What effect does rising temperature above 100ºC have on heat-cured denture-base acrylic resins?

When heat-cured denture-base acrylic resins are subjected to rising temperatures above 100ºC, it leads to chemical and physical changes in the material. Specifically, the increase in temperature can cause the resin to become increasingly less viscous, promoting the release of volatile components and the formation of bubbles during the curing process.

As a result, porosity tends to develop primarily within the internal portion of the resin. This internal porosity is a consequence of trapped gas or vapor that can expand and create voids as the resin cures. While surface characteristics can also be affected, the most significant impact on porosity is observed internally, influencing the mechanical properties and the overall integrity of the dentures made from these materials.

Understanding this effect is critical in the field of dentistry, as it can significantly impact the performance, durability, and comfort of denture appliances. Proper temperature control during the curing process is essential to mitigate the risk of internal porosity and ensure a high-quality final product.