EFFICIENCY OF WAX REMOVAL

MECHANICALLY MODIFIED SURFACES OF DENTURE BASE RESIN (PMMA) USING HOT WATER AT DIFFERENT TEMPERATURES WITH ADDED DETERGENT

Abstract

Objectives: To Determine the efficiency of wax removal from denture base
resin using hot water at a range of temperatures with added detergentand to Study the effects
of mechanically modified surfaces of denture base resin on the efficiency of dewaxing using
the above techniques. Settings: Eastman Dental Institute University Of London UK. Period:
Jan 2007 to June 2007. Material and Methods: In this study cast acrylic rods 13 mm long
and 6 mm in diameter were used. Three different surfaces were prepared for each rod,
described as Polished, Abraded & Grooved. Nine experimental groups, each consisting of ten
specimens were mechanically modified were contaminated with modeling wax, and then those
in each group were subjected to agitation in hot water with detergent at different range of
temperatures. The surfaces were then examined for traces of wax using Raman spectroscopy.
Results: The spectrum for each specimen demonstrated peaks at different wavelengths and
varying intensities, the spectra demonstrated traces of wax on abraded surfaces showed
least wax when dewaxed at 100°C as compared abraded surfaces dewaxed at 65°C and 85°
C temperatures respectively. Conclusion: The rough surfaces (abraded or grooved) showed
more wax retention as compared to polished surfaces. These surfaces are usually prepared by
the dental technician in a belief that modifying the ridge-lap area of the teeth will increase the
bond strength between the teeth and the denture base. Residual wax can still remain on the
tooth surface even after dewaxing it at 100˚C with detergent added to the water.