Anatomical Landmarks Mandibular prosthodontics

mandibular anatomical landmarks is a key point of studying oral cavity . i study about it & make this ppt .

1. MANDIBULAR ANATOMICAL LANDMARKS SUBHRAKANTI PANDIT ANKESH KUMAR

2. INTRODUCTION The anatomy of the edentulous ridges in the maxilla and mandible is very important for the design of the complete denture. The total area of support of the mandible is much less than the maxilla. The average available denture bearing area for an edentulous mandible is 14cm 2 , whereas for edentulous maxilla it is 24cm 2 . Therefore the mandible is less capable of resisting occlusal forces than the maxilla ..

3. MANDIBULAR ANATOMICAL LANDMARKS 1. Limiting Structures- They determine the confine extent of dentures. 2 . Supporting Structures- These are the load bearing areas-They show minimal ridge resorption even under constant load. 3. Relief areas- These areas resorb under constant load or contain fragile structure within .

4. 1 1. Labial Frenum 1. Genial 2. Labial Vestibule tubercle 3. Buccal Frenum 2. Torus 4. Buccal Vestibule mandibularis 5. Lingual Frenum 3. Mental 6. Alveolingual foramen Sulcus 7. Retromolar Pads Buccal shelf Crest of 8. Pterygomandibular area alveolar ridge Raphe LIMITING STRUCTURES SUPPORTING STRUCTURES RELIEF AREAS PRIMARY STRESS BEARING SECONDARY STRESS BEARING

5. LANDMARKS IN MOUTH LANDMARKS IN IMPRESSION 1. Labial frenum 2. Labial vestibule 3. Buccal frenum 4. Buccal vestibule 5. Residual alveolar ridge 6. Retromolar pad 7. Pterygomandibular raphae 8. Retromylohyoid fossa 9. Lingual tuberosity 10. Alveolingual sulcus 11. Lingual frenum 12. Buccal shelf area 1. Labial notch 2. Labial flange 3. Buccal notch 4. Buccal flange 5. Alveolar groove 6. Retromolar fossa 7. Pterygomandibular notch 8. Retromylohyoid eminence 9. Lingual tubercular fossa 10. Lingual flange 11. Lingual notch 12. Buccal flange resting on buccal shelf area

6. LIMITING STRUCTURE A.LABIAL FRENUM Active bond Fibrous bond Extension- Labial aspect of residual ridge to lip Muscle attachment-Orbicularis- oris * LABIAL FRENUM

7. Clinical significance During the final impression this frenum is recorded as labial notch. It is recorded in the human mouth due to the movement of lower lip toward, upward and inward. Labial notch(In the final impression)

8. B . LABIAL VESTIBULE It is the space between lips and alveolar process, bordered by the buccal frenum and divided at the labial frenum Muscle attachment-Orbicularis muscle and the incisive labi -inferior Mentalis muscle is an active in this area LABIAL VESTIBULE

9. Clinical significance In the final impression the labial vestibule is recorded as labial flange It is recorded in the patient mouth by sucking movement LABIAL FLANGE (in the final impression)

10. C . BUCCAL FRENUM It is the fibrous bond Separates labial and buccal vestibule Muscle attachment- Depressor anguli oris

11. Clinical significance It is recorded in the patient mouth by the movement of cheek. The cheek is lifted outward, upward, backward and forward. Buccal frenum is recorded in the final impression as Buccal notch. BUCCAL NOTCH

12. Clinical significance It is recorded in the patient mouth by the movement of cheek. The cheek is lifted outward, upward, backward and forward. Buccal frenum is recorded in the final impression as Buccal notch. BUCCAL NOTCH

13. D. BUCCAL VESTIBULE Extends from buccal frenum till retromolar pad region. Bound by residual ridge on one side and buccinator on the other. Space influenced by action of masseter muscle. Muscle attachment-Buccinator anteriorly and pterygomandibular raphe posteriory .

14. Clinical significance In the final impression this buccal vestibule is recorded as buccal flange. To record the buccal flange we have to instruct the patient to open the mouth wide and then to close against the resting force of your finger and the cheek is moved outward , upward and inward . BUCCAL FLANGE

15. E. LINGUAL FRENUM Mucous mambrane fold seen on elevation of the tongue. Base of tongue to supragenial tubercle . LINGUAL FRENUM

16. Clinical significance Recording process – The patient is instructed to wipe his lower lip from side to side with the tongue tip .

17. F. ALVEOLINGUAL SULCUS Space between residual alveolar ridge and the tongue. Anterior region Extension-Lingual frenum to the mylohyoid ridge curves above the sulcus. The middle region Extension-From the pre-mylohyoid fossa to the distal end of the mylohyoid ridge. Lingual flange should slope medially. The posterior region Retro- mylohyoid fossa present here . ALVEOLINGUAL SULCUS

18. Clinical significance Recording process Patient is asked to protrude the tongue out –this gives the length of the flange. Patient is asked to touch the cheeks with tongue- this gives width of the flange. ALVEOLINGUAL SULCUS

19. G. RETROMOLAR PAD AREA It defines the posterior limit. Triangular soft pad of tissue at distal end of lower ridge. Pear shaped pad area-Keratinized residual scar of the third molar. It is not a favorable denture bearing area. Associated with-Buccinator(from buccal shelf),superior constrictor, temporalis and firmly bond masticatory mucossa

20. The junction between the pear shaped pad and the retromolar pad demarcates the distal border of the properly extended mandibular complete denture.

21. H. PTERIGOMANDIBULAR RAPHE The pterigomandibular raphe or ligament originates from the pterigoid hamulus of medical pterygoid plate and attaches to distal end of myloid ridge. Raphe is a tendinous insertion of two muscle. The superior constrictor is inserted posteriorlly. Buccinator is anteriolaterally inserted .

22. 2 . SUPPORTING STRUCTURES A. BUCCAL SHELF AREA * It is the area between buccal frenum and anterior border of masseter muscle BOUNDARIES *MEDIALLY : Slopes of residual ridge *LATERALLY : External oblique line *ANTERIORLY : Buccal frenum *POSTEROIRLY : Retromolar pad

23. MUSCLE ATTACHMENT Buccinator- muscle fibres attaches inferiorly to buccal shelf. Fibres run longitudnally anteroposteriorly permitting to rest on the muscle without displacement.

24. MUSCLE ATTACHMENT Buccinator- muscle fibres attaches inferiorly to buccal shelf. Fibres run longitudnally anteroposteriorly permitting to rest on the muscle without displacement.

25. B. CREST OF ALVEOLAR RIDGE * Crest of residual alveolar ridge is covered by fibrous connective tissue . *The slopes of residual alveolar ridge have thin plate of cortical bone . The slopes of the ridge are at an acute angle to occlusal forces. * Hence it is considered as secondary stress bearing area .

26. Since the crest of ridge has cancellous bone, it is not favourable as primary stress bearing area. Lack of muscle attachment. It undergoes rapid resorption CLINICAL SIGNIFICANCE : Any movable soft tissue overlying the ridge should not be compressed while making impression.

27. It is an exit point of nasopalatine nerves and vessels. It should be relieved , if not, the denture will compress the nerve or vessels and lead to necrosis Of the distributing areas and paresthesia of anterior palate . … . Relief Areas A . Mylohyoid Ridge B. Mental Foramen C. Genial Tubercle D. Torus Mandibualris 3. RELIEF AREAS

28. A . MYLOHOID RIDGE Attachment for the mylohyoid muscle. Running along the lingual surface of the mandible. Anteriorly : The ridge lies close to the inferior border of the mandible. Posteriorly : It lies close to the residual ridge. Clinical Significance : Covered by the thin mucosa which may be traumatized by denture base hence it should be relieved.

29. MYLOHOID RIDGE

30. B. MENTAL FORAMEN Lies on the external surface of the mandible in between the 1 st and the 2 nd premolar region. It should be relieved specially in case it lies close to the residual alveolar ridge due to ridge resorption to prevent paresthesia . Clinical significance It should be relieved in these areas as pressure over the nerve passing through it can get compressed by denture base leading to numbness of lower lip

31. C. GENIAL TUBERCLE Area of muscle attachment (Genioglossus And Geniohyoid) Lies away from the crest of the ridge. Prominent in resorbed ridges therefore adequate relief to be provided. Clinical significance They only become relevent in the denture when there is excessive resorption of residual ridge .

32. GENIAL TUBERCLE

33. D . TORUS MANDIBULARIS Abnormal bony prominence. Bilaterally on the lingual side near the premolar area. Covered by thin mucosa so it should be relieved. Small tori may only require relief in the dentine. Large tori require removal before a denture can be fabricated . Clinical significance If small and not prominent should be relieved. if prominent and bulged should be surgically removed .

34. TORUS MANDIBULARIS

35. THANK YOU