In Vitro Analysis of Enamel Abrasion Using a Novel Manual Nano-Bristle Toothbrush: An Atomic Force Microscopy Study.

INTRODUCTION

To evaluate the enamel abrasion effects of soft, ultra-soft, and nano-bristle toothbrushes using atomic force microscopy (AFM) to guide toothbrush selection for optimal enamel preservation.

METHODS

This in vitro study involved 45 extracted human teeth (central and lateral incisors), randomly assigned to three groups (n=15 each): Group I (nano-bristle), Group II (ultra-soft bristle), and Group III (soft bristle). Each specimen underwent 10,000 brushing cycles with a standardized 2 N force to simulate one year of brushing. A slurry of commercially available toothpaste mixed with saline was applied, and brushing was performed with a mechanical brushing simulator. AFM analysis measured enamel surface roughness before and after brushing.

RESULTS

Nano-bristle toothbrushes caused a minimal increase in surface roughness (mean change: 4 nm; p = 0.001), significantly less than the increases seen with soft (mean change: 14.08 nm; p = 0.001) and ultra-soft (mean change: 14.86 nm; p = 0.001) bristle toothbrushes. AFM analysis confirmed that both soft and ultra-soft bristles caused greater enamel abrasion compared to nano-bristles, with no significant difference between soft and ultra-soft bristle groups.

CONCLUSION

Nano-bristle toothbrushes demonstrated the least enamel abrasion in this study, suggesting they may provide a gentle alternative for preserving enamel integrity.