clinical stages Flashcards
What are the stages of making a complete denture
- Primary impressions
- Cast model and create special tray (LAB)
- Secondary impressions
- Cast models and create record rims (LAB)
- Jaw registration
- Mount on articulator and set up teeth (LAB)
- Try in
- Process to fit (LAB)
- Fit
What makes a good impression
An impression should record the entire functional denture bearing area to ensure maximum support, retention + stability for the denture during use
What anatomy should an upper primary impression have
- Hamular notch
- Vibrating line
- Fovea palatinae
- Torus paltaltinus
- Mucogingival line
- Buccal sulcus
- Palatal gingival vestige
- Labial sulcus
- Buccal frenum
- Labia frenum
- Incisive papilla
- Palatal rugae
What anatomy should a lower primary impression have
- Retromolar pad
- Lingual sulcus
- Lingual frenum
- Buccal frenum
- Labial frenum
- Labial sulcus
- Buccal shelf
- Buccal sulcus
9 Pear shaped pad
What is the vibrating line
Junction between the immovable and movable tissue of the soft palate
How can we identify where the vibrating line is
Get the patient to say ahhh
What is the fovea palatinae
The bilateral indentation near the midline of the palate
How is the fovea palatinae formed
Coalescence of several mucous gland ducts
Where is the fovea palatinae found
Posterior to the hard/ soft palate junction (vibrating line)
What is the torus palatines
Harmless bony ingrowth/ exostosis located on the hard palate
What is the palatal gingival vestige
Raided fibrous ridge on the palatal surface of upper residual ridge
What can the palatal gingival vestige be used to do
Distinguish palatal mucosa from vestibular buccal mucosa
can be used a a guide in position maxillary teeth
How should a denture sit
- Sit on firm tissue
- Accommodate for bony undercuts
- Upper should extend to the vibrating lien for a post dam
What criteria must a primary impression fulfil
- Must record tissues without distortion
- Must be completed with minimal discomfort to patient
- must cover max denture bearing area
- Free of significant voids
What makes a bad denture
- Significant voids
- Under extension
- Over extension
- Impression material not adhering to tray
- Not covering full denture bearing area
- Knife edged areas
What is impression compound made up of
- Resin
- Plasticiser
- Filler
How is impression compound used
- Softened in a water bath
- Placed in patients mouth then back in water bath to soften
What is the advantage of impression compound
- Non toxic
- Easy to use
- Can be re softened
- Muco displace
- Corrects gross tray problems
What are the disadvantages of using impression compound
- Poor surface detail
- Poor dimensional stability
What are the advantages of alginate
- Easy to use
- Well tolerated
- Elastic
- Viscosity can be altered
- Good surface detail
- Mucostatic
What are the disadvantages of alginate
- Poor stability after setting
- Cannot be added to
- Increases risk of drying out, shrinkage and syneresis
- Increased risk of swelling and imbibition
- Poor tear resistance
- Requires adhesive to stick to tray
- Unsupported alginate
What is alginate made up fo
Irreversible colloid
What is impression compound made up of
- Resins (paraffin wax, beeswax and shellac)
- Filler (Talc and chalk)
- Plasticiser (stearic acid)
What is silicone putty made up of
Polydimethyl siloxane and platinum catalyst
What are the advantages of silicone putty
- Easy to mix
- Relatively easy to use
- Moderate surface detail
- Well tolerated
- Elastic
- Supports its own weight
- Muco compressive
What are the disadvantages of silicone putty
- Expensive
- Needs tray adhesive
- Long setting time
- Hydrophobic
What do we put in out lab prescription after taking the primary impression
- Draw tray outline approx 2mm short of periphery of impression
- Decide on need for spacing or close fitting design
- Upper handle slightly labially proclined
- Lower vertical handle and finger rests in premolar region
What do we need to add onto special trays to take a secondary impression
Stops
What are the purposes of stops
- Allows for space for material to flow out
- Prevents build up of hydrostatic pressure
- To ensure we get an even layer of material
what are the steps we take for an upper occlusal rim
- Line upper rim with shellac
- Correct lip support
- Adjust incised level by getting the patient to smile
- Ensure occlusal rim is parallel with inter pupillary Line
- Ensure occlusal rim is parallel with Ala tragal plane
What is the ideal naso labial angle
90-100 degrees
How can we alter lip support
By adding or removing wax
How can we ensure the occlusal plane is parallel to inter pupillary line
- Using a fox guide plane
- Standing in front of the patient and asking them to look at your nose
What are the steps we take for adjusting a lower occlusal rim
- Line with thin light cure acrylic
- Measure RVD using willis gauge
- With both the upper and lower rim adjust the height to the correct OVD
- Mark on midline with score levels in premolar region
- Cut v notches on lower and upper models
- Place silicone adhesive on lower model
- Guide patient into RCP and get then to occlude
- Seal models with blu mousse
What should the patens RVD be
At rest teeth should be slightly apart
What should the free way space be
2-4mm
How is the free way space calculated
RVD - OVD = FWS
After adjusting the occlusal rims what do we do
Select :
shade
size
shape of teeth
What are the aims of wax try in
- To identify and correct any errors prior to finish
- Allow patents to assess appearance of dentures so any appropriate modifications can be performed
How is a wax try in placed to assess for errors
- On an articulator
- in the patients mouth
What do we check for on an articulator
- Balanced occlusion
- Balanced articulation
What do we check for when assessing balance of occlusion
All teeth meet evenly
What do we look at when assess an upper or lower wax try in individually
- Retention
- Stability
- Extension of base
- Relationship to neutral zone
How to we assess wax try ins relationship to the neutral zone
Check curve of wilson and ridge position
What do we look at when assessing an upper and lower wax try in together
- Appearance
- Occlusion
- Free way space
What can happen if the base of the max try in is over extended
Denture will displace
What can happen if the base of the wax try in is under extended
Poor retention for upper dentures
How can we correct an over extended wax try in base
By decreasing over extended flanges
How can we correct an under extended wax try in base
Correct by taking a wash impression
or the better option is to go back to the secondary impression stage
Where should the flanges extend to on a wax try in
Extend beyond the full depth of the sulcus
What does accurate and correct flange extension ensure
Creates seal which will increase retention
makes movement of air and saliva slower decreasing displacement of denture
What can happen if the flange width is too wide
Can decrease stability and traumatise soft tissues
air and saliva will move over the denture faster increasing risk of dispalcement
What is a too wide flange caused by
Excess green stick
How do we assess the lip support of a patient at the wax try in stage
Look at the patient from all angles
ask the patient for their opinion
What should the Casio labial angle be
90-110 degrees
How much of the incisors should be see at rest
2-3mm
What happens to the levle of the incisor seen at rest as age increases
Lip becomes less elastic so patient shows less teeth
What must we ensure the smile lien and midline are parallel to
Alar tragal line
How do we correct an unfavourable incisal level
Go back to the max rim phase
What are some specific things we look for when assessing a lower try in
Discomfort from the renal attachments, tori and mental nerves
What is the neutral zone
The area where balanced forces from surrounding muscles (eg tongue and cheeks) prevents the denture from unseating in function
Where should the tongue sit at rest when the denture is placed
Tongue should lie just behind the lower anterior teeth
How do we measure RVD
Get patient to place lower denture only
ask patent to relax
use willis gauge
Take thought eh method of occlusal assessment for a wax try in
- Visual
- Patients perception
- Articulating paper
How do we assess OVD
- Insert the lower denture and measure RVD
- Insert upper denture and measure OVD
- Assess free way space at this point
What should you do if your free way space is inaccurate
1, Remove teeth and re record occlusion
OR
2, Go back to wax try in stage
Other than occlusion and aesthetics what else should we check when both wax try in are in the mouth
Speech
How do we assess the patients speech with was try in
Ask patient to count from 60-70
If patients teeth drop then there’s a problem with retention
If patients teeth click then there’s a problem with the free way space
How do we assess the patients speech with was try in
Ask patient to count from 60-70
If patients teeth drop then there’s a problem with retention
If patients teeth click then there’s a problem with the free way space
What does it suggest if the patietn struggles with saying the letter s
OVD is excessive or absent
What does it suggest if the patietn struggles with saying the letter s
OVD is excessive or absent WWHt
What does it suggest if the patietn struggles with saying the letter s
OVD is excessive or absent
What is an average free way space
2-4mm
What can excessive free way space case
- Increased load on dentine bearing tissues
- Soreness to mucosa
- Increased load toTMJ
- Teeth clock together while speaking
- Teeth constantly in contact
What can a lack of free way space cause
- Over-closure to get teeth to meet
- Difficulty eating
- No teeth show
What must we ensure we achieve by the end of the denture giving appointment
New denture should be as comfortable as possible:
- No pain experienced by patients during insertion removal or occlusal contact
- Teeth meet evenly
- Dentures are retentive with good extension
In regards to patient understanding what should we check they know before leaving with their new dentures
- How to control the dentures
- Benefits and limitations of dentures
- Denture hygiene
What do we check for on the denture surface before giving it to patietn
1, Sharp edges
2. Acrylic pearls
3. Undercuts
What do we check for upon insertion of new dentures
- Fit and occlusion
- Occlusion
- Assess OVD
- Free way space
- Appearance
What can be some common causes of pain from a denture
- Undercut flange which will traumatise mucosa
- Acrylic spicules, nodules or sharp edges and surfaces
How can we assess occlusion with dentures in situ
- Tactile visual assessment
- Feedback from patient
- Articulating papaer (last resort)
when should we recall a patietn who we have given a new denture to
1 week
