Extra-Oral Examination Overview

Study Notes

Extra-Oral Examination

Nasolabial Sulcus: Crease extending from the ala of the nose to the mouth corner, becoming more prominent with age. Important for anterior tooth positioning, occlusal vertical dimension, and denture flange thickness.
Mentolabial Sulcus: Horizontal crease between the lower lip and chin. Its curvature helps determine the maxillomandibular relationship.
Nasolabial Angle: The angle between the nose's columella and the lip's philtrum. Normally close to 90 degrees in profile.
Philtrum: Diamond shape area at the center of the upper lip and the base of the nose. Flattens with tooth loss and resorption.
Vermillion Border: The transitional epithelium between the lip's mucous membrane and the skin. Its appearance is influenced by the orbicularis oris muscle, labial alveolar bone, tooth position, and denture flange thickness.
Angle of the Mouth: The denture should support the mouth angle. Insufficient support or reduced vertical dimension can lead to angular cheilitis (fissuring and inflammation). Helps determine the width of the six anterior teeth.
Modiolus: Located at the junction of the buccinator and other facial muscles near the mouth angle. Can be displaced with tooth loss, making the cheek appear sunken.
Ala-Tragus Line (Camper's Line): Imaginary line from the nose's ala to the ear's tragus. Aids in orienting the posterior occlusal plane of artificial teeth. Allows for perpendicular force transmission to the ridge, improving stability and reducing tissue stress.
Interpupillary Line: Imaginary line between the pupils when looking straight ahead. Aids in orienting the anterior occlusal plane of artificial teeth. Aligning the artificial teeth with this line ensures vertical force transmission, preventing damage to supporting tissues.
Canthus-Tragus Line: Imaginary line from the outer eye canthus to the ear tragus. Used to locate the mandibular condyle axis.

Grouping of Landmarks

Limiting Structures: Guide optimal denture extension, engaging maximum surface area while avoiding muscle interference. Encroachment can lead to denture dislodgement or soreness.
Denture Bearing Areas (Supporting Structures): Areas that bear the weight of the denture. Failure to cover these areas can result in reduced retention, stability, and support.

Maxilla's Anatomical Landmarks

Border Structures (Limiting):
- Labial Vestibule: The space between the lips and the teeth.
- Buccal Vestibule: The space between the cheeks and the teeth.
- Maxillary Tuberosity: Located behind the last molar and forms a bony prominence.
- Hamular Notch: A depression located below the maxillary tuberosity, where the pterygoid hamulus can be felt.
- Pterygomaxillary Notch: Located between the maxillary tuberosity and the pterygoid hamulus.
Denture Bearing Areas (Supporting):
- Palatal Rugae: Ridges on the hard palate near the front.
- Incisive Papilla: A small elevation on the hard palate, located directly behind the central incisors.
- Maxillary Ridge: The bony ridge formed after tooth extraction.
- Hard Palate: The bony roof of the mouth, which supports the denture.

Mandible's Anatomical Landmarks:

Border Structures (Limiting):
- Labial Vestibule: The space between the lower lip and the teeth.
- Buccal Vestibule: The space between the cheeks and the teeth.
- Retromolar Pad: A soft tissue pad located behind the last molar.
- Mylohyoid Ridge: A bony ridge located on the inner aspect of the mandible.
Denture Bearing Areas (Supporting):
- Mandibular Ridge: Bony ridge formed after tooth extraction.
- Genial Tubercles: A small bony elevation located on the inner aspect of the mandible.
- Mylohyoid Groove: A groove located on the inner surface of the mandible that accommodates the mylohyoid muscle.
- Retromolar Pad: A soft tissue pad located behind the last molar.