IADR Abstract Archives
Can 4mm Sensors Accurately Measure Spectral Irradiance of Multi-diode/Wavelength LCUs
Objectives: To compare the effectiveness of 2 MARC Resin Calibrators (RC) for measurement of multi-diode/wavelength, light curing units (LCUs) as a function of beam profile, distance and wavelength.
Methods: Duplicate LCUs (Bluephase Style: BS; Ivoclar Vivadent and a prototype Scanwave: PS; Satelec, Acteon; Modes, CQ: 440nm/480nm, PP: 440nm/465nm, TP: 440nm/480nm) with original multi-fibred tips (OT) and homogenising tips (HT) with diameters, BS=10mm, PS=7.5mm were used. Beam profile (distance=0mm) was measured using a CCD camera for each LCU/tip combination. Narrowpass filters (405nm/460nm, THORLABS) were used to establish the beam profile of BS LCU. The RC’s (top sensor) was used to assess spectral irradiance as a function of tip position (central and 90o, 1 mm offsets) distance (0mm, 2mm & 6mm). Reduction ratio relative to central position was calculated at each distance. Differences were assessed with multivariate analysis of variance.
Results: Two MARC RCs correlated with HT but not with OT for BS (central position, 0mm distance, 2% and 14% difference respectively). Non-homogenous beam profiles were obtained with OT compared to HT for both LCUs. Both LCUs exhibited tip and position dependent differences in spectral irradiance which declined with distance; the decline was less for BS (P<0.05) and was generally lower for the HT compared to OT for both LCUs. At 0mm distance, irradiance difference at the different positions was lower with BS HT than OT (<3.6% and up-to 87.4% respectively); at 6mm distance (central position), HT irradiance exceeded corresponding 0mm irradiance (P<0.05). For PS, significantly highest irradiance change was measured between the OT and HT at ‘south’ positions for TP mode, ‘east’ for PP mode, and ‘north’ for CQ mode (P<0.05).
Conclusions: 4mm sensors only partially capture dental LCU light output which have tips greater than 4mm diameter. Tip positioning relative to the sensor is critical due to variations in spectral irradiance across multi-diode/wavelength LCUs.
Methods: Duplicate LCUs (Bluephase Style: BS; Ivoclar Vivadent and a prototype Scanwave: PS; Satelec, Acteon; Modes, CQ: 440nm/480nm, PP: 440nm/465nm, TP: 440nm/480nm) with original multi-fibred tips (OT) and homogenising tips (HT) with diameters, BS=10mm, PS=7.5mm were used. Beam profile (distance=0mm) was measured using a CCD camera for each LCU/tip combination. Narrowpass filters (405nm/460nm, THORLABS) were used to establish the beam profile of BS LCU. The RC’s (top sensor) was used to assess spectral irradiance as a function of tip position (central and 90o, 1 mm offsets) distance (0mm, 2mm & 6mm). Reduction ratio relative to central position was calculated at each distance. Differences were assessed with multivariate analysis of variance.
Results: Two MARC RCs correlated with HT but not with OT for BS (central position, 0mm distance, 2% and 14% difference respectively). Non-homogenous beam profiles were obtained with OT compared to HT for both LCUs. Both LCUs exhibited tip and position dependent differences in spectral irradiance which declined with distance; the decline was less for BS (P<0.05) and was generally lower for the HT compared to OT for both LCUs. At 0mm distance, irradiance difference at the different positions was lower with BS HT than OT (<3.6% and up-to 87.4% respectively); at 6mm distance (central position), HT irradiance exceeded corresponding 0mm irradiance (P<0.05). For PS, significantly highest irradiance change was measured between the OT and HT at ‘south’ positions for TP mode, ‘east’ for PP mode, and ‘north’ for CQ mode (P<0.05).
Conclusions: 4mm sensors only partially capture dental LCU light output which have tips greater than 4mm diameter. Tip positioning relative to the sensor is critical due to variations in spectral irradiance across multi-diode/wavelength LCUs.