Temperature changes and thermo-light polymerization efficacy of two LED curing lights and 445-nm diode laser on glass carbomer material

Abstract

Purpose: To evaluate thermo-light polymerization efficacy on the Vickers microhardness (VH) of a glass carbomer material (GCP) and on temperature changes (ΔT) using a diode laser (445 nm, DL) and two light-emitting diode (LED) units. Methods: Fifty-four GCP samples (2 × 8 mm) were prepared and exposed to three polymerization units: GCP CarboLED (G1), 3 M Elipar™ DeepCure-S (G2), and 445-nm SIRO Laser Blue (G3). A K-type thermo-couple was used to measure ΔT. After 24 h, VH values were measured, and surface changes were evaluated. The data were analysed by t test, one-way analysis of variance (ANOVA) and Welch ANOVA, and Tamhane post hoc tests (p < 0.05). Results: Both ΔT and VH measurements were evaluated; G1 showed significantly lower temperature increase values and lower VH values than the other groups (p < 0.001), but no significant difference was observed between G2 and G3(p > 0.05). There were no alterations in surface morphology or chemical composition of GCP after laser treatment. Conclusion: 3 M Elipar and 445-nm DL applications yielded higher VH compared to GCP CarboLED, but with higher temperature increases. Application of 445 nm DL has the advantage of causing no difference between top and bottom VH values. Clinical significance. Our data reveal that heat application with any one of these three devices was safe for all treatment groups without causing pulp damage. © 2021, The Author(s), under exclusive licence to Springer Nature Switzerland AG.