Fiche de révision : Oral Cavity Dental Anatomy

📋 Course Outline

1. Oral Cavity Boundaries and Divisions
2. Vestibular Mucosa and Landmarks
3. Jaws, Teeth, and Dental Arches
4. Gingiva and Alveolar Variations
5. Oral Cavity Proper and Palate
6. Tongue Anatomy and Papillae
7. Floor of the Mouth
8. Clinical Variations and Follow-Up
9. Pharyngeal Divisions

📖 1. Oral Cavity Boundaries and Divisions

🔑 Key Concepts & Definitions

• Oral cavity : The upper end of the digestive system, extending from the lips posteriorly to the area behind the palatine tonsils and inferiorly from the floor of the mouth to the hard and soft palates.
• Vestibule : The horseshoe-shaped space between the lips and cheeks externally and the teeth and their supporting soft tissues internally, with maxillary and mandibular subdivisions.
• Oral cavity proper : The internal part of the mouth enclosed anteriorly by the maxillary and mandibular arches and opening posteriorly into the pharynx through the fauces.

📝 Essential Points

📌 The vestibule is the space between the lips or cheeks and the teeth, whereas the oral cavity proper is the area surrounded by the teeth or alveolar ridges and extending posteriorly to the palatine tonsils.

• The lips form the anterior boundary, the cheeks form the lateral boundaries, the palate forms the superior boundary, the floor of the mouth forms the inferior boundary, and the pharynx forms the posterior boundary of the oral cavity.

📖 2. Vestibular Mucosa and Landmarks

🔑 Key Concepts & Definitions

• Mucobuccal fold : The mucobuccal or mucolabial fold is the area where the mucosa of the cheeks or lips turns toward the gingival tissue.
• Alveolar mucosa : Movable, generally reddish oral mucosa lying against the alveolar bone and containing underlying blood vessels.
• Labial frenum : A midline fold of tissue between the labial mucosa and alveolar mucosa on the upper and lower dental arches, with the upper frenum usually more pronounced.
• Vermilion zone : The reddish transitional tissue between the facial skin and the oral mucosa of the lips.
• Philtrum : The midline indentation in the skin of the upper lip derived from the embryonic medial nasal processes.

★ Must-know

• The vestibule has the lips as its anterior border, the cheeks as its lateral border, and the anterior border of the mandibular ramus covered by soft tissue as its posterior border.

Further detail

• The cheek is formed largely by the buccinator muscle and is covered by skin externally and mucous membrane internally.

• The parotid papilla lies on the buccal mucosa opposite the maxillary second molar and protects the opening of the parotid duct.

📖 3. Jaws, Teeth, and Dental Arches

🔑 Key Concepts & Definitions

• Alveolar process : The bony extension of the maxilla and mandible that contains the tooth sockets, or alveoli.
• Tooth crown : The crown is the erupted part of a mature tooth and contains an outer enamel layer, an underlying dentin layer, and the soft pulp internally.

★ Must-know

📌 The maxilla is fixed to facial and skull bones and contains a body and four processes, whereas the mandible is a single bone that articulates movably with the temporal bones at the temporomandibular joints.

• The periodontal ligament attaches each tooth to the bony surface of its alveolus while allowing slight tooth movement and supporting the tooth.

📌 Primary teeth include incisors, canines, and molars, whereas permanent teeth include those tooth types plus premolars.

Further detail

• Dentin continues around the pulp in the roots, while cementum forms the outermost layer of each root.

• Incisors and canines are anterior teeth, whereas molars and premolars, when present, are posterior teeth.

💡 Memory Hook

Maxilla is fixed; mandible moves

📖 4. Gingiva and Alveolar Variations

🔑 Key Concepts & Definitions

• Gingiva : Firm, pink oral mucosa that surrounds the teeth in their alveoli and covers the alveolar processes.
• Attached gingiva : Gingival tissue that is tightly adherent to the alveolar process around the tooth roots.
• Marginal gingiva : Marginal or free gingiva forms a cuff around the tooth above its neck and is separated from attached gingiva by the free gingival groove.
• Interdental papilla : An individual extension of interdental gingiva occupying the space between adjacent teeth.
• Gingival sulcus : The rounded space faced by the circular inner surface of gingival tissue around each tooth.

📖 5. Oral Cavity Proper and Palate

🔑 Key Concepts & Definitions

• Fauces : The opening from the oral cavity proper into the pharynx, bounded laterally by the anterior and posterior faucial pillars.
• Hard palate : The white, anterior, arched, bony part of the palate that forms the anterior roof of the mouth.
• Soft palate : The yellowish, loose, soft posterior part of the palate, from whose posterior margin the muscular uvula hangs.

📝 Essential Points

• The incisive papilla is a small tissue bulge at the anterior hard palate immediately lingual to the anterior teeth, and the incisive foramen lies beneath it.

• The incisive foramen transmits nasopalatine nerves and blood vessels to the mucosa lingual to the maxillary incisors and is an injection site for anesthetizing the anterior palate between the canines.

• Palatine rugae are firm, irregular ridges radiating posteriorly from the incisive papilla and median palatine raphe.

• The median palatine raphe is a midline tissue ridge extending from the incisive papilla to the uvula over the bony fusion of the palate.

📖 6. Tongue Anatomy and Papillae

🔑 Key Concepts & Definitions

• Sulcus terminalis : An inverted V-shaped groove on the posterior dorsal tongue that separates the body from the base.

★ Must-know

📌 The oral part or body of the tongue forms the anterior two-thirds and lies in the oral cavity proper, whereas the pharyngeal part or base forms the posterior one-third.

• There are 10 to 14 circumvallate papillae with taste buds arranged along the anterior side of the sulcus terminalis.

Further detail

📌 Filiform papillae are the most abundant slender, whitish papillae and lack taste buds, whereas fungiform papillae are reddish and mushroom-shaped.

• The foliate papillae are vertical ridges on the lateral surface of the tongue, while deep lingual veins and the plica fimbriata are visible on its ventral surface.

• The foramen cecum is a small pit at the posterior point of the sulcus terminalis, and the lingual tonsil is an irregular lymphatic tissue mass farther posteriorly on the tongue base.

📖 7. Floor of the Mouth

🔑 Key Concepts & Definitions

• Lingual frenum : An anterior midline fold of tissue connecting the ventral tongue to the floor of the mouth.
• Sublingual fold : A ridge on each side of the floor of the mouth that forms a V-shaped arrangement from the lingual frenum toward the tongue base.
• Sublingual caruncle : A small papilla at the anterior end of each sublingual fold containing openings of the submandibular and sublingual ducts.

📝 Essential Points

• The submandibular duct is also called Wharton duct, and the sublingual duct is also called Bartholin duct.

📖 8. Clinical Variations and Follow-Up

🔑 Key Concepts & Definitions

• Exostosis : A localized developmental bony growth covered by oral mucosa, usually on the facial surface of the maxillary alveolar process in the premolar-to-molar region, appearing radiopaque on radiographs.
• Mandibular torus : A developmental bony growth on the lingual surface of the mandibular arch that may have hereditary and bruxism-related associations.
• Palatal torus : An uncommon developmental bony variation located on the midline of the hard palate and similar in presentation and etiology to mandibular tori.
• Fordyce granules : Common small yellowish elevations on labial and buccal mucosa caused by deeper deposits of sebum from misplaced or trapped sebaceous gland tissue.
• Linea alba : A horizontal white ridge of hyperkeratinized buccal mucosa at the occlusal plane where the maxillary and mandibular teeth contact.

📝 Essential Points

• A change in a patient's oral tissue or associated structure should be documented in the patient record and appropriately followed up, because individual change may indicate clinical significance.

📖 9. Pharyngeal Divisions

🔑 Key Concepts & Definitions

• Pharynx : A muscular tube serving both respiratory and digestive functions and providing the deeper continuation of the oral cavity proper.

📝 Essential Points

• The nasopharynx lies superior to the soft palate and continues with the nasal cavity, the oropharynx lies between the soft palate and laryngeal opening, and the laryngopharynx is the inferior division near the laryngeal opening.

📊 Synthesis Tables

Oral Cavity Divisions

Palatal Structures