Effects of long-term fluoride exposure are associated with oxidative biochemistry impairment and global proteomic modulation, but not genotoxicity, in parotid glands of mice

BACKGROUND

Fluoride has become widely used in dentistry because of its effectiveness in caries control. However, evidence indicates that excessive intake interferes with the metabolic processes of different tissues. Thus, this study aimed to investigate the effects of long-term exposure to F on the parotid salivary gland of mice, from the analysis of oxidative, proteomic and genotoxic parameters.

MATERIALS AND METHODS

The animals received deionized water containing 0, 10 or 50 mg/L of F, as sodium fluoride, for 60 days. After, parotid glands were collected for analysis of oxidative biochemistry, global proteomic profile, genotoxicity assessment and histopathological analyses.

RESULTS

The results revealed that exposure to fluoride interfered in the biochemical homeostasis of the parotid gland, with increased levels of thiobarbituric acid reactive species and reduced glutathione in the exposed groups; as well as promoted alteration of the glandular proteomic profile in these groups, especially in structural proteins and proteins related to oxidative stress. However, genotoxic assessment demonstrated that exposure to fluoride did not interfere with DNA integrity in these concentrations and durations of exposure. Also, it was not observed histopathological alterations in parotid gland.

CONCLUSIONS

Thus, our results suggest that long-term exposure to fluoride promoted modulation of the proteomic and biochemical profile in the parotid glands, without inducing damage to the genetic component. These findings reinforce the importance of rationalizing the use of fluorides to maximize their preventative effects while minimizing the environmental risks.

The value of the hedgehog signal in osteoblasts in fluoride-induced bone-tissue injury

OBJECTIVE

This study was designed to observe the expression of important hedgehog (Hh) signal factors in the bone tissue of rats with chronic fluorosis and cultured osteoblasts in order to investigate the role and significance of the Hh signal in fluoride-induced bone injury.

METHODS

Healthy Sprague-Dawley (SD) rats were randomly divided into four groups: the control group, the fluorosis group (F Group), the fluoride + blocker group (F + Cycl group: rats were treated with fluoride + cyclopamine), and the fluoride + blocker control group (F + DMSO group). After 6 months of intervention, the urinary fluoride content of rats in each group was detected. The primary osteoblasts of rats were selected for cell experiment, and the experiment was carried out after the cells were passaged from the second to the fourth generation.

RESULTS

The proliferation rate of primary rat osteoblasts presented time-affected and dose-affected relationships in a short time under treatment with a low dose of sodium fluoride (NaF), but the proliferation of osteoblasts was inhibited by long-term and high-dose NaF exposure. In the F group, the alkaline phosphatase (ALP) activity of osteoblasts increased gradually. The ALP activity was lower in the F + Cycl group than in the F group, and there was no significant difference between the F + DMSO group and F group. With the increase in fluoride exposure, the expression of Hh signal factors and osteogenic-related factor proteins increased gradually. The expressions of Indian hedgehog (Ihh), smoothened (Smo), Glioma-associated oncogene homolog (Gli) 2, and Runt-related transcription factor 2 (Runx2)in the F + Cycl group increased with the dose of fluoride but they were significantly inhibited compared with the F group. Compared with the control group, the content of urinary fluoride in the F group was significantly higher (P < 0.05), but there was no significant change in urinary fluoride content in the F + Cycl group and the F + DMSO group. Compared with the control group, the serum bone alkaline phosphatase (BALP) contents of rats in the other groups increased after 6 months' intake of fluoride water (P < 0.05). After drug blocking, the serum BALP content in the F + Cycl group was lower than that in the F + DMSO group (P < 0.05). The BALP content in the F + DMSO group was similar to that in the F group: it did not decrease. The mRNA expressions of Ihh, Smo, Gli2, and Runx2 in bone tissue of the F group were significantly higher than those in the control group (P < 0.05). After cyclopamine blocking, the expressions decreased (P < 0.05), but the differences between the F + DMSO group and F group were not statistically significant.

CONCLUSION

Hh signal plays an important role in fluoride-induced bone injury. The effective inhibition of cyclopamine is expected to be a new target for the treatment of skeletal damage caused by fluorosis.

Sodium Fluoride and Fluoride Contaminated Ground Water Induced Altered Reproductive Performances in Male Rats

Present study was undertaken to investigate the toxic effect of sodium fluoride (NaF)- and fluoride (F)-contaminated ground water on reproductive performances of male rats. Healthy adult male rats were categorised into three groups, first group of rats were served as control, whereas second group of rats were orally intubated with NaF (10 mg/kgbw/1 ml/rat) and third group of rats were allowed to drink F-contaminated ground water (5 mg/L) through drinking water bottles for 52 days. Exposure of NaF- and F-contaminated ground water caused significant decline in sperm motility, serum concentration of testosterone, and increase in sperm abnormality compared with controls. Further, significant histological alterations characterized with shrunken seminiferous tubules and degeneration of different stages of spermatogonial cells were observed in rats treated with NaF- and F-contaminated ground water. After the confirmation of toxic effect of F, these NaF- and F-contaminated ground water-treated male rats were allowed to mate with proven fertile untreated female rats to study the reproductive performances of male rats. There was a decline in parturition index, fertility index of male and female, gestation index and number of pups delivered in NaF-treated male rats compared with controls. However, gestation index and number of pups delivered were declined in F-contaminated ground water-treated male rats compared with controls. These results clearly indicate that F exposure affected the reproductive performances of male rats. The present study further revealed the fact that F-induced decline in testosterone levels, reduced sperm motility, and loss of spermatogonial cells affected the reproductive performances of male rats.

GSTO1 acts as a mediator in sodium fluoride-induced alterations of learning and memory related factors expressions in the hippocampus cell line

The mechanism of GSTO1, as a high-risk factor for neurological damage, in sodium fluoride (NaF)-induced learning and memory impairment remained still unclear. Hence, in this study, we used the siRNA-GSTO1 HT22 model to explore the effect of NaF and siRNA-GSTO1 on the viability, and proliferation rate of HT22 cells, as well as the mRNA and protein expression levels of cyclic adenosine monophosphate (cAMP) response element binding protein (CREB), neural cell adhesion molecule (NCAM), stem cell factor (SCF) and brain-derived neurotrophic factor (BDNF). The results of MTT showed that 10^-3, 10^-4, and 10^-5 moL/L sodium fluoride (NaF) exposure could significantly promote the proliferation of HT22 cells at 24 h, 36 h, and 48 h, respectively. In addition, our results showed that exposure to 10^-3, 10^-4, and 10^-5 moL/l NaF increased GSTO1 mRNA and protein expression, but decreased CREB and BDNF expression levels in a dose and time-dependent manner. The mRNA and protein expressions of GSTO1, CREB and BDNF were significantly decreased in the siRNA-GSTO1 and NaF + siRNA-GSTO1 group (P < 0.05). We have shown that various NaF doses affected the learning and memory ability by down-regulation the expressions of CREB, BDNF, NCAM and SCF. In summary, we concluded that GSTO1 plays a mediator role in NaF-induced neurological damage.

The Effect of Silver Diamine Fluoride in Preventing Caries in the Primary Dentition: A Systematic Review and Meta-Analysis

OBJECTIVES

To investigate whether silver diamine fluoride (SDF) is effective in preventing new caries lesions in primary teeth when compared to placebo or active treatments.

METHODS

Systematic review (CRD42016036963) of controlled clinical trials. Searches were performed in 9 electronic databases, 5 registers of ongoing trials, and reference lists of identified review articles. Two researchers carried out data extraction and quality appraisal independently. The primary outcome was the difference in caries increment (decayed, missing, and filled surfaces or teeth - dmfs or dmft) between SDF and control groups. These differences were pooled as weighted mean differences (WMD) and prevented fractions (PF).

RESULTS

Searches yielded 2,366 unique records; 6 reports of 4 trials that randomized 1,118 and analyzed 915 participants were included. Two trials compared SDF to no treatment, 1 compared SDF to placebo and sodium fluoride varnish (FV), and 1 compared SDF to high-viscosity glass ionomer cement (GIC). All studies had at least 1 domain with unclear or high risk of bias. After 24 months of follow-up, in comparison to placebo, no treatment, and FV, SDF applications significantly reduced the development of new dentin caries lesions (placebo or no treatment: WMD = -1.15, PF = 77.5%; FV: WMD = -0.43, PF = 54.0%). GIC was more effective than SDF after 12 months of follow-up but the difference between them was not statistically significant (WMD, dmft: 0.34, PF: -6.09%).

CONCLUSION

When applied to caries lesions in primary teeth, SDF compared to no treatment, placebo or FV appears to effectively prevent dental caries in the entire dentition. However, trials specifically designed to assess this outcome are needed.

Identification of miR-200c-3p as a major regulator of SaoS2 cells activation induced by fluoride

The skeletal lesion of fluoride has become a major concern in many countries due to its damage to bone and joints and even leading to disability. Skeletal fluorosis is characterized by disturbance of bone metabolism, aberrant proliferation and activation of osteoblasts is critical for the pathogenesis. However, the mechanism underlying the osteotoxicity of fluoride has not been clearly illustrated and there is still limited information on the role of miRNAs in skeletal fluorosis. In this study, we found that NaF promoted SaoS2 proliferation and activation by activating BMP4/Smad pathway. NaF increased expression of miR-200c-3p and miR-200c-3p inhibitor reduced activation of SaoS2 induced by NaF via targeting Noggin to repress BMP4/Smad. These findings suggested an important regulatory role of miR-200c-3p on BMP4/Smad pathway during skeletal fluorosis. MiR-200c-3p might be a novel therapeutic target for skeletal fluorosis.

Efficacy and safety of medical therapy for low bone mineral density in patients with Crohn disease: A systematic review with network meta-analysis

BACKGROUND

Low bone mineral density (BMD) is a frequent complication of inflammatory bowel disease (IBD), particularly in patients with Crohn disease (CD). The aim of our study is to determine the efficacy and safety of different drugs used to treat low BMD in patients with CD.

METHODS

PUBMED/MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials were searched for eligible studies. A random-effects model within a Bayesian framework was applied to compare treatment effects as standardized mean difference (SMD) with their corresponding 95% credible interval (CrI), while odds ratio (OR) was applied to compare adverse events with 95% CrI. The surface under the cumulative ranking area (SUCRA) was calculated to make the ranking of the treatments for outcomes.

RESULTS

Twelve randomized controlled trials (RCTs) were eligible. Compared with placebo, zoledronate (SMDs 2.74, 95% CrI 1.36-4.11) and sodium-fluoride (SMDs 1.23, 95% CrI 0.19-2.26) revealed statistical significance in increasing lumbar spine BMD (LSBMD). According to SUCRA ranking, zoledronate (SUCRA = 2.5%) might have the highest probability to be the best treatment for increasing LSBMD in CD patients among all agents, followed by sodium-fluoride (27%). For safety assessment, the incidence of adverse events (AEs) demonstrated no statistical difference between agents and placebo. The corresponding SUCRA values indicated that risedronate (SUCRA = 77%) might be the most safe medicine for low BMD in CD patients and alendronate ranked the worst (SUCRA = 16%).

CONCLUSIONS

Zoledronate might have the highest probability to be the best therapeutic strategy for increasing LSBMD. For the safety assessment, risedronate showed the greatest trend to decrease the risk of AEs. In the future, more RCTs with higher qualities are needed to make head-to-head comparison between 2 or more treatments.

Protective effects of blackberry and quercetin on sodium fluoride-induced oxidative stress and histological changes in the hepatic, renal, testis and brain tissue of male rat

BACKGROUND

Sodium fluoride (NaF) intoxication is associated with oxidative stress and altered antioxidant defense mechanism. The present study was carried out to evaluate the potential protective role of blackberry and quercetin (Q) against NaF-induced oxidative stress and histological changes in liver, kidney, testis and brain tissues of rats.

METHODS

The rats were allocated evenly to seven groups. The first group was maintained as the control, whereas groups 2, 3, 4, 5, 6 and 7 were administered blackberry juice (BBJ), Q, NaF, BBJ+NaF, Q+NaF and BBJ+Q+NaF, respectively, for a period of 30 days.

RESULTS AND CONCLUSIONS

NaF caused an elevation in lipid peroxidation level paralleled with significant decline in glutathione peroxidase, glutathione reductase, glutathione S-transferase, superoxide dismutase and catalase activities as well as the total antioxidant activity in liver, kidney, testes and brain. Some histopathological changes were detected in all tested tissues of the NaF treated group. Q and BBJ had successfully maintained normal histological architecture and mitigated the induction of oxidative stress caused by NaF. Q effectively reduced the elevation in thiobarbituric acid reactive substances level and restored the activities of antioxidant enzymes in liver, kidney, testis and brain. Less histopathological changes were observed in Q+NaF and BBJ+NaF treated groups. As a result, BBJ and Q significantly reduced NaF-induced oxidative and histological changes in rats. In the combination of BBJ and Q against NaF toxicity, the effects were more severe than from separate exposure, thus indicating that these flavonoids exhibited synergistic effects on all antioxidant and histological parameters.

Streptozotocin Aggravated Osteopathology and Insulin Induced Osteogenesis Through Co-treatment with Fluoride

The role of insulin in the mechanism underlying the excessive fluoride that causes skeletal lesion was studied. The in vitro bone marrow stem cells (BMSC) collected from Kunming mice were exposed to varying concentrations of fluoride with or without insulin. The cell viability and early differentiation of BMSC co-treated with fluoride and insulin were measured by using cell counting kit-8 and Gomori modified calcium-cobalt method, respectively. We further investigated the in vivo effects of varying dose of fluoride on rats co-treated with streptozotocin (STZ). Wistar rats were divided into six groups which included normal control, 10 mg fluoride/kg day group, 20 mg fluoride/kg day group, STZ control, STZ+10 mg fluoride/kg day group, and STZ+20 mg fluoride/kg day group. The rats were administered with sodium fluoride (NaF) by gavage with water at doses 10 and 20 mg fluoride/kg day for 2 months. In a period of one month, half of rats in every group were treated with streptozotocin (STZ) once through intraperitoneal injection at 52 mg/kg body weight. The serum glucose, HbA1c, and insulin were determined. Bone mineral content and insulin release were assessed. The results showed insulin combined with fluoride stimulated BMSC cell viability in vitro. The bone mineral content reduced in rats treated with higher dose of fluoride and decreased immensely in rat co-treated with fluoride and STZ. Similarly, a combination treatment of a high dose of fluoride and STZ decreased insulin sensitivity and activity. To sum up, these data indicated fluoride influenced insulin release, activity, and sensitivity. Furthermore, the insulin state in vivo interfered in the osteogenesis in turn and implied there was a close relation between insulin and bone pathogenesis in the mechanism of fluoride toxicity.

Sodium fluoride promotes apoptosis by generation of reactive oxygen species in human lymphocytes

Fluoride generated the attention of toxicologists due to its deleterious effects at high concentrations in human populations suffering from fluorosis and with in vivo experimental models. Interest in its undesirable effects has resurfaced due to the awareness that this element interacts with cellular systems even at low doses. This study focused on examining the adverse effects of inorganic fluoride (NaF) on human lymphocyte cells in vitro. Mitochondrial function, oxidative stress, cell cycle progression, and mode of cell death were combined with genotoxic endpoints. Data demonstrated that NaF at lower concentrations, although not significantly cytotoxic and genotoxic, induced oxidative stress leading to apoptotic cell death. The results also suggested that at low concentrations (<1 μg/ml), NaF may affect cell cycle progression. Taken together, our findings confirm earlier reports on mechanisms involved in NaF-induced apoptosis.

Physical exercise ameliorates the toxic effect of fluoride on the insulin-glucose system

Daily intake of water with fluoride concentrations >1.5 mg/l produces insulin resistance (IR). On the other hand, physical activity increases insulin sensitivity in the muscle. Therefore, the aim of this study was to evaluate the effect of physical activity on IR in rats treated with sodium fluoride (NaF) in drinking water. Sprague-Dawley rats were divided into three groups (n=10/group): Control (drinking water without NaF), NaF (drinking water with NaF 15 mg/l for 30 days), and Exercise (daily running on a treadmill for 60 min at 2.25 m/min and drinking water with NaF 15 mg/l for 30 days). IR was evaluated with the homeostasis model assessment-IR (HOMA-IR) index using fasting plasma levels of glucose and insulin. IR increased in rats treated with 15 mg/l NaF in drinking water. A decrease in IR was observed in rats that performed physical activity and drank water with 15 mg/l NaF; the Exercise group also showed an increase in the amounts of bone fluoride. The variation in the HOMA-IR values could be the consequence of variation in the sensitivity of tissues to insulin or decrease in plasma fluoride levels due to bone fluoride intake. These findings indicate that the performance of daily physical activity could reduce the negative effects of the chronic ingestion of NaF on glucose homeostasis.

[Dental fluorosis prevalence in Mexican localities of 27 states and the D.F.: six years after the publication of the Salt Fluoridation Mexican Official Regulation]

OBJECTIVE

To identify the prevalence and severity of dental fluorosis in communities located in 28 states of Mexico.

MATERIALS AND METHODS

The National Dental Caries Survey 2001 (NDCS2001) data base was analyzed. The information of 26,893 students, ages 12 and 15 years old, of 27 states and the Federal District was examined. Dean's dental fluorosis index was applied by standardized examiners. The fluorosis prevalence and the Community Fluorosis Index (FCI) were calculated.

RESULTS

The fluorosis prevalence was 27.9% (95% CI 24.4, 28.5). A statistical significance difference in the fluorosis prevalence was observed among the states studied (p < 0.0001). The lowest prevalence was detected in Morelos (3.2%) and the highest in Durango (88.8%). In 18 (64.3%) of the states included more than 90% of the participants showed very mild or lower levels of the dental fluorosis index. A low level of the FCI was found in the localities belonging to 19 (67.9%) of the states studied (FCI < 0.4). The lowest FCI was found in Colima, Yucatán and Morelos. The highest FCI were found in Durango, Zacatecas, Aguascalientes and San Luis Potosí (1 ≤ ICF). This information indicates that in these states dental fluorosis is a public health problem.

CONCLUSIONS

Two-thirds of the states had localities with low prevalence of dental fluorosis; however, approximately, one-third of the states investigated the fluorosis levels showed the need of a reduction in fluoride exposure among the young population.

The effect of c-Fos demethylation on sodium fluoride-induced apoptosis in L-02 cells

To investigate the effects of sodium fluoride (NaF) on apoptosis, c-Fos mRNA and protein expression levels, and methylation status as well as Dnmt1, Dnmt3a, and Dnmt3b mRNA expression levels in human embryo hepatocyte (L-02) which were exposed to different concentrations of NaF (0, 20, 40, and 80 mg/l) for 24 h in vitro. Results showed that the percentage of apoptosis and c-Fos mRNA and protein expression levels in 40 and 80 mg/l NaF-treated groups were higher than those in the control group (P<0.05). Further, Dnmt1 mRNA expression level was significantly decreased in the 80 mg/l NaF-treated groups compared to the control group (P<0.05); Dnmt3a and Dnmt3b mRNA expression levels were significantly decreased in 40 and 80 mg/l NaF-treated groups compared to the control group (P<0.05). c-Fos methylation levels, according to the bisulfite sequencing results, were decreased in 20, 40, and 80 mg/l NaF-treated groups against the control group. These results suggest that NaF could induce apoptosis and upregulate mRNA and protein expression level of c-Fos as well as decrease mRNA expression levels of Dnmt1, Dnmt3a, and Dnmt3b in L-02 cells. The decrease in c-Fos methylation levels might be involved in the early phase of apoptosis induced by NaF in L-02 cells.

Combined influence of intermittent exercise and temperature stress on the modulation of fluoride toxicity

Regardless of the circumstantial evidences on the involvement of fluoride on the etiology and pathogenesis of fluorosis, several lines of evidences strongly indicate the influence of modulator factors such as duration of fluoride exposure, age, temperature, and physical activity. This study has been designed to investigate the combined influence of intermittent exercise and temperature stress on the modulation of fluoride toxicity. Three-month-old Wistar male rats were exposed to high sodium fluoride (600 ppm) through drinking water for 1 month and the rats were then subjected to swimming exercise at different temperatures (20°C, 25°C, 30°C, and 35°C). Oxidative stress indices analyzed showed fluoride-induced oxidative stress in biological tissues studied like brain, heart, liver, and kidney. Exercise regimen coupled with different temperatures were found to be effective in bringing the oxidative stress indices to near normal level indicating decreased free radical production which may be a compensatory mechanism to counteract against the detrimental effects of fluoride. Further, the deleterious effects of fluoride significantly reduced at 25°C and 30°C demonstrating that the thermoneutral temperatures were effective in reducing the toxicity level.

Effectiveness of a mouthrinse containing active ingredients in addition to chlorhexidine and triclosan compared with chlorhexidine and triclosan rinses on plaque, gingivitis, supragingival calculus and extrinsic staining

OBJECTIVES

To assess the effectiveness of three different mouthrinses--chlorhexidine, triclosan + sodium fluoride and chlorhexidine + triclosan + sodium fluoride + zinc chloride--on plaque, calculus, gingivitis and stains and to evaluate the occurrence of adverse effects with these three treatments.

METHODS

Forty-eight healthy subjects participated in a double-blind, randomized, parallel experiment and were randomly allocated to any one of the three experimental mouthrinses: group A (0.2% chlorhexidine (CHX) gluconate), group B (0.03% triclosan + 0.025% sodium fluoride (NaF) + 12% ethyl alcohol) or group C (0.2% CHX + 0.3% triclosan + 0.3% NaF + 0.09% Zn chloride (ZnCl(2)). All the subjects were assessed for gingivitis, plaque, supragingival calculus and extrinsic stains at baseline and at the end of the 21-day experimental period.

RESULTS

There was a significant difference (P = 0.046) in the effectiveness for the prevention of gingivitis and plaque, with subjects of group A and group C presenting least and highest gingival and plaque scores, respectively. Significant differences (P = 0.03) were observed for the accumulation of supragingival calculus where the deposition of calculus in group A was nearly double that of the group B, and group B was most effective in the prevention of supragingival calculus. Highest deposition of extrinsic stains was in the group A followed by group C and group B. There was no significant difference between the three treatments for adverse events' occurrence.

CONCLUSIONS

CHX mouthrinse was most effective in controlling plaque and gingivitis but caused greatest deposition of extrinsic stains. Supragingival calculus deposition was least in triclosan + NaF group followed by CHX + triclosan + NaF + ZnCl(2) and CHX. More than half of the subjects reported adverse events during the experimental phase.

Effect of sodium fluoride and magnesium chloride on different hydroxyproline fractions in rat liver

Sodium fluoride (NaF) is used for prevention of caries in the form of fluoridated drinking water, fluoride tablets etc. In the present study, the effect of NaF-induced alterations in hydroxyproline (Hyp) and collagen was investigated in rat liver. The effect of pretreatment with MgCl2 on NaF-induced changes in liver Hyp and collagen was also studied. The NaF treatment at 5, 10 and 20 mg/kg body wt (reported LD50 of NaF being 24 mg/kg body wt through intraperitoneal route) caused a significant decrease in free Hyp (P < 0.05), when compared to control rats. The rats treated with 20 mg/kg body wt of NaF showed a significant increase in protein-bound Hyp (P < 0.001), as compared to control group, while of NaF treatment at 5 and 10 mg/kg body wt caused no significant change in protein-bound Hyp. All the doses of NaF had no significant effect on peptide-bound and total Hyp and total collagen. Treatment of with MgCl2 alone (30 mg/kg body wt) or with NaF (10 mg/kg body wt) caused a significant decrease in free Hyp (P < 0.05). MgCl2 alone and with NaF caused a significant increase (P < 0.05) in total collagen content. Thus, the present study demonstrated that NaF had no significant effect on total Hyp and collagen, indicating that its use in various products may not interfere with the liver collagen.

[Quality of life in cryolite production workers depending on length of service]

Federal budgetary establishment of a science "the Ekaterinburg medical centre of science of preventive maintenance and health protection of workers industrial plants". Findings are that adaptation level and life quality parameters progressively decrease with longer length of service. The most unfavorable parameters are seen in cryolite production workers with length of service over 20 years and in age group of 45-55 years. Conclusion is that treatment and prevention are necessary.

Intravenous ibandronate or sodium-fluoride--a 3.5 years study on bone density and fractures in Crohn's disease patients with osteoporosis

BACKGROUND AND AIM

Osteoporosis commonly afflicts Crohn's disease (CD) patients. Management remains unclear, with limited results for intravenous (i.v.) bisphosphonates and a follow-up longer than one year. Intravenous bisphosphonates bypass gastrointestinal-tract irritation offering an interesting alternative suitable for CD patients. We tested the long-term efficacy and safety of colecalciferol and calcium with sodium-fluoride or i.v. ibandronate for osteoporosis in CD.

METHODS

66 CD patients with lumbar osteoporosis (T-score<-2.5) were randomized to receive colecalciferol (1000 IU), calcium-citrate (800 mg) and intermittent sustained-release sodium-fluoride (50 mg) [groupA, n=33] or i.v. ibandronate (1 mg/3-monthly) [groupB, n=33]. Dual-energy X-ray absorptiometry of the lumbar-spine and right femur and X-rays of the spine were performed at baseline and after 1.0, 2.25 and 3.5 years. Fracture-assessment included visual reading and quantitative morphometry of X-rays.

RESULTS

55 (83.3%) patients completed at least the 1st year available for intention-to-treat (ITT) analysis, 42 (63.6%) completed the 2nd and 35 (53.0%) the 3rd year available for per-protocol analysis. Lumbar T-score increased by +0.23±0.43 (95%CI: 0.057-0.407, p<0.05), +0.71±1.05 (95%CI: 0.193-1.232, p<0.001) and +0.73±0.82 (95%CI: 0.340-1.336, p<0.001) (group A), and +0.28±0.41 (95%CI: 0.132-0.459, p<0.05), +0.43±0.55 (95%CI: 0.184-0.671, p<0.01) and +0.51±0.74 (95%CI: 0.145-0.882, p<0.001) (group B) during 1.0, 2.25 and 3.5 years follow-up time. In 2.71 years of follow-up, with the ITT analysis, the lumbar T-score increased by +0.66±0.97 (group A, p<0.001) and +0.46±0.67 (group B, p<0.001). One vertebral fracture with sodium-fluoride was not enough to detect differences between groups and the study was not powered for this. Study medication was well-tolerated and safe.

CONCLUSIONS

Sodium-fluoride and i.v. ibandronate improved osteoporosis. Keeping in mind bisphosphonates as a standard of osteoporosis care that reduce fracture-rate, data we do not have for sodium-fluoride, CD patients with osteoporosis can be treated safely with i.v. ibandronate.

Fluorine-induced apoptosis and lipid peroxidation in human hair follicles in vitro

Fluoride is an essential trace element for human body; however, exposure to high amounts of fluoride has been documented to be correlated with an increasing risk of hair loss. To date, little is known about the mechanism(s) of how fluoride affects hair follicles. Here, we demonstrated that middle (1.0 mmol/L) and high (10.0 mmol/L) concentrations of sodium fluoride (NaF) significantly inhibited hair follicle elongation in vitro, but low NaF (0.1 mmol/L) showed little influence. Moreover, treatment with high levels of NaF resulted in a marked increase in terminal dUTP nick end labeling-positive cells in the outer layer of the outer root sheath, the dermal sheath, and the lower bulb matrix surrounding dermal papilla. Furthermore, the enhanced apoptosis was coupled with an increased oxidative stress manifested as higher malondialdehyde content. Additionally, the presence of selenium considerably antagonized the effects of middle NaF on hair follicles, with regard to either the suppression of hair growth or the induction of oxidative stress and apoptosis. In conclusion, exposure to high levels of fluoride compromises hair follicle growth and accelerate cell apoptosis in vitro. The toxicity of fluoride can be reduced by selenium, at least partially via the suppression of intracellular oxidative stress.

Do active ingredients in non alcoholic chlorhexidine mouth wash provide added effectiveness? Observations from a randomized controlled trial

BACKGROUND AND OBJECTIVE

Chlorhexidine (CHX) is the most tested and leading oral antiseptic agent. Zinc as an active ingredient has shown additive and synergistic effect and when Sodium fluoride (NaF) was used it failed to show added effectiveness and the combined effect of NaF and Zinc chloride (ZnCl2) both as active ingredients has never been evaluated. The present study assessed the effectiveness of active ingredients and to compare the frequency of adverse events occurring with traditional CHX and CHX+NaF+ZnCl2.

MATERIAL AND METHODS

A randomized double blind crossover trial was executed with 24 subjects participating in two consecutive experimental phases of 21 days each with CHX and CHX+NaF+ZnCl2 mouth rinses. Each individual was assessed for gingivitis, plaque, supragingival calculus and extrinsic stains at baseline and after experimental phase and adverse events experienced were recorded.

RESULTS

There was a significant difference (p = 0.014) between the two experimental mouth rinses for their effectiveness on gingivitis. In the CHX group, the gingival score on D21 was significantly greater by 0.13 than DO while with CHX+NaF+ZnCl2 there was a decrease in gingival score by 0.09 which was insignificant. No significant difference was observed between the interventions for plaque accumulation and formation of extrinsic stains. The difference in the mean calculus score at baseline and after experimental phase was 1.47 for CHX+NaF+ZnCl2 in contrast to 1.93 among CHX group. Oral itching, oral soreness, apthous ulcers and dryness were reported by many subjects while burning sensation was reported by very few volunteers. There was no significant difference for occurrence of adverse events between the two experimental mouthrinses.

CONCLUSIONS

CHX+NaF+ZnCl2 mouth rinse was found to be significantly more effective in the reduction of gingivitis and supragingival calculus. No significant difference was found for the occurrence of dental plaque, extrinsic stains and adverse events between the interventions.

Influence of supplementary vitamins and minerals on lipid peroxidation and redox state in heart, kidney and liver of rats exposed to fluoride

The effect of fluoride (F) and supplementary vitamins and minerals on lipid peroxidation (LPO) and redox state (RS) in heart, kidney and liver of 40 (4 groups of 10) male Wistar rats were studied. One group of rats was left untreated as control, group 1 was received 5 mg/l NaF in their drinking water, group 2 was received 5 mg/l NaF in their drinking water plus vitamins (A, C, and D) in their diet, and group 3 was received 5 mg/l NaF in their drinking water plus vitamins (A, C, and D) and minerals (Mg-, Mn-, Zn-sulfate, and Na-citrate) in their diet. In comparison with the group 2, 3 and controls, elevated malondialdehyde (MDA) content in the group 1 indicated an increase in LPO product. In addition, unsteady ratios of oxidized to reduced nicotinamide adenine dinucleotide (NAD+/NADH) reflected significant alterations in the RS status. These results demonstrate that the combination of vitamins and minerals supplementation proved to restore MDA content and establish steady RS status that has not been previously reported.

Effect of boron as an antidote on dry matter intake, nutrient utilization and fluorine balance in buffalo (Bubalus bubalis) exposed to high fluoride ration

It is well known that excessive accumulation of fluorides can exert toxic effects on various tissues and organs so as to severely damage the health and production of animals. The aim of this study was to determine beneficial effect of boron on nutrient utilization in buffalo calves exposed to high fluoride (F) ration. For this purpose, we used three groups of four male Murrah buffalo calves (body weight 98-100 kg, aged 6-8 month) each. Control animal was given only basal diet and concentrate mixture. However, treatment I animals were fed basal diet, concentrate mixture, and F [as NaF, 60 ppm of dry matter (DM)]. The treatment II animals were fed basal diet, concentrate mixture, F (as NaF, 60 ppm of DM), and B (as sodium tetraborate, 140 ppm of DM). After 90 days of experimental feeding, a metabolism trial of 7 days duration was conducted to study the treatment effect on nutrient utilization of proximate nutrients, absorption, excretion, and retention of N, Ca, P, Fe, Zn, Cu, and F. Dietary F significantly (p < 0.05) depressed the dry matter intake and increased the apparent digestibility, absorption, and retention of F. However, boron supplementation significantly (p < 0.05) decreased the apparent digestibility, absorption, and retention of F and improved the dry matter intake, fecal excretion, and percent of absorbed F excreted via urine. Apparent digestibility of proximate nutrients (viz. DM, crude protein, crude fiber, ether extract, and nitrogen free extract) was unaffected on either F or F+B treatment. However, absorption and excretion of N, Ca, P, Fe, Zn, and Cu were affected significantly (p < 0.05) on F or F+B treatment. These findings suggest that fluoride-containing diet for short duration has effect on nutrient utilization, and boron at 140-ppm dose level, in general, antagonized the absorption and retention of F and also improved the feed intake in buffalo calves.

The effect of anti-sensitivity dentifrices on brushing abrasion of eroded dentin in vitro

OBJECTIVE

To investigate the abrasive effects of three marketed anti-sensitivity, and one marketed regular dentifrice on dentin, using an erosion-abrasion in vitro model.

METHODS

Standardized human dentin specimens were prepared and exposed to cycles of erosion, remineralization, and tooth brushing, utilizing the four commercially available dentifrices. Dentin surface loss was then measured by optical profilometry after a total of nine complete cycles. The RDA and pH values of the dentifrices were also measured to assist in the interpretation of results.

RESULTS

Profilometry showed significantly greater dentin surface loss for both Colgate Sensitive Fresh Stripe and Colgate Sensitive Multi Protection when compared with Sensodyne Total Protection or Crest Cavity Protection dentifrices. The abrasive level of dentifrices correlated positively (r-squared = 0.66; p < 0.05) with dentin surface loss.

CONCLUSION

This study demonstrated that the abrasivity of dentifrices can have a significant effect on the wear of eroded dentin in vitro.

Micromolar fluoride alters ameloblast lineage cells in vitro

Fluorosed enamel is caused by exposure to fluoride during tooth formation. The objective of this study was to determine whether epithelial ameloblast-lineage cells, derived from the human enamel organ, are directly affected by micromolar concentrations of fluoride. Cells were cultured in the presence of fluoride, and proliferation was measured by BrdU incorporation. The effect of 0, 10, or 20 microM fluoride on apoptosis was determined by the flow cytometry apoptotic index. The effects of fluoride on gene expression were investigated by SuperArray microarray analysis and real-time PCR. Fluoride had a biphasic effect on cell proliferation, with enhanced proliferation at 16 microM, and reduced proliferation at greater than 1 mM F. Flow cytometry showed that both 10 microM and 20 microM NaF significantly increased the apoptotic index of ameloblast-lineage cells. There was no general effect of fluoride on gene expression. These results indicate multiple effects of micromolar fluoride on ameloblast-lineage cells.

The Influence of Fluoride Varnish on the Attrition of Dentine

Previous investigations have shown the potential for fluoride to be protective in an abrasion/erosion laboratory model. The aim of this study was to investigate the effect of high concentrations of fluoride delivered in a varnish on attrition of dentine. Fifteen caries-free, intact lower third molar teeth were sectioned and the enamel removed by a water-cooled diamond disc. Polished dentine surfaces were divided into 8 areas, 4 of which were randomly covered with a high-concentration fluoride varnish for 24 h. The samples were subjected to 5,000 cycles of attrition bathed under artificial saliva. Microhardness testing adjacent to the wear scars showed no statistical difference between the fluoride-treated (71.42 KHN, SD 10.52) and control surfaces (72.66 KHN, SD 9.69). The volume of the wear scar was statistically greater for the fluoride-treated surface at 9.6 microm(3) (SD 4.92) and 8.13 microm(3) (SD 5.54) for the control areas (p = 0.029). The low pH of the fluoride varnish appears to have increased the amount of wear from attrition in this laboratory study.

Lack of DNA damage induced by fluoride on mouse lymphoma and human fibroblast cells by single cell gel (comet) assay

Fluoride has widely been used in Dentistry because it is a specific and effective caries prophylactic agent. However, excess fluoride may represent a hazard to human health, especially by causing injury on genetic apparatus. Genotoxicity tests constitute an important part of cancer research for risk assessment of potential carcinogens. In this study, the potential DNA damage associated with exposure to fluoride was assessed by the single cell gel (comet) assay in vitro. Mouse lymphoma and human fibroblast cells were exposed to sodium fluoride (NaF) at final concentration ranging from 7 to 100 microg/mL for 3 h at 37 degrees C. The results pointed out that NaF in all tested concentrations did not contribute to DNA damage as depicted by the mean tail moment and tail intensity for both cellular types assessed. These findings are clinically important because they represent a valuable contribution for evaluation of the potential health risk associated with exposure to agents usually used in dental practice.

Effects of systemic fluoride and in vitro fluoride treatment on enamel crystals

Systemically administered fluoride at a concentration of 75 ppm increases the surface roughness of developing enamel crystals in rats, which may be significant in advancing our understanding of the biological mechanism of fluorosis. Thus, the aim of this study was to investigate whether the increased surface roughness may be a result of surface restructuring by the direct action of fluoride at the crystal surface. We examined the fluoride dose-dependent roughening of enamel crystal surfaces in vivo, in the rat, and whether this roughening could be mimicked by the in vitro treatment of rat enamel crystals with neutral pH fluoride solutions. Our results showed that enamel crystal surface roughness increased after treatment with increasing fluoride ion concentrations, whether applied in vitro or administered systemically. This suggests a mechanism, alongside others, for the increased surface roughness of crystals in fluorotic enamel.

Allergic contact stomatitis from colophony

Colophony is an ubiquitous contact sensitizer which may be present in dental materials, such as periodontal dressings, impression materials, cements, fix adhesives and varnishes. Exposure to a sensitizer in a hypersensitive person may initiate an allergic contact dermatitis/stomatitis. This usually occurs after direct skin/mucosa contact with the sensitizer. This paper reports the case of a colophony hypersensitive male who developed contact stomatitis after dental treatment with a colophony-containing product.

CLINICAL RELEVANCE

Sensitizing colophony is present in Duraphat 2.26%F varnish, a fluoride varnish used all over the world. A case of hypersensitivity to Duraphat 2.26%F varnish is presented in a patient who, at the initial visit, indicated only an allergy to sticking plasters.

[Immunity and normal pharyngeal microflora in persons living in a technogenically exposed area]

The impact of industrial emissions of an aluminum plant of immunity and pharyngeal mucosal biocenosis were studied in healthy individuals living in the Sovetsky district. The effect of sodium fluoride in various concentrations on the activity of metabolic enzymes in the bacterial Staphylococcus epidermis cells isolated from the pharyngeal mucosa of the healthy individuals was also studied. The persons living in the Sovetsky district were found to have higher values of cellular immunity, an increase in the quantitative composition of the oral microflora being observed when its qualitative composition was worse. Various concentrations of sodium fluoride were ascertained to have a heterodirectional impact on microbial metabolism.

Remineralisation of carious enamel lesions after application of a CHX/F-mouthrinse compared with sole CHX- and placebo-application

PURPOSE

The purpose of this cross-over, double-blind, placebo-controlled, randomised in situ study was to evaluate the remineralisation of demineralised enamel specimens using a CHX/NaF mouthrinse in comparison with a CHX- and a placebo-mouthrinse.

MATERIALS AND METHODS

Twenty-four volunteers received intraoral appliances with mounted demineralised enamel specimens. They rinsed their mouths twice a day (10 ml for 1 minute) with the respective preparation. After 14 days, the in situ mineral gain and fluoride uptake were determined.

RESULTS

Mineral gain was significantly higher after using CHX/F mouthrinse (358.4 +/- 372.1 Vol.% X microm) compared with CHX (95.6+/-192.2 Vol.% X microm) and placebo treatment (80.8 +/- 159.6 Vol.% x microm). Moreover, CHX/F treatment (2751.1+/-1494.9 microg/cm(3)) resulted in a significantly higher fluoride uptake compared with CHX- (83.8+/-94.0 microg/cm(3)) and placebo- (136.6+/-137.3 microg/cm(3)) mouthrinses.

CONCLUSION

The in situ study approves that using a CHX/F mouthrinse supports the remineralisation of initial carious lesions.

In vitro evaluation of the efficacy and safety of the intelliclean system: interproximal biofilm removal and dentin substrate wear

The ability of a novel integrated power toothbrush and liquid-toothpaste dispensing system, the IntelliClean System from Sonicare and Crest, to remove interproximal biofilm while being gentle on dentin was studied using two in vitro models. Interproximal biofilm removal was assessed via a complex multispecies biofilm grown on hydroxyapatite disks and then placed interproximally in a typodont section modeling a typical oral environment. The power toothbrush in the prototype integrated system was compared to a traditional rotating/oscillating power toothbrush, the Oral-B ProfessionalCare 7000, and a nonbrushing control through a series of 3 experiments with a total of 36 replicates per arm. The amount of interproximal plaque biofilm removed by the integrated system toothbrush was significantly greater than that removed by the rotating/oscillating toothbrush and by the nonbrushing control (P < .05). In the second model, dentin substrate wear was measured using profilometry after the brushing of dentin sections (3 mm x 10 mm) for a period equivalent to 2 years of typical product use. Dentin wear associated with the use of the prototype integrated system with standard and whitening versions of the liquid toothpaste was compared to that of a rotating/oscillating power toothbrush and a manual toothbrush with the standard version of the prototype liquid toothpaste, with a total of 12 replicates per arm. The amount of dentin wear induced by the integrated system with either the standard or whitening liquid toothpaste was significantly less than the wear from the rotating/oscillating power toothbrush and the manual toothbrush with the standard liquid toothpaste (P < .05).

The Effect of Tamoxifen and Fluoride on Bone Mineral Density, Biomechanical Properties and Blood Lipids in Ovariectomized Rats

The most important aspect of therapy with fluoride and tamoxifen concerns its influence on bone tissue and lipid metabolism. The aim of the study was to evaluate the effect of tamoxifen and natrium fluoride (NaF) on bone metabolism, biochemical properties and blood lipids levels in ovariectomized rats. The study was performed in Wistar rats divided into 5 subgroups: ovariectomized controls, rats treated with NaF 20 mg/kg/24 hr, rats treated with NaF 20 mg/kg/24 hr+tamoxifen 2 mg/kg/24 hr, rats treated with NaF 20 mg/kg/24 hr plus tamoxifen 4 mg/kg/24 hr, and sham-operated controls. In ovariectomized rats the increase of total cholesterol, low-density lipoproteins cholesterol (LDL-cholesterol) as well as the decrease of bone mineral content, bone mineral density and biomechanical properties was observed. The therapy with NaF increased the level of total cholesterol, LDL-cholesterol, triglycerides, bone mineral density, bone mineral content. In this group the decrease of bone strength and stiffness was observed. The administration of tamoxifen reduced the changes in plasma lipid levels, but did not improve the biomechanical properties of bone tissue.

Effect of 0.02% NaF solution on enamel demineralization and fluoride uptake by deciduous teeth in vitro

The application of 0.02% NaF solution on teeth with a cotton swab instead of brushing with fluoride dentifrice has been suggested for young children to reduce the risk of dental fluorosis, but its anticariogenic effect has not been evaluated. Thus, we studied the in vitro effect of 0.02% NaF solution on enamel demineralization and fluoride uptake in deciduous teeth; non-fluoride dentifrice and fluoride dentifrice (1,100 mg F/g) were used, respectively, as negative and positive controls. The treatment with fluoride dentifrice was more effective in reducing enamel demineralization (p < 0.05) and on fluoride uptake by the enamel (p < 0.05) than the non-fluoride dentifrice and the 0.02% NaF solution. Data suggest that the alternative use of 0.02% NaF solution instead of fluoride dentifrice should be reevaluated especially if dental caries are to be controlled.

Three-year effectiveness of intravenous pamidronate versus pamidronate plus slow-release sodium fluoride for postmenopausal osteoporosis

All currently available and approved therapies for osteoporosis inhibit bone resorption. But, despite their great value, antiresorptive agents are generally not associated with dramatic increases in bone mass. In light of these data, the aim of our prospective, placebo-controlled, randomized clinical trial, with a 3-year follow up, was to examine the effects of cyclic intravenous pamidronate and fluoride in combination, versus pamidronate alone, on bone mineral density (BMD) at vertebral and femoral levels, biochemical markers of bone turnover, IGF-1 serum levels, and safety and tolerability in 40 postmenopausal women with osteoporosis. During the treatment period, pamidronate alone reduced both markers of bone formation and bone resorption, resulting in an increase of BMD, after 3 years, of 7.07% at the lumbar level and of 6.76% at the femoral level. In the group treated with pamidronate and fluoride, markers of bone turnover had a different trend: after 3 years, there was a lower reduction of bone resorption and an increase of bone formation markers, with a concomitant increase in IGF-1 levels. This resulted, after 3 years of treatment, in a marked variation of BMD at the lumbar level (+12.74%) and a reduced, but still significant, increase at the femoral level (3.89%). Spine radiography and clinical evaluation did not reveal any vertebral fractures in either treatment group. In conclusion, the combined use of pamidronate and fluoride produced somewhat larger, continuous increases in BMD, at the lumbar level, than pamidronate alone.

[Phenomenon of pseudomutagenesis: experiments with modifiers of cell metabolism in human lymphocytes]

The term "pseudomutagens" is suggested for factors that increase the spontaneous mutation level not by induction of DNA molecule changes but as a result of inhibition of the repair of spontaneous pre-mutation lesions. The expected regularities of pseudomutagen effects, which are suitable as criteria for their identification, are considered. The experimental results on the effects of six modifiers of cell metabolism in human lymphocytes are analyzed. Four of the modifiers (5-fluorodeoxyuridine, sodium cyanide, sodium fluoride and monoiodoacetic acid) behaved as pseudomutagens according to all the criteria applied. 2,4-Dinitrophenol proved to be a true mutagen. Adenosine diphosphate revealed unusual properties: it inhibited the repair of spontaneous lesions but decreased the frequency of structural mutations induced by radiation. The significance of the phenomenon of the pseudomutagenesis for the problem of environmental mutagens/carcinogens is discussed.

Hypocalcaemia in parental and F1 generation rats treated with sodium fluoride

The potential of sodium fluoride (NaF) to affect serum cations was assessed in the parent (P) and F1 generation rats. The sperm-positive pregnant experimental female rats received 40 mg NaF/kg body weight from day 6 of gestation either up to 21 days of lactation or only up to gestation followed by withdrawal of the treatment during lactation. On day 21 of lactation, blood samples were collected from P and F1 generation rats, allowed to clot and centrifuged at 1000 g for 10 min to obtain serum for analysis of various cations. Statistically significant increases in the concentrations of sodium and potassium in the serum of P and F1 generation rats were observed in the NaF-treated group; however, calcium and phosphorus concentrations were significantly lower than their vehicle control. Withdrawal of NaF treatment during lactation caused significant recovery in sodium, potassium and phosphorus concentrations in P and F1 generation rats as compared with NaF-treated animals. Although statistically significant recovery was not observed, the calcium concentration in P and F1 generation rats was comparatively higher on withdrawal of NaF treatment than in the NaF-treated group. It is concluded that the exposure of 40 mg NaF/kg body weight in pregnant female rats caused significant alterations in cationic concentration which recovered significantly (except calcium) on withdrawal of the treatment.

Comparative intraoral tolerance of sodium hexametaphosphate and pyrophosphate antitartar dentifrices

A randomized, controlled clinical trial was conducted to assess the relative acute oral tolerance of a novel, dual-phase, tartar control dentifrice containing 7.0% sodium hexametaphosphate (5% hexametaphosphate anion). In this 4-day study, 159 healthy adult volunteers were randomly assigned to the experimental sodium hexametaphosphate dentifrice or a marketed, single-phase, antitartar dentifrice control containing 5.0% ionic pyrophosphate. A detailed oral soft tissue examination and interview were conducted each day by blinded evaluators to elicit clinical signs and symptoms associated with ad libitum use of the assigned dentifrice. A total of 24 subjects (15% of the study population) had new symptoms/signs after baseline. By treatment, 9% of subjects in the sodium hexametaphosphate group had new findings, compared to 21% of subjects in the pyrophosphate group, and these groups differed statistically (p < 0.03, two-sided) with respect to occurrence. In addition, onset, severity, duration and clinical presentation were generally milder in the sodium hexametaphosphate group compared to the pyrophosphate control. Only one subject (in the pyrophosphate group) discontinued treatment early due to oral intolerance. In this study, the 7.0% sodium hexametaphosphate dentifrice was well-tolerated, with significantly fewer symptoms and superior overall tolerance compared to the marketed antitartar dentifrice control.

A randomized trial of sodium fluoride (60 mg) +/- estrogen in postmenopausal osteoporotic vertebral fractures: increased vertebral fractures and peripheral bone loss with sodium fluoride; concurrent estrogen prevents peripheral loss, but not vertebral fractures

Postmenopausal Caucasian women aged less than 80 years (n = 99) with one or more atraumatic vertebral fracture and no hip fractures, were treated by cyclical administration of enteric coated sodium fluoride (NaF) or no NaF for 27 months, with precautions to prevent excessive stimulation of bone turnover. In the first study 65 women, unexposed to estrogen (-E study), age 70.8 +/- 0.8 years (mean +/- SEM) were all treated with calcium (Ca) 1.0-1.2 g daily and ergocalciferol (D) 0.25 mg per 25 kg once weekly and were randomly assigned to cyclical NaF (6 months on, 3 months off, initial dose 60 mg/day; group F CaD, n = 34) or no NaF (group CaD, n = 31). In the second study 34 patients, age 65.5 +/- 1.2 years, on hormone replacement therapy (E) at baseline, had this standardized, and were all treated with Ca and D and similarly randomized (FE CaD, n = 17; E CaD, n = 17) (+E study). The patients were stratified according to E status and subsequently assigned randomly to +/- NaF. Seventy-five patients completed the trial. Both groups treated with NaF showed an increase in lumbar spinal density (by DXA) above baseline by 27 months: FE CaD + 16.2% and F CaD +9.3% (both p = 0.0001). In neither group CaD nor E CaD did lumbar spinal density increase. Peripheral bone loss occurred at most sites in the F CaD group at 27 months: tibia/fibula shaft -7.3% (p = 0.005); femoral shaft -7.1% (p = 0.004); distal forearm -4.0% (p=0.004); total hip -4.1% (p = 0.003); and femoral neck -3.5% (p = 0.006). No significant loss occurred in group FE CaD. Differences between the two NaF groups were greatest at the total hip at 27 months but were not significant [p < 0.05; in view of the multiple bone mineral density (BMD) sites, an alpha of 0.01 was employed to denote significance in BMD changes throughout this paper]. Using Cox's proportional hazards model, in the -E study there were significantly more patients with first fresh vertebral fractures in those treated with NaF than in those not so treated (RR = 24.2, p = 0.008, 95% CI 2.3-255). Patients developing first fresh fractures in the first 9 months were markedly different between groups: -23% of F CaD, 0 of CaD, 29% of FE CaD and 0 of E CaD. The incidence of incomplete (stress) fractures was similar in the two NaF-treated groups. Complete nonvertebral fractures did not occur in the two +E groups; there were no differences between groups F CaD and CaD. Baseline BMD (spine and femoral neck) was related to incident vertebral fractures in the control groups (no NaF), but not in the two NaF groups. Our results and a literature review indicate that fluoride salts, if used, should be at low dosage, with pretreatment and co-treatment with a bone resorption inhibitor.

The relation between toothpaste usage and fluorosis: a cause for concern?

Fluoride-containing toothpaste is by far the most widespread source of fluoride in the world and after fluoridated water the most cost-effective at reducing dental caries. Of the seven current issues in the development of fluoride-containing toothpaste described by Holt & Murray (1997), five are either directly or indirectly related to the risk of developing fluorosis, a phenomenon which is on the increase in the industrialised world. The purpose of this study was to evaluate fluoride-containing toothpaste available to the South African public regarding the issues described by Holt & Murray (1997) and to relate the results to the possible development of fluorosis. The amount of fluoride ingested from toothpaste was calculated using the total fluoride concentration present in toothpaste, quantity of toothpaste used per brushing, mean percentage of toothpaste ingested and the 90th percentile of body weight. Results indicate that the "threshold" level of fluoride intake of 0.05 to 0.07 mg F/kg body weight/day beyond which dental fluorosis might occur (Burt, 1992), is exceeded when a ribbon of toothpaste was placed on a child's toothbrush at ages 2-3 years. 'Threshold' levels were ingested when placing a ribbon of toothpaste on the brush at ages 4 and 5 for all toothpaste as well as for a children's formulation containing 1000 microg F/g. Of all pastes studied, 41.9% of the packaging has information for the prevention of swallowing of paste and/or the supervision of children by adults when brushing. The dental profession, manufacturers of toothpaste and government all have a role to play in the prevention of fluorosis in the toothbrushing population of South Africa.

[Influence of free radical inducer on the level of oxidative stress in brain of rats with fluorosis]

OBJECTIVE

To study changes in content of lipid peroxide and composition of fatty acids in the brain of rats affiliated with chronic fluorosis after treatment with free radical inducer (ferric ion).

METHODS

Thirty-six Wistar rats were divided into three groups, fed with similar fodder and varied concentrations of fluoride in drinking water, and were killed five months after treatment. Lipid peroxidation was induced by ferric ions. Malondialdehyde content in brain was analysed by high-performance liquid chromatography; oxygen consumption was determined with an oxygen electrode and fatty acid composition was measured by gas chromatography in brain tissues of the rats.

RESULTS

In the brain tissues, content of malondialdehyde and oxygen consumption increased, composition of polyunsaturated fatty acids decreased and that of saturated fatty acids decreased after treatment with free radical inducer in the treated group, as compared with those in control group.

CONCLUSION

Over uptake of fluoride for a long term could cause potential increase in the level of oxidative stress in the brain tissue.

Dental hygienist and patient comparisons of fluoride varnishes to fluoride gels

PURPOSE

The purpose of this study was to evaluate a fluoride varnish and compare it to fluoride gels in categories including taste, comfort, efficiency, discoloration, moisture control, safety, and ease of application.

METHODS

Methods. Twenty-five licensed dental hygienists and 148 patients completed questionnaires comparing fluoride varnish to fluoride gel for the following categories: taste, comfort, efficiency, discoloration, moisture control, and safety. Responses were analyzed using descriptive statistics and a chi-square test.

RESULTS

The 25 dental hygienists rated fluoride varnish (Duraphat) superior to fluoride gels in all categories. Eighty-three (56.5%) of the 148 patients reported the varnish application to be more comfortable than gel while 29 (20%) found it the same. In taste comparison, 90 (71.4%) preferred the varnish, while 16 (12.7%) rated it the same. The time required was reported as better for the varnish technique by 59 (50.4%) and equal to the gels by 32 (20.3%). Discoloration of the teeth by the varnish was found not noticeable or not objectionable by 66 (49.3%) and somewhat objectionable or too noticeable for comfort in public by 68 (50.7%). However, 85 (64.3%) reported that they would choose to have the varnish treatment while 33 (25%) would not. Dental hygienist responses on questions 1-4 relative to the number of years in practice were not found to be significantly different.

CONCLUSION

The patients and dental hygienists in this study preferred fluoride varnishes to gels. However, since some patients objected to the temporary discoloration, varnishes may not be suitable for everyone.

The role of fluoride in the prevention of osteoporosis

Osteoporosis defined as low bone mass and increased susceptibility to fracture is a reflection of the sum of peak bone mass and any bone that has been lost once peak mass has been attained. Several strategies have been applied to optimize peak bone mass and to prevent bone loss. Fluoride has greatest potential as a therapy for osteoporosis once bone has been lost. It has been demonstrated both experimentally and clinically to stimulate bone formation directly and to increase bone mass in patients who already have osteoporosis. Several bone formation/stimulation therapies are under development, and some of these have reached the stage of clinical trial. None of these therapies has been as extensively studied as fluoride, and none is sufficiently advanced in development to be clinically available in the next 3 to 5 years. Fluoride therapy for osteoporosis is already performed in many countries, and approval for use in osteoporosis in the United States is pending. The first clinical trials of NaF therapy for osteoporosis were reported by Rich and Ensinck in 1961. Since then, hundreds of reports on the successes and failures of fluoride therapy have appeared in the literature. At first glance, it seems disappointing and inexplicable that, after 40 years of research, fluoride is still considered an experimental drug in the United States. One plausible explanation is that much of the early research on this drug was suboptimal, including the author's contributions. Fluoride as a naturally occurring element is difficult to patent, and this has kept major pharmaceutical companies from investing heavily in fluoride therapy despite its obvious potential. As a result, pharmacologic and pharmacokinetics studies of fluoride are limited in scope, as are phase I and phase II human toxicology and dose-finding studies. Most early studies of large doses of plain NaF were unable to demonstrate a consistent effect on fracture rate despite a consistent and dramatic effect on bone density. Once this became obvious and as new technologies for measuring bone density became available, it became equally clear that future clinical trials would have to be performed using different formulations of fluoride and lower doses. This approach has not resulted in uniformly positive clinical trials, and one must look elsewhere for answers. The most compelling explanation is that the trials have included patients with different severity of disease, suggesting that there is point in the bone loss spectrum at which even a potent bone-stimulating agent such as fluoride is ineffective. This possibility should provoke a reappraisal of the earlier negative studies: was the failure a result of the drug or of patient selection? The answer to this question is crucial, because these failures have cast a long shadow over the safety of fluoride and are contributing more to the absence of this drug from the pharmacopoeia than any other factor.

Acute fluoride toxicity from ingesting home-use dental products in children, birth to 6 years of age

OBJECTIVE

This paper analyzes reports to the American Association of Poison Control Centers (AAPCC) of suspected overingestion of fluoride by children younger than 6 years of age between 1989 and 1994, and estimates the probably toxic amounts of various home-use fluoride products in children younger than 6 years of age.

METHODS

Annual incidence rates of reported fluoride exposures attributed to dietary supplements, toothpaste, and rinses were calculated. Probably toxic amounts of each product were calculated using the frequently cited dose of 5 mg/kg.

RESULTS

Children younger than 6 years of age accounted for more than 80 percent of reports of suspected overingestion. While the outcomes were generally not serious, several hundred children were treated at health care facilities each year. A 10 kg child who ingests 50 mg fluoride (10.1 g 1.1% NaF gel; 32.7 g 0.63% SnF2 gel; 33.3 g 1,500 ppm F toothpaste; 50 g 1,000 ppm F toothpaste; and 221 mL 0.05% NaF rinse) will have ingested a probably toxic dose.

CONCLUSIONS

Overingestion of fluoride products in the home is preventable. Dentists and other health care providers should educate parents and child care providers about the importance of keeping fluoride products out of reach of children. Manufacturers should be encouraged by the ADA and the FDA to use child-resistant packaging for all fluoride products intended for use in the home.

Fluoride therapy in prevention of rheumatoid arthritis induced bone loss

OBJECTIVE

To determine the efficacy of sodium fluoride (40 mg/day) in preventing rheumatoid arthritis (RA) induced bone loss, which may lead to osteoporosis.

METHODS

We conducted an 18 month, randomized, double blind, placebo controlled trial in 38 patients with RA. The primary outcome measure was the difference in the percentage change between groups in lumbar spine bone mineral density (BMD) from baseline values after 18 months of therapy. The secondary outcome measures were the differences in the percentage change between groups in femoral neck, Ward's triangle, trochanter, and total body BMD from baseline after 18 months of therapy.

RESULTS

There was a significant percentage difference (SD) between groups of 6.2% (7.3%) (p = 0.0005) in lumbar spine BMD after 18 months of treatment in favor of the fluoride group. The fluoride group experienced a 5.2% (8.4%) (p = 0.0125) increase, whereas the placebo group showed a 1.0% (4.8%) (p = 0.8015) decrease in lumbar spine BMD after treatment. No significant differences were found for the femoral neck, Ward's triangle, trochanter, and total body BMD in terms of the percentage changes from baseline within each treatment group or in the differences in the degree of change between groups after therapy. Lumbar spine BMD increased in about 80% of patients treated with fluoride (responders) compared to 44% of patients treated with placebo.

CONCLUSION

The results showed that fluoride therapy was well tolerated and increased vertebral bone mass in patients with RA.