Table 1.
Microbial contamination of dental unit waterlines.
| Control | Intermittent Disinfection | Continuous Disinfection | |||
|---|---|---|---|---|---|
| Microbiological indicators | untreated | hydrogen peroxide, peracetic acid 0.26% | hydrogen peroxide, peracetic acid 0.26% | hydrogen peroxide, silver ions 0.02% | stabilized ClO2 0.22% |
| mains water n: 18 | mains water n: 18 | deionized water n: 18 | deionized water n: 18 | reverse osmosis n: 18 | |
| HPC 22 °C | |||||
| positive samples (%) | 100% | 100% | 100% | 22.2% | 55.6% |
| range (log10 CFU/mL) | (2.00–3.87) | (1.30–2.96) | (0.30–3.86) | (0.00–1.00) | (0.00–1.85) |
| mean ± SD (log10 CFU/mL) | 3.11 ± 0.47 | 1.95 ± 0.60 | 2.20 ± 1.18 | 0.14 ± 0.30 | 0.68 ± 0.73 |
| HPC 36 °C | |||||
| positive samples (%) | 100% | 100% | 94.14% | 27.8% | 100% |
| range (log10 CFU/mL) | (3.00–4.00) | (0.56–2.96) | (0.00–3.57) | (0.00–1.04) | (0.30–2.20) |
| mean ± SD (log10 CFU/mL) | 3.41 ± 0.37 | 2.26 ± 0.43 | 2.30 ± 1.01 | 0.19 ± 0.36 | 1.06 ± 0.60 |
| Pseudomonas aeruginosa | |||||
| positive samples (%) | 27.8% | 55.6% | 27.8% | absent in all samples | absent in all samples |
| range (log10 CFU/100 mL) | (0.00–1.49) | (0.00–1.41) | (0.00–3.00) | ||
| mean ± SD (log10 CFU/100 mL) | 0.17 ± 0.38 | 0.55 ± 0.60 | 0.61 ± 1.05 | ||