Relines, Repairs and Additions Flashcards
(46 cards)
1
Q
What is a reline?
A
Adding new base material to the tissue surface of an existingdenture in aquantity sufficient to fill the space which existsbetweenthe originaldenturecontour and the altered tissue contour
2
Q
What is a rebase?
A
Replacing the entiredenturebase material of an existing denture – only done in complete dentures.
3
Q
Is a reline or a rebase typically done chairside?
A
Relines.
4
Q
3 types of relines?
A
- Temporary.
- Soft.
- Permanent
5
Q
Are relines done chairside or in the lab?
A
Can be done in both - the more resilient relines tend to be done in the lab.
6
Q
2 advantages of temporary soft lining?
A
- Improves fit of denture.
- Provides soft lining to minimize further trauma/ allow tissues to heal.
7
Q
Name an example of a temporary lining?
A
Coe-comfort.
8
Q
3 indications for the use of temporary relines?
A
- When tissues are grossly inflamed - place tissue conditioner and record impressions a few weeks later once the tissues have settled.
- Post immediate dentures (as there will be some initial resorption around tissues where teeth have been extracted).
- After implant surgery (adjust the denture so it will seat over the implant and line it).
9
Q
Another term for a temporary reline?
A
Tissue conditioner.
10
Q
3 cases in which a soft lining can be useful?
A
- Patients with parafunctional habits (ex. grinding - reduces the load onto the lower ridge).
- Very atrophic ridges.
- In Cancer/ cleft patients (obturators).
11
Q
3 downsides of soft linings?
A
- Plasticizer leaches (irritation + hardens with time).
- Deteriorate with time.
- Harbour microorganisms.
12
Q
4 types of soft lining material?
A
- Heat and self cured acrylics.
- Heat and self cured silicones.
13
Q
What do acrylic soft linings contain? Give a named example.
A
- Heat cured acrylic: powder is methacrylate based, activated by benzoyl peroxide in liquid with monomer and plasticizer.
- Self cured acrylics: as above but tertiary amine acts upon benzoyl peroxide instead of heat - ex. COE-SOFT.
14
Q
What do silicone soft linings contain? Give a named example.
A
- Heat-cured silicones: processed against acrylic. Contain a siloxane material and a filler of silica.
- Self-cured silicones: similar to impression materials for composition and setting.
15
Q
What material are permanent relines usually made of? Where are they usually placed? (chairside vs lab).
A
- Heat cured acrylic.
- Lab.
16
Q
4 indications for the use of permanent relines?
A
- Peripheral seal problems.
- Correction of errors following inadequate master impression (denture drops down during fit stage).
- Immediate/ post immediate dentures (would place the permanent lining MONTHS after extraction after the tissues have healed. In between a temporary lining would be placed).
- Prolongs lifespan of some older dentures (teeth not worn etc).
17
Q
What are the steps of a reline/ rebase technique?
A
- Remove undercuts from dentures BEFORE taking the impression (model will break when trying to remove denture from model if fail to do so).
- A wash impression is take inside the denture (use denture as a “special tray”). Use a CLOSE MOUTH TECHNIQUE to ensure the occlusion remains unchanged.
- Disinfect as normal and complete lab card asking for denture to be rebased.
- Lab would pour impression in STONE.
- Lab will make a plaster overcast which goes over the occlusal surface of the teeth.
- Denture can be removed and the working model (where denture will be placed) can be seen.
- Carve post-dam at the junction of the hard and soft palates.
- Remove the fitting surface and palate to allow space for the new acrylic.
- Re place cut back denture onto the overcast.
- Put all 3 parts back together (overcast, model, denture) and use sticky wax to hold the denture in place to the plaster overcast.
- Fill gap with wax.
- The overcast can be removed.
- The palate is added in wax.
- Denture is flasked using the Dundee injection method.
- Wax is removed (boiled out), separator is applied and acrylic is injected into the mold.
- Place in a clamp and process.
- Once processed the denture is ground to shape and polished.
- Rebased (relined) denture is sent to clinic. Carry out similar checks to insertion and arrange a review 1-2 weeks later.
18
Q
What materials can be used to take the wash impression for a rebase/ reline technique?
A
- Silicone impression material.
- Zinc oxide eugenol.
19
Q
What can be done to the post dam in a retching patient?
A
Place a second post dam further inside. Thus if the palatal extension has to be reduced, there is still a post dam on the denture.
20
Q
Why is there a gap formed after the fitting surface and palate are removed and the model, denture and overcast are placed back together?
A
The gap was previously filled by the impression material.
21
Q
What are the two functions of the overcast?
A
- Maintain the position of the denture relative to the model.
- Maintain the vertical dimension.
22
Q
Steps to the Dundee Injection flasking technique?
A
- Mix acrylic and when ready place into plastic bag.
- Insert plastic bag containing acrylic into the injector.
- Position the flask and the injector. Turn the clamp handle slowly until acrylic flows out of the flask.
- Place flask in clamp and process.
- Once processed, the denture is ground into shape and polished.
23
Q
3 things to check when trying in a rebased denture?
A
- OVD
- Occlusion
- Speech
24
Q
5 common types of denture fractures?
A
- Midline (especially in complete dentures).
- Tooth detaches from denture base.
- Loss of flange.
- Acrylic saddle detaches from Co/Cr baseplate.
- Clasp fracture/bent.
25
8 reasons why dentures fracture.
1. **Impact.**
2. **Acrylic in thin section** (ex. over palate).
3. **Work hardening of metal.**
4. **Parafunctional habits.**
5. **Occlusion - Deep overbite** (thinner acrylic).
6. **Soft linings** (take up a lot of space that hard acrylic would otherwise take up)
7. Denture processing problem - **porosity**.
8. **Bonding** between tooth and base acrylic or acrylic and CoCr.
26
What are the steps for fixing a simple repair? Give an example of a simple repair.
- Ex. Midline fracture of complete dentures - fractured pieces can be located together (no missing pieces).
- Disinfect, send to lab (no need for impression), cast poured, fractured area removed, new acrylic processed.
27
What are the steps for repairing a denture when a piece of it is missing? Give an example.
- Ex. part of acrylic flange lost.
- Impression taken with fractured denture in mouth. LEAVE DENTURE IN IMPRESSION.
- Disinfect.
- Pour cast.
- New acrylic processed into defect.
28
What is a challenging repair?
- Acrylic to cobalt chromium.
29
4 things that can be used to connect acrylic to cobalt chrome?
- Retentive tags.
- Solder on tags.
- 4-META
- silicoat Co/Cr
all help retain acrylic to CoCr.
30
2 materials for temporary repairs? Where are these done?
- Self cure acrylic.
- Cyanoacrylate glue (super glue)
Usually done chairside however only TEMPORARY fixes.
30
What happens if the two parts of a broken denture are superglued together in the wrong way?
- The whole superglued area must be removed and repositioned to a model for that patient.
31
Super glue?
Cyanoacrylate glue.
32
When may a denture be unrepairable (2)?
- Broken into many pieces.
- Multiple broken pieces missing.
33
3 things that can be added to dentures
- Tooth
- Clasp
- (Flange)
34
3 types of additions
- Immediate addition
- Post-immediate addition
- Retention (ex. clasp).
35
What is an immediate addition?
When a tooth is lost after denture construction and the tooth is added on the day of tooth extraction.
36
How are immediate additions performed?
- Record an impression with the denture in place.
- Send the impression and denture to the lab.
- Laboratory would remove the tooth to be extracted fro the cast and add it onto the denture.
37
What is a post-immediate addition?
When a tooth is lost after denture construction YET a tooth is added to the denture at a later date (after 2-3 weeks).
38
How are post-immediate additions performed?
- Get patient to return 2-3 weeks after extraction and record impression with the denture in place.
- Give impression and denture to the laboratory and they would add the tooth.
39
What is a retention addition?
When denture retention is inadequate a clasp is added to try to improve retention.
Usually wrought SS.
40
How is a retention addition performed?
- Take an impression with the denture in place.
- Give the impression with the denture in place to the laboratory.
41
What is required for additions?
Additions require an impression of the arch with the denture to be added to IN THE MOUTH during the impression.
42
Can additions be done chairside?
OCCASIONALLY can do additions chairside in **self-cure acrylic** yet this is TEMPORARY.
43
Is it easier to add to Co/Cr or acrylic? Why is this important for treatment planning?
- Much easier for ACRYLIC.
- Hence if patient likely to need extractions in the future, opt for acrylic denture.
44
What is an occasion when you can't add to a Co/Cr denture?
Ex. lower incisor addition when using a lingual bar connector.
45
4 things that may be needed to perform acrylic additions onto Co/Cr?
- Retentive tags.
- Solder on tags.
- 4-META
- Silicoat
