CD - Function and Stability Flashcards
What is the pts main concern with CD?
Denture security = retention and stability
Consider 3 surfaces: occlusal, polished, fitting
What is denture stability
Ability to resist those forces attempting to displace it in directions, other than at right angles to the supporting tissues
- Size and shape of the residual alveolar ridge has an impact
Issues with ridges?
Atrophic fibrous ridge
Torus palatinus
Bulbous ridge
What impacts denture stability?
What needs to be optimised to achieve denture stability?
Impacted by size and shape of residual alveolar ridge
Need to optimise: peripheral seal, occlusal surface is favourable (will not dislodge denture), polished surface
Why is the denture periphery important for stability?
Avoid encroachment onto muscle insertions: mylohyoid, buccinator, genioglossus, mentalis
Undertake functional moulding with impressions
What must the occlusal surface achieve for denture stability?
Balanced occlusion: even in bilateral contact between opposing surfaces in RCP - a static position
Balanced articulation: even and mutual stability in all lateral and protrusive movements - a dynamic relationship
How do polished surfaces achieve denture stability?
Concave polished surfaces = enable musculature to stabilise the dentures
Removal of undercut on the lingual surface = prevents lingual displacement
What is the neutral zone?
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)
How to find the neutral zone (neutral zone impression technique)?
- Request a heat cured base after definitive imps for registration
- Set registration rims in even contact
- Remove most of the wax from the anterior region
- Apply adhesive to cut the surface and replace the missing wax with a small amount of still alginate
- Place in the mouth
- Get pt to touch the palatal surface of the upper anterior rim with the tip of the tongue, occlude, smile and relax
- Similar procedure carried out in posterior region
SUMMARY
- Remove wax from reg rims from anterior region and replace with still alginate
- Place in mouth
- Get pt to touch palatal surface of upper anterior rim with tip of tongue, occlude, smile and relax
Pre-contact check record function?
Ensures occlusal balance
Removes discrepancies that occur as a result of errors during the recording of the jaw relations and the processing of the denture
= method for re-registering coincidence of retruded and intercuspal positions
Take just before they meet or 1 tooth has just met
How to check the contacts for balanced occlusion?
Horseshoe articulating paper
Can deepen fossas with acrylic bur until 1st contact is on the first molars
What is the BULL rule?
Ensures maintenance of the balancing side contacts
(buccal of upper, lingual of lower
CD when opposed by natural teeth - what’s different in making the dentures?
Impressions as normal
Registration - upper anterior teeth of CD will overlap the lower anterior natural teeth, support if often needed posteriorly
Wax try in normal
Placement - ensure a check record is carried out and that balance is achieved between the natural teeth and the denture in occlusion and lateral excursions
Function of articulating paper?
Identify premature contacts
Achieve even contacts in lateral excursions
How to take impressions for flabby ridges?
Different impression technique - window where the flabby ridge is and use a mucostatic impression material (silicone) on the flabby bit and mucocompressive for the rest (ZOE)
