Microstructural features of carious human enamel imaged with back-scattered electrons

Area of Science:

• Dental research
• Materials science
• Microscopy techniques

Background:

• Dental caries involves complex mineral changes within tooth enamel.
• Understanding these changes at a high resolution is crucial for early diagnosis and treatment.
• Existing imaging techniques have limitations in visualizing mineral density variations.

Purpose of the Study:

• To develop and apply back-scattered electron (BE) scanning electron microscopy (SEM) for mineral density imaging of carious enamel.
• To visualize and characterize mineral loss and gain patterns in both artificial and natural dental caries.
• To assess the effectiveness of BE-SEM for detailed analysis of enamel microstructure during demineralization.

Main Methods:

• Utilized scanning electron microscopy (SEM) with a 4-quadrant back-scattered electron (BE) detector.
• Examined polished surfaces of artificially-softened and naturally-carious (white spot) enamel at 10-30 kV.
• Prepared enamel samples parallel and perpendicular to the natural surface for varied imaging perspectives.

Main Results:

• BE-SEM produced high-resolution mineral density images of carious enamel.
• Observed mineral loss from prism cores and interprismatic regions, with a mineral-rich rim.
• Identified mineral-rich bands at prism margins and widened prism junctions at lesion fronts.
• Detailed visualization of cross-striations and striae of Retzius in natural lesions.

Conclusions:

• Back-scattered electron (BE) microscopy is an effective, high-resolution method for imaging mineral density in carious enamel.
• The technique provides detailed insights into mineral distribution during caries progression.
• BE-SEM offers a valuable tool for studying demineralization and remineralization processes in dental research.