Registration Stage III Selection Of Teeth

Question 1

What are the helpful hints to selection of teeth?

Answer 1

1. Listen to the pts views
2. Use photographs/favoured Dentures if possible
3. Use the aesthetic central base to assist in the delineation of the maxillary anterior aesthetic arc
4. Select lower anterior teeth to complement the upper anteriors
5. Select posterior teeth using aesthetic and functional criteria

Question 2

What can help the clinician in tooth selection

Answer 2

Pre extraction records : photographs, casts, radiographs, relative with similar appearance

Question 3

The six upper anterior teeth should _________

Answer 3

Appropriately support the upper lip
Occupy that area of the upper anterior arch ordered by the corners of the mouth
Allow for individualisarion where indicated rotation imbrication or spacing

Question 4

What can be used to the determine the height of the central incisor tooth

Answer 4

Scribing on the wax blocks the high smile line(ACB)

Question 5

What factors influence the selection of posterior tooth form

Answer 5

Occlusion
Aesthetics
Stability

Question 6

What are the three types of teeth available from the lab

Answer 6

Teeth with cusps
Cuspless teeth
Hybrid teeth

Question 7

Can balanced occlusion and articulation be created in teeth without cusps

Answer 7

Balanced occlusion
Possible and these teeth generally take less lab time to set up

Balanced articulation a truly balanced articulation is not possible with these teeth

Question 8

Why might using teeth with cusps be contraindicated

Answer 8

In implant borne cases
Where there is a flat lower ridge
If there is a slide present

Question 9

Can balanced occlusion and articulation be created with hybrid teeth

Answer 9

Occlusion: some grinding may be necessary

Articulation: lingualised occlusion should be used ie maxillary palatal cusps are intended to maintain contact with their antagonists

Question 10

What is William’s guideline to tooth selection

Answer 10

Relating upper central incisor form to frontal appearance of the face
Has no scientific credence

Question 11

How did Lang classify posterior tooth moulds?

Answer 11

Anatomic
Non anatomic
Zero degree teeth
Cuspless teeth

Question 12

What is the definition of each of the following according to the glossory of prosthodontic terms
Anatomic
Non anatomic
Zero degree
Cuspless teeth

Answer 12

Anatomic: teeth that have cuspal inclination greater than 0 and tend to replicate occlusal anatomy. Such teeth may have cuspal angles set to 20, 30, 33, or 45

Non anatomic: teeth designed in accordance with mechanical properties rather than from anatomic standpoint

Zero degree teeth: posterior teeth that have 0 cuspal angles

Cuspless l
Teeth:teeth designed without cuspal prominence on the occlusal surface ie inverted cusp teeth

Question 13

What is the most common combination of selected denture teeth

Answer 13

Upper teeth with cusp angles of 20 degrees with modified buccal cusps and lower non anatomic teeth without cusps

Question 14

How does selection of teeth depend on the pts masticatory habits

Answer 14

If the pt only performs vertical mandibular movements then it is possible that Cuspless teeth will suffice. If however, the pt performs ruminatory mandibular movements then teeth with cusps will be required for balanced articulation and thus stable Dentures.

Question 15

How can examination of existing Dentures assist the diagnosis

Answer 15

If the Dentures have occlusal surfaces that are evenly worn ie flat this is usually suggestive of vertical chopping mandibular movements whereas much greater wear of the maxillary buccal cusps especially is suggestive of ruminatory mandibular movements