Extra oral Anatomical landmarks Anatomical structure 1. Nasolabial Sulcus Description A crease that extends laterally and downwards from the ala of the nose to the corners of the mouth that becomes more prominent with aging. Prosthetic value Affected by: – Proper positioning of anterior teeth. – Proper establishment of occlusal vertical dimensions. – Thickness of the denture flange. 2. Mentolabial Sulcus Runs from side to side horizontally between the lower lip and the chin. Its curvature indicates the character of the maxillomandibular relationship. • Obtuse in class I • Acute in class II • Flat in class III 3. Nasolabial Angle Angle between columella of nose & philtrum of lip Normally, approximately 90 as viewed in profile 4. Philtrum A diamond shaped area at the Affected by center of the upper lip and – Proper positioning of anterior base of the nose. teeth. – Thickness of the denture flange. – loss of teeth and resorption of the labial alveolar boneflattened 5. Vermillion Border It is the transitional epithelium between the mucous membrane of the lips and the skin. Affected by – Proper positioning of anterior teeth. – The bulk of the orbicularis oris muscle. – loss of teeth and resorption of labial alveolar bone orbicularis oris loses its support and drops inward (palatally)  diminution Anatomic Landmarks 1 of amount of vermillion border showing on the upper lip and relative fullness of the lower lip. – Denture should support the mouth angle. – Lack of proper support of the upper lip and a reduced vertical dimensionangular cheilitis that is fissuring and inflammation of the angle of the mouth as a result of a continuous wetting from saliva 6. Angle of the Mouth It is the point of meeting between the upper and lower lip at corners of the mouth 7. Modiolus Located at the meeting place of the buccinator and other facial muscles near the angle of the mouth. 8. Interpupillary line An imaginary line running between the two pupils of the eyes when the patient is looking straight forward. – Aids in orientation of the anterior occlusal plane of artificial teeth. – This parallism allows vertical force transmission to the supporting tissues. Any deviation from this parallism will place non vertical forces which are damaging to the tissues. 9. Ala-tragus line (Camper’s Line) An imaginary line running from the ala of the nose to the tip of tragus of the ear. – Aids in orientation of the posterior occlusal plane of artificial teeth. – This parallism allow the masticatory force to be directed at right angle to the ridge 10. Canthus tragus line Imaginary line running from outer canthus of the eye to the tragus of the ear It is used to arbitrarily to locate the mandibular axis of the condyle – With the loss of teeth, the modiolus is displaced giving the appearance of an edentulous person (sunken cheek). – The buccal surface of the premolar region of the lower denture must be thin to avoid the modiolus lifting the denture. Anatomic Landmarks 1 Intra oral Anatomical landmarks I- Maxilla A- Border (limiting) structures that limit the periphery of the denture • These are the sites that will guide us in having an optimum extension of the denture so as to engage maximum surface area without encroaching upon the muscle actions • Encroaching upon these structures dislodgement of the denture and/or soreness of the area • While failure to cover the areas up to the limiting structure decreased retention stability and support. Anatomical structure 1. Labial frenum 2. Labial vestibule 3. Buccal frenum Description Fold of mucous membrane that may be single or multiple extending from the mucous lining of the lip towards the crest of the ridge on the labial surface. Extends on both sides from the labial frenum to the buccal frenum. Folds or folds of mucous membrane that vary in size and position, and extends from the buccal Prosthetic value Labial notch should be provided in the denture to facilitate functional movement of the frenum and avoid ulceration. The reflection of the mucous membrane superiorly determines the height of the denture flange. Denture borders should be functionally trimmed to avoid dislodgment of the denture during function. Anatomic Landmarks 1 4. Buccal vestibule 5. Hamular notch 6. Vibrating line of the soft palate mucous membrane reflection area to the crest of the residual ridge. The space distal to the buccal frenum. Bounded externally by the cheek and internally by the residual ridge. –Buccinator muscle will not displace the denture (horizontal direction of the fibers). –Thickness of the distal end of the buccal flange must accommodate the coronoid process (displace denture). - The size of the buccal vestibule varies with:  contraction of the buccinator muscle  coronoid process of the mandible during opening – Posterior palatal border of the denture should extend from hamular notch on one side to the hamular notch on the other side passing through vibrating line of soft palate. – Its mucous membrane contains thick submucosa with loose areolar connective tissue that help to achieve posterior palatal seal. Soft palate has two parts; – Posterior palatal seal anterior immovable and should be created on the posterior movable. compressible immovable – Vibrating line (Ah tissues of soft palate. line) is an imaginary line –Its width follows soft palate lying between the curvature. movable and immovable parts of the soft palate. – Vibrating line extends from one hamular notch to the other, 2 mm posterior to fovea palatinae following palatal contour. Notch located between maxillary tuberosity anteriorly and the pterygoid hamulus posteriorly.