Biomedical subjects

J A Cury

Publications and source records attributed to J A Cury.

At least 37 records · Page 2Linked to original sources

PubMed2002

Effects of apigenin and tt-farnesol on glucosyltransferase activity, biofilm viability and caries development in rats.

Propolis, a resinous hive product secreted by Apis mellifera bees, has been shown to reduce the incidence of dental caries in rats. Several compounds, mainly polyphenolics, have been identified in propolis. Apigenin and tt-farnesol demonstrated biological activity against mutans streptococci. We determined here their effects, alone or in combination, on glucosyltransferase activity, biofilm viability, and development of caries in rats. Sprague-Dawley rats were infected with Streptococcus sobrinus 6715 and treated topically twice daily as follows: (1) tt-farnesol, (2) apigenin, (3) vehicle control, (4) fluoride, (5) apigenin +tt-farnesol, and (6) chlorhexidine. Apigenin (1.33 mM) inhibited the activity of glucosyltransferases in solution (90-95%) and on the surface of saliva-coated hydroxyapatite beads (35-58%); it was devoid of antibacterial activity. tt-Farnesol (1.33 mM) showed modest antibacterial activity against biofilms and its effects on glucosyltransferases were minimal. The incidence of smooth-surface caries was significantly reduced by apigenin +tt-farnesol (60%), fluoride (70%), and chlorhexidine (72%) treatments compared to control (P < 0.05).

Analysis of Variance↗

PubMed2002

Effect of triclosan dentifrices on mouth volatile sulphur compounds and dental plaque trypsin-like activity during experimental gingivitis development.

BACKGROUND: The objective of this study was to evaluate the effect of three commercial anti-plaque dentifrices containing 0.3% triclosan + 2% pvm/ma (Colgate Total), 0.3% triclosan + 0.75% Zn (Signal Global) and 0.3% triclosan + 5% PPi (Crest Complete) in comparison with an experimental dentifrice (0.3% triclosan + 2% pvm/ma + 0.75% Zn + 4% PPi) and a control dentifrice without anti-plaque agents on trypsin-like activity in dental plaque (detected by the hydrolysis of [Na-Benzoyl-DL-Anginine p-Nitroanilide (BAPNA)] and volatile sulphur compounds (VSCs) in mouth air during experimental gingivitis development. METHOD: A 5-step double blind, crossover experimental gingivitis study was conducted on 19 volunteers during a 21-day period. The volunteers refrained from brushing an experimental quadrant of teeth. The dentifrices were applied to those teeth via toothshield three times per day; simultaneously they brushed the other teeth with the same dentifrice. After each period, VSCs in mouth air and BAPNA hydrolysis by dental plaque accumulated in the experimental quadrant were determined. RESULTS: There was an increase (p < 0.05) in VSCs in mouth air when experimental gingivitis was induced in only one quadrant of teeth. None of the dentifrices was able to avoid the increase of VSCs during the experimental gingivitis development. The majority of the antiplaque dentifrices evaluated reduced the increase of VSC formation in comparison with the control (p < 0.05). There was no relationship between the ability of the dentifrices in reducing VSC formation and the inhibition of trypsin-like activity in dental plaque. CONCLUSIONS: Anti-plaque dentifrices reduce the increase of VSCs that occurs during the development of experimental gingivitis.

Adult↗

PubMed2001

[Fluoride intake by children from water and dentifrice].

OBJECTIVE: To determine the total fluoride dose to which children were exposed during the critical age of developing dental fluorosis, in an optimally fluoridated region, having diet (liquids and solids) and dentifrice as fluoride sources. METHODS: For the pilot study, 39 children (aged 20 to 30 months) were selected from a day care center in Piracicaba, Brazil. They drank and ate food prepared with fluoridated water. To determine the total dose of fluoride exposure, duplicate-plate samples and products from tooth brushing were collected for two consecutive days, in four periods of the year. Fluoride was determined using an ion specific electrode. A 5% level of significance variance analysis (Anova) was carried out. RESULTS: Children were exposed to a total fluoride dose of 0.090 mg/day/kg of body weight, of which 45% came from the diet and 55% from dentifrice. CONCLUSIONS: Assuming 0.07 mg/kg as a threshold value of fluoride systemic exposure, children were exposed to a risk dose for dental fluorosis. Thus, measures to reduce fluoride intake at the studied age range would be recommended. Reducing the amount of dentifrice used for tooth brushing seems to be the best measure, given the risk/benefits of fluoride use from the public health perspective.

Cariostatic Agents↗

PubMed2001

In situ study of sucrose exposure, mutans streptococci in dental plaque and dental caries.

The purpose of this study was to investigate the relationship among frequency of sucrose exposure, mutans streptococci levels and dental caries. Adult volunteers took part in this crossover study performed in 4 phases of 28 days each. The volunteers wore intra-oral palatal appliances containing blocks of human dental enamel and dripped 20% sucrose solution onto the dental blocks from 0 to 8 times/day. After each phase, the colony forming units (CFU) were determined in dental plaque and enamel dental caries was evaluated using cross-sectional hardness. Sucrose frequency had no statistically significant effect on mutans streptococci levels. In the enamel cross-sectional hardness tests, significant differences (p < 0.05) in relation to area of mineral loss were observed only when sucrose exposure was 8 times/day. Similar results were obtained when cross-sectional hardness was assessed at each distance from enamel surface.

Adult↗

PubMed2000

Effect of a new variety of Apis mellifera propolis on mutans Streptococci.

The effects of a new variety of propolis, from Northeastern Brazil (BA), on growth of mutans streptococci, cell adherence, and water-insoluble glucan (WIG) synthesis were evaluated. Propolis from Southeastern (MG) and Southern (RS) Brazil were also tested as an extension of our previous work. Ethanolic extracts of propolis (EEP) were prepared and analyzed by reversed-phase HPLC. For the antibacterial activity assays, minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) of EEPs against Streptococcus mutans, S. sobrinus, and S. cricetus were determined. Cell adherence of S. mutans and S. sobrinus to a glass surface was measured spectrophotometrically at 550 nm. WIG synthesized from sucrose by glucosyltransferase (Gtf) was extracted and quantified by the phenol-sulfuric method. The HPLC profile of the new variety of propolis was entirely different from Southeastern and Southern propolis. Neither flavonoid aglycones nor p-coumaric acid were detected in EEP BA. All EEPs demonstrated biological activities against mutans streptococci; EEP BA showed the highest potency in all in vitro parameters evaluated in this study. The ranges of MIC values were 50 (EEP BA)-400 microg/ml (MG), for S. mutans; and 25 (BA)-400 microg/ml (MG), for S. sobrinus and S. cricetus. The bactericidal concentration of EEPs was four to eight times the MIC values. The adherence of S. mutans and S. sobrinus cells and WIG synthesis were markedly inhibited by EEPs, demonstrating significant inhibition at all concentrations compared with the control (80% ethanol) (p<0.05). EEP BA showed 80% inhibition of cell adherence and WIG synthesis at concentrations as low as 12.5 and 7.8 microg/ml, respectively. The results show that the new variety of propolis was exceptionally effective in all in vitro parameters tested against mutans streptococci; biological effects of propolis are likely not to be due solely to flavonoids and (hydroxy)cinnamic acid derivatives.

Animals↗

PubMed2000

In vitro antimicrobial activity of propolis and Arnica montana against oral pathogens.

Arnica and propolis have been used for thousands of years in folk medicine for several purposes. They possess several biological activities such as anti-inflammatory, antifungal, antiviral and tissue regenerative, among others. Although the antibacterial activity of propolis has already been demonstrated, very few studies have been done on bacteria of clinical relevance in dentistry. Also, the antimicrobial activity of Arnica has not been extensively investigated. Therefore the aim here was to evaluate in vitro the antimicrobial activity, inhibition of adherence of mutans streptococci and inhibition of formation of water-insoluble glucan by Arnica and propolis extracts. Arnica montana (10%, w/v) and propolis (10%, w/v) extracts from Minas Gerais State were compared with controls. Fifteen microorganisms were used as follows: Candida albicans--NTCC 3736, F72; Staphylococcus aureus--ATCC 25923; Enterococcus faecalis--ATCC 29212; Streptococcus sobrinus 6715; Strep. sanguis--ATCC 10556; Strep. cricetus--HS-6; Strep. mutans--Ingbritt 1600; Strep. mutans--OMZ 175; Actinomyces naeslundii--ATCC 12104, W 1053; Act. viscosus OMZ 105; Porphyromonas gingivalis; Porph. endodontalis and Prevotella denticola (the last three were clinical isolates). Antimicrobial activity was determined by the agar diffusion method and the zones of growth inhibition were measured. To assess cell adherence to a glass surface, the organisms were grown for 18 h at 37 degrees C in test-tubes at a 30 degree angle. To assay water-insoluble glucan formation, a mixture of crude glucosyltransferase and 0.125 M sucrose was incubated for 18 h at 37 degrees C in test-tubes at a 30 degree angle. Arnica and propolis extracts (20 microl) were added to these tubes to evaluate the % of inhibition of cell adherence and water-insoluble glucan formation. The propolis extract significantly inhibited all the microorganisms tested (p < 0.05), showing the largest inhibitory zone for Actinomyces spp. The Arnica extract did not demonstrate significant antimicrobial activity. Cell adherence and water-insoluble glucan formation were almost completely inhibited by the propolis extract at a final concentration of 400 microg/ml and 500 microg/ml, respectively. The Arnica extract showed slight inhibition of the adherence of the growing cells (19% for Strep. mutans and 15% for Strep. sobrinus) and of water-insoluble glucan formation (29%) at these same concentrations. Thus, the propolis extract showed in vitro antibacterial activity, inhibition of cell adherence and inhibition of water-insoluble glucan formation, while the Arnica extract was only slightly active in those three conditions.

Actinomyces↗

PubMed2000

Effect of 3 dentifrices containing triclosan and various additives. An experimental gingivitis study.

BACKGROUND: The antiplaque and antigingivitis effect of 3 dentifrices was evaluated using the 21-day partial-mouth experimental model of gingivitis. METHOD: 25 volunteers took part in this cross-over, double-blind study, carried out in 4 phases of 21 days each. For each phase of the study, a toothshield of the IV quadrant was constructed for each volunteer. 2 antiplaque dentifrices from the market, one containing triclosan + pvm/ma and the other triclosan + Zn, were compared with an experimental formulation and its placebo. The experimental dentifrice contained triclosan + pvm/ma + Zn + PPi and the placebo (control) did not contain these substances. The subjects were stratified according to their whole-mouth baseline plaque (PI), gingivitis (GI) and bleeding (BI) index scores, and then randomly assigned to 1 of 4 dentifrices. During each phase, while the volunteers brushed their teeth with one of the dentifrices, the IV quadrant was protected by the toothshield filled with the dentifrice used. After each phase, dental plaque, gingivitis and bleeding indices were determined. RESULTS: The results showed that only the formulation containing triclosan + pvm/ma + Zn + PPi was able to reduce PI (28.8%), GI (35.9%) and BI (30.4%) in comparison with controls (p<0.05). CONCLUSIONS: The data suggest that a dentifrice containing the combination of triclosan + pvm/ma + Zn + PPi should be formulated for dental plaque control.

Adolescent↗

PubMed2000

Fluoride effect on the activity of enamel matrix proteinases in vitro.

Dental fluorosis is common in individuals exposed to different sources of fluoride during tooth development. The mechanism causing this enamel defect is still unknown. Enamel matrix proteinases play a central role in the maturation of dental enamel, and inhibition of these enzymes by fluoride has been one explanation for dental fluorosis. We have investigated the effect of fluoride on the activity of enamel matrix proteinases using a colorimetric assay, casein zymography, and an enamel protein degradation assay. Fluoride (625 microM to 10 mM) inhibited neither the enzymatic activity of the crude matrix extract nor the activity of individual enamel enzymes separated by SDS-PAGE. The proposition that fluoride could directly inhibit enzymes was not confirmed in this study.

Analysis of Variance↗

PubMed2000

Effect of lead, cadmium and zinc on the activity of enamel matrix proteinases in vitro.

Environmental contamination with heavy metals leads to their uptake by the body. Dental tissues are known to harbor metals in concentrations related to the exposure at the time of dentin or enamel formation. Several enzymes involved in the metabolism of extracellular matrix components have been shown to be inhibited by excess metal ions. Enamel matrix proteinases seem to play a central role in the maturation of dental enamel, and inhibition of these enzymes by metals could interfere with amelogenesis. We have investigated the effect of lead, cadmium and zinc on the activity of enamel matrix proteinases using a colorimetric assay, casein and gelatin zymography, and an assay of enamel protein degradation in vitro. All three metals inhibited the proteolysis, as shown by the three methods employed, in concentrations as low as 110 microM. This study showed that contaminant metals can inhibit proteinolysis when a crude enamel extract containing enamel proteases is tested in vitro. Therefore, the presence of heavy metals in enamel matrix could interfere with amelogenesis due to alteration in normal proteolysis.

Amelogenesis↗

PubMed2000

Effect of saccharin on antibacterial activity of chlorhexidine gel.

Although chlorhexidine is the most effective agent against dental plaque it is extremely bitter. To prepare formulations, it is necessary to use flavoring and sweetening, which can inhibit the antibacterial effect of chlorhexidine. Saccharin has been considered a compatible substance to use in chlorhexidine rinse or gel preparations; however, the effect of a range of concentrations has not been studied. To evaluate the effect of different concentrations of saccharin on the antibacterial activity of chlorhexidine gel, hydroxy-ethyl-cellulose gels containing 1.0% chlorhexidine digluconate and 0.0 to 1.0% sodium saccharin were prepared. Activity against Streptococcus mutans was evaluated using the agar diffusion method and determination of MIC values. The inhibitory zones of growth were 7.83 +/- 0.54 mm when no saccharin was added to the chlorhexidine gel and 7.75 +/- 0.50, 7.63 +/- 0.48, 6.21 +/- 0.40, 4.13 +/- 0.38, when the concentrations of saccharin in the gels were 0.02, 0.10, 0.5, and 1.0%, respectively. The range of MIC values was 1-2 micrograms/ml, with saccharin concentrations of 0%, 0.02, and 0.1%. In contrast, the MIC values were 4-8 and 8-16 micrograms/ml with saccharin concentrations of 0.5% and 1.0%, respectively. The paired "t" test showed that 0.5 and 1.0% sodium saccharin inhibit the antibacterial activity of 1% digluconate chlorhexidine gel. These in vitro results suggest that saccharin may inhibit the efficacy of chlorhexidine against mutans streptococci, depending on the concentration.

Anti-Infective Agents, Local↗

PubMed1998

Antimicrobial activity of propolis on oral microorganisms.

Formation of dental caries is caused by the colonization and accumulation of oral microorganisms and extracellular polysaccharides that are synthesized from sucrose by glucosyltransferase of Streptococcus mutans. The production of glucosyltransferase from oral microorganisms was attempted, and it was found that Streptococcus mutans produced highest activity of the enzyme. Ethanolic extracts of propolis (EEP) were examined whether EEP inhibit the enzyme activity and growth of the bacteria or not. All EEP from various regions in Brazil inhibited both glucosyltransferase activity and growth of S. mutans, but one of the propolis from Rio Grande do Sul (RS2) demonstrated the highest inhibition of the enzyme activity and growth of the bacteria. It was also found that propolis (RS2) contained the highest concentrations of pinocembrin and galangin.

Actinomyces↗

PubMed1998

Soluble calcium/SMFP dentifrice: effect on enamel fluoride uptake and remineralization.

PURPOSE: To evaluate in situ the effect of soluble calcium on fluoride uptake and remineralization by human dental enamel from a sodium monofluorophosphate (SMFP) dentifrice. MATERIALS AND METHODS: Eight volunteers took part in this cross-over, double-blind design study performed in three phases of 45 days. During each phase of the experiment, the subjects wore an acrylic resin appliance containing four blocks of human dental enamel with artificial caries to evaluate fluoride uptake and remineralization by three dentifrices: SMFP containing CaCl2, SMFP, and placebo. After each phase, the enamel blocks were removed and the total fluoride uptake (ppm F) and microhardness (Knoop) were measured. Statistical analyses (ANOVA and Turkey's test) were done. RESULTS: There was no statistically significant difference between SMFP-CaCl2 and SMFP treatments regarding the amount of fluoride and microhardness data of treated enamel blocks as well as their areas under the curves, although both differed significantly (P < 0.05) when they were compared with placebo. However, the SMFP-CaCl2 treatment demonstrated the highest values on fluoride uptake and microhardness data. Furthermore, the microhardness data demonstrated 50% and 40% of remineralization for SMFP-CaCl2 and SMFP dentifrices, respectively.

Analysis of Variance↗

PubMed1998

Inhibition of demineralization in vitro around amalgam restorations.

OBJECTIVE: The purpose of this in vitro study was to evaluate some forms of preventing or avoiding demineralization within enamel cavity walls adjacent to amalgam restorations. METHODS AND MATERIALS: Third molar teeth were sectioned to obtain 72 specimens, divided into one control and five experimental groups: amalgam only; varnish plus amalgam; acidulated phosphate fluoride plus amalgam; adhesive amalgam; glass-ionomer cement plus amalgam; control (amalgam only, not subjected to a demineralization challenge). The experimental groups were subjected to PH and thermal cycling and then submitted to enamel hardness determinations. RESULTS: Significant differences between the treatment groups revealed that the bonded amalgam technique offered the best resistance to demineralization. The use of cavity varnish resulted in greater mineral loss than amalgam placed alone. CONCLUSION: The use of an adhesive system, glass-ionomer cement, or acidulated phosphate fluoride under amalgam restorations may interfere with development of secondary caries.

Acidulated Phosphate Fluoride↗

PubMed1997

In situ relationship between sucrose exposure and the composition of dental plaque.

The aim of this study was to analyze the composition of dental plaque according to sucrose exposure. Twelve adult volunteers took part in this crossover study done in four phases of 28 days each. For each phase of the study, an acrylic resin appliance containing four human dental enamel blocks was constructed for each volunteer. A 20% sucrose solution was dripped onto the enamel blocks from 0 to 8 times/day. The volunteers were randomly assigned to the treatments. During the experimental period all the subjects used fluoride-free dentifrice, refrained from brushing the enamel blocks and drank water fluoridated at 0.70 ppm F. After each phase the concentrations of fluoride (F), calcium (Ca), phosphorus (P) and total carbohydrate were determined in dental plaque. Statistical analyses showed that frequent sucrose exposure significantly (p < 0.05) reduced the F, Ca and P concentrations in dental plaque, but increased the alkali-soluble carbohydrate concentration. The results suggest that the cariogenicity of dental plaque formed in the presence of sucrose cannot be attributed only to its higher porosity, but the lower inorganic concentration may also be important.

Adult↗

PubMed1997

VariGlass fluoride release and uptake by an adjacent tooth.

PURPOSE: To quantitatively analyze in vitro the fluoride release from proximal VariGlass restorations and resulting uptake by the enamel of adjacent teeth. MATERIALS AND METHODS: Sixty impacted third molars were used and assigned to three groups: C: control, teeth without restorations; RC: teeth with resin composite restorations (Prisma APH); and PMRC: teeth with polyacid-modified resin composite restorations (VariGlass). Each group consisted of four sets of five teeth each. In the latter two sets, by alternating restored and unrestored teeth, the proximal surfaces of three unrestored teeth with an area of exposed enamel were in contact with the restored proximal surfaces of two other teeth. The sets were submitted to high caries challenge conditions with demineralizing and remineralizing solutions for 14 days. The fluoride of each solution and the fluoride uptake were determined and statistical analyses were carried out (ANOVA and Tukey's test). RESULTS: The highest mean fluoride concentration occurred with Group PMRC in both kinds of solutions (P < 0.01), but this value was higher in the demineralizing solution (P < 0.01). Over the 14 days, however, this mean gradually decreased in both solutions (P < 0.01). Group PMRC also showed the highest mean fluoride uptake (P < 0.01), which gradually decreased with depth in the enamel (P < 0.01).

Acrylic Resins↗

PubMed1996

[Evaluation of fluoride content of bottled drinking waters in Brazil].

The utilization of a systemic fluoride method must be controlled in terms of risks and benefits. The reason for this is that while a small dose will not be effective in preventing dental caries, a larger dose may cause dental fluorosis. Therefore the knowledge of the fluoride concentration found in the bottled mineral waters sold throughout the Brazilian market the consumption of which has increased lately, is of great concern. The objective of the study was the analysis of the concentration of fluoride found in the bottled mineral waters. A hundred and four brands coming from different regions of Brazil were analysed using an Orion 96-09 ion specific electrode and an Orion EA 940 ionanalyser. previously calibrated with standard fluoride solutions. Different concentrations of fluoride ranging from 0.0 to 4.4 were found. It was discovered that specific bottled waters contained: 1) Significant concentrations of fluoride not reported by the producer; 2) Fluoride concentrations of no preventive effect, although the producer had advertised the water as a Fluoridated Mineral Water; 3) Fluoride concentrations high enough to cause dental fluorosis, although the producer did not alert the consumer to this fact. It is to be concluded, therefore, that a sanitary regulatory system for the control of the level of fluoride in the bottled mineral waters marketed is necessary. Such reputation should be formulated in terms of benefits as well as in terms of risks.

Brazil↗

PubMed1994

Glass ionomer cement surface protection.

PURPOSE: To evaluate the effectiveness of various surface treatments for glass ionomer cement (GIC) by determining quantity of dye uptake spectrophotometrically. MATERIALS AND METHODS: Sixty specimens, 4.5 mm diameter and 2 mm thick, were made from Shofu GIC and divided into 10 groups. Positive control (A) and negative control (B) specimens were not protected while experimental specimens were protected with ARM chemically-cured bonding resin (C), Durafill Bond light-cured bonding resin (D), Bondlite light-cured bonding resin (E), Colorama nail varnish (F), Shofu varnish (G), Copalite varnish (H), Vaseline (I) or Vaseline followed by Copalite (J). The discs were immersed in 0.05% methylene blue solution 10 minutes after mixing except group B specimens which were immersed in deionized water. After 24 hours the discs were removed, washed, and individually placed in 1 ml 65% nitric acid for 36 hours. The solutions were filtered, centrifuged and the absorbance determined spectrophotometrically at 590 nm. Dye uptake was expressed in microgram dye/restoration and the data analyzed by ANOVA and Tukey Kramer test. RESULTS: The mean (SD) of dye uptake were: A:95.12 (11.28); B:0 (0); C:40.90 (5.06); D:33.89 (3.63); E:35.73 (3.36); F:3.29 (0.79); G:14.87 (2.86); H:21.99 (3.25); I:47.21 (7.06); J:29.74 (3.49). All the surface agents were effective in protecting setting restorative glass ionomer cement, but nail varnish provided the best results.

Analysis of Variance↗

PubMed1994

Effect of Plax prebrushing rinse on enamel fluoride deposition.

This in vitro study evaluated the effect of Plax prebrushing rinse on fluoride uptake by enamel from sodium fluoride (NaF) and sodium monofluorophosphate (MFP) solutions in the presence and in the absence of saliva. Human enamel powder (particle size between 0.074 and 0.149 mm), pretreated or not with Plax, was exposed to aqueous solution of 250 ppm F as either NaF or MFP. The exposure time was 1 minute followed by washing in deionized water and methanol. The amounts of alkali-soluble fluoride (CaF2) and firmly bound fluoride (FBF) on enamel were determined with a specific electrode and statistically analyzed with ANOVA. Plax reduced the formation of both CaF2 and FBF on enamel whether the F was supplied as NaF or MFP. The percentage inhibition of uptake from NaF was increased and that from MFP was decreased by the presence of saliva. The commercial prebrushing rinse formulation tested inhibits in vitro the reactivity of the fluoride with enamel.

Analysis of Variance↗