Chapter 4 Direct Esthetic Restorative Materials PDF

DIRECT ESTHETIC RESTORATIVE MATERIALS CHAPTER 4 4 TYPES OF MATERIALS USED AS DIRECT ESTHETIC DENTAL RESTORATIONS DIRECT ESTHETIC RESTORATIVE MATERIALS 1. Composites 2. Compomers 3. Hybrid Ionomers 4 Glass Ionomers. 4 TYPES OF MATERIALS USED AS DIRECT ESTHETIC DENTAL REST...

DIRECT ESTHETIC RESTORATIVE MATERIALS CHAPTER 4 4 TYPES OF MATERIALS USED AS DIRECT ESTHETIC DENTAL RESTORATIONS DIRECT ESTHETIC RESTORATIVE MATERIALS 1. Composites 2. Compomers 3. Hybrid Ionomers 4 Glass Ionomers. 4 TYPES OF MATERIALS USED AS DIRECT ESTHETIC DENTAL RESTORATIONS Composites - Are esthetic, strong, and wear resistant but 1 have low or no flouride release. Introduced about 1960.. Compomers - Are less wear resistant but are esthetic 2 and release flouride.. Hybrid Ionomers - Release more fluoride than compomers do 3 but are not so wear resistant and are not used in. posterior restorations. Introduced in the early 1990s 4 Glass Ionomers - Release the most fluoride and are. best for high caries risk patients in low-stress applications. Introduced in 1972.  COMPOSITES COMPOSITION & REACTION Three phases: resin matrix, dispersed inorganic filler particles, & silane coupling agent. Filler size: 0.5 t o 3 um (fine particles) or 0.04 um (microfine particles) Filler Composition: Quartz, lithium aluminum silicate, and barium, strontium, zinc, or ytterbium glasses. COUPLING AGENTS To provide a good bond between the inorganic fillers and the resin matrix. RESIN MATRIX The most common resin are based ondimethacrylate or urethane dimethacrylate oligomers. INITIATORS AND ACCELERATORS Must be kept separated and not mixed until just before the restoration is placed. PIGMENTS Inorganic pigments are added in small amounts so th at the color of the composites matches tooth structure.  PROPERTIES 1. Low polymerization shrinkage 6. Radiopacity 2. Low water sorption 7.High bond strength t o enamel 3. Coefficient of thermal and dentin expansion similar t o tooth 8.Good color match t o tooth structure structure 9. Ease of manipulation 4. High fracture resistance 10.Ease of finishing and 5. High wear resistance polishing POLYMERIZATION SHRINKAGE - Microhybrid composites shrink less during setting than microfilled types do, since the microhybrid composites have less resin. THERMAL CONDUCTIVITY - Much lower than th at for metallic restoration. THERMAL EXPANSION - Greater than th at of tooth structure. WATER SORPTION - Accompanied by swelling of the composite, but i t has not been an effective way t o counteract polymerization shrinkage. RADIOPACITY - Most microhybrid composites are radiopaque. COMPRESSIVE AND FLEXURAL STRENGTHS - Compressive strength of microhybrid composites is higher than th at of microfilled composites. ELASTIC MODULUS - Elastic modulus or stiffness, of the composites is dominated by the amount of filler and increases exponentially with the volume fraction or filler. HARDNESS AND WEAR - Knoop hardness of composites is exponentially related t o the volume fraction of filler and is less related t o the hardness of the filler. BOND STRENGTH - The bond strength of composites t o acid-etched enamel and dentin are about the same when a universal bonding agent is used. Wear QUALITIES composite are superior materials from anterior restorations esthetics are essential and closer forces are low. Wear of posterior composite restorations is observed a t the contact area where stresses are the highest Postoperative Sensitivity Sensitivity associated with composite restorations has been reported in about 10% of cases. ETCHING AND BONDING MANIPULATION provide a bond between the composite tooth structure which the enamel and dentin of the cavity preparation with acid for 30 seconds SINGLE-PASTE COMPOSITE Supplied in various shades in disposable syringes, spills and compules. OPAQUE PLASTIC protect the material from exposure to light does provide adequate shelf life. COMPULES place on the end of the syringe paste is extruded af ter removal for the protective tip Advantages: ease of placement of the composite paste decrease in cross infection protection of the paste from exposure to ambient light Two-paste composites one syringe contains the peroxide initiator or catalyst other syringe includes the amine accelerator setting time is about 4 to 5 minutes Dual-cured composites contain both chemical accelerators and light activators so that polymerization can be initiated by light and then continued by the self-cured mechanism. Pulpal protection pulp may be protected with a cavity liner or glass ionomer, hybrid ionomer or compomer base. Insertion insert the mixed materials into the cavity preparation by several methods composite may also be placed into the plastic tip of a syringe Finishing and polishing gross reduction used diamonds carbide finishing burs finishing disks strips of alumina Finishing should be done in a wet field with a water soluble lubricant.  Composites for special applications Flowable composites Condensable (packable) composites Laboratory Composites Core buildup composites Provisional Composites Repair of ceramic Composites Flowable composites light cured, low viscosity composites are recommended for cervical lesions, pediatric restorations, other small low stress bearing restorations low modulus of elasticity Condensable (packable) composites compost of light activated dimethacrylate resins with fillers that are fibers Important properties: high depth of cure low polymerization shrinkage radiopacity low wear rate Laboratory composites -crown, inlays, veneers bonded to metal substructures -metal three bridges are prepared indirectly on dies -combined with fiber reinforcement (FibreKor, Vectris) Core buildup composites -tooth structure is lost from caries -tooth must be build up to receive a crown -usually tinted (blue, white, pink) Advantages: -can be bonded to dentin -can be finished immediately -are easy to contour -have high rigidity -have good color under porcelain Provisional Composites temporary inlays, crowns and long-span bridges fabricated from composite or acrylic resins Purposes: maintain the position of the prepared tooth seal and insulate the preparation and protect the margins establish proper vertical dimension aid in diagnosis and treatment planning evaluate esthetic replacement Repair of ceramic or composites bond strength between the remaining ceramic accomplished by abrading of the surface of the remaining composite Compomers composite modified with polyacid groups used for restorations in low stress bearing areas Composition and reaction contains monomers modified by polyacid groups are formulated without water filler volume percentage ranges 42% t o 67% average filler particle size ranges 0.8 t o 5.0 Properties Release fluoride by a mechanism similar t o th at of glass and hybrid ionomers Do not recharge from fluoride treatments Manipulation Formulated as a single paste packaged in unit-dose compules Require a bonding agent t o bond GLASS IONOMER USED IN CERVICAL AND CLASS 5 RESTORATION -WHERE ESTHETICS IS NOT CRITICAL Composition and Reaction: SUPPLIED AS POWDERS (ALUMINOSILICATE GLASS) OF VARIOUS SHADES AND SHADES Properties: PROPERTIES ESPECIALLY NOTEWORTHY ARE A MODULUS THAT IS SIMILAR TO DENTIN THE BOND STRENGTH OF GLASS IONOMERS TO DENTIN IS LOWER THAN THAT OF COMPOSITES THE FLUORIDE IN THE GLASS IONOMER IS RELEASED OVER A PERIOD OF 2 YEARS Manipulation: PACKAGED IN BOTTLES AND CAPSULES MIXING TIME – 30 TO 40 SECONDS SETTING TIME – 4 MINUTES HYBRID IONOMER resin-modified glass ionomer used for restoration in low-stress bearing areas Composition and Reaction: the powder is similar t o that of glass ionomer the liquid contains monomers, poly acids, and water Properties: bond t o tooth structure without the use of a dentin- bonding agent i t recharge when exposed t o fluoride treatments or fluoride dentifrices Manipulation: packaged as powder-liquid or encapsulated forms  BONDING USED WITHAGENTS COMPOSITES TO PROVIDE AN ADEQUATE BOND TO ENAMEL AND DENTIN AVAILABLE AS LIGHT-CURED AND DUAL-CURED, MULTIBOTTLE SYSTEMS AND LIGHT CURED Composition and Reaction: consist of 3 components –etchant, primer, and adhesive etchant typically is 37% phosphoric acid primer and adhesive are usually carried in a solvent such as acetone, alcohol, or water Composition and Reaction: Bonding t o etched enamel is micromechanical Bonding t o dentin requires the removal of the smear layer The bonding agent is polymerized separately from the composite Regardless of the system, follow these general directions: 1.isolate the surface 2. maintain a clean, moist surface 3. follow the manufacturer’s directions carefully 4. use a protective liner for deep cavities 5. provide mechanical retention in the cavity design LIGHT-CURING UNITS LIGHT SOURCE IS USUALLY A QUARTZ-HALOGEN BULB LIGHT IS FILTERED TO PROVIDE ONLY BLUE LIGHT SOME LAMPS PRODUCE CONSIDERABLE HEAT WHICH CAN PRODUCE PULPAL IRRITATION TIMES MAY VARY FROM 20-30 SECONDS MICROFILLED COMPOSITES REQUIRE LONGER EXPOSURE THAN MICROHYBRID COMPOSITES THANK YOU FOR LISTENING! 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