1. this action will displace the mandible denture to anterior direction
2. I. Extra-Oral landmarks
   1. 1- Inter-pupillary line
      1. - Imaginary line running between the two pupils of the eye when the pt. is looking straight forward.
      2. - Establishing the anterior Occlusal plane of the artificial teeth of the denture.
   2. 2- Ala-tragus line (Camper's line)
      1. - Imaginary line running from the Inferior border of the ala of the nose to the superior border of the tragus of the ear.
      2. - Establishing the posterior Occlusal plane of the artificial teeth of the denture.
   3. 3- Canthus-tragus line
      1. - Imaginary line running from the outer canthus of the eye to the superior border of the tragus of the ear.
      2. - Locating the position of the condyles.
   4. 4- Naso-labial sulcus
      1. - Depression that extends from the ala of the nose in a downward and lateral direction to the corner of the mouth.
      2. - it become more prominence with aging and it restored by:
         1. 1- vertical dimension
         2. 2- anterior teeth positioning
         3. 3- labial flange
      3. - After extraction of teeth it becomes accentuated and should be restored by complete denture.
   5. 5- Vermillion border
      1. - The transitional epithelium between the mucous membrane of the lip and the skin.
      2. - After extraction disappears in the upper lip and becomes accentuated in the lower& should be restored by a complete denture.
   6. 6- Mento-labial sulcus
      1. - Depression runs horizontally between the lower lip and chin.
      2. - It determines the Angle of Classification:
      3. 1- Angle class [I]: Normal ridge relationship.
      4. 2- Angle class [II[: Retruded mandibular position.
      5. 3- Angle class [III]: Protruded maxillo-mandibular relation ship.
   7. 7- Philtrum
      1. - Diamond-shaped area between the center of the upper lip and the base of the nose.
      2. - After extraction of teeth it becomes flattened and should be restored by a complete denture.
   8. 8- Modiolus
      1. - The point of meeting of facial muscle fibers.
      2. - After extraction of teeth it becomes downwards and should be restored by a complete denture.
   9. 9- Angle of the mouth
      1. - Point of meeting between the upper and lower lip.
      2. - (Angular Chilitis): Inflammation and ulceration as a result of:
      3. 1- Prolonged edentulism.
      4. 2- ↓ vertical dimension of complete denture.
      5. 3- Vitamin B deficiency.
3. II. Intra-Oral landmarks
   1. limiting structure
      1. in maxilla
         1. Labial frenum
         2. •Labial vestibule
         3. •Buccal frenum
         4. •Buccal vestibule
         5. •Hamular notch
            1. posterior border of the denture
            2. Between the bony tuberosity and hamulus
            3. “Soft displaceable tissue”, for comfort and retention
            4. Use the head of your mirror to palpate the notch & mark with an indelible marker
         6. •Posterior palatal seal area
            1. how can we located ?
      2. in mandible
         1. 2- External oblique ridge
            1. - Bony ridge running downward and forward from ramus to reach mental foramen.
            2. - It is a limiting structure to the complete denture and not extend to it.
         2. 5- Retromolar pad
            1. - Pear-shaped area located distal to the lower 3rd molar.
            2. - Shock absorbent.
            3. - Gives retention not support.
            4. - Determine the level of the Occlusal plane.
   2. supporting structure
      1. in maxilla
         1. primary stress bearing area
            1. The horizontal portion of the hard palate to the midline
            2. Slopes of residual alveolar ridge
            3. - The portion of the alveolar process & it's soft tissue covering that remains after extraction.
            4. - It covers by a dense connective tissue fibers so, it can be act as a 1ry stress bearing area.
            5. type
            6. Flat
            7. “V”-shape
            8. “U”-shape
            9. Rounded
         2. 2ry stress bearing area
            1. Rugae area
            2. - It is irregular elevations radiates from the midline of the anterior part of the palate.
            3. - 2ry stress bearing area.
            4. - Prevent forward movement of the denture.
            5. - If it is sensitive or prominent it should be relived.
            6. Maxillary Tuberosity
            7. - Bony prominence located posterior to the upper 3rd molar.
            8. - Aid in support, retention and stability of the complete denture.
            9. - When it is large:
            10. 1- Relieved.
            11. 2- Modify the path of insertion. (unilateral enlargement).
            12. 3- Surgical removal.
      2. in mandible
         1. primary stress bearing area
            1. Buccal shelf area
            2. - Bony area extends between the external oblique ridge and the residual ridge.
            3. - Used as 1ry stress bearing area:
            4. 1- Perpendicular to the vertical masticatory force.
            5. 2- Formed from compact bone.
            6. 3- provide support.
         2. 2ry stress bearing area
            1. residual ridge
            2. - The portion of the alveolar process& it's soft tissue covering that remains after extraction.
            3. - Don't used as 1ry stress bearing area → Covered by movable fibrous connective tissue.
            4. - Don't Provide stability or support.
   3. relief structures
      1. in maxilla
         1. Incisive papilla
            1. - Pear-shaped elevation present in the midline behind the 2 centrals.
            2. - After extraction of teeth it migrates to the crest of the ridge.
            3. - It should be relieved to avoid the burning sensation of the palate.
         2. •Mid-palatine raphe
            1. - The mucoperiostium that covers the median palatine suture.
            2. - When it is prominent it should be relieved.
            3. - Lack of relief cause:
            4. 1- rocking of the denture due to bone resorption.
            5. 2- Tissue ulceration.
            6. 3- Mid-line denture fracture.
         3. •Fovea palatine
            1. - Two openings of minor salivary glands present in both sides of the midline posterior to junction of hard and soft palate.
            2. - It determines the posterior extension of the upper complete denture to be 2mm posterior to it.
         4. Torus palatinus
            1. - Bony prominence present at both sides of the midline of the palate.
            2. - It should be:
            3. 1- Relieved.
            4. 2- Surgical removal.
         5. •Crest of the residual alveolar ridge
      2. in mandible
         1. 4- Mental foramen
            1. - It's located on the Buccal surface of the mandible between the roots of 1st and 2nd premolar.
            2. - Lack of relief → numbness of the lower lip.
         2. 6- Torus mandibularis
            1. - Bony prominence located at the inner surface of premolar area.
            2. - It should be:
            3. 1- Relieved.
            4. 2- Surgical removal.
         3. 7- Internal oblique ridge (Mylohyoid ridge)
            1. - Irregular bony ridge of median surface of the mandible which the Mylohyoid muscle attached.
            2. - It should be relieved during complete denture construction.
         4. 8- Genial tubercle (Mental spine)
            1. - Two bony projections present at the median surface of mandible at midline of each side of symphesis.
            2. - Represent the attachment of geniohyiod and genioglossus muscles.
            3. - If it's prominent, it should be relieved.
4. III. Muscles producing mandibular movement, and their effect on denture border
   1. A. muscles of mastication
      1. Masseter
         1. image080.jpg
         2. 1- forceful contraction of the masseter muscle force the buccinator muscle in medial direction in the area of retromolar bad ( this action can be recorded in the final impression )
         3. 2- the distal portion of the maxillary buccal flange may also be affected when the masseter exerted heavy closing pressure
      2. Temporalis
         1. 1-The Extension of temporal tendon into the retremolar pad may effect the posterior border of the mandibular denture
         2. 2- The attachment of the muscle on the coronoid process of the mandible affects the buccal aspect of the maxillary denture border by forcing the buccinator muscle to encroach on the buccal vestibule during lateral movement.
      3. Medial pterygoid muscle
         1. the attachment to the maxillary tuberosity may affect the denture border in the hamular notch area
      4. Lateral Pterygoid muscle
         1. The lateral pterygoid muscle has no effect on the denture border
   2. B. muscles of mandibular depression
      1. Geniohyoid muscle
         1. very little direct effect unless anterior residual ridge resorption formation is severe
            1. if the muscle interferes with border formation, it may surgical detached and repositioned at lower level
      2. Mylohyoid muscle
         1. The action of the mylohyoid muscle influences almost the mandibular lingual denture border.
   3. C. muscles of facial expression
      1. image078.jpg
         1. Orbicularis oris muscle
            1. the position and action of this muscle is dependent on proper:
            2. 1- anterioposterior position of the anterior teeth
            3. 2- thickness of the labial flanges of both denture
            4. 3- vertical dimension and occlusion
         2. buccinator muscle
            1. The superior portion of the muscle influences the hight of distobuccal flange of the maxillary denture.
            2. contraction of the buccinator pulls the maxillary and mandibular buccal frenae backward.
            3. in the buccal shelf area the mandibular denture rest on fibers of the buccinator. however because the fiber run anteroposteriorly. contraction does not unseat the denture
         3. mentalis muscle
            1. functional movement of mentalis are important in determining the:
            2. lenght
            3. position
            4. contour
            5. of the labial flange of the mandibular denture, particularly when the residual ridge in its anterior region is nonexistent
5. recognizable anatomic structure used as a point of refrence