Table 5 Electrolyzed water use in the dental office

1

Nakano M., et al. 2020 [translated from Japanese] [63]

Tsurumi University, Japan

CCT

To evaluate the efficacy of slightly acidic electrolyzed water.

(SAEW) against the contamination of the water line of dental units

High-speed handpiece (HS-1), an ultrasonic scaler, and a cup filler of the prototype dental unit.

Slightly acidic electrolyzed water: pH 5.0–6.5

SAEW generator (PureStar, Morinaga Milk Industry). The liquid was treated in a non-diaphragmatic electrolyzer with an effective chlorine concentration of 10–80 ppm, hypochlorous acid solution.

Tap water in the same dental unit

CFU/mL of Heterotrophic bacteria

SAEW showed a significantly smaller number of heterotrophic bacteria than tap water.

SAEW continuously used for 7 years was effective for contamination control in the water line of dental units.

2

Ichioka Y., et al. 2020 [28]

Health Sciences University of Hokkaido, Japan

In vitro

To determine cytocompatibility of experimentally contaminated titanium surfaces, using a S. gordonii biofilm after chemical treatment with AEW or diluted H2O2 following air-abrasive debridement.

S. gordonii cultivated on Titanium specimens.

Alkaline electrolyzed water (AEW): chlorine concentration of 0.05%, pH 9.0

EPIOS Care® (EPIOS Corp., Tokyo, Japan).

H2O2 and NaCl

CFU/mL

The bactericidal effects of AEW and H₂O₂ treatments were significantly higher than that of NaCl treatment. There was no significant difference in bactericidal effect between AEW and H₂O₂ treatments.

AEW does not possess marked cytotoxicity and showed superior capacity in restoring titanium surface chemical properties compared with H₂O₂.

3

Okanda T., et al. 2019 [30]

Tokyo Medical University Hospital in Japan

In vitro

To determine the effectiveness of SAEW against biofilm-forming P. aeruginosa on medical devices

Seven strains of mucoid-type P. aeruginosa (PaM) and a non mucoid type of P.aeruginosa (PAO1)

Slightly acidic electrolyzed: (5,10,15,20 y 30 ppm) at 15 °C, 35 °C, and 45 °C. pH 5–6.5.

SAEW generator (Purester m-Clean; Morinaga Milk Industry Co., Tokyo, Japan) to a tap water source.

Distilled water

Presence or absence of growth of mucoid-type PaM. OD: absorbance of 580 nm.

PA cells treated with 15 ppm SAEW exhibited a partially destroyed cell wall and membrane structure and decreased cytoplasm density. Disruption of the cell structure was observed in most PA cells.

SAEW is an effective disinfectant for biofilm-forming P. aeruginosa and is a useful tool for disinfecting medical devices contaminated with biofilms.

4

Jeyapalan V., et al. 2018 [68]

Ragas Dental College and Hospital, Chennai, India

RCT

To comparatively evaluate the antimicrobial efficacy of three chemical disinfectants: 2.4% Glutaraldehyde (GA), 1% sodium hypochlorite (SH), and freshly prepared electrolyzed oxidizing water (EOW) on clinically derived PVS impressions

Four PVS impressions were made of the maxilla for each of the 10 subjects randomly on four different days.

EOW: 50 mg/L free chlorine, with pH of 2.5, and ORP of 1150 mv

EOW was obtained from an industrial source (Tianno Ti Anode Fabricators Pvt. Ltd., Chennai, India) using an electrolysis unit in their process with customized specifications.

2.4% GA, 1% SH, water

CFU/mL log10 count values and kill rate.

N^o CFU were observed in the group disinfected with EOW. EOW showed the highest log10 reduction value, which was statistically significant from both GA and SH, signifying higher an antimicrobial efficacy than the other two agents. EOW had 100% kill rate.

Freshly prepared EOW showed the highest mean log10 reduction values and 100% kill rate, indicating highest antimicrobial efficacy followed, being a promising option for disinfection of PVS impressions.

5

Fujita M., et al. 2017 [64]

Health Sciences University of Hokkaido, Japan

In vitro

To investigate the microbicidal effects of the electrolyzed water on microorganisms from DUWLs and assess any cytotoxic effects on cell lines derived from the human oral cavity

Water samples collected from Two dental units DUWLs: the air/water syringe, the high speed dental handpiece, and the cup filler

Electrolyzed water pH 7.2 ± 0.1 and ORP 793.7 n ± 9.3 mV, 21 ± 1 ppm Chlorine

Poseidon-S System (Self Medical Co., Kyoto, Japan)

Water from Dental unit reconnected to the municipal water system without a Poseidon-S

Number of CFU/mL of Gram-positive bacteria: S.mutans, S. sanguinis, E. faecalis, A. naeslundii, M. timidum, L.casei, P. acnes. Gram-negative Bacteria: V. parvula, P. gingivalis, P. intermedia, F. nucleatum.

After 18 hours of exposure to p-water, microorganisms from dental units failed to form colonies on R2A agar plates. P-water was found to reduce the viability of typical oral microbial cells from 10⁸ to 10⁶ CFU/mL, and it exhibited similar microbicidal activity against Gram-positive and Gram-negative species. This reduction represents a microbicidal rate of > 98.1%.

Poseidon-S system is an effective, additive-free disinfection system that reduces the microbial contamination of DUWLs and provides high quality water that is clean and safe for both patients and the environment.

6

Jnanadev KR., et al. 2011 [33]

V.S. Dental College, V.V. Puram, Bangalore, Karnataka, India

In vitro

To evaluate the disinfection capability of EAW as compared with 2% glutaraldehyde in disinfecting the heat cured acrylic resin prosthesis

30 acrylic specimens

Electrolyzed acid water (EAW): pH 2.3–2.4, ORP 1010–1030 mV

Two copper electrodes were placed in two beakers respectively and were connected to the positive and negative ends of a 4.5 A and6 V battery (electrolyzing apparatus). 50 mg of A grade sodium chloride (NaCl) in every 100 ml of distilled water was mixed to form 0.05% sodium chloride aqueous solution.

2% glutaraldehyde and without treatment

CFU/mL of S. aureus.

At 5 min, the desinfection potential didn’t show difference between EAW and 2% glutaraldehyde

The efficacy of EAW in eliminating the bacterial colonies on heat cured acrylic specimens raised from 99.88 to 99.995% as the immersion time was raised from 1 to 3 min, and complete disinfection was achieved at 5 min immersion time. As a disinfectant, EAW is as efficient as commercially available 2% glutaraldehyde at 5 min immersion time

7

Wu G., et al. 2008 [69]

Zhejiang University, Zhejiang, Republic of China

In vitro

To evaluate the feasibility of using ultrasonically nebulised electrolysed oxidising water (UNEOW) for disinfecting impressions, dental metals and gypsum casts.

1 × 1 × 0.5 cm discs of irreversible hydrocolloid impression material, gypsum cast and pure titanium

UNEOW: pH of 2.5, an ORP of 1150 mV, 50 ppm chlorine for 15, 30 and 45 min.

EOW was freshly generated using an EOW generator (SUNTECH-1000, ZH-Suntech, Zhuhai, China) and nebulised (Multisonic Compact TM, Schill Company, Probstzella Germany).

1% sodium hypochlorite for 10 min, no treatment

Kill rate (%) and log10 reduction of Staphylococcus spp. and spores of Bacillus sp, S. aureus and B. subtilis var. niger spores.

Immersion in EOW for 10 min resulted in a 100% kill rate for S. aureus and B. subtilis var. niger spores on titanium, alginate impressions and gypsum casts.

UNEOW used for 30–45 min with three dental materials showed satisfactory disinfection efficacy without compromising dimensional accuracy and surface quality

8

Gulabivala K., et al. 2004 [22]

Seoul National University, Seoul, Korea

In vitro

To evaluate the antibacterial effect of electrolyzed tap water (Puriwater) on toothbrushes contaminated with the periodontopathogens

A. actinomycetemcomitans, F. nucleatum, P. gingivalis, P. intermedia, and T. denticola. Seven brushes saliva collected from a total of 16 participants whom washed their mouths for 30 sec with Puri-water.

Electrolyzed water (Puri-water), pH 8.4.(exposure to EW 2 min, for 7 days).

Tap water of drinking water quality (pH 7.3, 0.76 ppm chlorine) was subjected to electrolysis (30 V of DC/300 mA) for 2 min at ambient temperature using an electrolysis apparatus equipped with platinum electrodes (280 × 120 × 90 mm, 650 g, SciacuaTM, Puri Co., Korea).

Tap water

CFU/mL or OD₆₆₀ of periodontopathogens, aerobes, anaerobes, and streptococci bacteria.

Bacteria on toothbrushes were significantly reduced by Puri-water. A. actinomycetemcomitans, F. nucleatum, P. intermedia, and P. gingivalis remaining in the Puri-water wash ranged between 11.0 and 12.4% of the amount remaining in the tap water wash. The growth of T. denticola was not observed in the Puri-water wash. The number of bacteria remaining on toothbrushes after washing with Puri-water was about 50% of that after washing with tap water. Aerobes and anaerobes in saliva were significantly reduced after washing with Puri-water compared to those after washing with tap water in the same subjects (p < 0.05). Significant reduction of mutans streptococci was also observed in all participants.

Electrolyzed tap water markedly inhibited the growth of salivary bacteria as well as cultured periodontopathogens. It can be made easily in a small scale and could be useful for daily oral hygiene if used as a mouthwash and for toothbrush washing.

9

Kohno S., et al. 2004 [65]

Hiroshima University, Hiroshima, Japan

CCT

To investigate the bacterial effects of the temporary inflow of acidic electrolyzed water (AEW) on microbial contamination of the DUWL.

6 dental units: hand pieces and three-way syringes.

Acid electrolyzed water, pH 2.7, ORP 1100 mV, 32 ppm chlorine.

AEW was produced by QueenH-AP from tap water (AQUA medical Hiroshima).

Water from 3 Units that didn’t receive AEW

CFU/mL of Legionella, Streptococcus, P. aeruginosa, E. coli, S. paucimobilis, M. mesophilicum, and P. stutzery

The mean viable bacteria count was 910 ± 190 CFU/mL at the handpiece, and 521 ± 116 CFU/mL at the three-way syringe before the inflow of AEW. On the next day after the inflow of acidic electrolyzed water, bacteria were detected in only negligible amounts on the hand-piece and three-way syringe, showing significant differences from the control chair.

Acidic electrolyzed water could be as an appropiate measure against bacterial contamination of the dental unit waterline.

10

Nagamatsu Y., et al. 2001 [71]

Kyushu Dental College, Japan

In vitro

To evaluate the sterilization effects of Electrolyzed Acid Water on a resin plate.

Resin plate: (30x30x3.0 mm) heat-curing acrylic resin (UR) and a self-curing acrylic resin (QR) with and without a tissue conditioning material (TC), inmmersed in solutions with or without adding ultrasound for 1,2,5,10 mins.

Electrolyzed Strong/weak Acid Water (SW/WW): pH SW: 2.3 ± 0.3, OPR: + 1170 ± 5 mV, 50 ± 25 ppm Chlorine WW: 5.7 ± 0.2, ORP + 873 ± 5 mV, 75 ± 25 ppm Chlorine

The strong acid water was prepared by electrolyzing 0.05% sodium chloride aqueous solution with an electrolyzing apparatus (SUPER WATER mini, Hirata Corp., Osaka, Japan). The weak acid water was prepared by electrolyzing tap water with an electrolyzing apparatus (ACIDENT, J. Morita Tokyo MFG. Corp., Tokyo, Japan).

Distilled water (DW)

Number of surviving bacteria/cm²: S. aureus

The immersion treatment in the electrolyzed acid water, SW and WW, showed a marked bactericidal effect. No surviving bacteria were found on all the resin plate specimens after 1-minute treatment. No more bacteria could be detected on UR with TC after 10-minute treatment regardless of the treating method and the type of acid water.

Both the electrolyzed strong and weak acid waters are well applicable as a disinfectant for acrylic denture base showing excellent bactericidal activities in a significantly shorter treatment as compared with the conventional denture cleaning.

11

Nagamatsu Y., et al. 2016 [70]

Kyushu Dental University, Kitakyushu, Japan

In vitro

To examine the bactericidal effect of neutral water for alginate impression comparing with those of electrolyzed waters

Three Impression (EX1, EX2 and EX3) taken with an alginate and EX4 the tray.

Strong acid water (SW) pH 2.4 (0.04), ORP + 1132 (5.7), 45 ppm chlorine. Slight acid water (WW) pH 6.5 (0.27), ORP + 877 (12.2), 51 ppm Chlorine, neutral water (NW) pH 7.0 (0.07), ORP + 849 (4.5) 38 ppm Chlorine

SW was prepared by electrolyzing 0.05% sodium chloride (first-grade, Wako Pure Chemical Industries, Osaka, Japan) aqueous solution with a diaphragm by an electrolyzing apparatus (SUPER WATER mini, Hirata, Osaka, Japan). WW was prepared by electrolyzing tap water containing a specified electrolyte without a diaphragm by an automatic apparatus (ACIDENT, J. Morita Tokyo MFG, Tokyo, Japan). NW was also automatically prepared using tap water containing 5% sodium chloride. It is obtained through two steps of electrolyzation using 5% sodium chloride aqueous solution, first without and second with a diaphragm (APaqua21, Asahipretec, Kobe, Japan).

Tap water (TW)

Number of bacteria of S. aureus

Only 1-min treatment in these electrolyzed waters, NW and the other two types, could disinfect all the surface of the alginate impression with the tray by addition of ultrasonic cle.aning. None of the bacteria could survive on the surface of the tray after only 1-min immersion in any electrolyzed water tested, NW and the other two types. No significant bactericidal effects were found among the three electrolyzed waters tested (p > 0.05)

The electrolyzed waters, above all the neutral water, may be the most appropriate for the disinfection of alginate impressions.

12

Walker JT., et al. 2003 [48]

Health Protection Agency, Porton Down, Salisbury SP4 0JG, United Kingdom

In vitro

To use a model to evaluate and compare the efficacy of a variety of products based on different classes of active compound on tubing surfaces

Biofilms model: Gram-negative and oxidase-negative, planktonic bacteria

Superoxidized water 2.5% Sterilox

Sterilox, Technologies, Abingdon, United Kingdom

Sterile water, Ozone, Combizyme, Tegodor, Sporklenz, Sodium hypochlorite, Chlorhexidine, Dialox, Betadine, Parmetol, Gigasept, Grotanol, Dioxiclear, Alpron, Sanosil, Oxigenal, Bio2000, Sterilex Ultra

TVC Log₁₀ CFU/cm² (%) and % Reduction of Viable count/ Biofilm coverage

Sterilox resulted in a 100%reduction in the biofilm TVC and a > 95% reduction of the biofilm coverage.

The study demonstrated that while many disinfectants achieve a sufficient reduction in TVC they may not necessarily remove unwanted biofilm from the tubing surfaces as tested in this laboratory-controlled biofilm model.

13

Campregher, U.B. 2011 [72]

Universidade federal do rio grande do sul, Brasil

In vitro

To develop a low-cost portable equipment for EW production and to evaluate the microbicidal effect of EW on acrilic resin contaminated with oral microorganisms

21 denture base acrylic resin(5x5x2)

Electrolyzed Acidic Water, pH 3.0 and oxidation reduction potential (ORP) of 1150 mV

EAW was produced through an electrolysis process of an aqueous NaCl solution (5%) in an electrolytic two chambers cell with a separation membrane between the chambers (30 V, 2 A).

Distilled water, Glutaraldehyde 2%

Turbidity %

Specimens treated with EAW didnt provoke turbidity on the culture media

EAW was effective in the disinfection of the acrylic resin contaminated by immersion of it for 10 minutes

14

Mishima S., et al. 2016 [66]

Kyoto University Hospital, Japan

RCT

To evaluate the effectiveness of inhibition of bacterial proliferation using the purification system to supply neutral electrolytic water for refining the waterworks in DUWLs.

Water samples were collected 6 dental units from the high-speed handpiece, the three-way syringe and the gargle water.

Neutral Electrolytic Water, pH of 6.5–7.5, 5 ppm chlorine

Poseidon S (Self Medical Co., Osaka, Japan) is purified electrolytic water from the tap water.

Tap water

CFU/mL pathogenic bacterial species

Before cleaning of DUWLs, the number of heterotrophic bacterium discharged from high-speed handpiece was 2.3 × 10⁵ cfu/mL, low-speed handpiece was 3.2 × 10⁴ cfu/mL, and threeway syringe was 1.3 × 10⁵ cfu/mL. After 3 and 14 months, the number of heterotrophic bacteria discharged from the high-speed handpieces, three-way syringes and gargle water was < 30 cfu/mL in EW treated group.

The water purification system using neutral electrolytic water was effective to control the proliferation of bacteria and could maintain a hygienic environment in DUWLs.

15

Martin, M., Gallagher, M. 2005 [67]

Liverpool Dental Hospital, UK

RCT

To determine the efficacy of super-oxidised water (Optident/Sterilox) in the decontamination of DUWLs.

Ten Adec Cascade units were used in the trial with independent reservoirs (The turbine, slow-speed, three-in-one syringe and cup-filler outlets).

Super–oxidised water

Optident/Sterilox,Optident (Ilkley, Yorkshire). On demand, the saline solution was passed through the generator producing concentrated super-oxidised water.

Not declared

Total CFU recover (range) of oral streptococci, Actinomyces spp, oral anaerobes, Enterobacteria, Pseudomonads, Candida, Legionella, and Mycobacterium spp.

The results show the number of CFU recovered from the first two weeks of the trial; after this period no further bacteria were recovered. After 7 d no further bacteria were recovered from the units.

Super-oxidised water was successful in the removal of bacteria from dental unit water supplies. Complete removal required the treatment with a purge phase of concentrated disinfectant and a maintenance phase of at least two weeks.