Week 9: Wax Rims

Question 1

What is the purpose of wax rims

Answer 1

To record the relation between the maxilla and the mandible

Question 2

What are some ideal characteristics of wax rims

Answer 2

stable
High strength
Create a vacuums seal in Mx arch
Accurate fit
free of air pockets

Question 3

What are the standard dimensions of Full endentulous Mx and Md wax rims

Answer 3

MX:
Anterior rim height 10mm above Incisive papilla
Posterior rim height 8mm above tuberosity
Width of rim is 8mm

MD:
10mm Above the anterior alveolar ridge
Width of rim is 8mm

OR

MX: 22mm from deepest part of the anterior sulcus

MD: 19mm from deepest part of the Anterior sulcus

Question 4

Describe briefly characteristics of partial wax rims

Answer 4

Rims only found on edentulous ares.
Rims finish at the occlusal height of abutment teeth
Rim width is 8mm or matching dentition
WILL NOT ATTAIN SUCTION DUE TO AIR LEAK

Question 5

what are the vertical dimensions that are essential for jaw relation

Answer 5

Vertical dimensions at occlusion (VDO)
Vertical dimensions at rest (VDR)
Freeway space (2-4mm)

Question 6

what is centric relation and how does it differ from centric occlusion

Answer 6

centric relation:
the most posterior position of the mandible in relation to the maxillary at an established VDO

Centric occlusion is slightly anterior to centric relation, however in endentulous patients centric occlusion cannot be recorded.

Question 7

describe the neutral zone, and what happens when teeth are not set inside this zone

Answer 7

is formed by balances forces exerted by the muscles of the lips, cheek, tongue and occlusion.

• when teeth are set outside of the neutral zone, it causes instability, cheek biting, denture displacement, lack of lip support

Question 8

what is fox plane

Answer 8

The Fox Plane determines the relationship of planes of the wax rim to the inter-pupilary (campers line) and ala-tragus plane.

Fox plane is used to establish plane of occlusion during fabrication of prosthesis

Question 9

What 3 things are required to stop alterations to the maxillary rim?

Answer 9

1. Occulsal plane is established
2. incisal edge is established
3. lip support is sufficient

Question 10

what technique can be used to help patients get into centric relation position

Answer 10

using the button technique by placing a button of wax on the posterior palatal wax rim surface.

Question 11

what is the working time of PVS for jaw relation

Answer 11

60 secs

Question 12

what is the function of articulators

Answer 12

These articulators allow lab technicians to perform protrusive, lateral movements for adjusting occlusion to match the similar movements performed in by the TMJ.

Question 13

what is the key difference between semi adjustable articulators and hinge type articulators

Answer 13

Semi adjustable articulators
- allow for vertical dimension adjustment and allow for the protrusive and lateral movements

hinge articulators
only allow for simple opening and closing movements

Question 14

what is the condylar guidance angle and the Bennett angle

Answer 14

condylar guidance angle: 30
Bennett angle: 15

Question 15

what is the function of a facebow

Answer 15

used to transfer the relationship between the maxilla and the condyle from the patient to an articulator in order to closely align the maxillary model to the axis of movement of the condyles