Effect of bottled fluoridated water to prevent dental caries in primary teeth: study protocol for a phase 2 parallel-group 3.5-year randomized controlled clinical trial (waterBEST).

BACKGROUND: Fluoridation of public water systems is known as a safe and effective strategy for preventing dental caries based on evidence from non-randomized studies. Yet 110 million Americans do not have access to a fluoridated public water system and many others do not drink tap water. This article describes the study protocol for the first randomized controlled trial (RCT) of fluoridated water that assesses its potential dental caries preventive efficacy when delivered in bottles. METHODS: waterBEST is a phase 2b proof-of-concept, randomized, quadruple-masked, placebo-controlled, parallel-group trial designed to estimate the potential efficacy of fluoridated versus non-fluoridated bottled water to prevent dental caries incidence in the first 4 years of life. Two hundred children living in eastern North Carolina, USA, and aged 2-6 months at screening are being allocated at random in a 1:1 ratio to receive fluoridated (0.7 mg/L F) or non-fluoridated bottled water sourced from two local public water systems. Throughout the 3.5-year intervention, study water is delivered monthly in 5-gallon bottles to each child's home with instructions to use it whenever the child consumes water as a beverage or in food preparation. Parents are interviewed quarterly to monitor children's water consumption and health. At annual visits, the presence of dental caries is evaluated with a dental screening examination. Clippings from fingernails and toenails are collected to quantify fluoride content as a biomarker of total fluoride intake. The primary endpoint is the number of primary tooth surfaces decayed, missing, or filled due to dental caries measured by the study dentist near the time of the child's fourth birthday. Tooth decay is assessed at the threshold of macroscopic enamel loss. For the primary aim, a least-squares, generalized linear model will estimate efficacy and its one-tailed, upper 80% confidence limit. DISCUSSION: waterBEST is the first evaluation of a randomized intervention of fluoridated drinking water in bottles to prevent dental caries in the primary dentition. This innovative method of delivering fluoridated water has the potential to prevent early childhood caries in a large segment of the US population that currently does not benefit from fluoridated public water. TRIAL REGISTRATION: ClinicalTrials.gov NCT04893681. Registered on March 2022. Last update posted on 10 October 2023. https://clinicaltrials.gov/study/NCT04893681?cond=Dental%20Caries%20in%20Children&term=fluoride&locStr=North%20Carolina,%20USA&country=United%20States&state=North%20Carolina&distance=50&rank=1.

Effect of bottled fluoridated water to prevent dental caries in primary teeth: study protocol for a phase 2 parallel group 3.5-year randomized controlled clinical trial (waterBEST).

Background: Fluoridation of public water systems is known as a safe and effective strategy for preventing dental caries based on evidence from non-randomized studies. Yet 110 million Americans do not have access to a fluoridated public water system and many others do not drink tap water. This article describes the study protocol for the first randomized controlled trial (RCT) of fluoridated water that assesses its potential dental caries preventive efficacy when delivered in bottles. Methods: waterBEST is a phase 2b proof-of-concept, randomized, quadruple-masked, placebo controlled, parallel group, trial designed to estimate the potential efficacy of fluoridated versus non-fluoridated bottled water to prevent dental caries incidence in the first four years of life. Two hundred children living in eastern North Carolina, USA, and aged 2-6 months at screening are being allocated at random in a 1:1 ratio to receive fluoridated (0.7 mg/L F) or non-fluoridated bottled water sourced from two local public water systems. Throughout the 3.5-year intervention, study water is delivered monthly in 5-gallon bottles to each child's home with instructions to use it whenever the child consumes water as a beverage or in food preparation. Parents are interviewed quarterly to monitor children's water consumption and health. At annual visits, the presence of dental caries is evaluated with a dental screening examination. Clippings from fingernails and toenails are collected to quantify fluoride content as a biomarker of total fluoride intake. The primary endpoint is the number of primary tooth surfaces decayed, missing, or filled due to dental caries measured by the study dentist near the time of the child's fourth birthday. Tooth decay is assessed at the threshold of macroscopic enamel loss. For the primary aim, a least-squares, generalized linear model will estimate efficacy and its one-tailed, upper 80% confidence limit. Discussion: waterBEST is the first evaluation of a randomized intervention of fluoridated drinking water in bottles to prevent dental caries in the primary dentition. This innovative method of delivering fluoridated water has potential to prevent early childhood caries in a large segment of the U.S. population that currently does not benefit from fluoridated public water.

Toxic and Essential Elements in Rice and Other Grains from the United States and Other Countries.

We determined the concentrations of toxic and essential elements in rice and other grains (lentils, barleys, beans, oats, wheat, and peas) grown in the United States (US) and other countries using Inductively Coupled Plasma Mass Spectrometry (ICPMS). Results showed that median concentrations (in µg/kg) for toxic elements in white rice from the US were 131, 2.8, and 6.5 for arsenic (As), lead (Pb), and cadmium (Cd), respectively. White rice from Thailand, India, and Italy showed higher median toxic elements concentrations (in µg/kg) of 155 for As, 3.6 for Pb, and 8.4 for Cd, than for white rice from the US. Brown rice from the US showed median concentrations (in µg/kg) of 217 (As), 4.5 (Pb), and 17.4 (Cd) while other grains showed median concentrations (in µg/kg) of 5.4, 4.6, and 6.7 for these elements, respectively. None of the samples exceeded the codex standards set for Pb (200 µg/kg in cereals and pulses) and Cd (100 µg/kg in cereals/pulses and 400 µg/kg in polished rice). However, brown rice and one white rice sample did exceed the codex standard for As (200 µg/kg). Essential elements were higher in other grains than in white and brown rice. These findings suggest that alternating or coupling rice with other grains in one's diet could reduce exposure to toxic metals while providing more essential elements to rice diet.

Deficiencies in mitochondrial dynamics sensitize Caenorhabditis elegans to arsenite and other mitochondrial toxicants by reducing mitochondrial adaptability.

Mitochondrial fission, fusion, and mitophagy are interlinked processes that regulate mitochondrial shape, number, and size, as well as metabolic activity and stress response. The fundamental importance of these processes is evident in the fact that mutations in fission (DRP1), fusion (MFN2, OPA1), and mitophagy (PINK1, PARK2) genes can cause human disease (collectively >1/10,000). Interestingly, however, the age of onset and severity of clinical manifestations varies greatly between patients with these diseases (even those harboring identical mutations), suggesting a role for environmental factors in the development and progression of certain mitochondrial diseases. Using the model organism Caenorhabditis elegans, we screened ten mitochondrial toxicants (2, 4-dinitrophenol, acetaldehyde, acrolein, aflatoxin B1, arsenite, cadmium, cisplatin, doxycycline, paraquat, rotenone) for increased or decreased toxicity in fusion (fzo-1, eat-3)-, fission (drp-1)-, and mitophagy (pdr-1, pink-1)-deficient nematodes using a larval growth assay. In general, fusion-deficient nematodes were the most sensitive to toxicants, including aflatoxin B1, arsenite, cisplatin, paraquat, and rotenone. Because arsenite was particularly potent in fission- and fusion-deficient nematodes, and hundreds of millions of people are chronically exposed to arsenic, we investigated the effects of these genetic deficiencies on arsenic toxicity in more depth. We found that deficiencies in fission and fusion sensitized nematodes to arsenite-induced lethality throughout aging. Furthermore, low-dose arsenite, which acted in a "mitohormetic" fashion by increasing mitochondrial function (in particular, basal and maximal oxygen consumption) in wild-type nematodes by a wide range of measures, exacerbated mitochondrial dysfunction in fusion-deficient nematodes. Analysis of multiple mechanistic changes suggested that disruption of pyruvate metabolism and Krebs cycle activity underlie the observed arsenite-induced mitochondrial deficits, and these disruptions are exacerbated in the absence of mitochondrial fusion. This research demonstrates the importance of mitochondrial dynamics in limiting arsenite toxicity by permitting mitochondrial adaptability. It also suggests that individuals suffering from deficiencies in mitodynamic processes may be more susceptible to the mitochondrial toxicity of arsenic and other toxicants.

From the Cover: Arsenite Uncouples Mitochondrial Respiration and Induces a Warburg-like Effect in Caenorhabditis elegans.

Millions of people worldwide are chronically exposed to arsenic through contaminated drinking water. Despite decades of research studying the carcinogenic potential of arsenic, the mechanisms by which arsenic causes cancer and other diseases remain poorly understood. Mitochondria appear to be an important target of arsenic toxicity. The trivalent arsenical, arsenite, can induce mitochondrial reactive oxygen species production, inhibit enzymes involved in energy metabolism, and induce aerobic glycolysis in vitro, suggesting that metabolic dysfunction may be important in arsenic-induced disease. Here, using the model organism Caenorhabditis elegans and a novel metabolic inhibition assay, we report an in vivo induction of aerobic glycolysis following arsenite exposure. Furthermore, arsenite exposure induced severe mitochondrial dysfunction, including altered pyruvate metabolism; reduced steady-state ATP levels, ATP-linked respiration and spare respiratory capacity; and increased proton leak. We also found evidence that induction of autophagy is an important protective response to arsenite exposure. Because these results demonstrate that mitochondria are an important in vivo target of arsenite toxicity, we hypothesized that deficiencies in mitochondrial electron transport chain genes, which cause mitochondrial disease in humans, would sensitize nematodes to arsenite. In agreement with this, nematodes deficient in electron transport chain complexes I, II, and III, but not ATP synthase, were sensitive to arsenite exposure, thus identifying a novel class of gene-environment interactions that warrant further investigation in the human populace.