2. Instrument of cavity preparation
• High speed small round bur,fissure bur,inverted
cone bur.(carbide or diamond)
• Low speed round bur.(carbide)
• Hand cutting instrument
3. Step of amalgam
cavity preparation
• In shallow cavity,outline form design should be
considered first.
• In deep cavity,convinience form and remove of
deepest part of carious dentin must perform
before any other step of cavity prepared.
4. Cavity preparation(I)
• Cavity depth 1.5 mm or beneath DEJ 0.2 mm.
• Isthmus width equal 1/3-1/4 B-L cusp width.
• Cavity width should less than ½ of B-L cusp
width.
• Buccal-lingual converge and mesial-distal diverge.
• Marginal ridge should preserve of 1.6 mm.
• Pulpal wall parallel to occlusal plane.
• Not involved oblique and transverse ridge, if it is
unnecessary.
5.
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11.
12.
13. Criteria of carious dentin removed
• Remove unminerized dentin with excavater or
low speed round bur.
• Tiny white powder without stagnation on bur
surface.
• Light reflect over dentin surface.
14.
15.
16.
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18.
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20.
21.
22. Cavity preparation(II)
• Trunket cone in proximal box.
• In Class II cavity , proximal clearance 0.2 mm,
gingival clearance 0.5 mm. Reverse curve in
buccal surface.
• Axiopulpal line angle should be rounded or
bevel, gingival line angle beveled.
• Gingival wall width should be 0.8-1.2 mm.
