Complete Dentures - RETENTION AND STABILITY Flashcards
Why is treatment to edontulous pts so important?
- To maintain alveolar bone levels
- Restore function
- Aesthetics
- Fix sunken cheeks
*Speech
*self-esteem/confidence
What can prosthetics help with?
They can help patients with oral cancer who couldn’t eat and chew
They can help patients with a cleft palate who find it difficult to swallow in order too stop the contents of food and drink going up into the nasopharynx (Obturator seals of the oropharynx and nasopharynx
What is Domiciliary visits
Going to houses/nursing homes to provide treatment
What’s RVD?
Resting vertical dimension
What is ICP?
Inter-cuspal postion - When a patient is in occlusion
What are primary impressions for?
Casting models and special tray
Aim is to define (outline, Make obvious) the denture support area) for special tray
Upper - Record all palate and all ridge the maxillary tuberosities and frontal attachment
** Lower** - All of the ridge down on the inside to the mylohyoid ridge and frenal attachments as well.
What are secondary impressions for?
Cast models
Create record rims
How do you carry out Jaw registration after creating record rims?
You insert the record rims in patients mouth |(upper)
Create an imaginary line, from the ala of the nose to the tragus of the ear.
You measure the occlusion using the fox plane to see if its parallel to the ala-tragus line.
Check fullness of flange and reduce any wax if needed.
What is freeway space?
Between 2-4mm and is the space between dentures at rest
RVD - Occlussal VD = Freeway space
What is the definition of Centric Relation?
The mst anterior superior position of the condylar disc assembly within the glenoid fossa which is irrespective of teeth
After Jaw registration is completed what stages remain
- Try in (process to finish)
- Fit
What is retention?
Forces which stop the denture from falling out (During speech or coughing)
What is stability?
Helps the denture stay in place during function (Eating/Chewing dentures not moving around)
What difference is there with retention in complete dentures and partial dentures?
Partial dentures have undercut, guide planes, clasps but complete dentures have Border Seal and Post-dam
What is Border Seal?
The junction between flange and cheek creates a border seal to prevent air/food and water from getting underneath denture and displacing it
Border seal is similar to suction.
What is Post-Dam?
At the back we don’t have a border seal therefore a post dam is needed which is a raised little area that pushes into the tissues slightly to provide air tight sea.
(Doesn’t press too hard to cause trauma or pain but may leave an indent)
It is done on hard palate and not too far back.
How do you create an effective border seal? And when is the best time to create one>
Ideally done when taking secondary impressions.
1) Non-perforated tray (as perforated will leave holes for air
2) Use green/pink stick to compress the post dam area and record the functional width of the sulcus in the tuberosity region (in the molar area
Why is saliva important in border seal?
Saliva has effects of adhesion and cohesion allowing them to be sticky and effective in creating moisture to create a nice border seal
Why and how do you check salivary flow in patients?
Patients who suffer from Xerostomia associated with drugs/radiotherapy too head and neck could have damaged salivary glands/ Rheumatoid arthritis/sjorgrens disease.
Check salivary flow by swiping inside of cheek as it should be smooth. If not then artificial saliva will be needed or ask patient to chew on gum
What muscular forces help and how?
Buccinator and Orbicularis oris and ** TONGUE** help keep the seal intact and push denture into place and the tongue helps hold denture from dropping out.
Does Muscular control matter? Which patients may struggle with this?
Yes as it can affect seal of denture. Pt with Parkinson’s, stroke or motor neurone disease may struggle with this.
What is the neutral zone and when is it relevant?
Neutral Zone: Area in mouth where during function, the forces of the tongue pressing outward are neutralised buy the forces of the cheek and lips pressing inwards helping with retention.
What key aspects should be present in a Lower dentures? And what muscle should you be aware of?
Neutral zone. E.g if dentures aren’t in the neutral zone they will be displaced.
Leaving off the 7’s can provide the tongue with more space and stabilising the lower denture
Make teeth narrower can reduce tongue cramping
Lower anterior teeth are influenced by muscles such as mentalis - If the teeth Are too far forward the muscle may push the denture backwards making the denture feel loose.
What methods of accessory retention are there for patients with retention issues?
Implant treatment
Fixatives
How does Implant Treatment help with Accessory retention?
Implants need bone: Patient may need bone graft
Used to maintain bone, give support nand provide retention
Improved bite force
Improved chewing ability
What are the advantages and disadvantages of fixatives on retention?
Make saliva more viscous
Lead to increased levels of plaques
PT shouldn’t use on daily basis
BUT
Can give Improved seal
Increased feeling of security
Improved maximum bite force
Improved quality of life
Why is Denture Stability important?
Denture should be able to stay in place.
If not stable can cause Rubbing on tissue, Pain, Looseness, Inability to chew, Speech problems, and social/psychological effects
* If they move can lead to broken border seal so lack of stability can cause lack of retention
* can affect chewing so patient wont be able to eat certain foods
What is an example of good occlusion in a denture?
Balanced occlusion - Teeth meet evenly on both sides at the same time when the pt closes
Balanced Articulation - During lateral movements the contacts are shared across as many teeth as possible
What is an example of bad occlusion in a denture?
Premature contact - Biting forced are so strong when pt closes mouth teeth will come together but only because the top denture will fall down and patient will complain of top denture being loose.
What can happen if bad occlusion?
Denture hyperplasia - from continued trauma over time
Denture Falls out or feels loose
Ways to check occlusion?
Check for premature contacts using articulating paper
Hold dentures with fingers in upper and lower and ask pt to bite together to prevent dentures lifting up or down
What is the ideal position when setting up teeth in the lab?
Upper teeth with palatal cusps directly over the ridge and lower teeth with central fossa over the ridge
What are the 2 types of patient curves?
Curve of Wilson/monson (from the front)
Curve of spee (from the side)
Why is the curve of Monson important for balanced articulation?
In order to have balanced articulation, a patient moves their jaw side to side and the teeth on the left and right should still be meeting. The condyle moves down when moving to each side causing the curve
what is important in protrusion? (When the front jaw moves forward)
During protrusion we want teeth to stay together as well
(Curve of spee)
0
What doe the lower teeth look like when set up acccording to the curve of spee?
Posterior teeth curve upwards and outwards as you go to the back
Which articulation can be used to check for articulation?
Average value (can be moved side to side and front to back)
What is near the lower premolar region?
Mental nerve
