Assessing dentures and supporting tissues Flashcards
Define support
Resistance to movement towards the supporting tissues (mucosa)
What 4 things maximise denture support
- Firm mucosa (not a flabby ridge)
- Denture fits supporting tissues properly (teeth and mucosa)
- Maximum coverage (mucosa)
- Metal rests (healthy teeth and well distributed)
What properties of metal rests maximise support in a metal denture?
Metal rests - healthy abutment teeth and well distributed evenly across arch (4 legs to table)
How do you know/check if denture has good support
- Press on occlusal surface (both sides at once) see if it moves towards tissues or wobbles
- Check how much mucosa is covered by fit surface/flange of denture
- Look for signs of mucosal trauma (imprints, inflammation, denture stomatitis, granulomas etc)
Define retention
(What is the main difference with stability)
Resistance to movement away from supporting tissues AT REST
Stability - DURING FUNCTION
What things maximise denture retention?
- Denture fitting supporting tissues properly (mucosa and teeth)
- Peripheral seal (complete dentures - adhesive saliva layer) and correct flange extension into sulci (partial and complete)
- Size of DBA - denture bearing area - peripheral seal needs proper extension i.e post dam, helps tongue retention etc
- Polished surfaces have suitable contours for muscles - occupy neutral zone
- Direct retainers and guide planes (teeth)
- Indirect retainers (teeth and mucosa)
- Gravity (lower) and low denture weight (upper)
- Saliva (quality and quantitity)
- Precision attachments
How do you know/check if a denture has good retention?
- See if it moves when a pt is at rest (lips apart)
- Pull denture away from supporting tissues (check if tongue is holding denture)
- Push up on anterior teeth and see if it drops at the back (upper complete dentures)
Define stability
(What is main difference with retention)
Resistance to movement towards or away from tissues in any direction DURING FUNCTION
Retention - AT REST
What 4 things maximise denture stability
- Good support
- Good retention
- Denture occupies ‘neutral zone’ (cheeks, lips, tongue)
- An occlusal scheme that avoids knocking dentures out of place in lateral excursions (interference from natural or denture teeth) - adequate jaw reg and articulation etc
How do you know/check if a denture has good stability
- Press on occlusal surface (one side only - mimics bolus of food) and see if moves in a any direction
- Mvmt during speech
- Mvmt during eating
What is the neutral zone and what technique is useful for recording it?
It is the area where outward forces of the tongue are neutralised by inward forces of lips and cheeks during function
Piezography (check later decks)
Anatomical considerations - how does a large ridge height help dentures?
- Better support and retention (larger DBA)
- Better stability if support and retention are good
- Better stability in sideways direction - flanges resist lateral displacement due to tall ridge
- Easier to judge where denture teeth should go - want similar to natural dentition
Anatomical considerations - how does short ridge height cause problems in dentures?
- Smaller SA - support and retention compromised
- More likely to move sideways during function (shallow sulci/compromised impression accuracy)
- More difficult to position denture teeth
Anatomical considerations - how does mucosa thickness and consistency affect dentures?
- Thick fibrous (moveable) tissue not so good for support - displacement BUT want firm ridges
- Very thin mucosa - easily damaged and not good at cushioning occlusal forces
Anatomical considerations - natural tooth arrangement and how does this affect dentures?
- No of teeth to replace
- Where are they - kennedy classification
- Are they healthy, restorable, poor prognosis? - for AB teeth and clasps and future tooth loss and additions