Physical properties and enamel remineralization potential of arginine-fluoride varnishes.

OBJECTIVE: The study objectives were to examine the physical properties and enamel remineralization potential of fluoride (F) varnishes incorporated with arginine (Arg). METHODS: Four commercial F varnishes: 1) Duraphat®; 2) Flúor Protector®, 3) Fluor Protector S®, and 4) Fluorimax™ were supplemented with 2% w/v. Arg. The control/experimental varnishes underwent rheometric analysis to assess varnish density (δ), velocity (ν), and associated viscosity, both quantitatively (ν/δ) and qualitatively based on determined mass, volume, distance flow, and time under experimentation. The varnish wet/dry weights (at 2 h) were also analysed. Further, sound enamel specimens (T0) with artificial incipient caries-like lesions (T1) were treated with control/experimental varnishes and subjected to remineralization assay with artificial saliva for 6 h. Thereafter (T2), the specimens were characterized to estimate precipitated Ca and net enamel F uptake. Additionally, mineral density (MD) was assessed using micro-CT at T0, T1, and T2 to derive mineral gain (MG) and % remineralization for the treatment groups. RESULTS: When Arg is incorporated, the physical properties of the F-containing varnishes undergo a significant transformation, resulting in higher density, varnish weight, dry varnish weight, and viscosity compared to their respective control varnishes (p < 0.05). Incorporating Arg-in Duraphat®, Fluor Protector S®, and Fluorimax™ significantly improved both enamel Ca precipitation and F uptake compared to the respective controls (p < 0.05). Additionally, the enamel F uptake was significantly higher with all the tested varnishes when enriched with Arg (p < 0.05). The combined data for MD, MG, and % remineralization suggests that the remineralization potential of F-varnishes significantly increased when enriched with Arg (p < 0.05). CONCLUSION: Incorporating Arg in inorganic F varnishes improves their physical properties and enhances the enamel remineralization potential of the varnishes. CLINICAL SIGNIFICANCE: This study highlights the possibility of incorporating Arg in distinct F-source varnishes. The synergism between active components (Arg-F) aids in enhanced remineralization and superior varnish physical properties, demonstrating a promising approach for high caries-risk patients.

Dual protective effect of the association of plant extracts and fluoride against dentine erosion: In the presence and absence of salivary pellicle.

OBJECTIVES: To verify the protective effect of plant extracts associated with fluoride against dental erosion of dentine, in the presence and absence of a salivary pellicle. METHODS: Dentine specimens (n = 270) were randomly distributed into 9 experimental groups (n = 30/group): GT (green tea extract); BE (blueberry extract); GSE (grape seed extract); NaF (sodium fluoride); GT+NaF (green tea extract and NaF); BE+NaF (blueberry extract and NaF); GSE+NaF (grape seed extract and NaF); negative control (deionized water); and a positive control (commercialized mouthrinse containing stannous and fluoride). Each group was further divided into two subgroups (n = 15), according to the presence (P) or absence (NP) of salivary pellicle. The specimens were submitted to 10 cycles: 30 min incubation in human saliva (P) or only in humid chamber (NP), 2 min immersion in experimental solutions, 60 min of incubation in saliva (P) or not (NP), and 1 min erosive challenge. Dentine surface loss (dSL-10 and dSL-total), amount of degraded collagen (dColl) and total calcium release (CaR) were evaluated. Data were analyzed with Kruskal-Wallis, Dunn's and Mann-Whitney U tests (p>0.05). RESULTS: Overall, the negative control presented the highest values of dSL, dColl and CaR, and the plant extracts showed different degrees of dentine protection. For the subgroup NP, GSE showed the best protection of the extracts, and the presence of fluoride generally further improved the protection for all extracts. For the subgroup P, only BE provided protection, while the presence of fluoride had no impact on dSL and dColl, but lowered CaR. The protection of the positive control was more evident on CaR than on dColl. CONCLUSION: We can conclude that the plant extracts showed a protective effect against dentine erosion, regardless of the presence of salivary pellicle, and that the fluoride seems to improve their protection.

In vitro effect of low-fluoride toothpaste supplemented with sodium trimetaphosphate, xylitol, and erythritol on enamel demineralization.

OBJECTIVE: Regular use of toothpaste with fluoride (F) concentrations of ≥ 1000 ppm has been shown to contribute to reducing caries increment. However, when used by children during the period of dental development, it can lead to dental fluorosis. In this study, we aimed to evaluate the in vitro effect of a toothpaste formulation with reduced fluoride (F) concentration (200 ppm) supplemented with sodium trimetaphosphate (TMP: 0.2%), Xylitol (X:16%), and Erythritol (E: 4%) on dental enamel demineralization. METHODOLOGY: Bovine enamel blocks were selected according to initial surface hardness (SHi) and then divided into seven experimental toothpaste groups (n=12). These groups included 1) no F-TMP-X-E (Placebo); 2) 16% Xylitol and 4% Erythritol (X-E); 3) 16% Xylitol, 4% Erythritol and 0.2%TMP (X-E-TMP); 4) 200 ppm F (no X-E-TMP: (200F)); 5) 200 ppm F and 0.2% TMP (200F-TMP); 200 ppm F, 16% Xylitol, 4% Erythritol, and 0.2% TMP (200F-X-E-TMP); and 7) 1,100 ppm F (1100F). Blocks were individually treated 2×/day with slurries of toothpastes and subjected to a pH cycling regimen for five days (DES: 6 hours and RE: 18 hours). Then, the percentage of surface hardness loss (%SH), integrated loss of subsurface hardness (ΔKHN), fluoride (F), calcium (Ca), and phosphorus (P) in enamel were determined. The data were analyzed by ANOVA (1-criterion) and the Student-Newman-Keuls test (p<0.001). RESULTS: We found that the 200F-X-E-TMP treatment reduced %SH by 43% compared to the 1100F treatments (p<0.001). The ΔKHN was ~ 65% higher with 200F-X-E-TMP compared to 1100F (p<0.001). The highest concentration of F in enamel was observed on the 1100F treatment (p<0.001). The 200F-X-E-TMP treatment promote higher increase of Ca and P concentration in the enamel (p<0.001). CONCLUSION: The association of 200F-X-E-TMP led to a significant increase of the protective effect on enamel demineralization compared to the 1100F toothpaste.

In vitro evaluation of the effects of different particle types in toothpastes on the efficacy against enamel erosion and wear.

The effects of the particle fraction in toothpastes in the context of erosion and erosive tooth wear has not been fully elucidated. Thus, aim of this study was to investigate experimental toothpastes, each with one specific particle type. Toothpastes with seven different types of silica or alumina were prepared as slurry either with or without active ingredients (NaF or F/Sn). Human enamel samples were exposed to a cyclic erosion/abrasion model, and were either treated with the respective slurries only or additionally brushed in a brushing machine. Tissue loss was profilometrically monitored. After treatment with slurries without active ingredients or with NaF, tissue loss increased significantly within groups over time (p < 0.001 each). At the end of the trial, there were minor differences between groups (not exceeding 10-20%; p > 0.05 for most comparisons). After treatment with the F/Sn slurries, tissue loss stagnated completely over time, with the exception of one silica type and alumina, but both still reduced tissue loss by 40-50% (compared to control p < 0.001 each). Relative to the type of the active ingredient, the particle type seems to be a secondary factor for the efficacy of toothpastes on erosion and erosive tooth wear in enamel.

Vitamin C and E supplementation can ameliorate NaF mediated testicular and spermatozoal DNA damages in adult Wistar rats.

OBJECTIVE: Present study was designed to explore the efficacy of vitamin C and E (VC&VE) against fluoride mediated testicular, epididymal and spermatozoal anomalies. MATERIALS AND METHODS: Thirty two adult Wistar rats were divided into four groups. Group-I was control; Group-II received sodium fluoride (NaF) at 15 mg/kg/day dose; Group-III was provided with VC (200 mg/kg/day) and VE (400 mg/kg/day) plus NaF; Group-IV received only VC&VE. Structural integrity and oxidative stress markers (superoxide dismutase, catalase, malondialdehyde and protein carbonyl) of testis and epididymis were assessed. Spermatozoal parameters (count, motility, viability and hypo-osmotic swelling) were evaluated. Testicular functional maker enzymes (acid phosphatase, alkaline phosphatase and lactate dehydrogenase) were also assessed. Integrity of testicular and spermatozoal DNA was evaluated. Testicular fluoride content was measured. RESULT: Fluoride induced structural changes and alterations of oxidative stress markers were observed in testis and epididymis. Spermatozoal potentials were altered and reduced activities of testicular functional marker enzymes were observed. Fluoride caused testicular and spermatozoal DNA damages. VC&VE supplementation resulted in protection from all fluoride mediated alterations and helped in attenuating testicular fluoride accumulation. CONCLUSION: Antioxidant properties of VC&VE ameliorated fluoride mediated reproductive damages but only supplementation did not exhibit any notable effect compared to control rats.

DOES TITANIUM TETRAFLUORIDE PROMOTE A PROTECTIVE EFFECT ON ERODED TOOTH? A SYSTEMATIC REVIEW AND META-ANALYSIS.

OBJECTIVE: This systematic review and meta-analyses aimed to evaluate the potential protective effect of titanium tetrafluoride (TiF4) compound compared to sodium fluoride (NaF) on eroded enamel or dentin. METHODS: Two independent reviewers searched PubMed, Scopus, Web of Science, LILACS, Cochrane, EMBASE, and Open gray Literature up to June 2020. MeSH terms, supplementary concepts, synonyms, and free terms were applied based on PICOS strategy (P- population: eroded enamel or dentin; I- intervention: eroded teeth treated with solution or varnish of TiF4; C- comparison: eroded teeth treated with a solution or varnish of NaF; O- outcome: mineral loss measurement; S- study design: in vitro studies). Seven distinct parameters evaluated the risk of bias, and all studies were submitted to 4 meta-analyses (first and second meta-analyses related to enamel loss treated with fluoride solution or varnish, respectively; third and fourth meta-analyses related to dentin loss treated with fluoride solution or varnish, respectively). A sensitivity test was performed by the RevMan software, based on standard mean difference calculation (P < .05). RESULTS: A total of 10,260 studies were retrieved, from which 22 studies were included in systematic review through eligibility criteria, of which 1 study was classified as low risk of bias, 19 as medium, and 3 as high. Seventeen studies were included in 4 different meta-analyses, presenting considerable overall heterogeneity (I2 = 95; 92; 95; and 93%, respectively) with statistical significance for TiF4 on the first meta-analysis, and no statistical significance for second, third, and fourth meta-analyses. CONCLUSIONS: Titanium tetrafluoride compound delivered as solution provided significant effective protection for erosion lesions on the enamel surface compared to sodium fluoride. However, when TiF4 or NaF were applied on enamel or dentin surfaces as varnish, both provided the same effective protection, based on in vitro studies with considerable heterogeneity.

Assessment of the Remineralizing Efficacy of Grape Seed Extract vs Sodium Fluoride on Surface and Subsurface Enamel Lesions: An In Vitro Study.

AIM: The aim of this study was to evaluate the efficacy of grape seed extract (GSE) on remineralization of surface and subsurface enamel lesions compared to that of sodium fluoride (NaF). MATERIALS AND METHODS: A total of 20 intact bovine incisor crowns were separated from their roots and immersed in a demineralizing solution for 96 hours at 37°C to create artificial enamel lesions. The specimens were randomly divided into two groups (n = 10): 6.5% GSE solution and 1000 ppm NaF solution. The specimens were subjected to six daily pH cycles for 8 days. The microhardness test was carried out at three different stages: baseline, after artificial caries formation, and after pH cycling. Raman spectroscopy was used to evaluate the depth of enamel remineralization. Surface morphology and elemental analysis were assessed using a scanning electron microscope (SEM) and an energy dispersive X-ray (EDX) spectroscope, respectively. Statistical analysis was performed using SPSS 22.0 at a significance level of p ≤ 0.05. RESULTS: There was a significant increase in the mean values of enamel surface microhardness after pH cycles in the two groups compared to after artificial caries formation, but there was no significant difference between both groups. The B-type carbonate/phosphate (Ca/P) ratio at 10 and 40 µm depth revealed no significant difference between the two groups. Scanning electron microscope micrograph revealed occlusion of porosities and particle precipitation on the enamel surface of the two groups, while EDX results for the Ca/P ratio of the GSE and NaF groups were 1.59 and 1.60, respectively. CONCLUSION: Grape seed extract and NaF are equally effective in remineralizing surface and subsurface artificial enamel lesions. CLINICAL SIGNIFICANCE: Grape seed extract can be considered a promising herbal material and a safe alternative to traditional NaF for the noninvasive treatment of enamel lesions.

Amelioration of sodium fluoride induced oxidative stress by Cynometra travancorica Bedd in mice.

OBJECTIVES: Cynometra travancorica, endemic to Western Ghats of India is pharmacologically similar to Saraca asoca and occasionally used as substitute in a well-known Ayurvedic uterine tonic Asokarishta. S. asoca possess various biological properties, but there are no reports on C. travancorica. The present study evaluated the pharmacological properties of C. travancorica and its efficacy in attenuating the sodium fluoride (NaF) induced oxidative stress in mice. METHODS: Antioxidant potential of methanolic extract of C. travancorica (CTE) stem bark was evaluated using DPPH, superoxide radical scavenging and total antioxidant assays. The effect of CTE on mitigating NaF deteriorated redox status in the liver tissue of mice was evaluated. Functional groups in CTE were analyzed by FTIR analysis. RESULTS: CTE effectively scavenged the free radicals in in vitro condition. CTE could augment catalase (46.6%), superoxide dismutase (53.8%) activities and GSH level (48.1%) against NaF induced decline in the liver tissue of mice. The peroxidation of lipids was found to be decreased by 44.9% and tissue damage abated as inferred by histopathology. FTIR analysis revealed the presence of biologically active functional groups in CTE. CONCLUSIONS: The study revealed the ameliorative effect of C. travancorica against NaF induced deleterious effect in experimental animals by its potent antioxidant potential.

Recent Development of Active Ingredients in Mouthwashes and Toothpastes for Periodontal Diseases.

Periodontal diseases like gingivitis and periodontitis are primarily caused by dental plaque. Several antiplaque and anti-microbial agents have been successfully incorporated into toothpastes and mouthwashes to control plaque biofilms and to prevent and treat gingivitis and periodontitis. The aim of this article was to review recent developments in the antiplaque, anti-gingivitis, and anti-periodontitis properties of some common compounds in toothpastes and mouthwashes by evaluating basic and clinical studies, especially the ones published in the past five years. The common active ingredients in toothpastes and mouthwashes included in this review are chlorhexidine, cetylpyridinium chloride, sodium fluoride, stannous fluoride, stannous chloride, zinc oxide, zinc chloride, and two herbs-licorice and curcumin. We believe this comprehensive review will provide useful up-to-date information for dental care professionals and the general public regarding the major oral care products on the market that are in daily use.

The Effects of a Toothpaste Containing the Active Ingredients of Galla chinensis and Sodium Fluoride on Dentin Hypersensitivity and Sealing of Dentinal Tubules: An In Vitro Study and an Eight-Week Clinical Study in 98 Patients.

BACKGROUND This study aimed to evaluate the desensitizing effect of toothpaste containing the active ingredients of an extract of Galla chinensis, both in vitro and in patients with dentin hypersensitivity. MATERIAL AND METHODS Ninety-eight patients with dentin hypersensitivity were divided into two study groups and given toothpaste containing either the active ingredients of Galla chinensis extract and sodium fluoride, or a control toothpaste containing only sodium fluoride. Assessments included the tactile stimulation test and the Schiff cold air sensitivity scale, which were conducted at the baseline examination and after 4 and 8 weeks of dental brushing. Twenty-five intact human premolars from 24 patients with dentin hypersensitivity were prepared and randomly divided into four groups, the untreated baseline group, the study group, the positive control group, and the control group. After brushing with different toothpaste for 7 days, the effects on dentinal tubule sealing in each group was determined by scanning electron microscopy (SEM), and the degree of dentinal tubule plugging and diameter of the open dentinal tubules were calculated. RESULTS Toothpaste containing the active ingredients of Galla chinensis and sodium fluoride significantly reduced the degree of dentin hypersensitivity when compared with toothpaste containing sodium fluoride alone after 4 weeks and 8 weeks of use. Toothpaste containing the active ingredients of Galla chinensis significantly reduced the number and diameter of the open dentinal tubules. CONCLUSIONS Toothpaste that contained the active ingredients of Galla chinensis and sodium fluoride reduced the symptoms of dentin hypersensitivity by sealing the dentinal tubules.

Effects of lemon essential oil and limonene on the progress of early caries: An in vitro study.

OBJECTIVE: The purpose of this study was to investigate the effects of Lemon essential oil (LEO) and Limonene (LIM) in the progress of early caries. DESIGN: LEO and LIM were selected as experimental medicine, while sodium fluoride (NaF) and deionized water (DW) were positive and blank controls, respectively. Bovine incisors were used to establish enamel and dentin early caries models by demineralization method in vitro. Then specimens were subjected to pH cycling. Calcium and phosphate release of demineralizing solution were measured by an automatic biochemical analyzer; Surface microhardness tester and energy dispersive X-ray spectrometer were used to detect the surface microhardness recovery and calcium- phosphate ratio on tooth surface; Degraded collagen matrix by collagenase was investigated by assaying hydroxyproline. RESULTS: Calcium release of dentin demineralizing solution of LEO group was lower than DW group's and higher than NaF group's. Both of LEO and LIM groups, the surface microhardness recovery were significantly lower than those of NaF group, which were similar to DW group. Dentin surface calcium- phosphate ratio of LEO and LIM groups were lower than those of NaF group and higher than those of DW group. Hydroxyproline concentration in the remineralizing solution of LEO and LIM groups were lower than DW groups' and higher than NaF groups'. CONCLUSIONS: LEO and LIM have influence on the progress of dentin early caries, which can stabilize its structure by inhibiting collagen degradation. Meanwhile, these medicines may provide a new drug choice for the prevention and treatment of early root caries.

Plant DNases are potent therapeutic agents against Echis carinatus venom-induced tissue necrosis in mice.

Echis carinatus envenomation leads to severe tissue necrosis at the bitten site by releasing DNA from immune cells that blocks the blood flow. An earlier report has shown that exogenous DNase 1 offers protection against such severe local tissue necrosis. Tricosanthus tricuspidata is a medicinal plant and the paste prepared from its leaves has been used extensively for the treatment of snakebite-induced tissue necrosis. Most studies including reports from our laboratory focused on plant secondary metabolite as therapeutic molecules against snakebite envenomation. However, the involvement of hydrolytic enzymes including DNase in treating snake venom-induced tissue necrosis has not been addressed. Several folk medicinal plants used against snakebite treatment showed the presence of DNase activity and found to be rich in T. tricuspidata. Further, purified T. tricuspidata DNase showed a single sharp peak in reversed-phase high-performance liquid chromatography (RP-HPLC) with an apparent molecular mass of 17 kDa. T. tricuspidata DNase exhibited potent DNA degrading activity performed using agarose gel electrophoresis, spectrophotometric assay, and DNA zymography. In addition, purified DNase from T. tricuspidata was able to neutralize E. carinatus venom-induced mouse tail tissue necrosis and normalized elevated serum creatine kinase (CK) and lactate dehydrogenase (LDH) levels 30 minutes post venom injection. T. tricuspidata DNase was also able to reverse E. carinatus venom-induced histopathological changes and collagen depletion in mice tail tissue. All these observed pharmacological actions of T. tricuspidata DNase were inhibited by sodium fluoride (NaF). This study provides scientific validation of the traditional use of T. tricuspidata leaf paste in the healing of snakebite-induced tissue necrosis and might be exploited to treat snake venom-induced local toxicity.

Evaluation of Physical Parameters of Novel Licorice Varnish Versus Fluoride and Combination Varnish: An In-Vitro Study.

OBJECTIVES: The aim of this study was to evaluate the physical properties of locally prepared Licorice varnish (LV), commercially available Fluoride varnish (FV) and a Combination of both Varnishes (CV). MATERIAL AND METHODS: LV was prepared using authenticated licorice roots. Commercially available FV (Bifluorid 12) was used as a positive control and CV was prepared in six different concentrations of both varnishes. Conventional antibacterial activity assessment, employing disc diffusion and broth dilution methods, was inconclusive. Therefore a novel assessment method was used, whereby the varnish was directly added to a mixture of Brain Heart Infusion broth with Streptococcus mutans and incubated. Physical parameters such as pH, rate of evaporation, viscosity, film forming ability, and cost incurred for preparation were assessed and compared. RESULTS: FV, LV and CV (except the combination of LV 80% + FV 20%) showed antibacterial activity against Streptococcus mutans. All three varnishes formed films on the tooth surface as confirmed by Scanning Electron Microscopy. Mean pH was in the range of 4-4.5, viscosity 48-52 centipoise (cP), rate of evaporation was 150-160 seconds. They were comparable to each other in the physical parameters tested, except for the shelf life of LV. CONCLUSION: All three varnishes showed antibacterial activity against Streptococcus mutans which was established using an innovative method of antibacterial activity assessment. LV was most economical of all but had a shorter shelf life. The results of this study need to be evaluated through an in vivo study.

A comparative evaluation of the anticaries efficacy of herbal extracts (Tulsi and Black myrobalans) and sodium fluoride as mouthrinses in children: A randomized controlled trial.

BACKGROUND: Dental caries is a multifactorial disease in which microorganisms play an important role. Recently, herbs have been tried as mouthrinses to combat the side effects of chemical mouthrinses. The anticaries efficacy of Sodium fluoride, Tulsi leaf, and Black myrobalans fruit extracts on Streptococcus mutans (S. mutans) have been reported in the literature, but no comparative study has been done yet. AIM: This study aims to observe the change in the pH of saliva and to assess the efficacy of the herbal rinses-Tulsi and Black myrobalans on S. mutans count while comparing it with Sodium fluoride mouthrinse. METHODS: Herbal ethanolic extracts of Tulsi (4%) and Black myrobalans (2.5%) were prepared as mouthrinses and compared with sodium fluoride mouthrinse (0.05%). Sixty high caries risk patients were selected and allocated randomly into three groups [n = 20], categorized as Group A-Sodium fluoride mouthrinse, Group B-Tulsi mouthrinse, and Group C-Black myrobalans mouthrinse. They were instructed to rinse their mouth with their assigned mouthrinses for 7 days. Salivary samples were collected and sent to the laboratory at baseline, 1 h postrinsing and after 7th day of rinsing for determining the salivary pH and S. mutans count. The increase in pH and reduction of S. mutans were determined. The values obtained were tabulated and statistically analyzed. RESULTS: There was a significant increase in the salivary pH and reduction in S. mutans count after rinsing in all the three groups. Increase in salivary pH was more in the Sodium fluoride mouthrinse when compared to the experimental herbal groups (Group B and Group C). While S. mutans counts reduced more with Tulsi mouthrinse at 1 h postrinsing and after the 7th day of rinsing more reduction was seen in Black myrobalans mouthrinse group. CONCLUSION: The results of the study suggest that herbal mouthrinses could be tried as an adjunctive anticaries agent against dental caries causing microorganisms.

Evaluation of bacterial flora composition on teeth and periodontal tissues in patients in treatment with rapid palatal expander.

Patients in treatment with rapid palatal expander (RPE) require professional assistance and more meticulous instructions on oral hygiene, since this appliance predisposes to gingivitis and caries. The aim of this work is to analyse the variability of the oral microbial flora found in patients in treatment with RPE with occlusal acrylic splint. It was also investigated whether the association of an antimicrobial mouthwash was useful during orthodontic treatment or whether regular and specific home oral hygiene manoeuvres were sufficient to maintain a good plaque control. The last goal was to highlight which of the different mouthwashes was the most effective in reducing the bacterial load. The patients were divided into 3 test groups and each one of them had a different mouthwash (chlorhexidine and sodium fluoride, fluorine, essential oils) randomly assigned. There was also a control group. Plaque samples were analysed through cultural analysis and PCR from T0 to T4 (8 months). Chlorhexidine mouthwash reduces the bacterial count by 96.08%, the fluorine by 94.50% and the essential oils by 95.74%. The results of the three mouthwashes are superimposable and although chlorhexidine gives the highest rate of bacteria reduction, its side effects lead the authors to prefer the essential oils.

Use of sodium trimetaphosphate in the inhibition of dentin matrix metalloproteinases and as a remineralizing agent.

OBJECTIVES: Because of its ability to act as an antiproteolytic agent, the effect of sodium trimetaphosphate (STMP) against specific enzymes extracted from sound dentin and its performance under acidic challenge on demineralized dentin were investigated. METHODS: The antiproteolytic potential of STMP (0.5%, 1.0%, and 1.5%) was assessed in triplicate by zymography. For the evaluation of remineralization activity, 50 bovine-root dentin specimens were selected and randomly divided into 5 groups (n=10). Three areas were determined for each specimen: 1) control (no treatment); 2) demineralized (artificial caries-like challenge); 3) treated (demineralized and subjected to pH-cycling for 7days, and treated for 10min with 1.5% STMP, 1.5% STMP+calcium hydroxide (Ca[OH]2), 1.5% STMP+sodium fluoride (NaF), NaF, or deionized H2O). The dentin specimens were analyzed for superficial hardness (SH) and cross-sectional hardness (CSH) at different depths (10, 30, 50, 70, 90, 110, and 220µm) using a Knoop penetrator (10g/10s). Statistical analyses were performed with analysis of variance (ANOVA) and Tukey tests (p<0.05). RESULTS: The zymographic analysis showed that 1.5% STMP promoted complete inhibition of gelatinolytic activity. Therefore, 1.5% STMP was investigated in association with supplemented calcium or fluoride; a combination of 1.5% STMP and Ca(OH)2 significantly increased the mechanical properties of the treated dentin. CONCLUSION: 1.5% STMP serves as an antiproteolytic agent against matrix metalloproteinases extracted from human dentin. Furthermore, when supplemented with Ca(OH)2, 1.5% STMP may potentially induce remineralization. CLINICAL SIGNIFICANCE: STMP can be introduced as a novel strategy that combines enzymatic inhibition and remineralizing potential, which can serve to strengthen dentin and improve stability. STMP may have potential in the treatment of demineralized dentin lesions, especially when supplemented with calcium.

Ameliorative effect of Azadirachta indica on sodium fluoride-induced hypertension through improvement of antioxidant defence system and upregulation of extracellular signal regulated kinase 1/2 signaling.

BACKGROUND: Toxicities due to fluoride exposure from natural and industrial sources occur commonly in man and animals with severe consequences ranging from mild cardiac derangements to sudden death. In this study, we investigated the protective effects of the methanol extract of Azadirachta indica (AI) against sodium fluoride (NaF)-induced hypertension and genotoxicity in rats. METHODS: Sixty rats were divided into six groups of ten rats each as follows: Group A, the control group received distilled water; Group B rats were administered NaF at 600 ppm in drinking water; Groups C and D rats were pre-treated with the methanol extract of AI and thereafter administered NaF at 600 ppm in drinking water for 7 consecutive days; Groups E and F rats were co-administered with AI and NaF. RESULTS: The administration of NaF caused significant (p<0.05) increases in the blood pressure, markers of oxidative stress, serum myeloperoxidase, xanthine oxidase values in NaF-alone treated rats, compared with the control. Significant (p<0.05) decreases were observed in cardiac and renal antioxidant defence system in rats administered NaF alone compared with the control group. NaF treatment also resulted in a reduction in the expressions of extracellular signal-regulated kinase (ERK) 1/2 in cardiac and renal tissues of NaF-treated rats. Moreover, NaF treatment elicited an increase in the frequency of micronucleated polychromatic erythrocytes when compared with the control group. CONCLUSIONS: This study shows the protective effect of AI on NaF-induced hypertension and genotoxicity through antioxidant and ERK 1/2 signaling in rats.

The effects of fluoride on neuronal function occurs via cytoskeleton damage and decreased signal transmission.

It has been reported that fluoride exposure may cause serious public health problems, particularly neurotoxicity. However, the underlying mechanisms remain unclear. This study used Neuro-2A cells to investigate the effects of fluoride on the cytoskeleton. The Neuro-2A cells were exposed to 0, 1, 2, 4 and 6 mM sodium fluoride (NaF) for 24 h. Cell viability and lactate dehydrogenase (LDH) release were examined. It was observed that exposure to NaF reduced cell viability, disrupted cellular membrane integrity, and high levels of LDH were released. The observed changes occurred in a dose response manner. Morphologic observations showed that cell became rounded and were loosely adherent following exposure to NaF. Axon spines and normal features disappeared with high dose NaF treatment. The expression of MAP2 and synaptophysin decreased, particularly at 4 mM and 6 mM (P < 0.05) for MAP2. These results corroborate the morphologic observations. The content of glutamate and NMDAR (glutamate receptor) protein were assessed to help understand the relationship between synapses and neurotransmitter release using ELISA and Western-blot. Compared with the control, glutamate and NMDAR expression declined significantly at 4 mM and 6 mM (P < 0.05) group. Finally, the ultrastructural changes observed with increasing doses of NaF were: disappearance of synapses, mitochondrial agglutination, vacuole formation, and cellular edema. Taken together, NaF exposure disrupted cellular integrity and suppressed the release of neurotransmitters, thus effecting neuronal function. These findings provide deeper insights into roles of NaF in neuron damage, which could contribute to a better understanding of fluoride-induced neurotoxicity.

Comparison of the Streptococcus mutans and Lactobacillus colony count changes in saliva following chlorhexidine (0.12%) mouth rinse, combination mouth rinse, and green tea extract (0.5%) mouth rinse in children.

BACKGROUND: Compounds present in green tea have been shown to inhibit the growth and activity of bacteria associated with oral infections. The purpose of this study was to compare the efficacy of chlorhexidine (0.12%) mouth rinse and combination (chlorhexidine and sodium fluoride) mouth rinse to that of green tea extract (0.5%) mouth rinse in reducing the salivary count of Streptococcus mutans and Lactobacillus in children. MATERIALS AND METHODS: The sample for the study consisted of 75 school children aged 8-12 years with four or more (decay component) of decayed, missing, and filled teeth index. Children were divided randomly into three equal groups and were asked to rinse with the prescribed mouth rinse once daily for 2 weeks after breakfast under supervision. Nonstimulated whole salivary sample (2 ml) was collected at baseline and postrinsing and tested for the colony forming units of S. mutans and Lactobacillus. RESULTS: The results of the study indicate that there was a statistically significant reduction in S. mutans and lactobacilli count in all the three study groups. The statistically significant reduction in the mean S. mutans and lactobacilli counts were more in 0.12% chlorhexidine group than in the combination mouth rinse and 0.5% green tea mouth rinse group. There was no statistically significant difference in the reduction of S. mutans and lactobacilli count between combination mouth rinse group and 0.5% green tea mouth rinse group. CONCLUSION: Green tea mouth rinse can be a promising preventive therapy worldwide for the prevention of dental caries.

Induction of apoptosis and ganoderic acid biosynthesis by cAMP signaling in Ganoderma lucidum.

Apoptosis is an essential physiological process that controls many important biological functions. However, apoptosis signaling in relation to secondary metabolite biosynthesis in plants and fungi remains a mystery. The fungus Ganoderma lucidum is a popular herbal medicine worldwide, but the biosynthetic regulation of its active ingredients (ganoderic acids, GAs) is poorly understood. We investigated the role of 3',5'-cyclic adenosine monophosphate (cAMP) signaling in fungal apoptosis and GA biosynthesis in G. lucidum. Two phosphodiesterase inhibitors (caffeine and 3-isobutyl-1-methylxanthine, IBMX) and an adenylate cyclase activator (sodium fluoride, NaF) were used to increase intracellular cAMP levels. Fungal apoptosis was identified by terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) assay and a condensed nuclear morphology. Our results showed that GA production and fungal apoptosis were induced when the mycelium was treated with NaF, caffeine, or cAMP/IBMX. Downregulation of squalene synthase and lanosterol synthase gene expression by cAMP was detected in the presence of these chemicals, which indicates that these two genes are not critical for GA induction. Transcriptome analysis indicated that mitochondria might play an important role in cAMP-induced apoptosis and GA biosynthesis. To the best of our knowledge, this is the first report to reveal that cAMP signaling induces apoptosis and secondary metabolite production in fungi.