Relines, Repairs and Additions Flashcards
What is a reline?
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
What is a rebase?
Replacing the entiredenturebase material of an existing denture – only done in complete dentures.
Is a reline or a rebase typically done chairside?
Relines.
3 types of relines?
- Temporary.
- Soft.
- Permanent
Are relines done chairside or in the lab?
Can be done in both - the more resilient relines tend to be done in the lab.
2 advantages of temporary soft lining?
- Improves fit of denture.
- Provides soft lining to minimize further trauma/ allow tissues to heal.
Name an example of a temporary lining?
Coe-comfort.
3 indications for the use of temporary relines?
- 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).
Another term for a temporary reline?
Tissue conditioner.
3 cases in which a soft lining can be useful?
- Patients with parafunctional habits (ex. grinding - reduces the load onto the lower ridge).
- Very atrophic ridges.
- In Cancer/ cleft patients (obturators).
3 downsides of soft linings?
- Plasticizer leaches (irritation + hardens with time).
- Deteriorate with time.
- Harbour microorganisms.
4 types of soft lining material?
- Heat and self cured acrylics.
- Heat and self cured silicones.
What do acrylic soft linings contain? Give a named example.
- 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.
What do silicone soft linings contain? Give a named example.
- 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.
What material are permanent relines usually made of? Where are they usually placed? (chairside vs lab).
- Heat cured acrylic.
- Lab.
4 indications for the use of permanent relines?
- 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).
What are the steps of a reline/ rebase technique?
- 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.
What materials can be used to take the wash impression for a rebase/ reline technique?
- Silicone impression material.
- Zinc oxide eugenol.