Dental Composite PropertiesAnd

Shrink – Free Composite

Done by : Ghadeer suwaimiLFatimah al-marhoon

Outline

-Dental Composite And Its Properties.

-Advantage And Disadvantage Of Dental Composite.

-Polymerization Shrinkage .-Low Shrinkage Composite.

-Advantage Of Low Shrinkage Composite .

Dental composite

Resin

Unfilled Resin

Composite

:Definition

Mixture Of Two Or More Components.

Dental composite

Major components

Organic resin

matrixPolymer

filler materials

-Increase the strength and mechanical properties.

Coupling agent

to improve adherence of resin

to filler surfaces.

Activation systems

including heat, chemical and

photochemical initiate

polymerization. 

Plasticizers

solvents that contain catalysts for mixture into

resin

 Physical characteristics improve by combining more than one type of monomer and are referred to as a copolymer

Thermal conductivity: composite restoration has a lower thermal conductivity than do metallic restorations such as gold alloy or amalgam--silver-colored restorations.Water sorption : less than the unfilled resin.Water solubility : has lower solubility than unfilled resin.

Properties of CompositesPhysical Propertie

Color : Tooth-colored fillings that are designed to match the color of your teeth

Adhesion : can be bonded directly to a tooth's surface . How ?

Coffecient of thermal : composites have a higher thermal expansion than tooth structure does, which means composites easily can change dimensions as temperature changes in the mouth.

Properties of Composites

Mechanical Propertie Tensile : Composites Require Strong Tooth Structure To Support The Filling Because The Tensile And Shear Strength Is Low

Durability:Composite Restorations Are Not As Durable As Other Materials. Composite Fillings Previously Were Not As Durable As Amalgams.

Properties of Composites

Compressive Stength : highModulus Of Elasticity : high

1)Composite resin has less irritant effect on pulp and on the soft tissue in oral cavity.

2)Polymerization shrinkage

Biological Propertie

Properties of Composites

1 .  Tooth Colored Appearance Of Composites Is More Cosmetically Appealing Than Dental Amalgam.

2   .A Composite Dental Composite Filling Will Often Be Smaller In Size Than A Comparable Silver  Amalgam Filling

3 .  Tooth Bonding Usually Creates Less Post Treatment Thermal Sensitivity.

4   .Dental Composite Fillings Are Ready To Be Used Immediately After The Dental Appointment Has Been Completed.

    

Advantage of composite

Advantage of composite

5   .These fillings cause no galvanic reactions.

6  .Direct composite fillings are placed in one appointment only.

7   .These can be easily repaired.8   .Bonded resins may enhance tooth

strength.9  .Some materials release fluoride.

10  .Available in variety of shades so that filling can match the shade of tooth  .

    

-Lacks self sealing ability, unlike amalgam.-Leakage occurs with a high rate of

secondary caries because of the breakage of adhesive tooth bond.

-Composite filling usually cost more than amalgam .

- It takes more time for a dentist to place a bonded restoration  These fillings discolor over time.

Disadvantage of composite

Disadvantage of composite

-Excessive wear under stress.-Low fracture strength.

-High technique sensitivity as the tooth must be adequately isolated when a dental composite is placed

-Generation and inhalation of dust during finishing procedures present potential hazards for patient and the staff .

Polymerization shrinkage-An Intrinsic Property Of

Resin. -Upon Curing, The Single Methacrylate Resin Molecules Move Towards Each Other And Are Linked By Chemical Bonds To Form A Polymer Network. This Reaction Leads To A Significant Volume Contraction.

Configuration Factor (C-factor)

is the relation between the number of surfaces bonded divided by the number of surfaces unbonded.As the configuration factor goes up, the effects of polymerization stress and strain become more significant in maintaining marginal seal.

Polymerization shrinkage

Low shrinkage composite

System Has Been Developed ToMinimize Polymerization Shrinkage

AndPolymerization Stress, While

Providing A High performance Bond To The Tooth.

For example

Silorane Ormocer

Low shrinkage composite

-As Silorane-based Composite Polymerizes, “Ring Opening” Monomers Connect By Opening,flattening And Extending Towards Each Other. The Result Is Significantly Less Volumetric Shrinkage Compared To Methacrylate-based Composites. -As Methacrylate-based Composites Cure, The Molecules Of These “Linear Monomers” Connect By Actually Shifting Closer Together In A Linear Response. The Result Is A Loss Of Volume.

1 ) Silorane

Chemistry of silorane

SILORANE

METHACRYLATE

Chemistry of silorane

The Name Silorane Derives From Its Chemical Building Blocks Siloxanes And Oxiranes. The Combination Of The Two Chemical Building Blocks Of Siloxanes And Oxiranes Provides The Biocompatible,hydrophobic And Low-shrinking Silorane Base Of Filtek LS Low Shrink Posterior Restorative.

Chemistry of silorane

Initiator system

This consists of camphorquinone,

iodonium salts & electron donors and reactive

cationic species.

Filler component

This consists of fine quartz particles and radiopaque yttrium

fluoride.

Adhesive system

Two-step AdhesiveSelf-etch Primer :

Hydrophilic Helps In Adhesion To The ToothBond : HydrophobicHelps In Adhesion To Silorane System

1 )The first composite to shrink less than 1%

2 )Strong and durable3 )Low water sorption leading to

decreasedexogenic staining

4 )Radiopaque5 )Up to 9 minutes operatory light

stability

Advantage of low shrinkage composite

Advantage of low shrinkage composite

6 )Easy To Handle, Nonsticky & Excellent Ability To Hold Shape.

7 )Dedicated Self-etch AdhesiveWith Excellent Bond Strength.

8 )Excellent Marginal Integrity.

Ormocer Materials Contain Inorganic-organic Copolymers In Addition To The Inorganic

Silanated Filler Particles. It Is Synthesized Through A Solution And Gelation Processes

(Sol-gel Process) From Multifunctional Urethane And Thioether(meth)acrylate Alkoxysilanes. Ormocers Are Described As 3-dimensionally Cross-linked Copolymers. The filler material

consists of a special glass ceramic and highly disperse

.silica

2 ) Ormocer

Ormocer Was Formulated In An Attempt To Overcome The Problems Created By

The Polymerization Shrinkage Of Conventional Composites Because The

Coefficient Of Thermal Expansion Is Very Similar To Natural Tooth Structure

2 ) Ormocer

Any Questions?

http://www.biomedsearch.com/article/Dental-ceramics-ormocer-technology-navigating/165363951.html

http://www.sciencedirect.com/science/article/pii/S0300571208002303

http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2842.2010.02066.x/abstract

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3442430/

http://www.sso.ch/doc/doc_download.cfm?uuid=BC57B04E903739FBB9D6BA480B2D2018

http://digitalcollections.lrc.usuhs.mil/cdm/compoundobject/collection/p15459coll1/id/104179/rec/4

http://www.oralhealthgroup.com/news/the-search-for-a-low-shrinkage-direct-composite/1000364318/

http://www.kssfp.jp/pdf/APJD11-1Tanno27-33.pdf

http://www.dentalaegis.com/id/2009/03/manufacturers-introduce-new-composite-formulations-being-advertised-as-low-shrink-composites

http://multimedia.3m.com/mws/mediawebserver?6666660Zjcf6lVs6EVs66sz6jCOrrrrQ-http://www.dypdentaljournals.com/2008/Dr.%20Prachi%20Joshi%20-%20conso.pdf

References