Complete Dentures - Copies and Relines/Rebases

Question 1

What are copy dentures?

Answer 1

Replicating a person’s previous set of dentures and incorporating everything good while adjusting slight problems.

Question 2

How are copy dentures made?

Answer 2

• Silicone putty mould made of denture.
• Material poured inside with relief holes.
• The denture will be wax teeth and acrylic base. Use as record rims in patients, use blue mousse and check occlusion.
• Send to the lab. They send a wax try-in which we carry out a wash impression of.
• Then we send it back and it’s converted to acrylic and we fit those in.

Question 3

What are the indications for copy dentures?

Answer 3

• Pt happy with their dentures they’ve worn for many years.
• Only a prev set that patient has been fine with.
• Older patients

Question 4

Contra-indications for copy dentures?

Answer 4

Major defects

Teeth not in neutral zone

Question 5

What are soft (resilient) linings?

Answer 5

Soft cushioning material placed on fitting surface of denture to reduce pressure points and improve comfort for patient.

Question 6

What are the indications?

Answer 6

• Sharp bony ridges
• Superficial mental nerve
• Atrophic mucosa
• Pain for no visible reason
• Previous good experience
• Obturator
• Around undercuts in tuberosity.

Question 7

What are the two types? Good and bad stuff about them?

Answer 7

Silicone and acrylic.

Silicone is good because it remains soft forever. But it is prone to candida and requires special burs to polish (otherwise looks rubbery) and needs glue to bond so can easily debond.
Needs 2mm thickness.

Acrylic is good because it chemically bonds to the denture base as it’s PMMA too, and it can be polished to look nice. But it’s more rigid and plasticiser is added but it leaches out, and can become rigid with cold drinks.

Both last around two years max.

Question 8

What are relines and how can they be done?

Answer 8

When the soft tissues underneath the denture change shape, it can affect retention so relines effectively fill the gap.

Can be done chair-side or laboratory using acrylic.

Chair-side problems:
- monomer irritant
- not as good full conversion of monomor to polymer
- post-dam destroyed which affects retention
- thickness of palate
- increased OVD.
+ immediate result with fewer stages

Lab uses a wash impression with silicone putty closed-mouth technique and then convert it to acrylic.
+ better conversion
- patient is without denture for a few days
- existing base material may warp if heat is used to polymerise the lining

Question 9

What is a rebase? What are its advantages?

Answer 9

This is the same technique but a wash material is taken of the denture and sent to the lab where the whole fitting surface is removed and a new one placed one which is made of acrylic.

It means there’s no increase in thickness or OVD and a new post-dam can be made.

Disadvantage: patient is without dentures for a few days.

Question 10

What are tissue conditioners and their uses?

Answer 10

Temporary (lasts about a week) cushioning material placed on inside of fitting surface. Helps to relieve patient from pain.

Uses:

• Pain e.g.. due to ulcers
• To see if soft linings are suitable for patient
• To wait while new dentures are being made.

Negatives:

• Plasticiser leaches out so softness goes
• Dislodges easily during cleaning
• Lasts 1-2 weeks.