Periodontium – Gums Anatomy

Periodontium – Gums Anatomy

Gums are a specialized part of the oral mucosa that covers the alveolar bone and surrounds the neck of the teeth. The gingival papilla is the gum located between teeth. The gums consist of the following main parts: free gingiva, attached gingiva, gingival sulcus, and junctional epithelium.

Functions of the gums:

• Help teeth adhere and stabilize in the alveolar bone.

• Connect the teeth to each other.

• Create continuity of the epithelium covering the oral cavity.

• Prevent bacterial invasion.

Gross Anatomy:

• The gum surface can be keratinized or semi-keratinized.

• The basal layer of the gum epithelium has sharp, pointed waves that interdigitate with the connective tissue papillae, creating an orange peel appearance (gingival grooves) on the gum surface.

Free gingiva:

• The gingival margin surrounds the neck of the tooth, the enamel-cement junction. The surface is smooth and adheres loosely to the tooth.

• 50% of the free gingiva is separated from the attached gingiva by the “free gingival groove,” which is a shallow, V-shaped depression.

• The free gingiva has a width that varies from 1-1.6mm depending on age and is the soft wall of the gingival sulcus.

• The free gingiva can be mobile; it can be separated from the tooth surface using a probe.

Attached gingiva:

• This part continues from the free gingiva and extends to the junction of the gingiva and the alveolar mucosa. The outer surface is adjacent to the alveolar mucosa on both jaws. The inner surface on the lower jaw is adjacent to the oral floor mucosa.

• The attached gingiva is pink with an orange peel appearance, while the alveolar mucosa is dark red. The attached gingiva is firmly attached to the alveolar bone by a dense network of collagen fibers. In the cervical region, the fibers are attached to the root cementum, passing through the alveolar bone crest.

• The epithelium of the attached gingiva is an extension of the oral mucosa epithelium.

Gingival sulcus:

• This is a small, V-shaped groove, the point of contact between the free gingiva and the tooth surface.

• The gingival sulcus surrounds the tooth like the free gingiva and is an extension of the free gingiva into the tooth neck.

• The normal gingival sulcus depth is 2-3mm.

• Clinically, the depth of the gingival sulcus is an important parameter for diagnosing periodontal disease.

Junctional epithelium:

• This adheres to the tooth surface in a strip extending from the base of the gingival sulcus to the enamel-cement junction with a width of 2.5mm.

• The junctional epithelium is derived from the enamel organ.

Microscopic Anatomy:

Oral epithelium:

• Contains 4 cell layers: basal layer, prickle cell layer, granular layer, and keratinized layer.

Connective tissue of the gum:

• Makes up a large proportion of the free and attached gingiva.

• Contains a high proportion of collagen fibers, arranged in bundles, with many cells.

• Represents the papillary layer.

Regeneration and repair capacity of gum tissue:

• Epithelium:

• Complete cell replacement cycle: 5-7 days.

• Gum epithelium regeneration: progresses from the tip to the gingival margin.

• Gum excision procedure: new connective epithelium grows back within 2 weeks.

• Renewal rate is higher than oral epithelium.

• Connective tissue:

• Replacement rate is very fast.

• Collagen density and renewal rate are functions of the concentration of fibroblasts and their activity.

Protective mechanisms of gum tissue:

• Gingival fluid:

• Secreted from the connective tissue of the gums, diffuses through the gum epithelium into the gingival sulcus.

• Average rate of 0.1mg/3 minutes, and increases during wound healing during treatment.

• Plays a protective role by flushing away bacteria and foreign substances.

• Leukocytes in the gingival sulcus:

• These are polymorphonuclear leukocytes present in healthy gums.

• They are concentrated in the connective tissue adjacent to the gingival sulcus to enter the sulcus.

• Include polymorphonuclear leukocytes (majority) and monocytes.

• Even in healthy gums, leukocytes are capable of phagocytosis and bacterial killing, forming an effective mechanism against bacterial plaque.

• Saliva:

• Has protective properties and maintains the oral mucosa in a normal physiological state.

• Role of saliva in periodontal disease:

• Affects the formation, development, and metabolism of plaque.

• Formation of calculus, periodontal disease, and caries are dependent on saliva.

• Dry mouth increases gingivitis and caries in the cervical region of teeth.

• Gum nerves – blood vessels:

• Gum circulation: In the upper jaw, there are branches of the posterior superior alveolar artery, sublingual artery, submental artery, and lymphatic vessels that run parallel to the arteries.

• Lymphatics: In the upper jaw, they drain into the deep cervical nodes, while in the lower jaw, they drain into the submental lymph nodes, submandibular nodes, and cervical nodes.

• Nerves: The upper jaw is supplied by branches of the posterior, middle, inferior, anterior, orbital, nasal, and palatine nerves. The nerve fibers accompany the blood vessels, have myelin sheaths, and form bundles.

Junctional epithelium:

• This is a gingival sulcus lining that connects the junctional epithelium to the free gingiva.

Clinical signs of healthy gum tissue:

• Color: Pale pink or brown-black, varies depending on the individual, thickness of the epithelium, and presence of pigment cells.

• Gum surface: Orange peel appearance (40%).

• Tonus: In the free gingiva, this is due to the presence of excess collagen fibers.

• Sulcus depth: When probing, normal is <3mm.

• Bleeding: Usually no bleeding or minimal bleeding when probing.