Robust spectrometer-based methods for characterizing radiant exitance of dental LED light curing units.

Area of Science:

• Dental Materials Science
• Optical Metrology
• Biomedical Engineering

Background:

• Accurate measurement of dental light curing unit (LCU) output is crucial for effective polymerization.
• Existing measurement methods, particularly thermopiles, may exhibit inconsistencies and limitations.

Purpose of the Study:

• To evaluate a portable spectrometer instrument for measuring dental LCU light output against a gold standard.
• To assess the consistency of light output measurements using multiple laboratory-grade thermopile instruments.

Main Methods:

• Measured light output of eight dental LCUs using two spectrometer systems and three thermopile instruments.
• Compared portable spectrometer measurements with a benchtop Integrating Sphere system.
• Recorded beam profile images to assess spatial and spectral uniformity.

Main Results:

• Portable spectrometer measurements closely matched the gold standard Integrating Sphere apparatus.
• Significant radiant exitance differences were observed between thermopiles.
• Thermopile measurements were significantly influenced by light source to sensor distance, highlighting limitations for absolute measurements.
• Polywave LCUs showed spectral heterogeneity in their beam profiles.

Conclusions:

• Spectrometer-based methods overcome the limitations of thermopile-based techniques for LCU light output measurement.
• Spectrometer measurements align with the intended accuracy of ISO 10650 standards.
• Portable spectrometers offer a reliable alternative for assessing dental LCU performance.