This document discusses the anatomical landmarks of the mandibular denture bearing area. It identifies the limiting structures that determine the extent of dentures, such as the labial and buccal frenums and vestibules. The supporting structures are the primary load bearing areas and include the buccal shelf area and residual alveolar ridge. Relief areas like the mylohyoid ridge and mental foramen should be relieved in dentures due to fragile tissue or risk of trauma under constant load. The average available denture bearing area in the mandible is 14cm2, significantly less than the maxilla's 24cm2, making the mandible less capable of resisting occlusal forces.

1. PRESENTED BY
ROSHALMARIA THOMAS
IV/II
MANDIBULAR ANATOMICAL
LANDMARKS

2. • THE ANATOMY OF EDENTULOUS RIDGES IN THE
MAXILLA AND MANDIBLE IS VERY IMPORTANT
FOR THE DESIGN OF THE COMPLETE DENTURE
• THE TOTAL AREA OF SUPPORT FROM THE
MANDIBLE IS SIGNIFICANTLY LESS THAN FROM
THE MAXILLA.
• THE AVERAGE AVAILABLE DENTURE BEARING
AREA FOR AN EDENTULOUS MANDIBLE IS
14cm2 , WHEREAS FOR EDENTULOS MAXILLA
IT IS 24cm2. THEREFORE THE MANDIBLE IS
LESS CAPABLE OF RESISTING OCCLUSAL
FORCES THAN THE MAXILLA.

3. ANATOMICAL LANDMARKS OF
MANDIBULAR DENTURE BEARING
AREA
 LIMITING STRUCTURES-they determine and
confine extent of dentures
 SUPPORTING STRUCTURES- these are the load
bearing areas- They show minimal ridge resorption
even under constant load
 RELIEF AREAS- these areas resorb under constant
load or contain fragile structures within

5. Limiting structures
 Labial frenum
 Labial vestibule
 Buccal frenum
 Buccal vestibule
 Lingual frenum
 Alveolingual sulcus
 Retromolar pad
 Pterygomandibular raphe

6.  Labial frenum
 Fibrous band
 Muscles incisivus and orbicularis oris
 Active
 Labial vestibule
 Space between residual alveolar ridge and lips
 Length and thickness of labial flange-influences lip support
and retention
 Buccal frenum
 Overlies depressor anguli oris
 Fibers of buccinators attached
 Buccal vestibule
 Extends- posteriorly from buccal frenum to retromolar pad
region
 Residual alveolar ridge on one side and buccinators on other
 Influenced by action of masseter

8.  Lingual frenum
 Should be relieved
 High lingual frenum is called tongue tie –affects stability
 Alveololingual sulcus
 Extends from lingual frenum to retromylohyoid curtain
 Divided into 3 parts- anterior, middle and posterior
 Anterior region- from lingual frenum to premylohyoid fossa
 Flange is shorter anteriorly and should touch the floorof the mouth
whentip of tongue touches upper incisors
 Middle- extends from premylohyoid fossa to distal end of
mylohyoid ridge
 Shallower due to prominence of mylohyoid ridge and action of
mylohyoid muscle
 Posterior- retromylohyoid fossa
 Typical S form of lingual sulcus
 Retromolar pad
 Posterior seal of mandibular denture
 Pear shaped
 Triangular keratinized soft pad of tissue at distal end of ridge
 Bounded posteriorly by tendons of temporalis, laterally by
buccinators and medially by pterygomandibular raphe and

10. SUPPORTING STRUCTURES
 Buccal shelf area
 Residual alveolar ridge

11.  Buccal shelf area
 Area between buccal frenum and anterior border of
masseter
 Width increases as resorption continues
 Lies at right angles to occlusal forces- primary
stress bearing area
 Residual alveolar ridge
 Edentulous mandible may become flat with concave
denture bearing surface
 In such cases, structures attaching on lingual side of ridge
attach over the ridge
 Due to resorption mandible inclines outwards and becomes
progressively wider

13. Relief area
 Mental foramen
 Genial tubercle
 Mylohyoid ridge
 Mandibular tori.

14.  Mylohyoid ridge
 Runs along lingual surface of mandible
 Anteriorly lies close to inferior border of mandible,
posteriorly lies flush along the ridge
 Thin mucosa- easily traumatized- hence should be
relieved
 Undercut present under the ridge
 Mental foramen
 Between first and second premolar region
 Relieved- as pressure may cause paresthesia
 Genial tubercles
 Pair of bony tubercles
 Present anteriorly on lingual side of body of mandible
 Due to resorption may become increasingly prominent-
denture usage difficult