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#19 Anatomy 3 facial cusps (Mesiobuccal, distobuccal, distal) 2 lingual cusps (Mesiolingual, Distolingal) 2 buccal grooves (MB and DB) 3 Fossae (M, D, C) 2 triangular ridges Buccal cusps even in size and height Distal cusp higher than marginal ridge of #18 narrower than other cusps Ginigval floor extends to facial Build Up armamentarium contra angle toffelmire and extended matrix band anatomical burnisher Condensing technique large area many cavosurfaces overfill Marginal ridges relatively the same height in the same quadrant Pins* The dentist may place only the retention pin, nothing else* help retain the amalgam into the prep when one or more cusps have been lost. are placed in holes that have been drilled entirely within dentin, not enamel one pin/ cusp missing* Pin depth 2 mm in dentin with 2 mm exposed Pin condensing must be condensed around as it is layered Types of pins screw type cemented friction lock Screw threaded so it can be screwed into the hole hole is slightly smaller than screw Cemented Pin small than the hole in order for room for cement Friction lock slightly larger than hole and must be tapped into the hole Preperation shape missing DB cusp and groove and all of distal cusp Rubber dam for #19 one behind, two in front rubber wedge on mesial of #21 Benefit of contra-angled retainer can be placed on lingual so the smooth part of the matrix can be adapted to the buccal also can be angled up over the mand. ant. teeth Wedges for #19 placed facially for better adaptation pg 117 pic* contoured #2 matrix band Criteria for matrix and wedge retainer is placed ligually, slots and smaller opending toward ginigva occlusal .5-1.5 and gingival extension .5-1.0 mm secure and stable wedge adapts band snugly without entrapment proximal contact is visual with adjacent tooth Condensing pattern most inaccesible area first carry two increments to one area at one time using both ends of the carrier condense toward the proximal contact, but not too much Anatomy goals form the central groove where you can rest on intact cusp contours and form the missing cusps last Never.. permit the amalgam to entirely conver the unprepared tooth cusps Missing cusps formed like a mountain, MB can be used as a guide when ironing the other cusps Marginal ridges form the height first form mesial first marginal ridges should be concave at first Immediately evaluate margins with the hollenback Proximal contacts resist without fraying occlusal to middle 1/3, never gingival continous embrasures Occlusion not grossly out of occlusion, should be within curve of spee Advantages of finishing and polishing once hardened (24 hours) they ma be perfected (finished) and smoothed (polished) two seperate steps Finishing perfecting Polishing smoothing Benefits of finishing and polishing improves corrosion resistance reduces marginal breakdown makes restoration easier to keep clean Polishing* relatively low speed with intermittant strokes under moist conditions to achieve luster Finishing burs used for finishing amalgam different than cutting because of more, smaller, cutting ridges Flutes small, cutting ridges on finishing burs reduces potential for cutting away enamel Basic set-up flame round (large and small) football or pear Finishing bur characteristics* made from steel, prone to rust smaller flutes than prep bur have fine mulitflutes have more flutes per bur than a cavity prep bur Super-Greenie cup and point light green with yellow ring finest grit used last Green cup and point are greeen medium grit Brownie cup and point* brown coarse grit used first Green stone gross excess White stone perfecting submarginal areas <.2mm removes enamel never remove cementum--->sensitivity Ideal finished amalgam perfectly reproduced anatomy and even occlusion margins are flush and a surface that is smooth and shiny without lumps and bumps Finishing use of instruments or burs to perfect the shape of the amalgam as needed margins, anatomy, occlusion, contour Finishing margins either too much amalgam or too little amalgam Overextension bumps up from tooth to amalgam Flash extended beyond the margins Flame smooth convex surface used as a hollenback follow contour do not remove tooth Slow speed handpiece finishing burs forward Finishing discs used for removing flash on class V and buccal or lingual class II one abrasive side one non abasive side Abrasive side adapted to the tooth grazing strokes coarse to fine Coarse discs darker finishing Fine discs polising Rinse between each type of disc to remove scratches Gold Knife overextensions can be removed shaving similar to hollenback Gold File rubbing motion Submarginal areas bumps from restoration to tooth removed with finishing stone (white) less than .2 mm do not expose dentinal tubules Burnished facets marks that are shiner than the rest of the amalgam and are flattened like the facet of a diamond high occlusion don not flatten but contour or deepen fossa Temperature * >140 can cause pulpitis, bring Hg to surface-->suceptibility to corrosion and dull cloudy surface Pear shaped/Football shaped concave surfaces and ridges deepen fossae similar to cleoid Small round accentuate grooves After finishing all margins flush anatomy is defined and reasonable smoothness Polishing* process of removing minute scratches and producing a shiny surface with no visible surface pits Benefits of polishing easier to keep clean Rubber cups, points, discs used to impregnate the abrasives for polishing brownies, greenies, super greenies\ contour determines Abrasives coarse to fine rinse between Slow speed polishing handpiece prevents rubber disintegration Polishing strokes one off do not stay in one spot Points fossae Cups smooth surfaces Discs embrasures