Periodontology د. باسم الاعسم

The gingiva

The gingiva is the tissue that cover the cervical portion of the teeth and the alveolar processes of the jaws. The function of gingiva is to provide a tissue seal around the cervical portions of the teeth and cover the alveolar processes of the jaws.

Boundaries of the gingiva are: The coronal boundary, or upper edge, gingival margin, at the cervix of each tooth, surrounds it, and forms there the epithelial attachment by means of a ring of specialized tissue. The apical boundary, or lower edge, the alveolar mucosa at the mucogingival line and cover the coronal aspect of the alveolar process. On the palatal aspect, the mucogingival line is absent; here, the gingiva is a part of the keratinized, non-mobile palatal mucosa

Free gingiva Gingival sulcus Interdental gingiva Attached gingiva

The free gingival groove is a shallow linear depression that separates the free and attached gingiva. The mucogingival junction is the clinically visible boundary where the pink attached gingiva meets the red, shiny alveolar mucosa.

The free gingiva (marginal gingiva). The free gingiva is located coronal or above the CEJ, surrounding the tooth in a turtleneck or cuff like manner.

The healthy free gingiva is coral (salmon) pink in color, knife edge in contour about 1.5 mm width, firm in consistency and smooth in texture. The tissue of the free gingiva fits closely around the tooth but is not directly attached to it. This tissue, because it is unattached, may be gently stretched away from the tooth surface with a periodontal probe. The free gingiva also form the soft tissue of the small invagination or sulcus which is called the gingival sulcus. The gingival margin follows the contours of the teeth, creating a scalloped (wavy) outline around them.

The attached gingiva The attached gingiva lies between the free gingiva at free gingival groove coronally to the alveolar mucosa at the mucogingival junction. The attached gingiva becomes wider as a patient ages

The attached gingiva is widest in the incisor and molar regions ranging from 3.3 to3.9 mm on the mandible and 3.5 to 4.5 mm on the maxilla. The attached gingiva is narrowest in premolar region about 1.8 mm on mandible and 1.9 mm on maxilla. The width of the attached gingival is not measured on the palate since clinically it is not possible to determine where the attached gingival ends and the palatal mucosa begins.

In health, the attached gingiva is pale or coral pink. The attached gingiva is of a firm texture, resilient and tightly bound to the underlying bone therefore, it is immobile in relation to underlying tissue. The attached gingiva may be pigmented, the pigmentation occurs more frequently in dark-skinned individuals. The pigmented areas of the attached gingiva may range from light brown to black. In health, the surface of the attached gingiva may have a dimpled appearance similar to the skin of an orange peel. This dimpled appearance is known as stippling. The stippling is varies greatly from individual to individual about 40% of adults. Stippling is caused by the presence of the connective fibers that attach the gingival tissue to the cementum and bone.

The function of attached gingiva The attached gingiva allows the gingival tissue to withstand the mechanical forces created during activities such as mastication, speaking, and tooth brushing. The attached gingiva prevents the free gingiva from being pulled away from the tooth when tension is applied to the alveolar mucosa.

Interdental gingiva is the portion of the gingiva that fills the area between two adjacent teeth apical to the contact area.

Papilla is the two interdental gingiva, one facial and other lingual. The papilla consists: The lateral borders and tip of an interdental papilla are formed by the free gingival from the adjacent teeth. The center portion of the interdental papilla is formed by the attached gingival.

The col is valleylike depression in the portion of the interdental gingival that lies directly apical to the contact area, and disappear when the adjacent teeth are not in contact or if the gingival has receded. The interdental gingival prevents the food from becoming packed between the teeth during mastication.

Gingival sulcus is the space between the free gingival and the tooth surface. V-shaped, shallow space around the tooth. The depth of a clinically normal gingival sulcus is from 1-3 mm, by using a periodontal probe.

Histology of the gingival Gingival epithelium The gingival epithelium is a specialized stratified squamous epithelium that functions well in the wet environment of the oral cavity. The gingival epithelium is similar to skin.

Oral epithelium Sulcular epithelium Junctional epithelium

Oral epithelium: epithelium that covers the outer surface of the free and attached gingival which extends from the crest of the gingival margin to the mucogingival junction. The epithelium may be keratinized or parakeratinized. The junction of the oral epithelium with the connective tissue has a wavy interface that has epithelial ridges.

Sulcular epithelium: epithelial lining of the gingival sulcus; it extends from the crest of gingival margin to the coronal edge of the Junctional epithelium. The epithelium is nonkeratinzed epithelium. The epithelium is permeable allowing fluid to flow from the gingival connective tissue into the sulcus(gingival cervicular fluid). The flow of gingival cervicular fluid is slight in health and increase in disease. In health, The junction of the Sulcular epithelium with the connective tissue has a smooth interface without epithelial ridge.

Junctional epithelium: epithelium that forms the base of the sulcus of the sulcus and joins the gingival to the tooth surface. The length of junctional epithelium about 0.71-1.35 mm, and the thickness of junctional epithelium is about 15-30 cells thick at the coronal zone that attached highest on the crown of the tooth and tapers to 4-5 cells thick at the apical zone. Junctional epithelium is a thin, nonkeratinzed epithelium. In health, The junction of the junctional epithelium with the connective tissue has a smooth tissue (no wavy junction). The junctional epithelium attaches the gingival to the enamel and /or the cementum of the tooth, thus providing a seal at the base of the gingival sulcus or periodontal pocket, and provides a protective barrier between the plaque biofilm and the connective tissue of the periodontium.

Gingival connective tissue The gingival connective tissue of the free and attached gingival provides solidity to the gingival and attaches the gingival to the cementum of the root and the alveolar bone. The gingival connective tissue is also called lamina propria. The gingival connective tissue has an abundance of extracellular matrix and few cells. Cells comprise 5% of the gingival connective tissue, including fibroblast, and immune cells such as neutrophils, macrophages, and lymphocytes.

The extra cellular matrix consists protein fibers account about 55%-65% of the gingival connective tissue, most of them collagen fibers that form a dense network of strong, ropelike cables that secure and hold the gingival connective tissue together. Gellike material between the cells makes up about 30%-35% of the gingival connective tissue which helps to hold the tissue together. Gellike material between the cells makes up about 30%-35% of the gingival connective tissue, which helps to hold the tissue together.

Periodontal ligament

The periodontal ligament is a layer of soft connective tissue that covers the root of the tooth and attaches it to the bone of the tooth socket. The periodontal ligament is composed of fibers bundles. The fibers of the ligament attached on one side to the root cementum and on the other side to the alveolar bone of the tooth socket.

The functions of the periodontal ligament are: A. Supportive function: major function 1. Attaches the tooth to its bony socket. 2. Suspends the tooth in its socket, separating it from the socket wall, so that the root does not collide with the bone during mastication. B. Sensory function: the periodontal ligament is supplied with nerve fibers that transmit tactile pressure (such as a tap with dental instrument against tooth) and pain sensations. C. Nutritive function: the periodontal ligament is supplied with blood vessels that provide nutrients to the cementum and bone. D. Formative function: the periodontal ligament contains cementoblasts (cementum builders) that produce cementum throughout the life of the tooth, while the osteoblasts (bone builders) maintain the bone of the tooth socket. E. Resorptive function: in response to severe pressure, cells of the periodontal ligament (osteoclasts) can produce rapid bone resorption and, sometimes, resorption of cementum.

MICROSCOPIC ANATOMY OF PERIODONTAL LIGAMENT Cells. The cells of the periodontal ligament are mainly fibroblasts with some cementoblasts and osteoblasts.

Extracellular Matrix. The extracellular matrix of the periodontal ligament is similar to the extracellular matrix of other connective tissue. This rich gellike substance contains specialized connective fibers. Fiber Bundles. The fiber bundles of the periodontal ligament are a specialized connective tissue that surrounds the root of the tooth and connects it with the alveolar bone. These fibers are the largest component of the periodontal ligament.

In health, the periodontal ligament surrounds the entire root of the tooth and fills the space between the root and the bony tooth socket. The thickness of the periodontal ligament ranges from 0.05 to 0.25 mm depending on the age of the patient and the function of the tooth.

Fiber Bundles of the Periodontal Ligament Principal Fiber Groups of the periodontal ligament. These fiber bundles are classified into five groups based on their location and orientation.

Alveolar crest fiber group: extend from the cervical cementum, running downward in a diagonal direction, to the alveolar crest. This fiber group resists horizontal movements of the tooth.

Horizontal fiber group: located apical to the alveolar crest fibers Horizontal fiber group: located apical to the alveolar crest fibers. They extend from the cementum to the bone at right angles to the long axis to the root. This fiber group resists horizontal pressure against the crown of the tooth.

Oblique fiber group: located apical to the horizontal group Oblique fiber group: located apical to the horizontal group. They extend from the cementum to the bone, running in a diagonal direction. This fiber group resists vertical pressures that threaten to drive the root into its socket.

Apical fiber group: extend from the apex of the tooth to the bone Apical fiber group: extend from the apex of the tooth to the bone. This fiber group secures the tooth in its socket and resists forces that might lift the tooth out of the socket.

Interradicular fiber group (seen only in multirooted teeth): extend from the cementum in the furcation area of the tooth to the interradicular septum of the alveolar bone. These fiber groups help to stabilize the tooth in its socket.

Sharpey's Fibers The ends of the periodontal ligament fibers that are embedded in the cementum and alveolar bone are known as Sharpey's fibers.

The attachment of the fiber bundles occurs when the cementum and bone are forming. As cementum forms, the tissue hardens around the ends of the periodontal fibers (Sharpey's fibers) surrounding them with cementum. The same process occurs during bone formation. As the bony wall of the tooth socket hardens, it surrounds the ends of the periodontal fibers with bone. The ends of the fiber bundles become trapped in the bone that forms around them.