Effect of radiant heat on conventional glass ionomer cements during setting by using a blue light diode laser system (445 nm)

Abstract

The aim of this in vitro study was to evaluate the effect of radiant heat on surface hardness of three conventional glass ionomer cements (GICs) by using a blue diode laser system (445 nm) and a light-emitting diode (LED) unit. Additionally, the safety of the laser treatment was evaluated. Thirty disk-shaped specimens were prepared of each tested GIC (Equia Fil, Ketac Universal Aplicap and Riva Self Cure). The experimental groups (n = 10) of the study were as follows: group 1 was the control group of the study; in group 2, the specimens were irradiated for 60 s at the top surface using a LED light-curing unit; and in group 3, the specimens were irradiated for 60 s at the top surface using a blue light diode laser system (445 nm). Statistical analysis was performed using one-way ANOVA and Tukey post-hoc tests at a level of significance of a = 0.05. Radiant heat treatments, with both laser and LED devices, increased surface hardness (p < 0.05) but in different extent. Blue diode laser treatment was seemed to be more effective compared to LED treatment. There were no alterations in surface morphology or chemical composition after laser treatment. The tested radiant heat treatment with a blue diode laser may be advantageous for the longevity of GIC restorations. The safety of the use of blue diode laser for this application was confirmed.

Evaluation of Surface Microhardness and Abrasion Resistance of Two Dental Glass Ionomer Cement Materials after Radiant Heat Treatment

“…This is in agreement with previous studies which investigated the effect of radiant heat treatments on surface hardness of GIC materials [8,9,11,12,15]. Thermal energy providing by the LED light-curing unit increased surface hardness of the tested GIC materials by thermocatalysis.…”

“…In previous studies various techniques have been suggested in order to increase the surface hardness of the GIC 2 Advances in Materials Science and Engineering materials, which include radiant heat transfer by use of dental light-curing units such as light emitting diodes (LEDs) [9][10][11] or lasers [12], ultrasonic energy transfer to enhance the motivation and interaction of the reacted components of the GIC [9,13,14], and application of calcium chloride (CaCl 2 ) solutions in order to enhance the acid-base reaction between carboxylate groups (-COO − ) of the polyalkenoic acids and calcium cations (Ca +2 ) of the glass particles of the cement [15,16]. Among the above techniques the most common one for improving the physical and mechanical properties of the GIC materials is the radiant heat treatment using dental LED curing units.…”

Is it Possible to Improve the Clinical Behaviour of Glass Ionomer Cement Restorations?

“…There are previous studies that demonstrated increase in surface hardness [15,16], compressive strength [6] and abrasion resistance [19], as well as decrease in solubility and water sorption [20] of various GIC restoratives after radiant heat treatments with LED or laser (diode -445 nm) units. Furthermore, the safety of these treatments on the surface of the restorations (surface morphology and roughness) [13,20] and as regards with the pulp temperature rise [12,13], has been confirmed. On the other hand, it has been reported decrease in fluoride release after the radiant heat treatment due to the improvement of the setting reaction of the GICs and their decrease in solubility [11,16].…”

“…The final material consists of unreacted glass particles and a poly-salt matrix with cross-link bonds [10]. In previous studies various techniques have been suggested in order to improve the physical and mechanical properties of the conventional GICs, which include radiant heat transfer by use of dental light-curing units such as light emitting diodes (LEDs) [6,11,12] or lasers [13], ultrasonic energy transfer to enhance the motivation and interaction of the reacted components of the GIC [11,14,15] and application of calcium chloride (CaCl 2 ) solutions in order to enhance the acidbase reaction between corboxylate groups (-CΟΟ -) of the polyalkenoic acids and calcium cations (Ca +2 ) of the glass particles of the cement [16,17].…”

“…It is worth noting that induced heat and not output power of a light source is crucial for the thermo-catalysis of the reactions. As a matter of fact, the parameter which is related to the effectiveness of this method is the amount of heat transfer on the surface of the material which depends on thermal emission and duration of the irradiation of the light source [12,13].…”