3M ESPE manual Injecting the Wax Pattern

Injecting the Wax Pattern

At the proper temperature, the wax will flow easily and be clear. If it is cloudy, it is too cool. If you hear it cracking in the pot, it is too hot.

When using the wax injector for the first time, melt 8–10 Celara™ Wax rods in the injector, and bleed the air out of the pump by pumping 4 or 5 times until wax begins to come out. Going forward, add 1–2 rods of wax per arch being fabricated.

Lubricate the stone cast with an appropriate model release agent. DO NOT FORGET TO LUBRICATE THE STONE CAST. The wax will stick to the stone if separating agent is not used.

Secure the container tightly together with a rubber band. Test the wax injector— PUMP SLOWLY— to make sure the wax is flowing. Prior to injecting the wax, make sure the alginate is dry and free of excess moisture. The alginate can be carefully dried with air immediately prior to injecting. Excessive moisture, especially in the anterior teeth, will cause the incisal edges to be misrepresented in the wax pattern. Carefully place the inlet sprue hole over the inlet of the wax injector and pump very slowly until the wax extrudes through the exit sprue(s).

In the case of the mandibular denture, the wax may extrude through one exit hole first. Place your finger over this exit hole and force the wax through the second hole. This will assure a complete pattern.

DO NOT REMOVE THE CONTAINER IMMEDIATELY. Keep the container on the inlet of the injector long enough for the wax to solidify in the inlet sprue hole. This will prevent the wax from running out when the container is lifted off (Figure 18). If the wax runs out, this will create voids in the “distal” end of the wax pattern.

Immediately place the container in a cold water bath to allow the wax to adequately harden—approximately 5 minutes. It is important for the wax to harden completely while securely on the cast, as this will ensure an accurate fit at try-in.

After the wax hardens, open the container and trim the wax pattern on the cast.

Occasionally, the wax pattern will come off the cast and it will be in the alginate. If this occurs, cut through the sprue before removing the wax from the alginate.

The Celara wax pattern is a replica of the denture over the cast. The wax is a special formulation which is rigid enough to obtain records in the mouth without distorting. If the wax pattern breaks or distorts upon removal from the cast, it usually means there are significant undercuts in the cast. If the wax pattern breaks or distorts, check the cast for undercuts and block them out with soft utility wax and re-inject a new wax pattern.

Figure 18

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