The subsurface lesion in erosive tooth wear

Area of Science:

• Dental materials science
• Biomaterials engineering
• Tribology

Background:

• Tooth enamel is susceptible to wear from mechanical and chemical challenges.
• Understanding enamel's response to combined wear is crucial for preventing tooth tissue loss.
• Surface treatments like polishing can alter enamel's wear resistance.

Purpose of the Study:

• To compare surface changes on natural and polished human enamel under combined mechanical (abrasion) and chemical (erosion) wear.
• To investigate the depth and nature of subsurface alterations in enamel subjected to different wear regimens.
• To evaluate the protective effect of natural enamel surface integrity against wear.

Main Methods:

• Human enamel samples (natural and polished) were subjected to erosion (citric acid), abrasion, or combined erosion-abrasion.
• Wear was quantified using a non-contact profilometer to measure step height.
• Surface morphology and subsurface changes were analyzed using Scanning Electron Microscopy (SEM).

Main Results:

• Polished enamel exhibited greater wear (step height) than natural enamel under erosion-only conditions.
• Combined erosion and abrasion led to significant subsurface changes in natural enamel, reaching up to 50 µm.
• SEM revealed shallow subsurface layers for polished and naturally eroded enamel, contrasting with deeper lesions in eroded/abraded natural enamel.

Conclusions:

• Natural enamel demonstrates superior resistance to erosion alone compared to polished enamel.
• Combined erosion and abrasion significantly increases wear and subsurface damage in natural enamel.
• The findings suggest that combined wear mechanisms can accelerate tooth tissue loss, particularly affecting natural enamel surfaces.