Back round about compositeDental composite resins are types of synthetic resins which are used in dentistry as restorativematerial oradhesives.The term composite refers to a 3D structure of at least2 chemically different materialsThe binding resin and the filling material are calledphasesComposite resins are most commonly composite cavity restorations when used with dentin and enamel bonding techniques restore the toothback to near its original physical integrity
Steps in Composite restoration1.local anasthesia 2.Preparation of operating site3.Shade selection4.Isolation of operationg site5.Tooth preparation6.Preliminary steps of enamel & dentin bonding7.Matrix placement8.Insertind the composite9.Contouring the composite10.Polishing the composite
Tooth preporationTooth preparation often defines restoration strength.Small tooth defects which receive minimal force require minimal tooth preparationbecause only bond streng this required toprovide retention and resistance.In larger tooth defects where maximum forces are applied, mechanical retention andresistance with increased bond area can berequired to provide adequate strength.
Tooth preparation ,by instrument high speed, requires adequate access to remove caries,removal of caries by low-speed, elimination ofweak tooth structure that could fracture, beveling of enamel to maximize enamel bond strength,and extension into defective areas such asstained grooves and decalcified area,which provides retention for the restoration.
Acid burning method & bonding: After cavity preparation and cleaning ion the enamel margins of the cavity the doctor put acid (phosphoric acid50%). After burning doctor washes and dries the surface.The enamel shouldlook like chuck.The main advantage of using composite resin materials isthat a complete seal can be achieved if acid etching ofthe enamel cavity wall is performed prior to insertion ofthe materials. Acid etching results in a ragged, porouscavity wall and enamel surface which provides retentionfor the restoration.The composite itself cant enter the small hollows in the enamel, to solve this doctor uses bonding agent.Bonding agent attaches to enamel mechanically,
The preparation should be as narrow as technicallypossible withoutany bevel in the occlusal fissure area and straighted wallsMatrix systems are placed to contain materials within the tooth and form proper interproximal contours andcontactsEnamel and dentin bonding is completed Composite shrinks when cured so large areas must be layered to minimize negative forcesGenerally any area thicker than 2 mm requires layering Composite curing when touching multiple walls creates dramatic stress and should be avoided.Composite built in layers replicate tooth structure by placing dentin layers first and then enamel layersFinal contouring with hand instruments is ideal to minimize the trauma of shaping with burs
when working with UV light or visible light there is no limit on time. In chemical activation the working time is 60-90sec.Hardening time – in most composite 3 min in this time the composite must remain untouched, afterthis time the doctor can polish the compositeMatrix systems are removed and refined shaping and occlusal adjustment done with a 245 bur and aflame shaped finishing bur.Interproximal buccal and lingual areas are trimmed of excess with a flame shaped finishing bur.Final polish is achieved with polishing cups, points,sandpaper disks and polishing paste.