Abstract
Aim: To investigate the performance of multiple Light-curing Units (LCUs) of different manufacturers used in a dental student clinical setting. Background: Manufacturers claim that the irradiance values of the LCUs stay stable over time. However, this may not be accurate among the different units. Objective: This study investigated the performance in terms of the irradiance, radiant exposure, and DOC of multiple LCUs of different types used in a dental student clinical setting. Methods: Four different LCU were investigated (n=5 units/LCU manufacturer): three Light-Emitting-Diodes (LED) units (Demi Ultra, Mini LED, and E-Morlit) and one quartz-tungsten-halogen (QTH) (PolyluxII). Irradiance and radiant exposure were collected [Managing Accurate Resin Curing-Patient Simulator (MARC-PS)](n=5 readings/unit/tooth). Depth of Cure (DOC) was performed (ISO 4049:2009standards) using a micro-hybrid composite (n=5/unit). Data were analyzed using Kruskal-Wallis and ANOVA followed by Student-Newman-Keuls and Tukey post hoc methods, respectively (α=0.05). Results: Using the MARC-PS anterior and posterior teeth sensors, respectively, the mean irradiance for Demi Ultra was (1625.7±38.8) and (1250.4±25.2); Mini LED (1381.1±37.8) and (1058.1±27.3); E-Morlit (1831.1±294.7) and (1545.2±176.0); and Polylux II (932.4±368.5) and (840.4±353.4)mW/cm2. The radiant exposure range was 16-38 J/cm2 for all LCUs. LCUs’ mean DOC ranged from 2.9 to 3.1 mm. Significant differences in irradiance and radiant exposure values were detected among the multiple units and manufacturers. Significant differences in DOC values among the Demi Ultra and Polylux II units were detected. DOC met the standards except for onePolylux II unit. Conclusion: The irradiance and radiant exposure values were not the same among the different units, regardless of the manufacturers’ claim of the irradiance values stability over time. Polymerization was not compromised except for one QTH unit per the DOC measurements. Itis highly recommended to closely monitor LCUs used in dental student clinical areas due to the high demand in this type of setting.
Highlights
The performance of Dental Light-curing Units (LCUs) influences both the polymerization effectiveness and clinical longevity of Resin-based Composite (RBC) restorations [1], since the latter need receiving sufficient energy at a specific wavelength to acquire satisfactory chemical, physical and mechanical properties [2 - 6]
This study investigated the performance in terms of the irradiance, radiant exposure, and Depth of Cure (DOC) of multiple LCUs of different types used in a dental student clinical setting
Significant differences in irradiance and radiant exposure values were detected among the multiple units and manufacturers
Summary
The performance of Dental Light-curing Units (LCUs) influences both the polymerization effectiveness and clinical longevity of Resin-based Composite (RBC) restorations [1], since the latter need receiving sufficient energy at a specific wavelength to acquire satisfactory chemical, physical and mechanical properties [2 - 6]. During the polymerization of RBC restorations, the professional must always verify the quality of the LCU under usage This is usually overlooked by dental students. Manufacturers claim that the light-emitting-diode (LED) curing units’ performance and irradiance remain stable until the battery runs out, and the stability is maintained over time. This may not be the case, and irradiance levels may be impacted by the high level of usage by dental students [8]. This may not be accurate among the different units
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