Tooth Selection for Complete Dentures Flashcards
When is the shade and mould selected?
**Jaw Registration **
With consideration at:
*Assessment
*Try-in
*Re-try
*Fit
What are the steps of jaw reg?
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
What are the considerations of tooth selection for anterior and posterior teeth?
Anterior
- Function
- Speech – some sounds require teeth to contact upper anterior teeth
- Appearance
**Posterior **
Must fit in neutral zone within denture bearing area
What are the dentist factors in tooth selection?
size of facial skeleton/skeletal class
ageing
previous/ current dentures
physiological pigmentation of gingivae
opinion/perception
What are patient factors in tooth selection?
influence of family/others
lifestyle goals
relationship goals
psychological factors
perceptions of ageing
What are materials used for artifical teeth?
- Acrylic
- Porcelain – doesn’t adhere to acrylic
- Composite resin based
- Combinations
What is colour washout?
looking at same item too long - no longer see colour
best to glance away and back
What is illuminant metameric failure?
shade of teeth appears different under different lightening
What is observer metametric failure?
get second opinion
observers may perceive colours differently
How can the shade of gums be affected?
- Physiological pigmentation
- Range of “gum” shades needed
- Layers of pigments often needed
- Can use Minute Stain to paint acrylic
What should you do when selecting the mould?
use ruler to measure existing denture and match to mould guide
What is done for patial dentures?
often don’t choose mould and ask lab to follow size/shape
What is digital smile design?
- Software based
- Determined by the “Golden Proportion”
- Does not suit every patient, nor is it what everyone wants – exercise caution
What is the rule of width of nose?
- “Inter-canine width should be width of nose”
- But nostrils vary
- May work in some cases but not always right
When is change prescribed on lab card?
*
Diastema
*
Rotation
*
Recession
What will the incisal level, midline and occlusal plane be determined by in relation to record block?
- 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
What biometric guide can be used for tooth positioning?
how does it work?
- 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
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What is the selection and position of teeth dependant on?
Ridge
Neuromuscular control
Reproducibility of occlusal position
How are lower posterior teeth set and why?
- 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
How does lingual flange occur?
how can it be fixed?
- Teeth set over ridge
- Wide, square teeth
- Tongue gets under flange and lifts denture
- Remove excess with bur
What can be done for tongue space?
remove premolar or second molar if require more space for tongue
What should the occlusal plane height be?
- In harmony with tongue
- Tongue movements with try-in insitu
How should upper posterior teeth be set?
- Slightly buccal to ridge
- Without compromising border seal
- If too buccal will complain of:
Biting cheek
Denture destabilising
What are anatomical cusped teeth and what should they be used in?
33 degree angle
use in RCP
What are cuspless teeth and what should they be used in?
0 degree angle
Use if you can’t replicate RCP
Teeth can slide over each other
Poorer aesthetics
What is balanced occlusion/ balanced articulation?
- 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
