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Frederick A Rueggeberg - One of the best experts on this subject based on the ideXlab platform.
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Accuracy of Irradiance and Power of Light-Curing Units Measured With Handheld or Laboratory Grade Radiometers.
Brazilian Dental Journal, 2019Co-Authors: Marcelo Giannini, Carolina Bosso André, Vanessa Cavalli Gobbo, Frederick A RueggebergAbstract:This study measured and compared exitance irradiance and power of 4 commercial Dental Light-Curing units (LCU) (Elipar S10, Elipar DeepCure-S, Corded VALO and Bluephase Style) using different types of radiometers. The devices used to analyze the LCU were classified as either handheld analog (Henry Schein, Spring, Demetron 100A, Demetron 100B and Demetron 200), handheld digital (Bluephase 1, Bluephase II, Coltolux, CureRite and Hilux), or laboratory instruments (Thermopile and Integrating Sphere). The laboratory instruments and the Bluephase II radiometer were also used to measure the LCU's power (mW). The LCU's were activated for 20 s (n=5). Data were analyzed using Kruskal-Wallis and Student-Newman-Keuls multiple comparison test (a=0.05). Among the LCU, the laboratory instruments presented different irradiance values, except for Corded VALO. The Coltolux and Hilux radiometers measured greater irradiance values compared to the laboratory instruments for the four LCUs tested. Within a given LCU, handheld analog units measured lower irradiance values, compared to handheld digital and laboratory instruments, except using the Spring radiometer for the Elipar S10 LCU. None of the handheld radiometers were able to measure similar irradiance values compared to laboratory instruments, except for Elipar S10 when comparing Bluephase 1 and Thermopile. Regarding power measurement, Bluephase II always presented the lowest values compared to the laboratory instruments. These findings suggest that the handheld radiometers utilized by practitioners (analog or digital) exhibit a wide range of irradiance values and may show lower outcomes compared to laboratory based instruments.
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Effect of indirect restorative material and thickness on light transmission at different wavelengths
Journal of prosthodontic research, 2018Co-Authors: Rafael Rocha Pacheco, Frederick A Rueggeberg, Carolina Bosso André, Adriana Oliveira Carvalho, Ana Paula Almeida Ayres, Tiago M. Dias, Marcelo GianniniAbstract:Abstract Purpose The aim of this study was to evaluate the influence of indirect restorative material type and thickness on the transmission of different wavelengths from a broad-banded Dental curing light. Methods Four Dental indirect restorative materials for computer-aided design and computer-aided manufacturing (CAD/CAM) were evaluated: [RC] resin/ceramic hybrid material (Lava Ultimate), [FC] feldspathic ceramic (VitaBlocs), and two zirconia-based ceramics ([ZK] Katana; and [ZL] Lava). Total loss of irradiance (TL) was measured for blue (WB, 425–490 nm) and violet (WV, 350–425 nm) wavelengths. Specimens of 15 × 15 mm with varying thicknesses (0.5, 1.0, 1.5, and 2.0 mm) were fabricated (n = 5). A plasma-arc Dental Light-Curing unit was used (Arc Light-II). To assess TL as a function of wavelength, a software (Spectra Suite v5.1) connected to a spectroradiometer (USB2000) and an integrating sphere (CTSM-LSM-60-SF) was used. Data was subjected to statistical analysis (two-way ANOVA and post-hoc Tukey test, α = 0.05). Results A 0.5 mm interposition resulted in TL from 50.5 to 67.2%, depending on material. Increased thickness resulted in higher TL for all materials. FC showed less TL compared to ZK. In general, WV showed higher TL than did WB, and WV/WB proportion decreased with increasing thickness. Conclusions Indirect materials significantly reduced TL, and this effect is greater with increasing thickness. WV showed lower penetration compared to WB.
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correlation between the beam profile from a curing light and the microhardness of four resins
Dental Materials, 2014Co-Authors: R B Price, Ivan Kostylev, Frederick A Rueggeberg, Daniel Labrie, Braden Sullivan, John FaheyAbstract:Abstract Objective To demonstrate the effect of localized irradiance and spectral distribution inhomogeneities of one LED-based Dental Light-Curing unit (LCU) on the corresponding microhardness values at the top, and bottom surfaces of four Dental resin-based composites (RBCs), which contained either camphorquinone (CQ) alone or a combination of CQ and monoacylphosphine oxide (TPO) as photoinitiators. Methods Localized irradiance beam profiles from a polywave LED-based LCU were recorded five times using a laser beam analyzer, without and with either a 400 nm or 460 nm narrow bandpass filter placed in front of the camera lens. Five specimens of each of the four RBCs (two containing CQ/TPO and two containing CQ-only) were exposed for 5-, 10-, or 30-s with the light guide directly on the top surface of the RBC. After 24 h, Knoop microhardness values were measured at 45 locations across the top and bottom surfaces of each specimen. Microhardness readings for each RBC surface and exposure time were correlated with localized patterns of the LCU beam profile, measured using the 400 nm and 460 nm bandpass filters. Spearman rank correlation was used to avoid relying on an assumption of a bivariate normal distribution for the KHN and irradiance. Results The local irradiance and spectral emission values were not uniformly distributed across the light tip. There was a strong significant positive correlation with the irradiance beam profile values from the LCU taken through bandpass filters and the microhardness maps of the RBC surfaces exposed for 5 and 10 s. The strength of this correlation decreased with increasing exposure time for the RBCs containing CQ only, and increased for the RBCs containing both CQ and TPO. Conclusions Localized beam and spectral distributions across the tip end of the light guide strongly correlated with corresponding areas of microhardness in both the top and bottom surfaces among four RBCs with different photoinitiator contents. Significance A Light-Curing unit with a highly inhomogeneous light output can adversely affect localized microhardness of resin-based composites and this may be a contributing factor for premature failure of a restoration.
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Localised irradiance distribution found in Dental light curing units
Journal of Dentistry, 2013Co-Authors: Pierre Luc Michaud, Frederick A Rueggeberg, Daniel Labrie, Richard B. Price, Braden SullivanAbstract:Abstract Objective To measure the localised irradiance and wavelength distributions from Dental light curing units (LCUs) and establish a method to characterise their output. Methods Using a laboratory grade integrating sphere spectrometer system (Labsphere and Ocean Optics) the power, irradiance, and spectral emission were measured at the light tips of four LCUs: one plasma-arc (PAC) unit, one single peak blue light-emitting diode (blue-LED) unit, and two polywave LED (poly-LED) units. A beam profiler camera (Ophir Spiricon) was used to record the localised irradiance across the face of the light tips. The irradiance-calibrated beam profile images were then divided into 45 squares, each 1 mm2. Each square contained the irradiance information received from approximately 3200 pixels. The mean irradiance value within each square was calculated, and the distribution of irradiance values among these 45 squares across the tip-ends was examined. Additionally, the spectral emission was recorded at various regions across each light tip using the integrating sphere with a 4 - mm diameter entrance aperture. Results The localised irradiance distribution was inhomogeneous in all four lights. The irradiance distribution was most uniformly distributed across the PAC tip. Both the irradiance and spectral emission from the poly-LED units were very unevenly distributed. Conclusions Reporting a single irradiance value or a single spectral range to describe the output from a curing light is both imprecise and inappropriate. Instead, an image of both the irradiance distribution and the distribution of the spectral emission across the light tip should be provided. Clinical significance The localised beam irradiance profile at the tip of Dental LCUs is not uniform. Poly-LED units may deliver spectrally inhomogeneous irradiance profiles. Depending on the photoinitiator used in the RBC and the orientation of the LCU over the tooth, this non-uniformity may cause inadequate and inhomogeneous resin polymerisation, leading to poor physical properties, and premature failure of the restoration.
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Irradiance differences in the violet (405 nm) and blue (460 nm) spectral ranges among Dental Light-Curing units.
Journal of esthetic and restorative dentistry : official publication of the American Academy of Esthetic Dentistry ... [et al.], 2010Co-Authors: Richard B. Price, Frederick A Rueggeberg, Daniel Labrie, Christopher M. FelixAbstract:Problem: Previous studies identified nonuniformity in the irradiance at the tip end of a variety of Dental Light-Curing units (LCUs) and correlated those differences with potential clinical implications, but the spectral dependence of the irradiance uniformity has not yet been addressed. Purpose: This study examined the irradiance uniformity across emitting tips of LCUs at two emission wavelengths, 405 and 460 nm. Two broadband emission light units (quartz-tungsten-halogen [QTH] and plasma arc [PAC]), and four commercial light-emitting diode (LED)-type LCUs were examined. Materials and Methods: The spectral radiant power from six LCUs was measured using a laboratory grade spectroradiometer (Ocean Optics, Dunedin, FL, USA). The spatial and spectral characteristics of irradiance across the emitting tips of these light units were recorded through 10-nm wide bandpass filters (centered at 405 nm [violet] or 460 nm [blue]) using a laser beam analyzer (Ophir-Spiricon, Logan, UT, USA). Irradiance distributions were reported using two-dimensional contour and three-dimensional isometric color-coded images. Irradiance uniformity at the tip end was determined using the Top Hat Factor (THF) for each filtered wavelength. Results: Irradiance distributions from the QTH and PAC units were uniformly distributed across the tip end of the light guide, and THF values, measured through the 405 and 460-nm filters, were not significantly different. However, the three polywave LED units delivered non-uniform irradiance distributions with THF values differing significantly between the 405 and 460-nm emission wavelengths for each unit. Areas of nonuniformity were attributed to the locations of the various types of LED chips within the LCUs. Conclusion: All three polywave LED units delivered a nonuniform irradiance distribution across their emitting tip ends at the two important emission wavelengths of 405 nm and 460 nm, whereas the broadband light sources (QTH and PAC) showed no evidence of spectral inhomogeneity at these wavelengths. CLINICAL SIGNIFICANCE Since the rate and extent of polymerization of photo activated restorative materials is highly dependent on delivering radiant energy at specific wavelengths, the nonuniform spectral distribution across the emitting tips of polywave light-emitting diode curing lights may affect the resulting properties of some photocured resins and their potential for long-term clinical success. (J Esthet Restor Dent 22:363–378, 2010)
Richard B. Price - One of the best experts on this subject based on the ideXlab platform.
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Three-dimensional beam profiling used to characterize Dental Light-Curing units.
Applied optics, 2019Co-Authors: S. M. Juckes, Ivan Kostylev, Richard B. Price, Braden Sullivan, Daniel LabrieAbstract:Two-dimensional (2D) beam profiling is an emerging technique used to characterize the beam homogeneity in Dental Light-Curing units (LCUs). This project developed a method to combine multiple 2D beam profiles that had been measured along the beam path to create a 3D profile of the beam. This allowed a quantitative investigation of beam divergence and homogeneity at different distances from the source. To illustrate the use of this technique, four representative Dental LCUs were measured. In addition, the selected Dental LCUs demonstrated the effects of LCU design, particularly that of fiber optic light guides, on beam quality. The results show the value of a program that can recombine multiple beam profile images made at different distances from the source to create a 3D beam profile of a light beam.
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Shedding light on a potential hazard: Dental Light-Curing units.
Journal of the American Dental Association (1939), 2019Co-Authors: Marie T. Fluent, Jack L. Ferracane, James G. Mace, Anjali R. Shah, Richard B. PriceAbstract:Abstract Background Dental Light-Curing units (LCUs) are powerful sources of blue light that can cause soft-tissue burns and ocular damage. Although most ophthalmic research on the hazards of blue light pertains to low levels from personal electronic devices, computer monitors, and light-emitting diode light sources, the amount of blue light emitted from Dental LCUs is much greater and may pose a “blue light hazard.” Methods The authors explain the potential risks of using Dental LCUs, identify the agencies that provide guidelines designed to protect all workers from excessive exposure to blue light, discuss the selection of appropriate eye protection, and provide clinical tips to ensure eye safety when using LCUs. Results While current literature and regulatory standards regarding the safety of blue light is primarily based on animal studies, sufficient evidence exists to suggest that appropriate precautions should be taken when using Dental curing lights. The authors found it difficult to find on the U.S. Food and Drug Administration database which curing lights had been cleared for use in the United States or Europe and could find no database that listed which brands of eyewear designed to protect against the blue light has been cleared for use. The authors conclude that more research is needed on the cumulative exposure to blue light in humans. Manufacturers of curing lights, government and regulatory agencies, employers, and Dental personnel should collaborate to determine ocular risks from blue light exist in the Dental setting, and recommend appropriate eye protection. Guidance on selection and proper use of eye protection should be readily accessible. Conclusions and Practical Implications The Centers for Disease Control and Prevention Guidelines for Infection Control in the Dental Health-Care Setting–2003 and the Occupational Safety and Health Administration Bloodborne Pathogen Standard do not include safety recommendations or regulations that are directly related to blue light exposure. However, there are additional Occupational Safety and Health Administration regulations that require employers to protect their employees from potentially injurious light radiation. Unfortunately, it is not readily evident that these regulations apply to the excessive exposure to blue light. Consequently employers and Dental personnel may be unaware that these Occupational Safety and Health Administration regulations exist.
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Localised irradiance distribution found in Dental light curing units
Journal of Dentistry, 2013Co-Authors: Pierre Luc Michaud, Frederick A Rueggeberg, Daniel Labrie, Richard B. Price, Braden SullivanAbstract:Abstract Objective To measure the localised irradiance and wavelength distributions from Dental light curing units (LCUs) and establish a method to characterise their output. Methods Using a laboratory grade integrating sphere spectrometer system (Labsphere and Ocean Optics) the power, irradiance, and spectral emission were measured at the light tips of four LCUs: one plasma-arc (PAC) unit, one single peak blue light-emitting diode (blue-LED) unit, and two polywave LED (poly-LED) units. A beam profiler camera (Ophir Spiricon) was used to record the localised irradiance across the face of the light tips. The irradiance-calibrated beam profile images were then divided into 45 squares, each 1 mm2. Each square contained the irradiance information received from approximately 3200 pixels. The mean irradiance value within each square was calculated, and the distribution of irradiance values among these 45 squares across the tip-ends was examined. Additionally, the spectral emission was recorded at various regions across each light tip using the integrating sphere with a 4 - mm diameter entrance aperture. Results The localised irradiance distribution was inhomogeneous in all four lights. The irradiance distribution was most uniformly distributed across the PAC tip. Both the irradiance and spectral emission from the poly-LED units were very unevenly distributed. Conclusions Reporting a single irradiance value or a single spectral range to describe the output from a curing light is both imprecise and inappropriate. Instead, an image of both the irradiance distribution and the distribution of the spectral emission across the light tip should be provided. Clinical significance The localised beam irradiance profile at the tip of Dental LCUs is not uniform. Poly-LED units may deliver spectrally inhomogeneous irradiance profiles. Depending on the photoinitiator used in the RBC and the orientation of the LCU over the tooth, this non-uniformity may cause inadequate and inhomogeneous resin polymerisation, leading to poor physical properties, and premature failure of the restoration.
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Irradiance differences in the violet (405 nm) and blue (460 nm) spectral ranges among Dental Light-Curing units.
Journal of esthetic and restorative dentistry : official publication of the American Academy of Esthetic Dentistry ... [et al.], 2010Co-Authors: Richard B. Price, Frederick A Rueggeberg, Daniel Labrie, Christopher M. FelixAbstract:Problem: Previous studies identified nonuniformity in the irradiance at the tip end of a variety of Dental Light-Curing units (LCUs) and correlated those differences with potential clinical implications, but the spectral dependence of the irradiance uniformity has not yet been addressed. Purpose: This study examined the irradiance uniformity across emitting tips of LCUs at two emission wavelengths, 405 and 460 nm. Two broadband emission light units (quartz-tungsten-halogen [QTH] and plasma arc [PAC]), and four commercial light-emitting diode (LED)-type LCUs were examined. Materials and Methods: The spectral radiant power from six LCUs was measured using a laboratory grade spectroradiometer (Ocean Optics, Dunedin, FL, USA). The spatial and spectral characteristics of irradiance across the emitting tips of these light units were recorded through 10-nm wide bandpass filters (centered at 405 nm [violet] or 460 nm [blue]) using a laser beam analyzer (Ophir-Spiricon, Logan, UT, USA). Irradiance distributions were reported using two-dimensional contour and three-dimensional isometric color-coded images. Irradiance uniformity at the tip end was determined using the Top Hat Factor (THF) for each filtered wavelength. Results: Irradiance distributions from the QTH and PAC units were uniformly distributed across the tip end of the light guide, and THF values, measured through the 405 and 460-nm filters, were not significantly different. However, the three polywave LED units delivered non-uniform irradiance distributions with THF values differing significantly between the 405 and 460-nm emission wavelengths for each unit. Areas of nonuniformity were attributed to the locations of the various types of LED chips within the LCUs. Conclusion: All three polywave LED units delivered a nonuniform irradiance distribution across their emitting tip ends at the two important emission wavelengths of 405 nm and 460 nm, whereas the broadband light sources (QTH and PAC) showed no evidence of spectral inhomogeneity at these wavelengths. CLINICAL SIGNIFICANCE Since the rate and extent of polymerization of photo activated restorative materials is highly dependent on delivering radiant energy at specific wavelengths, the nonuniform spectral distribution across the emitting tips of polywave light-emitting diode curing lights may affect the resulting properties of some photocured resins and their potential for long-term clinical success. (J Esthet Restor Dent 22:363–378, 2010)
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Irradiance uniformity and distribution from Dental light curing units.
Journal of Esthetic and Restorative Dentistry, 2010Co-Authors: Richard B. Price, Frederick A Rueggeberg, Daniel Labrie, Christopher M. FelixAbstract:ABSTRACT Problem: The irradiance from Dental Light-Curing units (LCUs) is commonly reported as a single number, but this number does not properly describe the light output. Purpose: This study examined the irradiance uniformity and distribution from a variety of LCUs as well as the effect of different light guides. Materials and Methods: Five LCUs representing quartz-tungsten-halogen, plasma arc, and light emitting diode units were evaluated. One LCU was evaluated using two different light guides (Standard or Turbo style). The total power emitted from each LCU was measured and the irradiance calculated using conventional methods (ICM). In addition, a beam profiler was used to determine the optically active emitting area, the mean irradiance (IBP), the irradiance distribution, and the Top Hat Factor (THF). Five replications were performed for each test and compared using analysis of variance with Fisher's PLSD tests at a pre-set alpha of 0.05. Results: The spatial distribution of the irradiance from LCUs was neither universally symmetrical nor was it uniformly distributed across the tip end. Significant differences in both the emitted power and THF were found among the LCUs. The THF values ranged from a high of 0.74 ± 0.01 to a low of 0.32 ± 0.01. Changing from a standard to a turbo light guide increased the irradiance, but significantly reduced beam homogeneity, reduced the total emitted power, and reduced the optical tip area by 60%. Conclusions: Using different light guides on the same LCU significantly affected the power output, irradiance values, and beam homogeneity. For all LCUs, irradiance values calculated using conventional methods (ICM) did not represent the irradiance distribution across the tip end of the LCU. CLINICAL SIGNIFICANCE Irradiance values calculated using conventional methods assume power uniformity within the beam and do not validly characterize the distribution of the irradiance delivered from Dental light curing units. (J Esthet Restor Dent 22:86–103, 2010)
Daniel Labrie - One of the best experts on this subject based on the ideXlab platform.
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Three-dimensional beam profiling used to characterize Dental Light-Curing units.
Applied optics, 2019Co-Authors: S. M. Juckes, Ivan Kostylev, Richard B. Price, Braden Sullivan, Daniel LabrieAbstract:Two-dimensional (2D) beam profiling is an emerging technique used to characterize the beam homogeneity in Dental Light-Curing units (LCUs). This project developed a method to combine multiple 2D beam profiles that had been measured along the beam path to create a 3D profile of the beam. This allowed a quantitative investigation of beam divergence and homogeneity at different distances from the source. To illustrate the use of this technique, four representative Dental LCUs were measured. In addition, the selected Dental LCUs demonstrated the effects of LCU design, particularly that of fiber optic light guides, on beam quality. The results show the value of a program that can recombine multiple beam profile images made at different distances from the source to create a 3D beam profile of a light beam.
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correlation between the beam profile from a curing light and the microhardness of four resins
Dental Materials, 2014Co-Authors: R B Price, Ivan Kostylev, Frederick A Rueggeberg, Daniel Labrie, Braden Sullivan, John FaheyAbstract:Abstract Objective To demonstrate the effect of localized irradiance and spectral distribution inhomogeneities of one LED-based Dental Light-Curing unit (LCU) on the corresponding microhardness values at the top, and bottom surfaces of four Dental resin-based composites (RBCs), which contained either camphorquinone (CQ) alone or a combination of CQ and monoacylphosphine oxide (TPO) as photoinitiators. Methods Localized irradiance beam profiles from a polywave LED-based LCU were recorded five times using a laser beam analyzer, without and with either a 400 nm or 460 nm narrow bandpass filter placed in front of the camera lens. Five specimens of each of the four RBCs (two containing CQ/TPO and two containing CQ-only) were exposed for 5-, 10-, or 30-s with the light guide directly on the top surface of the RBC. After 24 h, Knoop microhardness values were measured at 45 locations across the top and bottom surfaces of each specimen. Microhardness readings for each RBC surface and exposure time were correlated with localized patterns of the LCU beam profile, measured using the 400 nm and 460 nm bandpass filters. Spearman rank correlation was used to avoid relying on an assumption of a bivariate normal distribution for the KHN and irradiance. Results The local irradiance and spectral emission values were not uniformly distributed across the light tip. There was a strong significant positive correlation with the irradiance beam profile values from the LCU taken through bandpass filters and the microhardness maps of the RBC surfaces exposed for 5 and 10 s. The strength of this correlation decreased with increasing exposure time for the RBCs containing CQ only, and increased for the RBCs containing both CQ and TPO. Conclusions Localized beam and spectral distributions across the tip end of the light guide strongly correlated with corresponding areas of microhardness in both the top and bottom surfaces among four RBCs with different photoinitiator contents. Significance A Light-Curing unit with a highly inhomogeneous light output can adversely affect localized microhardness of resin-based composites and this may be a contributing factor for premature failure of a restoration.
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Localised irradiance distribution found in Dental light curing units
Journal of Dentistry, 2013Co-Authors: Pierre Luc Michaud, Frederick A Rueggeberg, Daniel Labrie, Richard B. Price, Braden SullivanAbstract:Abstract Objective To measure the localised irradiance and wavelength distributions from Dental light curing units (LCUs) and establish a method to characterise their output. Methods Using a laboratory grade integrating sphere spectrometer system (Labsphere and Ocean Optics) the power, irradiance, and spectral emission were measured at the light tips of four LCUs: one plasma-arc (PAC) unit, one single peak blue light-emitting diode (blue-LED) unit, and two polywave LED (poly-LED) units. A beam profiler camera (Ophir Spiricon) was used to record the localised irradiance across the face of the light tips. The irradiance-calibrated beam profile images were then divided into 45 squares, each 1 mm2. Each square contained the irradiance information received from approximately 3200 pixels. The mean irradiance value within each square was calculated, and the distribution of irradiance values among these 45 squares across the tip-ends was examined. Additionally, the spectral emission was recorded at various regions across each light tip using the integrating sphere with a 4 - mm diameter entrance aperture. Results The localised irradiance distribution was inhomogeneous in all four lights. The irradiance distribution was most uniformly distributed across the PAC tip. Both the irradiance and spectral emission from the poly-LED units were very unevenly distributed. Conclusions Reporting a single irradiance value or a single spectral range to describe the output from a curing light is both imprecise and inappropriate. Instead, an image of both the irradiance distribution and the distribution of the spectral emission across the light tip should be provided. Clinical significance The localised beam irradiance profile at the tip of Dental LCUs is not uniform. Poly-LED units may deliver spectrally inhomogeneous irradiance profiles. Depending on the photoinitiator used in the RBC and the orientation of the LCU over the tooth, this non-uniformity may cause inadequate and inhomogeneous resin polymerisation, leading to poor physical properties, and premature failure of the restoration.
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Irradiance differences in the violet (405 nm) and blue (460 nm) spectral ranges among Dental Light-Curing units.
Journal of esthetic and restorative dentistry : official publication of the American Academy of Esthetic Dentistry ... [et al.], 2010Co-Authors: Richard B. Price, Frederick A Rueggeberg, Daniel Labrie, Christopher M. FelixAbstract:Problem: Previous studies identified nonuniformity in the irradiance at the tip end of a variety of Dental Light-Curing units (LCUs) and correlated those differences with potential clinical implications, but the spectral dependence of the irradiance uniformity has not yet been addressed. Purpose: This study examined the irradiance uniformity across emitting tips of LCUs at two emission wavelengths, 405 and 460 nm. Two broadband emission light units (quartz-tungsten-halogen [QTH] and plasma arc [PAC]), and four commercial light-emitting diode (LED)-type LCUs were examined. Materials and Methods: The spectral radiant power from six LCUs was measured using a laboratory grade spectroradiometer (Ocean Optics, Dunedin, FL, USA). The spatial and spectral characteristics of irradiance across the emitting tips of these light units were recorded through 10-nm wide bandpass filters (centered at 405 nm [violet] or 460 nm [blue]) using a laser beam analyzer (Ophir-Spiricon, Logan, UT, USA). Irradiance distributions were reported using two-dimensional contour and three-dimensional isometric color-coded images. Irradiance uniformity at the tip end was determined using the Top Hat Factor (THF) for each filtered wavelength. Results: Irradiance distributions from the QTH and PAC units were uniformly distributed across the tip end of the light guide, and THF values, measured through the 405 and 460-nm filters, were not significantly different. However, the three polywave LED units delivered non-uniform irradiance distributions with THF values differing significantly between the 405 and 460-nm emission wavelengths for each unit. Areas of nonuniformity were attributed to the locations of the various types of LED chips within the LCUs. Conclusion: All three polywave LED units delivered a nonuniform irradiance distribution across their emitting tip ends at the two important emission wavelengths of 405 nm and 460 nm, whereas the broadband light sources (QTH and PAC) showed no evidence of spectral inhomogeneity at these wavelengths. CLINICAL SIGNIFICANCE Since the rate and extent of polymerization of photo activated restorative materials is highly dependent on delivering radiant energy at specific wavelengths, the nonuniform spectral distribution across the emitting tips of polywave light-emitting diode curing lights may affect the resulting properties of some photocured resins and their potential for long-term clinical success. (J Esthet Restor Dent 22:363–378, 2010)
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Irradiance uniformity and distribution from Dental light curing units.
Journal of Esthetic and Restorative Dentistry, 2010Co-Authors: Richard B. Price, Frederick A Rueggeberg, Daniel Labrie, Christopher M. FelixAbstract:ABSTRACT Problem: The irradiance from Dental Light-Curing units (LCUs) is commonly reported as a single number, but this number does not properly describe the light output. Purpose: This study examined the irradiance uniformity and distribution from a variety of LCUs as well as the effect of different light guides. Materials and Methods: Five LCUs representing quartz-tungsten-halogen, plasma arc, and light emitting diode units were evaluated. One LCU was evaluated using two different light guides (Standard or Turbo style). The total power emitted from each LCU was measured and the irradiance calculated using conventional methods (ICM). In addition, a beam profiler was used to determine the optically active emitting area, the mean irradiance (IBP), the irradiance distribution, and the Top Hat Factor (THF). Five replications were performed for each test and compared using analysis of variance with Fisher's PLSD tests at a pre-set alpha of 0.05. Results: The spatial distribution of the irradiance from LCUs was neither universally symmetrical nor was it uniformly distributed across the tip end. Significant differences in both the emitted power and THF were found among the LCUs. The THF values ranged from a high of 0.74 ± 0.01 to a low of 0.32 ± 0.01. Changing from a standard to a turbo light guide increased the irradiance, but significantly reduced beam homogeneity, reduced the total emitted power, and reduced the optical tip area by 60%. Conclusions: Using different light guides on the same LCU significantly affected the power output, irradiance values, and beam homogeneity. For all LCUs, irradiance values calculated using conventional methods (ICM) did not represent the irradiance distribution across the tip end of the LCU. CLINICAL SIGNIFICANCE Irradiance values calculated using conventional methods assume power uniformity within the beam and do not validly characterize the distribution of the irradiance delivered from Dental light curing units. (J Esthet Restor Dent 22:86–103, 2010)
Braden Sullivan - One of the best experts on this subject based on the ideXlab platform.
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Three-dimensional beam profiling used to characterize Dental Light-Curing units.
Applied optics, 2019Co-Authors: S. M. Juckes, Ivan Kostylev, Richard B. Price, Braden Sullivan, Daniel LabrieAbstract:Two-dimensional (2D) beam profiling is an emerging technique used to characterize the beam homogeneity in Dental Light-Curing units (LCUs). This project developed a method to combine multiple 2D beam profiles that had been measured along the beam path to create a 3D profile of the beam. This allowed a quantitative investigation of beam divergence and homogeneity at different distances from the source. To illustrate the use of this technique, four representative Dental LCUs were measured. In addition, the selected Dental LCUs demonstrated the effects of LCU design, particularly that of fiber optic light guides, on beam quality. The results show the value of a program that can recombine multiple beam profile images made at different distances from the source to create a 3D beam profile of a light beam.
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correlation between the beam profile from a curing light and the microhardness of four resins
Dental Materials, 2014Co-Authors: R B Price, Ivan Kostylev, Frederick A Rueggeberg, Daniel Labrie, Braden Sullivan, John FaheyAbstract:Abstract Objective To demonstrate the effect of localized irradiance and spectral distribution inhomogeneities of one LED-based Dental Light-Curing unit (LCU) on the corresponding microhardness values at the top, and bottom surfaces of four Dental resin-based composites (RBCs), which contained either camphorquinone (CQ) alone or a combination of CQ and monoacylphosphine oxide (TPO) as photoinitiators. Methods Localized irradiance beam profiles from a polywave LED-based LCU were recorded five times using a laser beam analyzer, without and with either a 400 nm or 460 nm narrow bandpass filter placed in front of the camera lens. Five specimens of each of the four RBCs (two containing CQ/TPO and two containing CQ-only) were exposed for 5-, 10-, or 30-s with the light guide directly on the top surface of the RBC. After 24 h, Knoop microhardness values were measured at 45 locations across the top and bottom surfaces of each specimen. Microhardness readings for each RBC surface and exposure time were correlated with localized patterns of the LCU beam profile, measured using the 400 nm and 460 nm bandpass filters. Spearman rank correlation was used to avoid relying on an assumption of a bivariate normal distribution for the KHN and irradiance. Results The local irradiance and spectral emission values were not uniformly distributed across the light tip. There was a strong significant positive correlation with the irradiance beam profile values from the LCU taken through bandpass filters and the microhardness maps of the RBC surfaces exposed for 5 and 10 s. The strength of this correlation decreased with increasing exposure time for the RBCs containing CQ only, and increased for the RBCs containing both CQ and TPO. Conclusions Localized beam and spectral distributions across the tip end of the light guide strongly correlated with corresponding areas of microhardness in both the top and bottom surfaces among four RBCs with different photoinitiator contents. Significance A Light-Curing unit with a highly inhomogeneous light output can adversely affect localized microhardness of resin-based composites and this may be a contributing factor for premature failure of a restoration.
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Localised irradiance distribution found in Dental light curing units
Journal of Dentistry, 2013Co-Authors: Pierre Luc Michaud, Frederick A Rueggeberg, Daniel Labrie, Richard B. Price, Braden SullivanAbstract:Abstract Objective To measure the localised irradiance and wavelength distributions from Dental light curing units (LCUs) and establish a method to characterise their output. Methods Using a laboratory grade integrating sphere spectrometer system (Labsphere and Ocean Optics) the power, irradiance, and spectral emission were measured at the light tips of four LCUs: one plasma-arc (PAC) unit, one single peak blue light-emitting diode (blue-LED) unit, and two polywave LED (poly-LED) units. A beam profiler camera (Ophir Spiricon) was used to record the localised irradiance across the face of the light tips. The irradiance-calibrated beam profile images were then divided into 45 squares, each 1 mm2. Each square contained the irradiance information received from approximately 3200 pixels. The mean irradiance value within each square was calculated, and the distribution of irradiance values among these 45 squares across the tip-ends was examined. Additionally, the spectral emission was recorded at various regions across each light tip using the integrating sphere with a 4 - mm diameter entrance aperture. Results The localised irradiance distribution was inhomogeneous in all four lights. The irradiance distribution was most uniformly distributed across the PAC tip. Both the irradiance and spectral emission from the poly-LED units were very unevenly distributed. Conclusions Reporting a single irradiance value or a single spectral range to describe the output from a curing light is both imprecise and inappropriate. Instead, an image of both the irradiance distribution and the distribution of the spectral emission across the light tip should be provided. Clinical significance The localised beam irradiance profile at the tip of Dental LCUs is not uniform. Poly-LED units may deliver spectrally inhomogeneous irradiance profiles. Depending on the photoinitiator used in the RBC and the orientation of the LCU over the tooth, this non-uniformity may cause inadequate and inhomogeneous resin polymerisation, leading to poor physical properties, and premature failure of the restoration.
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correlation between the beam profile from a curing light and the microhardness of four resins
Dental Materials, 2014Co-Authors: R B Price, Ivan Kostylev, Frederick A Rueggeberg, Daniel Labrie, Braden Sullivan, John FaheyAbstract:Abstract Objective To demonstrate the effect of localized irradiance and spectral distribution inhomogeneities of one LED-based Dental Light-Curing unit (LCU) on the corresponding microhardness values at the top, and bottom surfaces of four Dental resin-based composites (RBCs), which contained either camphorquinone (CQ) alone or a combination of CQ and monoacylphosphine oxide (TPO) as photoinitiators. Methods Localized irradiance beam profiles from a polywave LED-based LCU were recorded five times using a laser beam analyzer, without and with either a 400 nm or 460 nm narrow bandpass filter placed in front of the camera lens. Five specimens of each of the four RBCs (two containing CQ/TPO and two containing CQ-only) were exposed for 5-, 10-, or 30-s with the light guide directly on the top surface of the RBC. After 24 h, Knoop microhardness values were measured at 45 locations across the top and bottom surfaces of each specimen. Microhardness readings for each RBC surface and exposure time were correlated with localized patterns of the LCU beam profile, measured using the 400 nm and 460 nm bandpass filters. Spearman rank correlation was used to avoid relying on an assumption of a bivariate normal distribution for the KHN and irradiance. Results The local irradiance and spectral emission values were not uniformly distributed across the light tip. There was a strong significant positive correlation with the irradiance beam profile values from the LCU taken through bandpass filters and the microhardness maps of the RBC surfaces exposed for 5 and 10 s. The strength of this correlation decreased with increasing exposure time for the RBCs containing CQ only, and increased for the RBCs containing both CQ and TPO. Conclusions Localized beam and spectral distributions across the tip end of the light guide strongly correlated with corresponding areas of microhardness in both the top and bottom surfaces among four RBCs with different photoinitiator contents. Significance A Light-Curing unit with a highly inhomogeneous light output can adversely affect localized microhardness of resin-based composites and this may be a contributing factor for premature failure of a restoration.