Self- and light-curing: characteristics and differences of resins for relining temporary prostheses

In recent years, the temporary prosthesis, i.e. the temporary or transitional prosthesis that accompanies the patient from the beginning of the prosthetic therapy until the birth of the definitive prosthesis, has undergone changes in its potential use. This clinical step, a transitory time to guarantee the patient the chewing comfort, has become a useful and precious moment to optimize the final prosthesis both from a functional point of view – reviewing the bite – and from a purely aesthetic point of view.

In general, temporary prostheses should be considered as a valid test to determine what the final prostheses will be. For this reason, it is vital for the dental practice to have all the tools and technical products necessary for the rapid overturning of the temporary prosthesis at hand (in other words, restoring its base, to ensure greater stability and adhesion), even without a frame, directly from the chair.

For this treatment, self-curing acrylic resins are used and, more recently, some light-curing resins are also used. The latter, unlike the former, avoid possible complications and problems such as overheating and excessive adhesion to the abutment; critical problems that require the application of glycerine or other insulating materials. This characteristic of light-curing resins is due to their fluid or viscoelastic properties prior to polymerization, low thermal irritation, and reduced release and thus the accumulation of free monomers. 

The differences between the two types of resin for temporary dental prosthesis also concern their chemical composition: compared to self-curing resins, light-curing resins also contain a photoinitiator, i.e. a molecule capable of transferring light energy to trigger polymerization. On the contrary, a component present in self-curing resins and missing in light-curing resins is a chemically activated accelerator (e.g. N, N-Dimethyl-o-toluidine). Products certified as self-curing and light-curing contain both components: the chemical accelerator and the photoinitiator.