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So far Masters RD. has created 996 blog entries.

Cost and effectiveness in American Health Care.

Since silicofluorides aren’t used in other coun-tries and are associated with a significant increase in the fre-quency of seven different diseases, stopping their use should be combined with screening and treating children for high body burdens of other toxins. As this suggestion indicates, Americans urgently need to focus on national health policy, can improve health at virtually no cost by ending silicofluoride use, and – as soon as possible – consider ways to increase public financing of medical care.

By |2018-07-26T16:26:19+00:00January 1st, 2009|Fluoride|

Considerations on optimal fluoride intake using dental fluorosis and dental caries outcomes–a longitudinal study.

OBJECTIVES:
The “optimal” intake of fluoride has been widely accepted for decades as between 0.05 and 0.07 mg fluoride per kilogram of body weight (mg F/kg bw) but is based on limited scientific evidence. The purpose of this paper is to present longitudinal fluoride intake data for children free of dental fluorosis in the early-erupting permanent dentition and free of dental caries in both the primary and early-erupting permanent teeth as an estimate of optimal fluoride intake.

METHODS:
Data on fluoride ingestion were obtained from parents of 602 Iowa Fluoride Study children through periodic questionnaires at the ages of 6 weeks; 3, 6, 9, 12, 16, 20, 24, 28, 32, and 36 months; and then at 6-month intervals thereafter. Estimates of total fluoride intake at each time point were made by summing amounts from water, dentifrice, and supplements, as well as other foods and beverages made with, or containing, water. Caries data were obtained from examinations of children at ages 5 and 9 years, whereas fluorosis data were obtained from examinations of children only at age 9 years.

RESULTS:
The estimated mean daily fluoride intake for those children with no caries history and no fluorosis at age 9 years was at, or below, 0.05 mg F/kg bw for nearly all time points through the first 48 months of life, and this level declined thereafter. Children with caries had generally slightly less intakes, whereas those with fluorosis generally had slightly higher intakes.

CONCLUSIONS:
Given the overlap among caries/fluorosis groups in mean fluoride intake and extreme variability in individual fluoride intakes, firmly recommending an “optimal” fluoride intake is problematic.

Fluoride toothpastes for preventing dental caries in children and adolescents.

MAIN RESULTS:
Seventy-four studies were included. For the 70 that contributed data for meta-analysis (involving 42,300 children) the D(M)FS pooled PF was 24% (95% confidence interval (CI), 21 to 28%; p<0.0001). This means that 1.6 children need to brush with a fluoride toothpaste (rather than a non-fluoride toothpaste) over three years to prevent one D(M)FS in populations with caries increment of 2.6 D(M)FS per year. In populations with caries increment of 1.1 D(M)FS per year, 3.7 children will need to use a fluoride toothpaste for three years to avoid one D(M)FS. There was clear heterogeneity, confirmed statistically (p<0.0001). The effect of fluoride toothpaste increased with higher baseline levels of D(M)FS, higher fluoride concentration, higher frequency of use, and supervised brushing, but was not influenced by exposure to water fluoridation. There is little information concerning the deciduous dentition or adverse effects (fluorosis).

REVIEWER’S CONCLUSIONS:
Supported by more than half a century of research, the benefits of fluoride toothpastes are firmly established. Taken together, the trials are of relatively high quality, and provide clear evidence that fluoride toothpastes are efficacious in preventing caries.

By |2018-07-26T15:40:41+00:00January 1st, 2009|Fluoride|

Investigation of contact allergy to dental metals in 206 patients.

BACKGROUND:
Contact allergy to dental materials is poorly understood; clinical manifestations are heterogeneous.

OBJECTIVE:
To analyse positive patch test reactions to metals (as their alloys or salts) used in dentistry together with clinical symptoms and possible relevance to dental fillings.

METHODS:
We retrospectively analysed 206 patients who underwent patch testing with metals used in dentistry because of suspected contact allergy to them.

RESULTS:
Twenty-eight of 206 patients had positive patch test reactions to metals used in dentistry. The number of positive patch test reactions was highest for gold sodium thiosulfate, palladium chloride, and nickel sulfate (n = 10, respectively), followed by amalgam, ammoniated mercury, and cobalt chloride (n = 4, respectively) and amalgam-mixed metals (including copper, tin, zinc, and silicon), and ammonium tetrachloroplatinate (n = 1). Only 14 (7%) of 206 patients had a clinically relevant contact allergy with conditions of the oral mucosa (n = 7 with lichen planus and n = 7 with stomatitis) and positive patch test reactions to dental metals containing the suspected allergen. Improvement of symptoms was assessed in one patient with amalgam contact allergy 2 weeks after removal of dental fillings.

CONCLUSIONS:
Clinically relevant contact allergies to dental metals are infrequent. Gold sodium thiosulfate and palladium chloride presented the most frequent contact allergens.

By |2018-07-30T15:38:20+00:00January 1st, 2009|Mercury|

An evaluation of replacement rates for posterior resin-based composite and amalgam restorations in US Navy and Marine Corps recruits.

RESULTS:
At the initial examination, 964 (15.2 percent) of amalgam restorations and 199 (17.4 percent) of resin-based composite restorations required re-treatment. Of those judged clinically acceptable, 14.2 percent of amalgam and 16.7 percent of resin-based composite restorations required replacement during the observation period. The authors found significant increases in replacement rates for resin-based composite restorations compared with amalgam restorations for replacement due to all causes (adjusted hazard ratio, 1.28; P < .05), as well as for replacement due to restoration failure (adjusted hazard ratio, 1.64; P < .01).

CONCLUSIONS:
About 30 percent of posterior restorations required replacement, either at the initial examination or during the subjects’ first years of military service. In a young military population, significantly more resin-based composite restorations in place at the initial examination will require replacement than will amalgam restorations. Multi-surface restorations had higher rates of replacement than did one-surface restorations, and subjects at high caries risk experienced significantly higher replacement rates than did those at low caries risk.

CLINICAL IMPLICATIONS:
The number of surfaces restored and subjects’ caries risk status may influence the longevity of resin-based composite and amalgam restorations.

By |2018-07-31T15:25:23+00:00January 1st, 2009|Mercury|

Chronic bacterial and viral infections in neurodegenerative and neurobehavioral diseases.

Often, patients with neurodegenerative or neurobehavioral diseases have chronic, neuropathic infections that could be important in disease inception, disease progression, or increasing the types or severities of signs and symptoms. Although controversial, the majority of patients with various neurodegenerative or neurobehavioral conditions, such as amyotrophic lateral sclerosis, multiple sclerosis, Alzheimer’s disease, Parkinson’s disease, and autistic spectrum disorders, show evidence of central nervous system or systemic  bacterial and viral infections. For example, using serology or polymerase chain reaction evidence of Chlamydia pneumoniae, Borrelia burgdorferi, Mycoplasma species, human herpesvirus-1 and -6, and other bacterial and viral infections revealed high infection rates that were not found in control subjects.

By |2018-07-27T00:10:00+00:00January 1st, 2008|Other|

The biocompatibility of resin-modified glass-ionomer cements for dentistry.

OBJECTIVES:
The biological effects of resin-modified glass-ionomer cements as used in clinical dentistry are described, and the literature reviewed on this topic.

METHODS:
Information on resin-modified glass-ionomers and on 2-hydroxyethyl methacrylate (HEMA), the most damaging substance released by these materials, has been collected from over 50 published papers. These were mainly identified through Scopus.

RESULTS:
HEMA is known to be released from these materials and has a variety of damaging biological properties, ranging from pulpal inflammation to allergic contact dermatitis. These are therefore potential hazards from resin-modified glass-ionomers. However, clinical results with these materials that have been reported to date are generally positive.

CONCLUSIONS/SIGNIFICANCE:
Resin-modified glass-ionomers cannot be considered biocompatible to nearly the same extent as conventional glass-ionomers. Care needs to be taken with regard to their use in dentistry and, in particular, dental personnel may be at risk from adverse effects such as contact dermatitis and other immunological responses.

By |2018-07-26T23:43:49+00:00January 1st, 2008|Fluoride|

Lesions of endodontic origin and risk of coronary heart disease

A paucity of epidemiologic research exists regarding systemic health consequences of endodontic disease. This study evaluated whether incident radiographically evident lesions of endodontic origin were related to development of coronary heart disease (CHD) among 708 male participants in the VA Dental Longitudinal Study. At baseline and every three years for up to 32 years, participants (who were not VA patients) received complete medical and dental examinations, including full-mouth radiographs. Cox regression models estimated the relationship between incident lesions of endodontic origin and time to CHD diagnosis. Among those < or = 40 years old, incident lesions of endodontic origin were significantly associated with time to CHD diagnosis (p < 0.05), after adjustment for covariates of interest, with hazard ratios decreasing as age increased. Among those > 40 years old, no statistically significant association was observed. These findings are consistent with research that suggests relationships between chronic periodontal inflammation and the development of CHD, especially among younger men.

Comparison of nanoparticle filtration performance of NIOSH-approved and CE-marked particulate filtering facepiece respirators

The National Institute for Occupational Safety and Health (NIOSH) and European Norms (ENs) employ different test protocols for evaluation of air-purifying particulate respirators commonly referred to as filtering facepiece respirators (FFR). The relative performance of the NIOSH-approved and EN-certified ‘Conformité Européen’ (CE)-marked FFR is not well studied. NIOSH requires a minimum of 95 and 99.97% efficiencies for N95 and P100 FFR, respectively; meanwhile, the EN requires 94 and 99% efficiencies for FFRs, class P2 (FFP2) and class P3 (FFP3), respectively. To better understand the filtration performance of NIOSH- and CE-marked FFRs, initial penetration levels of N95, P100, FFP2 and FFP3 respirators were measured using a series of polydisperse and monodisperse aerosol test methods and compared. Initial penetration levels of polydisperse NaCl aerosols [mass median diameter (MMD) of 238 nm] were measured using a method similar to the NIOSH respirator certification test method. Monodisperse aerosol penetrations were measured using silver particles for 4-30 nm and NaCl particles for 20-400 nm ranges. Two models for each FFR type were selected and five samples from each model were tested against charge neutralized aerosol particles at 85 l min(-1) flow rate. Penetrations from the 238 nm MMD polydisperse aerosol test were <1% for N95 and FFP2 models and <0.03% for P100 and FFP3 models. Monodisperse aerosol penetration levels showed that the most penetrating particle size (MPPS) was in the 30-60 nm range for all models of FFRs tested in the study. Percentage penetrations at the MPPS were <4.28, <2.22, <0.009 and <0.164 for the N95, FFP2, P100 and FFP3 respirator models, respectively. The MPPS obtained for all four FFR types suggested particle capturing by electrostatic mechanism. Liquid isopropanol treatment of FFRs shifted the MPPS to 200-300 nm and dramatically increased polydisperse as well as monodisperse aerosol penetrations of all four FFR types indicating that all the four FFR types share filtration characteristics of electret filters. Electrostatic charge removal from all four FFR types also increased penetration levels of 400-1000 nm range particles. Particle penetration data obtained in this study showed that the eight models of NIOSH-approved N95 and P100 and CE-marked FFP2 and FFP3 respirators used in this study provided expected levels of laboratory filtration performance against nanoparticles.

By |2021-01-20T00:05:58+00:00January 1st, 2008|Other|

Interactions of human commensal bacteria with amalgam derived mercury: the science and its implications for infectious disease and neurotoxicology.

In summary, there is currently a renaissance of interest in the contributions of the commensal microbiota to many aspects of health and disease from digestion to the development of the immune system and even to effects on the central nervous system (Yan and Polk, 2004; Kanauchi et al., 2005; Macdonald and Monteleone, 2005). One traditional area upon which this new perspective has yet to impinge is toxicology. The vigorous metabolism of all forms of Hg by bacterial members of the commensal microbiota is a rich example of what our small fellow travelers can marshal for their defense against the toxic agents to which we expose ourselves. Hopefully, toxicologists , especially those concerned with the widespread exposure to Hg from amalgam restorations, will begin to collaborate with microbiologists to take into account these bacterial processes (Fig. 1) in understanding the risks of amalgams and devising means to protect those with them and those having them removed.

By |2018-07-31T22:19:02+00:00January 1st, 2008|Mercury|
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