Anatomy of the Edentulous Ridges Chapter 3 PDF

ANATOMY OF THE EDENTOULOUS RIDGES chapter 3 Marketing Department Mon. Feb. 21. 2018  ANATOMY OF THE EDENTOULOUS RIDGES chapter 3 Anatomy of Maxilla Anatomical Landmarks In Relation to Complete Denture: Extraoral Intraoral lan...

ANATOMY OF THE EDENTOULOUS RIDGES chapter 3 Marketing Department Mon. Feb. 21. 2018  ANATOMY OF THE EDENTOULOUS RIDGES chapter 3 Anatomy of Maxilla Anatomical Landmarks In Relation to Complete Denture: Extraoral Intraoral landmarks landmarks  EXTRA-ORAL LANDMARKS 1. INTERPUPILLARY LINE. 2. ALA-TRAGUS LINE. 3. NASIOLABIAL SULCUS. 4. MODIOLUS. 5. PHILTRUM. 6. VERMILLION BORDER. 7. ANGLE OF THE MOUTH. 8. MENTOLABIAL SULCUS.  IMAGINARY LINES INTERPUPILLARY LINE ALA-TRAGUS ANTERIOR LINE OCCLUSAL PLANE POSTERIOR OCCLUSAL PLANE  Anatomical landmarks of the face Nasolabial sulcus Philtrum Modiolus Mentolabial sulcus Angle of the mouth Reduced amount of shown vermillion border  Landmarks restored by proper lip support Naso – Labial sulcus it is a depression extending from the side of the nose downwards and backwards Becomes deeper with age and with loss of teeth Philtrum diamond shape at center of the upper lip becomes flat with loss of teeth Modiolus Vermillion border the transitional epithilium between the mucous membrane of the lip and the skin. becomes reduced in size  labiomental sulcus A depression that runs horizontally between the lower lip and the chin. Importance: give indication about the relationship between mandible and maxilla  MENTOLABIAL SULCUS MENTOLABIAL SULCUS MENTOLABIAL SULCUS ACUTE (CLASS II ,ANGLE) SLIGHTLY OBTUSE (CLASS I, ANGLE) In Angle class I: The normal ridge relationship, the mento-labial sulcus shows a gentle curvature which represent an obtuse angle In Angle class II: Retruded mandibular position, the mento-labial sulcus presents an acute angle in which the lower lip is folded towards the chin In Angle class III: Protruded maxillo-mandibular relationship, the mento-labial sulcus may form an angle of almost 180 Commissures angle of the mouth. a. becomes inflamed with prolonged edentulous state due to dripping of saliva Treated by construction of a denture at the proper V.D.O. b. It lies opposite to the canines for determination of the canine line. Angular chelities Before After CHANGES THAT HAPPEN AFTER TOOTH LOSS. 1. Resorption of the alveolar supporting bone. 2. Lack of support of the facial muscles. 3. Chin nose approximation.  Intraoral Landmarks Maxilla Mandible Supporting structures Supporting structures & & Limiting structures Limiting structures MAXILLARY SUPPORTING STRUCTURES 1.RESIDUAL ALVEOLAR RIDGE Residual Alveolar Ridge 1. It is usually broad, rounded and covered with dense fibrous c.t. 2.MAXILLARY TUBEROSITY Tuberosity Tuberosity The most posterior part of the alveolar ridge; it lies distal to the position of the last molar. It is a bulbous mass of mucous membrane that overlies a bony tuberosity. The maxillary tuberosity is because it is considered a primary stress-bearing area surgery must be considered when the tuberosity is extremely large and compromises the clearance necessary for opposing dentures.  3.INCISIVE PAPILLA 1. Pear shape elevation of soft tissue at midline just palatal to upper centrals. 2. It covers the incisive foramen Through which nasopalatine nerves and vessels pass. 3. In some cases due to the excessive bone resorption, the papilla may lie on the crest of the ridge. 4. The incisive papilla should be relieved to avoid pressure on the incisive nerves and vessels which might cause burning sensation.  4.MEDIAN PALATINE RAPHE 1. The midline of the hard palate is covered by a thin layer of mucoperiostium , that covers the median palatine suture. 2. It is usually relieved to avoid the rocking of the denture and midline fracture.  5.The Palatine rugae Palatine Rugae 1. irregular shaped elevation of ridges of dense c.t extending laterally from the midline in the anterior one third the hard palate. 2.Thickness of this area affect speech (s) sound.  6.TORUS PALATINUS bony exostosis sometime present middle of the palate.if small → relieved large → surgical excision(has lateral undercut,extend to vibrating line)  7.FOVEA PALATINA Fovea Palatina Fovia Palatina 1. Two small pits or depressions found on sides of midline corresponding to the opening of the ducts of minor salivary gland. 2. The posterior border of the upper denture should be 2 mm posterior to the fovea Palatina.  8.ROOT OF ZYGOMA Buttress Part Of Bone Buttress Part Of Bone 1. It is formed of the lower portion of the zygomatic process of the maxilla (the area above the first molar teeth). 2. It provides excellent resistance to the vertical forces(Support).  Ι-Limiting structures a. Maxillary 1. labial frenum: Definition: a fold of mucous membrane which attaches the upper lip to the mucous membrane of the alveolar ridge. Importance: must be relieved in the denture by making a v-shaped notch opposite to its position to avoid: a. Denture displacement. b. Ulceration of the frenum.  2. Labial vestibule: Definition: it is a reflection of the mucosa of the upper lip to the mucosa of the alveolar process. Importance: control the thickness & the length of the labial flange of the upper denture ……… provides peripheral seal. 3. Buccal frenum: Definition; a fold of the m.m. that varies in size and number Contain muscle fibres of levator anguli oris Importance: should be relieved in the denture by making a v-shaped notch opposite to its position to facilitate its functional movements without: a. denture dispalcement. b. frenum ulceration.  4.Buccal vestibule Reflection of m.m from cheek to alveolar ridge distal to the buccal frenum. Related to buccinator muscle Due to the horizontal direction of buccinator muscle fiber..contraction of this muscle does not displace denture  5. soft palate: Immovable part Movable part Lies adjacent to Lies more the hard palate posterior The junction between them is called The vibrating line (AH line)  Importance: The posterior edge of the upper denture should end at this junction to provide a posterior palatal seal (post dam). The width of this seal is determined by the curvature of the soft palate: a. class1: gentle curvature of the soft palate broad posterior palatal seal area. b. calss2: medium curvature medium width of the posterior palatal seal. c. calss3: sharp curvature narrow posterior palatal seal area.  Posterior palatal seal (post dam) ❑ Posterior palatal seal: it is slight compression (within the physiologic limit) applied by the denture over the resilient soft tissues at the junction between the movable & immovable parts of the soft palate to aid in its retention. ❑ Post-damming: it is the elevation at the posterior border of the maxillary denture.  Objectives of post-damming Prevents the passage of air between the tissues & the denture Prevents food from getting Improves the retention of under the denture the upper denture To provide firm contact between tissues & the posterior border of the denture Compensates for the Eliminates the gagging polymerization shrinkage of reflex by making the the denture at the posterior posterior border of the border. denture less felt by the tongue.  Requirements for an effective posterior palatal seal lie on easily displaceable tissues (into the immovable soft palate). Should be in touch with the soft palate during rest & function to create a valve seal.  6. Pterygo-maxillary notch (hamular notch): Definition: a notch between the maxillary tuberosity anteriorly & the pterygoid hamulus posteriorly. Importance: a line 2 mm buccal to the center of the notch from the hamular notch on one side to that on the other side determines the posterior limit of the upper denture. Can be a possible site of irritation. Thank You