Protective Barriers and Radiant Exposure Delivered from Light-curing Units
To evaluate the influence of different protective barriers as a function of the photoactivation distances on the radiant exposure of several light-curing units (LCU). The influence of the protective barriers on the degree of conversion of an adhesive resin was also evaluated. Five LCUs were evaluated: Valo Cordless—used in standard mode (Ultradent, South Jordan, USA); Radii-cal—used in continuous mode (SDI, Bayswater, AU); Emitter D—used in continuous mode (Schuster, Santa Maria, BR); Bluephase N—used in high-intensity mode (Ivoclar Vivadent, Schaan, LI); and Rainbow Curing Light—used in continuous mode (Axdent, Guangdong, CN). For each LCU, radiant exposure was measured with a spectrometer (MARC Resin Calibrator) using three different protective barriers (low-density polyethylene, polyvinyl chloride, or Radii-cal barrier sleeves) and five photoactivation distances (0, 2, 5, 10, and 20 mm). The degree of conversion of an adhesive resin (Adper Scotchbond Multi-Purpose, 3M ESPE, St. Paul, USA) was measured through Fourier-transform infrared spectroscopy. The translucency parameter of protective barriers was measured with a spectrophotometer. For all statistical tests, a significance level of α = 0.05 was set. For all LCUs tested, radiant exposure was found to be significantly influenced by both protective barriers and curing distance (p≤0.001). In general terms, all the protective barriers significantly decreased the radiant exposure. Radii-cal barrier sleeves were the protective barrier that most decreased the radiant exposure. Irrespective of the protective barrier used, none of the LCU equipment reached the required minimum radiant exposure of 16 J/cm2 at 10 mm of curing distance. The degree of conversion was not effected by either LCU or a protective barrier (p≥0.211). Protective barriers and photoactivation distance reduced the radiant exposure emitted by different LCUs.SUMMARY
Objective
Methods
Results
Conclusions
Mean (%) and standard deviation of translucency parameter for each barrier protection. Different letters show statistically significant difference (p<0.001).
Irradiance emitted by light curing unit Valo Cordless, exposure time 20 seconds, at distances of 0, 2, 5, 10, and 20 mm with different barriers: no barrier (NB), polyvinyl chloride (PVC); polyethylene (P); barrier sleeves SDI (BS).
Irradiance emitted by light curing unit Bluephase N, exposure time 20 seconds, at distances of 0, 2, 5, 10, and 20 mm with different barriers: no barrier (NB), polyvinyl chloride (PVC); polyethylene (P); barrier sleeves SDI (BS).
Irradiance emitted by light curing unit Radii-cal, exposure time 20 seconds, at distances of 0, 2, 5, 10, and 20 mm with different barriers: no barrier (NB), polyvinyl chloride (PVC); polyethylene (P); barrier sleeves SDI (BS).
Irradiance emitted by light curing unit Emitter D, exposure time 20 seconds, at distances of 0, 2, 5, 10, and 20 mm with different barriers: no barrier (NB), polyvinyl chloride (PVC); polyethylene (P); barrier sleeves SDI (BS).
Irradiance emitted by Rainbow light curing, exposure time 20 seconds, at distances of 0, 2, 5, 10, and 20 mm with different barriers: no barrier (NB), polyvinyl chloride (PVC); polyethylene (P); barrier sleeves SDI (BS).
Contributor Notes
Clinical Relevance
Placement of protective barriers over the light guide did not affect the degree of conversion of the material, therefore, it can be recommended for use in dental clinical practice.