Salivary Fluoride Concentrations and Fluoride Ingestion Following Application of Preparations Containing High Concentration of Fluoride

The aim of the study was to assess salivary fluoride concentrations and ingestion of fluorides after five different techniques of topical fluoride treatment. Ten volunteers received applications of fluoride gel, toothpaste, and foam. Fluoride concentrations were determined using ion-selective fluoride electrode in the samples of unstimulated saliva before and after procedures. The amounts of fluoride applied, recovered from the mouth, and retained in the mouth were calculated for each treatment. It was proved that fluoride ingestion following tray application of fluoride foam was significantly lower than ingestion following tray applications of fluoride gel (p < 0.01). The use of limited amounts of fluorides on a tray resulted in similar fluoride retention and lower ingestion comparing to the method which involves a large portion of fluorides followed by rinsing. Tooth brushing resulted in high salivary retention rates per amount of fluorides used in the procedure. These data provide initial concept about the possible advantages of some methods of topical fluoride application over others.     

Urinary Fluoride Reference Values Determined by a Fluoride Ion Selective Electrode

As fluoride has a very short half-life in the body and the major route for fluoride excretion is via the kidney, human exposure is best measured in urine, where the concentration is expected to be highest. The urinary fluoride concentrations of 167 healthy Japanese adults were determined by means of a fluoride ion selective electrode. When the results were corrected for a specific gravity ρ = 1.024 g cm⁻³, the histogram of urinary fluoride concentrations highly skewed toward low values with sharp peakedness (skewness = 1.56, kurtosis = 3.08). The normality of the log-transformed histogram (skewness = 0.12, kurtosis = 0.07) and the straight line on log-probability paper clearly showed a key feature of lognormal distribution of urinary fluoride. A geometric mean (GM) of 613.8 μg/l and 95% confidential interval (CI) of 241.0–1633.1 μg/l were established as reference values for urinary fluoride. The results presented in this study will be useful as guidelines for the biological monitoring of fluoride in normal subjects and individuals at risk of occupational or environmental fluoride exposure.     

Influence of Methionine and Vitamin E on Fluoride Concentration in Bones and Teeth of Rats Exposed to Sodium Fluoride in Drinking Water

Increased exposure to fluorine-containing compounds leads to accumulation of fluorides in hard tissues of bones and teeth, which may result in numerous skeletal and dental disorders. This study evaluates the influence of methionine and vitamin E on fluoride concentration in bones and teeth of rats subjected to long-term exposure to sodium fluoride in drinking water. The study was conducted in 30 3-month-old female Wistar FL rats. The animals were divided into five groups, six rats per group. The control group consisted of rats receiving only distilled water as drinking water. All other groups received NaF in the amount of 10 mg/kg of body mass/day in their drinking water. In addition, respective animal groups received: NaF + Met group—10 mg of methionine/kg of body mass/day, NaF + Met + E group—10 mg of methionine/kg of body mass/day and 3 mg of vitamin E (tocopheroli acetas)/rat/day and NaF + E group—3 mg of vitamin E/rat/day. Femoral bones and incisor teeth were collected for the study, and the fluoride concentration was determined using a fluoride ion-selective electrode. Fluoride concentration in both bones and teeth was found to be higher in the NaF and NaF + Met groups compared to the control group. In groups NaF + Met + E and NaF + E, the study material contained much lower fluoride concentration compared to the NaF group, while the effect was more prominent in the NaF + E group. The results of the studies indicate that methionine and vitamin E have opposite effects on accumulation of fluorides in hard tissue in rats. By stimulating fluoride accumulation, methionine reduces the adverse effect of fluorides on soft tissue, while vitamin E, which prevents excessive accumulation of fluorides in bones and teeth, protects these tissues from fluorosis. Therefore, it seems that combined application of both compounds would be optimal for the prevention of the adverse effects of chronic fluoride intoxication.     

Fluoride exposure and factors affecting dental caries in preschool children living in two areas with different natural levels of fluorides

BackgroundSuccessful oral health interventions must be based on the specific needs of the population that they serve. Evaluation of habits related to dental caries development and estimation of fluoride exposure in a target group of young patients helps to plan effective and safe caries prevention strategies.ObjectivesThe study aimed to evaluate factors affecting dental caries experience and sources of fluoride exposure in preschool children living in two areas: with optimal and low natural content of fluoride in drinking water.Materials and methodsThe study included a group of 73 children of both sexes aged 4–7 years attending two kindergartens in Środa Wielkopolska and Turek (Wielkopolska Voivodeship, Poland), where the content of fluoride in drinking water according to data obtained in the sanitary station ranged from 0.68 to 0.74 mg/L (optimal concentration of fluoride) and from 0.19 to 0.30 mg/L (low concentration of fluoride), respectively. Parents of patients completed a survey about diet, hygiene, and dental care, taking into account the child's fluoride exposure. The calibrated dentist assessed the oral health condition using a mirror, a CPI probe, and a headlamp. Oral hygiene was recorded using the Silness and Löe plaque index, caries experience by calculating the numbers of decayed, missing, and filled primary, and permanent teeth (dmf and DMF, respectively) while caries frequency by calculating the percentage of children with caries experience above 0. In order to assess the fluoride concentrations in urine and drinking water, parents were asked to provide a urine sample collected on fasting and a tap water sample. Fluoride concentrations were assessed using a 09–37 (MARAT) fluoride ion-selective electrode and a RAE 111 silver-chloride reference electrode. Statistical analysis was conducted using the data analysis software system Statistica (version 12, StatSoft, Inc. 2014), assuming a statistical significance level p < 0.05.ResultsNo statistically significant differences were found between caries indices of the examined children in each kindergarten (p > 0.05). Urinary fluoride levels were higher in children who tended to swallow toothpaste or used fluoride rinses and positively correlated with fluoride concentrations in the drinking water. Dental caries experience in the examined children depended on the effectiveness and frequency of oral hygiene procedures and dietary habits.ConclusionsThe strategy aimed at improving the oral health of the examined group of children should include accomplishing oral hygiene, promoting a non-cariogenic diet, and, finally, controlling fluoride exposure from at-home fluoride products. Caries prevention program ought to be adjusted to individual characteristics of each child, taking into consideration oral hygiene practices, dietary habits and total fluoride intake.     

Serum and urine ionic fluoride

The present study was undertaken to evaluate the fluoride status in the general healthy population of Barcelona. Serum and urine fluoride ionic concentration was determined in a random sample of 250 subjects (age range 15–90 yr) by the Orion fluoride electrode system to determine the normal range of fluoride in this population. The results obtained show that in the general population of Barcelona, fluoride ionic serum concentration ranges between 1 and 47 μg/L (x = 17.5 ± 9.7 μg/L) and fluoride ionic urine concentration ranges between 156 and 1990 μg/24 h (x = 671 ± 373 μg/24 h). The mean serum fluoride concentration of the younger population was shown to be significantly greater (p < 0.05) than that of the older group. No sex-related difference was found.     

Alterations in Electrocardiographic Parameters after Subacute Exposure of Fluoride and Ameliorative Action of Aluminium Sulphate in Goats

Fluorosis or crippling disease is one of the existing environmental challenges for animal and human beings in most parts of the globe. In the present study, sodium fluoride alone and with aluminium sulphate (ameliorative agent) was administered orally daily for 30 days in healthy goats of group 1 and 2, respectively, to access the effect on the electrocardiogram. All waves of Lead I, Lead II, Lead III, aVR, aVL and aVF in electrocardiographs were recorded before and after 30 days exposure of fluoride. A significant (P < 0.05) increase in P–R, Q–T and S–T intervals were observed in goats of group 1 as compared to their pre treatment values. The T wave duration was also significantly (P < 0.05) prolonged and as a result, bradycardia was observed after subacute exposure of fluoride for 30 days in group 1. But, in group 2, no such changes were observed. On the basis of results, it may be concluded that subacute toxicity of fluoride produces significant changes in different waves of electrocardiogram and aluminium sulphate has ameliorative efficacy.     

Effects of Fluoride on Synaptic Membrane Fluidity and PSD-95 Expression Level in Rat Hippocampus

The objective of this study is to investigate the neurotoxicity of drinking water fluorosis on rat hippocampus. Just weaning male Sprague–Dawley rats were randomly divided into four groups and given 15, 30, and 60 mg/L NaF solution and distilled water, respectively, for 9 months. The fluidity of brain synaptic membrane and expression level of postsynaptic density 95 (PSD-95) were tested. Results showed that the fluidity of brain synaptic membrane decreased gradually with increasing of fluoride concentration, and it was significantly decreased (P < 0.05) in moderate-fluoride group compared with control group, and expression level of PSD-95 was significantly decreased (P < 0.01) in moderate-fluoride group when compared with that of control group. These results indicate that decrease of synaptic membrane fluidity and PSD-95 expression level may be the molecular basis of central nervous system damage caused by fluoride intoxication; PSD-95 in CA3 region of hippocampus is probably a target molecule for fluoride.     

Chronic Fluoride Exposure Has a Role in Etiology of Coronary Artery Ectasia: Sialic Acid/Glycosaminoglycan Ratio

The sialic acid/glycosaminoglycan ratio was determined in 35 coronary artery ectasia patients and 35 control subjects to determine the possible role of fluoride in the etiology of the disease. The coronary artery ectasia patients and controls were selected from subjects who underwent coronary angiography. The mean serum sialic acid level was significantly lower in patients with coronary artery ectasia (CAE) than in controls (340.3 ± 28.6 vs. 427.0 ± 15.9 μg/mL, respectively; p < 0.001). The mean serum glycosaminoglycan level was significantly higher in patients with CAE than in controls (5,013.1 ± 158.6 vs. 3,833.6 ± 237.1 μg/mL, respectively; p < 0.001). The sialic acid/glycosaminoglycan ratio in patients with coronary artery ectasia was significantly lower than in controls (0.068 ± 0.007 vs. 0.111 ± 0.005; p < 0.001). There was more than 38.7% reduction in this ratio in patients with CAE when compared with controls. We demonstrated that chronic fluoride exposure has an important role in pathogenesis of coronary artery ectasia.     

Analysis of Oral Microbiota in Children with Dental Caries by PCR-DGGE and Barcoded Pyrosequencing

Oral microbiota plays a vital role in maintaining the homeostasis of oral cavity. Dental caries are among the most common oral diseases in children and pathogenic bacteria contribute to the development of the disease. However, the overall structure of bacterial communities in the oral cavity from children with dental caries has not been explored deeply heretofore. We used high-throughput barcoded pyrosequencing and PCR-denaturing gradient gel electrophoresis (DGGE) to examine bacterial diversity of oral microbiota in saliva and supragingival plaques from 60 children aged 3 to 6 years old with and without dental caries from China. The multiplex barcoded pyrosequencing was performed in a single run, with multiple samples tagged uniquely by multiplex identifiers. As PCR-DGGE analysis is a conventional molecular ecological approach, this analysis was also performed on the same samples and the results of both approaches were compared. A total of 186,787 high-quality sequences were obtained for evaluating bacterial diversity and 41,905 unique sequences represented all phylotypes. We found that the oral microbiota in children was far more diverse than previous studies reported, and more than 200 genera belonging to ten phyla were found in the oral cavity. The phylotypes in saliva and supragingival plaques were significantly different and could be divided into two distinct clusters (p < 0.05). The bacterial diversity in oral microbiome analyzed by PCR-DGGE and barcoded pyrosequencing was employed to cross validate the data sets. The genera of Streptococcus, Veillonella, Actinomyces, Granulicatella, Leptotrichia, and Thiomonas in plaques were significantly associated with dental caries (p < 0.05). The results showed that there was no one specific pathogen but rather pathogenic populations in plaque that significantly correlated with dental caries. The enormous diversity of oral microbiota allowed for a better understanding of oral microecosystem, and these pathogenic populations in plaque provide new insights into the etiology of dental caries and suggest new targets for interventions of the disease.     

Elevation of PTH and PTHrp Induced by Excessive Fluoride in Rats on a Calcium-deficient Diet

Study on the role of parathyroid hormone (PTH) and parathyroid hormone-related peptide (PTHrp) in the process of skeletal fluorosis, involved especially in calcium deficiency, is rare. We evaluated the level of serum PTH and mRNA expression of PTHrp in femur when rats were exposed to excessive fluoride with low-calcium diet. Wistar rats (n = 60) was divided into four groups, a control group, fluoride group, low-calcium group, and low-calcium fluoride group. The fluoride groups were treated with fluoride by drinking tap water containing 100 mg F-/L. The low-calcium diet contained 0.05% calcium. Serum was collected in the first, fourth, eighth, and 12th of phase for the detemination of PTH and Ca²⁺. RNA extraction from femora was used to analyze the mRNA express of PTHrp, osteopontin (OPN), and osteocalcin (OCN) after 12 weeks of fluoride dosing. Results showed that serum PTH increased gradually with the extension of fluoride exposure, but Ca²⁺ decreased, both of which embodied a time-dependent relationship. Cotreatment of excessive fluoride with low-calcium diet largely stimulated the secretion of PTH. The low dietary calcium markedly increased mRNA expression of PTHrp in animals with fluoride treatment. Expression of OPN and OCN significantly increased in the rats treated with excessive fluoride and low-calcium diet. We demonstrated that fluoride by itself affected the body's calcium metabolism and stimulate the secretion of PTH. PTH may play an important role in anabolic effect of excessive fluoride on bone turnover of skeletal fluorosis and calcium deficiency exacerbated the action of PTH and PTHrp on the characteristic bone lesion of fluorosis.     

Fluoride and environmental health: a review

The relationship between environmental fluoride and human health has been studied for over 100 years by researchers from a wide variety of disciplines. Most scientists believe that small amounts of fluoride in the diet can help prevent dental caries and strengthen bones, but there are a number of adverse affects that chronic ingestion at high doses can have on human health, including dental fluorosis, skeletal fluorosis, increased rates of bone fractures, decreased birth rates, increased rates of urolithiasis (kidney stones), impaired thyroid function, and lower intelligence in children. Chronic occupational exposure to fluoride dust and gas is associated with higher rates of bladder cancer and variety of respiratory ailments. Acute fluoride toxicity and even death from the ingestion of sodium fluoride pesticides and dental products have also been reported. The distribution of fluoride in the natural environment is very uneven, largely a result of the geochemical behavior of this element. Fluorine is preferentially enriched in highly evolved magmas and hydrothermal solutions, which explains why high concentrations are often found in syenites, granitoid plutonic rocks, alkaline volcanic, and hydrothermal deposits. Fluoride can also occur in sedimentary formations that contain fluoride-bearing minerals derived from the parent rock, fluoride-rich clays, or fluorapatite. Dissolved fluoride levels are usually controlled by the solubility of fluorite (CaF₂); thus, high concentrations are often associated with soft, alkaline, and calcium-deficient waters. Although much is known about the occurrence and health effects of fluoride, problems persist in Third World countries, where populations have little choice in the source of their drinking water and food. However, even in developed nations, fluoride ingestion can exceed the recommended dose when sources other than drinking water are ignored.     

不同剂量的多乐氟对学龄前儿童尿氟浓度的影响

目的:观察儿童使用不同剂量的多乐氟氟化钠护齿剂(Duraphat)对其尿氟浓度的影响,为Duraphat应用于群防群治提供理论依据。方法:采用氟离子选择电极法,将53名3~4岁儿童按班别分成三组,分别使用0.2 m L及0.05 m L Duraphat涂布儿童牙齿,检测涂氟前和涂氟后1、2、3 d的尿氟浓度,并进行组内和组间比较。结果:各组使用Duraphat后尿氟浓度逐渐增加,涂氟后2 h开始与涂氟前比较差异均有统计学意义(P0.05),涂氟后3~4 h尿氟浓度达到高峰,至21 h后与涂氟前比较差异无统计学意义(P0.05);3岁0.2 m L组与0.05 m L组在涂氟后2~4 h的尿氟浓度比较差异有显著性(P0.05),其他时间比较均无显著性差异(P0.05);0.05 m L3岁组与4岁组比较尿氟浓度无明显差别(P0.05);3岁初次用氟组和4岁多次用氟组涂氟前尿氟无显著差异(P0.05)。结论:儿童口腔局部用氟对其尿氟浓度有影响,随局部用氟剂量的增加而增加;年龄对儿童尿氟浓度无明显影响;Duraphat在体内无远期氟蓄积,在一定剂量内使用Duraphat可起到较好的防龋效果。     

Comparison between amine fluoride and chlorhexidine with institutionalized elders: a pilot study

doi: 10.1111/j.1741‐2358.2012.00650.x Comparison between amine fluoride and chlorhexidine with institutionalized elders: a pilot study Objective: Compare the efficacy of amine fluoride toothpaste and gel with chlorhexidine spray in an institutionalised population. Background: People who live in nursing homes have poorer oral hygiene because of their dependency for the basic activities of daily living as they rely on caregivers. Methods: Twenty‐six people over 65 years old who had at least four teeth and living in a nursing home. They were assigned to three groups: A: amine fluoride toothpaste and once a week amine fluoride gel (Elmex^®), B: 0.12% spray‐chlorhexidine once a day (Perio‐Aid^®) and C: brush teeth without toothpaste. The plaque and gingival index of Silness and Löe, General Oral Health Assessment Index, McLeran and Pfeiffer index were recorded, and the number of colonies of Streptoccocus mutans and Lactobacillus and the remineralisation of caries were evaluated using Diagnodent^®. Measurements were taken at the beginning of the study and after 6 months. Results: Twenty‐two people finished the study. No group showed a statistical difference in the plaque or gingival index, but there was a tendency to show improvement in the amine fluoride group. There was also no difference between the number of colonies of either S. mutans or lactobacillus. There was a significant difference between the plaque and gingival index and the cognitive status (p = 0.0054), along with their requirement for assistance to perform good oral hygiene (p = 0.0001). Both products remineralised the carious lesions in this period compared with the control group (p = 0.0151). Conclusion: The plaque and gingival indices did not improve during the study, but both products remineralised the previous caries lesions.     

Fluoride-Induced Oxidative Stress in Rat’s Brain and Its Amelioration by Buffalo (<Emphasis Type="Italic">Bubalus bubalis</Emphasis>) Pineal Proteins and Melatonin

Fluoride (F) becomes toxic at higher doses and induces some adverse effects on various organs, including brain. The mechanisms underlying the neurotoxicity caused by excess fluoride still remain unknown. The aims of this study were to examine F-induced oxidative stress (OS) and role of melatonin (MEL) and buffalo pineal proteins (PP) against possible F-induced OS in brain of rats. The 24 rats were taken in present study and were divided into four groups: control, F, F + PP, and F + MEL. The F group was given 150 mg/L orally for 28 days. Combined 150 ppm F and 100 μg/kg BW (i.p.) PP and F (150 ppm) + MEL (10 mg/kg BW, i.p.) were also administered. The activities of enzymatic, viz., superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT), glutathione reductase (GR), and non-enzymatic, viz., reduced glutathione (GSH) concentration, and the levels of malondialdehyde (MDA) in the brain tissue were measured to assess the OS. Fluoride administration significantly increased brain MDA compared with control group, while GSH levels were decreased in fluoride-treated groups, accompanied by the markedly reduced SOD, GPx, GR, and SOD activity. Buffalo PP and MEL administration caused brain MDA to decrease but caused SOD, GPx, GR, GSH, and CAT activities to increase to significant levels in F-treated animals. Together, our data provide direct evidence that buffalo PP and MEL may protect fluoride-induced OS in brain of rats through mechanisms involving enhancement of enzymatic and non-enzymatic antioxidant defense system. Therefore, this study suggested that PP and MEL can be useful in control of neurotoxicity induced by fluoride.     

Use of an immobilized cell bioreactor for the continuous inoculation of milk in fresh cheese manufacturing

A system was developed to continuously acidify and inoculate skim milk for the production of fresh cheese. Four strains of mesophilic lactic acid bacteria were entrapped separately in κ -carrageenan/locust bean gum gel beads and used in a stirred bioreactor operated at 26°C with a 25% (v/v) gel load. The pH in the reactor was controlled at 6.0 by adding fresh milk using proportional integrated derived regulation. The bioreactor was operated during 8-h daily cycles for up to 7 weeks with different milks (heat treatment, dry matter content) and differing starting procedures. The heat treatment of the milk was an important factor for process performance: a dilution rate increase of 57% and an inoculation level decrease of 63% were observed with sterilized UHT skim milk (142°C – 7.5 s) compared with pasteurized skim milk (72°C – 15 s). The dry matter content of the milk (8–13% w/w) had no detectable effect on these parameters. A convenient starting procedure of the system was tested; steady-state was reached in less than 40 min following an interruption period of 16–60 h. These results combined with our published data on process performance show the feasibility of using an integrated immobilized cell bioreactor for milk prefermentation in cheese manufacture. Received 10 June 1996/ Accepted in revised form 15 October 1996     

Investigation of Supragingival Plaque Microbiota in Different Caries Status of Chinese Preschool Children by Denaturing Gradient Gel Electrophoresis

This study aimed to detect differences in the richness of total supragingival plaque microbiota as well as the species composition of oral streptococci involved in the different stages of dental caries. Forty-five plaque samples were collected from caries-moderate (CM, 4 ≤ dmfs ≤ 6), caries-susceptible (CS, dmfs ≥ 10), and age-matched caries-free children separately. Total DNA was isolated directly from each sample, and polymerase chain reaction–denaturing gradient gel electrophoresis (PCR-DGGE) analyses using universal and primers specific for oral streptococci were carried out. Using 16S rDNA PCR-DGGE, 34 different species of bacteria were identified in a culture-independent manner and classified into 11 genera according to phylogenetic analysis. Among them, Mitis group streptococci and Campylobacter, which were present in health status, no longer appeared in caries-susceptible samples. In addition, Capnocytophaga, Burkholderia, and Prevotella were found significantly less frequently in the CS group samples (P < 0.05), while there were no significant differences among the prevalence of Neisseria, Leptotrichia, Haemophilus, Mutans group streptococci, Corynebacterium, and Actinomyces in the three groups. Further DGGE analysis of rnpB gene amplicons obtained with oral streptococci species-specific primers showed that a total of 23 species of oral streptococci were identified. Streptococcus sanguinis, Streptococcus mitis, and Streptococcus oralis showed a significantly higher prevalence in healthy children (P < 0.05), while that of Streptococcus mutans and Streptococcus sobrinus did not vary among the three groups. Overall, these results suggest that supragingival plaque microbiota as a whole undergoes a more complicated shift in the caries process.     

Effects of Zinc Supplementation on Physical Growth in 2–5-Year-Old Children

Physical growth disorders in under 5-year-old children are a common health problem in many countries including Iran. The aim of this study was to determine effects of supplemental zinc on physical growth in preschool children with retarded linear growth. This study was a community-based randomized controlled trial on 2–5-year-old children with height-for-age below 25th percentile of National Center for Health Statistics growth chart. Ninety children were randomly assigned in zinc group (ZG) or placebo group (PG). After 6 months of zinc or placebo supplementation, we followed up the children for another 6 months. Anthropometric indicators were measured before the intervention and then monthly for 11 months. Forty children in ZG and 45 in PG concluded the study. Zinc supplementation increased weight gain in boys (P = 0.04) and girls (P = 0.05) compared to placebo but had no significant effect on mid-upper arm circumference increment in either sexes. The most significant (P = 0.001) effect of Zinc supplementation was seen in boys’ height increment at the end of follow-up period. Stunted growth rate in ZG changed significantly (P = 0.01) from 26.7% to 2.5% throughout the study. This study showed that daily supplementation of 5 mg elemental zinc for 6 months improves physical growth in terms of height increment and weight gain in children with undesirable linear growth, especially in boys.     

Effect of Thiolated Polymers to Textural and Mucoadhesive Properties of Vaginal Gel Formulations Prepared with Polycarbophil and Chitosan

The aim of this study was to design and evaluate of mucoadhesive gel formulations for the vaginal application of clomiphene citrate (CLM) for local treatment of human papilloma virus (HPV) infections. Chitosan (CHI) and polycarbophil (PC) were covalently modified using the thioglycolic acid and L-cysteine, respectively. The formation of thiol conjugates of chitosan (CHI-TG) and polycarbophil (PC-CYS) were confirmed by FT-IR analysis and PC-CYS and CHI-TG were found to have 148.42 ± 4.16 and 41.17 ± 2.34 μmol of thiol groups per gram of polymer, respectively. One percent CLM gels were prepared by combination of various concentrations of PC and CHI with thiolated conjugates of these polymers. Hardness, compressibility, elasticity, adhesiveness and cohesiveness of the gels were measured by Texture profile analysis and the vaginal mucoadhesion was investigated by mucoadhesion test. The increasing in the amount of the thiol conjugates was found to enhance the elasticity, cohesiveness, adhesiveness and mucoadhesion of the gel formulations but not their hardness and compressibility when compared to gels prepared using their respective parent formulations. Slower release rate of CLM from gels was achieved when the polymer concentrations were increased in the gel formulations. PC and its thiol conjugate were found to prolong the release of CLM longer than 70 h unlike gel formulations prepared using CHI and its thiol conjugate which were able to release CLM up to 12 h. Stability of CLM was preserved during the 3 month stability analysis under controlled room temperature and accelerated conditions.     

Effect of Fluoride Exposure on Serum Glycoprotein Pattern and Sialic Acid Level in Rabbits

This study describes the effects of fluoride exposure on the protein profile, glycoprotein pattern, and total sialic acid concentration of serum in rabbits. For this aim; 20 healthy New Zealand rabbits were used. The rabbits were divided into two equal groups each with ten animals according to their weighing: control group and experimental group. The rabbits in control group were given drinking tap water containing 0.29 mg/l sodium fluoride and experimental group received the same tap water to which was added 40 mg/l sodium fluoride for 70 days. Blood samples were taken from each rabbit on day 70. Serum fluoride concentrations were measured by a fluoride-specific ion electrode in serum. The fluoride levels in the serum were found as 18.4 (±1.58) μg/L in control and 301.3 (±52.18) μg/L in fluoride exposed rabbits. The sialic acid levels were found as 69.2 (±0.32) mg/dL in control and 43.4 (±0.13) mg/dL in fluoride exposed group. The electrophoretic patterns of serum proteins, glycoproteins, and total sialic acid concentration were determined. Fifteen different protein fractions with molecular weights ranging from 22 to 249 kDa were displayed in the serum protein electrophoretic gel of both groups. The raw concentrations of the protein fractions decreased in fluoride exposed rabbits as compared with the control rabbits. The serum glycoprotein pattern revealed seven major protein bands from 47 to 167 kDa in experimental and control groups. The slight decrease of raw concentration of the protein bands in glycoprotein pattern of serum was observed in fluoride toxication comparing to control. The results suggest that serum TSA determination and serum protein electrophoresis can be used to evaluate prognosis of fluoride exposure as a supplementary laboratory test in combination with clinical and other laboratory findings of fluorosis.     

The Application of Modified Flow-Through Cell Apparatus for the Assessment of Chlorhexidine Dihydrochloride Release from Lozenges Containing Sorbitol

The objective of this work was to apply a new apparatus for the assay of the drug release from lozenge tablet with a potential use in the treatment of oral candidosis and another conditions connected to microbial etiopathology in the oral cavity or as an antiplaque factor. Also, an approach to comparison of the applied method with the classical paddle apparatus method was performed. Tablets containing chlorhexidine dihydrochloride were formulated with granulated sorbitol of different grades (diameter of 110, 180, 480, and 650 μm, respectively), lactose, and magnesium stearate as excipients. Tablets were obtained through direct compression, and uniformity of weight, friability, breaking strength, disintegration, and release rate were evaluated. The disintegration times ranged between 10 and 21 min. In the next stage of the study, the release of chlorhexidine from lozenges prepared with granulated sorbitol grade 110 μm and different amounts of lactose and magnesium stearate was assessed. Two stages were observed during the release of chlorhexidine dihydrochloride from the lozenges, assayed by the classical paddle apparatus method II USP. In the first stage, release rates were between 2.6 × 10⁻² and 4.7 × 10⁻² min⁻¹, in the second stage between 1.7 × 10⁻³ and 7.7 × 10⁻³ min⁻¹. In the case of the in-house method, the release was near to first-order kinetics through the entire release experiment, with rate constants between 3.6 × 10⁻² and 6.6 × 10⁻² min⁻¹. The sorbitol granulate of granules with diameter 110 μm was found to be most suitable for the lozenges with chlorhexidine dihydrochloride and lactose. The in-house release method, proposed in this work, seems to be more realistic for the preliminary assessment of predicted drug concentrations in the oral cavity after the intake of a lozenge.