lenka.roubalikova@ti scali.cz 1 Classification acc. to Black  Class I. Pit and fissure caries lenka.roubalikova@ti scali.cz 2 Classification acc. to Black  Class II. Proximal surfaces in premolars and molars lenka.roubalikova@ti scali.cz 3 Classification acc. to Black  Class III. Proximal surfaces of incisors and canines without lost any part if incisal edge lenka.roubalikova@ti scali.cz 4 Classification acc. to Black  Class IV. Proximal surfaces of incisors and canines with lost an incisal ridge lenka.roubalikova@ti scali.cz 5 Classification acc. to Black  Class V. cervical lesions lenka.roubalikova@ti scali.cz 6 Preparation of cavities Basic rules Access to the cavity Outlines – cavosurface margin (extention for prevention) Principles of retention Principles of resistance Excavation of carious dentin Preparation of borders – finishing Control lenka.roubalikova@ti scali.cz 7 Protection of dentin wound  Dentin wound should be covered – protection of dental pulp against irritation Physicial -thermal -osmotic Chemical Combination lenka.roubalikova@ti scali.cz 8 Protection of dentin wound Isolation Filling (small cavities) Base (moderate – large cavities- depth 2mm and more approx.) Adhesive systems ( composite materials) lenka.roubalikova@ti scali.cz 9 Filling  Filling replaces lost hard dental tissue anatomically and functionally  Always different properties in comparison to hard dental tissues. lenka.roubalikova@ti scali.cz 10 Base is made usually of zinkoxidphosphate cement It is placed only on pulpal wall Preparation of the cavity I.st class acc. to Black  Cavities in fissures and pits  (Occlusal surfaces of premolars and molars and in f. coeca) F. Coeca: buccal surfaces of lower molars, Palatal surfaces of lower molars, palatal surfaces of upper incisors (mostly lateral) Morphology of fissures Biofilm Caries All pit and fissure restorations (fillings) They are assigned in to three groups. R. on occlusal surface of premolars and molars R. in foramina coeca – usually on occlusal two thirds of the facial and lingual surfaces of molars. R.on lingual surface of maxillary incisors. Materials: Amalgam, composite. Amalgam: Pertinent material qualities and propeties Strength Longevity Easy of use Clinically proven sucess Access to the cavity  From the occlusal surface using the fissure bur (or diamond burs, see below). Cavosurface margin  Ideal outline includes all occlusal pits and fissures. If crista transversa (1st lower premolar)or obliqua (1st and 2nd upper molar)are not affected, it is strongly recommended no to prepare them. Mandibulary 7 Mandibulary 6 vestibulary orally MB cusp Transverse ridge Third molars - variable ½ distancw between the botom of the fissure and the cusp Retention  Box – undercat (1,5 – 2 mm deep). Box Undercut The cavity with undercuts at the bottom Resistance Depth 1,5 – 2 mm The enamel is always supported with The cavosurface margin till ½ distance of the bottom of the fissure and the cusp No sharp edges Excavation of carious dentin  Round burs : 3000/min  Excavators Nízké Orientation of the pulpal wall Protection of dentin wound Finishing Fine diamonds Final check Good illumination, dry field, magnification. Direct and /or indirect view Oblique ridge 6 7 8 6 7 8 Molars Foramen caecum: Preparation is limited on carious lesion The bottom is located in dentin Undercuts Finishing of cavity borders If the enamel is undermined occlusally – extention on occlusal surface Preparation with preservation of the transverse ridge Premolars Crista transversa Lower P1 Amalgam Metal-like restorative material composed of silver-tin-copper alloy and mercury. 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% Types of amalgam restorative materials High – Copper Amalgam (13% - 30%) copper Composition – wt% Silver 52 - 70 % Tin 14 %– and less Copper 12 - 30% Zinc 0 - 2% Particles of the alloy  Irregulary shaped (filings - lathe cut)  Microsphers  Combination of the two. Particles shape High – Copper Amalgam Microsphers of the same composition (unicompositional) Mixture of irregular and spherical particles of different or the same composition (admixed) 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 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 Production of irregular particles Molten alloy is spraying into water under high pressue Irregulary shaped highcopper particles 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 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 – gamma Cu3Sn – epsilon 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 These phases crystallized 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 that has not been dissolved yet.  This is external electrochemical corrosion. Low copper amalgam has worse mechanical and corrosion resistance than high copper 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 – gamma Cu3Sn – epsilon Cu6Sn5 – eta Sn7Hg – gamma2 Ag2Hg3 – gamma1 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. Amalgam - properties Amalgam  Wear and pressure resistance (2mm thickness ast least)- brittleness  Easy handling  Low price  Thermal and electrical conductivity  Corrosion  Bad aesthetics  Creep  Flow 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 Toxicity Organic compounds Vapours, aerosol Precautions  Ventilation  Rests of amalgam in water  Amalgam separators  Dangerous waste (180 110) 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 Mixing of amalgam  Hand mixing (obsolete)  Power driven trituration Amalgamators Cup Amalgam gun Condensor Amalgam gun Crucible (cup) Power driven condensation handpiece condensor Instruments  Preparation instruments  Filling instruments  Carvers  Burnishers Instruments  Preparation instruments - power driven Burs Diamonds Instruments  Preparation instruments - hand Chisel Excavator Amalgam carrier Amalgam carrier Instruments  Filling instruments condensors and spatulas Condensor with flat front Condensor with flat front Condensor and burnisher - spatula combined Power driven condensor Special handpiece Burnisher - spatula Angular- trough edge trough face Burnisher – spatula, angular three face Instruments  Burnishers Ball condensor – used as a burnisher