Resin composite pre-heating is a recent innovative method that could be clinically beneficial by improving handling and marginal adaptation of the unset material paste.
The aim of this study was to gather all the laboratory trials regarding resin composite pre-heating and investigate how this technique affects the material.
An electronic search was carried out in PubMed and Google scholar databases, covering the period from January 2003 to May 2018. Specific criteria were set in order to define the relevance of each study.
Eighteen articles were included. The most commonly studied variable was the degree of conversion. Five studies found it increased and two not statistically significant different. Marginal adaptation, viscosity and polymerization shrinkage were higher. Flexural strength found to be unaffected. The results varied about microhardness and polymerization shrinkage.
Preheating has positive effect on the degree of conversion, viscosity, marginal adaptation and microhardness of composite resins. The flexural strength remains unaffected, the polymerization shrinkage is worsened, while the results for the microleakage are unclear. Further studies are need to take place in order to assess the clinical significance of composite pre-heating.