title: Spectrophotometric Evaluation of Colour Stability of Nano Hybrid Composite Resin in Commonly Used Food Colourants in Asian Countries.
abstract: BACKGROUND
  There is growing interest in colour stability of aesthetic restorations. So far few studies have been reported.
  
  
  OBJECTIVE
  This study was designed to investigate the effects of different common food colourants i.e., Turmeric and Carmoisine (orange red dye) consumed by patients in Asian countries on a recent nano hybrid composite resin.
  
  
  METHODS
  A total of sixty disk shaped specimens measuring 10 mm in diameter and 2 mm in thickness were prepared. The samples were divided into two groups {Z 100 (Dental restorative composite) Filtek Z 250 XT (Nano hybrid universal restorative)}. Baseline colour measurement of all specimens were made using reflectance spectrophotometer with CIE L*a*b* system. Specimens were immersed in artificial saliva and different experimental solutions containing food colourants (carmoisine solution and turmeric solution) for three hours per day at 37°C. Colour measurements were made after 15 days. Colour difference (ΔE*) was calculated. Mean values were compared by one-way analysis of variance (ANOVA). Multiple range test by Tukey Post-hoc test procedure was employed to identify the significant groups at 5% level.
  
  
  RESULTS
  Z 100 showed minimum staining capacity when compared to Z 250 XT in both the colourant solutions.
  
  
  CONCLUSIONS
  The nanohybrid composite resin containing TEGDMA showed significant colour change when compared to that of microhybrid composite resin as a result of staining in turmeric and carmoisine solution.
authors.affiliation: Assistant Professor, Department of Conservative Dentistry and Endodontics, GSL Dental College , Rajahmundry, Andhra Pradesh, India .
authors.forename: Jyothi
authors.initials: J
authors.lastname: Chittem
authors.affiliation: Professor and Head, Department of Conservative Dentistry and Endodontics, Vishnu Dental College , Bhimavaram, Andhra Pradesh, India .
authors.forename: Girija S
authors.initials: GS
authors.lastname: Sajjan
authors.affiliation: Professor, Department of Conservative Dentistry and Endodontics, Vishnu Dental College , Bhimavaram, Andhra Pradesh, India .
authors.forename: Madhu
authors.initials: M
authors.lastname: Varma Kanumuri
keywords: Food colour; Nanotechnology; Resin composite; Spectrophotometry