Skip to main content
NCBI home page
Applied and Environmental Microbiology logoLink to Applied and Environmental Microbiology
. 1996 Nov;62(11):3954–3959. doi: 10.1128/aem.62.11.3954-3959.1996

Multiparametric analysis of waterline contamination in dental units.

J Barbeau 1, R Tanguay 1, E Faucher 1, C Avezard 1, L Trudel 1, L Côté 1, A P Prévost 1
PMCID: PMC168213  PMID: 8899982

Abstract

Microbial contamination of dental unit waterlines is thought to be the result of biofilm formation within the small-bore tubing used for these conduits. Systematic sampling of 121 dental units located at the dental school of Université de Montréal showed that none of the waterlines was spared from bacterial contamination. Multilevel statistical analyses showed significant differences between samples taken at the beginning of the day and samples taken after a 2-min purge. Differences were also found between water from the turbine and the air/water syringe. Random variation occurred mainly between measurements (80%) and to a lesser extent between dental units (20%). In other analyses, it was observed to take less than 5 days before initial bacterial counts reached a plateau of 2 x 10(5) CFU/ml in newly installed waterlines. Sphyngomonas paucimobilis, Acinetobacter calcoaceticus, Methylobacterium mesophilicum, and Pseudomonas aeruginosa were the predominant isolates. P. aeruginosa showed a nonrandom distribution in dental unit waterlines, since 89.5% of the all the isolates were located in only three of the nine clinics tested. Dental units contaminated by P. aeruginosa showed significantly higher total bacterial counts than the others. By comparison, P. aeruginosa was never isolated in tap water remote from or near the contaminated dental unit waterlines. In conclusion, dental unit waterlines should be considered an aquatic ecosystem in which opportunistic pathogens successfully colonize synthetic surfaces, increasing the concentration of the pathogens in water to potentially dangerous levels. The clinical significance of these findings in relation to routine dental procedures is discussed.

Full Text

The Full Text of this article is available as a PDF (417.7 KB).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Abel L. C., Miller R. L., Micik R. E., Ryge G. Studies on dental aerobiology. IV. Bacterial contamination of water delivered by dental units. J Dent Res. 1971 Nov-Dec;50(6):1567–1569. doi: 10.1177/00220345710500063601. [DOI] [PubMed] [Google Scholar]
  2. Anaissie E., Samonis G., Kontoyiannis D., Costerton J., Sabharwal U., Bodey G., Raad I. Role of catheter colonization and infrequent hematogenous seeding in catheter-related infections. Eur J Clin Microbiol Infect Dis. 1995 Feb;14(2):134–137. doi: 10.1007/BF02111873. [DOI] [PubMed] [Google Scholar]
  3. Beierle J. W. Dental operatory water lines. J Calif Dent Assoc. 1993 Feb;21(2):13–15. [PubMed] [Google Scholar]
  4. Botzenhart K., Puhr O. F., Döring G. Pseudomonas aeruginosa in der Mundhöhle: Häufigkeit und Altersverteilung von Keimträgern bei Erwachsenen. Zentralbl Bakteriol Mikrobiol Hyg B. 1985 May;180(5-6):471–479. [PubMed] [Google Scholar]
  5. Campbell M. E., Farmer S. W., Speert D. P. New selective medium for Pseudomonas aeruginosa with phenanthroline and 9-chloro-9-[4-(diethylamino)phenyl]-9,10-dihydro-10- phenylacridine hydrochloride (C-390). J Clin Microbiol. 1988 Sep;26(9):1910–1912. doi: 10.1128/jcm.26.9.1910-1912.1988. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Costerton J. W., Cheng K. J., Geesey G. G., Ladd T. I., Nickel J. C., Dasgupta M., Marrie T. J. Bacterial biofilms in nature and disease. Annu Rev Microbiol. 1987;41:435–464. doi: 10.1146/annurev.mi.41.100187.002251. [DOI] [PubMed] [Google Scholar]
  7. Dewar J. W., Wagner K. R. Peritonitis due to Methylobacterium mesophilicum complicating ambulatory peritoneal dialysis--British Columbia. Can Dis Wkly Rep. 1988 Dec 3;14(48):217–219. [PubMed] [Google Scholar]
  8. Douglas C. W., Rothwell P. S. Evaluation of a dental unit with a built-in decontamination system. Quintessence Int. 1991 Sep;22(9):721–726. [PubMed] [Google Scholar]
  9. Fiehn N. E., Henriksen K. Methods of disinfection of the water system of dental units by water chlorination. J Dent Res. 1988 Dec;67(12):1499–1504. doi: 10.1177/00220345880670121101. [DOI] [PubMed] [Google Scholar]
  10. Fitzgibbon E. J., Bartzokas C. A., Martin M. V., Gibson M. F., Graham R. The source, frequency and extent of bacterial contamination of dental unit water systems. Br Dent J. 1984 Aug 11;157(3):98–101. doi: 10.1038/sj.bdj.4805436. [DOI] [PubMed] [Google Scholar]
  11. Furuhashi M., Miyamae T. Prevention of bacterial contamination of water in dental units. J Hosp Infect. 1985 Mar;6(1):81–88. doi: 10.1016/s0195-6701(85)80022-0. [DOI] [PubMed] [Google Scholar]
  12. Gervich D. H., Grout C. S. An outbreak of nosocomial Acinetobacter infections from humidifiers. Am J Infect Control. 1985 Oct;13(5):210–215. doi: 10.1016/0196-6553(85)90059-8. [DOI] [PubMed] [Google Scholar]
  13. Govan J. R. In vivo significance of bacteriocins and bacteriocin receptors. Scand J Infect Dis Suppl. 1986;49:31–37. [PubMed] [Google Scholar]
  14. Govan J. R. Mucoid strains of Pseudomonas aeruginosa: the influence of culture medium on the stability of mucus production. J Med Microbiol. 1975 Nov;8(4):513–522. doi: 10.1099/00222615-8-4-513. [DOI] [PubMed] [Google Scholar]
  15. Gross A., Devine M. J., Cutright D. E. Microbial contamination of dental units and ultrasonic scalers. J Periodontol. 1976 Nov;47(11):670–673. doi: 10.1902/jop.1976.47.11.670. [DOI] [PubMed] [Google Scholar]
  16. Hobbie J. E., Daley R. J., Jasper S. Use of nuclepore filters for counting bacteria by fluorescence microscopy. Appl Environ Microbiol. 1977 May;33(5):1225–1228. doi: 10.1128/aem.33.5.1225-1228.1977. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Kelstrup J., Funder-Nielsen T. D., Theilade J. Microbial aggregate contamination of water lines in dental equipment and its control. Acta Pathol Microbiol Scand B. 1977 Jun;85(3):177–183. doi: 10.1111/j.1699-0463.1977.tb01693.x. [DOI] [PubMed] [Google Scholar]
  18. Kerr J. Inhibition of fungal growth by Pseudomonas aeruginosa and Pseudomonas cepacia isolated from patients with cystic fibrosis. J Infect. 1994 May;28(3):305–310. doi: 10.1016/s0163-4453(94)91943-7. [DOI] [PubMed] [Google Scholar]
  19. Korvick J. A., Rihs J. D., Gilardi G. L., Yu V. L. A pink-pigmented, oxidative, nonmotile bacterium as a cause of opportunistic infections. Arch Intern Med. 1989 Jun;149(6):1449–1451. [PubMed] [Google Scholar]
  20. LeChevallier M. W., Seidler R. J., Evans T. M. Enumeration and characterization of standard plate count bacteria in chlorinated and raw water supplies. Appl Environ Microbiol. 1980 Nov;40(5):922–930. doi: 10.1128/aem.40.5.922-930.1980. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Lewis D. L., Arens M., Appleton S. S., Nakashima K., Ryu J., Boe R. K., Patrick J. B., Watanabe D. T., Suzuki M. Cross-contamination potential with dental equipment. Lancet. 1992 Nov 21;340(8830):1252–1254. doi: 10.1016/0140-6736(92)92950-k. [DOI] [PubMed] [Google Scholar]
  22. Martin M. V. The significance of the bacterial contamination of dental unit water systems. Br Dent J. 1987 Sep 5;163(5):152–154. doi: 10.1038/sj.bdj.4806220. [DOI] [PubMed] [Google Scholar]
  23. McEntegart M. G., Clark A. Colonisation of dental units by water bacteria. Br Dent J. 1973 Feb 20;134(4):140–142. doi: 10.1038/sj.bdj.4802969. [DOI] [PubMed] [Google Scholar]
  24. Mills S. E., Lauderdale P. W., Mayhew R. B. Reduction of microbial contamination in dental units with povidone-iodine 10%. J Am Dent Assoc. 1986 Aug;113(2):280–284. doi: 10.14219/jada.archive.1986.0178. [DOI] [PubMed] [Google Scholar]
  25. Morrison A. J., Jr, Shulman J. A. Community-acquired bloodstream infection caused by Pseudomonas paucimobilis: case report and review of the literature. J Clin Microbiol. 1986 Nov;24(5):853–855. doi: 10.1128/jcm.24.5.853-855.1986. [DOI] [PMC free article] [PubMed] [Google Scholar]
  26. Oppenheim B. A., Sefton A. M., Gill O. N., Tyler J. E., O'Mahony M. C., Richards J. M., Dennis P. J., Harrison T. G. Widespread Legionella pneumophila contamination of dental stations in a dental school without apparent human infection. Epidemiol Infect. 1987 Aug;99(1):159–166. doi: 10.1017/s095026880006698x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  27. Pankhurst C. L., Philpott-Howard J. N. The microbiological quality of water in dental chair units. J Hosp Infect. 1993 Mar;23(3):167–174. doi: 10.1016/0195-6701(93)90022-r. [DOI] [PubMed] [Google Scholar]
  28. Reasoner D. J., Blannon J. C., Geldreich E. E., Barnick J. Nonphotosynthetic pigmented bacteria in a potable water treatment and distribution system. Appl Environ Microbiol. 1989 Apr;55(4):912–921. doi: 10.1128/aem.55.4.912-921.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
  29. Reasoner D. J., Geldreich E. E. A new medium for the enumeration and subculture of bacteria from potable water. Appl Environ Microbiol. 1985 Jan;49(1):1–7. doi: 10.1128/aem.49.1.1-7.1985. [DOI] [PMC free article] [PubMed] [Google Scholar]
  30. Reinthaler F. F., Mascher F., Stünzner D. Serological examinations for antibodies against Legionella species in dental personnel. J Dent Res. 1988 Jun;67(6):942–943. doi: 10.1177/00220345880670061001. [DOI] [PubMed] [Google Scholar]
  31. Slots J., Feik D., Rams T. E. Prevalence and antimicrobial susceptibility of Enterobacteriaceae, Pseudomonadaceae and Acinetobacter in human periodontitis. Oral Microbiol Immunol. 1990 Jun;5(3):149–154. doi: 10.1111/j.1399-302x.1990.tb00413.x. [DOI] [PubMed] [Google Scholar]
  32. Whitehouse R. L., Peters E., Lizotte J., Lilge C. Influence of biofilms on microbial contamination in dental unit water. J Dent. 1991 Oct;19(5):290–295. doi: 10.1016/0300-5712(91)90075-a. [DOI] [PubMed] [Google Scholar]
  33. Williams H. N., Quinby H., Romberg E. Evaluation and use of a low nutrient medium and reduced incubation temperature to study bacterial contamination in the water supply of dental units. Can J Microbiol. 1994 Feb;40(2):127–131. doi: 10.1139/m94-020. [DOI] [PubMed] [Google Scholar]
  34. Zobell C. E. The Effect of Solid Surfaces upon Bacterial Activity. J Bacteriol. 1943 Jul;46(1):39–56. doi: 10.1128/jb.46.1.39-56.1943. [DOI] [PMC free article] [PubMed] [Google Scholar]
  35. Zottola E. A., Sasahara K. C. Microbial biofilms in the food processing industry--should they be a concern? Int J Food Microbiol. 1994 Oct;23(2):125–148. doi: 10.1016/0168-1605(94)90047-7. [DOI] [PubMed] [Google Scholar]
  36. von Graevenitz A. The role of opportunistic bacteria in human disease. Annu Rev Microbiol. 1977;31:447–471. doi: 10.1146/annurev.mi.31.100177.002311. [DOI] [PubMed] [Google Scholar]

Articles from Applied and Environmental Microbiology are provided here courtesy of American Society for Microbiology (ASM)

RESOURCES