Week 7 - Ear Bow Transfer & CR Record

Question 1

Face (Ear) Bow is the ___ point of reference.

Answer 1

3rd

Question 2

In addition to the ear bow, what do you need for an ear bow transfer?

Answer 2

Bite forks
Mounting Jig
Leaf Gauge

Question 3

How is an arbitrary hinge axis determined?

Answer 3

13mm anterior to tragus on tragus-canthus line

Question 4

How is a kinematic hinge axis determined?

Answer 4

It is the actual axis determined by a pantograph

Question 5

What is the significance of an ear bow transfer?

Answer 5

1. Relates maxillary cast to the terminal hinge axis (mandibular condyles)
2. Orients the maxillary cast correctly in space using a third point of reference (occlusal plane)
3. Is aligned parallel to the interpupillary line (reference)
4. Permits mounting of the maxillary cast on a semi-adjustable articulator
5. The mandibular cast is mounted using a centric relation (CR) record.

Question 6

What is Centric Relation?

Answer 6

The maxillomandibular relationship in which the condyles articulate with the thinnest avascular portion of their respective disks with the complex in the anterior-superior position against the shapes of the articular eminencies. This position is independent of tooth contact. CO = MI

Question 7

What are the methods of recording CR?

Answer 7

• Bilateral manipulation
• Chin point guidance
• Anterior deprogrammer

Question 8

What is required to record CR?

Answer 8

• A material that is fast setting, thin, soft, dimensionally stable and easily verifiable. (Blu-Mousse by Dentaegis)
• No teeth can be touching & it must be along the arc of rotation of the mandible.

Question 9

What is the influence of anterior guidance?

Answer 9

• 20 degree = incisal guidance has more influence?

- 30 degree = articular eminence has more influence?