Human enamel nanohardness, elastic modulus and surface integrity after beverage contact

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Surface Science

Background:

• Dental enamel, the hardest tissue in the human body, is susceptible to degradation from acidic dietary components.
• The increasing consumption of acidic beverages poses a significant risk to dental health, potentially altering enamel's mechanical properties.

Purpose of the Study:

• To evaluate the impact of common acidic beverages (carbonated drink, orange juice) on the nanohardness, elastic modulus, and surface roughness of human enamel.
• To compare the erosive potential of a carbonated drink versus orange juice on dental enamel.

Main Methods:

• Human enamel samples were exposed to a carbonated drink, orange juice, or tap water (control) for 5 weeks.
• Surface roughness was measured using a profilometer.
• Nanohardness and elastic modulus were determined using nanoindentation.
• Beverage pH was monitored throughout the study period.

Main Results:

• Exposure to the carbonated drink led to significant decreases in enamel elastic modulus (111.6 to 62.3 GPa) and nanohardness (4.62 to 1.28 GPa), with increased roughness (5.30 to 6.86 µm).
• Orange juice also reduced enamel properties (elastic modulus: 115.15 to 92.11 GPa; nanohardness: 5.54 to 3.18 GPa) and increased roughness (5.26 to 6.73 µm), but to a lesser extent than the carbonated drink.
• Tap water (control) showed minimal changes in enamel properties and roughness.

Conclusions:

• Acidic beverages, particularly carbonated drinks, significantly degrade the mechanical integrity (nanohardness, elastic modulus) and increase the surface roughness of human enamel.
• Despite a similar acidic trend, orange juice exhibited a less detrimental effect on enamel properties compared to the carbonated beverage.
• These findings highlight the importance of beverage choice in maintaining dental enamel health and preventing erosion.