Restorative Materials In Paediatric Dentistry Flashcards
Name some restoratives for paediatrics (6)
- Amalgam
- Composites
- Glass ionomer cements
- Resin modified GIC
- Compomers
- Preformed stainless steel crowns
What are some factors to consider for choice of restorative material for child patient (6)
- Clinical situation
- Tooth structure
- Longevity
- Toxicity
- Child compliance
- Parents consent
Give some advantages of dental amalgams (6)
- Good longevity
- Cost effective
- Easy to use
- Excellent mechanical properties
- No shrinkage
- Not moisture sensitive
What is the minimum depth required of a cavity for a dental amalgam?
2mm min depth
What is the age limitation of amalgams?
Not used for under 15 year olds
Give some advantages of composites (3)
- Good creep resistance
- Good compressive strength
- Excellent aesthetics
What are some limitations of composites? (5)
- Good adhesive bond has to be established
- Polymerisation shrinkage
- Dentine bonding is weaker that enamel
- High wear in contact areas
- Mismatch in thermal expansion coefficient
How is shrinkage reduced in composites?
Incremental filling
What ions are released by GIC? (2)
- Ca2+
- Al3+
Give some advantages of GIC (6)
- Chemical bond to enamel and dentine
- Carboxyl group binds to calcium in tooth apatite
- Fluoride release / uptake
- No shrinkage
- Ease of placement in bulk
- Aesthetic
Give some limitations of GIC (4)
- Low strength
- High wear at early stages
- Need protection from dehydration
- Restoration to be supported by tooth tissue
Are resin modified GIC water or acid based?
Water based
For resin modified GIC what acid base setting reaction takes place?
Glass + Polyacid
For RMGIC besides the acid base setting reaction what other setting reaction takes place?
Light-activated free radical polymerisation of methacrylate groups of the polymer (HEMA)
How is RMGIC more advantageous than conventional GIC? (3)
- Command set tougher
- Early strength
- Improved longevity
Give some key features of Polyacid-modified composite resin compomers (4)
- Fluoride release delayed
- Longevity
- Greater strength than RMGIC and GIC
- Coloured restorations
What are Preformed metal crowns (PMC) or Stainless steel crowns (SSC)?
Extracoronal restoration for primary teeth
What is PMC/SCC made of? (4)
Iron and Carbon alloy with the addition of Chromium and Nickel
What makes PMC/SCC corrosion resistant?
- Resistant to corrosion due to Chromium
- Cr2O3 forms at the surface
What % composition of Cr is needed to make the steel corrosion resistant?
Cr>11%
Give some advantages of SSC/PMC (5)
- High tensile strength
- Durable
- Preventative
- Cost effective
- Prefabricated sizes
Give some limitations of SSC/PMC (3)
- Bad aesthetics
- Complex procedure
- Ni/Cr could be allergens
Give examples of some preventative materials (4)
- Toothpaste
- Mouthwash
- Topical fluoride
- Sealants
How is fluoride beneficial for teeth?
- Fluoride substitutes for hydroxyl in apatite
- Makes enamel chemically stronger and more acid resistant
- Reduces plaque activity
Comment on the thixotropic property of fluoride gels
- Fluoride gel become viscous when pressure is applied (when mouth guard is squeezed around tooth)
- This allows the gel to flow around tooth surfaces
- Once pressure is removed it sticks to the tooth
Give some examples of fluoride gels (3)
- Sodium fluoride (NaF)
- Stannous fluoride (SnF2)
- Acidulated Phosphate Fluoride (APF)
What is the pH of APF?
pH 3
What happens when fluoride varnish is applied to the teeth?
What is produced?
- Solvent evaporates or sets in moist conditions
- A lot of CaF2 is produced
What are pit and fissure sealants?
- Sealants used on primary and secondary teeth
- Reduces carries
- Aids in fluoride release
What can pit and fissure sealants be based off? (4)
- Resin based
- GIC based
- RMGIC based
- Compomer based
Comment on the properties of pit and fissure sealants (4)
- High coefficient of penetration
- High surface tension
- Low viscosity
- Good wetting
What is added to BisGMA-based resin sealants to reduce it viscosity? (2)
Why is this done?
- MMA or TEGDMA
- To make sealant more penetrable
How are UDMA based resin sealants cured? (3)
- Light-cured
- Self-cured
- Chemically cured
What initiates polymerisation in a Cyanoacrylate-based resin sealant?
Polymerisation is initiated by water
Cyanoacrylate-based resin sealant;
2 advantages
2 disadvantages
- Low viscosity
- Good penetration
- Low tensile strength
- Low abrasion resistance
