1. Introduction and Review of Masticatory System

2. From DOCC 381 Concept Instruments and technique
Morphology of occlusion
Anatomy of mastication system
Mandibular movement
Neurophysiology of mastication
Sign and symptom of TMD
Occlusal splint

3. Introduction to DOCC 582 Aetiology and Epidermiology of TMD
Clinical assessment of masticatory system
Diagnosis and Classification of TMD
Oral parafunction
Trauma from occlusion
Management of TMD problem
Interocclusal appliances

4. Occlusion also Includes
Biological evolution
Development
Histology
Anatomy
Biomechanics
Physiology (Neurophysiology)
Adaptation
Pathology
Behaviour sciences
Clinical diagnosis
Therapy

5. Definition (Jablonski, 1982)
The relationship between all the components of the masticatory system in normal function, dysfunction, and parafunction, including the morphological and functional features of contacting surfaces of opposing teeth and restorations, occlusal trauma and dysfunction, neuromuscular physiology, the TMJ and muscle function, swallowing and mastication, psychological status, and the diagnosis, prevention, and treatment of functional disorders of the masticatory system
The relationship between all the components of the masticatory system in normal function, dysfunction, and parafunction, including the morphological and functional features of contacting surfaces of opposing teeth and restorations, occlusal trauma and dysfunction, neuromuscular physiology, the TMJ and muscle function, swallowing and mastication, psychological status, and the diagnosis, prevention, and treatment of functional disorders of the masticatory system
The relationship between all the components of the masticatory system in normal function, dysfunction, and parafunction, including the morphological and functional features of contacting surfaces of opposing teeth and restorations, occlusal trauma and dysfunction, neuromuscular physiology, the TMJ and muscle function, swallowing and mastication, psychological status, and the diagnosis, prevention, and treatment of functional disorders of the masticatory system
The relationship between all the components of the masticatory system in normal function, dysfunction, and parafunction, including the morphological and functional features of contacting surfaces of opposing teeth and restorations, occlusal trauma and dysfunction, neuromuscular physiology, the TMJ and muscle function, swallowing and mastication, psychological status, and the diagnosis, prevention, and treatment of functional disorders of the masticatory system
The relationship between all the components of the masticatory system in normal function, dysfunction, and parafunction, including the morphological and functional features of contacting surfaces of opposing teeth and restorations, occlusal trauma and dysfunction, neuromuscular physiology, the TMJ and muscle function, swallowing and mastication, psychological status, and the diagnosis, prevention, and treatment of functional disorders of the masticatory system
The relationship between all the components of the masticatory system in normal function, dysfunction, and parafunction, including the morphological and functional features of contacting surfaces of opposing teeth and restorations, occlusal trauma and dysfunction, neuromuscular physiology, the TMJ and muscle function, swallowing and mastication, psychological status, and the diagnosis, prevention, and treatment of functional disorders of the masticatory system
The relationship between all the components of the masticatory system in normal function, dysfunction, and parafunction, including the morphological and functional features of contacting surfaces of opposing teeth and restorations, occlusal trauma and dysfunction, neuromuscular physiology, the TMJ and muscle function, swallowing and mastication, psychological status, and the diagnosis, prevention, and treatment of functional disorders of the masticatory system
The relationship between all the components of the masticatory system in normal function, dysfunction, and parafunction, including the morphological and functional features of contacting surfaces of opposing teeth and restorations, occlusal trauma and dysfunction, neuromuscular physiology, the TMJ and muscle function, swallowing and mastication, psychological status, and the diagnosis, prevention, and treatment of functional disorders of the masticatory system
The relationship between all the components of the masticatory system in normal function, dysfunction, and parafunction, including the morphological and functional features of contacting surfaces of opposing teeth and restorations, occlusal trauma and dysfunction, neuromuscular physiology, the TMJ and muscle function, swallowing and mastication, psychological status, and the diagnosis, prevention, and treatment of functional disorders of the masticatory system
The relationship between all the components of the masticatory system in normal function, dysfunction, and parafunction, including the morphological and functional features of contacting surfaces of opposing teeth and restorations, occlusal trauma and dysfunction, neuromuscular physiology, the TMJ and muscle function, swallowing and mastication, psychological status, and the diagnosis, prevention, and treatment of functional disorders of the masticatory system

6. Objectives and Goals
The subject of occlusion serves as a natural interface between certain of the biologic and behavioural sciences and the clinical sciences.
The subject of occlusion is, in the view of many, the medium that brings all branches of dentistry together (Ricketts, 1969)

7. The Masticatory System
A dynamic biomechanical musculoskeletal system

8. Components of the Mastication
Dentitions
Periodontal supporting tissues
Maxilla and Mandible
Temporomandibular Joint
Mandibular musculature
Muscles of lips, cheeks, and tongue
Involving soft tissue
Supplying innervation and vasculation

9. Primary Dentition Maxillary teeth Mandibular teeth Months 8 10 13 1619 27 29 1 2 4 3 5
Mandibular teeth
Months

10. Permanent Dentition Maxillary teeth Mandibular teeth Years 6 8 10 2 43 5 12 20 7 1
Maxillary teeth
Mandibular teeth
Years

11. Loss of Teeth Causes Occlusal Disharmony
Early loss of deciduous teeth without space retaining appliances
Loss of mandibular first molar
lingual and mesial tipping of mandibular 2nd and 3rd molar
Loss vertical dimension
Changing in masticatory habit and muscle tonicity

12. Periodontal Supporting Tissues
Cementum
Periodontal ligament
Supporting bone
Usually, periodontium is protected against injury by neuromuscular reflexes

13. Problems to Periodontium
Periodontal trauma
pattern of mastication
Loss of teeth
loss of periodontal support
Faulty restoration
Abnormal occlusal force; bruxism, clenching

14. Temporomandibular Joint (TMJ)
A complex giniglymoarthrodial (hinge and glide) articulation with limited capability of
diarthrosis (free movement)

15. Histology of TMJ Area

16. Temporomandibular Joint (TMJ)
Composed of
Condyle
Mandibular fossa
Articular capsule
Synovial tissue
Articular disc
Ligaments

17. Mandibular Condyle Modified barrel shape approx. 20 x 10 mm (ML x AP)
Perpendicular to the ascending ramus of mandible
Dense cortical bone covered with dense fibrous connective tissue with irregular cartilage like cell

18. Mandibular Fossa Dense cortical bony surface of temporal bone
Posterior to articular eminence
Posterior nonarticular fossa is formed by tempanic plate
Thin at the roof of the fossa and tympanic plate

19. Articular Capsule and Disk

20. Articular Capsule Ligamentous capsule surrounds the joint
Attached to the neck of the condyle and around the border of the articular surface of the temporal bone
anterolateral aspect of the capsule may thicken form the Temporomandibular ligament function as stabilising structure

21. Articular Capsule Consist of
internal synovial layer
outer fibrous layer containing veins, nerves, and collagen fibres.
Innervation of capsule disk arises from CN V; auriculotemporal and masseteric nerves
Venous plexus at posterior aspect

22. Synovial tissue
Synovial cell and connective tissue covering the lower and upper-joint spaces
Synovial fluid, a proteoglycan-hyaluronic acid complex acts as a lubricant and may participated in nutritional and metabolic interchange for central part.

23. Articular Disk (Meniscus)
Biconcave oval structure interposed between the condyle and the temporal bone
1 mm in the middle and 2-3 mm at periphery
Dense collagenous connective tissue
Centre area is a vascular, hyaine and devoid of nerve

24. Articular Disk (Meniscus)
Fuse to a strong ligament at lateral side connect to the neck of the condyle
The other borders are attached to capsule ligaments or synovial membranes separate between two joint spaces.

25. TMJ Ligaments

26. Temporomandibular ligament
Ligaments
Temporomandibular ligament
extend from base of zygomatic process of the temporal bone downward and oblique to the neck of the condyle

27. Stylomandibular ligament
Ligaments
Stylomandibular ligament
From styloid process and runs downward and forward to attach broadly on the inner aspect of the angle of mandible

28. Sphenomandibular ligament
Ligaments
Sphenomandibular ligament
arising from the angular spine of sphenoid bone and petrotympanic fissure, ending at lingula of mandible

29. Functions of Ligaments
Accessory ligaments may limit border movements of the mandible
Fibrous capsule and TM ligament may limit of extreme lateral movements in wide opening of mandible

30. Masticatory Muscles
Masseter muscle
Temporalis muscle
Medial pterygoid muscle
Lateral pterygoid muscle

31. Masster muscle Superficial layer
O : lower border of malar bone, Zygomatic arch & zygomatic process of maxilla
R : Downward and Backward
I : Angle of mandible and inferior half of the lateral side of mandible

32. Masster muscle Deep layer O : Internal surface of zygomatic arch
R : Downward (vertical)
I : Ramus of mandible and base of coronoid process
50 degree between 2 layers

33. Temporalis muscle 3 bundles Anterior bundle (vertical fibre)
Action: Mandible elevator (Close jaws), crushing and chewing at C.O.
Inaction: Mandible depression (except Max. Opening and Opening against resistance)

34. Temporalis muscle Posterior bundle (Horizontal bundle)
Action: Mand. retraction and positioner
Inaction: Mand. depression and protrusion
Intermediate bundle
Action: Protrisive movement
Nerve supply
Ant. and Post. deep temporal nerve

35. Med. Pterygoid muscle
Rectangular shape at medial surface of ramus, synergistic with masseter muscle
O : Pterygoid fossa and medial surf. of the lateral pterygoid plate
I : Inf. + Post. border of ramus and angle of mand.
R : Downward and Backward
N : Medial Pterygoid nerve

36. Lat. Pterygoid muscle Superior head Inferior head
O: Wing of sphenoid and infratemporal crest
R: Downward and Backward
Inferior head
O: Lateral surf. of lateral pterygoid plate
R: Upward and backward

37. Lat. Pterygoid muscle Insertion of superior and inferior heads
Ant. portion of the condylar neck (pterygoid fovea)
Ant. surface of the articular capsule
Ant. Border of the disk
Function
Open the jaws, protrude and lateral movement with moving disk forward

38. Lat. Pterygoid muscle Superior head Inferior head Nerve supply
Synergistic with elevator group of muscle for closing and clenching
Inferior head
Synergistic with suprahyoid group of muscle for opening jaw
Nerve supply
Lateral pterygoid nerve

39. Non Masticatory Muscle
Digastric muscle
Mylohyoid muscle
Geniohyoid muscle
Orbicularis Oris

40. Non Masticatory Muscle

41. Types of Mandibular Movement
Rotational movement
Horizontal axis of rotation
Frontal (vertical) axis of rotation
Sagittal axis of rotation
Translational movement

42. Rotational Movement
Around the horizontal axis (hinge axis)

43. Rotational Movement
Around the frontal (vertical) axis

44. Rotational Movement
Around the sagittal axis

45. Translational movement

46. Sagittal Plane Border Movement

47. Sagittal Plane Border Movement
Posterior open border
Anterior open border
Superior contact border
Functional movements

48. Horizontal Plane Border Movement
Left lateral border
Continued left lateral border
with protrusion
Right lateral border
Continued right lateral border
Functional movements

49. Horizontal Plane Border Movement
Continued right lateral border with protrusion

50. Horizontal Plane Border Movement
Functional movements

51. Frontal (Vertical) Border and Functional Movement

52. Frontal (Vertical) Border and Functional Movement
Left lateral superior border

53. Frontal (Vertical) Border and Functional Movement
Right lateral opening border

54. Frontal (Vertical) Border and Functional Movement
Functional movements

55. References
Ash and Ramfjord. Occlusion 4th edition. W.B. Saunders Company, 1995
Mohl, Zarb, Carlsson and Rugh. A textbook of Occlusion. Quintessence Publishing Co., 1998
Sicher and DuBrul. Oral Anatomy 6th edition. The C.V. Mosby company, 1975
Kraus, Jordan and Abrams. Dental anatomy and Occlusion. The Williams and Wilkins company, 1969

56. Thank you