NORMAL CLINICAL FEATURES OF THE

GINGIVA

By

Dr. Marcel Hallare

COLORCOLOR

The color of the attached and marginal gingivae is generally described as coral pink and is produced by the vascular supply, the thickness and degree of keratinization of the epithelium, and the presence of pigment-containing cells

PHYSIOLOGIC PHYSIOLOGIC PIGMENTATION PIGMENTATION

(MELANIN)(MELANIN)

Melanin, a non-hemoglobin-derived brown pigment is responsible for the normal pigmentation of the skin, gingiva, and remainder or the oral mucous membrane

SIZESIZE

Size of gingiva corresponds to the sum total of the bulk of cellular elements and their blood supply

Alteration in size is a common feature of gingival disease

CONTOURCONTOUR

The marginal gingiva envelops the teeth in collar-like fashion and follows a scalloped outline on the facial and lingual surfaces

It forms a straight line along teeth with relatively flat surfaces

On teeth with pronounced mesiodistal convexity of teeth in labioversion, the normal arcuate contour is accentuated and the gingiva is located further apically

On teeth in linguoversion, the gingiva is horizontal and thickened

SHAPESHAPE

The shape of the interdental gingiva is governed by the contour of the proximal tooth surfaces and the location and shape of gingival embrasures

CONSISTENCYCONSISTENCY

The gingiva is firm and resilient and, with exception of the movable free margin, tightly bound to the underlying bone

SURFACESURFACE TEXTURETEXTURE

The gingiva presents a textured surface like that of an orange peel and is referred to as being stippled

The attached gingiva is stippled; the marginal gingiva is not

The central portion of the interdental papillae is usually stippled, but the marginal borders are smooth

Stippling varies with age. It is absent in infancy, increases until adulthood , and frequently begins to disappear in old age.

Microscopically, stippling is produced by alternate rounded protuberances and depressions in the gingival surface

The papillary layer of the connective tissue projects into the elevations, and both the elevated and the depressed areas are covered by stratified squamous epithelium

Stippling is a form of adaptive specialization or reinforcement for function. It is a feature of healthy gingiva, and reduced or loss of stippling is a common sign of gingival disease

When the gingiva is restored to health following treatment, the stippled appearance returns

The surface texture of the gingiva is also related to the presence and degree of epithelial keratinization

Keratinization is considered to be a protective adaptation to function. It increases when the gingiva is stimulated by toothbrushing

PERIODONTALPERIODONTAL LIGAMENTLIGAMENT The periodontal ligament is the

connective tissue structure that surrounds the root and connects it with bone

It is continuous with connective tissue of the gingiva and communicates with the marrow spaces through vascular channels in the bone

Dense fibrous connective tissue Dense fibrous connective tissue attaching the tooth to the attaching the tooth to the alveolar bonealveolar bone

Function—to support the tooth in Function—to support the tooth in the alveolus & to maintain the the alveolus & to maintain the physiologic relation between the physiologic relation between the cementum and bonecementum and bone

NORMAL MICROSCOPIC NORMAL MICROSCOPIC FEATURESFEATURES

The most important elements of the periodontal ligament are the principal fibers, which are collagenous, arranged in bundles, and follow a wavy course when viewed in longitudinal section

Terminal portions of the principal fibers that insert into cementum and bone are termed Sharpey’s fibers

PRINCIPAL FIBERSPRINCIPAL FIBERS Transseptal Group – extend interproximally

over the alveolar crest and are embedded in the cementum of adjacent teeth

Alveolar Crest Group – extend obliquely from the cementum just beneath the Junctional epithelium to the alveolar crest and their function is to counterbalance the coronal thrust of the more apical fibers, thus helping to retain the tooth within the socket and resists

Horizontal Group – their fibers extend at right angles to the long axis of the teeth from the cementum to the alveolar bone and function is similar to alveolar crest group

Oblique Group – largest group in the periodontal ligament, extends from the cementum in a coronal direction obliquely to the bone and bears the brunt of vertical masticatory stresses and transform them into tension on the alveolar bone

Apical Group – they radiate from the cementum to the bone at the fundus of the socket and not present in incompletely formed roots

Other FibersOther Fibers

Elastic fibers - this group of fibers are scarce and are confined to the loose connective tissue surrounding neurovascular channels

Oxytalan - is found interspersed among the collagen fibers, and is morphologically similar to those in gingiva and run in an occluso-apical direction associated with blood vessels and nerve fibers. They are found more often on the cemental than on the bony side of the ligament

Indifferent fiber plexus - appears to course parallel to the root surface, forming a loose intersecting network and may also be incorporated into the mineralized matrices

CELLSCELLS

The main function of periodontal ligament cells is to maintain the normal organization of the fiber system by synthesizing new fibers and remove old ones

Generally the cellular density in periodontal ligament is greatest in young individuals and decrease with age

Cellular density also increases with heavy function and decreases with lack of function

FIBROBLASTFIBROBLAST

They make up the major cellular population of the ligament

principal cells of the periodontal ligament

Their function is to synthesize collagen, which aggregates into fibrils and fibers extracellularly

CEMENTOPROGENITOR CEMENTOPROGENITOR AND OSTEOPROGENITOR AND OSTEOPROGENITOR CELLSCELLS CEMENTOBLASTS – Are observed

during active deposition of cellular cementum

OSTEOBLASTS – Found in the peripheral part of the periodontal ligament adjacent to bone and seen where alveolar bone is deposited

OSTEOCLASTS and ODONTOCLASTS –Osteoclasts work with osteoblasts to remodel existing alveolar bone. Odontoclasts can resorb mineralized dental tissue, including cementum

EPITHELIAL CELLS – They are commonly found in the ligament close to cementum. They originate from Hertwig’s epithelial root sheath

Undifferentiated mesenchymal cells OR PROGENITOR CELLS -- -- These cells have a perivascular location within 5 micrometers of blood vessels and a source of new cells for the periodontal ligament

MACROPHAGES –In the ligament are important defense cells because of their phagocytic activity and mobility (take up bacteria, dead cells and foreign bodies)

LEUCOCYTES – Individual leukocytes, specially small lymphocytes and plasma cells may appear in periodontium when it is stressed by disease

VASCULAR SUPPLYVASCULAR SUPPLY

Compared with other connective tissues, the periodontal ligament is exceptionally well vascularized, which reflects the high rate of turnover of its cellular constituents

Its main blood supply is from the SUPERIOR AND INFERIOR ALVEOLAR ARTERIES

NERVESNERVES The periodontal ligament contains both The periodontal ligament contains both

sensory and autonomic nerve endingssensory and autonomic nerve endings The sensory nerve endings are able to The sensory nerve endings are able to

identify pain and pressureidentify pain and pressure The mechanoreceptors for pressure are The mechanoreceptors for pressure are

extremely sensitive and are able to detect extremely sensitive and are able to detect minute particles between occluding tooth minute particles between occluding tooth surfaces surfaces

The autonomic innervation that originates The autonomic innervation that originates from the superior cervical ganglion is from the superior cervical ganglion is primarily responsible for the control of primarily responsible for the control of smooth muscles associated with the smooth muscles associated with the periodontal vasculatureperiodontal vasculature

FUNCTIONS OF THE FUNCTIONS OF THE PERIODONTAL PERIODONTAL

LIGAMENTLIGAMENT PHYSICAL FORMATIVE NUTRATIVE AND SENSORY

PHYSICAL PHYSICAL

Transmission occlusal forces to the bone

attachment of teeth to bone maintenance of the gingival tissues in

their proper relationship to the teeth resistance to the impact of occlusal

forces (shock absorption) provision of “soft tissue casing” to

protect the vessels and nerves from injury by mechanical forces

FORMATIVEFORMATIVE

Periodontal ligament serves as the periosteum for cementum and bone

Cells of the periodontal ligament participate in the formation and resorption of cementum and bone which occur in physiologic tooth movement

In the accommodation of the periodontium to occlusal forces and in the repair of injuries

NUTRATIVENUTRATIVE

The periodontal ligament supplies nutrients to the cementum, bone, and gingiva by way of the blood vessels and provides lymphatic drainage

SENSORYSENSORY

The innervation of the periodontal ligament provides proprioceptive and tactile sensitivity which detects and localizes external forces acting upon the individual teeth and serves an important role in the neuromuscular mechanism controlling the masticatory musculature