Preparation of cavities - basic rules L. Roubalíková Preparation of dental caries (cavity preparation) > Instrumental treatment that removes dental caries >The rest of the tooth must be restorable with filling materials >The rest of the tooth as well as the filling must be resistant against occlusal forces >The risk of secondary caries must be minimized Basic rules Acces to the cavity Preparation of cavity borders and extention for prevention - outlines Retention for the filling Resistance of the restored tooth as well asi the restoration (filling) Excavation of carious dentin Finishing of the walls Final control Basic rules Acces to the cavity Preparation through the hard dental tissues Removing of the undermined enamel (enamel that is not supported with dentin) Separation of teeth (wooden wedges) Separation or removing of gingiva (with temporary filling or surgical) Basic rules Preparation of cavity borders and extention for prevention Depends on Dental material Oral hygiene Precautions of secondary caries Basic rules Retention of the filling Precautions of its lost Macromechanical retention Micromchanical retention Chemical retention Basic rules Resistance of the restored tooth Against occlusal and other forces Depends on - Material - Individual occlusal forces Basic rules Excavation of carious dentin Necessary (risk of recurrent caries) Ball shaped (spheric) bur - slow speed (3000 rpm) or Excavator Basic rules Finishing of the walls Depends on the kind of material - Bevel or without bevel - Fine diamond bur Bas' Final control Direct or indirect view Good illumination Magnification Preparation • Hand Excavator, cleaver • Power driven Burs, diamonds Chisel -for enamel Cleaver Chisel for enamel Excavator . . . ■ ■ . v . _ 'Jjč-j'. .-\r .•.•.'.-.-' *&£&.'■ Instruments for cavity preparation Power driven (powered) instruments for cutting - Rotary instruments Comon design characteristics shank neck head lenka.roubalikova@tiscali.cz Cutting instruments - burs Steel Tungsten carbide Cutting instruments - burs head shapes Round (ball shaped) Round iEasy handling >Thermal and electrical conductivity > Corrosion > Bad aesthetics Trituration > Hand mixing (obsolete) > Power driven trituration Amalgama tors ti. :—■ _^ arm.. mm --------------- --------------------------------------------------1 Instruments > Preparation instruments > Filling instruments > Carvers > Burnishers Instruments Preparation instruments - power driven Burs Diamonds U=J Pear-shaped Slrai£hi 'ÍSSLNE Taps red ÍÍ9SUT& F£ 7-34 Basic 3jur h^jd s napr;-; Instruments > Preparation instruments - hand Chisel Excavator Amalgam gun Cfucible Amalgam carrier Amalgam carrier ■HÉ Instruments > Filling instruments condensors and spatulas Condensor -stamen ) o Condensor -stamen Condensor and burnisher - spatula combined i^^^^^^^^_. -■ Power driven condensor - stamen Special handpiece Burnisher - spatula Angular- trough edge trough face Burnisher-spatula, angular three face ^i"^^_^ ^ Instruments > Burnishers Ball condensor - used as a burnisher at most *" r , iŕ'imin- (li ■ Villi 111«^^^