Marginal Accuracy of Castings Fabricated with Ringless Casting Investment System and Metal Ring Casting Investment System: A Comparative Study
BG Prasanna, M Kalavathi, Bhuvana Sachin, TV Shreeharsha, B Praveen, Mallikarjuna Ragher
Citation Information :
Prasanna B, Kalavathi M, Sachin B, Shreeharsha T, Praveen B, Ragher M. Marginal Accuracy of Castings Fabricated with Ringless Casting Investment System and Metal Ring Casting Investment System: A Comparative Study. J Contemp Dent Pract 2016; 17 (2):165-170.
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
The castings of the ringless technique provided less vertical marginal discrepancy (240.56 ± 45.81μ) than the castings produced with the conventional metal ring technique (281.98 ± 53.05μ). The difference was statistically significant.
Conclusion
The ringless casting technique had produced better marginal accuracy compared with conventional casting technique. Ringless casting system can be used routinely for clinical purpose.
How to cite this article
Kalavathi M, Sachin B, Prasanna BG, Shreeharsha TV, Praveen B, Ragher M. Marginal Accuracy of Castings Fabricated with Ringless Casting Investment System and Metal Ring Casting Investment System: A Comparative Study. J Contemp Dent Pract 2016;17(2):165-170.
Dimensional accuracy analysis of implant framework castings from 2 casting systems. Int J Oral Maxillofac Implants 2005 Sep-Oct;20(5):720-725.
Effect of a two-step ringless investment technique on alloy castability. J Prosthet Dent 1985 Jun;53(6):874-876.
Analysis of the marginal gap of complete crowns made by using wet and dry ceramic ring liner—an in vitro study. J Indian Prosthodont Soc 2005;5(3):152-154.
Three factors affecting investment setting expansion and casting size. J Prosthet Dent 1983 Jan;49(1):52-58.
The expansion of phosphate-bonded investment: part I—setting expansion. J Prosthet Dent 1993 Aug;70(2):121-125.
Nonuniform vertical and horizontal setting expansion of a phosphate bonded investment. J Prosthet Dent 1999 Apr;81(4):386-391.
The effect of time between mixing and heat on the expansion of phosphate-bonded investment. Aust Dent J 1986 Jun;31(3):207-213.
Non-restraining factors affecting setting expansion of phosphate-bonded investments. Scand J Dent Res 1986 Feb;94(1):77-81.
Effect of wax melting range and investment liquid concentration on the accuracy of a three-quarter crown castings. J Prosthet Dent 2002 Jan;87(1):57-61.
Influence of heating rate in thermal expansion of dental phosphate-bonded investment material. Scand J Dent Res 1990 Feb;98(1):60-65.
Strength of phosphate-bonded investments at high temperature. Dent Mater 1991 Apr;7(2):99-102.
Effect of ring liner and casting ring temperature on the dimension of cast posts. J Prosthet Dent 2000 Jul;84(1):32-37.
Marginal fit of nickel–chromium copings before and after internal adjustments with duplicated stone dies and disclosed agent. J Prosthet Dent 2000 Jun;83(6):634-643.
An investigation of the potential biohazards associated with asbestos-substitute casting ring liners. J Prosthet Dent 1987 Jan;57(1):108-112.
Effect of stone enhancer on marginal fit of nickel chromium cast copings. Anaplastology 2013;2(3):114.
Accuracy of ringless casting and accelerated wax-elimination technique: a comparative in vitro study. J Prosthodont 2014 Feb;23(2):157-162.
Dimensional accuracy of castings fabricated with ringless and metal ring investment systems for implant supported fixed dental prosthesis: an in vitro comparative study. MJAFl 2011 Jan;67(1):46-51.
