Dental composite and shrink free composite

NOTE : all this from my reading in some scientific website and articles

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1. Dental Composite Properties And Shrink – Free Composite Done by : Ghadeer suwaimiL Fatimah al-marhoon

2. Outline -Dental Composite And Its Properties . -Advantage And Disadvantage Of Dental Composite. -Polymerization Shrinkage. -Low Shrinkage Composite. -Advantage Of Low Shrinkage Composite.

3. Dental composite

4. : Definition Mixture Of Two Or More Components. Dental composite

5.   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 Composites Physical Propertie

6. 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

7. 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 : high Modulus Of Elasticity : high

8. Composite resin has less irritant effect on pulp and on the soft tissue in oral cavity. 2)Polymerization shrinkage Biological Propertie Properties of Composites

9. 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

10. 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.       

11. -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

12. 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. 

13. Poly merization 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.

14. 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 .

15. Poly merization shrinkage

16. Low shrinkage composite System Has Been Developed To Minimize Polymerization Shrinkage And Polymerization Stress, While Providing A High performance Bond To The Tooth.

17. For example Silorane Ormocer Low shrinkage composite

18. -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

19. Chemistry of silorane SILORANE

20. METHACRYLATE Chemistry of silorane

21. 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

22. Initiator system This consists of camphorquinone , iodonium salts & electron donors and reactive cationic species.

23. Filler component This consists of fine quartz particles and radiopaque yttrium fluoride.

24. Adhesive system Two-step Adhesive Self-etch Primer : Hydrophilic Helps In Adhesion To The Tooth Bond : Hydrophobic Helps In Adhesion To Silorane System

25. 1) The first composite to shrink less than 1% 2) Strong and durable 3) Low water sorption leading to decreased exogenic staining 4) Radiopaque 5) Up to 9 minutes operatory light stability Advantage of low shrinkage composite

26. Advantage of low shrinkage composite 6) Easy To Handle, Nonsticky & Excellent Ability To Hold Shape. 7) Dedicated Self-etch Adhesive With Excellent Bond Strength. 8) Excellent Marginal Integrity.

27. 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

28. 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

29. Any Questions?

30. 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