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Milán Gyurkovics,
Zsolt Lohinai, Adrienne Gyorfi,
Iván Iványi,
Ibolya Süveges,
Mária Kónya,
Csaba Bodor,
Andrea D Székely,
Elek Dinya,
Arpád Fazekas,
László Rosivall
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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. · 2.60 Impact Factor
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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: Accurate working length (WL) determination is a crucial part of successful root canal therapy. Working length is the distance from the coronal reference plane to the apical constriction. The apical constriction, also referred to as cementodentinal junction, represents the transition between the pulpal and the periodontal tissues. It is widely accepted that canal preparation and filling should be terminated at that point. However, the location and form of the apical constriction are variable and not always detectable. Moreover, the available clinical methods used for WL measurements are also inaccurate. At present two methods are recommended in dental practice for determination of WL: radiographic technique, and by the means of electronic apex locators. Advantages and disadvantages of the two methods are discussed in this paper.
Fogorvosi szemle 09/2006; 99(4):153-9.
