Evaluation of Antimicrobial-Antibiofilm Activity of a Hydrogen Peroxide Decontaminating System Used in Dental Unit Water Lines

Germano Orrù1, *, Susanna Del Nero2, Enrica Tuveri1, Maria Laura Ciusa1, Francesca Pilia1, Matteo Erriu1, Ginevra Orrù3, Manuele Liciardi3, Vincenzo Piras1, Gloria Denotti1
1 OBL (Oral Biotechnology Laboratory), Dipartimento di Chirurgia e Scienze Odontostomatologiche, Universita' degli Studi di Cagliari, Cagliari, Italy
2 CEFLA Dentale, Imola, Italy
3 Istituto Zooprofilattico Sperimentale della Sardegna, Cagliari, Italy

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© Orrù et al.; Licensee Bentham Open.

open-access license: This is an open access article licensed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted, non-commercial use, distribution and reproduction in any medium, provided the work is properly cited.

* Address correspondence to this author at the Dipartimento di Chirurgia e Scienze Odontostomatologiche, Università degli Studi di Cagliari, Via Binaghi 4, 09121 Cagliari-Italy; Tel: +39 070537413; Fax: +39 070 537437; E-mail:


A dental unit water line (DUWL) equipped with a device designed to automatically and continually flush a bacteriostatic solution of hydrogen peroxide (WHE) and a discontinuous disinfecting system (BIOSTER) was evaluated. In the first instance a preliminary sensitivity test on a large number of microorganisms (bacteria and fungi) was tried with a H2O2 range from 100 to 800 ppm. The bacteria frequently reported in DUWL (including Pseudomonas spp, Streptococcus spp., Staphylococcus spp., E. coli) and some periodontal pathogens showed a minimum inhibitory concentration from 100 to 300 H2O2 ppm (also including M. marinum and C. albicans). However, H2O2 did not show any inhibitory effects against: A. actinomycetemcomitans, C. glabrata C. parapsilos, F. nucleatum, M. micros. In a second step, the DUWL was experimentally infected with S. faecalis, E. coli, P. aeruginosa, S. aureus. After disinfection steps with 3% H2O2, the inhibitory effect on planktonic forms and on sessile biofilm was measured. In a third step, the count of 16S rRNA gene copies by real time PCR at different points of the DUWL described an accrue of bacterial slime in “hot spot” regions characterized by irregular/slow water flux (valves, elbows). However these results suggest that hydrogen peroxide is not only able to inhibit bursts of planktonic bacteria inside the DUWL, but that it could also be effective against sessile biofilm containing heterotrophic microorganisms derived from domestic water line contamination. In addition some oral pathogens could be contaminating and surviving in DUWL.

Keywords: Dental Unit Water Lines, Hydrogen Peroxide, Biofilm.