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
For upper dentures - which areas have the best support and why - what is their significance?
Hard palate ranging from rugae/incisive papilla to just before fovea palatini and vibrating line/post dam - includes the torus (along the middle) and the alveolar ridge crest with gingival vestige (gingival remnant)
-This area is where bone is more horizontal and provides more support than lowers, when adjusting fit surfaces need as much contact as possible to gain max support
*Check diagram for BDS5 REM PROS session 1 - page 5
For lower dentures - which areas have the best support and why? HINT similar reason as uppers
Alveolar ridge crest and buccal shelves adj to this up to the labial frenum
-Bone is most horizontal - when adjusting fit surfaces - as much contact is needed as possible in these areas to gain max support
*Check diagram for BDS5 REM PROS session 1- page 6
What can you used to determine where the denture is contacting the tissues the most and check support?
Pressure indicating materials to tell you where contacts are (of all the areas highlighted in the previous flashcards)
What is a flabby ridge and how can you assess if one is flabby
Fibrous replacement of bone - softer
Moveable and floppy
Palpate the ridge to see whats happening
Denture problems - what helps prevent loose dentures?
- Saliva layer - bw denture and soft tissues –> adhesion and suction = peripheral seal
- Muscles - press against polished surfaces holding in place (design denture in neutral zone or denture space)
- Even occlusal scheme - keeps denture in place during function e.g biting tog and no interferences with each other/w natural teeth
- Gravity - lower denture (also keeps weight of the upper denture down)
- Clasps - grip onto natural teeth (direct retention)
- Rests - used to prevent denture rotation (indirect retention)
How does xerostomia cause denture problems,
3 solutions to the problem
Dry mouth, less saliva –> SALIVA acts as natural lubricant through adhesion and cohesion between the denture surface and the soft tissues/ridge - see page 9 diagram
- Saliva replacements - sprays or rinses
- Saliva stimulants - sugar-free sweets or gum
- Denture related - adhesives, refurbishing fit surface or soft lining (a soft compressible material on layer of denture - shock absorber and increases comfort)
What are common problems encountered with peripheral seal?
Flange:
Flange is too thin - needs to fill width of sulcus - so no air enters
Flange is too thick - not enough saliva for seal/suction
Flange is too long - pushes onto muscles and mucosa - these push back and denture comes out
Flange is too short - more air allowed - poorer seal
Post dam:
Extend far back enough to include HAMULAR NOTCHES BUT keep it on non-moveable - but displaceable tissue (so not soft palate)
THINK about comfort for pt
Common muscular control problems
SHAPE AND VAVOURABILITY for muscles of oral cavity:
If dentures are placed too buccally or too lingually - opposing forces of muscles will push denture out
E.g upper denture too buccal - cheek will push it down, lower denture too lingual - tongue will push it out
Account for tongue space too to prevent this
What is the importance of a correct occlusal scheme and what would this involve
If uneven/unstable occlusion –> dentures slide about and knock into each other during function - INTERFERENCE
If correct occlusion - this means dentures bite together evenly in RCP - even contact throughout arch - wont move sideways on closing
What is a common occlusal error that result in a shift with dentures - what stage should this be checked?
If first contact - post tooth only - uncomfortable bite for patient - naturally horizontally shift in RCP
CHECK for this at jaw reg and tooth try in stages and manage
What common hard and soft tissue problems do denture wearers face?
Dental caries
Traumatic ulcer
Denture granulomas
Candida infection - denture stomatitis
