Sequencing platinum foil matrix removal in postceramic soldering of the collarless veneered retainer

Postceramic soldering of collarless veneered retainers in which the porcelain margins were formed with a platinum foil matrix technique was investigated. The purpose of the study was to determine if removing the platinum foil matrix before or after indexing and soldering procedures would affect the porcelain margin integrity in fixed partial dentures. Prostheses were fabricated on a nickel-chromium laboratory model using both sequences. Six test cycles were performed. Each cycle included one soldering with matrix support and one without the matrix, for a total of 12 solderings. The fixed partial dentures were compared for degree of marginal seating with a measuring microscope and for configuration changes at the porcelain margins with scanning electron micrographs. In the microscopic analysis of marginal closure, soldering without foil matrix was statistically equal to soldering with foil in place. Removal of the platinum foil matrices prior to indexing provided for no further seating of the metal ceramic retainers. Evaluation by scanning electron microscopy demonstrated distinct configuration changes in the porcelain margins for the specimens soldered without matrix support.

A procedure for restoring proximal contact surfaces of cast gold restorations with solder

Faulty contacts on restorations can be very damaging to the patient's dentition. Occasionally they are not corrected on a new restoration because of the length of time required for the procedure. The method described here is fast, simple, and protects the occlusal surfaces and margins of the restorations from damage while adding to the contacts with solder.

Tensile strength of preceramic solder joints formed using an infrared heat source

Infrared soldering was compared to gas-oxygen torch soldering by testing specimens made from each of the following four classes of metal ceramic alloys: gold-platinum-palladium, gold-palladium, palladium-silver, and nickel-chromium-beryllium. There was no significant difference between infrared and torch soldering for the gold-palladium, palladium-silver, and base metal alloy specimens. However, infrared soldering of the gold-platinum-palladium alloy samples produced significantly weaker joints than those produced by torch soldering.

Soldering technique for osseointegrated implant prostheses

This article describes a method for making changes in the alignment of superstructures for osseointegrated implants. After a cast is made from a transfer impression, the teeth and plastic are removed from the framework. The framework is sectioned into as many pieces as necessary to realign it on the analogs in the cast. The pieces are held in soldering investment with guide pins and abutment screws for soldering in the new position. The prosthesis is completed, finished, and replaced in the mouth.

Soldering procedure for repairing a full cast gold restoration

Repairing a small hole in a cast gold restoration can often be frustrating. The method described here using platinum fold to obliterate the hole to give the solder a medium to flow across is superior to most other methods of repairing crowns and is almost foolproof. This method requires the use of the die on which the crown wa made and the use of soldering investment.

Tensile strength analysis of midpontic soldering

A total of 120 three-unit fixed partial dentures were made by using a latex mold to produce uniform wax patterns. Four groups were used to compare the tensile strength of connectors with interproximal solder, midpontic vertical solder, midpontic diagonal solder, and a control of one-piece castings. Three different metals were tested and the tensile load required to fracture the samples as well as the fracture sites were recorded. The following was found: Soldering the interproximal connector area produced the weakest solder joints, regardless of metal tested, at p less than .001. There was no significant difference in the fracture loads between midpontic vertical soldering and midpontic diagonal soldering with all three metals at p less than .01. There was no significant difference in fracture loads between midpontic soldering and unit casting with all three metals at p less than .01. The extreme variations in fracture loads when soldering nickel-chrome-beryllium confirms the technique sensitivity of presoldering this alloy.