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Direct Polymeric Restorative Materials DHYG 113 Restorative Dentistry I.

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Presentation on theme: "Direct Polymeric Restorative Materials DHYG 113 Restorative Dentistry I."— Presentation transcript:

1 Direct Polymeric Restorative Materials DHYG 113 Restorative Dentistry I

2 Objectives Discuss properties of restorative resins: polymerization shrinkage, coefficient of thermal expansion, and abrasion resistance Discuss properties of restorative resins: polymerization shrinkage, coefficient of thermal expansion, and abrasion resistance Summarize filler particle, matrix, and the coupling agent of a composite restorative material Summarize filler particle, matrix, and the coupling agent of a composite restorative material Explain proper eye protection when using light-cured materials Explain proper eye protection when using light-cured materials Explain the meaning of ‘addition’ in addition polymerization Explain the meaning of ‘addition’ in addition polymerization Describe : depth of cure, addition of material in increments, inhibition by air, unreacted C=C bonds, shades, shortcomings of the matrix Describe : depth of cure, addition of material in increments, inhibition by air, unreacted C=C bonds, shades, shortcomings of the matrix Explain the fillers found in dental composites: composition, size, amount, abrasion resistance, refractive index, clinical detection Explain the fillers found in dental composites: composition, size, amount, abrasion resistance, refractive index, clinical detection

3 Explain the difference between flowable and condensable composites Explain the difference between flowable and condensable composites Discuss the role of the dental hygienist in the placement and maintenance of pit and fissure sealants Discuss the role of the dental hygienist in the placement and maintenance of pit and fissure sealants Discuss the use of a primer with pit and fissure sealants Discuss the use of a primer with pit and fissure sealants Describe preventive resin restoration and composite cements Describe preventive resin restoration and composite cements Assess the positive and negative characteristics of light- cure and chemical-cure glass ionomer cements Assess the positive and negative characteristics of light- cure and chemical-cure glass ionomer cements Discuss similarities between compomers, glass ionomers, and composites Discuss similarities between compomers, glass ionomers, and composites

4 Monomers Functional group participates in polymerization (chemical) reaction Functional group participates in polymerization (chemical) reaction Carbon-Carbon double bond (C=C) Carbon-Carbon double bond (C=C) Free Radical – unpaired electron Free Radical – unpaired electron Addition polymerization – one monomer at a time is added to the chain Addition polymerization – one monomer at a time is added to the chain Initiation – first step (formation of free radical) Initiation – first step (formation of free radical) Heat activated-- Light activated Heat activated-- Light activated Chemically activated-- Dual cure materials Chemically activated-- Dual cure materials

5 Resin Shrinkage

6 Propagation Propagation Second step in addition polymerization Second step in addition polymerization Termination Termination Free radicals at ends of chain react (stops process) Free radicals at ends of chain react (stops process) Exothermic reaction Exothermic reaction Releases heat Releases heat Thermoplastic – can be heated and shaped Thermoplastic – can be heated and shaped Thermoset polymers – most dental resins Thermoset polymers – most dental resins

7 Working Time Polymerization can happen quickly Polymerization can happen quickly Reaction must occur when desired Reaction must occur when desired Light cured material Light cured material Delayed with inhibitor for chemical-cured Delayed with inhibitor for chemical-cured Hydroquinone (ex.) destroys first free radicals Hydroquinone (ex.) destroys first free radicals Without delay, the material would set up too fast Without delay, the material would set up too fast

8 Shelf Life Liquid components of acrylic resins are almost entirely monomers Liquid components of acrylic resins are almost entirely monomers Free radical could polymerize entire container Free radical could polymerize entire container Manufacturers add inhibitor to monomer materials to prevent them from becoming a solid mass Manufacturers add inhibitor to monomer materials to prevent them from becoming a solid mass

9 Problems with Resins Polymerization shrinkage Polymerization shrinkage Coefficient of Thermal Expansion Coefficient of Thermal Expansion High (can be 2-10 times greater than tooth) High (can be 2-10 times greater than tooth) Problem with percolation Problem with percolation Lack strength & abrasion resistance

10 De-bonding Once desiccated, the de- bonding becomes very apparent Bouschlicher,Vargas,Boyer.Effect of composite type, light intensity,configuration factor and laser polymerisation on polymerisation contraction forces. Am J Dent 1997 Apr,10(2)88-96 Bouschlicher,Vargas,Boyer. Effect of composite type, light intensity,configuration factor and laser polymerisation on polymerisation contraction forces. Am J Dent 1997 Apr,10(2)88-96

11 Color Hue – dominant color of the object Hue – dominant color of the object Red, blue, yellow (teeth are yellow to yellow-red) Red, blue, yellow (teeth are yellow to yellow-red) Value – refers to lightness of a color Value – refers to lightness of a color Scale of 1 – 10 ( 1=black, 10=white) Scale of 1 – 10 ( 1=black, 10=white) Chroma – refers to intensity of color Chroma – refers to intensity of color Scale of 1 – 10 (rich or pale) Scale of 1 – 10 (rich or pale)

12 Appearance Translucency – enamel at incisal edges Translucency – enamel at incisal edges Opacity – dentin affects light passing through Opacity – dentin affects light passing through Gingiva affects color at margin Gingiva affects color at margin Rubber dam Rubber dam Match shade before placing to get best results Match shade before placing to get best results

13 Composites Dr. Raphael Bowen, 1960’s Dr. Raphael Bowen, 1960’s Fillers and Silane Coupling Agents Fillers and Silane Coupling Agents Industrial: fiberglass Industrial: fiberglass Fillers typically ceramic (silica) particles Fillers typically ceramic (silica) particles Silane Coupling agents: work like soap to react with silicon and oxygen on the surface of the ceramic filler Silane Coupling agents: work like soap to react with silicon and oxygen on the surface of the ceramic filler Composite strength increases, polymerization shrinkage decreases, limits thermal expansion Composite strength increases, polymerization shrinkage decreases, limits thermal expansion

14 Composite Components Matrix Matrix Monomer Monomer Diluent – added to control viscosity Diluent – added to control viscosity Polymerizes by Addition Polymerization Polymerizes by Addition Polymerization Chemical cure – two paste system Chemical cure – two paste system Light cure – single paste material Light cure – single paste material

15 Composite Polymer Dr. Bowen developed – for dental composites Dr. Bowen developed – for dental composites Combination of several monomers Combination of several monomers Oligomer: Bifunctional since each C=C group can participate in formation of growing chain Oligomer: Bifunctional since each C=C group can participate in formation of growing chain Cross-linking = improved strength Cross-linking = improved strength Bis-GMA Bis-GMA Methyl methacrolate (most common) Methyl methacrolate (most common) Triethelene glycol dimethacrylate Triethelene glycol dimethacrylate

16 Fillers Originally quartz materials (sand) Originally quartz materials (sand) Engineered glass materials Engineered glass materials Size determines surface smoothness Size determines surface smoothness Macrofill – largest size particles, rough texture Macrofill – largest size particles, rough texture Microfill – 1970’s, polish smooth, appear similar to enamel, useful for Class III & V restorations due to modulus of elasticity Microfill – 1970’s, polish smooth, appear similar to enamel, useful for Class III & V restorations due to modulus of elasticity Small particle – 1980’s, 80-85% filled Small particle – 1980’s, 80-85% filled Hybrid – late 1980’s, strong & abrasion resistant (Class I & III) Hybrid – late 1980’s, strong & abrasion resistant (Class I & III)

17 Conventional Quartz or Glass Average = 20 Range = AdapticConciseProfile Microfill Fumed Silica PPRF Average =.04 Range = Silar/SiluxDurafillHelioprogress Small hybrid Quartz or glass Average = Range = Herculite XR Z100, Z250 Tetric Ceram Midsized hybrid Quartz or glass Fumed silica Average = Range = Average = Bisfil-POcclusinClearfilP-50 CompositeClass Filler Type Filler Size ( µ m ) Filler Volume (%)Examples

18 Composite restorations Composite restorations Composite restorations are shown in centric occlusion from the lingual aspect on the laboratory models. Laboratory models

19 Flowable Composites Class V restorations Micro preparations Extended fissure sealing Adhesive cementation of ceramic restorations Blocking out cavity undercuts Initial (base) layer in any classification Resin coating technique

20 Self-Curing & Light Curing Resins Self-CuringLight-Curing Paste A Paste B Paste MonomersInitiatorMonomersActivatorMonomersInitiatorAccelerator Mixing A and B, or light curing the paste causes: Initiator + activator (acclerator) reactive initiator Reactive initiator + monomers reactive monomers Reactive monomers + monomers polymers

21 Adhesives Dentin bonding systems Dentin bonding systems Scotch Bond Multi Purpose Scotch Bond Multi Purpose EBS-Multi EBS-Multi solvent-free adhesive system for the "Total-Etch" technique solvent-free adhesive system for the "Total-Etch" technique

22 Depth of Cure The thickness of composite cured by typical light source The thickness of composite cured by typical light source Penetration of curing light – only several mm Penetration of curing light – only several mm Depends on time of light exposure, product, shade, and the light Depends on time of light exposure, product, shade, and the light If material nearest to pulp is not cured, can result in sensitivity If material nearest to pulp is not cured, can result in sensitivity Composites placed in layers to prevent uncured material Composites placed in layers to prevent uncured material

23 Incremental Addition Placing composites in layers: Placing composites in layers: Assures polymerization Assures polymerization Allows for shrinkage (normally about 2%) Allows for shrinkage (normally about 2%)

24 Condensable Composites Filler particle inhibits sliding of filler particles by one another Filler particle inhibits sliding of filler particles by one another Results in “thicker, stiffer feel” Results in “thicker, stiffer feel”

25 Placement of Composite Restoration 1. Diagnose lesion 2. Determine shade needed 3. Isolate area 4. Cut cavity preparation 5. Place cavity liner if necessary 6. Etch, prime, and place adhesive 7. Place composite incrementally; cure 8. Finish

26 9. Check proximal contacts 10. Examine for voids and marginal defects 11. Polish 12. Remove rubber dam 13. Check occlusion

27 Sealant & Preventive Resins Sealants reduce caries in pits and fissures Sealants reduce caries in pits and fissures Etch, then bond (light or chemical cured) Etch, then bond (light or chemical cured) Preventive resins: combination of sealant and composite restoration Preventive resins: combination of sealant and composite restoration Suspicious pit is opened with a bur or air abrasion Suspicious pit is opened with a bur or air abrasion Tooth is etched, primed, and adhesive placed Tooth is etched, primed, and adhesive placed Prepared pit is filled with hybrid composite Prepared pit is filled with hybrid composite Other pits and fissures filled with sealant Other pits and fissures filled with sealant Conservative – not a Class I preparation Conservative – not a Class I preparation

28 Glass Ionomer Chemical cure – first adhesive restorative material Chemical cure – first adhesive restorative material Light-cure, late 1980’s Light-cure, late 1980’s Powder-liquid systems (acid-base setting reaction) Powder-liquid systems (acid-base setting reaction) Placed directly into cavity preparation Placed directly into cavity preparation Advantages: Advantages: Fluoride releasing – good for high caries risk, Class V Fluoride releasing – good for high caries risk, Class V Adhesive Adhesive Luting cements Luting cements

29 Glass-ionomers Postoperative Sensitivity Reduced or Eliminated Chemically and Mechanically Bonds to Tooth Structure Flexes with Tooth, Cushions Occlusal Forces Outstanding Fluoride Release Protects restoration from secondary decay Consistent results, Easy to Use ShrinkageExpansion Masticatory pressure Secondary caries

30 Compomers Combination of Glass Ionomer and Composite/Dentinal bonding materials Combination of Glass Ionomer and Composite/Dentinal bonding materials Bond and set like composites Bond and set like composites Release fluoride like glass ionomers Release fluoride like glass ionomers Example: Example: 3M F2000 tooth structure both react to temperature changes to the same degree and shows an elasticity comparable to microfill restoratives (following slides from 3M conference in South Africa)

31 Compomers "Dyract ® AP cavities etch adhesive compomer placedsetting

32 Class V Compomer Figure 1 - Class V defect in lower right central incisor. Incisal enamel abrasion points to abfraction as possible contributing cause.

33 Figure 2 - After cleaning, shade taking and preparation, the compomer primer is directly dispensed from the 3M Clicker system into the mixing well. Figure 2 - After cleaning, shade taking and preparation, the compomer primer is directly dispensed from the 3M Clicker system into the mixing well.

34 Figure 3 - After shortly mixing the liquids in the well with a brush, the same brush is used to apply the primer to the entire cavity. Figure 3 - After shortly mixing the liquids in the well with a brush, the same brush is used to apply the primer to the entire cavity.

35 Figure 4 - After 30 seconds the primer is gently air dried for 5-10 seconds Figure 4 - After 30 seconds the primer is gently air dried for 5-10 seconds

36 Figure 5 - The primer Figure 5 - The primer is light cured for 10 seconds is light cured for 10 seconds

37 Figure 6 - After light curing the primer, the compomer can be applied. Capsules are preferred because the material can be applied directly into the cavity Figure 6 - After light curing the primer, the compomer can be applied. Capsules are preferred because the material can be applied directly into the cavity

38 Figure 7 - A preformed matrix is put on the restorative prior to a 40 seconds light cure to facilitate contouring and finishing of the restoration. Figure 7 - A preformed matrix is put on the restorative prior to a 40 seconds light cure to facilitate contouring and finishing of the restoration.

39 Figure 8 - After the use of Sof-Lex finishing and polishing discs the end result shows a good color match and marginal adaptation. Figure 8 - After the use of Sof-Lex finishing and polishing discs the end result shows a good color match and marginal adaptation.


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