Function and stability

Question 1

What is the denture security a function of?

Answer 1

Retention - staying in the mouth and stability - rocks when eat and drink, moves forwards and backwards

Question 2

What are the 3 surfaces that need to be considered in denture security?

Answer 2

Occlusal
Polished
Fitting

Question 3

What is denture stability?

Answer 3

Ability to resist those forces attempting to displace it in directions other than at right angles to the supporting tissues

Question 4

What is stability affected by

Answer 4

Size and shape of the residual ridge

Question 5

What do you need to optimise to improve denture stability?

Answer 5

Periphery
Occlusal surface
Polished surface

Question 6

How can the periphery be optimised?

Answer 6

Avoid encroachment onto muscle insertions: mylohyoid, buccinator, genioglossus and mentalis
Undertake functional moulding with impressions

Question 7

How do you optimise the occlusal surface?

Answer 7

Must achieve balanced occlusion
Even bilateral contact between opposing surfaces in RCP, contacts all the way around
And balanced articulation
Even and mutual stability in all lateral and protrusive movements

Question 8

How do you optimise the polished surfaces?

Answer 8

Concave polished surfaces will enable the musculature to stabilise the dentures
Removal of the undercut on the lingual surface to prevent lingual displacement

Question 9

What is the neutral zone?

Answer 9

Site where opposing surfaces exerted by lips and cheeks and tongue are in balance

Question 10

Why is being in the neutral zone important?

Answer 10

will get instability

Question 11

In the anterior lower mandibular region why is being in the neutral zone important?

Answer 11

Lower lip will force the denture backwards

Question 12

In the posterior lower mandibular region why is being in the neutral zone important?

Answer 12

Posterior sextants - get tongue cramp - lack of space for tongue
Want the lower teeth to be over the residual ridge

Question 13

What is the technique for finding the neutral zone?

Answer 13

1. Request a heat-cured base after definitive imps for registration
2. Set registration rims in even contact
3. Remove most of the wax in the anterior region
4. apply adhesive to the cut surface and replace the missing wax with a small amount of stiff alginate
5. Place in the mouth
6. Patient to touch the palatal surface of the upper anterior rim with the tip of their tongue, occlude, smile, relax
7. Similar procedure carried out in the posterior region
   mould the alginate into a position where it is comfortable with movement of the lips and tongue

Question 14

What is the pre-contact check-record for?

Answer 14

To ensure occlusal balance
A method for re-registering coincidence of retruded and intercuspal positions
To remove discrepancies that occur as a result of errors during the recording of the jaw relations and the processing of the denture

Question 15

What is the method for pre-contact check record?

Answer 15

When put dentures together in hand, can get a nice occlusion

When put in mouth still have the position but dont know if the soft tissues are in contact

Question 16

What is the problem with combination syndrome?

Full upper and partial lower denture

Answer 16

Retention and stability is a problem

Upper ridge becomes fibrous and flabby then get different movement of the soft tissue

Question 17

What is the clinical technique for complete dentures opposed by natural teeth?

Answer 17

Impression as normal
Registration - be aware the upper anterior teeth of the denture will overlap the lower anterior natural teeth, support is needed posteriorly - I-bar on the RPD
Wax try-in as normal
Placement - ensure check record carried out and that balance is achieved between the natural teeth and the denture in occlusion and lateral excursions

Question 18

How can you check you have balanced occlusion chairside

Answer 18

Use articulating paper to identify the contacts
Need to do pre-centric or grinding chairside to get balance
Use a bur to deepen the fossae and repeat until contacts include first molars at least
Now the anterior contact relationship os reflected posteriorly
Dentures are now fully seated and can move in all excursions = occlusal stability