Tooth Selection for Complete Dentures

Question 2

When is the shade and mould selected?

Answer 2

**Jaw Registration **

With consideration at:
*Assessment
*Try-in
*Re-try
*Fit

Question 3

What are the steps of jaw reg?

Answer 3

Step 1: Check retention/stability of upper block. Adjust extensions if required
Step 2: Adjust upper record block as per LIMBO
(Lip support, incisal level, mark midline, buccal corridors, occlusal plane)
Step 3: Check stability of lower block. Adjust extensions if required
Step 3: Define lower tooth position & horizontal jaw relationship
Step 4: Measure vertical dimension & establish face height
Step 5: Record registration
Step 6: Select shade, mould, & setting

Question 4

What are the considerations of tooth selection for anterior and posterior teeth?

Answer 4

Anterior
- Function
- Speech – some sounds require teeth to contact upper anterior teeth
- Appearance

**Posterior **
Must fit in neutral zone within denture bearing area

Question 5

What are the dentist factors in tooth selection?

Answer 5

size of facial skeleton/skeletal class
ageing
previous/ current dentures
physiological pigmentation of gingivae
opinion/perception

Question 6

What are patient factors in tooth selection?

Answer 6

influence of family/others
lifestyle goals
relationship goals
psychological factors
perceptions of ageing

Question 7

What are materials used for artifical teeth?

Answer 7

• Acrylic
• Porcelain – doesn’t adhere to acrylic
• Composite resin based
• Combinations

Question 8

What is colour washout?

Answer 8

looking at same item too long - no longer see colour
best to glance away and back

Question 9

What is illuminant metameric failure?

Answer 9

shade of teeth appears different under different lightening

Question 10

What is observer metametric failure?

Answer 10

get second opinion
observers may perceive colours differently

Question 11

How can the shade of gums be affected?

Answer 11

• Physiological pigmentation
• Range of “gum” shades needed
• Layers of pigments often needed
• Can use Minute Stain to paint acrylic

Question 12

What should you do when selecting the mould?

Answer 12

use ruler to measure existing denture and match to mould guide

Question 13

What is done for patial dentures?

Answer 13

often don’t choose mould and ask lab to follow size/shape

Question 14

What is digital smile design?

Answer 14

• Software based
• Determined by the “Golden Proportion”
• Does not suit every patient, nor is it what everyone wants – exercise caution

Question 15

What is the rule of width of nose?

Answer 15

• “Inter-canine width should be width of nose”
• But nostrils vary
• May work in some cases but not always right

Question 16

When is change prescribed on lab card?

Answer 16

*
Diastema
*
Rotation
*
Recession

Question 17

What will the incisal level, midline and occlusal plane be determined by in relation to record block?

Answer 17

• Incisal level will be determined by height of upper record block
• Midline will be determined by mark on record block
• Occlusal plane will be determined by record block adjustment

Question 18

What biometric guide can be used for tooth positioning?

how does it work?

Answer 18

• Alma bite gauge
• Works on averages and is a guide only
• Uses incisive papilla as fixed point
• Determines that tip of anterior teeth should be: 5.5mm anterior to incisive papilla horizontally and 7mm below incisive papilla vertically

Question 19

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What is the selection and position of teeth dependant on?

Answer 19

Ridge
Neuromuscular control
Reproducibility of occlusal position

Question 20

How are lower posterior teeth set and why?

Answer 20

• Lower posterior teeth must be set over the crest of the ridge
• If not they will be placed out-with the denture bearing area
• This means forces will not be directed appropriately – SUPPORT
• Be mindful of the tongue destabilizing the denture - STABILITY

Question 21

How does lingual flange occur?

how can it be fixed?

Answer 21

• Teeth set over ridge
• Wide, square teeth
• Tongue gets under flange and lifts denture
• Remove excess with bur

Question 22

What can be done for tongue space?

Answer 22

remove premolar or second molar if require more space for tongue

Question 23

What should the occlusal plane height be?

Answer 23

• In harmony with tongue
• Tongue movements with try-in insitu

Question 24

How should upper posterior teeth be set?

Answer 24

• Slightly buccal to ridge
• Without compromising border seal
• If too buccal will complain of:
  Biting cheek
  Denture destabilising

Question 25

What are anatomical cusped teeth and what should they be used in?

Answer 25

33 degree angle
use in RCP

Question 26

What are cuspless teeth and what should they be used in?

Answer 26

0 degree angle
Use if you can’t replicate RCP
Teeth can slide over each other
Poorer aesthetics

Question 27

What is balanced occlusion/ balanced articulation?

Answer 27

• Teeth meeting evenly both sides in occlusion and lateral excursions
• Difficult to achieve laterally and may not be necessary
• Easier with small width of teeth
• Check at try in