Adobe Systems Restorative dentistry 3rd year Lecture 1 L. Roubalíková Adobe Systems Preparation of dental caries (cavity preparation) • ØInstrumental treatment that removes dental caries ØThe rest of the tooth must be restorable with filling materials ØThe rest of the tooth as well as the filling must be resistant against occlusal forces ØThe risk of secondary caries must be minimized Ø Ø Adobe Systems Step by step procedure •Acces to the cavity •Preparation of cavosurface margin and •Extention for prevention •Retention of the filling •Resistance of the restored tooth •Excavation of carious dentin •Finishing of the walls •Final control (light, mirror, magnification) • Adobe Systems Basic rules •Acces to the cavity • •Preparation through the hard dental tissues •Removal the undermined enamel •Separation of teeth •Separation or removal of gingiva vychozistav preparačni nastroje zacatekpreparacekavity vylomeni kavitankavitasklinkem Adobe Systems • Kopie kaz preparačni nastroje daniel8 pristup do kavity Old filling is being removed M:\obrazové a případové případové studie\pripad 02\DSC_0355.JPG Adobe Systems Basic rules •Preparation of cavity borders and extention •for prevention (Cavosurface margin) • •Depends on •Dental material •Oral hygiene • •Precautions of secondary caries • Adobe Systems Basic rules • •Retention of the filling • •Precautions of its lost •Macromechanical retention •Micromechanical retention •Chemical retention Adobe Systems Basic rules •Resistance of the restored tooth • •Against occlusal and other forces • •Depends on -Material -Individual occlusal forces • Adobe Systems Basic rules • •Excavation of carious dentin • •Necessary (risk of recurrent caries) • •Ball shaped (spheric) bur - slow speed (3000 rpm) •or •Excavator (hand instrument) • Adobe Systems Basic rules •Finishing of the walls • •Depends on the kind of material -Bevel or without bevel -Fine diamond bur • Adobe Systems Basic rules •Final control • •Direct or indirect view •Good illumination •Magnification • • Adobe Systems Preparation •Hand •Excavator, cleaver • •Power driven •Burs, diamonds Adobe Systems Chisel – for enamel Cleaver Black_dlátko_na_sklovinu Adobe Systems Chisel for enamel Black_dlátko_na_sklovinu_zahnuté Adobe Systems Excavator Exkavátor_oboustranný Adobe Systems Instruments for cavity preparation •Power driven (powered) instruments for cutting -Rotary instruments •Comon design characteristics • lenka.roubalikova@tiscali.cz shank neck head Adobe Systems Cutting instruments - burs •Steel •Tungsten carbide Adobe Systems Cutting instruments – burs head shapes •Round (ball shaped) • vrtáčky2 Adobe Systems Cutting instruments – burs head shapes •Fissure with flat end • •Fissure with pointed end •Straight or tapered form • vrtáčky2 Adobe Systems Cutting instruments – burs head shapes •Pear • vrtáčky2 Adobe Systems Cutting instruments – burs head shapes •Inverted conus vrtáčky2 Adobe Systems Cutting instruments – diamonds •Extra coarse – black • •Coarse – green • •Standard – blue or without any marker • •Fine - red • •Extra fine - yellow • •Ultrafine - white • • Adobe Systems Cutting instruments – diamonds head shape •Ball, pear, cylinder,taper,flame, torpedo, lens and others….. • • diambrouskytvary Adobe Systems Hazards with cutting instruments •Pulpal precautions •Soft tissue precautions •Eye precautions •Ear precautions •Inhalation precautions Adobe Systems Filling materials •Temporary • •Definitive, permanent Adobe Systems Temporary filling materials •Zinkoxidsulphate cement and one • component derivates • •Ziknoxidphosphate cement • •Zinkoxideugenol cement • •Polymer based materials • •Guttapercha • • Adobe Systems Permanent filling materials •Amalgam • • •Composites • • •Glasionomers • • Adobe Systems Amalgam Adobe Systems Amalgam • • • •Metal-like restorative material composed of •silver-tin-copper alloy and mercury. Adobe Systems Types of amalgam restorative materials •Low – Copper Amalgam (5% or less copper) •Composition – wt% • •Silver 63 - 70 % •Tin 26 – 28 % •Copper 2 - 5% •Zinc 0 - 2% Adobe Systems Types of amalgam restorative materials •High – Copper Amalgam (13% - 30%) •copper •Composition – wt% • •Silver 40 - 70 % •Tin 26 – 30 % •Copper 2 - 30% •Zinc 0 - 2% Adobe Systems Particles of the alloy üIrregulary shaped (filings - lathe cut) • üMicrosphers • üCombination of the two. ü • Adobe Systems Particles shape •High – Copper Amalgam •Microsphers of the same composition •(unicompositional) • •Mixture of irregular and spherical particles of •different or the same composition (admixed) • Adobe Systems Production of irregular particles •Metal ingrediences heated, protected from •oxidation, melted and poured into a mold to •form an ingot. •Phases of the alloy: (intermetallic •compounds) •Ag3Sn - g •Cu3Sn - e •Cu6Sn5 - h •Ag4Sn - b • Adobe Systems Production of irregular particles •Ingot cooled slowly • •Ingot heated at 400°C (6 – 8 hours) •(homogeneous distribution of Ag3Sn) • •Ingot cut on the lathe, particles passed trough a fine sieve •and ball milled to form the proper particle size. • •Aging of particles (60 - 100°C, 6 – 8 hours) • •Particle size: 60 – 120 mm in length • 10 – 70 mm in width • 10 – 35 mm in thickness • Adobe Systems Production of irregular particles •Molten alloy is spraying into water under •high pressue • • • Irregulary shaped high-copper particles Adobe Systems Production of spherical particles • •Molten alloy is spraying under •high pressue of inert gas through a fine •crack in a crucible into a large chamber • •Diameter of the spheres: 2 – 43mm • • • • Adobe Systems Amalgamation processes •Metal alloy is mixed with pure mercury Trituration Amalgamation processes Hg Sn Sn Sn Sn Sn Ag Ag Ag Ag Ag Cu Cu Cu Cu Cu Ag3Sn – g Cu3Sn – e Intermetallic compounds Amalgamation processes Sn Sn Sn Sn Sn Ag Ag Ag Ag Ag Cu Cu Cu Cu Cu Ag3Sn – g Cu3Sn – e Cu6Sn5 - h Sn7Hg – g2 Ag2Hg3 – g1 High copper amalgam – copper dissolved in mercury has high reaction afinity to tin that is also dissolved in mercury. It reacts with tin in gamma2 phase and eta phase comes into existence. The gamma 2 phase disappears. > Adobe Systems Setting of low copper amalgam • •Principle of setting is crystallization •Structure of the amalgam filling •Ag-Hg: gamma 1 •Sn-Hg: gamma 2 • •Gamma phase (Ag-Sn) does not dissolve • completely – remains in the structure These phases crystallized – become hard Adobe Systems Risks of the gamma 2 phase •Non stable • Tin is released due to electrogalvanism in oral cavity and mercury from this phase reacts with remaining gamma phase. •This is external electrochemical corrosion. • •Low copper amalgam has worse mechanical and corrosion resistance than high copper amalgam Adobe Systems High copper amalgam • Content of copper increased: 12 – 13% •(Less tin) • •Or up to 25% ( Less tin and silver) • •Better mechanical and corrosion resistance Amalgamation processes Sn Sn Sn Sn Sn Ag Ag Ag Ag Ag Cu Cu Cu Cu Cu Ag3Sn – g Cu3Sn – e Cu6Sn5 - h Sn7Hg – g2 Ag2Hg3 – g1 High copper amalgam g2 phase disappears or does not occur depending on the content of copper Gamma two disapears or it does not occur when content of copper is high Adobe Systems Amalgam - properties Adobe Systems Amalgam ØWear and pressure resistance (2mm thickness ast least)- brittleness ØEasy handling ØLow price ØThermal and electrical conductivity ØCorrosion ØBad aesthetics ØFlow (deformation of not completely set amalgam if the filling is loaded) ØCreep – completely set amalgam can be deformed due to bite forces. The filimng is principly hammered. Ø • Adobe Systems Biocompatibility • More than 160 years, more than 200 milions Ag fillings every year in USA. •Allergy rare •Precautions in children and in pregnancy. • •AMALGAM IS STILL A MATERIAL OF CHOICE Adobe Systems Toxicity * Organic compounds •Vapours, aerosol • Precautions •Ventilation •Rests of amalgam in water •Amalgam separators •Dangerous waste (180 110) Adobe Systems Amalgam indications •Posterior area •I. a II. class : moderate or large cavities, •V. class •Other factores for consideration •When oral hygiene is not excellent •When patient wants low cost filling. • Adobe Systems Indications and contraindications of amalgam •Indications • Moderate and large cavities in posterior area (class I., II. V) •Contraindications •Fillings in frontal area •Pregnancy, children till the age of 15 •Allergy •Other factores for consideration •When oral hygiene is not excellent •When patient wants low cost filling. • • Adobe Systems Mixing of amalgam Ø Hand mixing (obsolete) Ø ØPower driven trituration • • Amalgamators amalgADM lariovibro duomat podavani amalgam v prebytku cpani Cup Amalgam gun Condensor podavani Amalgam gun Crucible (cup) cpanistroj1 cpanistroj2 Power driven condensation handpiece condensor 1tridareal Adobe Systems Instruments ØPreparation instruments Ø ØFilling instruments Ø ØCarvers Ø ØBurnishers • Adobe Systems Instruments ØPreparation instruments - power driven Ø • preparačni nastroje vrtáčky2 Burs Diamonds Adobe Systems Instruments ØPreparation instruments - hand •Chisel • •Excavator Ø • sikmitka orezani okraju nosičamalgáámu Amalgam carrier Adobe Systems Amalgam carrier Cpátko_amalgámu_oboustranné_1 Adobe Systems Instruments ØFilling instruments condensors and spatulas Ø • • cpáátkko tyčinkov Condensor with flat front Adobe Systems Condensor with flat front Cpátko_oboustranné Adobe Systems Condensor and burnisher - spatula combined Hladítko_se_cpátkem_2 Adobe Systems • cpanistroj2 Power driven condensor Special handpiece Adobe Systems Burnisher - spatula Angular- trough edge trough face Hladítko_oboustranné Adobe Systems Burnisher – spatula, angular three face Hladítko_oboustranné_třikrát_lomené Adobe Systems Instruments ØBurnishers • Adobe Systems Ball condensor – used as a burnisher at most Cpátko_kuličkové_oboustranné