Direct Esthetic Direct Esthetic Restorative MaterialsRestorative Materials

Both silicate cement and acrylic resin (PMMA) are Materials from History

Science of Science of Resin Resin

CompositesCompositesFor Direct RestorationsFor Direct Restorations

• Materials made up of 2 /+ distinct, chemically different phases

• The resulted material (composite) combine the properties of the phases included

Examples • Jell-o & fruits• Concrete• Tooth enamel and

dentine• Resin composite

Composite !!! What does it mean?

Dental Resin Composites

Matrix phase

Dispersed phase(fillers)

1. Organic phase (matrix)2. Inorganic dispersed

phase (fillers)3. Coupling phase

1. Polymerization-associated additives

2. Coloring additive3. Ultraviolet stabilizers4. Radioopacifiers

+

Coupling phase

Organic Phase (Resin Matrix )

Function

1. Hold all ingredients in one mass

2. Able to polymerize (Responsible for material’s setting )

3. Accept pigments (Responsible for material’s color )

4. Responsible for the setting contraction

1. Monomer system

- BIS-GMA or UDMA. (viscous monomers)

- Silorane resins (in the most recent, minimal-shrink type)

2. Diluents

- TEGDMA & HEMA

Dispersed Phase (Fillers )

Function1. Mechanical Prop.

2. Wear resistance

3. Coeff. of th. Exp.

4. Poly. shrinkage

1. Inorganic fillers 1. Inorganic fillers - Quartz, glass, barium and lithium - Quartz, glass, barium and lithium

alumino-silicates, barium fluoridealumino-silicates, barium fluoride

- Zinc (Zn), Boron (B), zirconium (Zr) - Zinc (Zn), Boron (B), zirconium (Zr) and yttrium (Y) ions and yttrium (Y) ions are added to are added to produce radioopacityproduce radioopacity

2. Pre-polymerized organic fillers2. Pre-polymerized organic fillers - Ground resin composites- Ground resin composites

3. Alternative fillers 3. Alternative fillers - fibers, tri-modal, non-slumping fillers, - fibers, tri-modal, non-slumping fillers,

fluoride-releasing – Nano-sized fluoride-releasing – Nano-sized fillersfillers

Classification based on filler size and loadingTypes Filler size Filler load

Traditional types

1. Macro-filled 8-12 µm 75-80 wt%

2. Small particle 1-8 µm 70-85 wt%

3. Hybrid 0.4-1 µm 70-75 wt%

4. Micro-filled 0.04-0.4 µm 50-60 wt%

Recent types

5. Nano-hybrid 0.02-2.5 (Av 0.6) µm 70-75 wt%

6. Nano-filled Culsters- 0.06-1.4 µm (5-20 nm)

70-75 wt%

Macro-filled Small-particle Hybrid Micro-filled

Anusavice K. Phillip’s Science of Dental Materials 2003

Property Traditional Microfilled Small P. Hybrid

Compr. strength (MPa) 250-300 250-300 350-400 300-350

Tensile strength (MPa) 50-65 30-50 75-90 70-90

Elastic Modulus (GPa) 8-15 3-6 15-20 7-12

Coeff .Th. Exp. (10-6/ºC) 25-35 50-60 19-26 30-40

Knoop Hardness 55 5-30 50-60 50-60

Properties of traditional Composites

Quoted from: Deliperi S, Bardwell d. J Am Dent Assoc. 2002; 133:1387-1398

Quoted from: Deliperi S, Bardwell d. J Am Dent Assoc. 2002; 133:1387-1398

Coupling Phase

1.1. Vinyl triethoxy silane (vinyl silane)Vinyl triethoxy silane (vinyl silane)

2.2. γγ--Methacryloxy propyl trimethoxy SilaneMethacryloxy propyl trimethoxy Silane

Mechanism of attachmentMechanism of attachment

-- They are composed of They are composed of bi-functional moleculesbi-functional molecules

- The - The silane groupsilane group chemically bonds to the inorganic chemically bonds to the inorganic materialsmaterials

- Both the - Both the ethoxy and methoxyethoxy and methoxy groups groups react with resin react with resin molecules of the matrixmolecules of the matrix

FunctionFunction

1.1. The water uptakeThe water uptake

2.2. The solubility rateThe solubility rate

3.3. The crack propagationThe crack propagation

Bonding of fillers to resin matrix

Polymerization associated additives

Polymerization initiator….Polymerization initiator…...1.1. Benzoyl proxideBenzoyl proxide in case of chemical and heat- in case of chemical and heat-

cured materialscured materials

2.2. CamphroquinonCamphroquinon in case of light-cured materials in case of light-cured materials

Polymerization activator…Polymerization activator…Tertiary amineTertiary amine in in case of chemically-cured materialscase of chemically-cured materials

Polymerization inhibitor… Polymerization inhibitor… (hydroquinon)(hydroquinon) prevents material’s polymerization on storageprevents material’s polymerization on storage

Chemically-Cured CompositeChemically-Cured Composite

Light-cured compositeLight-cured composite

Effect of classical curing techniques on composite properties

Difference Chemical-cured (CC) Light-cured (VLC) Heat-Cured (HC)

• Presentation forms 2 paste (Base & Catalyst)

Single paste (Syringe, capsules)

- 1 paste- Powder and liquid

• Mixing Mixing of equal parts of base and catalyst over paper pad by the use of plastic spatula

No mixing is required (only direct dispensing from either the syringe or capsules)

Mixing of P&L form only

• Setting reaction Addition polymerization Addition polymerization Addition polymerization

• Polymerization initiator

Benzoyl peroxide Camphroquinon Benzoyl peroxide

• Polymerization activator

- 3ry amine (old)- N-dihydroxy ethyl–P-

toluidine

UV light, Blue VL, or Laser

Heat, or Heat&pressure

• Method of application

Direct, using bulk technique

Direct, using incremental technique

Indirect (Laboratory processed)

Property Chemical-cured (CC) Light-cured (VLC) Heat-Cured (HC)

• Working time - Limited- The chemical reaction starts once base and catalyst are mixed

- Unlimited- The chemical reaction starts when the material is subjected to light

- Unlimited- The chemical reaction starts when the material is subjected to heat

• Degree of polymerization

Higher than VLC and lower than HC

The lowest The highest

• Residual Monomer• (act as plasticizer)

Lower than VLC and higher than HC

The highest The lowest

• Polymerization shrinkage

Higher than VLC and lower than HC

The lowest The highest

• Strength and hardness

Higher than VLC and lower than HC

The lowest The highest

• Porosity Voids could exist as a result of air trapping during mixing

Less Than CC (No Mixing)

Less than CC (Depending on the packing technique)

• Color stability The lowest, due to presence of 3ry amine and porosities

Higher than CC and lower than HC

The highest

• Bonding to resin bonding agents

Lower than VLC and Higher than HC

The highest The lowest

• UV stabilizers… UV stabilizers… ((2-hydroxy-4- methoxy 2-hydroxy-4- methoxy benzophenone) benzophenone) Provide color stability under Provide color stability under electro-magnetic waveselectro-magnetic waves

• Coloring agents (Pigments)….Coloring agents (Pigments)…. To To provide materials with different shadesprovide materials with different shades

Other Additives

Listen, always keep these

Clinical Hints in your mind

Composite polymerization is retarded in presence of

Eugenol and oxygen.

It is mandatory to incrementally insert the light-cured material

The chemically-cured materials is no longer be used clinically

Mechanical, Micro-mechanical and inter-penetration means help the composite retain to the tooth structure

Direct applications of resin composites Filling class III, IV, V and VI cavities in anterior teeth Filling small and moderate Class I, II, V cavities in post. teeth Core build-up (strengthening of weakened teeth) Diastma Closure Direct laminate veneer

1. Esthetic.

2. Conservative cavity.

3. Low thermal conductivity.

4. Quite resistance to microleakage

5. No corrosion.

6. Strengthening of the remaining tooth st.

1. Polymerization shrinkage.

2. High coefficient of thermal expansion

3. Pulp irritation due to residual monomer ……i.e. deep cavities should be protected

4. Low wear resistance.

5. Technique sensitive.

Advantages

Disadvantages

Step By Step Restoration

Done

What do you exactly know about

the modified types of composite restoratives ?