1. MAXILLA
   1. Limiting Structures
      1. Labial frenum
         1. Contains no muscle fibres
         2. Accommodated by a groove in labial flange of maxillary denture
      2. Labial vestibule
         1. Contains no muscle fibres
         2. But is indirectly effected by Orbicularis Oris muscle
      3. Buccal frenum
         1. Band of tissue that overlies the Levator anguli Oris/ Caninus muscle
      4. Buccal vestibule
         1. Bounded Laterally : cheek Medially : RAR
         2. Area of the denture which will fill this space is known as Buccal Flange
      5. Hamular notch
      6. Posterior palatal seal(vibrating line)
      7. Fovea palatina
   2. Supporting Structures
      1. Primary stress-bearing areas
         1. Hard palate
            1. Mucosa is keratinized throughout
            2. Posterolaterally, submucosa contains glandular tissue
            3. Horizontal area lateral to midline provides primary support
         2. Postero-lateral slopes of residual alveolar ridge (RAR)
            1. Denture bearing area of the ridge is covered by : KERATINISED MUCOSA
      2. Secondary stress-bearing areas
         1. Rugae
         2. Maxillary tuberosity
   3. Relief areas
      1. Incisive papilla
         1. It overlies the incisive foramen
            1. nasopalatine nerves & vessels arise
         2. Relief over the papilla should be provided to avoid pressure on nerve & blood supply
      2. Cuspid eminence
      3. Mid-palatine raphe
         1. It is relieved to - prevent pressure on palatal region
         2. Mid palatine suture area is covered by thin submucosa & mucosa layer is in contact with the underlying bone.
         3. The soft tissue is non resilient & is relieved to avoid trauma from denture base
2. OTHER KEY POINTS
   1. Massetric Notch
      1. In distobuccal corners of mandibular denture
      2. Action of Masseter on buccinator
   2. Limits of lower denture
      1. Anterior region
         1. Origin of Genioglossus muscle & sublingual gland
      2. Molar region
         1. Mylohyoid muscle
      3. Distal most part
         1. Palatoglossus & superior constrictor
   3. Average denture bearing area
      1. Maxilla
         1. 24 cm2
      2. Mandible
         1. 12.25cm2 / 14cm2
3. MANDIBLE
   1. Limiting structures
      1. Labial frenum
         1. Fibrous band, Active in nature
         2. Influenced by Orbicularis Oris & Incisivus muscles
      2. Labial vestibule
      3. Buccal frenum
      4. Buccal vestibule
      5. Lingual frenum
      6. Alveololingual sulcus
         1. Extends from lingual frenum to retromylohyoid curtain
         2. Anterior region
            1. extends from lingual frenum to premylohyoid fossa
         3. Middle region
            1. extends from premylohyoid fossa to distal end of mylohyoid ride
         4. Posterior region
            1. Retro-mylohyoid fossa is present here
            2. Denture flange in this region should turn laterally upwards towards ramus to fill up the fossa
            3. complete the typical S-form of lingual flange of lower denture
      7. Retromolar pads
         1. Relatively stable landmark
         2. Should be covered by lower denture for perfect border seal
         3. Boundaries
            1. Posteriorly - Temporalis tendon
            2. Laterally - buccinator
            3. Medially - pterygomandibular raphe & superior constrictor muscle
      8. Mylohyoid ridge
         1. Irregular bony crest on lingual surface of mandible
         2. The ridge is near Inferior border of mandible in the incisor region & terminates near 3rd molar area
         3. Border of lingual flange may extend below mylohyoid line if it slopes towards the tongue
      9. External oblique ridge
   2. Supporting structures
      1. Buccal shelf area
         1. Boundaries
            1. Medially - crest of the ridge
            2. Distally - retromolar pad
            3. Laterally - external oblique ridge
      2. Residual alveolar ridge
   3. Relief areas
      1. Crest of RAR
      2. Mental foramen
         1. Lies on external surface
            1. Between 1st & 2nd premolar area
         2. In severe resorption of the ridge - denture should be relieved over the foramenn
            1. To prevent pressure on the mental nerves and vessels
      3. Genial tubercles
         1. Paired bony tubercles on Anteriorly lingual side of body of mandible
            1. Due to resorption, may become very prominent making denture usage difficult
      4. Torus mandibularis