Marginal Accuracy of Castings Fabricated with Ringless Casting Investment System and Metal Ring Casting Investment System: A Comparative Study

Abstract

Background:The thermal expansion of the investment can be restricted by the metal casting ring because the thermal expansion of the ring is less than that of the investment. The ringless casting procedure is in use in clinical dentistry, though there is little scientific data to support its use in fixed partial dentures. In this study, marginal discrepancy of castings produced with the ringless casting technique and the conventional technique using the metal rings were compared. Materials and methods:A total of 30 wax patterns were fabricated directly on a metal die. Optical stereomicroscope was used to measure the marginal discrepancy between the metal die and wax patterns. A total of 15 castings were invested using Bellavest T phosphate-bonded investment with the ringless technique and 15 were invested with the same investment with a metal ring; 30 castings were produced using a nickel-chromium ceramo-metal alloy. The internal surface of the castings was not modified and seated with finger pressure. The vertical marginal discrepancy was measured using an optical stereomicroscope at a magnification of 100×. The data obtained were statistically analyzed using students t-test (paired t-test and unpaired t-test). Results

Comparative evaluation of marginal accuracy of metal copings fabricated using direct metal laser sintering, computer-aided milling, ringless casting, and traditional casting techniques: An In vitro study

“…However, the findings of this study are comparable to some of the previous studies. [ 2 9 14 15 16 ]…”

The effect of casting ring liner length and prewetting on the marginal adaptation and dimensional accuracy of full crown castings

“…[12] Casting ring liner length and width are among the multiple factors that influence the setting and thermal expansion of the mold. [13] The ring liner provides a controlled space for unhindered expansion of mold within the metal casting ring.…”