Recording Jaw Relation

  1. What is Christensen Phenomenon?
    The separation of posterior teeth when anterior teeth touch in forward protrusion movement.

    Remember: Christensen Ph. Is undesirable for denture fabrication.
  2. Centric relation is:
    • Maxillomandibuar relationship
    • in which condole articulate with the thinnest portion of disk 
    • with the complex in the anterior posterior position
  3. According to Boucher, centric relation is:
    The most posterior relation of the mandible to the maxillar from which lateral movement can be made
  4. Difference between “centric relation” and “centric occlusion”:
    • Centric relation: condyle - glenoid fossa 
    • Centric occlusion: upper teeth - lower teeth

    Remember: CO can be either maximum intercuspation or not.
  5. What is freedom in centric (aka long centric)?
    What is its important in complete denture?
    Freedom in centric is when patient have maximum intercuspation in both CR and some where near CR.

    In a situation when CR is not precise (elderly, disable patient), freedom in centric is accommodated.
  6. The importances of centric relation record: (4)
    • repeatability
    • able to arrange teeth in right position
    • able to adjust condylar guidance right
    • with hinge axis record able to get right relationship between maxillar and hinge axis
  7. What is “hinge axis record”?
    What instrument is used to make “hinge axis record” in complete edentlous patient?
    • Relationship between maxillar and hinge axis
    • Arbitrary face-bow

    Remember: kinematic face-bow is more precise but not practical when placing on edentulous.
  8. The face-bow have to be parallel with ... plane.
    Frankfort horizontal plane (infraorbital notch - Targus)

    Remember: Camper’s is horizontal plane drawing from alar of nose to targus of ear
  9. Advantage and disadvantage of CR recording using interocclusal record at vertical dimension
    • Record at VD:
    • adv. = ไม่เกิดการคลาดเคลื่อนเวลาทด pin เมื่อนำ bite ออก
    • dis. = U/L oc rim อาจชนกันเวลา regist

    • Remember: record befor reaching VD (ไม่ตัด oc rim)
    • adv. = ไม่มีการชนของ oc rim
    • dis. = เวลานำ bite ออก แล้วทด pin ลงมา มันจะคลาดเคลื่อน ถ้าไม่ได้ทำ hinge axis record
  10. What material could be use for interocclusal registration?
    • Wax
    • Zincoxide eugenol (best?)
    • Silicine
    • Impression plaster
  11. 2 eccentric relation records are:
    and their purposes are:
    • protrusion interocclusal record: condylar guidance angle
    • lateral interocclusal record: Bennett angle or lateral side shift of the mandible)
  12. When should protrusion interocclusal record be made? (2)
    • After try in oc. rim (before CR record), or
    • After try in anterior teeth
  13. How do we find Bennett angle when lateral interocclusal record is usually imprecise.
    Using Hanua formulae to calculate Bennett angle from condylar guidance angle.

    L = (H/8) + 12

    • L is Bennett angle 
    • H is horizontal condylar guidance angle
  14. When eccentric interocclusal record cannot be obtained, what numbers should be used?
    • We use average angles:
    • condylar guidance angle = 30 degree
    • Bennett angle = 15 degree
    • Incisal table = 0 degree
  15. Concern about using non-adjustable articulator (class I) ?
    The interocclusal record need to be very thin!
  16. The advantages of arcon over nonarcon articulator (semi adjustable articulator: class III)
    • Easy to understand the movement
    • Less error when using interocclusal record

    • Remember: It represents real anatomy
    • glenoid fossa - upper member
    • condyle - lower member
  17. What circumstance should we use fully adjustable articulator (class IV)?
    • Multiple occlusal restoration (crowns)
    • Need to restore at new VD
  18. How do we make interocclusal record and hinge axis record when using fully adjustable articulator?
    • Graphic record (dynamic jaw relation)
    • Kinematic facebow
  19. Why non-adjustable articulator is not suitable for CD fabrication?
    ,and what type of articulator will be?
    • Non-adjustable articulator is not accommodated with balanced occlusion
    • Using with interocclusal record and facebow, semi-adjustable articulator (non arcon) is the most suitable for CD making.
  20. What type of articulator the Hanua model H is?
    Semi-adjustable (non arcon)

    Remember: Hanua model H is not accommodated with lateral intrusion record. Bennett angle is calculated from condyle angle
  21. Which value the dentists can adjust by themselves?
    • Incisal guidance angle
    • Dentists will decide how steep the angle should be considering anterior esthetic and phonetic

    Remember: the incisal guidance angle should be as low as possible so less steep cusp posterior teeth can be used.
Card Set
Recording Jaw Relation
MU Complete Denture