Biomedical subjects

Slavoljub Zivković

Publications and source records attributed to Slavoljub Zivković.

5 recordsLinked to original sources

PubMed2006

Central vasopressin V(1a) and V(1b) receptors modulate the cardiovascular response to air-jet stress in conscious rats.

This study investigates the contribution of central vasopressin receptors in the modulation of systolic arterial pressure (SAP) and heart rate (HR) response to air-jet stress in conscious Wistar rats equipped with a femoral arterial catheter and intracerebroventricular cannula using novel non-peptide and selective vasopressin V(1a) (SR49059) and V(1b) (SSR149415) antagonists. The effects of stress on SAP and HR were evaluated by measuring the maximal response to stress, the latency of the maximal response, the duration of the recovery period, and the increase in the low frequency (LF) short-term variability component. Stress induced a parallel and almost immediate increase in both SAP and HR, followed by enhanced LF SAP variability in the recovery period. Pretreatment of rats with V(1a) antagonist did not affect the maximal increase or the latency of SAP and HR response to acute stress, but shortened the recovery period of SAP and HR and prevented the increase in LF SAP. The V(1b) antagonist reduced the maximal increase in SAP without affecting HR and their latencies, shortened the recovery period of SAP and inhibited the increase in LF SAP variability. These results indicate that both central V(1a) and V(1b) receptors mediate cardiovascular changes induced by air-jet stress in conscious rats.

Adaptation, Physiological↗

PubMedDate not supplied

[Root canal preparation techniques using nickel-titanium rotary instruments].

INTRODUCTION: The main purpose of endodontic treatment is to clean the root canal system, eliminate the infected and toxic contents, and shape it in order to get a tridimensional obturation. The aim of this paper is to inform dental practitioners about crown-down technques for root canal preparation using nickel-titanium rotary instruments. ROOT CANAL PREPARATION: Today most endodontists believe that root canal preparation is more efficious, cleaning and shaping are better, if pre-enlargement of coronal two thirds is performed first, and shaping of the apical part later. Machine driven rotary instruments provide much quicker and better root canal preparation. CONCLUSION: Contemporary endodontic rotary files vary in regard to their taper, cutting blades, guiding tip and material they are made of. The usage of rotary nickel-titanium files adds a new quality to root canal preparation.

Dental Alloys↗

PubMedDate not supplied

[Frequency of the external resorptions of tooth roots].

Root resorptions present a significant problem in endodontic therapy of the affected teeth and in dentistry in general. The objective of this study was to analyze, based on epidemiological and statistical research, the frequency of clinical incidence of pathological root resorptions in everyday practice related to localization, type of tooth, age and sex of patients. Radiographic documentation of patients treated from 1997 till 2002 at the Department of Conservative Dentistry and Endodontics, Faculty of Stomatology in Belgrade, was used as baseline for this study. Retroalveolar radiographs of teeth with visible signs of resorptions were singled out from 15654 patients' clinical records used for this study. The external resorptions were shown as radiolucent areas localized on various outer root surfaces, followed by significant or less significant resorption of lamina dura and alveolar bone. Out of all teeth analyzed in this study, 594 (3.79%) showed some kind of resorption. The external resorptions were found to be more present in the upper jaw (55.10%) and molars (50.30%) than in the lower jaw (44.90%) and single root teeth (49.70%), but in both cases without significant statistical differences. The most frequent localization of resorptions was root apex (82.44%). In regard to age, the most frequent resorptions were recorded in patients aged between 21 and 30 years (28.40%), and the lowest incidence was found in the youngest population (5.51%). The results also showed that resorptions were more frequent among the female population (59.04%) than among the male population (40.96%). Based on these results, we may conclude that the external root resorptions are not a frequent clinical phenomenon. Proper and early diagnostics of such tissue pathology is one of the basic prerequisites for successful endodontic therapy of the affected root.

Adolescent↗

PubMedDate not supplied

[Localisation of main and ancillary foramina within the mesial and distal roots of the first lower molars].

INTRODUCTION: Understanding the morphology of the root canal system, and especially its apical third, represents the basic precondition for the successful treatment of diseased pulp and the apical endodontium. AIM: The aim of this study was to precisely locate the main and ancillary foramina in the mesial and distal first lower molars. METHOD: One hundred extracted first lower molars, originating from persons of both sexes and three different age groups, were used in the study. RESULTS: The analysis of the sampled molars' apical third was carried out using a binocular magnifier and a digital X-ray scanner (Trophy). The results showed that the main mesial and distal root foramina were located mostly on the distal surface. The ancillary mesial and distal root foramina were located at the lingual end, in most cases. Statistical analysis demonstrated the congruence of results achieved using the binocular magnifier and digital x-ray in 100% of cases if the main foramen is located on the very top of the mesial root (chi2 = 17.23; p < 0.001), and in 92.9% of cases if the main foramen is localised on the very top of the distal root of the first lower molar (chi2 = 12.07; p < 0.001). CONCLUSION: The most common localisation of the main foramina for all age categories and in both mesial and distal roots is on the distal surface of the root. The greatest number of ancillary foramina was observed in the youngest age category, while they were localised most often on the lingual side of the mesial and distal root.

Adolescent↗

PubMedDate not supplied

[Computerized occlusal analysis in bruxism].

INTRODUCTION: Sleep bruxism as nocturnal parafunction, also known as tooth grinding, is the most common parasomnia (sleep disorder). Most tooth grinding occurs during rapid eye movement - REM sleep. Sleep bruxism is an oral habit characterized by rhythmic activity of the masticatory muscles (m. masseter) that causes forced contact between dental surfaces during sleep. Sleep bruxism has been associated with craniomandibular disorders including temporomandibular joint discomfort, pulpalgia, premature loss of teeth due to excessive attrition and mobility, headache, muscle ache, sleep interruption of an individual and problems with removable and fixed denture. Basically, two groups of etiological factors can be distinguished, viz., peripheral (occlusal) factors and central (pathophysiological and psychological) factors. The role of occlusion (occlusal discrepancies) as the causative factor is not enough mentioned in relation to bruxism. OBJECTIVE: The main objective of this paper was to evaluate the connection between occlusal factors and nocturnal parafunctional activities (occlusal disharmonies and bruxism). METHOD: Two groups were formed- experimental of 15 persons with signs and symptoms of nocturnal parafunctional activity of mandible (mean age 26.6 years) and control of 42 persons with no signs and symptoms of bruxism (mean age 26.3 yrs.). The computerized occlusal analyses were performed using the T-Scan II system (Tekscan, Boston, USA). 2D occlusograms were analyzed showing the occlusal force, the center of the occlusal force with the trajectory and the number of antagonistic tooth contacts. RESULTS: Statistically significant difference of force distribution was found between the left and the right side of the arch (L%-R%) (t=2.773; p<0.02) in the group with bruxism. The difference of the centre of occlusal force - COF trajectory between the experimental and control group was not significant, but the trajectory of COF was longer in the group of bruxists (67.3+24.4mm). In addition, the significant difference of COF position in relation to the center of the elliptic fields was not found in bruxists (chi-squared=1.63; p> 0.05), but obtained results directly revealed uneven distribution of the occlusal forces which caused the excessive attrition and mobility of tooth. CONCLUSION: Our study failed to find direct correlation between occlusal factors and bruxism, so they are basically contributing factors.

Adult↗