Casting Ring Liners and the Ringless Casting Technique on Marginal Adaptation of Casting Crown WITHDRAWN

Aim: In this study, the effects of the four common investing methods
(one-layer dry casting ring liner, one and two-layer wet casting ring liner
and ring less casting technique) on the marginal gap of castings on the die were
examined.
Material and Methods: Ten wax patterns were invested utilizing each of the
four above-mentioned methods by phosphate-bonded investment and then the
marginal gap of each casting on a die, under a stereoscopic microscope, was
measured in micron by a blind operator. Plus, the one-way univariate
analysis of variance (ANOVA) and the Post Hoc test (Tukey HSD multiple
comparisons) were run at p=0.05.
Results: The mean ± SD for the castings marginal gap in the four investing
techniques was: (86 ± 33 μm) in the method of one-layer dry casting ring
liner
Conclusions: The one and two-layer wet casting ring liner methods are the
reliable and appropriate techniques for producing the dental castings
according to the clinically acceptable marginal gaps, (46 ± 32 μm) in the method of
one-layer wet casting ring liner, (50 ± 28 μm)
in the method of two-layer wet casting ring liner and (163 ± 77 μm) in the
method of ring less casting. The differences were statistically significant
(p<0.05).
Key words: Dry casting ring liner, Wet casting ring liner, Ring less
casting technique, Marginal adaptation