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1. Good Morning

2. HARD PALATE AND SOFT PALATE Presented by : R.Priya Darshini

3. CONTENTS Introduction Development of palate Hard palate Structures within the hard palate Incisive papilla Mid palatine raphe Rugae Greater palatine foramen Fovea palatine Classification of hard palate

4. Soft palate - Palatine aponeurosis - Palatine musculature Tensor veli palatini Levator veli palatini Palatoglossus Palatopharyngeus Musculus uvulae - Classification of soft palate. - House’s classification of palatal throat forms

5. Vascular supply of palate Venous drianage Sensory nerve supply Motor nerve supply. Pathology Conclusion References

6. Introduction PALATE Horizontal structure separating the oral and nasal cavities; the roof of the mouth. Divided in to hard palate (anterior two thirds) and soft palate (posterior one third. Mucoperiosteum covers part of the bony skeleton of the hard palate, whereas Mucous membrane covers the muscular soft palate.

7. Definition Hard Palate : -Bony portion of the roof of the mouth (GPT-8) -The anterior portion of roof of mouth, formed by maxillae and palatine bones and lined by mucous membrane. (TORATORA-Glossary) Soft Palate : -Movable part of palatal anatomy posterior to hard palate (GPT-8) -Posterior portion of roof of mouth, extending from the palatine bones to uvula. It is a muscular partition lined with mucous membrane.(TORATORA-Glossary)

8. DEVELOPMENT OF PALATE Fouth week in utero Primitive oral cavity ( stomodeum ) is bounded by five facial swellings, produced by proliferating zones of mesenchyme lying beneath mandibular and maxillary processes .

9. Fifth week in utero localized thickenings of ectoderm give rise to the nasal and optic placodes . The nasal placodes sink into the underlying mesenchyme , forming two blind-ended nasal pits (the primitive nasal cavities). Proliferation of mesenchyme from the frontonasal process around the openings of the nasal pits produces the medial and lateral nasal processes.

10. Sixth week in utero The primitive nasal cavities are separated by a primary nasal septum and are partitioned from the primitive oral cavity by a primary palate . Both the primary nasal septum and primary palate are derived from the frontonasal process. A –Primitive nasal cavities B – Primary Nasal Septum C – Primary Palate

11. Development of Primary Palate Develops from the deep tissues of the frontonasal process during the deepening of the nasal pit to form the nasal sac. Tissues beneath the nasal sac enlarge & grow inferiorly to form the primary palate. It acquires the triangular shape due to the continuous growth of the maxillary process in a medial direction. A –Primitive nasal cavities B – Primary Nasal Septum C – Primary Palate

12. During the deepening of the nasal sac & the formation of the primary palate, the ectoderm at the depth of the nasal sac proliferates to form a thickened ectodermal plate, the nasal fin. This nasal fin then thins down to a membrane called the “ oro-nasal membrane” The rupture of the oronasal membrane detaches the primary palate from the nasal cavity. The primary palate & central parts of upper lip are one unit at first, then by 8 weeks in utero become separated by the vestibular lamina

13. The secondary palate forms the palate posterior to the incisive fossa that comprises both the hard & the soft palate The inferior medial edges of the maxillary process forms the palatine processes (shelves) at 6 weeks in utero . Development of Secondary Palate

14. The tongue is narrow & high filling all the oro -nasal cavity, so the palatine shelves grow medially & downwards (vertically) on either sides of the tongue

15. The fusion of the palatine shelves occurs first just posterior to the primary palate. From this point, the fusion of the palatine shelves with premaxilla proceeds anteriorly & fusion between palatine shelves proceeds posteriorly . Palatal shelf elevation

16. Fusion also occurs between Palatal shelves & the nasal septum except posteriorly , where the soft palate & uvula remain unattached. The palate then becomes invaded in its anterior 2/3 rd by bone (from premaxillary & maxillary palatal centers) to form the hard palate. The posterior part becomes invaded by muscles to form the soft palate

17. The incisive suture demarcate the union between primary & secondary palate, while palatine raphe demarcate union between 2 palatine shelves.

18. DEVELOPMENTAL DEFECT OF PALATE CLEFT PALATE: Cleft palate is a birth defect characterized by an opening in the roof of the mouth caused by a lack of tissue development.

19. Various theories have been given for its development - Alteration in intrinsic palatal shelf force - Failure of tongue to drop down - Non fusion of shelves - Failure of mesodermal migration - Rupture of cyst formed at the site of fusion.

20. TYPES OF PALATAL CLEFTS

21. HARD PALATE Occupies anterior 2/3rds of the entire palatal area. Rigid and immovable. Boundaries – Anteriorly and laterally by teeth and alveolar ridges. Posteriorly by soft palate.

22. Mucosa – Masticatory mucosa. - keratinised mucosa at varying levels - At the raphae region mucosa directly attached to periosteum - Submucosa present only in the lateral portions with anterior part having adipose tissue and posterior part having minor salivary glands

23. Prosthetic considerations The denture bases rest on the mucous membrane which serve as a cushion between the base and the bone The thickness and consistency of the submucosa are responsible for the soft tissue support of the dentures. The mucous membrane covering the hard palate is firmly attached to the periosteum of maxillary bone by connective tissue of sub mucosa. this compact bone in combination with tightly attached mucous membrane make the palate best able to provide primary support for upper denture.

24. When the sub mucosal layer is thin, will be non resilient and small movements of the denture break the retentive seal. When the submucosal layer is loosely attached to the periosteum or inflamed,the tissue will be displaceable and cause loss of stability.

25. Resistance to resorption of bony hard palate- functioning of tensor veli and levator veli muscles of soft palate may provide sources of tension that counter act the pressure resorption normally expected beneath the denture base. The palatine process of maxilla and horizontal plates of palatine bone resist resorption and is covered by keratinised mucosa and resilient sub mucosa, hence it functions as a primary denture support area.

26. STRUCTURES WITH IN THE HARD PALATE Incisive papillae Mid palatine raphae Rugae Major or anterior palatine foramen Fovea palatinae

27. INCISIVE PAPILLAE Distinct prominence just behind the maxillary central incisors, covering the nasopalatine nerves as they emerge from incisive foramen.

28. – Prosthetic considerations Prosthesis should be relieved in this area to prevent undue pressure. Impingement causes decreased blood supply to anterior palate and nerve irritation with burning sensation.

29. MID PALATINE RAPHAE Hard ridge extending posteriorly from the incisive papillae nearly to soft palate. Mucosal layer directly attached to the underlying bone. Submucosa is absent or very thin. So, tissue covering the mid palatine suture is non resilient.

30. Prosthetic considerations Little or no pressure should be applied to this region Excessive pressure in this area causes pain . Relief should be given in this area for accommodation of the histological nature of the tissue.

31. RUGAE Elevated ridges that radiate transversely from incisive papillae region and anterior part of palatine raphae

32. Prosthetic considerations Shouldn’t be distorted in impression since rebounding tissue tends to unseat the denture. Secondary stress bearing area – b’cos of dense connective tissue underneath this zone. Also as the rugae is set at an angle to the occlusal plane of residual ridges, it also contributes to retention. Resists anterior displacement of denture. In resorbed ridges the anterior mucosa will be flabby due to the rugae and requires relief as there is no bone support

33. GREATER PALATINE FORAMEN Located medial to third molar at the junction of horizontal plate of palatine bone and the alveolus. Bone in this region is notched, and from this the palatine groove extends anteriorly and houses the anterior palatine nerve and blood vessels.

34. Prosthetic considerations Relief is rarely required in the denture base as the nerves and blood vessels are housed in a groove.

35. FOVEA PALATINAE Two small pits seen, one on each side of the mid line. These represent the orifices of the ducts from some of the minor mucous glands of the palate.

36. Location of fovea palatinae : According to Sicher - Located posterior to location of hard palate. Nagle - Posterior limit of hard palate. Fenn - Located in glandular region. Swenson - Vibrating line 2mm in front. Ley - Located 1.31mm in front of anterior vibrating line. Distal end of bony palate or some what anterior to it. Chen- No fovea palatinae are anterior to vibrating line. present on or behind the anterior vibrating line.

37. Prosthetic considerations Position of fovea palatini vary considerably. So, clinician using this landmark as posterior extent of denture can deprive his patients from several millimeters of tissue coverage.

38. CLASSIFICATION OF HARD PALATE According to winkler - Based on the shape of palatal vault- U- shaped – most favorable for retention and lateral stability. V- shaped –less favorable for retention. FLAT –unfavorable. seen in resorbed ridges.

39. According to johnson et al, 1986 – Anteroposteriorly flat anterior curved posterior. mildly inclined anterior and curved posterior. steep anterior and posterior. Mesiodistally flat (1/4 inch deep from ridge) u- shaped (1/4-1/2inch deep) v- shaped (1/2 inch deep)

40. SOFT PALATE The soft palate is a muscular structure, encased in a mucous membrane, suspended between the oral pharynx and the nasal pharynx. Its sides are attached to the lateral pharyngeal walls. The anterior portion of the soft palate, near its junction with the hard palate, is almost immobile, whereas its posterior-most extent, the uvula, is capable of great excursion

41. Lateral to the uvula is the palatoglossal arch, containing the palatoglossal muscle, forming the anterior pillar of the oropharyngeal isthmus ( fauces ), extending into the side of the tongue.

42. Arising posteriorly is the palatopharyngeal arch, containing the palatopharyngeus muscle, forming the posterior pillar of the oropharyngeal isthmus extending into the lateral pharyngeal wall. The palatine tonsils are located between the two fauces in the tonsillar sinus

43. Prosthetic considerations The anatomy of soft palate determines the location of the distal border of maxillary denture base and posterior palatal seal The posterior extension of maxillary denture base lies in soft palate i.e. the palatine aponeurosis and overlying mucosa. This extension increases the denture bearing area and reduces the pressure on residual ridges and also improves the retention of the denture.

44. Palatine muscles and contour of soft palate determine the extent and contour of posterior palatal seal The seal should follow the contour of palatine bones and extend from hammular notch to hammular notch

45. PALATINE APONEUROSIS Thin and fibrous Forms fibrous base Supports the muscles andstrengthens the soft palate Attached to posterior border of hard palate behind palatine crest. Serves as insertion for tensor veli palatini and levator veli palatini , and origin for musculus uvula, palatoglossus and palatopharyngeus

46. Prosthetic considerations The posterior extent of the maxillary denture base rest in the muscular aponeurosis of soft palate . As this area is not susceptible to pressure atrophy and therefore allows moderate tissue displacement to maintain thin fluid film. This area is aponeurosis , it is strong & thick at the junction. The characteristics of aponeurosis , the overlying mucosa, activity of the palatal muscles & contour of the soft palate determines the extent & contour of the PPS.

47. PALATINE MUSCULATURE Levator veli palatini Tensor veli palatini Palatoglossus Palatopharyngeus Musculus uvulae

48. NAME ORIGIN INSERTION ACTION LEVATOR VELI PALATINI Petrous temporal, tymphanic temporal, auditory tube Palatal aponeurosis Elevates the soft palate TENSOR VELI PALATINI Scaphoid fossa , spine of sphenoid and auditory tube Palatal aponeurosis Tenses the soft palate MUSCULUS UVULAE Posterior nasal spine, palatine aponeurosis Uvula Elevates and retracts uvula PALATOGLOSSUS Fascia and muscles, lateral aspect of soft palate Side of the tongue Elevates root of the tongue, constricts fauces PALATOPHARYNGEUS Soft palate Thyroid cartilage and muscular wall of pharynx Constricts oropharyngeal isthmus and elevates larynx

49. TENSOR VELI PALATINI Thin triangular muscle Origin Scaphoid fossa of sphenoid bone at root of pterygoid plates Lateral side of auditory tube

50. Insertion Fibres winds over the pterygoid hammulus , passes through origin of buccinator and flattens to form palatine aponeurosis Actions Alone-pulls soft palate to one side With fellow-tightens soft palate anterior) Opens auditory tube

51. Prosthetic Considerations Stretches and depresses the anterior part of soft palate and there by closes the pharyngeal isthmus. This slender tendon when taut, could influence the denture contour in hamular notcharea

52. LEVATOR VELI PALATINI Cylindrical muscle Origin- Apex of petrous part of temporal bone, anterior to the opening of carotid canal Medial side of auditory tube.

53. Insertion Passes over upper margin of superior constrictor and enters pharynx and spreads in the soft palate between the palatopharyngeus Fibres inserted into upper surface of aponeurosis upto midline and blends with its fellow Actions Elevates soft palate Closes pharyngeal isthmus Opens auditory tube

54. Prosthetic Considerations Elevates soft palate and closes pharyngeal isthmus Closes the oral cavity from nasopharynx during swallowing as well as in determination of vibrating line.

55. PALATOGLOSSUS Small fasciculus that ends in palatoglossal arch Origin Aponeurosis of soft palate.

56. Insertion Continues at origin with fellow to side of tongue , fibres spread over lingual dorsum and some mingle with transverse linguae Actions Elevates root of tongue Approximates palatoglossal arch

57. Prosthetic Considerations Raises the tongue to close the oropharyngeal isthmus, this action brings lateral pressure to lingual extension of mandibular denture.

58. PALATOPHARYNGEUS Forms Palatopharyngeal arch 2 fasciculi separated by Levator palatini - anterior and posterior Origin Anterior fasciculus – posterior border of hard palate Posterior- palatine aponeurosis

59. The 2 unite at posterolateral border of soft palate Insertion Posterior border of thyroid cartilage of larynx Actions Pull pharynx up forward and medial and shorten it during swallowing Approximate palatopharyngeal arches

60. Prosthetic Considerations Arches the relaxed palate and depresses the tensed palate. Closes the pharyngeal isthmus by opposing the palatopharyngeal arches.

61. MUSCULUS UVULAE Origin – Arises from posterior nasal spine at the back of hard palate and from palatine aponeurosis . Insertion – Passes backwards and downwards to insert in to mucosa of uvula.

62. Actions – - Shortens tenses and rises the uvula. - Moves the uvula upwards and laterally and helps to complete the seal between the soft palate and pharynx in midline region when palate is elevated

63. PASSAVANTS RIDGE Few fibres of Palatopharyngeus pass circularly deep to mucous membrane of pharynx and form a sphincter internal to superior constrictor The passavant’s muscle on contraction raises the ridge on posterior wall of pharynx Soft palate when elevated comes in contact with this ridge and closes the pharyngeal isthmus .

64. CLASSIFICATION OF SOFT PALATE Class-I Soft palate is horizontal as it extends posteriorly with minimal muscular activity Considerable amount of mm separates the anterior and posterior vibrating line Will give a wide posterior palatal seal which is not deep

65. Class II Soft palate make a 45 degree angle with hard palate Tissue coverage is less for posterior palatal seal than class I

66. Class III Most acute contour about 70 degrees Requires marked elevation of musculature to create the velopharyngeal closure Seen with V shaped palatal vault

67. HOUSE CLASSIFICATION OF PALATAL THROAT FORMS found on a line drawn between the two hamular notches: Class I 5 - 12mm distal ( more than 5mm of movable tissue available for post- damming---ideal for retention).

68. Class II 3-5mm distal (1-5mm of movable tissue available for post damming. Good retention is usually possible.

69. Class III: 3-5mm anterior (less than 1mm of movable tissue available for post damming. Retention is usually poor

70. VASCULAR SUPPLY The vascular supply of the palate is derived chiefly from the greater and lesser palatine branches of the maxillary artery, the ascending palatine branch of the facial artery, and the ascending pharyngeal artery from the external carotid artery

71. The greater and lesser palatine arteries descend in the pterygopalatine canal to enter the palate via the greater and lesser palatine foramina, respectively. The greater palatine artery passes anteriorly on the lateral aspect of the hard palate to supply the palatal mucosa, gingiva , and glands, and then proceeds to anastomose with the nasopalatine artery in the incisive canal.

72. The lesser palatine artery vascularizes the soft palate and tonsil and then anastomoses with the ascending palatine branch of the facial artery. The lesser palatine bifurcates, and one branch travels along the surface of the levator veli palatini muscle to vascularize the soft palate. The other branch perforates the superior constrictor muscle to serve the auditory tube and the tonsil.

73. The ascending pharyngeal artery from the external carotid artery travels along the lateral external surface of the superior constrictor muscle, reaches the levator veli palatini muscle, and gives off a palatine branch to serve the tonsil, auditory tube, and soft palate.

74. VENOUS DRAINAGE The veins of the hard palate pass into the pterygoid venous plexus The veins of the soft palate into the pharyngeal venous plexus.

75. SENSORY NERVE SUPPLY The greater and lesser palatine branches of the maxillary division of the trigeminal nerve, which also carry sensory fibers from the facial nerve via the greater petrosal nerve.

76. The nasopalatine nerve of the posterosuperior nasal branch of the maxillary division of the trigeminal nerve and the tonsillar branches of the glossopharyngeal nerve.

77. MOTOR NERVE SUPPLY The motor innervations of the tensor veli palatine is derived from the mandibular branch of the trigeminal nerve (via the nerve to the medial pterygoid muscle and the otic ganglion). The rest of the muscles of the palate – the cranial part of the accessory nerve via the pharyngeal plexus.

78. Palate - Pathology Palatine torus- focal outgrowth of bone of unknown etiology. Palatine tori

79. Occurs as a single prtuberance along the mid palatal suture. Or may also present as bilateral bone growth. Mucosa overlying is very thin. Prosthetic considerations- as the mucosa is thin denture should be relieved as it can be easily traumatized. sometimes it is large that is results in difficulty in phonation and construction of prosthesis, then surical intervention required.

80. Candidiasis

81. CONCLUSION The palate, representing the roof of the oral cavity, is divided into the hard palate, comprising the anterior two thirds, and the soft palate, comprising the remaining posterior one third. The knowledge about different structures present in hard and soft palate and their surface relation will help in making a prosthesis that will be in harmonious with the oral tissues by relieving the sensitive zones and using the resistant areas for retention. Several developmental and acquired defects like cleft palate and clefts or oronasal fistulas arising can be treated with appropriate obturators that will help in restoring the normal functions. Conditions like diabetes and other immune compromised states mostly seen in old age could result in change of mucosal integrity leading to diseases like candidiasis . The knowledge about these conditions will help in preventing such situations or can be diagnosed earlier.

82. REFERENCES Barry K B Berkovitz , G R Holland, Bernard j Moxham . Oral Anatomy, Histology and Embryology. Fourth edition, Mosby Elsevier 2009. Antonio Nanci , Ten Cate's Oral Histology: Development, Structure, and Function. Seventh Edition, Mosby Elsevier 2008. Sheldon Winkler. Essentials of complete Denture Prosthodontics , 4 th ed. AITBS Publishers, India 2009 Zarb AZ, Bolender CL, Steven E Eckert, R F Jacob, A H Fenton, R M stern. Prosthodontic Treatment for Edentulous Patients: Complete dentures and implant supported prostheses. 12 th edition, Elsevier, New Delhi 2004. Heartwell CM, Rahn AO. Syllabus of complete dentures. 4 th ed. Philadelphia: Lea & Febiger ; 1986.

83. 6. Alexander L. Martone , Linden F. Edwards. Anatomy of the mouth and related structures: Part III. Functional anatomic considerations . J. Prosthet Dent 12: 2; 206-219, 1962. 7. Sidney I. Silverman. Dimensions and displacement patterns of the posterior palatal seal. J. Prosthet Dent 25: 5, 470-488, May 1971. 8. Jacobson TE, Krol AJ. A contemporary review of the factors involved in complete denture retention, stability, and support. Part I: retention. J Prosthet Dent . 1983 Jan;49(1):5-15. 9. Jacobson TE, Krol AJ. A contemporary review of the factors involved in complete denture retention, stability, and support. Part III: support. J Prosthet Dent . 1983 Mar;49(3):306-13 .

84. Thank You