Emissivity evaluation of human enamel and dentin

Area of Science:

• Biomedical Engineering
• Dental Materials Science
• Thermal Imaging

Background:

• Non-contact infrared imaging requires accurate emissivity for human enamel and dentin temperature measurements.
• Emissivity, influenced by tissue properties, varies across literature and necessitates precise evaluation.
• Understanding emissivity is crucial for dental thermal safety assessments and diagnostic applications.

Purpose of the Study:

• To determine the emissivity of sound human enamel and dentin surfaces (external and internal).
• To assess the emissivity of natural enamel and dentin caries.
• To establish a reliable methodology for emissivity acquisition in dental thermal imaging.

Main Methods:

• Fourteen human molars were analyzed in a controlled thermal chamber.
• Infrared thermography (FLIR SC305) captured temperature changes of enamel and dentin samples.
• A reference material with known emissivity (0.96) was used for calibration.

Main Results:

• Sound external enamel: 0.96, internal enamel: 0.97.
• Sound internal crown dentin: 0.94, internal root dentin: 0.93, surface root dentin: 0.84.
• Caries lesions showed significantly lower emissivity: internal enamel 0.82, internal crown dentin 0.73.

Conclusions:

• Sound enamel exhibits higher emissivity than sound dentin, with dentin values decreasing from crown to root.
• Dental caries markedly reduces enamel and dentin emissivity.
• This methodology enhances emissivity data for thermal imaging, aiding dental procedure safety analysis and potentially diagnosing caries.