Fluoride supplements, dental caries and fluorosis: a systematic review

Control of Dental Caries in Children and Adolescents Using Fluoride: An Overview of Community-Level Fluoridation Methods

The maintenance of oral health is a crucial aspect of general well-being; however, a significant proportion of the worldwide population experiences a range of oral diseases. Dental caries is a highly prevalent non-communicable disease globally, especially in children and adolescents. Fluoride is involved in the control of dental caries, primarily by decreasing the critical pH for dental hard tissue dissolution and decreasing enamel solubility. Due to the substantial data supporting the efficacy of fluoride in controlling dental caries, many community-level fluoridation initiatives have been devised and executed as global public health preventive interventions. These initiatives encompass the fluoridation of water, salt, and milk. Water fluoridation is considered safe and effective when fluoride levels are maintained within the recommended range (0.6 to 1.1 mg/L). Salt fluoridation has a cariostatic potential similar to that of water fluoridation, and a fluoride concentration of 250 micrograms per gram in salt is not associated with an increased risk of developing dental fluorosis. However, there is currently an effort to reduce the consumption of table salt in order to mitigate the harmful effects of excessive salt consumption. It has been hypothesized that fluoride food supplementation, such as fluoridated milk, is associated with a decrease in caries experience in permanent teeth; however, the effect is not clear in primary teeth. Public-level fluoride interventions are more cost-effective than the operative care of caries lesions and limit the burden of care. The administration of fluorides should be conducted using safe methods, limiting ingestion, and adhering to the guidelines set by international and national health agencies in each country. This is particularly important when considering children with developing dentitions. Fluoride is an important tool in the control of dental caries, but it is crucial to combine it with good oral hygiene, a healthy diet, and regular visits to a dental professional to maintain long-term oral health.

Unraveling molecular characteristic of fluoride neurotoxicity on U87 glial-like cells: insights from transcriptomic and proteomic approach

The potential of fluoride (F) as a neurotoxicant in humans is still controversial in the literature. However, recent studies have raised the debate by showing different mechanism of F-induced neurotoxicity, as oxidative stress, energy metabolism and inflammation in the central nervous system (CNS). In the present study, we investigated the mechanistic action of two F concentration (0.095 and 0.22 μg/ml) on gene and protein profile network using a human glial cell in vitro model over 10 days of exposure. A total of 823 genes and 2,084 genes were modulated after exposure to 0.095 and 0.22 μg/ml F, respectively. Among them, 168 were found to be modulated by both concentrations. The number of changes in protein expression induced by F were 20 and 10, respectively. Gene ontology annotations showed that the main terms were related to cellular metabolism, protein modification and cell death regulation pathways, such as the MAP kinase (MAPK) cascade, in a concentration independent manner. Proteomics confirmed the changes in energy metabolism and also provided evidence of F-induced changes in cytoskeleton components of glial cells. Our results not only reveal that F has the potential to modulate gene and protein profiles in human U87 glial-like cells overexposed to F, but also identify a possible role of this ion in cytoskeleton disorganization.

Screening and Interventions to Prevent Dental Caries in Children Younger Than 5 Years: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force

IMPORTANCE

A 2014 review for the US Preventive Services Task Force (USPSTF) found that oral fluoride supplementation and topical fluoride use were associated with reduced caries incidence in children younger than 5 years.

OBJECTIVE

To update the 2014 review on dental caries screening and preventive interventions to inform the USPSTF.

DATA SOURCES

Ovid MEDLINE, the Cochrane Central Register of Controlled Trials, and the Cochrane Database of Systematic Reviews (to September 2020); surveillance through July 23, 2021.

STUDY SELECTION

Randomized clinical trials (RCTs) on screening, preventive interventions, referral to dental care; cohort studies on screening and referral; studies on diagnostic accuracy of primary care oral examination or risk assessment; and a systematic review on risk of fluorosis included in prior USPSTF reviews.

DATA EXTRACTION AND SYNTHESIS

One investigator abstracted data; a second checked accuracy. Two investigators independently rated study quality.

RESULTS

Thirty-two studies (19 trials, 9 observational studies, and 4 nonrandomized clinical intervention studies [total 106 694 participants] and 1 systematic review [19 studies]) were included. No study evaluated effects of primary care screening on clinical outcomes. One study (n = 258) found primary care pediatrician examination associated with a sensitivity of 0.76 (95% CI, 0.55 to 0.91) and specificity of 0.95 (95% CI, 0.92 to 0.98) for identifying a child with cavities, and 1 study found a risk assessment tool associated with sensitivity of 0.53 and specificity of 0.77 (n = 697, CIs not reported) for a child with future caries. No new trials of dietary fluoride supplementation were identified. For prevention, topical fluoride compared with placebo or no topical fluoride was associated with decreased caries burden (13 trials, n = 5733; mean caries increment [difference in decayed, missing, and filled teeth or surfaces], -0.94 [95% CI, -1.74 to -0.34]) and likelihood of incident caries (12 trials, n = 8177; RR, 0.80 [95% CI, 0.66 to 0.95]; absolute risk difference, -7%) in higher-risk populations or settings, with no increased fluorosis risk. Evidence on other preventive interventions was limited (education, xylitol) or unavailable (silver diamine fluoride), and no study directly evaluated primary care dentistry referral vs no referral.

CONCLUSIONS AND RELEVANCE

There was no direct evidence on benefits and harms of primary care oral health screening or referral to dentist. Dietary fluoride supplementation and fluoride varnish were associated with improved caries outcomes in higher-risk children and settings.

Comparison of oral health indicators between two places of endemic dental fluorosis in Jordan

INTRODUCTION

Excessive fluoride intake during tooth development causes dental fluorosis.

AIM

This study aimed to (1) determine the prevalence of dental fluorosis in association with fluoride concentrations in drinking water, (2) explore the effects of altitude on the severity of fluorosis in two towns with high fluoride levels in the drinking water, and (3) assess decayed, missing, and filled teeth (DMFT) and oral hygiene practices among participants.

MATERIAL AND METHODS

The sample consisted of 100 and 141 schoolchildren, aged 15.3 ± 1.4 and 16.1 ± 1.3 years, living in Ruwaished and Kuraymah, respectively. Oral examinations were carried out, and dental fluorosis was assessed using the Dean's index. The DMFT index was also used for assessment. Samples of drinking water were analyzed using a fluoride-ion selective electrode. SPSS was used to analyze the data.

RESULTS

Two-thirds (68.8%) of adults from Kuraymah had moderate to severe fluorosis, with only 7% being unaffected. In Ruwaished, 50% of the sample had severe fluorosis, 22% showed moderate fluorosis, and none were unaffected. The average DMFT scores were 3.18 ± 1.81 and 3.81 ± 1.41 for Kuraymah and Ruwaished, respectively. In both towns, males had significantly higher caries scores than females. Oral hygiene was poor, as 64% and 57% of the participants from Kuraymah and Ruwaished, respectively, did not brush their teeth. A significant correlation was found between poor oral hygiene and increased DMFT scores.

CONCLUSIONS

This study concluded that higher fluorosis incidence and severity were present in the higher-altitude location (Ruwaished). Moreover, this study also indicated that fluorosed teeth are not immune to caries, and the preventive management of dental fluorosis should be directed to de-fluoridation of drinking water in endemic areas.

In Vitro Evaluation of the Apoptotic, Autophagic, and Necrotic Molecular Pathways of Fluoride

Prolonged exposure to high doses of fluoride causes chronic poisoning called fluorosis, which affects many tissues and causes serious health problems. This study was planned to investigate the apoptotic, autophagic, and necrotic molecular pathways of fluoride. Sodium fluoride (NaF) was administered to normal rat kidney epithelial (NRK-52E) cells. The NaF IC₅₀ value was determined using the MTT assay. The expression of the genes in the autophagic, apoptotic, and necrotic pathways was determined by real-time PCR. It was determined that there were significant changes in NaF-induced molecular pathways depending on the time. There were no increases in apoptotic and necrotic pathway markers except for Atg3, an autophagy gene, at the 3rd and the 12th hours. However, there was an induction in all cell death signaling pathways at 24 h. The molecular mechanisms demonstrated NaF-induced cellular death in the NRK-52E cell line. It was concluded that these molecular mechanisms were activated with NaF, and different mechanisms accelerated the cellular death at the 24th hour.

Therapeutic effect of a novel bioactive glass-ceramics on early caries lesions: a single-center, randomized controlled clinical trial

OBJECTIVES

To investigate the therapeutic effect of a novel bioactive glass-ceramics (BGC) called Huaxi BGC (HX-BGC) on early caries lesions.

MATERIALS AND METHODS

A total of 195 patients who meeting inclusion criteria were recruited and randomized to three groups in a 1:1:1 ratio. The patients in the treatment group received fluoride varnish which contained 5% sodium fluoride (NaF) or distilled water which contained 7.5% HX-BGC once a month for 3 months, and the control group received placebos. Quantitative light-induced fluorescence (QLF) images were taken at baseline and at the 1-month and 3-month follow-ups.

RESULTS

The three groups had similar baseline characteristics, including age, gender, and QLF parameters (ΔF, area, and ΔQ). Compared with baseline, the ΔQ values were significantly decreased in the HX-BGC and NaF groups at 1 and 3 months (p<0.005), while no statistically significant changes were found in that of the control group. After adjusting for baseline measurements, both of the 5% NaF and 7.5% HX-BGC showed a significant therapeutic effect in the treatment of initial enamel lesions at 1 month and 3 months, when compared to those receiving placebos (ΔQ, p<0.05). Moreover, the ΔQ value of the HX-BGC group decreased by a slightly more amount than that of the NaF group at 1 month (p=0.048). Similar trends were also found for the values of ΔF and area.

CONCLUSION

Our results suggest that HX-BGC may serve as a promising bioactive material for the treatment of early caries lesions.

CLINICAL RELEVANCE

HX-BGC holds a great promise to be used as a novel bioactive material for the treatment of early caries lesions.

Dental Fluorosis according to Birth Cohort and Fluoride Markers in an Endemic Region of Colombia

Objectives

To analyze changes in the dental fluorosis (DF) incidence according to a birth cohort and explore current exposure to DF in a case series.

Methods

Repeated cross-sectional study of two periods: 2015 and 2018. Two standardized examiners registered DF using the Thylstrup-Fejerskov index in permanent teeth of children aged 7–18 years. Period and birth cohort frequencies were estimated by a generalized linear model, binomial family, and logarithmic link function. Period estimates are presented as prevalence ratios (PR) and birth cohort estimates as cumulative incidence ratios (RR); 95% confidence intervals and P values are reported. In a subsample of 37 volunteers (12.29 ± 2.63 years), the fluoride (F) concentration in toenails was measured using the HMDS diffusion method and an ion-specific electrode. Other samples from the local environment such as food, soil, and coal were also collected.

Results

In 274 children, we found that nonsignificant increases between periods (PR = 1.17; 95% CI: 0.89–1.55) were not explained by birth cohort effects. A total of 37.8% of the subsample had a toenail F concentration ≥2 μg F/g. The salty snacks and seasoning had the highest F concentrations among local environmental samples.

Conclusion

In this population with a high DF frequency according to birth cohort and the evaluated period, the study of soil, coal, and food samples indicated a continued F exposure. F concentration found in the toenails shows a moderate F exposure; nearly a third of the children and adolescents exceeded the adopted threshold of 2 μg F/g. It is important to monitor and explore changes in exposure in highly affected population.

Exogenous Intake of Fluorides in Caries Prevention: Benefits and Risks

Caries incidence and prevalence have decreased significantly over the last few decades due to widespread use of fluoride. However, an increase in the prevalence of dental fluorosis has been reported in both fluoridated and non-fluoridated communities. Care must be taken to ensure that a balance between the optimal fluoride preventive effect at the individual and community level and minimal risk of dental fluorosis is maintained. This review describes the main sources of fluoride intake that have been identified: fluoridated drinking water, dietary fluoride supplement, and topical forms comprising toothpastes, rinses, gels and varnishes. The cited data were taken from meta-analytic studies and reports from Cochrane database systematic reviews up to December 2019. Efficiency, but safety, of topically applied fluorides in individual home care is dependent on the degree of compliance of individuals/parents and on the level of competence of providers of preventive counselling. The broad spectrum of these resources allows individualization of fluoride prevention based on risk analysis of caries attack and taking into consideration other preventive measures.

The Concept of Sustainable Development of Modern Dentistry

This paper concerns the assessment of the current state of dentistry in the world and the prospects of its sustainable development. A traditional Chinese censer was adopted as the pattern, with a strong and stable support on three legs. The dominant diseases of the oral cavity are caries and periodontal diseases, with the inevitable consequence of toothlessness. From the caries 3.5–5 billion people suffer. Moreover, each of these diseases has a wide influence on the development of systemic complications. The territorial range of these diseases and their significant differentiation in severity in different countries and their impact on disability-adjusted life years index are presented (DALY). Edentulousness has a significant impact on the oral health-related quality of life (OHRQoL). The etiology of these diseases is presented, as well as the preventive and therapeutic strategies undertaken as a result of modifying the Deming circle through the fives’ rules idea. The state of development of Dentistry 4.0 is an element of the current stage of the industrial revolution Industry 4.0 and the great achievements of modern dental engineering. Dental treatment examples from the authors’ own clinical practice are given. The systemic safety of a huge number of dentists in the world is discussed, in place of the passive strategy of using more and more advanced personal protective equipment (PPE), introducing our own strategy for the active prevention of the spread of pathogenic microorganisms, including SARS-CoV-2. The ethical aspects of dentists’ activity towards their own patients and the ethical obligations of the dentist community towards society are discussed in detail. This paper is a polemic arguing against the view presented by a group of eminent specialists in the middle of last year in The Lancet. It is impossible to disagree with these views when it comes to waiting for egalitarianism in dental care, increasing the scope of prevention and eliminating discrimination in this area on the basis of scarcity and poverty. The views on the discrimination of dentistry in relation to other branches of medicine are far more debatable. Therefore, relevant world statistics for other branches of medicine are presented. The authors of this paper do not agree with the thesis that interventional dental treatment can be replaced with properly implemented prophylaxis. The final remarks, therefore, present a discussion of the prospects for the development of dentistry based on three pillars, analogous to the traditional Chinese censer obtaining a stable balance thanks to its three legs. The Dentistry Sustainable Development (DSD) > 2020 model, consisting of Global Dental Prevention (GDP), Advanced Interventionist Dentistry 4.0 (AID 4.0), and Dentistry Safety System (DSS), is presented.

Fluoride network and circular economy as potential model for sustainable development-A review

Fluorine is the most reactive elements among the halogen group and commonly and ubiquitously occurs as fluoride in nature. The industrial processes produce fluoride by-products causing the increase of unwanted environmental levels and consequently posing risk on human and environmental health worldwide. This review gives a fundamental understanding of fluoride networks in the industrial processes, in the geological and hydrological transport, and in the biological sphere. Numerous biological pathways of fluoride also increase the risk of exposure. Literature shows that various environmental levels of fluoride due to its chemical characteristics cause bioaccumulation resulting in health deterioration among organisms. These problems are aggravated by emitted fluoride in the air and wastewater streams. Moreover, the current waste disposal dependent on incineration and landfilling superpose to the problem. In our analysis, the fluoride material flow model still follows a linear economy and reuse economy to some extent. This flow model spoils resources with high economic potential and worsens environmental problems. Thus, we intend a shift from the conventional linear economy to a circular economy with the revival of three-dimensional objectives of sustainable development. Linkages between key dimensions of the circular economy to stimulate momentum for perpetual sustainable development are proposed to gain economic, environmental and social benefits.

Review of Fluoride Intake and Appropriateness of Current Guidelines

Since the classical epidemiological studies by Dean, it has been known that there should be an optimum level of exposure to fluoride that would be able to provide the maximum protection against caries, with minimum dental fluorosis. The "optimal" daily intake of fluoride for children (0.05-0.07 mg per kilogram bodyweight) that is still accepted worldwide was empirically determined. In the present review, we discuss the appropriateness of the current guidance for fluoride intake, in light of the windows of susceptibility to caries and fluorosis, the modern trends of fluoride intake from multiple sources, individual variations in fluoride metabolism, and recent epidemiological data. The main conclusion is that it is very difficult to think about a strict recommendation for an "optimal" range of fluoride intake at the individual level in light of existing knowledge of 1) the mechanisms of action of fluoride to control caries, 2) the mechanisms involved in dental fluorosis development, 3) the distinct factors that interfere in the metabolism of fluoride, and 4) the windows of susceptibility to both dental caries and fluorosis development. An "optimal" range of fluoride intake is, however, desirable at the population level to guide programs of community fluoridation, but further research is necessary to provide additional support for future decisions on guidance in this area. This list includes the effect of factors affecting fluoride metabolism, clinical trials on the effectiveness of low-fluoride dentifrices to prevent caries in the primary dentition, and validation of biomarkers of exposure to fluoride.

Current Guidance for Fluoride Intake: Is It Appropriate?

The purpose of this report is to examine critically the appropriateness of the current guidance for fluoride intake in the population (0.05-0.07 mg F/kg bodyweight/d), consider whether changes to the current guidance are desirable, and suggest further research that will strengthen the evidence base for future decisions on guidance/advice in this area. The benefits and the risks of using fluoride particularly concern preschool children because it is at this age that excessive fluoride intake may result in dental fluorosis. Data from mostly cross-sectional studies show a wide variation in exposure and a considerable variation in the amount of fluoride ingested. Fluorosis, mostly mild, is commonly observed. For considering changes in current guidance, there is a need for more knowledge on the relationship between exposure to fluoride at an early age and the development of fluorosis. For that, prospective epidemiological studies with sufficiently large and representative samples of children are required. It is also important to study children in communities both with and without water fluoridation and to include populations where salt or milk fluoridation is used. There is also a need for professional agreement on acceptable levels of mild and moderate/severe fluorosis and a more comprehensive knowledge on the appreciation of mild fluorosis among the public.

Effects of Perinatal Fluoride Exposure on Short- and Long-Term Memory, Brain Antioxidant Status, and Glutamate Metabolism of Young Rat Pups

Exposure to fluoride (F) during the development affects central nervous system of the offspring rats which results in the impairment of cognitive functions. However, the exact mechanisms of F neurotoxicity are not clearly defined. To investigate the effects of perinatal F exposure on memory ability of young rat offspring, dams were exposed to 5 and 10 mg/L F during gestation and lactation. Additionally, we evaluated the possible underlying neurotoxic mechanisms implicated. The results showed that the memory ability declined in 45-day-old offspring, together with a decrease of catalase and glutamate transaminases activity in specific brain areas. The present study reveals that exposure to F in early stages of rat development leads to impairment of memory in young offspring, highlighting the alterations of oxidative stress markers as well as the activity of enzymes involved in the glutamatergic system as a possible mechanisms of neurotoxicity.

Dextran-Coated Zinc-Doped Hydroxyapatite for Biomedical Applications

Dextran-coated zinc-doped hydroxyapatite (ZnHApD) was synthesized by an adapted sol-gel method. The stability of ZnHApD nanoparticles in an aqueous solution was analyzed using ultrasonic measurements. The analysis of the evolution in time of the attenuation for each of the frequencies was performed. The X-ray diffraction (XRD) investigations exhibited that no impurity was found. The morphology, size and size distribution of the ZnHApD sample was investigated by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The TEM and SEM results showed that the ZnHApD particles have an ellipsoidal shape and a narrow distribution of sizes. The cell growth and toxicity of HEK-293 cells were investigated on the ZnHApD solution for four different concentrations and analyzed after 24 and 48 h. The ZnHApD solution presented a non-toxic activity against HEK-293 cells for all analyzed concentrations. The antibacterial assay revealed that all the tested microorganisms were inhibited by the ZnHApD dispersion after 24 and 48 h of incubation. It was observed that the effect of the ZnHApD solution on bacteria growth depended on the bacterial strain. The Porphyromonas gingivalis ATCC 33277 bacterial strain was the most sensitive, as a growth inhibition in the presence of 0.075 μg/mL ZnHApD in the culture medium was observed.

Changes in Older Adults' Oral Health and Disparities: 1999 to 2004 and 2011 to 2016

OBJECTIVES

To examine changes in tooth loss and untreated tooth decay among older low-income and higher-income US adults and whether disparities have persisted.

DESIGN

Sequential cross-sectional study using nationally representative data.

SETTING

The 1999 to 2004 and 2011 to 2016 National Health and Nutrition Examination Survey.

PARTICIPANTS

Noninstitutionalized US adults, aged 65 years and older (N = 3539 for 1999-2004, and N = 3514 for 2011-2016).

MEASUREMENTS

Differences in prevalence of tooth loss (having 19 teeth or fewer, 8 teeth or fewer, and no teeth) and untreated decay and mean number of decayed and missing teeth (DMT) between low- and high-income adults 65 years and older in each survey and changes between surveys. Adjusted prevalence and count outcomes were estimated with logistic and negative binomial regression models, respectively. Models controlled for sociodemographic characteristics and smoking status. Reported findings are significant at P < .05.

RESULTS

In 2011 to 2016, unadjusted prevalence of having 19 teeth or fewer, 8 teeth or fewer, no teeth, and untreated decay among low-income adults 65 years and older was 50.6%, 42.0%, 28.6%, and 28.6%, respectively. Multivariate analyses indicated that although most tooth loss measures improved between surveys for both income groups, tooth loss among low-income adults remained at almost twice that among higher-income adults. The disparity in untreated decay prevalence in 2011 to 2016, 15.2 percentage points (26.1% vs 10.9% for low vs high income) was twice that in 1999 to 2004, 8.5 percentage points (22.9% vs 14.4% for low vs high income). DMT decreased for both groups, with lower-income adults having about five more affected teeth in both surveys.

CONCLUSION

Tooth loss is decreasing, but differential access to restorative care by income appears to have increased.

Antimicrobial Activity of a Colloidal AgNP Suspension Demonstrated In Vitro against Monoculture Biofilms: Toward a Novel Tooth Disinfectant for Treating Dental Caries

A novel silver nanoparticle (AgNP) formulation was developed as a targeted application for the disinfection of carious dentine. Silver nitrate (AgNO₃) was chemically reduced using sodium borohydrate (NaBH₄) in the presence of sodium dodecyl sulfate (SDS) to form micelle aggregate structures containing monodisperse 6.7- to 9.2-nm stabilized AgNPs. AgNPs were characterized by measurement of electrical conductivity and dynamic light scattering, scanning electron microscopy, transmission electron microscopy, and inductively coupled plasma mass spectrometry. Antimicrobial activity of AgNPs was tested against planktonic cultures of representative gram-positive and gram-negative oral bacteria using well diffusion assays on tryptic soy broth media and monoculture biofilms grown with brain heart infusion ± sucrose anaerobically at 37°C on microtiter plates. Biofilm mass was measured by crystal violet assay. Effects were compared to silver diamine fluoride and chlorhexidine (negative controls) and 70% isopropanol (positive control) exposed cultures. In the presence of AgNPs, triplicate testing against Streptococcus gordonii DL1, C219, G102, and ATCC10558 strains; Streptococcus mutans UA159; Streptococcus mitis I18; and Enterococcus faecalis JH22 for planktonic bacteria, the minimum inhibitory concentrations were as low as 7.6 µg mL^-1 and the minimum bacteriocidal concentrations as low as 19.2 µg mL^-1 silver concentration. Microplate readings detecting crystal violet light absorption at 590 nm showed statistically significant differences between AgNP-exposed biofilms and where no antimicrobial agents were used. The presence of sucrose did not influence the sensitivity of any of the bacteria. By preventing in vitro biofilm formation for several Streptococcus spp. and E. faecalis, this AgNP formulation demonstrates potential for clinical application inhibiting biofilms.

Alterations in the memory of rat offspring exposed to low levels of fluoride during gestation and lactation: Involvement of the α7 nicotinic receptor and oxidative stress

Daily exposure to fluoride (F) depends mainly on the intake of this element with drinking water. When administered during gestation and lactation, F has been associated with cognitive deficits in the offspring. However, the mechanisms underlying the neurotoxicity of F remain obscure. In the current study, we investigated the effects of oral exposure to low levels of F during the gestational and lactation periods, on the memory of adult female rat offspring. We also considered a possible underlying neurotoxic mechanism. Our results showed that this exposure reduced step-down latency in the inhibitory avoidance task, and decreased both mRNA expression of the α7 nicotinic receptor (nAChR) and catalase activity in hippocampus. Our data indicates that low F concentrations administrated during gestation and lactation decrease the memory of 90-day-old female offspring. This suggests that the mechanism might be connected with an α7 nAChR deficit in the hippocampus, induced by oxidative stress.

The mitochondrial pathway is involved in sodium fluoride (NaF)-induced renal apoptosis in mice

The objective of the present study was to explore the molecular mechanism of apoptosis induced by sodium fluoride (NaF) in the mouse kidney by using the methods of flow cytometry, quantitative real-time polymerase chain reaction (qRT-PCR), western blotting, and experimental pathology. 240 four-week-old ICR mice were randomly divided into 4 groups and exposed to different concentrations of NaF (0 mg kg-1, 12 mg kg-1, 24 mg kg-1 and 48 mg kg-1) for a period of 42 days. The results demonstrated that NaF increased cell apoptosis and the depolarization of the mitochondrial membrane potential (MMP), and that the mitochondrial pathway was involved in NaF-induced apoptosis. Alteration of the mitochondrial pathway was characterized by significantly increasing mRNA and protein expression levels of cytosolic cytochrome c (Cyt c), the second mitochondrial activator of caspases/direct inhibitors of the apoptosis binding protein with low pI (Smac/Diablo), the serine protease high-temperature-requirement protein A2/Omi (HtrA2/Omi), the apoptosis inducing factor (AIF), endonuclease G (Endo G), cleaved-cysteine aspartate specific protease-9 (cleaved-caspase-9), cleaved-cysteine aspartate specific protease-3 (cleaved-caspase-3), Bcl-2 antagonist killer (Bak), Bcl-2 associated X protein (Bax), Bcl-2 interacting mediator of cell death (Bim), cleaved-poly-ADP-ribose polymerase (cleaved-PARP), p-p53, and decreasing mRNA and protein expression levels of B-cell lymphoma-2 (Bcl-2), Bcl-extra large (Bcl-xL), and X chromosome-linked inhibitors of apoptosis proteins (XIAPs). To our knowledge, the mitochondrial pathway is reported for the first time in NaF-induced apoptosis of the human or animal kidney. Also, this study provides novel insights for further studying fluoride-induced nephrotoxicity.

Fluoride supplementation (with tablets, drops, lozenges or chewing gum) in pregnant women for preventing dental caries in the primary teeth of their children

BACKGROUND

Dental caries (tooth decay) is one of the most common chronic childhood diseases. Caries prevalence in most industrialised countries has declined among children over the past few decades. The probable reasons for the decline are the widespread use of fluoride toothpaste, followed by artificial water fluoridation, oral health education and a slight decrease in sugar consumption overall. However, in regions without water fluoridation, fluoride supplementation for pregnant women may be an effective way to increase fluoride intake during pregnancy. If fluoride supplements taken by pregnant women improve neonatal outcomes, pregnant women with no access to a fluoridated drinking water supply can obtain the benefits of systemic fluoridation.

OBJECTIVES

To evaluate the effects of women taking fluoride supplements (tablets, drops, lozenges or chewing gum) compared with no fluoride supplementation during pregnancy to prevent caries in the primary teeth of their children.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 25 January 2017); the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 11) in the Cochrane Library (searched 25 January 2017); MEDLINE Ovid (1946 to 25 January 2017); Embase Ovid (1980 to 25 January 2017); LILACS BIREME Virtual Health Library (Latin American and Caribbean Health Science Information database; 1982 to 25 January 2017); and CINAHL EBSCO (Cumulative Index to Nursing and Allied Health Literature; 1937 to 25 January 2017). We searched the US National Institutes of Health Ongoing Trials Register (ClinicalTrials.gov) and the World Health Organization International Clinical Trials Registry Platform for ongoing trials to 25 January 2017. No restrictions were placed on the language or date of publication when searching the electronic databases.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of fluoride supplements (tablets, drops, lozenges or chewing gum) administered to women during pregnancy with the aim of preventing caries in the primary teeth of their children.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the titles and abstracts (when available) of all reports identified through electronic searches. Two review authors independently extracted data and assessed risk of bias, as well as evaluating overall quality of the evidence utilising the GRADE approach. We could not conduct data synthesis as only one study was included in the analysis.

MAIN RESULTS

Only one RCT met the inclusion criteria for this review. This RCT showed no statistical difference on decayed or filled primary tooth surfaces (dfs) and the percentage of children with caries at 3 years (risk ratio (RR) 1.46, 95% confidence interval (CI) 0.75 to 2.85; participants = 938, very low quality of evidence) and 5 years old (RR 0.84, 95% CI 0.53 to 1.33; participants = 798, very low quality of evidence). The incidence of fluorosis at 5 years was similar between the group taking fluoride supplements (tablets) during the last 6 months of pregnancy and the placebo group.

AUTHORS' CONCLUSIONS

There is no evidence that fluoride supplements taken by women during pregnancy are effective in preventing dental caries in their offspring.

The history of public health use of fluorides in caries prevention

AIM

The aim of our study was to chronologically analyse various public health measures of fluoride use in caries prevention.

METHODS

We systematically searched the PubMed database on the preventive role of fluorides in public health, published from 1984 to 2014. The search process was divided into four steps, where inclusion and exclusion criteria were defined. Qualitative methodology was used for the article analysis. In the research process, the described forms of F use, diversity of the described F agents, and the observed population group were analysed.

RESULTS

In our systematic review, 40 relevant reviews were revealed. Fluorides have been used in many different forms, but only a few studies showed their significant role in public health. Water fluoridation was the most important public health measure. In the recent decades, the number of studies on topical fluorides is constantly rising. The most extensively described topical forms of fluorides are professionally applied fluoride agents and fluoride toothpaste for home-use. The use of fluoride containing toothpaste in caries prevention is a safe and successful public health measure (PHM) if their use is widespread, and it is recommended for all. The results on other topical forms of fluorides are insufficient to be suggested as an important PHM.

CONCLUSIONS

The role of fluorides in public health prevention has changed in accordance with the knowledge about the fluoride cariostatic mechanism. Previously the most important pre-eruptive effect of fluorides was supplemented by the post eruptive effect. Abundant evidence exists to show the effectiveness of systemic and topical fluorides.

Enzymes in therapy of biofilm-related oral diseases

Biofilm-related infections of the oral cavity, including dental caries and periodontitis, represent the most prevalent health problems. For years, the treatment thereof was largely based on antibacterial chemical agents. Recently, however, there has been growing interest in the application of more preventive and minimally invasive biotechnological methods. This review focuses on the potential applications of enzymes in the treatment and prevention of oral diseases. Dental plaque is a microbial community that develops on the tooth surface, embedded in a matrix of extracellular polymeric substances of bacterial and host origin. Both cariogenic microorganisms and the key components of oral biofilm matrix may be the targets of the enzymes. Oxidative salivary enzymes inhibit or limit the growth of oral pathogens, thereby supporting the natural host defense system; polysaccharide hydrolases (mutanases and dextranases) degrade important carbohydrate components of the biofilm matrix, whereas proteases disrupt bacterial adhesion to oral surfaces or affect cell-cell interactions. The efficiency of the enzymes in in vitro and in vivo studies, advantages and limitations, as well as future perspectives for improving the enzymatic strategy are discussed.

Potential of Electrospun Nanofibers for Biomedical and Dental Applications

Electrospinning is a versatile technique that has gained popularity for various biomedical applications in recent years. Electrospinning is being used for fabricating nanofibers for various biomedical and dental applications such as tooth regeneration, wound healing and prevention of dental caries. Electrospun materials have the benefits of unique properties for instance, high surface area to volume ratio, enhanced cellular interactions, protein absorption to facilitate binding sites for cell receptors. Extensive research has been conducted to explore the potential of electrospun nanofibers for repair and regeneration of various dental and oral tissues including dental pulp, dentin, periodontal tissues, oral mucosa and skeletal tissues. However, there are a few limitations of electrospinning hindering the progress of these materials to practical or clinical applications. In terms of biomaterials aspects, the better understanding of controlled fabrication, properties and functioning of electrospun materials is required to overcome the limitations. More in vivo studies are definitely required to evaluate the biocompatibility of electrospun scaffolds. Furthermore, mechanical properties of such scaffolds should be enhanced so that they resist mechanical stresses during tissue regeneration applications. The objective of this article is to review the current progress of electrospun nanofibers for biomedical and dental applications. In addition, various aspects of electrospun materials in relation to potential dental applications have been discussed.

Differential diagnosis of dental fluorosis made by undergraduate dental students

OBJECTIVE

To check knowledge of undergraduate dental students to make diagnosis of dental fluorosis with varying degrees of severity and choose its appropriate treatment.

METHODS

Data were collected using a semi-structured questionnaire addressing knowledge of undergraduates based on ten images of mouths presenting enamel changes.

RESULTS

Only three images were correctly diagnosed by most undergraduates; the major difficulty was in establishing dental fluorosis severity degree.

CONCLUSION

Despite much information about fluorosis conveyed during the Dentistry training, as defined in the course syllabus, a significant part of the students was not able to differentiate it from other lesions; they did not demonstrate expertise as to defining severity of fluorosis and indications for treatment, and could not make the correct diagnosis of enamel surface changes.

Comments on “Dental lessons from past to present: ultrastructure and composition of teeth from plesiosaurs, dinosaurs, extinct and recent sharks” by A. Lübke, J. Enax, K. Loza, O. Prymak, P. Gaengler, H.-O. Fabritius, D. Raabe and M. Epple, RSC Adv., 2015, 5, 61612

The noted paper suggested that high fluoride levels in teeth of extinct animals proves the use of fluoroapatite when alive, but it is well-know that F⁻ increases during fossilization due to diagenetic passage of hydroxy to more stable fluoroapatite.

A systematic map of systematic reviews in pediatric dentistry--what do we really know?

OBJECTIVES

To identify, appraise and summarize existing knowledge and knowledge gaps in practice-relevant questions in pediatric dentistry.

METHODS

A systematic mapping of systematic reviews was undertaken for domains considered important in daily clinical practice. The literature search covered questions in the following domains: behavior management problems/dental anxiety; caries risk assessment and caries detection including radiographic technologies; prevention and non-operative treatment of caries in primary and young permanent teeth; operative treatment of caries in primary and young permanent teeth; prevention and treatment of periodontal disease; management of tooth developmental and mineralization disturbances; prevention and treatment of oral conditions in children with chronic diseases/developmental disturbances/obesity; diagnosis, prevention and treatment of dental erosion and tooth wear; treatment of traumatic injuries in primary and young permanent teeth and cost-effectiveness of these interventions. Abstracts and full text reviews were assessed independently by two reviewers and any differences were solved by consensus. AMSTAR was used to assess the risk of bias of each included systematic review. Reviews judged as having a low or moderate risk of bias were used to formulate existing knowledge and knowledge gaps.

RESULTS

Out of 81 systematic reviews meeting the inclusion criteria, 38 were judged to have a low or moderate risk of bias. Half of them concerned caries prevention. The quality of evidence was high for a caries-preventive effect of daily use of fluoride toothpaste and moderate for fissure sealing with resin-based materials. For the rest the quality of evidence for the effects of interventions was low or very low.

CONCLUSION

There is an urgent need for primary clinical research of good quality in most clinically-relevant domains in pediatric dentistry.

The combined use of Er,Cr:YSGG laser and fluoride to prevent root dentin demineralization

The use of erbium lasers to prevent caries in enamel has shown positive results. However, it is not known if Er,Cr:YSGG laser can also be used to increase acid resistance of root dentine, which is another dental tissue susceptible to the action of cariogenic bacteria.

OBJECTIVE

To analyze the effects of the Er,Cr:YSGG laser (λ=2.78 μm, 20 Hz) irradiation associated with 2% neutral sodium fluoride (NaF) to prevent root dentin demineralization.

MATERIAL AND METHODS

One hundred human root dentin samples were divided into 10 groups (G) and treated as follows: G1: no treatment; G2: NaF; G3: laser (4.64 J/cm2) with water cooling (WC=5.4 mL/min); G4: laser (4.64 J/cm2) without WC; G5: laser (8.92 J/cm2) with WC; G6: laser (8.92 J/cm2) without WC; G7: laser (4.64 J/cm2) with WC and NaF; G8: laser (4.64 J/cm2) without WC and NaF; G9: laser (8.92 J/cm2) with WC and NaF; G10: laser (8.92 J/cm2) without WC and NaF. The NaF gel was applied alone or after 4 min of irradiation. After 14 days of acid challenge, the samples were sectioned and the Knoop microhardness (KHN) test was done at different depths (30, 60, 90 and 120 μm) from the outer dentin surface. Data were analyzed by one-way ANOVA and Fisher's test (α=5%).

RESULTS

The results showed that G8 and G10 presented higher KHN than the G1 for the depths of 30 and 60 μm, indicating an increase of the acid resistance of the dentin in up to 35% (p<0.05).

CONCLUSIONS

The use of Er,Cr:YSGG laser irradiation at 4.64 J/ cm2 and 8.92 J/cm2 without water cooling and associated with 2% NaF can increase the acid resistance of human root dentin.

Effect of Diuretics on Salivary Flow, Composition and Oral Health Status: A Clinico-biochemical Study

Background:

Saliva represents an increasingly useful tool of diagnosis. Several factors such as salivary flow rates (SFRs) (unstimulated and stimulated) (U and S), pH, buffering capacity and consistency can be altered due to several disease processes or medications prescribed for various diseases. Alterations of SFRs, pH, buffering capacity and various ion concentrations can influence the pathogenesis of some of the oral diseases.

Aim:

Evaluation of the effect of diuretics on oral health status with regard to SFRs (U and S), pH, buffering capacity, total protein content, various ion concentrations and oral mucosal lesions.

Subjects and Methods:

A total of 100 patients were categorized into test group and control group based on usage of diuretics. Unstimulated and stimulated saliva were collected and evaluated for flow rates. Salivary pH was measured using pH meter. Buffering capacity was measured using Aranha's technique. Salivary Na⁺, K⁺ and Cl⁻ concentrations were measured using electrolyte analyzer CORNLEY ACCULYTE-3P in ion-selective electrode method. Salivary total protein content was measured by spectrophotometric method. Dental Caries and periodontal status were measured by using decayed, missing, filled teeth index and Russell's periodontal index respectively. Oral mucosal examination was carried out to identify the mucosal lesions.

Results:

The obtained results were subjected to statistical analysis using Statistical package for social sciences software (SPSS), version 16, IBM Company by Chi-square test and unpaired t-test. Highly significant P for alterations of SFR/U (P < 0.001), SFR/S (P < 0.001), pH (P < 0.001), Na⁺ concentration (P < 0.001), buffering capacity (P < 0.001) and moderate significance for Cl⁻ concentration (P < 0.01) were found. Alterations of total protein (P = 0.14) and K⁺ (P = 0.65) concentrations were not statistically significant. High prevalence was found for caries (P < 0.01), periodontal status (P < 0.001) and mucosal lesions (P < 0.01).

Conclusion:

Our study shows that diuretic medication significantly reduces SFRs (xerostomia) and alters salivary composition which may have an impact on the incidence of dental caries, periodontal diseases and mucosal lesion formation.

Toxic effects of sodium fluoride on cell proliferation and apoptosis of Leydig cells from young mice

The biological effects of fluoride on human health are often extensive, either beneficial or detrimental. Among the various effects of fluoride exposure in different organs, the reproductive tract is particularly susceptible to disruption by fluoride at a sufficient concentration. It has attracted much attention to the effect of sodium fluoride on male fertility, gestational female, and offspring. Herein, we applied a widespread natural compound sodium fluoride (NaF) and investigated the effects of acute NaF exposure on Leydig cells, including their proliferation, apoptosis, and signal pathway changes. Our results demonstrated that high dosage of NaF could inhibit cell proliferation by stress-induced apoptosis, which was confirmed by cellular and molecular evidences. We found that fluoride exposure affected the expression levels of stress response factors, signal transduction components, and apoptosis-related proteins, including caspase-3/caspase-9, B-cell lymphoma 2 (Bcl-2), and Bax. This study suggests that the complex effects of fluoride on Leydig cells are closely related to its dosage.

Fluoride decreased osteoclastic bone resorption through the inhibition of NFATc1 gene expression

Over the past two decades, fluoride effects on osteoclasts have been evaluated; however, its molecular mechanisms remain unclear. In this study, we investigated the effect of fluoride on osteoclast formation, function, and regulation using osteoclasts formed from mice bone marrow macrophages treated with the receptor activator of NF-κB ligand and macrophage colony-stimulating factor. Our data showed that fluoride levels ≤ 8 mg/L had no effect on osteoclast formation; however, it significantly reduced osteoclast resorption at 0.5 mg/L. Fluoride activity on bone resorption occurred through the inhibition of nuclear factor of active T cells (NFAT) c1 expression. Furthermore, the expression of its downstream genes, including the dendritic cell-specific transmembrane protein, c-Src, the d2 isoform of vacuolar (H+) ATPase v0 domain, matrix metalloproteinase 9, and cathepsin K were decreased, leading to impaired osteoclast acidification, reduced secretion of proteolytic enzymes, and decreased bone resorption. In summary, our results suggested that fluoride has different roles in osteoclast formation and function. Fluoride ≤ 8 mg/L did not impact osteoclast formation; however, it significantly decreased the resorption activity of newly formed osteoclasts. The molecular mechanism of fluoride action may involve inhibition of NFATc1 and its downstream genes.

Multivitamins/multiminerals in Switzerland: not as good as it seems

BACKGROUND

Multivitamin/multimineral (MVM) supplements are commonly consumed by the general population, but little is known regarding their composition and compliance with local regulations. We assessed the composition and compliance with regulations [no indication in the label of vitamin/minerals amounting <15% of the acceptable daily intake (ADI)] of MVM available in Switzerland.

METHODS

The composition of vitamin/minerals supplements was obtained from the Swiss drug compendium, the Internet, pharmacies, parapharmacies and supermarkets. MVM was defined as the presence of at least 5 vitamins and/or minerals.

RESULTS

Of the 254 vitamin/mineral supplements collected, 95 (37%) were considered as MVM. The most frequent vitamins were B₆ (73.7%), C (71.6%), B₂ (69.5%) and B₁ (67.4%); the least frequent were K (17.9%), biotin (51.6%), pantothene (55.8%) and E (56.8%). Approximately half of MVMs provided >150% of the ADI for vitamins. The most frequent minerals were zinc (66.3%), calcium (55.8%), magnesium (54.7%) and copper (48.4%), and the least frequent were fluoride (3.2%), phosphorous (17.9%), chrome (22.1%) and iodine (25%). More than two thirds of MVMs provided between 50 and 150% of the ADI for minerals, and few MVMs provided >150% of the ADI. While few MVMs provided <15% of the ADI for vitamins, a considerable fraction did so for minerals (32.7% for magnesium, 26.1% for copper and 22.6% for calcium).

CONCLUSION

There is a great variability regarding the composition of MVMs available in Switzerland. Several MVM do not comply with Swiss regulations, which calls for monitoring and corrective measures.

Water fluoridation: a critical review of the physiological effects of ingested fluoride as a public health intervention

Fluorine is the world's 13th most abundant element and constitutes 0.08% of the Earth crust. It has the highest electronegativity of all elements. Fluoride is widely distributed in the environment, occurring in the air, soils, rocks, and water. Although fluoride is used industrially in a fluorine compound, the manufacture of ceramics, pesticides, aerosol propellants, refrigerants, glassware, and Teflon cookware, it is a generally unwanted byproduct of aluminium, fertilizer, and iron ore manufacture. The medicinal use of fluorides for the prevention of dental caries began in January 1945 when community water supplies in Grand Rapids, United States, were fluoridated to a level of 1 ppm as a dental caries prevention measure. However, water fluoridation remains a controversial public health measure. This paper reviews the human health effects of fluoride. The authors conclude that available evidence suggests that fluoride has a potential to cause major adverse human health problems, while having only a modest dental caries prevention effect. As part of efforts to reduce hazardous fluoride ingestion, the practice of artificial water fluoridation should be reconsidered globally, while industrial safety measures need to be tightened in order to reduce unethical discharge of fluoride compounds into the environment. Public health approaches for global dental caries reduction that do not involve systemic ingestion of fluoride are urgently needed.

Impact of 24-month fluoride tablet program on children with disabilities in a non-fluoridated country

The aim of this study was to evaluate the caries preventive effects of a school-based fluoride tablet program in children with disabilities. Two hundred and seventeen children with disabilities were divided into two groups: the intervention group (IG) ingested 1.0mg fluoride tablet daily while the control group (CG) ingested a placebo. The initial oral examinations were conducted prior to fluoride intake and 24-month follow-up examinations were conducted to evaluate the effectiveness of fluoride tablet ingestion. The results from this study demonstrated significant reductions in the DMFT index (the sum of decayed, missing, and filled permanent teeth), 0.63, as well as the DMFS index (the sum of decayed, missing, and filled surfaces of the permanent dentition), 1.25, when compared with the CG. A statistically significant reduction in the DMFT index and DMFS index (30.42% and 36.84%, respectively) suggested an anti-cariogenic benefit to fluoride tablet administration. Greater caries reduction occurred on mesio-distal and bucco-lingual surfaces (53.27% and 52.57%, respectively). Fluoride tablets should be considered as a caries preventive strategy in school-based caries prevention programs for children with disabilities in fluoride deficient areas.

Preventing dental caries in children <5 years: systematic review updating USPSTF recommendation

BACKGROUND AND OBJECTIVE

Screening and preventive interventions by primary care providers could improve outcomes related to early childhood caries. The objective of this study was to update the 2004 US Preventive Services Task Force systematic review on prevention of caries in children younger than 5 years of age.

METHODS

Searching Medline and the Cochrane Library (through March 2013) and reference lists, we included trials and controlled observational studies on the effectiveness and harms of screening and treatments. One author extracted study characteristics and results, which were checked for accuracy by a second author. Two authors independently assessed study quality.

RESULTS

No study evaluated effects of screening by primary care providers on clinical outcomes. One good-quality cohort study found pediatrician examination associated with a sensitivity of 0.76 for identifying a child with cavities. No new trials evaluated oral fluoride supplementation. Three new randomized trials were consistent with previous studies in finding fluoride varnish more effective than no varnish (reduction in caries increment 18% to 59%). Three trials of xylitol were inconclusive regarding effects on caries. New observational studies were consistent with previous evidence showing an association between early childhood fluoride use and enamel fluorosis. Evidence on the accuracy of risk prediction instruments in primary care settings is not available.

CONCLUSIONS

There is no direct evidence that screening by primary care clinicians reduces early childhood caries. Evidence previously reviewed by the US Preventive Services Task Force found oral fluoride supplementation effective at reducing caries incidence, and new evidence supports the effectiveness of fluoride varnish in higher-risk children.

Aesthetic management of dental fluorosis

Significant numbers of patients visiting the paediatric dental clinics have aesthetically objectionable brown stains and desire treatment for them. Intrinsic tooth discolouration can be a significant aesthetic, and in some instances, functional, problem. Dental fluorosis, tetracycline staining, localised and chronological hypoplasia, and both amelogenesis and dentinogenesis imperfecta can all produce a cosmetically unsatisfactory dentition. The aetiology of intrinsic discolouration of enamel may sometimes be deduced from the patient's history, and one factor long associated with the problem has been a high level of fluoride intake. Optimal use of topical fluorides leads to a decrease in the caries prevalence but may show an increase in the prevalence of fluorosis staining because of metabolic alterations in the ameloblasts, causing a defective matrix formation and improper calcification. A 12-year-old male patient was screened at the dental clinic for routine dental care. He wanted us to remove and/or minimise the noticeable brown/yellow staining of his teeth. He requested the least invasive and most cost-effective treatment to change his smile. Various treatment modalities are present for the treatment of fluorosis stains. This report discusses the microabrasion technique in the patient having dental fluorosis.

Prophylactic effects of methyl-3-O-methyl gallate against sodium fluoride-induced oxidative stress in erythrocytes in vivo

OBJECTIVES

The purpose of this study was to demonstrate the effect of methyl-3-O-methyl gallate (M3OMG), a rare polyphenolic natural product with a potent in-vitro antioxidant effect, against sodium fluoride (NaF)-induced oxidative stress in rat erythrocytes in vivo.

METHODS

Male Wistar rats were treated daily with either M3OMG (10 and 20 mg/kg) obtained through synthesis, vitamin C (10 mg/kg) or vehicle intraperitoneally for 7 days. Oxidative stress was then induced by exposing animals to NaF (600 ppm) through drinking water for 7 days. At the end of intoxication period, rats were killed and erythrocytes isolated. The activity of antioxidant enzymes (catalase and superoxide dismutase) and levels of reduced glutathione and thiobarbituric acid reactive substances were measured in erythrocyte haemolysates.

RESULTS

NaF intoxication resulted in a 1.9-fold increase in erythrocyte lipid peroxidation associated with significant (P < 0.001) depletion of reduced glutathione level. Superoxide dismutase and catalase activity was suppressed by NaF treatment by 3.069 and 2.3 fold when compared with untreated control groups. Pretreatment of rats with M3OMG or vitamin C afforded protection against NaF-induced oxidative stress as assessed through the measured oxidant/antioxidant markers.

CONCLUSION

This finding provided in-vivo evidence for the therapeutic potential of M3OMG in combating fluoride-induced oxidative damage in cellular systems.

Effect of citrus lemon oil on growth and adherence of Streptococcus mutans

In order to exploit novel anticaries agents, we investigated the effects of citrus lemon oil (CLO), a type of natural product, on growth and adherence of the primary oral cariogenic bacteria Streptococcus mutans (S. mutans). The growth inhibitory effect was explored with a micro-dilution assay. Adherence was analyzed by colony counts on the respective surfaces and the adherence inhibition rate (AIR). Real time-PCR was used to investigate the effects of CLO on transcription of glucosyltransferase (Gtf) encoding genes, gtfB, C and D. Neson-Somogyi method was used to measure the effects of CLO on Gtf activity. The minimum inhibitory concentration of CLO against S. mutans was 4.5 mg/ml. The CLO effectively reduced the adherence of S. mutans on glass surface (the AIR were from 98.3 to 100 %, P > 0.05) and saliva-coated enamel surface (the AIR were from 54.8 to 79.2 %, P < 0.05). CLO effectively reduced the activity of Gtf and the transcription of gtfs in a dose dependent manner (P < 0.05). In conclusion, CLO can effectively inhibit the growth and the adherence to glass and saliva-coated enamel surfaces of S. mutans. It can also inhibit the transcription of gtfs, as well as the Gtf enzyme activity.

Position of the Academy of Nutrition and Dietetics: the impact of fluoride on health

It is the position of the Academy of Nutrition and Dietetics to support optimal systemic and topical fluoride as an important public health measure to promote oral health and overall health throughout life. Fluoride is an important element in the mineralization of bone and teeth. The proper use of topical and systemic fluoride has resulted in major reductions in dental caries and its associated disability. Dental caries remains the most prevalent chronic disease in children and affects all age groups of the population. The Centers for Disease Control and Prevention has named fluoridation of water as one of the 10 most important public health measures of the 21st century. Currently, >72% of the US population that is served by community water systems benefits from water fluoridation. However, only 27 states provide fluoridated water to more than three quarters of the state's residents on public water systems. Fluoride also plays a role in bone health. However, at this time, use of high doses of fluoride for osteoporosis prevention is considered experimental only. Dietetics practitioners should routinely monitor and promote the use of fluorides for all age groups.

Influence of a mouthwash containing hydroxyapatite microclusters on bacterial adherence in situ

OBJECTIVE

The aim of the present study was to investigate the efficacy of a new preparation in dental prophylaxis containing zinc-carbonate hydroxyapatite microclusters (Biorepair) for oral biofilm management.

METHODS AND MATERIALS

Initial biofilm formation was carried out in situ with bovine enamel slabs fixed to individual upper jaw splints worn by six subjects. Rinses with the customary preparation as well as with subfractions (hydroxyapatite microclusters in saline solution; liquid phase without particles) were adopted for 1 min in situ after 1 min of pellicle formation, and the bacterial colonization was recorded after 6 h and 12 h, respectively. Rinses with chlorhexidine served as a reference. The adherent microorganisms were quantified and visualized using DAPI staining and live-dead staining (BacLight). Furthermore, the effects on Streptococcus mutans bacteria were tested in vitro (BacLight).

RESULTS

Application of the customary preparation and of the separate components distinctly reduced the initial bacterial colonization of the enamel surface in situ as visualized and quantified with all techniques. After 12 h, 1.3 × 10(7) ± 2.0 × 10(7) bacteria/cm² were detected on unrinsed control samples with DAPI staining; 2.4 × 10(6) ± 3.3 × 10(6) after application of Biorepair (12 h after CHX-rinse; 1.3 × 10(5) ± 9.2 × 10(4)). Also, pure hydroxyapatite microclusters in saline solution (2.1 × 10(6) ± 3.0 × 10(6)) as well as the liquid phase without particles (5.1 × 10(5) ± 3.3 × 10(5)) reduced the amount of adherent bacteria. Furthermore, antimicrobial effects on S. mutans were observed in vitro.

CONCLUSION

The preparation is an effective compound for biofilm management in the oral cavity due to antiadherent and antibacterial effects.

CLINICAL RELEVANCE

The tested mouthrinse seems to be a reasonable amendment for dental prophylaxis.

Fluoride supplements (tablets, drops, lozenges or chewing gums) for preventing dental caries in children

BACKGROUND

Dietary fluoride supplements were first introduced to provide systemic fluoride in areas where water fluoridation is not available. Since 1990, the use of fluoride supplements in caries prevention has been re-evaluated in several countries.

OBJECTIVES

To evaluate the efficacy of fluoride supplements for preventing dental caries in children.

SEARCH METHODS

We searched the Cochrane Oral Health Group's Trials Register (to 12 October 2011), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 3), MEDLINE via OVID (1950 to 12 October 2011), EMBASE via OVID (1980 to 12 October 2011), WHOLIS/PAHO/MEDCARIB/LILACS/BBO via BIREME (1982 to 12 October 2011), and Current Controlled Trials (to 12 October 2011). We handsearched reference lists of articles and contacted selected authors.

SELECTION CRITERIA

We included randomised or quasi-randomised controlled trials comparing, with minimum follow-up of 2 years, fluoride supplements (tablets, drops, lozenges) with no fluoride supplement or with other preventive measures such as topical fluorides in children less than 16 years of age at the start. The main outcome was caries increment measured by the change in decayed, missing and filled tooth surfaces (DMFS).

DATA COLLECTION AND ANALYSIS

Two review authors, independently and in duplicate, assessed the eligibility of studies for inclusion, and carried out risk of bias assessment and data extraction. In the event of disagreement, we sought consensus and consulted a third review author. We contacted trial authors for missing information. We used the prevented fraction (PF) as a metric for evaluating the efficacy of the intervention. The PF is defined as the mean caries increment in controls minus mean caries increment in the treated group divided by mean caries increment in controls. We conducted random-effects meta-analyses when data could be pooled. We assessed heterogeneity in the results of the studies by examining forest plots and by using formal tests for homogeneity. We recorded adverse effects (fluorosis) when the studies provided relevant data.

MAIN RESULTS

We included 11 studies in the review involving 7196 children.In permanent teeth, when fluoride supplements were compared with no fluoride supplement (three studies), the use of fluoride supplements was associated with a 24% (95% confidence interval (CI) 16 to 33%) reduction in decayed, missing and filled surfaces (D(M)FS). The effect of fluoride supplements was unclear on deciduous or primary teeth. In one study, no caries-inhibiting effect was observed on deciduous teeth while in another study, the use of fluoride supplements was associated with a substantial reduction in caries increment.When fluoride supplements were compared with topical fluorides or with other preventive measures, there was no differential effect on permanent or deciduous teeth.The review found limited information on the adverse effects associated with the use of fluoride supplements.

AUTHORS' CONCLUSIONS

This review suggests that the use of fluoride supplements is associated with a reduction in caries increment when compared with no fluoride supplement in permanent teeth. The effect of fluoride supplements was unclear on deciduous teeth. When compared with the administration of topical fluorides, no differential effect was observed. We rated 10 trials as being at unclear risk of bias and one at high risk of bias, and therefore the trials provide weak evidence about the efficacy of fluoride supplements.

Urinary fluoride concentration in children with disabilities following long-term fluoride tablet ingestion

Urine is the most commonly utilized biomarker for fluoride excretion in public health and epidemiological studies. Approximately 30-50% of fluoride is excreted from urine in children. Urinary fluoride excretion reflects the total fluoride intake from multiple sources. After administering fluoride tablets to children with disabilities, urinary fluctuation patterns should be investigated. The purpose of this study was to monitor the short and long term fluctuating patterns of urinary fluoride concentration after fluoride tablets were ingested by children with disabilities. Children with disabilities aged 6-12 years old were selected randomly and were divided into three groups: Group A, 1.0mg fluoride tablet, Group B, 0.5mg fluoride tablet, and Group C, control group. The urine samples were collected in the morning (MU) and 2h after fluoride tablets were ingested (AU). Urine was collected on the day prior to fluoride intake (baseline), the first, the third, the fifth and the eighth day of fluoride ingestion for a short term, and once every 6 months for a total of 18 months for long-term observation. The AU sample showed statistically significantly higher concentrations of urine fluoride than those of the MU samples, and no statistically significant difference was noticed in the MU samples among the three groups. Group A showed the highest urinary fluoride concentration (UFC) among the three groups. UFC increased as ingested fluoride tablet dosage increased, and it returned to the baseline level on the following day and persisted throughout the study period.