Microstructural changes of human enamel surfaces by brushing with and without dentifrice containing abrasive

Area of Science:

• Dental research
• Oral hygiene science
• Biomaterials science

Background:

• Tooth enamel is susceptible to wear and abrasion.
• The role of dentifrice abrasives in enamel modification is debated.
• Saliva's protective properties in oral health are significant.

Purpose of the Study:

• To investigate the effects of brushing with and without abrasive dentifrice on human enamel.
• To compare the surface changes induced by different brushing conditions.
• To assess the potential protective or detrimental impacts on enamel integrity.

Main Methods:

• Human enamel samples with engraved scratches were exposed to the oral cavities of three subjects for eight weeks.
• Toothbrushing was performed with and without abrasive-containing dentifrice.
• Surface changes were analyzed using scanning electron and scanning laser microscopy.

Main Results:

• Brushing without dentifrice led to the formation of an organic-mineral pellicle, protecting existing scratches and covering the surface.
• Brushing with abrasive dentifrice resulted in abrasion, disappearance of small scratches, expansion of large ones, and the appearance of microwear, exposing prism structures.
• The abrasive action of dentifrice created surface roughness.

Conclusions:

• Toothbrushing with saliva alone (no dentifrice) induces a protective organic-mineral membrane that may enhance enamel resistance to caries.
• Abrasive-containing dentifrices cause enamel abrasion and microwear, potentially increasing surface roughness and contributing to dental plaque formation.