Tongue and Its Implications in Prosthodontics .pptx

Tongue and Its Implications in Prosthodontics

1. DEVELOPMENT OF TONGUE & IT’S IMPORTANCE IN PROSTHODONTICS Presented by- Dr. SANJANA AGRAWAL M.D.S 1 ST Year RUNGTA COLLEGE OF DENTAL SCIENCES & RESEARCH Department of Prosthodontics and Crown & Bridge 1

2. SPECIFIC LEARNING OBJECTIVES Sr. No. Core area Domain Category 1 Introduction Development of Tongue Classification of Tongue External Surface of Tongue - Papillae of Tongue - Muscles of Tongue Cognitive Must Know 2 - Arterial Supply - Venous Drainage Lymphatic Drainage Nerve Supply Function of Tongue Tongue Anomalies - Prosthodontics Implications Cognitive Must Know 3 Conclusion Take home message Affective Must Know 2

3. CONTENT Introduction Development of Tongue Classification of Tongue External Surface of Tongue Papillae of Tongue Muscles of Tongue Arterial Supply Venous Drainage Lymphatic Drainage Nerve Supply Function of Tongue Tongue Anomalies Prosthodontics Implications Conclusion Take Home Message References 3

4. INTRODUCTION 4 Tongue is muscular organ which is anchored to hyoid bone, mandible, soft palate, pharyngeal wall and styloid process in the oral cavity. It is associated with numerous vital functioning. Lack of any activity may lead to severe impairment in socialization and patient’s quality of life. T ongue plays an important role in formation and production of effective speech.

5. DEVELOPMENT OF TONGUE

6. Right & left lingual swellings & tuberculum impar formed in relation to the first arch, and hypobranchial eminence formed in relation to the medial ends of the third & fourth arches. Immediately behind the tuberculum impar, the epithelium proliferates to form a down growth (thyroglossal duct) from which the thyroid gland develops.

7. Another, midline swelling is seen in relation to the medial ends of the second, third and fourth arches. This swelling is called the hypobranchial eminence or copula of His . The eminence soon shows a subdivision into a cranial part related to the second and third arches (called the copula ) and a caudal part related to the fourth arch . The caudal part forms the epiglottis.

8. Epithelium The anterior two thirds of the tongue is formed by fusion of the tuberculum impar and the two lingual swellings, thus derived from the mandibular arch . The posterior one-third of the tongue is formed from the cranial part of the hypobranchial eminence i.e third arch. Textbook of Human Embryology- Inderbir Singh 7th Edition

9. The second arch mesoderm gets buried below the surface. The third arch mesoderm grows over it to fuse with the mesoderm of the first arch . c) The posterior most part of the tongue is derived from the fourth arch.

10. Mucosa The mucosa of tongue is derived from endoderm of foregut . Muscles The muscles of the tongue is derived from the occipital myotomes and supplied by the hypoglossal nerve. Connective Tissue The stroma is derived from the pharyngeal arch mesoderm.

11. CLASSIFICATION OF TONGUE

12. FUNCTIONAL TONGUE CLASSIFICATION ACCORDING TO DEGREE OF ACTIVITY BY BARNETT KESSLER The Occupational tongue : Apply to those people whose activities require increased tongue action. E.g. jurists, teachers, lecturers, preachers, musicians. The Still tongue: Also called Passive tongue. Have limited tongue activity. Could be due to injury, deformity etc. E.g. ankyloglossia The Normal tongue: It is of prosthodontist’s delight. Tongue exhibit normal function and range of movements. The Habitual tongue : It refers to the disturbing powerful movements of the tongue developed due to habit. Base of the tongue is thick and powerful and imposes dislodging forces on the denture. International Journal of Applied Dental Sciences 2020; 6(2): 362-366

13. POSITION ACCORDING TO WRIGHT Class 1: Tongue lies on the floor of the mouth with the tip forwards and slightly below the incisal edges of the mandibular anterior teeth. Class II: Tongue is flattened and broadened but the tip is in normal position. Class III: Tongue is retracted and depressed into the floor of the mouth with the tip curled upwards, downwards or assimilated into the body of the tongue.

14. M.M House (1958) Class 1: Normal in size, development and function. Sufficient teeth are present to maintain normal form and function. Class 2: Teeth have been absent long enough to permit a change in the form and function of the tongue. Class 3: Excessively large tongue. All teeth have been absent for an extended period of time, allowing for abnormal development of the size of tongue.

15. EXTERNAL FEATURES OF TONGUE

16. The tongue has: 1. A root, 2. A tip, and 3. A body, (a) a curved superior surface or dorsum , (b) an inferior surface or ventral . The dorsum is divided into oral and pharyngeal parts. B D Chaurasia’s Human Anatomy Volume 3, Sixth edition

17. The dorsum of the tongue is convex in all directions. It is divided into: (a) An oral part or anterior two-thirds , and (b) a pharyngeal part or posterior one-third , (c) a small posterior most part

18. The two parts are divided by a faint V- shaped groove, Sulcus terminalis . The two limbs of the 'V meet at a median pit, named Foramen caecum .

19. The inferior surface is covered with a smooth mucous membrane, which shows a median fold called the frenulum linguae . On either side of the frenulum there is a prominence produced by the deep lingual veins. More laterally there is a fold called the plica fimbriata that is directed forwards and medially towards the tip of the tongue.

20. The posteriormost part of the tongue is connected to the epiglottis by three folds of mucous membrane. These are the median glossoepiglottic fold and the right and left lateral glossoepiglottic folds. On either side of the median fold there is a depression called the vallecula . The lateral folds separate the vallecula from the piriform fossa .

21. PAPILLAE OF TONGUE

22. These are projections of mucous membrane which give the anterior two-thirds of the tongue its characteristic roughness. B D Chaurasia’s Human Anatomy Volume 3, Sixth edition

23. Vallate or Circumvallate Papillae. They are large in size 1-2 mm in diameter and are 8-12 in number. They are situated immediately in front of the sulcus terminalis. Each papilla is a cylindrical projection surrounded by a circular sulcus. The walls of the papilla have taste buds .

24. Fungiform Papillae They are numerous near the tip and margins of the tongue. These are smaller than the vallate papillae but larger than the filiform papillae. Each papilla consists of a narrow pedicle and a large rounded head. They are distinguished by their bright red colour .

25. Filiform Papillae or Conical Papillae Cover the presulcal area of the dorsum of the tongue, and give a velvety appearance. They are the smallest and most numerous of the lingual papillae. Each is pointed and covered with keratin .

26. Foliate Papillae They are present at the lateral border just in front of circumvallate papillae. They are leaf shaped.

27. MUSCLES OF TONGUE

28. A middle fibrous septum divides the tongue into right and left halves. Each half contains four intrinsic and four extrinsic muscles. B D Chaurasia’s Human Anatomy Volume 3, Sixth edition

29. INTRINSIC MUSCLES The intrinsic muscles occupy the upper part of the tongue, and are attached to the submucous fibrous layer and to the median fibrous septum. They alter the shape of the tongue .

30. SUPERIOR LONGITUDINAL Arises from the fibrous tissue deep to mucous membrane on dorsum of tongue. This muscle acts to elevate the tip and sides of the tongue superiorly . This shapes the tongue dorsum into a concavity.

31. INFERIOR LONGITUDINAL It originates from the fibrous tissue beneath the mucous membrane stretching from tip of tongue longitudinally back to the root of the tongue and hyoid bone. The inferior longitudinal muscle acts to curl the tip of the tongue inferiorly. This makes dorsum of tongue Convex

32. TRANSVERSE Lies as a sheet on either side of midline in a plane which is deep to superior longitudinal muscle. Contraction of this muscle acts to narrow and increase the depth of the tongue.

33. VERTICAL Found at borders of anterior part of the tongue and makes the tongue broad and flattened.

34. EXTRINSIC MUSCLES They connect the tongue to other structures i.e. 1. To mandible via Genioglossus 2. To hyoid bone via Hyoglossus 3. To styloid process via Styloglossus 4. To palate via Palatoglossus

35. PALATOGLOSSUS MUSCLE Origin: Oral surface of palatine aponeurosis Insertion: Descends in the palatoglossal arch to the side of tongue at the junction of oral and pharyngeal parts. Actions: Pulls up the root of tongue i.e. it elevates the tongue, approximates the palatoglossal arches and thus closes the oropharyngeal isthmus.

36. HYOGLOSSUS MUSCLE Origin: Whole length of greater cornua and lateral part of hyoid bone. Insertion: Side of tongue between styloglossus and inferior longitudinal muscle of tongue. Actions: Depresses tongue , makes dorsum convex , retracts the protruded tongue.

37. STYLOGLOSSUS MUSCLE Origin: Tip and part of anterior surface of styloid process Insertion : Into the side of tongue Actions: Pulls tongue upwards and backwards i.e. retracts the tongue. Styloglossus

38. GENIOGLOSSUS MUSCLE Origin: Upper genial tubercle of mandible Insertion: Upper fibers into the tip of tongue Middle fibers into the dorsum Lower fibers into the hyoid bone Actions : Retracts the tongue Depresses the tongue Pulls the posterior part of tongue forwards and protrudes the tongue. It is a life saving muscle .

39. Intrinsic Muscles Actions Superior Longitudinal Shortens the tongue makes its dorsum concave Inferior Longitudinal Shortens the tongue makes its dorsum convex Transverse Tongue narrow and elongated Vertical Tongue broad and flattened Extrinsic Muscles Actions Genioglossus Protrudes the tongue Hypoglossus Depresses the tongue Styloglossus Retracts the tongue Palatoglossus Elevates the tongue

40. ARTERIAL SUPPLY OF TONGUE

41. It is chiefly derived from the lingual artery , a branch of the external carotid artery. The root of the tongue is also supplied by the tonsillar artery , a branch of facial artery and ascending pharyngeal branch of external carotid artery. B D Chaurasia’s Human Anatomy Volume 3, Sixth edition

42. VENOUS DRAINAGE OF TONGUE

43. The deep lingual vein is the largest and principal vein of the tongue. It runs backwards and crosses the genioglossus and the hyoglossus below the hypoglossal nerve. These veins unite at the posterior border of the hyoglossus to form the lingual vein which ends either in the common facial vein or in the internal jugular vein. B D Chaurasia’s Human Anatomy Volume 3, Sixth edition

44. LYMPHATIC DRAINAGE OF TONGUE

45. The tip of the tongue drains bilaterally to the submental nodes . The right and left halves of the remaining part of the anterior two-thirds of the tongue drain unilaterally to the submandibular nodes . B D Chaurasia’s Human Anatomy Volume 3, Sixth edition

46. The posterior-most part and posterior one third of tongue drains bilaterally into upper deep cervical lymph nodes including jugulodigastric nodes. The whole lymph finally drains into jugulo-omohyoid nodes . These are known as lymph nodes of tongue.

47. NERVE SUPPLY OF TONGUE

48. MOTOR NERVES All the Intrinsic and Extrinsic muscles, except the palatoglossus, are supplied by the hypoglossal nerve . The palatoglossus is supplied by the cranial root of the accessory nerve through the pharyngeal plexus . B D Chaurasia’s Human Anatomy Volume 3, Sixth edition

49. SENSORY NERVES The lingual nerve is the nerve of general sensation and the chorda tympani is the nerve of taste for the anterior two-thirds of the tongue except vallate papillae. The glossopharyngeal nerve is the nerve for both general sensation and taste for the posterior one-third of the tongue including the circumvallate papillae. The posteriormost part of the tongue is supplied by the vagus nerve through the internal laryngeal branch .

50. TASTE BUDS OF TONGUE

51. Taste buds are numerous on the sides of the circumvallate papillae and on the walls of surrounding sulci. Taste buds are numerous over the foliate papillae and over the posterior one-third of the tongue. They are sparsely distributed on the fungiform papillae, soft palate , epiglottis and the pharynx. No taste buds are present on the mid dorsal region of oral part of the tongue.

52. FUNCTIONS OF TONGUE

53. MASTICATION Mastication is defined as the reduction of food in size, changing in consistency, mixing it with saliva and forming into a bolus suitable for swallowing.

54. This break down action is highly organized complex of neuromuscular and digestive activities that integrate various components of masticatory system such as teeth, muscles, TMJ, lips, cheeks, tongue, palate and salivary secretions. Besides controlling, with the assistance of the buccinator the position of the food between the teeth, it also turns the food and mixes it with saliva. On the other hand, it has been evident that the tongue significantly influences masticatory efficiency. The tongue movement with the mouth closed appears to be closer to movement during mastication than movement with the mouth open.

55. SWALLOWING OR DEGLUTITION Deglutition is the act or process of swallowing. Both suckling and swallowing movements start developing from 32 nd week of I.U. life. 2 types of swallow pattern – a) Infantile Swallow b) Mature Swallow

56. RESPIRATION Even though nose forms the primary portal of entry for respiration, the mandible and the tongue posture are the major determinants. Mouth and nose forms the anatomic beginning of the respiratory system but the patency of the airway in the nose and oral cavity is maintained by the bony skeleton and adaptive posture of the tongue. A B

57. SPEECH Tongue helps in the formation of sounds like – s, z, t, d, sh , e, g, is. Development of speech takes place during the first year of life. It also follows the anterior to the posterior pattern of maturation like the swallowing pattern .

58. ANOMALIES OF TONGUE

59. MICROGLOSSIA It is the presence of small rudimentary tongue. The protruded tongue tip reaches the lower incisors at rest and the floor of the mouth is elevated. The dental arch reflects the small tongue size with extreme crowding in the premolar area. Shafer’s Textbook of Oral Pathology, Eighth Edition

60. Management Thick lingual flange is to be made in the mandibular denture to obtain the lingual seal, along with placement of wider posterior teeth.

61. MACROGLOSSIA Crenation or scalloping of the lateral borders of the tongue. T ips of scalloping fit into the interproximal spaces between the teeth occurs. In edentulous patient tongue appear as elevated and spread out laterally causing difficulty in wearing a denture. Shafer’s Textbook of Oral Pathology, Eighth Edition

62. Management Proper designing of the lingual flange at the wax up stage helps to increase the stability of mandibular denture. This can be achieved by adding very little wax, behind the incisors region while behind the premolars, a flat or slightly concave surface should be established. In the molar and retromolar region, the polished surface is designed to be slightly concave. Narrow posterior teeth should be selected.

63. ANKYLOGLOSSIA / TONGUE TIE Ankyloglossia or tongue tie may hinder free tongue movements and may result in distortion and substitution of tongue tip sounds ( linguoalveolar ). The sounds affected are (l, t, d, n, s) and (z) because of restricted elevation of tongue tip. Shafer’s Textbook of Oral Pathology, Eighth Edition

64. Management Surgical excision of the tongue tie is to be done. The lower denture is to be fabricated before the surgical phase. Following the surgery, the lower denture acts as a barrier to prevent possibility of any reattachment of the frenum .

65. FISSURED TONGUE Well marked fissures increases with age, as does the number, width and depth of the fissures in affected individuals. It is manifested as small furrows or grooves on the dorsal surface. It is usually painless . Management No definitive therapy or medication is required . If symptomatic, patients advice to brush the dorsum of the tongue to eliminate debris that may serve as an irritant. Shafer’s Textbook of Oral Pathology, Eighth Edition

66. MEDIAN RHOMBOID GLOSSITIS It is a developmental defect resulting from an incomplete decsent of tuberculum impar and entrapment of a portion between fusing lateral halves of the tongue. It appears as an ovoid, diamond or rhomboidal shaped reddish patch or plaque. The surface is dusky red and completely devoid of filiform papillae and usually smooth. Management No treatment T hose with symptoms (pain or burning sensation)- an antifungal medication Shafer’s Textbook of Oral Pathology, Eighth Edition

67. BENINGN MIGRATORY GLOSSITIS It refers to irregularly shaped reddish areas of depapillation . It is asymptomatic, but the patient may complain of burning sensation. Initially appears as a small erythematous, non- indurated, atrophic lesion, bordered by a slightly elevated distinct rim that varies from gray white to light yellow. Management No treatment Symptomatic lesion treated with Topical prednisolone, Systemic antifungal drugs. Shafer’s Textbook of Oral Pathology, Eighth Edition

68. HAIRY TONGUE It designates an overgrowth of the filiform papillae on the dorsum of the tongue. The lesion involves the dorsum, particularly the middle and posterior one-third. There is hypertrophy of filiform papillae. The papillae may reach a length of 2 cm. Management Proper oral hygiene Laser - carbon dioxide laser Electrodessication – for surgical removal of filiform papillae . Shafer’s Textbook of Oral Pathology, Eighth Edition

69. PROSTHODONTIC IMPLICATIONS OF TONGUE

70. TRAY SELECTION While seating the mandibular tray in position, the patient is asked to lift the tongue and bring it forward to avoid entrapping it below the tray. The lingual borders of the tray are checked by functional movements of the tongue by bring the tongue straight out. International Journal of Applied Dental Sciences 2020; 6(2): 362-366

71. If the tray rises vigorously from the posterior end, the distolingual flange could be overextended, thus has to be reduced. Displacement of the tray when the tongue is moved to the right side would mean that the left side (mylohyoid portion) is overextended and vice versa. Displacement of the tray when the tongue is raised toward the soft palate could mean that the anterior portion or lingual frenum is overextended.

72. BORDER MOLDING Lingual frenum and sublingual flange- (premolar to premolar). The patient is instructed to wipe his lower lip from side to side with the tongue tip and then asked to protrude the tongue to determines the height of the anterior lingual flange and records the frenum. Then the patient is asked to push his tongue forcefully against the front the front part of the palate to develop the thickness of the flange. International Journal of Applied Dental Sciences 2020; 6(2): 362-366

73. Mylohyoid portion To mould the right lingual flange the patient is instructed to bring the tongue in contact with the left cheek and vice versa. This determines the length of the flange in this region. The flange in this region must slope towards the tongue to allow for the action of the mylohyoid.

74. Retro mylohyoid portion Distal most part of the lingual flange which rises up towards the retromolar pad is limited by the retro mylohyoid curtain. The patient is asked to wide open the mouth, protrude the tongue and then close the jaw against resistance from the operators thumb.

75. OCCLUSAL PLANE The occlusal plane must lie at the lateral border of the tongue, if higher may result in unstable denture due to lateral tilting forces directed against the teeth. International Journal of Applied Dental Sciences 2020; 6(2): 362-366

76. JAW RELATION The mandibular wax rim and consequently the occlusal plane is at 2/3rd the height of the retromolar pad. The occlusal plane must lie at the lateral border of the tongue. While recording vertical relation the tongue must be in its normal position. While training the patient to close in centric, the patient may be asked to touch his tongue to the palate and swallow. International Journal of Applied Dental Sciences 2020; 6(2): 362-366

77. TEETH ARRANGEMENT The mylohyoid ridge is a reliable guide. The lingual cusps of the molars are aligned in harmony with the mylohyoid ridge, never lingual to it. Placing them far too lingually can cause: cramping of the tongue, tongue biting and instability of the denture during tongue function. International Journal of Applied Dental Sciences 2020; 6(2): 362-366

78. Also, in order to balance the forces of the tongue pressing outwards with the forces of the cheeks and lips pressing inward, neutral zone technique was employed. Failure to recognize the importance of ideal tooth position, flange form and contour often results in dentures which are unstable and unsatisfactory while those in harmony with neuromuscular function are successful and stable dentures.

79. SPEECH CONSIDERATIONS: SOUNDS AFFECTED BY THE TONGUE Linguo-dental They are produced by the contacting the tip of the tongue against palatal surface of the upper anterior teeth. Eg:Th Linguopalatal They are produced by the tongue and palate. Eg : D,N,L,T. International Journal of Applied Dental Sciences 2020; 6(2): 362-366

80. Alveolar sounds They are produced by the tongue placed against anterior portion of hard palate (D,T). Nasal (N, NG) Excessive denture base thickness in palatal surface causes loss of tongue room and decreased volume of air. Expression of linguopalatal and linguoalveolar sounds may be difficult. If the teeth are placed far too lingually, or the arch is too narrow the tongue will be cramped resulting in faulty phonation, affecting linguoalveolar and lateral lingual sounds.

81. POLISHED SURFACE CONTOUR Martonet emphasized that the stability of lower denture depends upon the position of the tongue as it was considered to be a more powerful muscle than the lips and cheeks. It exerts a force of 16.4 Psi, while the lips and cheeks exerts only 4.3 Psi. Therefore, when molding of the external contours was considered, the lingual surface was the surface choice. C are must be taken while contouring the lingual surface as its influence can mitigate against stability. International Journal of Applied Dental Sciences 2020; 6(2): 362-366

82. FOOD TROUGH FORMATION AND MASTICATION The opening and closing movements of the mandible during mastication is initiated by the neuromuscular movement of the tongue. While mastication, some of the food may escape out from the premolar region and may falls into the buccal or lingual space which is then retrieved by the buccinator and the tongue, respectively. The fixation of the modiolus on the buccal surface of the lower first premolar initiates the posterior movement of food by the cheek along the tongue further facilitating deglutition. International Journal of Applied Dental Sciences 2020; 6(2): 362-366

83. International Journal of Applied Dental Sciences 2020; 6(2): 362-366

84. Tongue is an important organ which contributes to speech, mastication, deglutition and taste. The examination of the tongue plays a major role during the oral examination of the soft tissues. Tongue is an important factor to be considered for proper prosthodontic treatment planning. CONCLUSION

85. Tongue plays a significant role in stability and retention of the complete denture. Its nature as such in prosthodontics has been important due to its anatomy and action on the lower dentures. So for fabrication of complete denture, the anatomy and physiologic characteristics of the tongue must be evaluated thoroughly. TAKE HOME MESSAGE

86. REFERENCES B D Chaurasia’s Human Anatomy Volume 3, Sixth edition Textbook of Human Embryology- Inderbir Singh 7th Edition Orban’s Oral Histology and Embryology, Fourteenth Edition Shafer’s Textbook of Oral Pathology, Eighth Edition Boucher’s Prosthodontic Treatment for Edentulous patients, Ninth Edition Zarb Bolender Prosthodontic Treatment for Edentulous patients, Twelfth Edition Puri D, Dhawan P, Tandan P. T ongue and its prosthodontic implications. Int J Appl Dent Sci 2020;6(2):362-366.

87. Q n A L ateral throat form / retromylohyoid fossa/ eminence/ distolingual vestibule: The posterior region of the alveolo-lingual sulcus . Class I- Deep Class II- Moderate Class III- Shallow 2. Retromolar pad- a triangular pad of tissue at the distal end of the ridge. Its mucosa is composed of thin, nonkeratinized epithelium and submucosa contains loose areolar tissue, some glandular tissue, fires of the buccinator (buccally) , superior constrictor (lingually) , pterygomandibular raphae ( supero -posteriorly) and tendon of the temporalis.

88. 3. Centric Relation: A maxillomandibular relationship, independent of tooth contact, in which the condyles articulate in the anterior-superior position against the posterior slopes of the articular eminences; in this position, the mandible is restricted to a purely rotary movement; from this unstrained, physiologic, maxillomandibular relationship, the patient can make vertical, lateral or protrusive movements; it is a clinically useful, repeatable reference position. 4. Syndrome associated with Hairy tongue- is a condition triggered by the Epstein-Barr virus (EBV) and AIDS is associated with it.

89. 5. Palpation of Lymph Nodes- S ubmental lymph nodes : Use the fingers to palpate  just under the chin. Submandibular lymph nodes : Palpate by rolling the tissues  under the chin up and over the inferior border of the mandible . Deep cervical lymph nodes: Gently bend the patient's head forward and roll your fingers over the deeper muscles along the carotid arteries . 6. Functional Movements of patients in neutral zone- Swallowing Pursuing of lips Coughing Blowing Sucking

90. 5. Lines drawn in master cast during teeth arrangement-