Restorative Materials In Relation to Paediatric Dentistry Flashcards
Name some of the restorative materials that are used for paediatrics
- Amalgam
- Composites
- GICs
- RMGICs
- Compomers
- Preformed stainless steel crowns
What needs to be considered when choosing a restorative material for a child patient
- Clinical situation - National guidelines
- Tooth structure and cavity depth
- Longevity
- Toxicity
- Patient/child compliance - procedure length and moisture control
- Parents consent
What is the required retentive cavity depth for dental amalgams
2mm.
What are the benefits of choosing dental amalgams
- Good longevity
- Cost effective, economical, easy to use
- Excellent mechanical properties
- No shrinkage
- Not moisture sensitive (delayed expansion due to Zn presence)
What are the disadvantages of using composites
- Cured in 2mm increments
- Shrinkage/contraction on polymerisation
- Not natively adhered needs etching/bonding agent
What are the benefits of using composite filling materials
- Good creep resistance and compressive strength
- Excellent aesthetics
- Command set - light
What are some of the limitations of composites
- Adhesive first and then retenion
- Greater polymerisation shirnkage in large restorations
- Dentine bonding is weaker than bonding to an acid-etched enamel
- High wear in contact areas
- Thermal expansion coefficient (TEC) mismatch
- For posterior restorations permanent/primary have to be considered - wear resistance, water absorption, polymerisation shrinkage
- Not a complete polymerisation
- Potential leaching of toxic monomer (bisphenol A)
What causes GICs to release ions like Ca2+ and Al3+
When the glass reacts with polyacrylic acid it degrades and releases these
What is the reaction medium for the acid base reaction to make GICs
Water
What kind of bond do GICs make with enamel and dentin
Chemical - carboxyl groups bind to calcium in the tooth apatite
What are some benefits of using GICs
- Fluoride release
- No shrinkage, no exotherm
- Not toxic
- Ease of placement in bulk
- Ultra conservative restoration
- Aesthetic
What are the limitations of using GICs
- Low strength and high wear at early stages
- Need protection from dehydration
- Low Diametral tensile strength
- Low tensile strength - brittle
- Not able to withstand high tensile loads
- Restoration to be supported by tooth tissue
What setting reactions are involved in Resin-modified GICs
- Acid-base reaction = Glass + Polyacid
- Light-activated free radical polymerisation of methacrylate groups of the polymer (HEMA)
What are the advantages of RMGICs over GICs
- Command set
- Tougher
- Earyl strength
- Improved longevity
- Can set in the dark
What is a disadvantage of RMGICs
HEMA is cytotoxic
What filler is used in Compomers (PAMCs)
Ionomer glass
How are Compomers (PAMCs) set
Entirely by light
What are the advantages of compomers (PAMCs)
- Fluoride release
- Longevity
- Greater strength than GIC and RMGIC
What are the limitations of Compomers (PAMCs)
- Polymerisation shrinkage
- Exothermic reaction
- Bonding has to be done
What are PMCs/SSCs and where are the most often used
PMC = preformed metal crown
SSC = Stainless steel crowns
Extracoronal restoration for primary teeth.
What makes steel become stainless steel
The addition of chromium and nickel to the Iron and Carbon of steel
Why is stainless steel corrosion resistant
the chromium forms Cr2O3 at the surface