Line dentin with adequate base material (zinc phosphate cement or GIC) Caries removal
Matrix Band Apply matrix band Apply wedge from palatal side Burnish contact area
Review cavity The cavity must be checked for the followings before manipulation of amalgam Adequate self-retention. Proper resistance. CSA 90 . No caries, debris or moisture. Pulp is protected with cavity varnish, linear or base material depending on the cavity depth. Proper matrix is fitted.
Restoration Transfer amalgam to cavity in increments Start with proximal box
Restoration Condense amalgam thoroughly Use largest possible plugger
Restoration Overfill the cavity Separate amalgam from the matrix with a probe
Restoration Carve with half hollenbach carver Carve from tooth to filing following the margins Don’t over carve
Finishing The patient is then instructed not to use this side for the next 24 hours to avoid cracking or fracturing of the restoration. Also the patient should be advised to come after 24 hours for finishing and polishing of amalgam. Why? After 24 hours of carving to avoid disturbing crystallization of amalgam.
Finishing and polishing Aims: 1. Removal of any premature contact, marginal flashes or marginal over hangs. 2. Provide a lustrous homogenous amalgam surface. Advantages: 1. Increases corrosion resistance. 2. Decreases bacterial plaque retention and liability to recurrent caries. 3. Minimizes gingival irritation. 4. Improves strength of amalgam, as it removes the surface irregularities that act as stress concentration areas.
Finishing and polishing Technique: Finishing: 1. Using finishing bur in a direction from the tooth to restoration. 2. Using sandpaper discs for accessible surface.
Finishing and polishing Technique: Polishing: 1. Using pumice with brush or rubber cup. 2. Avoid heat generation, as it will lead to attraction of Hg to the surface resulting in: a) Weakening of the surface. b) Weakening of the bulk due to the formed porosity.
Matrix Bands Matrix: That which contains and gives shape and form to anything. Dental matrix: A piece of metal or non-metal, which gives form and support to the restoration during packing and hardening. Used only with direct restorative materials, which are packed into the cavity in the plastic form.
Function of matrix Serves as temporary wall or walls during condensation of plastic materials packed into compound or complex cavities. Gives form and shape to the restoration especially in contact area. Maintains this form of the restoration until it hardens. Prevents gingival marginal overhangs.
The matrix band should be properly supported with a wedge to provide adaptation of the band on the gingival floor and prevents marginal overhangs. Wooden wedges
The cavity should be properly matriced and wedged before manipulation of amalgam.