Temperature rises produced by light sources and composites during curing

Comparison of the Amount of Temperature Rise in the Pulp Chamber of Teeth Treated With QTH, Second and Third Generation LED Light Curing Units: An In Vitro Study

“…The similar results were obtained in the study by Kavitha et al 19 Here, the LED units produced little temperature increase when compared to QTH units. This result was also in accordance with the findings of McCabe 20 and Lloyd et al 12 While evaluating the in vivo simulation, the sum of all the exposures seems to cause a considerable rise in pulpal temperature. The maximum temperature rise observed was 4.0°C for QTH unit, which was well below the limits that affect the integrity of the dental pulp.…”

“…It has been stated that the main influencing factor for temperature rise, during the light-activated polymerization of composites, is the energy emitted from the LCU; and the exothermic composite polymerization process is only of secondary importance to the temperature rise. 2,12 The first part of our study was designed according to the study done by Yap and Soh. 13 it is apparent that as the distance between light curing unit and the tooth decreases, the temperature tends to rise.…”

Effect of the Curing Temperature of Dental Composites evaluated with a Fluorescent Dye

“…At the outset, in our view, understanding how the curing temperature influences the polymerization process would allow a better understanding of this modification imposed by the use of a photopolymerization source that raises the temperature less during its operation. 8 Like any chemical reaction, the polymerization is also affected depending on the thermal agitation present in the molecules that constitute them. Therefore, temperature variations during the curing process may modify the properties of the final cured resin and its molecular arrangement.…”

“…However, as in research conducted by Wu,5 De Gee et al, 6 and Andrade, 7 this penetration of molecules can be used as a method to evaluate the polymerization of these composite resins, because the diffusion rate of penetrants depends on the free volume of the polymer formed, and this free volume depends on the form of polymerization and degree of conversion. [6][7][8][9] Considering the probable influence of the thermal energy supply on the photopolymerization process, we will investigate, through a different methodology from the traditional evaluation methods, such as degree of conversion [Fourier transform infrared (FTIR)] and microhardness, the consequences of the temperature variation during curing through the quantification of the penetration of an organic and fluorescent dye into the mass of the composite resin photopolymerized by two LEDs and a halogen lamp.…”

“…As the reaction of monomers into polymers is an exothermic process, a further increase of heat will occur proportional to the rate of reaction and the degree of polymerization. This increase will also be elevated even more due to the irradiance of the light used, 8 which becomes another modifying factor of the kinetics of cure. We can then verify the occurrence of two distinct situations in which the temperature change can influence the photopolymerization process.…”