Full metal crown lost wax technique

Step 1: Pouring the impression. a-Mix yellow stone with adequate amount of water in order to obtain the desirable consistency. b-Yellow stone is poured on an already made A-silicone impression (target: prepared tooth). c-Vibrator is used in order to get the details, and eliminate air bubbles. Step 2: Pins placement. a-The pin is placed at the center of the prepared tooth from the bottom, adequate depth in stone is required. b-2 other pins: one mesial, and other distal are present for stability of the stone (once placed on gypsum), in addition to a pin on the other side of the stone. c-All the pins should be parallel. d-Separating medium (soap solution + water/Vaseline) are placed on the stone. Step 3: Pouring gypsum in base former, and cast placement. a-Powder and water should be mixed to obtain adequate consistency (cream like). b-Shake the base former, to eliminate air bubbles. c-Place the cast (with pins) on the base former containing the gypsum. d-Trim the final product. Step 4: Splitting. a-Using a suitable saw, then cut proximally to the prepared tooth. b-cutting should be parallel, with no distortion of finish line on either sides. Step 5: Ditching. a-Using appropriate bur, start ditching. b-Do not touch the finish line, the main target is to expose it, and smoothening the margin. Step 6: Waxing the prepared tooth. a-Place separating medium on the die (e.g. Vaseline). b-Gently, place the wax on the tooth, and start anatomy building. c-Carving the wax for esthetic, and anatomic considerations. Step 7: Sprue placement. a-The main purpose of the sprue is allowing metal passage. b-Place the sprue, and cover it with wax in order to sustain it in place. Step 8: Placement in investing ring. a-Place the sprue attached to the wax, to a rubbery crucible former. b-Placement of the investing ring before pouring the investment material is crucial. Step 9: Add investment material. a-Special type of gypsum is poured slowly within the ring containing the wax, and sprue. Step 10: Burnout. a-This step is important in order to melt the wax, and remove it. b-Centrifugal casting machine: used to melt the wax, and push it in the left cavity (temperature of metal reaches 1400 degree Celsius). c-Casting: pouring the metal in the left cavity after burnout. Step 11: Finishing and polishing the crown. a-Use appropriate burs, and discs for finishing, and rubber wheels for polishing.