Occlusion - Midterm

  1. Occlusion is
    the static relationship of the teeth and is basic to all aspects of dentistry. The act of being closed, maxillary teeth contact mandibular teeth.
  2. Intra-arch Alignment - Plane of Occlusion
    • Maxilla - Convex
    • Mandible - Concave; Curve Of Wilson and Bonwill’s Triangle (Frontal); Curve Of Spee (Sagittal); Monson Sphere (4" radius)
  3. Intra-arch Alignment - Tooth Angulation
    • Mandible - Sagittal: Anterior and posterior teeth inclined mesially
    • Maxilla - Sagittal: Anterior teeth inclined mesially; 3rd molar inclined distally
    • Mandible - Frontal: Posterior teeth inclined lingually
    • Maxilla - Frontal: Posterior teeth inclined buccally
  4. Inter-Arch Alignment
  5. Occlusal Table
    Area between the buccal and lingual cusp tips; 50 - 60% of total buccolingual dimension
  6. Arch length
    • Distance from distal of last molar to distal surface of opposite last molar
    • Maxillary arch (128mm) slightly larger than mandibular (126mm) due to width of mandibular incisors
  7. Arch Width
    • Distance across the arch
    • Mandibular width less than maxillary arch; Maxillary tooth facial to mandibular tooth
    • Mandibular BOL with Maxillary CFL
    • Maxillary LOL with Mandibular CFL
  8. During chewing, Maxillary buccal cusp prevent _____. Mandibular lingual cusps prevent _____. Cheek, lip and tongue _________.
    • cheek biting
    • tongue biting
    • replace food onto occlusal surface
  9. Supporting Cusps
    • Contact central fossa
    • maxillary lingual & mandibular buccal cusps
  10. Guiding/Non Supporting Cusps
    • Minimize tissue trauma
    • maintain food on occlusal table
    • guide the mandible during movements
  11. Functional outer inclines/aspects
    small area (1mm) on supporting cusp, only area of outer incline with functional significance
    Mandibular lingual contact maxillary central fossa. Maxillary buccal contact mandibular central fossa.
  13. Class I Molar Occlusion (80%)
    Mesiobuccal cusp of mandibular first molar occludes _________;
    Max ML cusp of M1 occludes ________;
    Mesiobuccal cusp of the maxillary first molar _______.
    • in the embrasure area between maxillary second premolar and first molar
    • in CF of Man M1
    • is aligned directly over the buccal groove of the mandibular first molar
  14. Class II Molar Occlusion
    Mandibular first molar more _____.
    Mesiobuccal cusp of mandibular first molar occludes ____________.
    Distolingual cusp of the maxillary first molar occludes ____________ and is aligned _________.
    • distal
    • in the central fossa area of the maxillary first molar
    • in the central fossa area of the mandibular first molar
    • directly under the buccal groove of the maxillary first molar
  15. Class III Molar Occlusion
    Mandibular first molar more _______.
    The distobuccal cusp of the mandibular first molar occludes _________.
    The mesiobuccal cusp of the maxillary first molar _________.
    The mesiolingual cusp of the maxillary first molar occludes ________.
    • mesial
    • in the embrasure between the maxillary second premolar and first molar
    • is situated over the embrasure between the mandibular first and second molar
    • in the mesial pit of the mandibular second molar
  16. The occlusion of anterior teeth functions
    • Incise food
    • Speech
    • Lip support
    • Esthetics
  17. The occlusion of posterior teeth functions
    • Break up food
    • Withstand occlusal forces
  18. Anterior Teeth angulation
    12-28 degree labial inclination of max. and mand. anterior teeth
  19. Anterior overlap
    • 3 to 5 mm of the mand. anterior teeth are hidden by the max.
    • Vertical overlap is the distance between the incisal edges
    • Horizontal overlap is the distance between the labial surfaces
  20. Vertical overlap+Horizontal overlap =
    Incisal Guidance
  21. 6 variations of anterior overbite
    • Class I: Normal overbite
    • Class II Div 1: Deep overbite (Man. occlude w/ the gingival third of Max) & Normal labial inclination
    • Class II Div 2: Deep overbite & lingual inclination of max. incisors
    • Class III: Edge to Edge anterior relationship
    • Class III: with reverse anterior relationship
    • Anterior open bite: no incisal guidance when post teeth occlude
  22. Morphology of condyles of mandible
    • The medial pole (MP) is more prominent than the lateral pole (LP).
    • The articular surface on the posterior aspect of the condyle is greater than on the anterior aspect.
  23. TMJ components from temporal bone
    • STF: stylotympanic fissure. Fissure btwn styloid and tympanic part
    • Mandibular (glenoid) fossa
    • AE: articular eminence
  24. Characterized by the mode of movement, TMJ is a _________ joint.
    • ginglymoid = hinging (rotation)
    • arthroidial = gliding (translation)
  25. Three components of TMJ
    • condyle
    • mandibular fossa
    • articular disc - dense fibrous connective tissue; no nerves; no blood vessels
    • loose connective tissue
    • highly vascularized & innervated
  27. Ligament functions
    • Protect structures
    • Passive restraining devices
    • Limit movements
  28. Ligaments
    • Collateral (Discal; medial/lateral) Ligaments
    • Capsular Ligaments - extends anteriorly to include the articular eminence and encompass the entire articular surface of the joint.
    • Temporomandibular Ligament
    • Sphenomandibular Ligament
    • Stylomandibular Ligament
    • limits the protrusive movement, especially stylo-
  30. Muscle of mastication (nerve)
    • Temporalis
    • Masseter
    • Medial “Internal” Pterygoid
    • Lateral "External" Pterygoid - inferior & superior heads
    • All supplied by the mandibular branch of CN V (Trigeminal)
  31. Temporalis
    • Origin: lateral surface of skull
    • Insertion: coronoid process of ramus
    • Function: elevates & retrudes the mandible
  32. Masseter
    • Origin: zygomatic arch
    • Insertion: lateral surface of the mandibular angle
    • Function: elevates & protrudes mandible, forms a sling together with Medial Pterygoid muscle
  33. Medial Pterygoid
    • Origin: medial surface of the lateral pterygoid plate
    • Insertion: medial surface of the mandibular angle
    • Function: elevates & protrudes mandible
  34. Lateral Pterygoid - inferior head
    • Origin: lateral surface of lateral pterygoid plate
    • Insertion: neck of condyle
    • Function: bilateral - protrudes, depress the mandible; Unilateral - lateral to the contralateral side mandible
  35. Non-masticatory depressor
    Digastric Muscle
  36. Lateral Pterygoid - superior head
    • Origin: Sphenoid bone
    • Insertion: articular capsule, disc
    • Function: move the disc during protrusion
    • Porion - Orbitale
    • Porion: upper margin of ear canal
    • upper member of the articulator
  38. Bennet angle
    • 0-30 degrees
    • represents the medial wall of glenoid fossa
  39. Condylar Guidance
    Sagittal angle represents the superior wall of the glenoid fossa
    • Vertical Dimension of Occlusion (VDO): Distance between maxilla and mandible when teeth are in contact.
    • Vertical Dimension of Rest (VDR): Distance between maxilla and mandible when the mandible in a physiologic rest position.
    • VDR-VDO=Inter Occlusal Distance (IOD) or Free Way Space: 2-4 mm (avg 3 mm)
  41. Protrusive contacts
    • Distal Inclines of Maxillary Teeth occlude with Mesial Inclines of Mandibular Teeth
    • Maxillary Distal Inclines of Lingual Supporting Cusps
    • Mandibular Mesial Inclines of Buccal Supporting Cusps
    • Condyle moving down and forward with disc (follows shape of articular eminence)
  42. Laterotrusive & Mediotrusive
    Side to Side Position and the contact on the anterior teeth
  43. Movement of the Man supporting cusp and Max contact site during protrusive, retrusive, laterotrusive, and mediotrusive movement
    • M and M
    • D and D
    • B and B
    • LM and LM
  44. Rotational movement of mandible rotate along _____.
    • axis of rotation/horizontal transverse (/hinge) axis
    • within the inferior cavity of TMJ (between the superior surface of the condyle and the inferior surface of the articular disc)
  45. Translational movement
    • A movement in which each point of the moving object has simultaneously the same velocity and direction
    • Occurs within the superior cavity of TMJ (between the superior surface of the articular disc and the inferior surface of the articular fossa, i.e. between the disc-condyle complex and the articular fossa)
  46. Border movement
    reproducable and limited by the ligaments and the articular surfaces of the TMJs, as well as by the teeth.
  47. Functional Movement
    • Intraborder movement.
    • Determined by the responses of the neuromuscular system
  48. Mandibular movement envelope in sagittal plane
    • Starts from CR: hinge movement (20-25mm), limited by TM ligaments
    • Maximum opening: 40-60mm; limited by capsular ligaments
    • Anterior closing border movement: limited by Stylomandibular Ligament; w/ the contraction of the inferior lateral pterygoids
    • Superior contact border movement: limited by teeth morphology
  49. Superior contact border movement in sagittal plane
    • CR->ICP: forward and upward in 90% population (~1.25mm)
    • ICP->edge to edge: forward and downward: limit by contact of incisal
    • ...
  50. Functional movement in sagittal plane
    • Begin at or 2-4 mm below the ICP at the physiologic rest position of the mandible or Postural Position, PP.
    • Chewing stroke like a tear drop, open in posterior direction and close in anterior direction
    • Functional Opening & Closing
  51. Posselt’s Envelope of mandibular movement
    By combining mandibular border movements in the three planes, a three-dimensional envelope of motion can be produced that represents the maximum range of movement of the mandible.
Card Set
Occlusion - Midterm
Occlusion - Midterm