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 Also known as Tooth colored materials, used in the restoration of natural teeth. used in the restoration of natural teeth.

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Presentation on theme: " Also known as Tooth colored materials, used in the restoration of natural teeth. used in the restoration of natural teeth."— Presentation transcript:

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2  Also known as Tooth colored materials, used in the restoration of natural teeth. used in the restoration of natural teeth.

3 Cast gold & gold foil restorations were the earliest.  Silicate cements  Glass Ionomer cements  Unfilled resins  Composite resins  Porcelain (veneers, crowns)  Porcelain bonded to metal crowns Restorative Resins TOOTH COLORED RESTORATIVE MATERIALS

4 RESTORATIVE RESINS ::  These are synthetic resins, evolved as restorative materials principally because restorative materials principally because of their Esthetic Characteristics. of their Esthetic Characteristics. TYPES – Unfilled = e.g. Acrylic Resins Unfilled = e.g. Acrylic Resins Filled = e.g. Composite Resins Filled = e.g. Composite Resins

5 UNFILLED ACRYLIC RESINS used late 1960’3 through early 1970’s. UNFILLED ACRYLIC RESINS used late 1960’3 through early 1970’s. Advantages - tooth coloured Advantages - tooth coloured - did not wash out - did not wash out - highly polishable - highly polishable - moderately strong - moderately strong Disadvantages - not colour stable Disadvantages - not colour stable - shrinkage/leakage - shrinkage/leakage

6 COMPOSITION Powder : Powder : Polymethyl Methacrylate Polymethyl Methacrylate Benzoyl Peroxide - Initiator Benzoyl Peroxide - Initiator Color pigments Color pigments Liquid : Liquid : Methyl Methacrylate monomer Methyl Methacrylate monomer Ethylene dimethacrylate (5%) – Cross linking Ethylene dimethacrylate (5%) – Cross linking agent. agent. Hydroquinone (0.06%) – Inhibitor. Hydroquinone (0.06%) – Inhibitor.

7 PROPERTIES  MECHANICAL PROPERTIES – Less Compressive Strength = 69 MPa Less Compressive Strength = 69 MPa Low Tensile Strength = 24 MPa Low Tensile Strength = 24 MPa Low Proportional limit. Low Proportional limit. Low Hardness = 15 KHN Low Hardness = 15 KHN Low Abrasion resistance. Low Abrasion resistance.

8  THERMAL PROPERTIES – ** Very high Coefficient of Thermal ** Very high Coefficient of Thermal expansion - ( 92.8 x 10 -6 / 0 C ) expansion - ( 92.8 x 10 -6 / 0 C ) “ It is 7-8 times greater than that of the tooth ” “ It is 7-8 times greater than that of the tooth ” ** Low Thermal Conductivity. ** Low Thermal Conductivity.

9  POLYMERIZATION SHRINKAGE – High 5 to 8 %. High 5 to 8 %.  SOLUBILITY – Insoluble in water & oral fluids. Insoluble in water & oral fluids.  WATER SORPTION – Sorb water 1.7 mg / cm 3 Sorb water 1.7 mg / cm 3

10  ADHESION – Does not adhere to Enamel or Dentin. Does not adhere to Enamel or Dentin.  ESTHETICS – Excellent matching with tooth color, but tends Excellent matching with tooth color, but tends to discolor. to discolor.  BIOCOMPATIBILITY – Monomer can penetrate dentinal tubules & Monomer can penetrate dentinal tubules & cause irritation to the pulp. cause irritation to the pulp.

11 MANIPUPLATION Bulk Technique or Pressure Technique Bulk Technique or Pressure Technique Incremental or Non-pressure Technique Incremental or Non-pressure Technique Flow Technique Flow Technique

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13  It is a tooth colored restorative material, developed in early 1960’ s. developed in early 1960’ s. Features :::: Features :::: * Strengthened by adding Silica particles * Strengthened by adding Silica particles * Acid Etching technique * Acid Etching technique * Bonding technique * Bonding technique

14  A Composite is a system composed of a mixture of 2 or more components, which mixture of 2 or more components, which are essentially insoluble in each other and are essentially insoluble in each other and differ in form. differ in form. Major components – Resin Matrix Major components – Resin Matrix Inorganic Filler Inorganic Filler

15 Advantages - tooth colored - stain resistant - stain resistant - polishable - polishable - can be bonded to tooth - can be bonded to tooth - strong - strong - wear resistant - wear resistant Disadvantages - shrinkage (2-5%) - longevity ?? - longevity ??

16 ** Different Composites are available for ** Different Composites are available for different purposes. different purposes. ** They are usually not Interchangeable. ** They are usually not Interchangeable. USES

17 Restoration of Anterior and Posterior teeth Restoration of Anterior and Posterior teeth -- Directly or as Inlays -- Directly or as Inlays USES ::

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19 To Veneer metal crowns and bridges. To Veneer metal crowns and bridges. USES ::

20 Esthetic Laminates Esthetic Laminates USES ::

21 To build up Cores (Post & Core). To build up Cores (Post & Core). USES ::

22 Pit and Fissure Sealant. Pit and Fissure Sealant. USES ::

23 Cementation of,,, Cementation of,,, Orthodontic brackets Orthodontic brackets Maryland Bridges Maryland Bridges Ceramic Crowns, Inlays & Onlays Ceramic Crowns, Inlays & Onlays Ceramic Laminates. Ceramic Laminates. USES ::

24 Cementation of Orthodontic brackets –

25 SUPPLIED AS – In a kit containing,,,,, Syringes of composite Syringes of composite resin pastes in various resin pastes in various shades. shades. Etching liquid (37 % Etching liquid (37 % Phosphoric acid). Phosphoric acid). Enamel / Dentin Enamel / Dentin bonding agent. bonding agent. Shade guide. Shade guide.

26 COMPOSITION COMPOSITION ORGANIC RESIN MATRIX – ORGANIC RESIN MATRIX – BIS GMA or Urethane dimethacrylate, TEG DMA as a binder. BIS GMA or Urethane dimethacrylate, TEG DMA as a binder. INORGANIC FILLER – INORGANIC FILLER – Quartz, Colloidal silica or heavy metal glasses. Quartz, Colloidal silica or heavy metal glasses. COUPLING AGENT – COUPLING AGENT – Organo silanes. Organo silanes.

27 They also contain,,,,,  Hydroquinone – inhibitor to prevent premature polymerization. polymerization.  UV absorbers – to improve color stability.  Opacifiers – titanium oxide & aluminum oxide.  Color Pigments – to match tooth color.

28 RESIN MATRIX  It is ------- 50 % by volume 25 % by weight 25 % by weight  Most Composite resins utilize monomers that are aromatic or Aliphatic diacrylates. aromatic or Aliphatic diacrylates.  Commonly used monomers are,,,, BIS-GMA -- Bisphenol A – Glycidyl Methacrylate BIS-GMA -- Bisphenol A – Glycidyl Methacrylate UDMA -- Urethane dimethacrylate UDMA -- Urethane dimethacrylate

29 Limitation Of Monomers,,,,,,, Extremely Viscous at room temperature. Extremely Viscous at room temperature. To make it clinically acceptable Diluent monomers are added to the resin matrix to,,,,, Diluent monomers are added to the resin matrix to,,,,,  reduce the viscosity of the paste  allow more filler particles to be incorporated  allow cross-linking b/w chains

30 Commonly used Diluent monomer is TEGDMA - Triethylene Glycol Dimethacrylate TEGDMA - Triethylene Glycol Dimethacrylate They form highly cross linked polymer structure. They form highly cross linked polymer structure.

31 FILLER PARTICLES Improves materials properties. Improves materials properties. It is -------- 30 to 70 % by volume 50 to 85 % by weight 50 to 85 % by weight Advantages ::::: Curing shrinkage is reduced, as less resin is present Curing shrinkage is reduced, as less resin is present Reduces water sorption Reduces water sorption Reduces Coefficient of Thermal expansion Reduces Coefficient of Thermal expansion Improves mechanical properties - like Strength, Improves mechanical properties - like Strength, Hardness, & Abrasion resistance. Hardness, & Abrasion resistance.

32 TYPES OF FILLERS – Composite resins use 3 types of fillers,,,, Quartz Quartz Colloidal Silica Colloidal Silica Glasses or Ceramic containing heavy metals Glasses or Ceramic containing heavy metals

33 QUARTZ – Obtained by grinding or milling quartz. Obtained by grinding or milling quartz. Particle size = 0.1 to 100 μm. Particle size = 0.1 to 100 μm. Mainly used in Conventional composites. Mainly used in Conventional composites. They are chemically inert but is very hard. They are chemically inert but is very hard.

34 COLLOIDAL SILICA –  Particle Size = 0.02 to 0.04 μm.  Reffered to as microfillers.  Obtained by a Pyrolytic or a Precipitation process.  They are added in small amount (5 wt. %) to modify the paste viscosity. modify the paste viscosity.  Have large surface area (50 to 300 m 2 / g).  Only inorganic filler in microfilled composites.

35 GLASSES / CERAMIC CONTAINING HEAVY METALS – These fillers provide radiopacity to the resin These fillers provide radiopacity to the resin restoration. restoration. Have refractory index of about 1.5 Have refractory index of about 1.5 Contain heavy metals such as – barium, strontium Contain heavy metals such as – barium, strontium & Zirconium. & Zirconium. Most commonly used is a barium glass. Most commonly used is a barium glass.

36 Factors that determine the properties & clinical application of composites,,,,,,  Amount of filler added  Size of particles & its distribution  Index of refraction  Radiopacity  Hardness

37 Amount of filler added –  Affected by the relative surface areas large surface area -- small amounts of filler large surface area -- small amounts of filler e.g. - colloidal silica e.g. - colloidal silica

38 Size of particles – In order to increase the filler amount in the resin, it is In order to increase the filler amount in the resin, it is necessary to add the fillers in a range of particle sizes. necessary to add the fillers in a range of particle sizes. Refractive Index – Filler should have a translucency similar to the tooth Filler should have a translucency similar to the tooth structure. structure. Most glass & quartz fillers have a refractive index Most glass & quartz fillers have a refractive index of 1.5. of 1.5.

39 Radiopacity – Provided by a number of glasses and ceramics Provided by a number of glasses and ceramics that contain heavy metals such as barium, that contain heavy metals such as barium, strontium and zirconium. strontium and zirconium. Most commonly used is a Barium Glass. Most commonly used is a Barium Glass.

40 COUPLING AGENTS – Bond the filler particles to the resin matrix. Bond the filler particles to the resin matrix. Most commonly used coupling agents are Most commonly used coupling agents are organosilanes ( 3-methoxy-propyl-trimethoxy- silane ). organosilanes ( 3-methoxy-propyl-trimethoxy- silane ). Zirconates & Titanates can also be used as Zirconates & Titanates can also be used as coupling agent. coupling agent.

41 Advantages of Coupling agents – Bond the filler particles to the resin matrix. Bond the filler particles to the resin matrix. Improve the physical & mechanical properties of Improve the physical & mechanical properties of the resin. the resin. Provide hydrolytic stability by preventing water Provide hydrolytic stability by preventing water from penetrating along the filler – resin interface. from penetrating along the filler – resin interface.

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43  ACCORDING TO POLYMERIZATION REACTION :: REACTION ::  Chemically / Self Activated Composite Resins  Light Activated Compostie Resins * Ultraviolet (UV) light * Ultraviolet (UV) light wave length = 200 – 400 nm wave length = 200 – 400 nm * Visible light * Visible light wave length = 420 – 450 nm wave length = 420 – 450 nm

44  ACCORDING TO THE FILLER SIZE :: Average Particle size Average Particle size Conventional / Macrofilled 8 - 12 μm Small particle 1 - 5 μm Microfilled 0.04 - 0.4 μm Hybrid 1.0 μm

45  ACCORDING TO THE USE ::  For Anterior teeth restoration e.g. - Microfilled e.g. - Microfilled  For Posterior teeth restoration e.g. - Conventional & Hybrid e.g. - Conventional & Hybrid

46 TYPE OF COMPOSITES ACCORDING TO POLYMERIZATION REACTION

47  CHEMICALLY ACTIVATED RESINS Two Paste system – Two Paste system – * Base Paste contains,,,, * Base Paste contains,,,, Benzoyl peroxide - initiator Benzoyl peroxide - initiator * Catalyst Paste contains,,,, * Catalyst Paste contains,,,, Tertiary amine - activator Tertiary amine - activator (N-N dimethyl - p - toluidine) (N-N dimethyl - p - toluidine)

48  Setting Reaction --- When 2 pastes are spatulated, the amine reacts with When 2 pastes are spatulated, the amine reacts with the Benzoyl peroxide to form the free radicals which the Benzoyl peroxide to form the free radicals which starts the polymerization. starts the polymerization.

49  LIGHT ACTIVATED RESINS  UV - Light activated systems ::: It is the first light activated system to activate the It is the first light activated system to activate the free radicals. free radicals. Limitations,,,,, Limited penetration of the light into the resin. Thus Limited penetration of the light into the resin. Thus difficult to polymerize thick sections. difficult to polymerize thick sections. Lack of penetration through tooth structure. Lack of penetration through tooth structure.

50  Visible - Light activated systems ::: Ability to polymerize thicker sections. Ability to polymerize thicker sections. Totally replaced the UV light system. Totally replaced the UV light system. Most widely used than the chemically activated system. Most widely used than the chemically activated system. Supplied as,,,,,,, Single paste system, containing – Single paste system, containing – Photoinitiator ----- Camphoroquinone 0.25 wt. % Photoinitiator ----- Camphoroquinone 0.25 wt. % Amine accelerator ----- DEAEMA 0.15 wt. % Amine accelerator ----- DEAEMA 0.15 wt. % (Diethyl-amino-ethyl-methacrylate) (Diethyl-amino-ethyl-methacrylate)

51  Setting reaction,,,,, When exposed to light of the correct wave length When exposed to light of the correct wave length ( 400 -500 nm ) the photoinitiator is activated and ( 400 -500 nm ) the photoinitiator is activated and reacts with the amine to form the Free radicals. reacts with the amine to form the Free radicals.

52 LIGHT DEVICES / LIGHT CURING UNITS – Transmit light of the proper wavelength to the site Transmit light of the proper wavelength to the site of the restoration, by means of light guide composed of the restoration, by means of light guide composed of fiberoptic bundles. of fiberoptic bundles.

53 ARGON LASER L E D CORDLESSLASER

54 Light source is usually a Tungsten Halogen Light source is usually a Tungsten Halogen light bulb. light bulb. White light is generated by the bulb passes White light is generated by the bulb passes through the filter that removes the infrared & through the filter that removes the infrared & visible spectrum for wavelength greater than visible spectrum for wavelength greater than about 500 nm. about 500 nm.

55 DEGREE OF CONVERSION / POLYMERIZATION – Conversion of monomer to polymer (polymerization) depends on – Transmission of light through the material -- Controlled Transmission of light through the material -- Controlled by absorption & scattering of light by Filler particles by absorption & scattering of light by Filler particles Amount of Photoinitiator & Inhibitor present Amount of Photoinitiator & Inhibitor present Time of exposure – Low intensity light = 80 to 240 sec. Time of exposure – Low intensity light = 80 to 240 sec. High intensity light = 20 to 60 sec. High intensity light = 20 to 60 sec.

56 OPTICAL MODIFIERS – To simulate tooth structure,Translucency or Opacity is provided by adding minute amount of To simulate tooth structure,Translucency or Opacity is provided by adding minute amount of Optical modifiers, such as,,,,,,,, Optical modifiers, such as,,,,,,,, Titanium dioxide Titanium dioxide & =.001 to.007 wt. % & =.001 to.007 wt. % Aluminu oxide Aluminu oxide

57 SELF ACTIVATED LIGHT ACTIVATED SELF ACTIVATED LIGHT ACTIVATED  Activated by peroxide - Requires light of correct amine system. wavelength. amine system. wavelength.  Bulk placement. Layer by layer placement.  Cures throughout its Cures only where light is bulk. received. bulk. received.  More porosity. Less porosity.  Requires mixing. No mixing.  Less Working time. More Working time.  Discolored fast. Resistant to Discoloration.  More Wastage. Less Wastage.  Short Shelf life. Long Shelf life.  Requires waiting period Can be finished immediately for finishing. after curing. for finishing. after curing.

58 TYPE OF COMPOSITES ACCORDING TO FILLER SIZE

59 CONVENTIONAL COMPOSITES  Also known as ----- TRADITIONAL COMPOSITES OR MACROFILLED COMPOSITES TRADITIONAL COMPOSITES OR MACROFILLED COMPOSITES

60  COMPOSITION – Ground Quartz is most commonly used as filler. Ground Quartz is most commonly used as filler. Wide distribution of particle size. Wide distribution of particle size.  Particle Size = 8 to 12 μm But may be as large as 50 to 100 μm. But may be as large as 50 to 100 μm.  Filler loading = 70 to 80 wt. % or or 50 to 60 vol. % 50 to 60 vol. %

61  PROPERTIES –  Compressive strength -- 250 to 300 MPa 4 to 5 times greater than unfilled resin. 4 to 5 times greater than unfilled resin.  Tensile strength -- 50 to 65 MPa Double that of Unfilled resin. Double that of Unfilled resin.  Elastic modulus -- 8 to 15 GPa 4 to 6 times greater than Unfilled resin. 4 to 6 times greater than Unfilled resin.

62  Hardness -- 55 KHN 3 to 4 times greater than Unfilled resin. 3 to 4 times greater than Unfilled resin.  Water sorption -- 0.5 to 0.7 mg/cm 2 3 times Less than that of Unfilled resin. 3 times Less than that of Unfilled resin.  Co-Efficient of thermal expansion -- 25 to 35 x 10 -6 / 0 C 3 to 4 times less than Unfilled resin. 3 to 4 times less than Unfilled resin.

63  Esthetics -- * Polishing of Conventional composite results in * Polishing of Conventional composite results in a rough surface. a rough surface. * Tendency to stain over a period of time. * Tendency to stain over a period of time.  Radiopacity -- * Composites using Quartz as a filler are radioluscent. * Composites using Quartz as a filler are radioluscent. * Radiopacity is less than dentin. * Radiopacity is less than dentin.

64 CLINICAL CONSIDERATION – Rough surface develops as a result of abrasive wear of the soft resin matrix, due to tooth brushing and mastication. Rough surface develops as a result of abrasive wear of the soft resin matrix, due to tooth brushing and mastication. Poor resistance to Occlusal wear. Poor resistance to Occlusal wear. Tendency to Discolor, due to rough surface. Tendency to Discolor, due to rough surface. Resin matrix does not bond to tooth structure. Resin matrix does not bond to tooth structure.

65 MICROFILLED COMPOSITES MICROFILLED COMPOSITES Also known as Nanofilled Composites. Also known as Nanofilled Composites. Developed to overcome the problems of Developed to overcome the problems of surface roughness of Conventional surface roughness of Conventional Composites. Composites. Smoother surface, due to incorporation of Smoother surface, due to incorporation of microfillers. microfillers.

66 COMPOSITION -- Colloidal Silica used as a microfillers (inorganic filler) Colloidal Silica used as a microfillers (inorganic filler) Particle size of Colloidal silica,,,,, Particle size of Colloidal silica,,,,, 0.02 to 0.04 μm 0.02 to 0.04 μm 200 to 300 times smaller than the quartz fillers 200 to 300 times smaller than the quartz fillers of Conventional composites. of Conventional composites.

67  Problem with Colloidal Silica,,,,, It has a large surface area that could not be It has a large surface area that could not be adequately wetted by the resin matrix. adequately wetted by the resin matrix.  Inorganic Filler content / loading,,,,,, only 50 % by wt. only 50 % by wt. ( Conventional composite has 70-80 wt. % ) ( Conventional composite has 70-80 wt. % )

68 Methods to increase Filler loading ::  Sinter the colloidal silica,,, thereby forming larger agglomerate which results in thereby forming larger agglomerate which results in reduced surface area. reduced surface area.

69  Addition of Prepolymerized fillers,,, Also known as Organic fillers. Also known as Organic fillers. This is most common method. This is most common method. Prepared by adding 60 -70 wt.% of silane Prepared by adding 60 -70 wt.% of silane coated colloidal silica to the monomer, which coated colloidal silica to the monomer, which is held at slight high temp. to reduce the is held at slight high temp. to reduce the viscosity. viscosity. It is then heat cured & ground. It is then heat cured & ground.

70  Inorganic filler content after inclusion of Prepolymerized fillers,,,,, Prepolymerized fillers,,,,, 80 % by wt. 80 % by wt. 70 % by vol. 70 % by vol.

71  PROPERTIES –  Except Compressive strength, all other physical & mechanical properties are inferior to the other mechanical properties are inferior to the other composite resins. composite resins.  COMPRESSIVE STRENGTH :: 250 to 350 MPa. 250 to 350 MPa. Similar to Conventional composites. Similar to Conventional composites.

72  TENSILE STRENGTH :: 30 to 50 MPa. 30 to 50 MPa. Lowest among composites. Lowest among composites.  MODULUS OF ELASTICITY :: 3 to 6 MPa 3 to 6 MPa Lowest. Lowest.  HARDNESS :: 25 to 30 KHN 25 to 30 KHN Lowest. Lowest.

73  THERMAL EXPANSION COEFFICIENT :: 50 to 60 x 10 -6 / 0 C 50 to 60 x 10 -6 / 0 C Highest among the composite resins. Highest among the composite resins.  WATER SORPTION :: 1.4 to 1.7 mg / cm2 1.4 to 1.7 mg / cm2 Highest Highest  ESTHETICS :: Provide Smooth finished surface desired for Provide Smooth finished surface desired for esthetics. esthetics.

74 CLINICAL CONSIDERATIONS –  Resin of choice for esthetic restoration of anterior teeth, especially in non – stress bearing area. teeth, especially in non – stress bearing area.  Potential for greater fracture in Class IV & II restorations. restorations.

75 SMALL PARTICLE COMPOSTIE Introduced in an attempt to have good Introduced in an attempt to have good surface smoothness with improved surface smoothness with improved Physical & Mechanical properties. Physical & Mechanical properties.

76  COMPOSTION – Inorganic fillers are ground to smaller size than the Inorganic fillers are ground to smaller size than the Conventional composites. Conventional composites. Average Filler Size,,,, Average Filler Size,,,, 1 – 5 μm but broad distribution. 1 – 5 μm but broad distribution. Filler content / loading,,,, Filler content / loading,,,, 80 % by wt. 80 % by wt. 70 % by vol. 70 % by vol.

77 ** Primary filler is silane - coated ground particles. ** Primary filler is silane - coated ground particles.  Fillers utilize,,,, Glasses containing heavy metal. Ground quartz Glasses containing heavy metal. Ground quartz is also used. is also used. Colloidal silica is also added in small amounts Colloidal silica is also added in small amounts i.e. 5 wt.% to adjust the paste viscosity. i.e. 5 wt.% to adjust the paste viscosity.

78  PROPERTIES – Best physical & mechanical properties, due to higher filler content. Best physical & mechanical properties, due to higher filler content. Compressive Strength :: 350 to 400 MPa Highest Highest Tensile Strength :: 75 to 90 MPa Double than Microfilled & 50% greater than Double than Microfilled & 50% greater than that of Conventional composite. that of Conventional composite.

79 Modulus of Elastisity :: 15 to 20 GPa Stiffest of all Stiffest of all Hardness :: 50 to 60 KHN Similar to Conventional Similar to Conventional Thermal Expansion Coefficient :: 19 to 26 x 10 -6 / 0 C Lower than other Composites, but twice that of Lower than other Composites, but twice that of tooth structure. tooth structure.

80 Water Sorption :: 0.5 to 0.6 mg / cm 2 similar to Conventional. similar to Conventional. Esthetics :: Better than conventional. Polymerization Shrinkage :: Less than conventional. Radiopacity :: Contains heavy metal glasses as fillers, which are radiopaque. fillers, which are radiopaque. Important property for material used Important property for material used in posterior teeth. in posterior teeth.

81  CLINICAL CONSIDERATION – Can be used in areas of stress, such as Class IV & II Can be used in areas of stress, such as Class IV & II restoration. restoration. Provides smooth surfaces for anterior teeth, but are Provides smooth surfaces for anterior teeth, but are still not as good as Microfilled & Hybrid composites. still not as good as Microfilled & Hybrid composites.

82 HYBRID COMPOSITES Latest category of composite material. Latest category of composite material. Developed to obtain better surface smoothness than Developed to obtain better surface smoothness than the Small particles, yet maintaining the properties. the Small particles, yet maintaining the properties. Have surface smoothness & esthetics competitive with Have surface smoothness & esthetics competitive with Microfilled composites for anterior restorations. Microfilled composites for anterior restorations.

83 COMPOSITION – Filler content – Filler content – 75 to 80 % by wt. 75 to 80 % by wt. 60 to 65 % by Vol. 60 to 65 % by Vol.

84 Two kinds of filler particles are employed,,,, Colloidal Silica – Colloidal Silica – Present in a higher concentration 10 to 20 wt % Present in a higher concentration 10 to 20 wt % Ground particles of Glasses containing heavy metals – Ground particles of Glasses containing heavy metals – * Average particle size = 0.6 to 1 μm * Average particle size = 0.6 to 1 μm * 75 % of the ground particles are smaller * 75 % of the ground particles are smaller than 1.0 μm. than 1.0 μm.

85 PROPERTIES – Range between Conventional & Small particle Range between Conventional & Small particle composites, but generally superior to Microfilled. composites, but generally superior to Microfilled. Compressive Strength :: 300 to 350 MPa Slightly less than the Small particle composite. Slightly less than the Small particle composite. Tensile Strength :: 70 to 90 MPa Comparable to Small particle composite. Comparable to Small particle composite.

86 Elastic Modulus :: 7 to 12 GPa Ranges b/w Conventional & Microfilled composites. Ranges b/w Conventional & Microfilled composites. Hardness :: 50 to 60 KHN Similar to Small particle composites. Similar to Small particle composites. Coefficient of Thermal Expansion :: 30 to 40 x 10 -6 / 0 C Less than the Microfilled. Less than the Microfilled.

87 Water Sorption :: 0.5 to 0. 7 mg / cm 2 Similar to Conventional & Small partilce, but less Similar to Conventional & Small partilce, but less than Microfilled composites. than Microfilled composites. Esthetics :: Competitive to Microfilled composite for anterior Competitive to Microfilled composite for anterior teeth. teeth. Radiopacity :: Presence of heavy metal glasses makes it more Presence of heavy metal glasses makes it more radio – opaque than Enamel. radio – opaque than Enamel.

88 CLINICAL CONSIDERATION – Widely used for Anterior restoration, including Widely used for Anterior restoration, including Class IV. Class IV. Also used in stress – bearing area, even though its Also used in stress – bearing area, even though its mechanical properties are inferior to Small particle mechanical properties are inferior to Small particle composties. composties.

89 COMPOSITE RESINS FOR POSTERIOR RESTORATIONS COMPOSITE RESINS FOR POSTERIOR RESTORATIONS

90  All types of Composites are used for posterior restorations. restorations.  Cavity preparation should be Conservative and should use adequate manipulation and should use adequate manipulation technique. technique.

91 INDICATIONS OF COMPOSITE FOR POSTERIOR TEETH – INDICATIONS OF COMPOSITE FOR POSTERIOR TEETH – When Esthetics is necessary. When Esthetics is necessary. When pt. is Allergic to mercury. When pt. is Allergic to mercury.

92 PROBLEMS IN USE OF COMPOSITES FOR POSTERIOR RESTORATIONS –  In Class V restoration, when gingival margin is located in cementum or when gingival margin is located in cementum or dentin, the material shrinks away from the margin dentin, the material shrinks away from the margin leading to a gap. leading to a gap.  Placement technique is more time consuming.

93 Composites wear faster than Amalgam. Composites wear faster than Amalgam. Newer materials like Small particle & Hybrid Newer materials like Small particle & Hybrid have less wear ( 20 um per year ) which have less wear ( 20 um per year ) which approaches that of Amalgam ( 10 um per year ). approaches that of Amalgam ( 10 um per year ).

94 MANIPULATION OF COMPOSITE RESINS OR TECHNIQUES OF INSERTION

95 CHEMICALLY ACTIVATED COMPOSITES 2 paste systems. 2 paste systems. Equal amount of paste are dispensed onto a mixing pad. Equal amount of paste are dispensed onto a mixing pad. Mixing by rapid spatulation for 30 sec. with Plastic Mixing by rapid spatulation for 30 sec. with Plastic instrument. instrument. Inserted with plastic instrument or syringe. Inserted with plastic instrument or syringe. Matrix strip may be used to apply pressure for 15 min. Matrix strip may be used to apply pressure for 15 min.

96 LIGHT ACTIVATED COMPOSITES Single component pastes. Single component pastes. Require no mixing. Require no mixing. Working time is under the control of operator. Working time is under the control of operator. Exposure to curing light initiate polymerization. Exposure to curing light initiate polymerization. Exposure time is b/w 40 to 60 sec. Exposure time is b/w 40 to 60 sec. Depth of cure is limited. Depth of cure is limited. Resin thickness should not be greater than 2.5 mm. Resin thickness should not be greater than 2.5 mm.

97 ACID ETCHING TECHNIQUE – Most effective ways of improving the marginal seal & Most effective ways of improving the marginal seal & mechanical bonding b/w Resin and Enamel. mechanical bonding b/w Resin and Enamel. Mode Of Action :: It creates micro-porosities by etching of the enamel. It creates micro-porosities by etching of the enamel. Etching increase the surface area. Etching increase the surface area. Etched enamel has a high surface energy and allows a Etched enamel has a high surface energy and allows a resin to wet the surface & penetrate into micro-porosities resin to wet the surface & penetrate into micro-porosities

98 Acid Used :: 37 % Phosphoric acid is most commonly used acid. 37 % Phosphoric acid is most commonly used acid. Supplied in gel form. Supplied in gel form. Brush or Syringe is used for application on the Brush or Syringe is used for application on the enamel. enamel.

99 Procedure :: Dry the enamel surface completely. Dry the enamel surface completely. Length of application = 60 sec. Length of application = 60 sec. but may be 15 sec. but may be 15 sec. After etching, dried enamel shows white, frosted After etching, dried enamel shows white, frosted appearance. appearance. If enamel surface is contaminated, re-etching for 10 sec. If enamel surface is contaminated, re-etching for 10 sec.

100 BOND AGENTS – ENAMEL BOND AGENTS :: Unfilled resin ENAMEL BOND AGENTS :: Unfilled resin DENTIN BOND AGENTS :: DENTIN BOND AGENTS :: First generation First generation Second generation Second generation Third generation Third generation Forth generation Forth generation Fifth generation Fifth generation Primers / Conditioners Bonding liquid

101 SANDWICH TECHNIQUE -- Tooth surface + GIC + Composite

102 PIT & FISSURE SEALANTS -- Cyanoacrylate Cyanoacrylate Polyurethenes Polyurethenes BIS - GMA BIS - GMA


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