Casting accuracy greatly depends upon the setting expansion of the phosphate investment material. However, setting expansion is obstructed by the wax pattern. In this study, the flow of paraffin wax was and the relationship between flow and casting shrinkage was investigated.
The results were as follows:
1. Casting shrinkage decreased with an increasing flow of wax pattern.
2. Gypsum investment material had a lower setting gypsum expansion than two kinds of phosphate bonded investment materials, but its heat expansion was higher than that of the other two.
3. The setting expansion of the investment material was considerably influenced by the load, with the GC investment material being influenced the most.
4. The casting shrinkage of phosphate bonded investment material was more affected by the flow of wax than the gypsum bonded investment material.
