Oral Cavity and Pharynx pt1

Oral Cavity and Pharynx

Learning Objectives

  • Define and pronounce key terms.

  • Locate and identify divisions and surface landmarks of the oral cavity.

  • Integrate clinical considerations for surface anatomy into patient care.

  • Outline divisions of the pharynx and identify them on a diagram.

  • Integrate study of surface anatomy of visible pharynx divisions into patient care.

Oral Cavity Properties

  • Dental professionals must be knowledgeable about the oral cavity and pharynx.

  • Understanding boundaries, terminology, and divisions is crucial for examination and assessment.

  • Unit 2 discusses oral tissue development and disturbances.

  • Unit 3 covers orofacial tissue histology and surface features.

  • Unit 4 addresses dental anatomy.

Oral Cavity Divisions

  • The oral cavity is divided into:

    • Oral vestibules.

    • Jaws with alveolar processes and teeth.

    • Oral cavity proper (palate, tongue, floor of the mouth).

  • Practice finding surface landmarks using a mirror and textbook for improved examination skills.

  • Understanding the boundaries aids in understanding the divisions.

    • Anterior boundary: Lips

    • Posterior boundary: Pharynx

    • Lateral boundaries: Cheeks

    • Superior boundary: Palate

    • Inferior border: Floor of the mouth

  • Orientational terms:

    • Facial: Structures closest to the facial surface.

    • Labial: Facial structures closest to the lips.

    • Buccal: Facial structures closest to the inner cheek.

    • Lingual: Structures closest to the tongue.

    • Palatal: Lingual structures closest to the palate.

Oral Vestibules

  • Horseshoe-shaped spaces between lips/cheeks and teeth.

  • Maxillary and mandibular vestibules.

  • Lined by oral mucosa.

  • Labial mucosa: Pink to darker pink lining inner lips.

  • Buccal mucosa: Pink to darker pink lining inner cheeks, continuous with labial mucosa; may vary in color with darker skin tones.

  • Vestibular fornix: Deepest part of vestibule where labial/buccal mucosa meets alveolar mucosa.

  • Mucobuccal fold: Where thicker labial/buccal mucosa meets thinner, redder alveolar mucosa; may appear darker red in people with darker skin tones.

  • Labial frenum: Fold of tissue at the midline between labial and alveolar mucosa on dental arches.

  • Physiologic pigmentation: Localized areas possible in tissues, common with darker skin tones.

  • Buccal fat pad: Adipose tissue in posterior oral vestibule, acts as a cushion during mastication (chewing).

  • Parotid papilla: Raised tissue area opposite the maxillary second molar, protects the parotid duct opening.

Clinical Considerations with Oral Vestibules

  • Fordyce spots (or granules):

    • Small yellowish bumps on labial and buccal mucosa.

    • Deeper deposits of sebum from misplaced sebaceous gland tissue.

    • Harmless but become more pronounced with age due to tissue thinning.

  • Linea alba:

    • Whiter ridge of calloused tissue on buccal mucosa at the occlusal plane.

    • Hyperkeratinization where maxillary and mandibular teeth meet.

    • Excess can indicate orofacial parafunctional habits like clenching or grinding (bruxism).

Jaws, Alveolar Processes, Teeth

  • Maxilla and mandible surround oral cavity proper.

  • Maxilla:

    • Two maxillary bones sutured at the midline.

    • Non-movable articulation with facial and skull bones.

    • Body contains the maxillary sinus.

  • Mandible:

    • Single bone with movable articulation at temporomandibular joint (TMJ).

    • Heavy horizontal part inferior to teeth is the body.

  • Alveolar process:

    • Bony extension of maxilla and mandible containing tooth sockets (alveoli).

    • Teeth attached via periodontal ligament (PDL), allowing slight movement.

  • Tooth structure:

    • Crown: From cementoenamel junction (CEJ) to biting surface, covered by enamel and dentin, overlying pulp.

    • Root: Covered by cementum, attaches to PDL and alveolus.

    • Cervix (neck): Junction between crown and root at CEJ.

    • Root apex: Farthest part of the root from the crown.

  • Coronal: Structures related to the tooth crown.

  • Cervical: Structures related to the cervix.

  • Apical: Structures related to the root apex.

Dental Arches

  • Maxillary arch: Contains maxillary teeth.

  • Mandibular arch: Contains mandibular teeth.

  • Primary teeth (children):

    • Incisors, canines, and molars.

  • Permanent teeth (adults):

    • Incisors, canines, premolars, and molars.

  • Anterior teeth: Incisors and canines.

  • Posterior teeth: Molars and premolars.

  • Maxillary tuberosity: Tissue-covered rounded area of bone posterior to the last maxillary tooth.

  • Retromolar pad: Dense tissue pad posterior to the last mandibular tooth.

Clinical Considerations with Alveolar Process

  • Exostoses:

    • Atypical finding on the facial surface of the maxillary alveolar process.

    • Localized developmental growths of bone covered in oral mucosa.

    • Possible hereditary etiology, associated with occlusal trauma.

    • Single or multiple, unilateral or bilateral raised hard areas in the premolar to molar region.

    • Appear radiopaque on dental imaging.

    • May interfere with imaging, restorative treatment, and periodontal therapy.

  • Mandibular torus (tori):

    • Atypical finding on the lingual surface of the mandibular arch.

    • Developmental growth of bone with possible hereditary etiology, associated with grinding (bruxism).

    • Usually bilateral in the premolar area, can be lobulated or nodular.

    • Covered in oral mucosa, vary in size, slow-growing, and asymptomatic.

    • Appear radiopaque on dental imaging.

    • May interfere with speech, homecare, dental imaging, and dental prosthesis.

Gingival Tissue

  • Surrounds teeth and covers alveolar processes.

  • Soft tissue gums or gingivae composed of oral mucosa.

  • Four anatomic zones:

    • Attached gingiva.

    • Marginal gingiva.

    • Interdental gingiva/papilla.

    • Gingival sulcus.

  • Attached gingiva:

    • Tightly adheres to alveolar process around tooth roots.

    • Includes maxillary tuberosity and retromolar pad.

    • Demarcation (mucogingival junction) between attached gingiva and alveolar mucosa.

  • Marginal gingiva (free gingiva):

    • Forms a cuff above the neck of the tooth.

    • Transparent, pink to darker pink (with darker skin tones).

    • Free gingival groove separates it from attached gingiva.

    • Free gingival crest at the most coronal part.

  • Interdental gingiva:

    • Gingival tissue between adjacent teeth.

    • Individual extension is an interdental papilla.

  • Gingival sulcus:

    • Shallow V-shaped space faced by the circular inner surface of gingival tissue.

  • Increased melanin deposit may be a typical finding in attached gingiva, especially at the base of interdental papillae.

Fauces and Palate

  • Fauces:

    • Opening from the oral cavity into the pharynx.

    • Formed laterally by anterior and posterior faucial pillars.

    • Palatine tonsils located between these pillars.

  • Palate:

    • Roof of the mouth, separates oral and nasal cavities.

  • Hard palate:

    • Bony, whiter, anterior arched part.

    • No mucogingival junction; mucosa blends with palatal attached gingiva.

  • Incisive papilla: Small bulge lingual to anterior teeth.

  • Median palatine raphe: Midline ridge from incisive papilla towards the pharynx.

  • Palatine rugae: Firm, irregular ridges radiating from incisive papilla and raphe.

  • Soft palate:

    • Yellower, looser, softer posterior part.

  • Uvula: Midline muscular structure hanging from the posterior margin of the soft palate.

  • Pterygomandibular fold: Extends from hard/soft palate junction to mandible, just posterior to the last mandibular tooth; covers a fibrous structure and separates cheek from pharynx.

Clinical Considerations with Palate

  • Palatal torus: Atypical finding on the midline of the hard palate, similar to mandibular torus; may interfere with dental prosthetic treatment.

  • History of cleft palate: Developmental disturbance that needs to be noted due to its impact on dental care.

Tongue

  • Prominent feature of the oral cavity proper.

  • Pharyngeal part (base):

    • Posterior one-third, attaches to the floor of the mouth, within the oral part of the pharynx.

  • Oral part (body):

    • Anterior two-thirds, lies within the oral cavity proper.

  • Apex: Tip of the tongue.

  • Division into posterior and anterior parts is important due to differences in innervation, structure, and embryonic development.

  • Dorsal surface:

    • Median lingual sulcus: Midline depression corresponding to a fibrous structure.

    • Lingual papillae: Raised structures of specialized mucosa; some contain taste buds.

  • Filiform lingual papillae: Slender, threadlike, whitish papillae giving the dorsal surface its texture.