Prosthodontics (removable) Flashcards
what is definition of complete dentures?
A removable dental prosthesis that replaces the entire dentition and associated structures of the maxilla or mandible
list some effects of endentulism?
o Loss of masticatory function
o Appearance
o Self esteem
o General health effects
o Quality of life
o Speech
o Ridge resorption
o Soft tissue changes to lip & chin
o Reduction in face height
o Not only do you lose teeth you lose bone and soft tissue
describe resorption after extraction of teeth?
Occurs rapidly after extraction particularly in 1st six months
Individually variable
May be dependent on pre-extraction status of teeth
Occurs throughout life
what are the 2 types of variations in ridge resorption?
cawood and howell 3 and 5
list some feature a patient will experience from complete dentures?
o Inefficient at mastication
o Require good neuro-muscular control
o Stability of a lower complete often compromised by tongue movements
o Appearance/speech can be sub-optimal
list some of the main reasons to make a patient endentulous?
- caries
- periodontal disease
- severe and debilitating tooth wear
- failing dentitions
- occlusal collapse
- appearance
- head and neck chancer - chemo
- pre chemo
- pre transplant
- pre cardiac surgery
- at patients request
what are diff methods of complete denture construction?
conventional and replica or both
questions to ask pt about their denture history?
- No previous denture wearing experience
- Previous denture wearing experience
- What does your patient think?
- Age of dentures?
- Matched set?
- Most recent set worn?
- When 1st denture?
- How many sets dentures?
- Material/soft lining?
- Success or failure?
what should you especially look for in intra oral exam?
- Support in edentulous areas
- Mouth opening – trismus
- Peri-oral opening
- Support – Resistance of vertical movement of a denture towards the ridge
what are some things patient could be suffering from after old denture?
- denture stomatitis
- angular chelitis
- dental hyperplasia
what do you check during denture examination in mouth?
- Occlusal planes: anterior & posterior
- Vertical Height – RVD – OVD = Freeway Space
- Occlusion recorded correctly in retruded contact position (RCP)
- Lip support
- Overextension or Under extension
- Retention; Stability; Adaptation
describe intercuspal position?
The complete intercuspation of the opposing teeth independent of condylar position, sometimes referred to as the best fit of the teeth regardless of the condylar position
describe retruded contact psoition?
Guided occlusal relationship occurring at the most retruded position of the condyles in the joint cavities.
RCP is the most reproducible position
In complete dentures we do not use ICP as there is no opposing teeth
describe retention of denture?
The resistance to displacement of a denture away from the ridge
describe stability of denture?
Ability of a denture to resist displacement by functional stresses
describe adaption of denture?
the degree of fit between a prosthesis and supporting structures
what do you check fro denture examination out of mouth?
- base extension
- tooth position
- excessive wear of denture
- alterations since insertion e.g repairs, additions
- denture hygiene
describe what primary impressions should do?
o Should “accurately record clinical relevant landmarks without excessive tissue distortion”
how can stock trays be modified?
- putty
- soft red wax
- red composition
- ## green stick
how do you reduce extension of stock trays?
- acrylic bur and straight handpiece
what are limitations of stock trays?
o Trays are not made to measure
o Peripheral extensions - often over or under extended
o Limited sizes available
o Require master impressions to record denture bearing area with accuracy
how do you record a primary impression?
Explain procedure to patient
Select trays - use tray with most appropriate extension
Assess this visually in the mouth by manipulating cheeks, lips and tongue
Change tray size if too big or small
Reflect – Are you happy with the tray – Use it no modification; Are you unhappy – add material or remove part of tray or both, select appropriate material
Ideally there should be ~4mm between tray flange and denture bearing area
Apply thin layer of adhesive over tray AND putty / wax/ composition and allow to dry
Mix alginate (dental nurse) Load tray (you) with alginate [see videos]
Seat loaded tray in mouth
Border mould muscles eg: cheeks and lips whilst constantly supporting tray
Once alginate set remove it with sharp sudden movement
how do you do border moulding the lower anterior lingual sulcus?
sticking the tongue out to get correct sulcus depth
how do you assess an impression?
- Are all the edentulous areas included?
- Are the sulci areas to be included in the denture recorded fully?
- Are deficiencies present due to air inclusion??
- Is the impression fit for purpose or not?
describe master impressions?
o Record denture bearing area, functional depth and width of sulci
o Use custom made special (individual) trays prescribed after primary impressions
how do you take master impressions?
o Clinical procedure:
Check extension - ought to be ~2mm short of sulcus depth to allow border moulding
Mould Stops: (Greenstick)
* position
* maintain spacing for material
* allow consistent placing of tray
INSERT TRAY in mouth TO MOULD STOPS - use greenstick WITH CARE!!
* Check extension and modify if necessary – add or remove material – add use greenstick; remove similar to stock tray with acrylic bur & straight handpiece
* Apply thin layer of adhesive - dry
* Less alginate required than primary impressions
* Excess material may obstruct airway or prevent seating of tray - retching
* Pre-pack where necessary – high arched palate/tuberosities
* Support tray throughout procedure
* Border moulding
* Assess the impression like primary impressions but more accuracy required
* Rinse with water and keep moist with damp paper towel
what do you aim for with master impressions?
o Well rounded borders
o Minimal air blows & none in important areas
o Impression centrally placed in tray
o Ensure all clinically relevant areas included
what are some special tray materials?
VLC resin PMMA (acrylic)
* pre-rolled sheets
* easy to mould
* very rigid - sometimes problems removing from model
Self-cure PMMA (acrylic) –
* problems rolling an even layer
what are advantages of special trays?
Accurate peripheral extension
Uniform thickness of material
Reduced amount of material -Less discomfort as tray fits individual mouth
Records denture bearing area more accurately
how to disinfect impressions?
Rinse in running water to remove saliva, blood or debris
Disinfect - for 10 minutes in disinfectant solution
Rinse thoroughly (having put on clean gloves)
Cover alginate impressions with damp paper towel
Label and place in a plastic laboratory bag
On laboratory prescription indicate that impressions have been disinfected which MUST be signed by supervising clinician
Take to laboratory asap for casting
Standard Operating Procedures (SOPs) often change, keep alert for changes
describe first clinical stage of replica dentures?
- clean dentures modify with greenstick if needed
- replicate using lab putty and stock trays out of mouth
- remove dentures from mould, clean and return them to patient
- disinfect moulds
- take to lab with prescription
describe first lab stage of replica blocks?
lay shellac base onto fitting surface of mould
pour molten wax into moulds
once wax set remove completed wax replica blocks on shellac bases
describe 2nd clinical stage of replica dentures?
master impressions and jaw bite reg
- disinfect replica blocs
- upper master imp on replica block
- lower master imp on replica block
- jaw reg with both record blocks
- choose shade (and moulds)
- disinfect registered blocks/imps
- take to lab with prescription
what is 2nd lab stage of constructing replica dentures?
cast impressions, mount casts and set up
- cast impressions
- mount casts on articulator
- set upper and lower teeth in wax
- tidy up wax work
what is 3rd clinical stage of constructing replica dentures?
try in (trial)
- disinfect try in
- try in the teeth set in wax
- try in checks
- re-register/make other changes as required
- disinfect try in
- take to lab with prescription for (retry) or finish
what are try in checks?
o Vertical dimension of occlusion
o Even contact in retruded contact position
o Lip support
o Occlusal planes – anterior/posterior
o Lower teeth over ridge Speech
o Retention & stability
o Base extensions
o Appearance
what is 3rd lab stage for constructing replica dentures?
process (finish) dentures
- wax up
- flasking
- deflasking
- trim and polish denture
what is 4th clinical stage of constructing replica dentures?
insertion (finish)
- disinfect dentures
- insert and insert checks
- denture wear and cleaning instructions
- arrange review visit (1-2 weeks)
what are insertion checks?
o Vertical dimension of occlusion
o Even contact in retruded contact position
o Speech
o Retention & stability
o Base extensions
o Appearance
o Comfort
what is 5th clinical stage for constructing replica dentures?
review
- review and review checks
- adjust (ease) if required
- arrange further review if required
what are review check?
- pain/redness/ulceration
- function
- aesthetics
- speech
- recheck occlusion/vertical dimension
what is 1st clinical stage for constructing conventional complete dentures?
primary impressions
- take primary imps using stock trays
- disinfect
- take to lab with prescription
what is first lab stage in constructing conventional dentures?
primary casts and special trays
- pour casts
- remove impression from casts
- make special trays from primary cast
typically what normally sized spacer do you use?
3mm
what is 2nd clinical stage for conventional complete?
master imps
- disinfect special trays
- master imp on special tray
- mark post dam for upper
- disinfect imp
- take to lab with prescription
same for lowers but no post dam
what is 2nd lab stage for conventional completes?
master casts and record blocks
- pour master casts
- make record blocks
what is 3rd clinical stage for conventional dentures?
jaw (bite) reg
- disinfect record blocks
- register the occlusion; choose shade, setting and mould
- disinfect registered blocks
- take to lab with prescription
what is 3rd lab stage in construction of convetionals?
mount casts and set up
- put registered blocks on holding casts
- mount on articulator
- set up teeth
- setting up upper anterior teeth
- setting up lower anterior teeth
- setting up posterior teeth
what is 4th clinical stage in conventional completes?
try in (trial)
- disinfect try in
- try in teeth set in wax
- try in checks
- re-register/make other changes as required
- disinfect try in
- take to lab with prescription for retry or finish
what are try in checks for conventional dentures?
o Vertical dimension of occlusion
o Even contact in retruded contact position
o Lip support
o Occlusal planes – anterior/posterior
o Lower teeth over ridge
o Speech
o Retention & stability
o Base extensions
o Appearance
what is 4th lab stage for conventional completes?
process (finish) dentures
- wax up
- flasking
- deflasking
- trim and polish denture
what is 5th clinical stage for conventional completes?
insertion (finish)
- disinfect dentures
- insert and insert checks
- denture wear and cleaning instructions
- arrange review visit (ideally 1-2 weeks)
what are insertion checks for conventional completes?
o Vertical dimension of occlusion
o Even contact in retruded contact position
o Speech
o Retention & stability
o Base extensions
o Appearance
o Comfort
what is 6th clinical stage for conventional completes?
review
- review and review checks
- adjust (ease) if required
- arrange further review if required
what are the review checks for conventional completes?
- pain/redness/ulceration
- function
- aesthetics
- speech
- recheck occlusion/vertical dimension
what is an impression?
o A reverse or negative form of the tissues which is converted into a positive model/cast using plaster or stone or a mixture of both plaster and stone.
how to assess fit of stock trays?
o 1. Look inside mouth and guestimate the correct size
o 2. Try in tray & look inside mouth
Too small – flanges hit the ridge
Too large – stretches the mouth or feels uncomfortable or cannot get it in the mouth
what are limitations of stock trays?
o Rarely fit the mouth accurately
o Often require modification
o May be difficult to obtain necessary border seal
o Remember – Do not overload trays; Occasional pre-packing
Always prescribe for special trays
where do you position yourself for impression taking?
o Upper: Stand behind
o Lower: Stand in front
o Both: Get the chair height correct for your height (change height between U & L)
o Patient: Sitting up not flat
what is the technique to taking impressions?
1. Rehearse tray insertion before loading then rotate the loaded tray into patient’s mouth
2. Use firm pressure to seat the tray home
3. Border moulding whilst supporting the impression with other hand
4. Lower – tongue movement; Upper – partial mouth closure
5. Do not remove until set
6. Remove the impression
7. Inspect the impression
Note: Talk to your patient throughout; if retches deep breaths through nose, tilt head forward & calm patient – Effective communication