5 - Prosthetic Tooth Materials & Linings

Question 1

artificial teeth:
based on which material?
how does it develop resistance to crazing?
how is it connected to denture base resin?

Answer 1

• acrylic
• highly cross linked
• by a chemical bond

Question 2

acrylic based artificial teeth: name one advantage and disadvantage?

Answer 2

• easy to modify

- susceptible to wear

Question 3

materials for artificial teeth - porcelain based:

• how common?
• how is it attached to denture base resin?
• susceptible to?
• how easy to adjust?

Answer 3

• rarely used
• mechanically attached
• cracks around area of attachment
• difficult to adjust

Question 4

other materials used for artificial teeth?
examples where it is used?
advantage?

Answer 4

• composite resin based
• combination of materials
• used in dental implants
• less susceptible to wear

Question 5

permanent soft lining materials: clinical uses?

Answer 5

• atrophic ridge and mucosa (soft lining gives cushioning as ridge takes more force)
• undercut ridges (flexible flange)
• obturators (flexible bung)

Question 6

acrylic soft linings: 2 types?

Answer 6

heat cured

self cured

Question 7

heat cured acrylic soft lining: components?

Answer 7

• polyethylmethacrylate (polyme)
• butyl methacrylate
• butyl-phthalybutyl glycolate (plasticiser)

Question 8

advantages of acrylic soft lining materials?

disadvantage?

Answer 8

• good bonding between denture base and lining material

- material hardens over time because plasticiser leaches out

Question 9

silicone soft lining materials: 2 types?

Answer 9

heat cured

self cured

Question 10

silicone soft lining materials

Answer 10

• polydimethysiloxane (vinyl end groups)

- bonding agent required

Question 11

advantages of silicone based materials?

disadvantages?

Answer 11

• maintains softness
• failure of acrylic/silicone bond
• rough surface, difficult to modify
• lining material takes up stain
• susceptible to candida colonisation
• risk of denture fracture

Question 12

lab technique for acrylic/soft lining denture - how many stages?

Answer 12

two stage technique; acrylic curing first

Question 13

lab technique for acrylic/soft lining denture - spacer constructed for?

Answer 13

to prevent acrylic reaching area where soft lining will be placed

Question 14

lab technique for acrylic/soft lining denture: steps?

Answer 14

1. acrylic packed, flask closed, allowed to partially cure
2. spacer removed from model
3. adhesive applied to acrylic, molloplast packed

Question 15

permanent soft lining materials & cleaning dentures

• aggressive brushing will cause?
• if cleansers is used too hot what will happen?

Answer 15

• will cause disturbance in bond between acrylic and lining

- changes in surface roughness and colour

Question 16

temporary soft lining materials: components and its constituents?
what happens during setting? what properties does it have?

Answer 16

• powder: polyethyl methacrylate
• liquid: ethanol, plasticiser (flexibility)
• setting is formation of a gel, which has viscoelastic properties

Question 17

clinical uses of temporary soft lining materials?

Answer 17

• temporary relines (for dentures undergoing modification, transition phase after implant placement)
• tissue conditioner (used in ill fitting dentures to allow recovery of inflamed tissues in denture bearing area)
• functional impressions (rebasing denture, modify fitting surface of obturator, recording neutral zone)

Question 18

functional impression for rebasing: steps?

Answer 18

• use coe-comfort in denture base
• pt wears denture for few fats
• records impression of tissues during function
• used for rebase impression

Question 19

temporary soft lining materials and cleaning dentures:

• brushing lining will cause?
• what happens if cleanser used is too hot?

Answer 19

• deterioration

- changes in surface roughness and colour