Special Techniques with Complete Dentures

Question 1

What is the pt’s main concern regarding dentures? What to consider with this?

Answer 1

Denture security = retention and stability of denture

- Consider occlusal, polished and fitting surface

Question 2

What is retention?

Answer 2

Resists displacement in an axial direction

Question 3

How to achieve retention with CD?

Answer 3

Cohesion between denture oral mucosa

Peripheral seal

Question 4

How to achieve dentures with an RPD?

Answer 4

Cohesion between denture oral mucosa

Tooth undercut

Question 5

How to assess denture retention?

Answer 5

Push denture into place and pull downwards and it stays in place = static retention
Pt move lips and cheeks = if denture moves under or overextentions (flange too long or not enough frenal relief)
If pt opens mouth and upper denture drops = due to occlusal disharmony
Get pt to slide in all directions = if denture moves = lack of balanced articulation
Want as many teeth as possible to stop denture displacing

Question 6

What compromises retention with CD?

Answer 6

• Poor denture adaptation - old or badly made or/and (can suddenly become loose due to bone resorption = denture becomes overextended)
• Unfavourable supporting anatomy
• fibrous ridges = prevents stability
• atrophic alveolus, post surgery and/or
• Dry mouth - lack of cohesive seal

Question 7

Define denture stability

Answer 7

Ability to resist those forces attempting to displace it in directions, other than at right angles to the supporting tissues (in a non-axial direction)
- Size and shape of the residular alveolar ridge

Question 8

When a pt has a torus palatinus, what should you consider?

Answer 8

Finish denture before torus = reduction in retention as less surface area used
Can surgically remove the torus
Use fixative

Question 9

What issues can a bulbous ridge cause?

Answer 9

Problems with retention = undercuts present - get denture to finish slightly shorter than the maximum depth

Question 10

What to optimise for stability?

Where do you want the most occlusal contacts?

Answer 10

Periphery
Occlusal surface and polished surface

Periphery:

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

Occlusal surface must achieve:

• Balanced occlusion: even bilateral contact between opposing surfaces in RCP - a static position
• • You want most contacts on premolars, less on molars, less on canine, none on anteriors
• Balanced articulation: Even and mutual stability in all lateral and protrusive movements - a dynamic relationship
• Slide L and R you want at least one contact on the opposite site

Polished surfaces

• Concave polished surfaces = enable musculature to stabilise the dentures - especially where lower lip and chin meet - if not will interfere with neutral zone
• Removal of undercut on the lingual surface to prevent lingual displacement

Question 11

What compromises stability?

Answer 11

Uneven or un-favourable occlusal contacts

Lever arm forces that cause a tipping effect

Question 12

What causes a lack of denture stability?

Answer 12

Poorly designed occlusal patterns (CDs)
Retained teeth (RPDs)

Question 13

Aims of denture adhesives?

Answer 13

Help with denture retention
To enable effective function
Avoid social embarrassment

Question 14

Problems with denture adhesives?

Answer 14

Achieved with minimal inconvenience:

• Alteration of taste
• Difficulty of application and removal

Poor fit = more adhesive required = more saliva can get under denture and wash away adhesive

Question 15

Barriers to denture adhesives?

Answer 15

Need often associated with failure
Customer confusion
Effectiveness is patient driven and variable
Problems of
- Perception, altered taste, altered sensation
- Difficult removal, unpredictable failure and don’t last long
Does not focus on user
Poor instructions for use

Question 16

When to use: Thin film denture adhesive - super wernets (powder)?

Answer 16

Dentures are well adapted
Denture bearing anatomy is unfavourable for effective retention
There is a need to enhance salivary cohesion

Question 17

When to use: Volume fillers denture adhesive (polygrip)?

Answer 17

Dentures are ill fitting
Poor adaptation between denture and mucosa
There is a need to fill the gap

Question 18

What is the neutral zone?

Answer 18

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

• Mandibular anterior region = lower lip
• Mandibular posterior sextants = tongue cramp (lack of space for tongue)

Question 19

What is the neutral zone technique?

Answer 19

1. Heat cured base after definitive imps for registration
2. Set registration rims in even contact
3. Remove most of the wax from 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 mouth
6. Pt touches palatal surface of upper anterior rim with tip of tongue, occlude, smile and relax

Question 20

Pre-contact check record - what does it do?

Answer 20

To ensure occlusal balance
To remove discrepancies that occur as a result of errors during the recording of the jaw relations and the processing of the denture

Record where the first contact is - pre-contact

Question 21

What is the BULL rule?

Answer 21

Buccal upper lower lingual
When you move right contacts on buccal cusps can flatten
Ensures maintenance of balancing size contacts

Question 22

What teeth do you want to occlude when a complete denture is opposed by natural teeth?

Answer 22

Get contacts in posterior region when protruding

Do not want canine guidance or disclusion on posterior teeth