Frictional coefficient during flossing of teeth

Area of Science:

• Dental Mechanics
• Biomaterials Science
• Oral Hygiene

Background:

• The friction coefficient (μ) between dental floss and teeth is crucial for understanding potential tooth surface damage and flossing efficacy.
• Groove formation at the cementoenamel junction (CEJ) is a debated topic potentially linked to flossing mechanics.

Purpose of the Study:

• To develop a method for measuring frictional forces and the coefficient of friction (μ) during dental flossing.
• To investigate the influence of surface characteristics, moisture, and contact angulation on the friction between dental floss and tooth-like surfaces.

Main Methods:

• An in-vitro study measured the friction coefficient (μ) using the Capstan equation under controlled load (100g).
• Tests involved waxed and unwaxed nylon floss on enamel, dentine, and glass rods under dry and wet conditions.
• Scanning electron microscopy (SEM) analyzed floss deterioration after use.

Main Results:

• The friction coefficient (μ) varied significantly with surface type and moisture: highest on smooth glass (0.42), lowest on dentine (0.18).
• Waxed floss exhibited higher friction against dry surfaces and showed greater deterioration, especially on dry enamel and glass rods.
• No correlation was found between friction coefficient (μ) and dental floss contact angulation.

Conclusions:

• Frictional forces during flossing are significantly influenced by surface roughness and moisture levels.
• Contact angulation does not appear to affect the friction coefficient (μ) between dental floss and tooth surfaces.
• The findings underscore the importance of considering material wear and potential tooth surface interactions in clinical flossing applications.