Biomedical subjects

A Fazekas

Publications and source records attributed to A Fazekas.

At least 55 records · Page 3Linked to original sources

PubMed1995

[Metal-based esthetic inlays].

The aesthetic appearance and marginal accuracy of porcelain fused to metal inlays/onlays have been evaluated in this study. The metal frameworks of the restorations were fabricated by casting or by galvanic techniques. Both the gold collar and the insufficient thickness of covering porcelain influenced the aesthetic features of inlays negatively. The good aesthetic appearance achieved in case of onlays was independent of manufacturing procedures. Inlays/onlays accomplished by galvanic technique showed a better marginal fitting as compared to that of cast ones.

Adult↗

PubMed1994

Effect of nitric oxide inhibition on capsaicin-elicited vasodilation in the rat oral circulation.

The effects of local application of capsaicin on the vascular conductance of the oral structures (upper gingiva, lower gingiva, tongue, right and left submandibular glands) were studied with and without pretreatment with NG-nitro-L-arginine methyl ester (L-NAME), a potent inhibitor of nitric oxide formation in rats. Alterations in tissue blood flow were measured by laser-Doppler-flowmetry; systemic blood pressure was monitored continuously during the experiments. Local application of increasing concentrations of capsaicin (1.0; 3.33; 10.0; 33.3 mM; in a volume of 5 microliters) resulted in a dose-dependent increase in the vascular conductance of all tissues investigated. There was a significant correlation between the values obtained for vascular conductance in the right and the left submandibular glands. Bolus intravenous injection of L-NAME (10 mg kg-1) elevated the mean systemic blood pressure significantly, by about 20%, with a rapid onset. This increase persisted until the end of the experiment. The augmentation of vascular conductance elicited by 10.0 mM capsaicin, locally administered, was significantly diminished in animals pretreated with L-NAME in all tissues tested. The results indicate that nitric oxide formation plays a significant role in the enhancement of vascular conductance produced in rat oral structures by local capsaicin administration.

Afferent Pathways↗

PubMed1994

Neurogenic component in ligature-induced periodontitis in the rat.

Effect of ligation on the vascular permeability in the gingiva and alveolar mucosa encircling the mandibular left 1st molar was studied in rats with and without capsaicin pretreatment. Vascular permeability was assessed by the Evans blue extravasation. Ligation caused a significant augmentation in vascular permeability of the gingivomucosal tissue at day 8 (right: 18.14 +/- 1.68 micrograms g-1; left (ligature): 38.21 +/- 2.43 micrograms g-1, n = 8, p < 0.001) and at day 14 (right: 20.31 +/- 1.71 micrograms g-1: left (ligature): 36.98 +/- 2.73 micrograms g-1, n = 8, p < 0.001). 4 days after ligation, no difference could be observed in vascular permeability in the oral mucosa of the ligated side (left: 23.14 +/- 1.21 micrograms g-1) as compared to the side without ligature (right: 23.5 +/- 1.45 micrograms g-1, n = 8, NS). There was no elevation of vascular permeability of gingivomuscosal tissue around the ligation in rats pretreated with capsaicin either in newborn age (right: 23.92 +/- 1.76 micrograms g-1; left (ligature): 23.51 +/- 2.16 micrograms g-1, n = 8, NS) or in adult age (right: 20.61 +/- 1.62 micrograms g-1; left (ligature): 20.85 +/- 1.07 micrograms g-1, n = 8, NS). Light microscopical studies of oral mucosa revealed, that 8 and 14 days after the ligature placed around the mandibular left 1st molar of the rat, there resulted an accumulation of inflammatory cells in the connective tissue.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗

PubMed1994

[Alveolar bone replacement by implantation of Ossynth and Ossnativ hydroxy apatite ceramics].

Natural and synthetic HA-granulate (made by SZIKKTI Budapest) were implanted to 91 patients by the authors with the aim of bone replacement. Follow up controls proved that the biomaterial has been incorporated without clinical symptoms and complaints in 87 percent. Biopsies taken from replacement site showed that the HAK isolated from natural substance could be incorporated into the calcified tissue and it is also able to help the formation of the new bone.

Adult↗

PubMed1994

[Hygienic considerations of fixed bridges].

The purpose of the present study was to examine whether the pontics form in the everyday practice suits the hygienic requirements. 74 bridges in 30 individuals were examined with clinical methods. 58 per cent of the restaurations had a concave surface towards the alveolar ridge. More than the half of the bridges were resting on the underlying mucosa. The patients didn't know the special instruments, that are necessary to clean the pontics and they weren't taught how to do it. In consequence of these facts only 7 pontics were found without plaque accumulation on their gingival surface. Methods are offered by the authors to improve the conditions of the better oral hygiene of the patients with fixed partial dentures.

Dental Devices, Home Care↗

PubMed1993

Role of substance P (SP) in development of symptoms of neurogenic inflammation in the oral mucosa of the rat.

In the present series of investigations we first studied the local effects of exogenous substance P (SP) on the hallmarks of neurogenic inflammation, i.e. vascular permeability and blood flow, in the oral mucosa of the rat. Pretreatment with capsaicin was shown to attenuate the symptoms of neurogenic inflammation; therefore, the distribution of nerve fibers displaying substance P-like immunoreactivity (SP-IR) in the mandibular mucosa was also assessed in control rats and in animals pretreated with capsaicin both neonatally and in adulthood using immunohistochemical techniques. The application of SP at a dose of 7.5 nmol resulted in an almost 70% increase of vascular permeability (NS) and the administration of a four-fold higher dose (30 nmol) produced about 150% increase in Evans blue extravasation compared with control values (p < 0.05). A similar increase (ca 146%) in vascular permeability was observed in response to 45 nmol SP solution (p < 0.05). While the 7.5 nmol SP-solution failed to affect blood flow, the 30 nmol SP significantly increased it by ca. 38% (p < 0.05). The administration of the 45 nmol SP solution resulted in a similar enhancement of blood flow (43%, p < 0.05). Capsaicin pretreatment performed either neonatally or in adulthood has reduced the number of SP-immunoreactive fibers in the oral mucosa. Our functional results suggest that SP may have a role in the experimentally-induced neurogenic inflammation of the oral mucosa in the rat. This is also supported by our finding that capsaicin pretreatment, known to decrease the number of SP-immunoreactive fibers in these tissues, reduced the symptoms of neurogenic inflammation.

Analysis of Variance↗

PubMed1993

[Improvement of the stability of the total lower prosthesis by vestibuloplasty].

An up-to-date method of vestibuloplasty is shown by a case report. The flap raised from the cheek is suitable to cover the surface of the anterior alveolar process made free during the deepening of the lower vestibular fold. The recipient and donor areas are both within the oral cavity, thus the procedure is simple and the patients can bear it without difficulty. Due to the new anatomical situation the functional stability of complete dentures is considerably increased.

Cheek↗

PubMed1992

Neurogenic inflammation and the oral mucosa.

Since the rôle of neurogenic inflammation in various pathological conditions is well-established, we presume that it also has great importance in the development of several inflammatory processes in the oral mucosa. In the course of experimentally-induced neurogenic inflammation of the oral mucosa in rats, vasodilation and plasma extravasation occur in the area supplied by unmyelinated capsaicin-sensitive fibres. Upon activating these fibres in the oral mucosa, mediators such as histamine, substance P (SP) and calcitonin gene related peptide (CGRP) are released from the peripheral terminals of afferent nerves causing characteristic symptoms of neurogenic inflammation. By histochemical techniques, SP- and CGRP-immunoreactive fibres have occurred in the area of the rat oral mucosa stimulated mostly in the free and attached gingiva around the molar teeth in the lower jaw. Capsaicin pretreatment performed neonatally or at adult age causes a loss of SP-immunoreactive fibres and prevents the vasodilatory responses, as well as the increase in vascular permeability elicited by the antidromic stimulation of the inferior alveolar nerve. As the transection of inferior alveolar nerve decreased the extravasation of Evans blue on the ipsilateral side and did not affect the capsaicin-induced enhancement in blood flow, we suggest that the two symptoms of the inflammation, i.e., the increased vascular permeability and decreased vascular resistance, should be produced by different mechanisms. The results of all the morphological and functional studies seem to confirm the possibility that there is an important neurogenic component of the inflammatory alterations caused by different mechanical and chemical stimuli in the oral mucosa.

Capsaicin↗

PubMed1992

Effect of substance P administration on vascular permeability in the rat dental pulp and submandibular gland.

The effects of substance P (SP) administration on vascular permeability were studied in the dental pulp (DP) of upper and lower incisors and in the submandibular gland (SMG) of male rats. Vascular permeability was assessed by means of extravasation of Evans blue dye. SP was diluted in 0.5% bovine serum albumin (BSE) and infused into the left common carotid artery. Separate groups of animals receive chloropyramine, an H1 histamine receptor antagonist (10 mg kg-1 i.v.) or indomethacin, a prostaglandin synthesis inhibitor (4 mg kg-1 i.v.) prior to SP infusions. Infusion of SP for 5 min increased plasma extravasation both in DP and SMG, with a threshold of about 30 pmol min-1 and 74 pmol min-1, respectively. Enhanced salivary secretion was also observed. Although the administration of 74 pmol min-1 of SP significantly lowered the systemic blood pressure, experimental hypotension elicited by haemorrhage did not influence vascular permeability in either organ tested. After chloropyramine administration the SP effect on vascular permeability in both DP and SMG was abolished. Indomethacin pretreatment failed to prevent the permeability-enhancing action of SP. Our results suggest that substance P increases both pulpal and glandular plasma extravasation in the rat indirectly, via the release of histamine and the activation of H1 histamine receptors.

Animals↗

PubMed1992

[The fundamental method of preventive prosthodontics: complex rehabilitation of the masticatory organ].

The most effective prosthetic prophlaxis could be the prevention of causes leading to tooth extractions. As now the caries and periodontal preventions are not efficient enough we are obligated to deal with the consequences of tooth loss. Even the loss of a single tooth might cause disfunctions in the masticatory system. Besides the well known consequences, like diminished masticatory, phonetic functions and esthetical problems we have to face to the consequences related to morphological changes in the dentition leading to difficulties in prosthodontic treatment planning and tooth preparation. So, the most important step in prosthodontic prophylaxis is the early replacement of the lost tooth. The early prosthetic reconstruction can only be prophylactic if it does not interfere with the normal hygienic procedures in the oral cavity. Consequently it is very important to consider all the possible factors affecting the oral hygiene during our prosthetic treatment planning. We should also consider the basic gnatological principles in designing the occlusal surface of crowns and pontics to avoid any traumatic occlusal forces related to our would be reconstructions.

Humans↗

PubMed1991

Effect of denervation on the neurogenic inflammation of the rat mandibular mucosa.

Effects of local exposure to capsaicin on the vascular permeability and blood flow were studied in the rat oral mucosa at days 2 and 14 after the unilateral transection of the inferior alveolar nerve (IAN). The distribution of nerve fibers displaying substance P (SP) and calcitonin gene-related peptide (CGRP) immunoreactivity (IR) in the mandibular mucosa was also assessed. While the capsaicin-induced augmentation in vascular permeability was about 50% (P less than 0.05) higher on the intact side (at both days 2 and 14) than on the denervated side, no difference in blood flow elevation was seen between the two sides. Transection of IAN caused only a slight reduction in the density of SP- and CGRP-IR fibers in the mucosa. It is concluded that in addition to the IAN fibers the mandibular mucosa examined also seems to be supplied by other sensory fibers. The presence of accessory trigeminal branches was also supported by immunohistochemical studies.

Animals↗

PubMed1991

Role of histamine in the development of neurogenic inflammation of rat oral mucosa.

The mechanism of development of neurogenic inflammatory reaction induced by the topical application of capsaicin was studied in the oral mucosa of rats with or without histamine antagonist pretreatment. The existence of a cholinergic component of the vasodilation was investigated using a muscarinic receptor antagonist. Results indicated that the neurogenic inflammatory increases in vascular permeability and blood flow are mediated in part by H1-receptors, H2-receptors and cholinergic pathways are apparently not activated in these processes.

Animals↗

PubMed1991

Effects of angiotensin II on blood flow in rat submandibular gland.

The effect of angiotensin II (Ang II) was studied on blood flow in the submandibular gland and tongue in male rats. Blood flow changes were determined with laser Doppler flowmetry and Ang II was infused into the common carotid artery before and after i.v. doses (18 nmol kg-1) of the angiotensin II antagonist saralasin. Angiotensin II (10-60 pmol min-1) dose-dependently increased blood pressure and tongue blood flow, whereas glandular blood flow decreased at all of the doses used. After saralasin administration the angiotensin II effects on blood pressure, tongue and glandular blood flow were significantly diminished (glandular blood flow reduction was diminished from 29%-3%, P less than 0.005, n = 9). However, the responsiveness of these 3 parameters to local infusions with noradrenaline (0.75-3.0 pmol min-1) was unaffected by saralasin. The dose of saralasin used in the present study did not affect any of the parameters on it's own. Our results show that vascular receptors sensitive to angiotensin II operate in the submandibular gland but not in the tongue.

Angiotensin II↗

PubMed1991

[The role of histamine in neurogenic inflammations of the mouth mucosa in rats].

The effect mechanism of neurogen inflammation incited by local capsaicin irritation was examined by the authors in the oral soft tissue of rats subsequent to antihistamin pretreatment. Furthermore, with the aid of muscarin blocking receptor also the parasympathetic component of the vasodilatation was examined. On basis of their results it was established that the vein-wall-permeability and microcircular changes observed in the course of the neurogen inflammation of the oral soft tissue partly expanded by the histamin through the H1-receptors. The H2-receptors as well as the parasympathetic fibers do not become activated in the process.

Animals↗

PubMed1991

[Questions of principle and practice concerning the use of Diakor aluminum oxide in bioceramical oral endosseous implantation. III. Surgical intervention].

The osseointegration desired in interest of lasting success may be obtained but by means of an aseptic atraumatic operational technique which ensures the primary stability of the implant. It is pointed out that the infection free wound healing plays a decisive role in the lasting stability of the implant also the surgical planning and the method of avoiding complications are described.

Aluminum Oxide↗

PubMed1991

[The effect of the transsection of the inferior alveolar nerve on neurogenic inflammation of the mouth mucosa. II. Immunohistochemical studies].

The distribution of nerve fibers displaying calcitonin gene-related peptide (CGRP) immunoreactivity in the mandibular mucosa was studied in control rats, in rats after unilateral transection of the inferior alveolar nerve (IAN), and in animals following cervical sympathetic denervation. According to the results, the transection of the peripheral branch of the IAN has no effect on the distribution of the CGRP immunoreactive nerves.

Animals↗

PubMed1991

[The effect of transsection of the inferior alveolar nerve on neurogenic inflammation of the oral mucosa. I. Functional studies].

Vascular effects of local capsaicin treatment has been studied on the 2nd and 14th days subsequent to unilateral inferior alveolar nerve (IAN) transection in the oral mucosa of rats. The results suggest, that the symptoms of neurogenic inflammation were influenced by the transection of IAN in a different way. The reason of that is the different mechanism in the development of the symptoms and/or the different compensatory capacity of the accessorial nerves.

Animals↗

PubMed1990

[Gardner syndrome].

A syndrome going with skin-bone signs and precancerous gastrointestinal polyposis is presented. Interest of our case is given by the extension of polyposis onto the whole digestive canal, early appearances of abdominal signs accompanying polyposis, and as a new symptom polycystic lung and extended superficial naevus lipomatosus.

Adult↗