Crown pattern waxes: a study of their behavior on heating and cooling

Area of Science:

• Materials Science
• Dental Materials Science

Background:

• Dental waxes are crucial for crown fabrication.
• Understanding their physical properties is essential for clinical success.
• Previous studies have indicated limitations in current dental wax formulations.

Purpose of the Study:

• To determine critical physical properties, specifically flow and linear thermal expansion, of crown pattern waxes.
• To compare these properties with previously reported data.
• To investigate the correlation between cooling curve arrest points and transition points in flow and expansion.

Main Methods:

• Measurements were conducted using the American Dental Association's proposed method.
• Testing occurred within a temperature range of 27 to 52 degrees C.
• Cooling curves were analyzed to identify arrest points indicative of material composition.

Main Results:

• Most tested waxes showed low, suitable flow values above 37 degrees C.
• Significant linear thermal expansion was observed, ranging from 1% to 1.5% or more between 27 and 47 degrees C.
• Arrest points on cooling curves were recorded and analyzed for correlation with flow and expansion transitions.

Conclusions:

• While dental waxes exhibit suitable flow for laboratory use, their thermal expansion remains a significant drawback.
• Current dental waxes, despite improvements, are not entirely free from issues related to large and potentially uncontrollable thermal expansion.
• Further research may be needed to develop dental waxes with more stable thermal properties.