I Iványi

Semmelweis University, Budapeŝto, Budapest, Hungary

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Publications (16)14.44 Total impact

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    ABSTRACT: Endothelial cell proliferation, angiogenesis, and increased vascular permeability are among the effects of vascular endothelial growth factor (VEGF) in various organs. However, the effects of VEGF on gingival hemodynamics, especially on venules, have not been thoroughly investigated. This study investigated the acute circulatory effects of VEGF on rat gingival venules. Fifty-six anesthetized rats were divided into five study groups; each rat received 10 microl of experimental solution dripped onto the lower interincisal gingiva. The groups included: 1) saline control (after the experiment, gingiva was excised for VEGF receptor 2 [VEGFR2] immunohistochemistry); 2) VEGF (0.1, 1, 10, or 50 microg/ml); 3) VEGF2 receptor antagonist 5-((7-benzyloxyquinazolin-4-yl)amino)-4-fluoro-2-methyl-phenol-hydrochloride (ZM323881; 20 microg/ml); 4) ZM323881 (20 microg/ml) followed by VEGF application (50 microg/ml after 15 minutes); and 5) VEGF (10 microg/ml), these rats were premedicated with nitric oxide (NO) synthase blocker (N(G)-nitro-L-arginine-methyl-ester [L-NAME]; 1 mg/ml in drinking water) for 1 week before the experiment. Changes in gingival superficial venule diameter were measured by vital microscopy prior to and 1, 5, 15, 30, and 60 minutes after the administration of the experimental solutions. VEGF dose-dependently increased the venular diameter compared to saline. ZM323881 alone did not cause any alteration. Premedication with ZM323881 or L-NAME decreased the dilatory effects of VEGF. VEGFR2 immunohistochemical labeling was observed in the wall of the venules. There is no remarkable VEGF production under physiologic circumstances in rat gingiva, but VEGF is able to increase gingival blood flow through the activation of VEGF2 receptors. Furthermore, NO release may contribute to VEGF's vasodilatory effect.
    Journal of Periodontology 10/2009; 80(9):1518-23. · 2.40 Impact Factor
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    ABSTRACT: Many new devices and instruments have been developed in the field of endodontics, however, even today guttapercha is the most commonly used root canal filling material and lateral condensation is still widely the technique of choice. It is crucial that the guttapercha point should not bend away during insertion into the root canal, and that the size of the guttapercha point is in accordance with the size-coding marked on the container. However, there is no data on the difference between the dimensional accuracy and the rigidity of guttapercha points produced by various manufacturers. The aim of the authors' study was to compare guttapercha points of different brands (ANTEOS, DENTSPLY, DIADENT, EXPORDENT, FKG, META, ROEKO, ROSA BECHT, SURE ENDO). The rigidity of guttapercha points (n = 10 in each group) and the dimensional accuracy has been measured (n = 10 in each group) with an instrument developed for this purpose. Statistical analysis has been performed by ANOVA, level of significance was (p < 0.05). In the group FKG significant (p < 0.05) higher forces were necessary to bend guttapercha points. No other significant difference has been shown between the investigated groups (p > 0.05). In the dimensional accuracy there were significant differences (p < 0.05). The least deviation from the assigned dimension has been found in the ROSABECHT group, and the highest in the FKG group. In the dimensional accuracy the least standard error has been found in ROSABECHT group, and the highest in EXPORDENT group. The most extreme deviations have been shown in META and DENTSPLY group. The results of the present study show that guttapercha points frequently deviate from the marked dimension: a guttapercha point from the ISO 25 container may even reach the size of an ISO 30 guttapercha. This has to be taken into account during root canal obturation.
    Fogorvosi szemle 05/2008; 101(2):65-9.
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    ABSTRACT: Accurate determination of root canal length is essential for successful endodontic therapy. Two methods are generally accepted for working length measurements: radiographic length determination and by the means of electronic apex locators. The purpose of this study was to evaluate the working length determination habits of Hungarian dentists using a survey form containing 15 selective closed questions for data collection. The results indicate that 70% of the dentists preferred the radiographic method. 19% of the responders employ electronic apex locator. 21% of dentists relied on fingertip tactile sense or on the patient's response. 44% of the responders determined the working length after pulp tissue removal. 22% of dentists make the measurements at the end of root canal instrumentation. 34% of the dentists disregard the evaluation of the preoperative radiographs for the estimated working length determination. The results suggest that whilst most of the general practitioners use the techniques currently taught in dental schools, a large proportion of them apply methods not accepted by contemporary dental profession.
    Fogorvosi szemle 03/2007; 100(1):33-9.
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    ABSTRACT: Local application of dental bond materials can cause pulpal vasodilation and hyperemia. Such local hemodynamic changes may be mediated by alterations in the levels of locally generated nitric oxide (NO). In different species systemic administration of NO synthase inhibitors leads to a decrease in pulpal blood flow. In contrast, the local administration of these inhibitors has not been tested yet. Therefore, the effect of locally blocked NO synthase on the internal diameter of rat pulpal arterioles under basal conditions and immediately after dental bond material application was studied by using vitalmicroscopic technique. The NO synthase blocker (L-NAME) was locally administered on a thinned dentine layer of the left lower incisor. L-NAME reduced the diameter of the pulpal arteriole both in basal and after bond material-induced hyperaemic conditions. These data suggest that the local formation of NO may have a significant role in the acute vasodilation induced by bond material application and also in maintenance of basal pulpal arteriolar tone.
    Life Sciences 09/2005; 77(12):1367-74. · 2.56 Impact Factor
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    ABSTRACT: In this study, we compared the antimicrobial efficacy of various root canal preparation techniques and instruments in the root canals of 40 human first maxillary premolars extracted for orthodontic reasons. After extirpation of the pulp, teeth were sterilized in an autoclave. Then, the root canals were infected with Enterococcus faecalis suspension and the teeth incubated at 37 degrees C for 24 h. Thereafter, the teeth were divided into five groups: preparation with K-file or K-Nitiflex file (step-back technique; groups 1 and 2), K-reamer (standardization technique; group 3), irrigation only (group 4), and no treatment (group 5). Before and after treatments, samples were taken for culture. Results were evaluated after 24-h incubation in E67 selective culture medium. We observed a considerable reduction in bacterial population after mechanical preparation. No significant differences were seen among the efficacy of the various preparation techniques and files used.
    Journal of Endodontics 09/2002; 28(8):603-5. · 2.93 Impact Factor
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    ABSTRACT: In this study root canal preparation methods and instruments were compared by using forty extracted upper first bicuspids. The trepanated and extirpated teeth were sterilised in an autoclave, inoculated with Enterococcus faecalis and incubated for 24 hours at 37 degrees C. The teeth were divided into 5 groups as follows: those treated with K-file and K-file Nitiflex (step back technique, 1st, 2nd groups), with K-reamer (standard technique, 3rd group), those rinsed only with sterile saline solution (4th group), and those left untouched after incubation (5th group). Bacterial samples were taken before and after preparation and were inoculated onto special E67 plates. The plates were evaluated after 24 hours of incubation. It was concluded that the number of the bacteria could be significantly reduced with rinsing and mechanical preparation. There was no significant difference as to the efficacy of the preparation procedures or instruments applied.
    Fogorvosi szemle 01/2002; 94(6):253-5.
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    ABSTRACT: Despite great progress in the production of new dental polymers, application of these products is still controversial. The unlined utilization of cytotoxic adhesive materials on pulpal dentin can adversely influence the pulp, leading to alterations in local microcirculation that can be an early sign of pathological changes. In a previous study by the authors, the effect of an acetone-free bondmaterial was examined on the vascular diameter of pulpal vessels by means of vitalmicroscopy. In this study, experiments comparing experimental data provided by an acetone-containing bondmaterial to these earlier findings with acetone-free ones have been performed. Thirty male Sprague-Dawley rats (weighing 333+/-9 g) were used for this investigation. The first lower incisor was prepared for vitalmicroscopy. Changes in vessel diameter were recorded prior to and 5, 15, 30 and 60 minutes after the investigated materials (Scotchbond Multi-Purpose Dental Adhesive System or Prime & Bond 2.1) were administered on dentin as recommended by the manufacturer. In control rats (saline administration), the vessel diameter was stable during the experiment. In the presence of acetone-free bondmaterial (Scotchbond), the vessel diameter was increased during the experimental period in relation to the baseline (12.15+/-2.85%; 16.36+/-2.39%; 14.16+/-3.48%; 12.12+/-3.72%). In the presence of acetone-containing bondmaterial (Prime & Bond 2.1), a similar result was observed (10.56+/-2.27%; 16.13+/-2.94%; 17.88+/-2.54%; 14.54+/-3.16%). The differences between the control values and those registered with test groups were significant (p<0.05; ANOVA). There was no significant difference among the test groups. The results of this study suggest that dental bond materials applied on a very thin layer of dentin may affect the blood supply to the dental pulp. However, no stasis or prestasis has been detected, indicating a possible reversible effect. The authors could not show any statistical difference between the vasodilatation caused by the acetone-containing and the acetone-free bond material.
    Operative Dentistry 01/2002; 27(4):367-72. · 1.31 Impact Factor
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    ABSTRACT: Experimental stimulation and clinical procedures applied on the crown of the tooth cause vascular reaction in the dental pulp. Laser-Doppler flowmetry is a good method for determining the blood flow of the dental pulp. The aim of these experiments was to study the acute effect of a calcium hydroxide-containing pulp-capping material (Dycal, DeTrey) on blood flow of the dental pulp after the application into a deep test-cavity. Two groups of male Sprague-Dawley rats (308 g +/- 50 S.E.) were used: control- and test-group, n = 10. A standardised deep class five cavity was prepared in the left lower incisor of each rat. Laser-Doppler flowmeter was used to measure the vascular reaction of the pulp. The levels of blood flow were recorded prior to (0 min.) and after the application (1, 5, 15, 30, 60 min.) of Dycal. Results were evaluated with one-way ANOVA. Significantly higher pulpal blood flow was found only in the first minute after the application of Dycal. In any other time no significant difference was found between the results before and after (5, 15, 30, 60 min.) the application in test- and control-group.
    Fogorvosi szemle 07/2001; 94(3):107-9.
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    ABSTRACT: Conditioning agents used on dentin with composite materials are biologically active and may have deleterious effects on the pulpal microcirculation. No data are available on the immediate vascular effect of etching materials applied on a constant thin pulpal dentin. In this study the authors examined whether the application of 36% phosphoric acid (Conditioner 36, 15 seconds) or itakonic acid with 10% maleic acid (NRC Non-Rinse Conditioner, 20 seconds), as recommended by the manufacturers, alters the blood circulation in the pulp of the rat's lower incisors. The effect of prolonged etching time (60 seconds) was also assessed (Conditioner 36). The application of saline served as the untreated control. The technique of vitalmicroscopy was used on the first lower incisor of 40 (10-10 in each group) male Sprague-Dawley rats (weighing 350 +/- 8 g SE) to record the changes in vessel diameter prior to and at 5, 15, 30 and 60 minutes after the test materials were administered on the dentin. In the control rats, the vessel diameter was stable during the entire experiment. Acid conditioning as recommended by the manufacturers tended to cause vasodilatation, though these alterations were statistically not significant when compared to the control group (ANOVA, p > 0.05). After prolonged etching time (Conditioner 36, 60 seconds) significant vasoconstriction (-14.4 +/- 6.13; -10.59 +/- 4.2; -11.96 +/- 6.75; -5.49 +/- 5.78%) was observed (ANOVA, p < 0.05). In this group, stasis developed in pulpal blood circulation in 40% of rats (Cochran's-Q test, p < 0.05), gas-bubble formation was observed in 30% and the disappearance of the pulpal wall occurred in 20%. These results suggest that exposition time with acid is crucial to the pulpal microcirculation. That is, acid conditioning applied as indicated (for 15-20 seconds) onto a very thin layer of dentin only slightly affects the blood supply to the dental pulp; however, prolonged etching time (for 60 seconds) results in immediate failure of microcirculation in the dental pulp of rats.
    Operative Dentistry 01/2001; 26(3):248-52. · 1.31 Impact Factor
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    ABSTRACT: Materials employed in "adhesive filling technique" often lack informative instructions concerning the depth of cavities which require lining. Etching-materials directly placed on the dentin can adversely influence the pulp leading to changes in local microcirculation which can be an early sign of the pathological changes in the pulp. Therefore, it is worth examining the effect of these materials on the diameters of pulpal vessels. In the present study we examined wether acid etching (test1: 15 s and test2: 60 s) alters the blood circulation of the pulp lower incisors, by applying it directly onto a thin layer of pulpal wall (40-50 microns) without any liner, and following the instructions provided by the manufacturer. Twenty male Sprague-Dawley rats (weighing 330 +/- 51 g) and the technique of vitalmicroscopy was used for this investigation. The left lower incisors of the rats were prepared for vitalmicroscopy. Changes in vessel diameter were recorded prior to and 5, 15, 30 and 60 minutes after investigated materials or saline (control) were administered on dentin. In control and test1 group the vessel diameter was unchanged during the experiment. However, in group test2 an intense vasoconstriction was registered. There were significant (p > 0.05, ANOVA) differences in diameter changes between the control group and those treated with acid etching for 60s. Our results suggest that extended etching time may affect the circulatory system in the dental pulp, when applied onto very thin layer of dentin.
    Fogorvosi szemle 03/2000; 93(3):77-82.
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    ABSTRACT: No data are available on the direct acute vascular effect of dental bonding materials on the dental pulp. This study investigated the effects of the components of a composite resin-bonding system on pulpal vascular diameter. Three groups of 10 male Sprague-Dawley rats (weighing 330 +/- 51 g) were used for this investigation. The first lower incisor of the rats was prepared for vitalmicroscopy. Changes in vessel diameter were recorded prior to, and at 5, 15, 30 and 60 minutes after the bonding agents (with/without etching) or saline (control) were administered on dentin as recommended by the manufacturer. In control rats, the vessel diameter was elevated slightly (2.96 +/- 4.08%) during the whole experiment. However, in the presence of bonding materials, an enhancement of 12.58 +/- 7.1% without etching and 13.11 +/- 8.6% with acid etching was registered as the increase in vascular diameter. There were significant (p < 0.05) differences between the control group and those treated with bonding agent components. Results suggested that resin composite bonding agents applied to a thin layer of dentin have an acute vasodilating effect on the dental pulp. The clinical significance of this vascular alteration in the dental pulp requires further study.
    Operative Dentistry 01/2000; 25(5):418-23. · 1.31 Impact Factor
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    ABSTRACT: No data are available on the direct acute vascular effect of dental bond materials in the dental pulp. The purpose of the present study was to investigate the effect of composite resin bonding systems on the pulpal vascular diameter. Three groups of male Sprague-Dawley rats (weighing 300-490 g), each of 10 animals were used for this investigation. The left lower incisor of the rats was prepared for vitalmicroscopy. Changes in vessel diameter were recorded prior to; and 5, 15, 30, 60 minutes after the application of saline (control) or the bonding agents (test1: acetone containing--/Prime/Bond2.1, DeTrey/; test2: acetone free /Scotchbond Multi-Purpose Adhesive System, 3M/ bond material) on pulpal dentin as recommended by the manufacturer. In control rats, the vessel diameter was stable during the experiment. However, in the presence of bonding materials an enhancement was registered in vascular diameter (p < 0.05). The bond materials applied directly onto a very thin layer of dentin show acute vasodilating effect on the rat pulpal microvessels, but no stasis or prestasis has been detected, indicating a possible reversible effect. We could not show any statistical difference between the vasodilatation caused by the acetone containing and the acetone free bonding material.
    Fogorvosi szemle 06/1999; 92(5):151-6.
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    ABSTRACT: After crown preparation, exposed and untreated dentinal tubules can result in bacterial penetration into pulp. Treating the exposed dentin involves closing the tubules. Dentin sealers are often applied on a very thin dentin layer that covers the pulp chamber. In these cases, the sealers may have some effect on local micro-circulation through dentin. This study examined the acute effects of different dentin sealers on the vascular-diameter of pulpal vessels measured by vitalmicroscopic technique in rats. Gluma Desensitizer in Group 1 (n = 10), Seal & Protect with acid etching in Group 2 (n = 10) and Seal & Protect without acid etching in Group 3 (n = 10) were applied on a very thin layer of dentin in the left lower incisor of male Sprague-Dawley rats weighing 336 +/- 93SE/g. Saline served as the untreated control. After one-hour equilibration time, changes in vessel diameter were recorded with a digital camera connected to a microscope at baseline and at 5, 15, 30 and 60 minutes after the investigated materials were administered on dentin. The results were evaluated by ANOVA. In each group, diameter changes were averaged (compared to the baseline diameters) and standard errors of the mean were calculated for each examined time. The results suggest that Gluma Desensitizer caused the most severe pulpal vessel-diameter changes, followed by Seal & Protect with acid etching, while the least change was recorded in Seal & Protect without acid etching.
    Operative Dentistry 27(6):587-92. · 1.31 Impact Factor
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    ABSTRACT: The newly developed self-etching, self-priming all-in-one adhesives are appealing to clinicians because they are simple and efficient to use. These single-application bonding systems contain chemically active compounds that can alter pulpal blood circulation when applied to deep dentin surfaces. Since adequate microcirculation and oxygenation are the basic requirements for tissue survival, the aim of this study was to investigate the immediate vascular effect of a new self-etching adhesive, Prompt L-Pop/composite and compomer version/(test group). The technique of vitalmicroscopy was used to record the changes in vessel diameter of the first lower incisor of 20 (10-10 in each group) male Sprague-Dawley rats (weighing 315 +/- 74/SE/g) prior to, and at 5, 15, 30 and 60 minutes after the investigated materials were applied to dentin. The application of saline served as the untreated control. The systemic arterial pressure remained unchanged throughout the experiments both in the control (110 +/- 8 mmHg) and in test animals (114 +/- 4 mmHg). In control rats, the diameter of the vessels was stable during the experiment. In the presence of Prompt L-Pop, the diameters decreased significantly during the experimental period (5 minutes: -11.15 +/- 5.03%; 15 minutes: -14.66 +/- 7.71%; 30 minutes: -13.35 +/- 5.79%; 60 minutes: -11.82 +/- 5.63% p < 0.05 in each cases). In this group, stasis developed in pulpal circulation was 1 out of 10 rats. The results from the rat model used in this study suggest that Prompt L-Pop may result in compromised pulpal microcirculation.
    Operative Dentistry 29(1):75-9. · 1.31 Impact Factor
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    ABSTRACT: A patkánymetszőfog-pulpa vitálmikroszkópos modellje optimális az inicialis toxicitás okozta pulpális változások kimutatására. Kísérleteinkben a self-etch adhezívek hatására bekövetkező akut változásokat vizsgáltuk. A fogászati bondanyagok/adhezívek lokális applikációja reverzibilis és irreverzibilis változásokat okozhat. Az erősen savas (pH 0,8) adhezív veszélyeztette a pulpális mikrocirkulációt, míg a közepesen erős savhatású önsavazó bondrendszer (pH 1,5) csak reverzibilis dilatációt okozott. A NO-szintáz blokkolók (L-NAME) lokalis hatását eddig nem vizsgálták. Vizsgálatainkban nyugalmi feltételek mellett, illetve bondanyag applikációját követően közvetlenül tanulmányoztuk hatását patkányfogak pulpális arterioláinak belső átmérőjére. Az L-NAME redukálta a pulpális arteriolák érátmérőjét mind nyugalmi, mind bondanyag okozta hyperaemia esetén. Ezek az adatok arra utalnak, hogy a nitorgénmonoxidnak meghatározó szerepe szerepe lehet mind a bondanyagok okozta akut vasodilatatióban, mind a basalis arteriális tónus fenntartásában. | The vitalmicroscopic model of the rat first incisor's pulp is an optimal technique for demonstrating the initial toxicity caused pulpal changes. In our study we investigated the acut effect of self-etch adhesives. The local application of dental bondmaterials/adhesives could cause reversible and irrevesible changes. The strong acidic adhesive (pH 0,8) compromised the pulpal microcirculation, while the 'intermedier strong' (pH 1,5) caused reversible dilatation. The blockers of NO synthase had never been investigated before. In our experiment we studied the effect of NOS inhibitor on basal condition and after bond material application using vitalmicroscopic method. L-NAME reduced the diameter of the pulpal arteriole both in basal and after bond material-induced hyperaemic conditions. Our data suggest that the local formation of NO may have a significant role in the acute vasodilatation induced by bond material application and also in maintenance of basal pulpal arteriolar tone.
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    ABSTRACT: Vazoaktív mediátorok keringésszabályozó szerepét tanulmányoztuk ép és gyulladt fogínyben patkányban. Humán gingiván a fogorvosi beavatkozások hatását vizsgáltuk. Adataink szerint patkány marginális gingiva erekben érszűkítő adrenerg alfa1, alfa2, valamint endotheliális ETA receptorok találhatók. A vaszkuláris endotheliális növekedési faktor (VEGF) a gingiva bazális keringésszabályozásában nem vesz részt, de azt az íny VEGF-2 érreceptorain keresztül befolyásolhatja. Primer neurogén gyulladás szisztémás antiinflammációs hatása a gingivában is leírható. E hatásban a nitrogénoxid szerepe valószínű. Megvizsgáltuk a gyomornedvből izolált gasztrikus pentadekapeptid BPC157 hatását ép, ill. gyulladt fogínyre. BPC157 vazokonstriktor, kísérletes parodontitisben gyulladáscsökkentő. Az alveoláris csontállományra protektív hatású. Az ínybarázda (gingivális sulcus) kemomechanikai tágítása a fogorvoslásban alkalmazott eljárás. Vizsgálataink szerint a használatos adrenalin koncentrációval átitatott tágító fonal a sulcusfolyadék elválasztást nem befolyásolja. Barázdatágításra a 0,1 %-os adrenalin oldat a leghatékonyabb. Bölcsességfogak pulpájából, ill. parodontiumából tenyésztéssel sejtkultúrát nyertünk, melyben vizsgáltuk a fogászati anyagok sejtproliferációra gyakorolt hatását. A pozitív STRO-1 immunreaktivitás sejtkultúránkban mesenhymalis őssejtek jelenlétére utal. A hemostatikumok, ill. retrakciós szerek klinikumban használt koncentrációi toxikusak. Emdogain a sejtproliferációt fokozta. | The role of vasoactive mediators has been studied in blood flow regulation to the sound/inflamed rat gingiva. The gingival effects of dental treatment were also detected in human. According to our data vasoconstrictor alpha1, alpha2 and endothelial ETA receptors localize in the blood vessels of the marginal gingva. Although the vascular endothelial growth factor (VEGF) does not participate in the basal flow regulation to the gingiva, exogenous VEGF evokes an enhanced gingival blood perfusion by the means of local VEGF2 receptors. The systemic anti-inflammatory effect of primary neurogenic inflammation can be observed also in the gingiva. Nitric oxide is probably involved in this process. The effect of gastric juice pentadecapeptide BPC157 on the sound/inflamed gingiva was also studied. BPC157 induces vasoconstriction and decreases inflammation in experimental periodontitis. The chemo-mechanical exposure of the gingival sulcus is a procedure commonly used in dentistry. Among the concentrations of epinephrine we used 0.1% was the most effective one, without any effect on crevicular fluid production. In order to study the effect of dental materials on the cell proliferation tissue culture was gained using the cells of dental pulp and connecting periodontium of wisdom teeth. The positive STRO-1 immunreactivity observed in our tissue culture refers to the presence of mesenchymal stemm cells. Clinically used concentrations of hemostatic and vasoconstrictor retraction solutions are toxic for the cultured cells. Emdogain shows a cellproliferative effect.