Physicochemical and pulp tissue dissolution properties of some household bleach brands compared with a dental sodium hypochlorite solution.

INTRODUCTION: Many clinicians use household bleach to irrigate root canals. Sodium hypochlorite solutions are also available from dental suppliers. We compared physicochemical features of these products and investigated their impact on pulp tissue dissolution. METHODS: Six different brands of household bleach were bought from drugstores. These were compared with Chlor-XTRA and technical NaOCl solutions of controlled concentration and alkalinity regarding their chlorine content (wt% NaOCl), pH, alkaline capacity, osmolarity, surface tension (Wilhelmy plate method), and price. Bovine pulp tissue (n = 10 specimens per group) dissolution at 37°C by test and control solutions adjusted to 1.0% NaOCl was assessed. Reduction in tissue weight was compared between groups by one-way analysis of variance, followed by Bonferroni correction (P < .05). RESULTS: The pH of undiluted solutions ranged between 11.1 and 12.7. Batches of the same product differed in NaOCl content. No product contained more than an equivalent of 0.1 mol/L NaOH. One household bleach brand (Safeway Bleach Summit Fresh) was slightly alkalized; the other solutions under investigation were not. Osmolarity was similar between products. The surface tension of Chlor-XTRA and Safeway Bleach Summit Fresh was about half that of the other solutions. Tissue dissolution was statistically similar (P > .05) among all solutions. Price was about 100-fold higher per liter of Chlor-XTRA compared with household bleach. CONCLUSIONS: Other than its price, the Chlor-XTRA solution had no unique features. In contrast to an earlier report, reduced surface tension did not result in greater soft tissue dissolution by NaOCl.

Evaluation of overhead spray-applied sanitizers for the reduction of Salmonella on tomato surfaces.

UNLABELLED: Efficacy of sanitizers in an overhead spray and brush roller system was examined for reducing Salmonella on unwaxed, mature green tomatoes. Surface inoculated tomatoes were treated in the overhead spray system for 5, 15, 30, and 60 s. A sodium hypochlorite (NaOCl) study tested NaOCl (25, 50, and 100 mg/L) against a water control. A sanitizer study examined NaOCl (100 mg/L), chlorine dioxide (ClO2; 5 mg/L), peroxyacetic acid (PAA; 80 mg/L), and water. The overhead spray system was also compared to a scale-model flume. All NaOCl concentrations were significantly more effective at removing Salmonella than water and achieved at least a 3-log10 CFU/mL reduction at different treatment times (P < 0.05). NaOCl (100 mg/L) achieved a 4 ± 1.8 log10 CFU/mL reduction at 15 s. In the sanitizer study, NaOCl, ClO2, and PAA achieved at least a 3-log10 CFU/mL reduction at 15 s and between 3.9 and 5.5 log10 CFU/mL reductions at 30 to 60 s. NaOCl (100 mg/L) in the overhead spray system significantly reduced more Salmonella than in the flume at 15 to 60 s. NaOCl flume treatment only reached a 1.3 ± 1.1 log10 CFU/mL reduction at 15 s. Results of this study demonstrate the ability of sanitizers in the laboratory model overhead spray system to reduce Salmonella on tomato surfaces. An overhead spray system could be implemented instead of flumes to achieve higher pathogen reduction with less water and sanitizer use, thereby lowering packing costs. PRACTICAL APPLICATION: The use of a non-recirculating, overhead spray brush roller system could offer a cost effective and efficacious way of washing tomatoes. The use large communal dump tanks in tomato processing has been suspected as a source of contamination in the tomato processing process. If effective, the brush roller system could augment or possible replace currently used dump tanks.

Bleach treatment of sputum samples aids pulmonary tuberculosis screening among HIV-infected patients in Laos.

BACKGROUND: Laos has a high prevalence of tuberculosis (TB) and a slowly increasing prevalence of human immunodeficiency virus/acquired immunedeficiency syndrome (HIV/AIDS). Sputum smear microscopy is the only method currently available for routine screening of pulmonary TB, although it only detects one in three cases among persons living with HIV (PLWH). Bleach treatment of sputum samples (bleach method) has been shown to significantly improve the sensitivity of the test; however, its effectiveness in PLWH remains to be determined in Laos. OBJECTIVES: To determine the performance of the bleach method as a diagnostic tool for pulmonary TB in PLWH and to assess its cost-effectiveness in Laos. RESULTS: Of 174 sputum samples collected from 92 patients, 29 were culture-positive for Mycobacterium tuberculosis in 17 patients. The sensitivity of the direct method and the bleach method was respectively 59% and 93%, and specificity was 100% for both methods. The incremental cost-effectiveness ratio for screening an additional case was US$17.40. CONCLUSION: The bleach method is simple, cheap, easy to perform and cost-effective in PLWH. Its implementation in laboratories involved in routine screening of pulmonary TB among PLWH would allow practitioners to start the treatment of this life-threatening co-infection earlier.

Cost and financial sustainability of a household-based water treatment and storage intervention in Zambia.

Providing safe water to >1 billion people in need is a major challenge. To address this need, the Safe Water System (SWS) - household water treatment with dilute bleach, safe water storage, and behavior change - has been implemented in >20 countries. To assess the potential sustainability of the SWS, we analyzed costs in Zambia of "Clorin" brand product sold in bottles sufficient for a month of water treatment at a price of $0.09. We analyzed production, marketing, distribution, and overhead costs of Clorin before and after sales reached nationwide scale, and analyzed Clorin sales revenue. The average cost per bottle of Clorin production, marketing and distribution at start-up in 1999 was $1.88 but decreased by 82% to $0.33 in 2003, when >1.7 million bottles were sold. The financial loss per bottle decreased from $1.72 in 1999 to $0.24 in 2003. Net program costs in 2003 were $428,984, or only $0.04 per person-month of protection. A sensitivity analysis showed that if the bottle price increased to $0.18, the project would be self-sustaining at maximum capacity. This analysis demonstrated that efficiencies in the SWS supply chain can be achieved through social marketing. Even with a subsidy, overall program costs per beneficiary are low.

Cost-effectiveness of home-based chlorination and safe water storage in reducing diarrhea among HIV-affected households in rural Uganda.

Safe water systems (SWSs) have been shown to reduce diarrhea and death. We examined the cost-effectiveness of SWS for HIV-affected households using health outcomes and costs from a randomized controlled trial in Tororo, Uganda. SWS was part of a home-based health care package that included rapid diarrhea diagnosis and treatment of 196 households with relatively good water and sanitation coverage. SWS use averted 37 diarrhea episodes and 310 diarrhea-days, representing 0.155 disability-adjusted life year (DALY) gained per 100 person-years, but did not alter mortality. Net program costs were 5.21 dollars/episode averted, 0.62 dollars/diarrhea-day averted, and 1,252 dollars/DALY gained. If mortality reduction had equaled another SWS trial in Kenya, the cost would have been 11 dollars/DALY gained. The high SWS cost per DALY gained was probably caused by a lack of mortality benefit in a trial designed to rapidly treat diarrhea. SWS is an effective intervention whose cost-effectiveness is sensitive to diarrhea-related mortality, diarrhea incidence, and effective clinical management.

Collaboration, cholera, and cyclones: a project to improve point-of-use water quality in Madagascar.

In November 1999, CARE Madagascar, Population Services International (PSI), and the Centers for Disease Control and Prevention (CDC) selected 30 poor communities in urban Antananarivo as the target population for launch of the Safe Water System. The system consists of behavior change techniques along with point-of-use treatment and safe storage of water. The project was launched in March 2000, ahead of schedule, because a cholera epidemic struck Madagascar in January. Because of the enormous demand created by the cholera epidemic and by 3 cyclones that followed in the next 3 months, the project grew to national scale in less than a year. The combination of community mobilization and social marketing resulted in increased demand for and use of the Safe Water System.

Sodium hypochlorite and its use as an endodontic irrigant.

Sodium hypochlorite has been used as an endodontic irrigant for more than 70 years, and is now one of the most common solutions for this purpose. The chemical properties and production of commercial sodium hypochlorite are reviewed. Domestic bleaches and an infant sanitizer are compared from the point of view of cost and ease of use--Milton being recommended where a 1% solution is required. The cost of syringes and needles for endodontic irrigation is many times greater than the hypochlorite they contain, and total annual practice costs for hypochlorite are low. Brief guidelines for clinical use, storage, handling and disposal are included.