title: The effect of different beverages on surface hardness of nanohybrid resin composite and giomer.
abstract: OBJECTIVE
  To investigate the effects of five beverages (apple cider, orange juice, Coca-Cola, coffee, and beer) on microhardness and surface characteristic changes of nanohybrid resin composite and giomer.
  
  
  METHODS
  Ninety-three specimens of each resin composite and giomer were prepared. Before immersion, baseline data of Vicker's microhardness was recorded and surface characteristics were examined using scanning electron microscopy (SEM). Five groups of discs (n = 18) were alternately immersed in 25 mL of each beverage for 5 s and in 25 mL of artificial saliva for 5 s for 10 cycles. Specimens were then stored in artificial saliva for 24 h. This process was repeated for 28 days. After immersion, specimens were evaluated and data were analyzed by two-way repeated analysis of variance (ANOVA), Tukey's honestly significant difference (HSD), and a t-test (α = 0.05).
  
  
  RESULTS
  Microhardness of all groups significantly decreased after being immersed in the tested beverages (P < 0.05). SEM photomicrographs presented surface degradation of all groups.
  
  
  CONCLUSIONS
  The effect of these beverages on the surface of both restorative materials also depended upon the exposure time and chemical composition of the restorative materials and beverages.
authors.affiliation: Department of Conservative Dentistry, Faculty of Dentistry, Prince of Songkla University, Hat Yai, Songkhla, Thailand.
authors.forename: Saijai
authors.initials: S
authors.lastname: Tanthanuch
authors.affiliation: Maxillofacial Prosthodontics Rehabilitation Research Unit, Faculty of Dentistry, Prince of Songkla University, Hat Yai, Songkhla, Thailand.
authors.forename: Boonlert
authors.initials: B
authors.lastname: Kukiattrakoon
authors.affiliation: Department of Conservative Dentistry, Faculty of Dentistry, Prince of Songkla University, Hat Yai, Songkhla, Thailand.
authors.forename: Chantima
authors.initials: C
authors.lastname: Siriporananon
authors.affiliation: Department of Conservative Dentistry, Faculty of Dentistry, Prince of Songkla University, Hat Yai, Songkhla, Thailand.
authors.forename: Nawanda
authors.initials: N
authors.lastname: Ornprasert
authors.affiliation: Department of Conservative Dentistry, Faculty of Dentistry, Prince of Songkla University, Hat Yai, Songkhla, Thailand.
authors.forename: Wathu
authors.initials: W
authors.lastname: Mettasitthikorn
authors.affiliation: Department of Conservative Dentistry, Faculty of Dentistry, Prince of Songkla University, Hat Yai, Songkhla, Thailand.
authors.forename: Salinla
authors.initials: S
authors.lastname: Likhitpreeda
authors.affiliation: Department of Conservative Dentistry, Faculty of Dentistry, Prince of Songkla University, Hat Yai, Songkhla, Thailand.
authors.forename: Sulawan
authors.initials: S
authors.lastname: Waewsanga
keywords: Beverage; giomer; microhardness; resin composite