Press-i-Dent Pressable Ceramics

Transcription

1 Press-i-Dent Pressable Ceramics User Manual Aurident, Inc. PO Box 7200 Fullerton, CA (800)

2 Press-i-Dent Pressable Ceramics: Press-i-Dent Pressable Ceramic is a high strength leucite glass ceramic for creating all-ceramic single crowns, veneers, onlays and inlays. The flexural strength as measured according to ISO standards 6872 and 9693 is greater than 120 MPa.. Press-i-Dent Pressable Ceramic pellets are available in the shades outlined in Table 1: Shade California White TABLE 1 Equivalent Press-i-Dent Designation PRE009 Press-i-Dent Veneers A00 PRE010 PRE044 A0 PRE011 PRE045 A1 A2 A3 PRE012 PRE013 PRE014 A3.5 PRE015 B00 PRE016 PRE048 B0 PRE017 PRE049 B1 B2 C1 C2 D3 D2 PRE018 PRE019 PRE020 PRE021 PRE022 PRE023 Each pellet has a single shade and allows the facile fabrication of restorations by the staining technique, three-quarter build-up or glazing directly. The technique selected will depend upon the application and degree of aesthetics required. Press-i-Dent Pressable Ceramics are designed to work exclusively with Radiance Porcelain for optimum aesthetics. The large difference between the Radiance Porcelain baking temperature and the pressing temperature of Press-i-Dent assures that critical margins and anatomy do not distort. 2.

3 Press-i-Dent Pressable Ceramics Preparation: Press-i-Dent Pressable Ceramics can be used for the fabrication of inlays, onlays, veneers and full crowns. As with all pressable ceramic systems, certain precautions are necessary to assure proper copings: Waxes used should be ash free and residue free to avoid voids or incomplete pressings All units must be prepared with rounded incisal or occlusal angles All angles must be rounded with no square, box or sharp edges A die spacer of microns should be used prior to waxup for cementation relief and should be painted to within 1 mm of the prepared shoulder margin Inlays and onlays should have a minimum of 2 mm reduction in the central fossa area (Figures 1 and 2) Full crowns should have a 1 mm reduction (Figures 1 and 2) Veneers should have a minimum of 0.8 mm reduction Figure 1 Figure 2 In creating the wax model the general guidelines for a full coverage unit is a 2/3 reduced version of the full contour to maintain the ideal 2/3 core to 1/3 overlay ratio. 3.

4 Spruing: Figure 3 Adherence to the following procedure is essential to achieve fully dense copings that retain fine detail and margins. 1. A 6 gauge sprue provides the optimum flow during pressing. 2. The length of the sprue should be approximately 6 mm (Figures 3 and 4). The entire pattern (sprue + restoration) should be no longer than 16 mm in height. 3. Sprues are attached to the thickest cross sectional area of the restoration to assure optimum flow. When pressing a single unit, the inclusion of a phantom sprue may help in achieving a uniform pressing. Figure 4 4. The wax unit with wax rod attached is weighed. One Press-i-Dent ingot is required for a wax weight of 0.6 g or less. For the maximum weight of 1.4 g of wax, two ingots of Press-i-Dent are needed. [Note: in weighing the wax pattern: a) the weight of the ring base with the wax in the opening is recorded, b) the wax patterns to be pressed to the base are attached and weighed, and c) the difference in weight between the two values is the weight of wax used.] 5. When attaching the sprue to the waxed unit, any right angles at the attached areas must be avoided. All attachments must be well-rounded to avoid flow stoppage or creating high stress areas that could result in a fracture. The design and attachment of sprues to the wax pattern must provide a direct path of flow for the ceramic material. 6. When spruing multiple units, the sprues cannot be longer than 6 mm and the angle between patterns around 60 degrees as shown in Figure 5. The thickest cross-sectional area should face the outside of the ring when investing. All wax patters should be at the same height with at least 3 mm distance between individual wax patterns. When investing, the wax patterns must be 6-7 mm from the edge of the ring. Figure 5 4.

5 Investing: A high quality, thermally and mechanically stable investment designed for pressable ceramics such as Aur-i-Vest Investment should be used to assure adequate pressings. Investing can be done using either a standard ring or paper ring formers. Maintaining consistency in mixing procedures and following the published ratios for the special liquid and water are essential for assuring consistent pressed copings. The following precautions should be taken. 1. All utensils and mixing bowls for preparing the investment must be clean and dry. Dirty or highly worn mixing bowls and blades may result in investment failure. 2. The special liquid, water and powder should be at room temperature. If the liquids are cold, the investment bench set time should be extended for several minutes to assure all chemical reactions are complete. 3. The total volume of special liquid and water must be kept constant at a value specified in manufacture s instructions. For a tighter fit, the amount of special liquid is increased and amount of water is reduced by a corresponding amount the so that the total volume remains the same. For a looser fit, the amount of the special liquid is decreased and the amount of water is increased by a corresponding amount so that the total volume remains the same as specified in the instructions. 4. Prior to investing, the height of the wax pattern in the mold is measured or identified by either marking the height with an extra plunger or by placing a small button of wax on the interior surface of the investment mold at the height of the coping (Figure 6). 5. Prior to mixing investment in the mixer, the mixture of special liquid and water with the investment powder is fully blended using a clean spatula for approximately seconds. The investment mixture is mechanically mixed under vacuum for 60 seconds at rpm (Figure 7) and is poured over the wax pattern(s) (Figure 8). The extremely fluid mixture does not require any vibration for pouring. Figure 6 Figure 7 Figure 8 5.

6 6. The mold is filled approximately 16 mm above the wax patterns and any glaze on the surface of the mold is scraped to allow any gases, which are formed, to escape. 7. The investment mold is allowed to bench-set for 15 to 20 minutes before removing from the ring and placing in the burnout furnace. Burnout: Aur-i-Vest Investment can be placed in a burnout furnace at the burnout temperature. After removing the investment from the mold, the investment and pressing plunger are transferred into the burnout furnace at 850 o C (1560 o F) for 30 minutes for small rings and 60 minutes for large rings such as 300 g molds. Press-i-Dent pellets cannot be preheated in the burnout furnace! Note: For large wax or plastic patterns and sprues, it is advisable that the burnout be performed in stages to prevent unnecessary internal stresses or excessive gas buildup that could possibly lead to investment cracking. A suggested heating schedule is 20 minutes at 425 o C (800 o F) and ramping up the temperature to 850 o C (1560 o F) in approximately 100 degree increments. Pressing: Pressing furnaces must be properly calibrated so that the temperature will be maintained between 1100 o C 1130 o C (2012 o F 2070 o F) to assure proper processing conditions and dense pressings. Furnaces out of calibration may require increasing or decreasing the temperature from that shown on the readout to achieve proper pressing conditions. Furnaces should be calibrated frequently to maintain consistency. After burnout, the investment is removed and placed on an insulated surface to avoid thermal shock that could cause in cracking. The room temperature Press-i-Dent pellet is placed in the ring and the heated plunger is positioned on top. The assembled ring is immediately placed in the pressing furnace which has been programmed for the pressing cycle shown in Table 2. : Table 2 Oven Entry Temperature Vacuum Start Heat Rate (deg/min) Pressing Temperature Hold Time Pressing Time Air Pressure OPC, Whipmix, Ceramco, Ney 700 o C 1290 o F 550 o C 1020 o F 60 o C 140 o F o C o F 16 Min 7 Min 4.25 Bar EP o C 1290 o F 550 o C 1020 o F 60 o C 140 o F 1150 o C 2100 o F 20 Min N/A 4.25 Bar 6.

7 Devesting and Seating: After the ring has cooled to room temperature, the coping is devested as follows: 1. The depth of the restoration is measured with the plunger (Figures 6 and 9) or identified from the indentation left by the wax button used on the inner surface of the ring (Figure 10 note the mark on the ring). This permits marking the investment so that the excess material may be easily removed with a diamond disk. A sharp diamond disk is used to section the pressings as shown in Figures 10 and 11. Figure 9 Figure 10 Figure The coping is removed by sandblasting with clean and unused 50-micron glass beads with the pressure end blowing the beads at the sprue base at a pressure of 2 bars. Best results are obtained by maintaining the blast tip at a 45 degree angle to the pressed surface. Interior portions of the coping are sandblasted at a reduced pressure. Extra caution must be used when sandblasting around the margins. 3. Once the coping has been removed from the investment, the quality of the pressing is inspected (Figure 12) and the sprue removed with a new or sharp diamond disc (Figure 13). To avoid overheating and potential cracking, minimal force or pressure is applied. Figure 12 Figure After removing the sprue, the restoration is seated on die or model to check fit (Figure 14). Indicator paste or spay is used to spot areas to relieve and adjust contacts. 5. The surfaces are thoroughly cleaned before any ceramic application, staining or glazing. Figure 14 7.

8 Porcelain Layering: Following devesting and seating of the pressed coping, the restoration is cutback to allow room for porcelain layering. During the cutback, it is critical to avoid undercuts into the pressed coping. The maximum porcelain thickness should not exceed 30% of the total thickness of the restoration. Various views of the techniques used for incisal cutback are shown in Figures 15 through 18. Figure 15 Figure 16 Figure 17 Figure 18 Outstanding restorations are possible with a single application of Radiance Porcelain. However, even greater aesthetics are achievable with multiple bakes in the buildup process. This allows for greater occlusal definition and outstanding translucency. When followed by glazing or polishing with Matrix Diamond Polishing Compound, lifelike restorations are possible in minimal time. Techniques used for a three-quarters buildup are: 1. Cut back to the desired amount (see Figures 15 through 18). To avoid overheating and potential cracking, apply minimal force or pressure during the cutback. 2. Porcelain is applied to the incisal third of the pressed material (Figure 19) and baked using the processing conditions outlined in the Radiance Manual. 3. The coping is shaped and contoured, if necessary, and prepared for staining or glazing. Figure 19 Figure If staining and/or glazing are required, the conditions summarized in Radiance Manual are used. In rare instances when the underlying dentin requires even greater opacity than the pressable alone, a full buildup is possible with the application of Radiance Porcelain s opaqueous dentins. The temperature differences between the pressing temperature of Press-i-Dent Pressable Ceramic and Radiance Porcelain s opaque will assure that the coping does not distort or loose chroma and hue. Instructions for the application of opaque and the subsequent layering techniques are found in the Radiance Manual. 8.

9 Staining Technique: The individual shades of Press-i-Dent Pressable Ceramics permits use of the staining technique for the creation of restorations. The collection of stains and unique dentin modifiers of Radiance Porcelain allow creation of natural looking restorations with minimal effort. The dentin modifiers consist of nanosized particles in a slurry resulting in multiple advantages including: Creating higher chroma for better coverage of underlying dentin, Generating anatomical features without excessive grinding of thin veneers, and Achieving intermediate shades. With the staining technique the following steps are used: 1. Stains are applied as desired to achieve the correct shade and stain requirements. Radiance Porcelain s unique dentin modifiers may be used to add anatomy or to darken specific areas such as near the margins. 2. Bake conditions are found in the Radiance Manual. For the dentin modifier the dentin bake conditions listed in the Radiance Manual are used while the stains conditions are processed similarly to the glaze conditions. 3. Glaze bake conditions are found in the Radiance Manual. For higher gloss either a second glaze bake or porcelain polish with Matrix Diamond Porcelain Polishing Compound may be used. 9.