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Over the years, one of the laboratory procedures that has created stress and required extra time has been investing and divesting partial dentures, especially because there was always the possibility of damaging the frame or breaking a clasp.
I've developed a technique that makes this process easier. I use a putty matrix made from Heraeus' Palapress vario, a rapid-cure acrylic for partial and full dentures. It has the technical properties of heatcuring acrylic, and color stability thanks to an ammon-free acceleration system. When cured, the material has less residual monomer than heat-cured acrylic (see graph below).
Palapress vario features a complex blend of cadmium-free, nontoxic pigments that are esthetic and seemingly disappear in the patient's mouth. It offers a great working time, flows into the smallest saddle areas bubble free, and is easy to polish and for the patient to keep clean.
For more information on the Palapress vario, contact Heraeus Kulzer at 800-431-1785 or visit www.heraeusdentalusa.com.
Step 8 Incorporate the lingual of the teeth and just below the teeth to catch the contour of the lingual waxup. The matrix ends on the lingual side just below the teeth, leaving a portion of the wax exposed which is the area into which you pour the acrylic.
Step 14 Mix the Palapress vario; the acrylic has great flow characteristics and, by capillary action, flows even to the smallest single anterior lateral flange with no air bubbles and no vents.
Step 15 Fill the cavity from either the mesial or distal of the opening, allowing the acrylic to flow into the mold and minimize trapped air. Once the matrix is full, immediately put it in the curing unit at 55oC with 30 lbs of pressure for 30 minutes and then recover the partial by removing the matrix. Remove the flash by grinding on the lingual and polish the appliance.
Step 6 Begin applying the putty at one end of the case, making sure you capture all the facial contours and festooning.
Step 11 Before placing the matrix with the teeth back on the model, don’t forget the separator (I recommend Aislar) or tin-foil substitute and then replace the frame.
Steps 12 & 13 Carefully place the matrix with the teeth back on the model then secure it with a rubber band. Be careful not to distort the matrix; use just enough tension to hold it in place.
Steps 3, 4 & 5 When you’re preparing to make the matrix, keep in mind that the end result will only be as accurate as the matrix. Select a firm silicone lab putty; CutterSil Putty Plus from Heraeus is excellent. Measure the hardener and mix with your hands.
Step 7 The matrix must cover the facial and occlusal surfaces of the teeth. Extend the matrix to the adjacent teeth to create an index to locate the matrix back to the model.
Step 10 Boil the wax from the model and teeth, and place the teeth in the matrix. Put just a dot of Super Glue® on an incisal edge or two cusp tips—one lingual and one buccal—to keep the teeth from shifting as the matrix is placed back on the model.
Steps 1 & 2 Wax the case in the usual manner. If you have a distal-free end, make sure you have some land area in the posterior for the matrix to rest on to ensure the occlusal dimension doesn’t change.
Step 9 Remove the matrix.
YOUR FINISHED PARTIAL
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