title: Human enamel nanohardness, elastic modulus and surface integrity after beverage contact.
abstract: This study evaluated nanohardness, elastic modulus and surface roughness of human enamel after contact with citric beverages. Human enamel samples were assigned to 3 groups according to the type of beverage used: carbonated drink, orange juice and tap water (control). Surface roughness was assessed using a profilometer, and nanohardness and elastic modulus were recorded using a nanoindenter. The pH of the beverages was measured before and after citric contact during 5 weeks. Means(SD) were as follows: Carbonated drink: elastic modulus decreased from 111.6(14.5) to 62.3(10.3) GPa, nanohardness decreased from 4.62(0.67) to 1.28(0.46) GPa, roughness increased from 5.30(2.39) to 6.86(2.56) microm, and the pH changed from 2.69(0.35) to 2.29(0.24); Orange juice: elastic modulus changed from 115.15(12.94) to 92.11 GPa (13.83), nanohardness from 5.54(1.48) to 3.18 GPa (0.64), roughness from 5.26(2.27) to 6.73(2.25) microm, and pH from 3.46(0.20) to 3.03(0.14); Tap water (control): elastic modulus changed from 117.87(22.3) to 107.91(20.05) GPa, nanohardness from 4.35(1.66) to 4.28(0.93) GPa, roughness from 5.76(3.11) to 6.11(2.65) microm, and pH from 7.97(0.28) to 8.11(0.21). In conclusion, soft drink exposure caused a significant decrease in nanohardness and elastic modulus. The pH of the soft drink was more acidic from 5 degrees C to 37 degrees C. Orange juice showed a similar trend but, surprisingly, it had less effect on hardness, elastic modulus and roughness of enamel than the carbonated drink.
authors.affiliation: Restorative and Prosthetic Dentistry, Ohio State University, Columbus, Ohio, USA. machado.6@osu.edu
authors.forename: Camilo
authors.initials: C
authors.lastname: Machado
authors.forename: William
authors.initials: W
authors.lastname: Lacefield
authors.forename: Aaron
authors.initials: A
authors.lastname: Catledge
mesh_terms: D001628:Beverages / Q000009:adverse effects; D002253:Carbonated Beverages / Q000009:adverse effects; D002957:Citrus; D003743:Dental Enamel / Q000648:ultrastructure*; D055119:Elastic Modulus; D006244:Hardness; D006801:Humans; D006863:Hydrogen-Ion Concentration; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014867:Water
chemical_list: D014867:Water