The Influence of The Coefficient of Thermal Expansion of Dental PMMA

The coefficient of thermal expansion of dental PMMA has a significant impact on its application, mainly reflected in the following aspects:

Compatibility with natural teeth and artificial porcelain teeth

The coefficient of thermal expansion of thermosetting PMMA bases is much larger than that of natural teeth and artificial porcelain teeth. In an environment with cold and hot changes, due to the different degrees of expansion, it is easy for the porcelain teeth connected to the resin base or the resin around the porcelain teeth to crack, or for the connection between the base and the porcelain teeth and related metal materials to become loose, thereby affecting the normal use of the denture base. For instance, when the temperature of the oral environment changes, the expansion or contraction degree of the PMMA base is inconsistent with that of natural teeth and porcelain teeth, which may cause stress concentration at the connection point and subsequently lead to cracking or loosening.

Dimensional stability of dentures

The PMMA base will undergo thermal expansion or contraction when the temperature changes, which will affect the dimensional stability of the denture. If the size of a denture changes due to temperature variations in the oral cavity, it may lead to a poor fit between the denture and the oral tissues, causing discomfort to the patient and even affecting the chewing and pronunciation functions of the denture. For instance, when patients consume cold or hot food, dentures may undergo slight dimensional changes due to the existence of the coefficient of thermal expansion. Over time, this could affect the performance of the dentures.

Clinical operation precautions

Due to the thermal expansion coefficient characteristic of PMMA, some matters need to be noted in the process of denture manufacturing and clinical use. For instance, during the manufacturing process of dentures, the influence of the coefficient of thermal expansion on the size of the dentures should be taken into account. The processing technology and temperature conditions should be reasonably controlled to ensure the dimensional accuracy of the dentures. In clinical use, it is necessary to remind patients to avoid soaking and cleaning dentures in overly hot liquids to prevent deformation of the dentures due to thermal expansion.