What are the disadvantages of restorations?
- May not make intimate contact with tooth surface (esp dentine)
- Exothermic reactions
- Chemicals released
What is the purpose for a cavity liner?
- Prevents microleakage
- Acts as protective barrier (chemical, thermal, bacterial)
- Therapeutic (calms inflammation)
- Palliative (calms symptoms until definitive tx)
What cavity liners/ bases are there?
- Setting CaOH = liner
- Zinc oxide based cements = base
- GI/ RMGIC = base or liner
- Palliative cements = base (seldom used)
What type of reaction is sCaOH?
Acid-base chelation
What is the mode of action of sCaOH?
- Bactericidal (pH12 kills acidic bac)
- Irritation –> releases Ca from pulp –> stimulates odontoblasts –> tertiary dentine formation
What are the advantages of sCaOH?
- Quick setting time
- Radiopaque
- Easy to use
What are the disadvantages of sCaOH?
- Low compressive strength
- Soluble –> unstable
- Does not bond to dentine
What types of zinc oxide based cements are there?
- Zinc phosphate
- Zinc polycarboxylate
- ZOE
- RMZOE
- EBA/ZOE
What are the clinical indications for ZOE?
- Lining/ base in deep cavities (Am only, discolours comp)
- Root canal sealer
- Periodontal dressing
- Temporary restorations (RM or EBA ZOE)
What type of reaction is ZOE?
Acid-base chelation
What are the advantages of ZOE?
- Good working time
- Good setting time
- Low thermal conductivity
- Radiopaque
- Soluble –> released eugenol reduces pulp pain
What are the disadvantages of ZOE?
- Weak
- High solubility
- Inhibits set of resin-based materials (softens and discolours)
What is the advantage of using EBA ZOE?
- Stronger than ZOE or RMZOE
- Less soluble
What is the advantages of GIC?
- Bonds and seals dentine
- F release
- Easy to use
- Low thermal conductivity
- Strong
- Radiopaque
- Low solubility
- Can bond to restorative materials
What are the disadvantages of RMGIC?
Requires curing, any unreacted HEMA may damage pulp
What lining material is recommended for cavities in dentine?
RMGIC (Vitrebond)
When is it recommended to use sCaOH?
Cavities close to pulp
Direct/ indirect pulp cap
