Measuring the validity of two in-office water test kits

Joseph A. Bartoloni, Nuala B. Porteous, Lee Ann Zarzabal

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


Background. The authors conducted a study to determine the validity of two commercially available in-office water test kits compared with a spread plate technique using the gold standard dehydrated culture medium R2A agar for monitoring the quality of dental treatment water. Methods. Over a 12-week period, one author monitored nine dental units in a dental school that each were equipped with an independent water reservoir. The author collected 351 split samples, cultured them using three test methods, counted bacterial colonies manually and assessed validity using two cutoff values: ≤ 200 colony-forming units per milliliter (CFU/mL) (an American Dental Association goal) and ≤ 500 CFU/mL (a Centers for Disease Control and Prevention [CDC] recommendation and a U.S. Environmental Protection Agency [EPA] mandate). Results. Of the 351 split samples processed, the in-office test kits' accuracy ranged from 25 to 69 percent, according to the ADA and CDC/EPA recommendations, compared with the R2A agar. Conclusions. Overall, the in-office test kits underestimated bacteria levels, producing inaccurate measurements of bacterial levels compared with the R2A agar. Clinical Implications. The data suggest that use of the two in-office test kits could result in a lack of compliance, owing to underestimating bacterial contamination with recognized recommendations for dental unit waterline quality.

Original languageEnglish (US)
Pages (from-to)363-371
Number of pages9
JournalJournal of the American Dental Association
Issue number3
StatePublished - Mar 2006
Externally publishedYes


  • Biofilms
  • Dental infection control
  • Dental unit waterlines
  • Water microbiology
  • Water quality

ASJC Scopus subject areas

  • Dentistry(all)


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