Effectiveness and safety of low-concentrated ozonized water for the reduction of contamination in dental unit water lines

Contamination of dental unit waterlines (DUWL) with heterotrophic bacteria can cause problems in immune compromised patients (aged, tumor and organ transplantation-patients). We focused on the use of low-concentrated ozonized water (OZW) as the biofilm formation restraint system for DUWL. Here, we examined the effects of low-concentrated OZW on the growth of bacteria and related biofilm formation and harmfulness to dental unit components (DUCs) in vitro. Objectives To evaluate the bactericidal effects of OZW on biofilms in DUWL and DUC in vitro. Methods Low-concentrated OZW (0.4 mg/L) was generated using an OZS-PTDX generator. Heterotrophic bacterial biofilms in old DUWL tubes and Candia albicans solution (control microbe) were treated with OZW for 1 h with gentle agitation before static culturing for 96 h in Reasoner's 2A liquid media. The control solutions were 0.1% cetylpyridinium chloride (CPC), chlorinated tap water (TW), and phosphate-buffered saline (PBS). Adenosine triphosphate (ATP) amounts of the microbes were measured and the biofilms of these microbes were observed using scanning electron microscopy (SEM). Moreover, surfaces of DUC soaked in OZW and TW were observed by SEM. Results The OZW reduced ATP levels in microbes to 50% compared to TW and PBS treatment, although CPC reduced it below detection limits. SEM observation revealed deformation of microbes cultured with OZW, whereas no changes were seen on DUC surfaces. Conclusions Low-concentrated OZW is bactericidal against heterotrophic bacteria biofilms and it is not harmful to DUC, suggesting that it might be useful in preventing DUWL contamination

Evaluation of the simulator with automatic irrigation control system designed for countermeasures of internal contamination in dental unit water lines

The prevention of nosocomial infections is an imperative task. The dental chair unit (DCU) is an indispensable device used in dental treatment. However, it is known that the dental unit water line (DUWL) can become contaminated with biofilm, consisting mainly of heterotrophic bacteria (HB). Recently, the International Organization for Standardization specified the methods for testing DUWL contamination management. On these grounds, a simulator reproducing DUWL was prepared to standardize the examination method of the DUWL contamination. Objectives To evaluate the reproducibility of the DUWL simulator, monitor the DUWL contamination states, and test the efficacy of a commercial decontaminant for DUWL. Methods The DUWL simulator was assembled by a DCU manufacturing company. The simulator's DUWL was filled with tap water (TW), and left for approximately one year. Neutral electrolyzed water (NEW) was used as a decontaminant for DUWL. Both TW and NEW were passed through DUWL in a timely manner simulating daily dental treatment. Water was sampled from the air turbine hand piece weekly for 4 weeks and used for HB culture. Contamination status was evaluated by measuring bacterial adenosine triphosphate release and by culturing on Reasoner's 2A medium. Results The DUWL released contaminated water had a bacterial count of over 6 × 104 cfu/mL. After passing NEW through DUWL for 1 week, the count drastically decreased to its basal level and remained steady for 4 weeks. However, TW showed no effect on DUWL decontamination throughout the examination periods. Conclusions The DUWL simulator could be useful to examine the efficacy of the decontaminant for DUWL and development of new methods in DUWL contamination management

Effect of CYP2C19 Polymorphism on Treatment Success in Lansoprazole-Based 7-Day Treatment Regimen for Cure of H. pylori Infection in Japan

Recently, Helicobacter pylori (H. pylori)-positive peptic ulcer patients were treated by a 1-week triple therapy [lansoprazole (LPZ) 30 mg, amoxicillin 750 mg and clarithromycin 200 or 400 mg, each twice daily] without the checking CYP2C19 genotype in Japan. This regimen was done to obtain sufficient cure rates for H. pylori infection using a high dose of LPZ (60 mg/day) without the great cost of having to determine the genotype. However, the failure rate for eradicating H. pylori was reported to be 12.5%. The reasons for this were studied in 33 Japanese patients with H. pylori-positive gastric or duodenal ulcer. Blood samples of the patients were collected to determine the genotype of CYP2C19 and plasma concentrations of LPZ and its metabolites at 3 h postdose on the morning of the 7th day of treatment. H. pylori infection was cured in 25 of the 33 patients (75.8%). The cure rate was highest in the group of poor metabolizers (PM), intermediate in the group of extensive metabolizers of the heterozygous type (htEM) and lowest in the group of extensive metabolizers of the homozygous type (hmEM). The relative ratio of mean plasma concentration for LPZ among the 3 groups was 1.00:1.43:2.93 (hmEM:htEM:PM groups). Our data suggest that success of the eradication is dependent on the CYP2C19-related genotypic status or the plasma concentrations of LPZ in a steady state condition after a multiple dosing regimen; that is to say, checking CYP2C19 is necessary even on occasions when treatment is done by H. pylori eradication methods as performed in Japan