LED light attenuation through human dentin: a first step toward pulp photobiomodulation after cavity preparation

Area of Science:

• Biomaterials Science
• Dental Materials Science
• Optical Physics

Background:

• Understanding light penetration through dentin is crucial for dental procedures, particularly those involving light-cured materials and intraoral devices.
• Light-emitting diode (LED) technology offers various wavelengths for dental applications, but their efficacy can be influenced by the optical properties of tooth structure.

Purpose of the Study:

• To quantify the attenuation of LED light across three distinct wavelengths (blue, red, and infrared) as it passes through human dentin of varying thicknesses.
• To simulate the conditions of different cavity preparation depths and assess the impact on light transmission.

Main Methods:

• Human molar dentin discs (0.2, 0.5, and 1.0 mm thick) were prepared.
• LED light at 450±10 nm (blue), 630±10 nm (red), and 850±10 nm (infrared) was used to illuminate the dentin specimens.
• Light transmittance was measured using spectrophotometry to determine light attenuation percentages.

Main Results:

• Light attenuation varied significantly with dentin thickness and wavelength, ranging from 39.3% to 69.9%.
• Blue light (450 nm) exhibited the highest attenuation (49.3%–69.9%), followed by red light (42.9%–58.5%), and infrared light (39.3%–46.8%).
• Higher wavelengths generally showed increased transmittance, with the most significant variation observed at the thinnest dentin (0.2 mm).

Conclusions:

• All tested LED wavelengths can penetrate human dentin, though with varying degrees of attenuation.
• Dentin thickness and light wavelength are critical factors influencing LED light penetration and power loss.
• These findings are essential for optimizing light delivery in dental treatments requiring light transmission through dentin.