title: The relationship of dental extrinsic stains with the concentration of trace elements in water sources in a district of Nepal.
abstract: OBJECTIVE
  To assess the relationship of dental extrinsic stains (DES) with levels of trace elements in drinking water sources.
  
  
  METHODS
  A cross-sectional study among the population of Madesha VDC. A sample of 551 residents aged between 4 years and above was examined. A questionnaire was prepared to assess the dietary habits, oral hygiene practices, age, period of residency (POR), followed by clinical examination regarding the presence or absence of DES. Water samples were collected and sent for analysis by AAS method for trace elements.
  
  
  RESULTS
  The prevalence of DES was 39%. Twenty-eight water samples had Fe levels that exceeded permissible levels and all samples were negative for other trace elements. Stains were associated with POR and levels of Fe in water (P value < 0.001). There was a positive correlation by ward of Fe levels and stain distribution.
  
  
  CONCLUSIONS
  The results revealed an association between DES with age, POR, and Fe levels in water. The positive correlation between stain distribution by ward and levels of Fe in water indicated the causative role of Fe in stains.
authors.affiliation: BP Koirala Institute of Health Sciences, Dharan, Nepal.
authors.forename: K
authors.initials: K
authors.lastname: Pushpanjali
authors.forename: Sudhanshu Sharma
authors.initials: SS
authors.lastname: Khanal
authors.forename: Surya Raj
authors.initials: SR
authors.lastname: Niraula
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D006801:Humans; D007501:Iron / Q000009:adverse effects* / Q000032:analysis; D008875:Middle Aged; D009390:Nepal / Q000453:epidemiology; D015995:Prevalence; D014075:Tooth Discoloration / Q000139:chemically induced* / Q000453:epidemiology*; D014131:Trace Elements / Q000009:adverse effects* / Q000032:analysis; D014867:Water / Q000737:chemistry*; D014881:Water Supply / Q000032:analysis*
chemical_list: D014131:Trace Elements; D014867:Water; D007501:Iron