alveolar bone, cementum, and the periodontal ligament. A person who practices this specialty is known as a periodontist. Periodontology or periodontics (from Ancient Greek περί, perí – 'around'; and ὀδούς, odoús – 'tooth', genitive ὀδόντος, odóntos) is the specialty of dentistry that studies supporting structures of teeth, as well as diseases and conditions that affect them. The supporting tissues are known as the periodontium, which includes the gingiva (gums), alveolar bone, cementum, and the periodontal ligament. A person who practices this specialty is known as a periodontist. The term periodontium is used to describe the group of structures that directly surround, support and protect the teeth. The periodontium is composed largely of the gingivae, periodontal ligament, alveolar bone and cementum. The soft tissues and connective fibres that cover and protect the underlying cementum, periodontal ligament and alveolar bone are known as the gingivae. The gingivae are categorised into three anatomical groups; the free, attached and the interdental gingiva. Each of the gingival groups are considered biologically different, however, they are all specifically designed to help protect against mechanical and bacterial destruction. The tissues that sit above the alveolar bone crest are considered the free gingiva. In healthy periodontium, the gingival margin is the fibrous tissue that encompasses the cemento-enamel junction, a line around the circumference of the tooth where the enamel surface of the crown meets the outer cementum layer of the root. A natural space called the gingival sulcus lies apically to the gingival margin, between the tooth and the free gingiva. A non-diseased, healthy gingival sulcus is typically 0.5-3mm in depth, however, this measurement can increase in the presence of periodontal disease. The gingival sulcus is lined by a non-keratinised layer called the oral sulcular epithelium; it begins at the gingival margin and ends at the base of the sulcus where the junctional epithelium and attached gingiva begins. The junctional epithelium is a collar-like band that lies at the base of the gingival sulcus and surround the tooth; it demarcates the areas of separation between the free and attached gingiva. The junctional epithelium provides a specialised protective barrier to microorganisms residing around the gingival sulcus. Collagen fibres bind the attached gingiva tightly to the underlying periodontium including the cementum and alveolar bone and varies in length and width, depending on the location in the oral cavity and on the individual., The attached gingiva lies between the free gingival line or groove and the mucogingival junction. The attached gingiva dissipates functional and masticatory stresses placed on the gingival tissues during common activities such as mastication, tooth brushing and speaking. In health it is typically pale pink or coral pink in colour and may present with surface stippling or racial pigmentation. The interdental gingiva takes up the space beneath a tooth contact point, between two adjacent teeth. It is normally triangular or pyramidal in shape and is formed by two interdental papillae (lingual and facial).The middle or centre part of the interdental papilla is made up of attached gingiva, whereas the borders and tip are formed by the free gingiva. The central point between the interdental papillae is called the col. It is a valley-like or concave depression that lies directly beneath the contact point, between the facial and lingual papilla. However, the col may be absent if there is gingival recession or if the teeth are not contacting. The main purpose of the interdental gingiva is to prevent food impaction during routine mastication. The periodontal ligament is the connective tissue that joins the outer layer of the tooth root, being the cementum, to the surrounding alveolar bone. It is composed of several complex fibre groups that run in different directions and which insert into the cementum and bone via ‘Sharpey’s fibres’. The periodontal ligament is mostly comprised of collagen fibres, however it also houses blood vessels and nerves within loose connective tissue. Mechanical loads that are placed on the teeth during mastication and other external forces are absorbed by the periodontal ligament, which therefore protects the teeth within their sockets. In periodontal health, the alveolar bone surrounds the teeth and forms the bony socket that supports each tooth. The buccal and lingual plates and lining of the sockets are composed of thin, yet dense compact or cortical bone. Within the cortical plates and dental sockets lies cancellous bone, a spongy or trabecular type bone which is less dense than compact bone.