Assessment of Inhibitory Effects of Fluoride-Coated Tubes on Biofilm Formation by Using the In Vitro Dental Unit Waterline Biofilm Model

Abstract

This study aimed to establish an in vitro model to simulate biofilms formed in dental unit waterlines (DUWLs) and to investigate the ability of polyvinylidene fluoride (PVDF)-coated tubes to inhibit biofilm formation using this model. The water and biofilm samples were obtained from DUWLs which had been clinically used for 2.5 years, and the predominant bacteria were identified. A conventional polyurethane tube was incubated for 24 to 96 h in the mixed flora of isolated bacteria, and the optimal incubation conditions to simulate a clinically formed biofilm were determined by observation with a scanning electron microscope. Biofilm formation on a PVDF-coated tube was observed using this in vitro model, and the adherence of different bacterial species to conventional and PVDF-coated tubes was assessed. Sphingomonas paucimobilis, Acinetobacter haemolytics, and Methylobacterium mesophilicum were predominantly isolated from contaminated DUWLs. Incubation of the polyurethane tube with the mixed flora containing these three species for 96 h resulted in the formation of a mature biofilm similar to the one clinically observed. The PVDF-coated tube was significantly less adhesive to all three bacterial species than the polyurethane tube (P < 0.05 by the MannWhitney U test), and the attachment of small amounts of rods was observed even after incubation with the mixed flora for 96 h. In conclusion, an in vitro biofilm model was obtained by using a mixed flora of bacteria isolated from DUWLs, and the PVDF-coated tube was found to be effective in preventing biofilm formation using this model.

An Assessment of the Bacterial Diversity found in Dental Unit Waterlines using the Illumina MiSeq

“…In our study, we found that Acinetobacter spp. made up less than 1% of the bacteria identified, counter to observations by Yabune et al (2008) and Barbeau et al (1996) that found a high proportion were this genus. Although bacterial diversity is likely to be different depending on the study, identification of Sphingomonas and Methylobacterium are common to each study and likely represent the core bacterial genera found in water from DUWLs.…”

“…Previous studies performed in Canada using culturing techniques have confirmed that there can be significant contamination in water from DUWLs, and Sphingomonas paucimobilis, Acinetobacter calcoaceticus, Methylobacterium mesophilicum, and Pseudomonas aeruginosa were the predominant bacterial species (Barbeau et al, 1996) . Yabune et al (2008) have also shown that the dominant bacteria in water from DUWLs located in a Japanese dental hospital were also Sphingomonas paucimobilis, Acinetobacter haemolytics, and Methylobacterium mesophilicum. A more recent study using high-throughput DNA sequencing techniques has more comprehensively characterized the bacterial diversity of water from DUWLs in France (Costa et al, 2015) , showing frequent contamination by Sphingomonas and Halomonas.…”

“…As DUWL water is used in most dental treatments, it may be a potential source of infection for both staff and patients. Many studies have examined the bacterial contamination present in DUWLs but few have examined the types of microorganisms in detail (Barbeau et al, 1996;Costa et al, 2015;Szymanska and Sitkowska, 2013a;Walker et al, 2004;Yabune et al, 2008) . In addition, most of these studies have assessed the bacterial diversity of water from DUWLs using in vitro cultivation (Barbeau et al, 1996;Szymanska and Sitkowska, 2013a;Yabune et al, 2008) .…”

Synthesis of eucalyptus/tea tree oil absorbed biphasic calcium phosphate–PVDF polymer nanocomposite films: a surface active antimicrobial system for biomedical application

“…In the present case, the main component of EU is 1,8-cineole and that of TTO is terpinene-4-ol but as already mentioned before, a host of other components namely citronellal, citronellol, citronellyl acetate, p-cymene, eucamalol, limonene, linalool, g-terpinene, a-terpinol, a-terpinene, terpinolene, r-cymene, and a-pinene are also present in varying amounts. 59 Thus in the case of EU and TTO films, the results obtained may indicate the cumulative effect of two factors: (a) bacterial adsorption on PVDF films promoted by OCP and HAp phase and (b) inhibitory effect of the essential oil coated film which serves to reinforce the antibacterial efficacy of the nanocomposite films. 17,19,[22][23][24] Since bacterial cells have a tendency to form biofilms on inorganic substrates, FESEM studies of the EU and TTO surfaces were also done to evaluate film-bacteria interfacial interactions (Fig.…”

Opportunistic Bacteria in Dental Unit Waterlines: Assessment and Characteristics

“…They also stress that it is necessary to develop and use effective methods of reducing DUWL microbiological load [8,38,39].…”