IADR Abstract Archives
Dental Microscope Filters Improving Visibility During Light-curing-composite Application
Objectives: Operating microscopes use bright light sources with a wide visible spectrum decreasing working time of light-curing restorative materials. Orange filters prevent unintended polymerization with less visibility of tooth structures and restorations.
Therefore, it was the aim of the study (i) to assess the prolongation of working time of light-curing composites by experimental filters and (ii) to improve operating visibility with white light (CRI>80) and (iii) to compare with traditional orange filters.
Methods: Three experimental filters (GF1-3), the standard orange filter (GFZeiss) and unfiltered xenon light (20klx) of Zeiss OPMI Pico microscope were used. Composite materials with different photoinitiators were tested (Charisma/shade A2, Venus Diamond/A2: Heraeus, Hanau, Germany; GrandioSo/A2: Voco, Cuxhaven, Germany; Tetric EvoCeram Bulk Fill/IVB: Ivoclar Vivadent, Liechtenstein).
Polymerisation over time was assessed every second with a vertical oscillating rheometer for each composite, each cycle was repeated 7 times. Prolongation factors for working time were defined at a viscosity level change of 50% and statistically analyzed using t-test and U-test. Photometrical analysis was provided for color temperature (K) and Color-Rendering-Index (CRI).
Results: The new light filters extended the working time significantly. Prolongation factors: no_filter=1; GF1=1.7-2.6; GF2=2.5-4; GF3=1.2-1.8. The working time varied depending on the composite formulation. The orange filter allowed unlimited working time.
Effect on light and color conditions: the color reproduction of the orange filter GFZeiss was poor due to the monochromatic light. Photometric analysis for CRI: Xenon>90; GF1=88.1; GF2=88.6; GF3=89; GFZeiss=n.a.. Color temperature for Xenon: 6000K; GF1=3834K; GF2=3778K; GF3=2556K; GFZeiss=2541K. GF1 and GF2 provided neutral white light color with a good color reproduction superior to the xenon light source.
Conclusions: All experimental filters prolonged the clinically acceptable working time and improved the CRI to the value of neutral white light (GF1 and GF2) and warm white (GF3) providing clinically optimal distinction of different tooth structures and composite colors.
Therefore, it was the aim of the study (i) to assess the prolongation of working time of light-curing composites by experimental filters and (ii) to improve operating visibility with white light (CRI>80) and (iii) to compare with traditional orange filters.
Methods: Three experimental filters (GF1-3), the standard orange filter (GFZeiss) and unfiltered xenon light (20klx) of Zeiss OPMI Pico microscope were used. Composite materials with different photoinitiators were tested (Charisma/shade A2, Venus Diamond/A2: Heraeus, Hanau, Germany; GrandioSo/A2: Voco, Cuxhaven, Germany; Tetric EvoCeram Bulk Fill/IVB: Ivoclar Vivadent, Liechtenstein).
Polymerisation over time was assessed every second with a vertical oscillating rheometer for each composite, each cycle was repeated 7 times. Prolongation factors for working time were defined at a viscosity level change of 50% and statistically analyzed using t-test and U-test. Photometrical analysis was provided for color temperature (K) and Color-Rendering-Index (CRI).
Results: The new light filters extended the working time significantly. Prolongation factors: no_filter=1; GF1=1.7-2.6; GF2=2.5-4; GF3=1.2-1.8. The working time varied depending on the composite formulation. The orange filter allowed unlimited working time.
Effect on light and color conditions: the color reproduction of the orange filter GFZeiss was poor due to the monochromatic light. Photometric analysis for CRI: Xenon>90; GF1=88.1; GF2=88.6; GF3=89; GFZeiss=n.a.. Color temperature for Xenon: 6000K; GF1=3834K; GF2=3778K; GF3=2556K; GFZeiss=2541K. GF1 and GF2 provided neutral white light color with a good color reproduction superior to the xenon light source.
Conclusions: All experimental filters prolonged the clinically acceptable working time and improved the CRI to the value of neutral white light (GF1 and GF2) and warm white (GF3) providing clinically optimal distinction of different tooth structures and composite colors.