Class V. Cavity Preparation Characteristic defects Anatomical x Clinical crown Anatomical x clinical crown • Anatomical crown - cementům- enamel junction • Clinical crown - gingival border anatomical x clinical crown Cervical area • Predictable dirty place • Nearness of gingiva - possibility of its injury, bleeding, inflammation • Flow of the sulcular liquid 1 ^ Difficulties with the maintenance of the dry field • Specific ordering of the hard dental tissues 84 Ordering of the dental tissues Enamel Dentin Cementům Periodontium On the surface can be Enamel Cementům Dentin Risk of opening of the pulp chamber Access to the cavity • Elimination od the undermined enamel - Burs or diamonds (pear), tapered fissure bur • Separation of the gingiva- temporary filling guttapercha, fermit, clip, zinkoxidsulfate cement, cavit, provimat). • Ablation of ingrown gingiva - surgical (scalpel, laser, high frequency current) V.CIass Amalgam • Posterior area Determination of cavity borders (outlines) and extention for prevention We do not follow Black's rules exactly! Gingival: axial dephth of 0,5 mm inside the DEJ. Extention of the preparation incisally, gingivally, mesially and distally untill the cavosurface margins are positioned in sound dental structure. Total dephth: 1 - 1.25 mm. If on root surface -0,75 mm Incisal border Mesial Distal border Gingival border Retention Box 0,75 - 1,25 mm deep, undercuts, coves (larger cavities) Mesial Wail Axial Wal Resistance Elastic deformation during the biting Excavation of carious dentin Round bur Excavator Finishing of cavity borders Fine diamond bur of a chisel ) \ / Filling • Portion of amalgam are condensed using a condensor (stamen) and finished using a spatula or a carver. Class five - composite > Aesthetic reasons Contraindication of composites >Bad hagiene >Subgingival cavities >Root caries (outside of enamel) Access to the cavity • Elimination od the undermined enamel - Burs or diamonds (pear), tapered fissure bur • Separation of the gingiva- temporary filling guttapercha, fermit, clip, zinkoxidsulfate cement, cavit, provimat). • Ablation of ingrown gingiva - surgical (scalpel, laser, high frequency current) Composite must not be subgingival!!!! Determination of cavity borders outilines Cavity is limited on the caries defect only -no extention!!!! The depth usually 1 mm Retention > Micromechanical retention Enamel: Retentive border -1-2 mm wide and the angle 45° Cementům: only finishing with the fine diamond bur. Retention Retentive border: - removing of the aprismatic enamel - better condition for micromechanical retention - better aesthetics Retention Acid etching (phosphoric acid): 30 s dentin, 30 s enamel Rinsing (washing off) 30s Priming, bonding, light curing. Filling Spatula Matrix - Polyester strip, wooden wedges - Special cervical matrix Matrix Anatomical form Class five - glasionomer • Cavity outside of enamel Properties > Chemical fixation to tooth structure > Fluoride release > Favorable thermal expansion > Aceptable aesthetics Determination of cavity borders Cavity is limited on the caries defect only -no extention!!!! The depth usually 1 mm Retention > Box > Chemical Finishing öl Fine diamond bur cavity borders > Conditioner 20 s >Washing off >Wet cavity > Filling material > Matrix >Varnish ŕ M ^< Class V. - Sandwich principle Base of galsionomer - replace of the lost dentin Thin layer of composite - replace of the lost enamel Composite Base Bond: GIC - Tooth Chemical Composite - Tooth Micromechamcal Composite - GIC Micromechamcal