Date of Award
Spring 1994
Document Type
Thesis - Restricted
Degree Name
Master of Science (MS)
Department
Dentistry
First Advisor
Dhuru, Virendra
Second Advisor
Ziebert, Gerald
Third Advisor
Walker, Jerry
Abstract
Physical and mechanical properties of two commonly used denture base materials and a recently introduced denture base material were compared in this investigation. The materials were pressure molded Lucitone 199 (Dentsply International Inc., York, PA); injection molded SR-Ivocap (Ivoclar, North America, Inc., St. Charles, IL); and the new material pressure molded ProBase Hot (Ivoclar, North America, Inc., St. Charles, IL). Physical properties of polymerization shrinkage, water sorption and water desorption, and the mechanical properties of deflection in three point bending (ADA Specification No. 12), modulus of rupture and modulus of elasticity were evaluated. Polymerization shrinkage was measured by comparing the linear measurement of the wax pattern and the processed acrylic plate. Water sorption and desorption were evaluated by monitoring the weights of rectangular specimens measuring 50mm x 10mm x 2.5mm in dry condition, after storing under water for four weeks and after allowing to dry in air for additional four weeks. The weights were obtained on a weekly basis to the accuracy of 0.1 mg. These specimens were subjected to three point bending in an Instron Universal testing machine at a cross-head speed of 5.1mm per minute and the resulting deflection was recorded on the chart. The deflection was measured from the chart to the nearest 5 microns. The values of deflection for the three materials under dry, sorped and desorped conditions, for the load level of 8000 g, were compared. The values for the modulus of rupture and modulus of elasticity were calculated from the data related to deflection and the dimensional measurements of the specimens utilizing the standard engineering equations. Approximately seven specimens were included for each combination of the material and the variables such as dry, sorped and desorped. The results indicated that there was no statistically significant difference between the polymerization shrinkage of the three materials. Most of this shrinkage appeared to have been compensated for by the increase in linear dimension exhibited by all three materials after sorption in water for four weeks. There was a significant difference between the sorption and desorption weights of the three materials. ProBase Hot showed significantly less deflection and greater transverse strength than the other two materials. Deflection was significantly greater for specimens of all three materials under sorped condition than in the dry and desorped conditions. All the specimens of ProBase Hot fractured within a range between 9000 g load to 10000 g load but not all the specimens reached this value of load before fracturing. Only 5% of the Lucitone specimens and 25% of the SR-Ivocap specimens showed fracture. ProBase Hot may exhibit a greater incidence of fracture in clinical situations.
Recommended Citation
Shibat Alhamed, Yousef Abdulgader, "A Comparison of Polymerization Shrinkage, Water Sorption and Transverse Strength of Three Denture Base Materials" (1994). Master's Theses (1922-2009) Access restricted to Marquette Campus. 5339.
https://epublications.marquette.edu/theses/5339