Cleansing technique using high-velocity steam-air micromist jet spray

A Personalised 3D-Printed Dental Plaque Removal Mouthguard for Older Adults

OBJECTIVES

The aim of the present study was to examine the plaque removal effectiveness of a personalised 3D-printed dental plaque removal mouthguard device in a clinical trial setting.

METHODS

A personalised 3D-printed mouthguard was developed to clean dental plaque using micro-mist. A clinical trial was conducted to examine the plaque removal effectiveness of this device. The clinical trial recruited 55 participants (21 males and 34 females) with an average age of 68.4 years (range, 60-81 years). Dental plaque was dyed by plaque disclosing liquid (Ci). Turesky Modification of the Quigley-Hein Plaque Index (TMQHPI) was used to evaluate the level and rate of plaque formation on the tooth surface. The TMQHPI was recorded and intraoral photos were taken before and after mouthguard cleaning. The plaque removal rate was calculated based on TMQHPI and intraoral photos (pixel-based method) before and after cleaning.

RESULTS

The personalised 3D-printed micro-mist injection mouthguard can be effective in dental plaque removal on tooth and gingiva, and the effectiveness lies between that of a manual toothbrush and a mouth rinse. The newly proposed pixel-based method can be a practical, high sensitive tool to evaluate the level of plaque formation.

CONCLUSIONS

Under the conditions of the present study, we conclude that the personalised 3D-printed micro-mist injection mouthguard can be useful in reducing dental plaque and may be especially suitable for older adults and disabled people.

Skin Cleansing Technique with Disinfectant using Improved High-Velocity Steam-Air Micromist Jet Spray

Application of a high-velocity steam-air micromist jet spray (HVS-AMJS) with disinfectants for cleansing the skin is proposed. Low-pressure steam is mixed with compressed air in a nozzle and then sprayed onto a surface of skin or material located approximately 22 cm from the nozzle. The temperature on the sprayed surface was controlled between 40ºC and 45 ºC. The improved HVS-AMJS installed scattering prevention cover with tap water effectively removed normal bacterial flora (total viable count and coliform bacteria) from contaminated skin pieces and pig skin wounds. Furthermore, the cleansing efficacy increased by advanced-treating with bio-shell calcium oxide (BiSCaO), hypochlorous acid (HClO), sodium hypochlorite (NaClO), povidone iodine, or chlorhexidine gluconate. Especially, the improved HVS-AMJS combined with BiSCaO had higher bactericidal activity than when combined with other disinfectants. This study suggests that application of the HVS-AMJS with disinfectants, especially BiSCaO, may be useful for skin cleansing to prevent infection.

Safety of Concentrated Bioshell Calcium Oxide Water Application for Surface and Skin Disinfections against Pathogenic Microbes

Immediately post-production, commercially available bioshell calcium oxide (BiSCaO) water is colorless, transparent, and strongly alkaline (pH 12.8), and is known to possess deodorizing properties and broad microbicidal activity. However, BiSCaO Water may represent a serious safety risk to the living body, given the strong alkalinity. This study aimed to investigate the safety of BiSCaO Water for use as an antiseptic/disinfectant despite concerns regarding its high alkalinity. The change over time in pH of BiSCaO Water was measured during air contact (stirring BiSCaO Water in ambient air). When sprayed on metal, plastic, wood piece, paper, and skin surfaces, the pH of BiSCaO Water decreased rapidly, providing a white powder coating upon drying. Scanning electron microscopy images, energy dispersive X-ray elemental mapping, and X-ray diffractograms showed that the dried powder residues of BiSCaO Water were composed primarily of calcium carbonate. These results suggested that BiSCaO Water is a potent reagent that may overcome the obstacles of being strongly alkaline, making this material appropriate for use in disinfection against pathogenic microbes.

Bioshell Calcium Oxide-Containing Liquids as a Sanitizer for the Reduction of Histamine Production in Raw Japanese Pilchard, Japanese Horse Mackerel, and Chub Mackerel

Recently, there has been an increase in the number of food poisoning cases associated with histamine in food, mainly in relation to histamine in fish. Here, we investigated methods to decrease histamine levels in Japanese pilchard, Japanese horse mackerel, and chub Mackerel, stored at 10 °C using various concentrations of heated scallop bioshell calcium oxide (BiSCaO) suspension, dispersion (BiSCaO + Na₂HPO₄), colloidal dispersion (BiSCaO + NapolyPO₄), scallop shell powder (SSP) Ca(OH)₂ in pure water (PW) or saline, and BiSCaO water. BiSCaO in a high alkaline pH solution chemically decomposes histamine poorly, but the partial flocculation/precipitation of histamine was observed with 1 and 0.2 wt.% BiSCaO dispersion and BiSCaO colloidal dispersion, respectively. Cleaning fish samples with BiSCaO suspension, dispersion, colloidal dispersion, or BiSCaO water remarkably reduced histamine levels and normal bacterial flora (coliform bacteria (CF) and total viable bacterial cells (TC)) after storage for four days at 10 °C, while much higher histamine levels were observed after cleaning with saline. These results suggest that cleaning fish with BiSCaO dispersion, colloidal dispersion, or BiSCaO water can significantly reduce histamine levels through their bactericidal activity against histamine-producing bacteria.

Concentrated Bioshell Calcium Oxide (BiSCaO) Water Kills Pathogenic Microbes: Characterization and Activity

Bioshell calcium oxide (BiSCaO) exhibits deodorizing properties and broad microbicidal activity. In this study, we examined possible utility of BiSCaO Water for that purpose. BiSCaO Water was prepared by adding 10 wt% BiSCaO to clean water and gently collecting the supernatant in a bottle. The same volume of clean water was gently poured onto the BiSCaO precipitate and the supernatant was gently collected in a bottle; this process was repeated fifty times. The produced BiSCaO Water contained nanoparticles (about 400-800 nm) composed of smaller nanoparticles (100-200 nm), and was colorless and transparent, with a pH > 12.7. In vitro assays demonstrated that BiSCaO Water eliminated more than 99.9% of influenza A (H1N1) and Feline calicivirus, Escherichia coli such as NBRC 3972 and O-157:H7, Pseudomonas aeruginosa, Salmonella, and Staphylococcus aureus within 15 min. We compared BiSCaO Water with the other microbicidal reagents such as ethanol, BiSCaO, BiSCa(OH)₂ suspensions, povidone iodine, NaClO, BiSCaO dispersion and colloidal dispersion with respect to deodorization activity and microbicidal efficacy. The results showed that BiSCaO Water was a potent reagent with excellent deodorization and disinfection activities against pathogenic bacteria and viruses (including both enveloped and nonenveloped viruses).

Application of Colloidal Dispersions of Bioshell Calcium Oxide (BiSCaO) for Disinfection

Bioshell calcium oxide (BiSCaO) is a scallop-shell powder heated at a high temperature. BiSCaO is composed mainly of calcium oxide and exhibits broad microbicidal properties. The aim of this study is to evaluate the disinfection and decontamination abilities of BiSCaO colloidal dispersions with that of commercially available bioshell calcium hydroxide (BiSCa(OH)2) following the formation of flocculants/precipitates under strongly alkaline conditions (pH 11.5-12.2). Various concentrations of BiSCaO and BiSCa(OH)2 colloidal dispersions were prepared by mixing with Na-polyPO4 (PP) and Na-triPO4 (TP) as flocculating agents. The microbicidal activities, and the degree of flocculation/precipitation of trypan blue, albumin, chondroitin sulfate, heparin, non-anticoagulant heparin carrying polystyrene (NAC-HCPS), and low-molecular-weight heparin/protamine nanoparticles (LMWH/P NPs) were dependent on the pH, the average particle diameter, and the concentration of BiSCaO or BiSCa(OH)2 and of the phosphate compound. BiSCaO (average particle diameter: 6 μm) colloidal dispersions (0.2 wt.%) containing 0.15 wt.% PP or TP exhibited substantially stronger microbicidal activity and flocculation/precipitation under strongly alkaline conditions. These results suggest that BiSCaO colloidal dispersions together with phosphate compounds have practical applicability for disinfection.

Comparison of Various Disinfectants on Bactericidal Activity Under Organic Matter Contaminated Environments

The bactericidal activity of heated bio-shell calcium oxide (BiSCaO) powder suspension (pH 12.4) , hypochlorous acid (HClO; pH 6), sodium hypochlorite (NaClO; pH 8) , povidone-iodine (Isodine solution^®) , and chlorhexidine gluconate (Hibiscrub^®) under organic matter contaminated environments were compared for tests conducted on wood scraps and pig skin pieces that were incubated with normal bacterial flora (total viable counts and coliform bacteria) . The test results showed that BiSCaO suspension had higher bactericidal activity than HClO and NaClO. Furthermore, more than 10-fold higher concentrations of antiseptics such as povidone-iodine and chlorhexidine gluconate were required to achieve bactericidal activity comparable to that of BiSCaO suspension. Our results demonstrate the possibility of using BiSCaO suspension under organic matter contaminated environments as a disinfectant for environmental and food hygiene applications.

Preparation and Application of Bioshell Calcium Oxide (BiSCaO) Nanoparticle-Dispersions with Bactericidal Activity

Scallop-shell powder (SSP) heated at high temperature exhibits high pH and broad antimicrobial activity. Bioshell calcium oxide (BiSCaO) is an SSP composed mainly of calcium oxide. It is poorly water-soluble under alkaline conditions and the generated precipitate can plug spray nozzles. The aim of this study was to establish that BiSCaO dispersion caused no significant CaO loss and plugging of spray nozzles, and to evaluate its deodorization and microbicidal abilities and its ability to reduce the concentrations of NO₂^- and NO₃^-. BiSCaO dispersions were prepared by mixing various concentrations of BiSCaO suspension, while phosphate compounds such as Na₃PO₄, Na₂HPO₄ or NaH₂PO₄ and the pH, average diameter, zeta potential, and form of the compounds with cryo-SEM were evaluated. We evaluated deodorization using tainted pork meat and microbicidal efficacy using contaminated suspension with normal bacterial flora. The concentration of NO₂^- and NO₃^- after mixing BiSCaO dispersion and pure water containing a high proportion of NO₂^- and NO₃^- were measured. BiSCaO dispersion formed with Na₂HPO₄, whose ratio to BiSCaO was 60%, showed a high pH (>12), a small particle diameter (>181 nm) and was stable for seven days. The BiSCaO dispersion showed higher deodorization and microbicidal activities than SSP-Ca(OH)₂, which was mainly composed of Ca(OH)₂. BiSCaO, but not SSP-Ca(OH)₂, could reduce the concentration of NO₂^- and NO₃^- by more than 90% within 15 min. We developed a stable BiSCaO dispersion, and it had high deodorization and microbicidal efficacy. These activities of BiSCaO might result from the high pH caused by CaO hydration and a reduction activity causing active radical species.