Class II. – modifications for amalgam ⚫ Conventional preparation ⚫ Slot ⚫ Large cavities – replacement of the cusp (cusps), combination with the cavity on vestibular/oral surface Class II. 2 Origin: Proximal surface below the contact point Propagation of dental caries from the occlusal surface Occlusal cavity Proximal cavity MOD lroubal@med.muni.cz 5 lroubal@med.muni.cz 6 Cavosurface angle Slight reveres curve Clearence of the proximal surface lroubal@med.muni.cz 10 Matrix placement ➢ Matrix primarily is used when a proximal surface is to be restored The objectives: - Provide proper contact - Provide proper contour - Confine the restorative material - Reduce the amount of excess material lroubal@med.muni.cz 11 Matrices ➢ Ivory I retainer Ivory 1 ➢ Hawe Neos retainer Ivory 8 ➢ Tofelmire matrix and retainer lroubal@med.muni.cz 12 lroubal@med.muni.cz 13 lroubal@med.muni.cz 14 Wedges ➢ Wooden wedges - tighten the matrix band - compress the gingiva - separate the teeth lroubal@med.muni.cz 15 Wedging ➢ Slip the matrix band over the tooth )apical to the gingiva margin – 0,5, - 1 mm) ➢ Tighten the matrix, check it with probe ➢ Place a wedge ➢ Turn the retainer ¼ counterclockwise ➢ Contour the band 16 Amalgamators lroubal@med.muni.cz 17 Condensation of amalgam ⚫ Condensor – with the straight front ⚫ Power driven condensation How big should the front be? lroubal@med.muni.cz 18 lroubal@med.muni.cz 19 lroubal@med.muni.cz 20 lroubal@med.muni.cz 21 lroubal@med.muni.cz 22 lroubal@med.muni.cz 23 lroubal@med.muni.cz 24 lroubal@med.muni.cz 25 lroubal@med.muni.cz 26 Base ➢ Zinkoxidphosphate cement ➢ Zinkoxidkarboxylate cement ➢ Glass ionomer cement ➢ Zinkoxideugenol On pulpal walls only! lroubal@med.muni.cz 27 lroubal@med.muni.cz 28 The base must be hardened lroubal@med.muni.cz 29 Amalgam Retention lroubal@med.muni.cz 30 lroubal@med.muni.cz 31 lroubal@med.muni.cz 32 lroubal@med.muni.cz 33 Instruments ⚫ Preparation ⚫ Filling ⚫ Finishing and polishing lroubal@med.muni.cz 34 Cpátko tyčinkové lroubal@med.muni.cz 35 Ořezávač -Frahm lroubal@med.muni.cz 36 lroubal@med.muni.cz 37 Sapin lroubal@med.muni.cz 38 Discoid-cleoid lroubal@med.muni.cz 39 Amalgam carrier Retention – grooves in the proximal cavity Divergency of axial walls towards gingiva and Convergency - divergency towards proximal space. Autoretention Slot is a cavity that is open on occlusal surface. It is limited on the proximal ridge Slot preparation Slot for amalgam ⚫ Access to the caries lesion - through the enamel wall - breaking out of the enamel lamella - excavation of carious dentin lroubal@med.muni.cz 45 Pre op lroubal@med.muni.cz 46 Access to the cavity Slot for amalgam Autoretention - Grooves - Divergency towards gingiva - Convergency and divergency of axial walls in horizontal plane(towards proximal space) Slot for amalgam ⚫ Rule of the gingival wall -1 mm wide -90% angle towards the pulpal wall -outer line beveled if in enamel -horizontal groove Sedelmayer Sedelmayer J. Amalgám – zapomenuté řemeslo. Brno, 2000. Bažant V. Konservační zubní lékařství, SPN Praha,1962. Slot cavity ⚫ Limited on proximal ridge ⚫ Axial walls are divergent towards gingiva ⚫ The proximal box has a typical picture of fish tail ⚫ There are grooves: - One horizontal in gingival wall - Two vertical in axial walls Large defects ⚫ In vital teeth if the cusp has been undermined due to dental caries ⚫ Large defects in non vital teeth – amalgam overlays ⚫ Combination with the cavity on vestibular/oral surface Cusp has been removed The thickness of the filling 3 – 4 mm (at the cusp) Retention Grooves, pins, slots Parapulpal pins Intrapulpal posts (root canal posts) Retention in the endodontic cavity Large amalgam restoration - overlays ⚫ lroubal@med.muni.cz 58 Amalgam Exact work! lroubal@med.muni.cz 59 Basic modifications Rules for large restorations ⚫ Clear and sharp outlines – cavosurface margin Thickness of the amalgam (the cusp 3 – 4 mm) ⚫ Autoretention - Grooves - Pins, slots - Parapulpal pins - Intrapulpal posts – root canal posts Resistance – acc to general rules Composites - indication ⚫ Small – moderate cavities - Good level of oral hygiene - No heavy occlusal stress - Dry operating field Preparation for adhesive materials – composites ⚫ No extension for prevention (adhesion) ⚫ No grooves ⚫ No undercuts ⚫ Rounded box ⚫ Bevel the axial walls and the outer edge od the gingival wall ⚫ Small isolated cavities are possible Cavity for amalgam Cavity for composite Bevel on the gingival wall Preparation do not bevel!!! If out of enamel Bevel of enamel on axial walls Yes No Amalgam Composite material Monomer Light Polymerization Polymer Polymerization – light curing composites - Mode of polymerization Phases - Pre-gel - Gel-point - Post –gel phase Pre –gel Gel Post -gel Pre gel phase should be long – soft start 1 2 3 Placement of the material Correct 85 86 Matrices for composites in class II. ⚫ Matrix band + matrix retainer ⚫ Segmental matrix + separator Sedelmayer Alternative preparation – adhesive slot Tunnel preparation 1. Low caries risk 2. Proximal ridge without infrac 3. Good cooperation 4. Small caries lesion 1. Magnification(Loups or microscope) 2. Miniinstruments 3. Dezinffection 4. GIC in capsules or composite 5. BW post op Glassionomer and class II. ⚫ Temporary filling – first phase for the sandwich technique ⚫ Tunnel filling (preparation)