Tube & Screw InstructionsPREAT Corporation
Internal Hex Tube and Screw System
The internal Hex Tube and Screw is used for vertical screw retention of crowns and bridges, dentist-only removable fixed prosthesis, implant suprastructures, fixed complete (hybrid) dentures, and telescopic prostheses.
Easy to use. Prethreaded tubes for casting, soldering, or bonding to cast primary units.
Versatile. Multiple sizes of 1.20mm and 1.40mm diameter. Short and long available in each diameter. Same Hex used for
Pin Screw and Tube and Screw systems.
Accurate. End cutting bur provides for accurate sizing and finishing of cast collar.
Tube & Screw
The hex screw is a high fusing precious alloy. It can be shortened as needed, as long as the hex profile is maintained. The countersunk collar is a non-oxidizing, high fusing precious alloy. The conical hex screw perfectly fits the countersunk collar, efficiently distributing forces and creating a hygienic seal on the occlusal surface.
The sleeve is also a high fusing precious alloy, and the fixation screw holds the sleeve in place during casting, reducing the risk of molten alloy flowing into it.
Always use the largest and longest screw for the space available. The bonding technique for the tube is the most accurate method of incorporation.
Complete Tube and Screw Attachment
Includes Tube, countersunk Collar, Fixation screw, and final Hex screw.
Four different options:
- 1.2mm Short
- 1.2mm Long
- 1.4mm Short
- 1.4mm Long
The fixation screw can be destroyed at temperatures above 1400 °C and by excessive overheating of the casting alloy.
Primary Unit: incorporating the Tube
Please make sure to make a fresh mix of Ceka Site for each tube. Do not use the excess Ceka Site on the mixing pad, as its working time has expired.
The secondary unit is fabricated after trimming and polishing the primary unit. This involves inserting the countersunk collar with the screw, which has already been shortened as required. The countersunk collar is integrated in the wax pattern. A small groove should be cut around the junction between the wax and countersunk collar to prevent molten alloy flowing into the ring when casting. Invest, cast and polish the unit. Note: If the countersunk collar has been properly invested without bubbles, it should be adequately retained in the investment.
Finish the secondary structure, and attach to the primary structure with the Hex screw.
Removal of Screw Retained Prosthesis
The hex key is designed to ensure proper retention of the screws and safe handling intraorally. Note, retention of the screw on the hex key can be reduced while unscrewing. When the screw is almost completely undone, increase pressure to make sure it remains on the hex key. The hex key should also be secured with a cord in the drill hole provided. Cover the working area with a rubber dam to safeguard against aspiration.
The Tube and Screw are a holding device to maintain separate castings in a locked or fixed position. The Tube and Screw are not designed to correct movement or deficiency between two cast units.
Always keep the screw head out of occlusal contact.