amalgam. When the amalgamator stops, remove the amalgam capsule for the amalgamator, open the capsule, and empty the mixed amalgam into the amalgam well. Use caution with the amalgam mix because any moisture contamination causes the finished restoration to expand. Load the amalgam into the amalgam carrier (fig. 4-39). Some dentists permit the assistant to dispense the amalgam into the cavity preparation. Other dentists prefer to have you pass the loaded amalgam carrier and dispense the amalgam themselves. In either case, you must pass the amalgam condenser to the dentist. The dentist uses the condenser to pack the amalgam firmly into all the areas of the prepared cavity. During the condensing procedure, the dentist indicates when a change of condensers is needed. As you gain experience, you will know wh en a change is needed by observing the stage of completion. The exchange of amalgam carrier and condensers continues until the cavity preparation is slightly overfilled. When the condenser is used for the last time, the dentist may use a burnisher and or an explorer on the restoration before removing the matrix band.

The dentist uses a burnisher to bring any excess mercury from the amalgam placed to the top of the restoration. Next the explorer is used to slightly contour the restoration between the tooth and the band before removal of the matrix and retainer. For dentists who choose to initially carve the occlusal anatomy into the restoration before removal of the matrix, have an amalgam carver ready to pass when you receive the explorer. You will also need to have the cotton forceps from amalgam well. or hemostat ready to pass when the dentist is ready to remove the wedge, retainer, and matrix band.

Figure 4-39. - Loading amalgam into the amalgam carrier

The dentist uses an interproximal carver to smooth the gingival margin of the amalgam restoration at the interproximal area. Only the excess amalgam is removed near the gingival margin to allow the proximal contact to be retained. The dentist continues carving the proximal surfaces to conform to the contour of the inter-proximal area of the tooth. The dentist uses another carver, such as the discoid-cleoid, to carve the primary grooves on the occlusal surface and remove excess amalgam. You may need to have another carver ready to pass to the dentist to carve the facial and lingual margins of the amalgam, if applicable. In addition to passing and receiving a variety of carvers to the dentist, you will need the high- volume evacuator (HVE) tip in your other hand to aspirate the shavings from the carving procedure at various times. When carving the amalgam restoration is completed, remove the rubber dam. Irrigate and aspirate the patient's mouth and check the occlusion of the new restoration for any needed adjustments.

Have the articulating paper ready for use by placing it into a hemostat or articulating paper holder. Pass this to the dentist to check the occlusion of the restoration. The articulating paper is placed in the teeth of the opposing quadrant and the patient is instructed to gently close the teeth together. If the patient closes the teeth together too suddenly or with too much pressure, the new amalgam restoration will fracture if it is too high. Have an amalgam carver ready to pass to the dentist to reduce any high spots on the amalgam restorations. The restoration is checked with the articulating paper and carved until the proper occlusion is obtained. Have a burnisher, such as a ball or ovoid, ready to pass to the dentist to burnish the amalgam restoration. When the restoration is completed, the oral cavity is irrigated and aspirated using the water syringe. Use the HVE to remove amalgam shavings resulting from the occlusal adjustment. Before dismissal, ensure the patient is given the postoperative instructions and understands them.

MERCURY CONTROL PROGRAM FOR DENTAL TREATMENT FACILITIES. - All dental personnel will follow BUMEDINST 6260.30 because of the health hazard potential of mercury. This instruction discusses control procedures for the handling and disposal of amalgam or mercury- contaminated items and is discussed in Volume I, Chapter 11, "Dental Safety and Equipment."