Summary The aim of this study was to investigate the influence of different light curing modes on the depth of cure of the composite resin. The metal block with formed round holes served as a mold for the placement of the composite resin. The composite resin was cured with Penguin DB-685 lamp with four optional working modes: strong, low, gradually strong, and flashing. Unpolymerized part of the composite specimen was removed by scraping with a plastic spatula, and then each specimen was placed into the capsule with 1 ml of ethanol alcohol and mixed for 20 s in amalgamator. The length of the remaining composite specimen was measured with the digital caliper with a precision of 0.01 mm. The measured values were divided by 2 (according to ISO 4049 standard) and then statistically processed. Based on the measured lengths of the polymerized part of the composite specimens, the lowest average value of the depth of cure (2.75 ± 0.08 mm) was determined after polymerization with the low mode and the highest value was obtained (2.98 ± 0.08 mm) with strong polymerization mode. Statistically significant difference (p < 0.05) was determined between low polymerization mode and all other modes (strong, gradually strong and flashing mode). The observed statistically significant differences are not clinically important because all curing modes provided the necessary depth of cure, which is in accordance with the clinical recommendation of 2 mm thick composite layer.

The aim of this study was to evaluate the influence of composite resin type and light curing source on the microleakage of composite restorations. The material consisted of 48 Class V cavities prepared on 24 extracted human premolars. The cavities were divided into two groups (n = 24), depending on the applied composite resin (flowable Filtek Ultimate vs universal Valux Plus). The division into two subgroups (n = 12) was dependent on the used light curing source (halogen ESPE Elipar Highlight vs LED Twinlex Blue Lex). The evaluation of composite restorations microleakage was performed using the dye penetration method with 1% methylene blue solution. The dye penetration was assessed after the longitudinal cut of the teeth. It was ranked according to the scale of 0-4. The highest microleakage score was in the group with flowable composite and halogen light (2.92 ± 1.16), and the lowest in the group with universal composite and LED light (0.75 ± 1.36). Mann-Whitney test showed that there was a statistically significant difference in the composite restorations microleakage between the following groups: flowable/halogen vs universal/halogen, flowable/LED vs universal/LED and flowable/halogen vs universal/ LED (p < 0.05). It can be concluded that the influence of composite resin type on composite restorations microleakage is higher than of the light curing source.

The accuracy of apex locators is very important for the correct working length determination of the root canal, and thus for successful endodontic treatment. The aim of this study was to compare in vitro the accuracy of iPex II (the fourth generation) and Adaptive (the sixth generation) apex locators. The material consisted of 28 root canals (16 premolars). The working length of all root canals was determined first by entering K-file #15 up to the apical foramen, what was checked by visual tracking of the top of the file. The fixed working length was then measured with a digital caliper and the obtained values were used to control measured canal lengths in two experimental groups. The teeth were immersed in the alginate before electronic measurements in order to simulate the clinical situation. In the first experimental group, the working length of the root canals was measured with iPex II, and in the second with Adaptive apex locator. All measurements were performed up to the apical foramen in the dry canal. The results of One-way ANOVA showed that there was not statistically significant difference between examined experimental groups (p > 0.05). The biggest difference existed in comparison the values of Adaptive apex locator and the control group, and the lowest in comparison iPex II and Adaptive apex locators. It can be concluded that both apex locators are accurate enough for clinical practice although they belong to different generations.

Sažetak: Cilj rada je bio da se proceni prisustvo polnog dimorfizma i ispita uticaj meziodistalnog promera gornjih stalnih sekutića i očnjaka na određivanje pola. Ispitivanjem je obuhvaćeno 40 osoba (20 osoba muškog i 20 osoba ženskog pola). Ispitanicima su otisnute gornje vilice u alginatu i na osnovu otisaka su izlivani studijski modeli. Ukupno je mereno 240 zuba. Merenja su izvršena digitalnim nonijusom (Asimeto model 307-06-1, Kanada) sa preciznošću od 0,01mm. Meren je meziodistalni promer gornjih sekutića i očnjaka, od mezijalne do distalne kontaktne tačke, u najvećoj interproksimalnoj razdaljini, pri čemu su kraci mernog istrumenta postavljani paralelno sa uzdužnom osom zuba u predelu kontaktnih tačaka. Meziodistalni promeri gornjih stalnih sekutića i očnjaka su pokazali signifikantne razlike između polova. Najveći procenat polnog dimorfizma utvrđen je kod gornjeg očnjaka, a najmanji kod gornjeg lateralnog sekutića. Merenje odontometrijskih parametara može biti korišćeno u forenzičkoj praksi kao pomoćna metoda u identifikaciji pola, a kao osnovna metoda kada su zubi jedini dokaz u istrazi.

The toxic effect of microwave radiation (MW) causes the change in the metabolism of polyamines. Polyamines (spermine and spermidine) and their precursor, diamin putrescine, are non-protein nitrogenous bases and they are essential to the function of the cell. Spermine and spermidine are catabolized by the enzyme polyamine oxidase (PAO), while the catabolism of putrescine is under the effect of the diamine oxidase (DAO). The neurohormon melatonin participates in maintaining the normal function of the immune system. The aim of this study was to analyze the effect of melatonin on the catabolism of polyamines in the rat thymus, following the chronic microwave exposure. Wistar rats were divided into four experimental groups: 1) control group, 2) Mel-the animals which were given melatonin daily (2mg/kg), 3) MW-the animals which were exposed to MW (4h daily), 4) the animals which were exposed to MW and were given melatonin daily. The animals were sacrificed after 20, 40 and 60 days of the experiment. There was an increase in the PAO activity and decrease in the DAO activity (already after 20 days) in comparison to the control in the thymus of rats exposed to microwave radiation. There was also a statistically significant positive correlation (p < 0.05) between malondialdhehyde levels and the activity of PAO during the MW exposure. A significant decrease in both PAO and DAO activity was found in the thymus of animals exposed to MW and treated with melatonin, in comparison to the irradiated animals not treated with melatonin.