Anatomical features of the palatal root canal in maxillary first molars and their influence on endodontic procedure

Introduction: More detailed acquaintance with specialist endodontic literature and treating complicated endodontic cases have revealed that the palatal root canal in maxillary first molars has different features from generally accepted simplicity. Aim: The aim of this study was to investigate the number, orientation and shape of the curvature of the palatal root canal in maxillary first molars, characteristics that may have great influence on the procedure and outcome of endodontic therapy. Materials and methods: Material consisted of 100 left and 100 right extracted human first maxillary molars. Extended access cavity was prepared, and canal orifices were detected using an endodontic probe. K-flex file no 15 or 20 was then introduced into the palatal root canal until the tip appeared at the apical foramen. The tooth was radiographed from buccal-oral (clinical) and mesial-distal (proximal) aspect under standardized conditions. On magnified images, the number and character of canal, orientation and shape of the curvature were determined. Results: One palatal root canal was found in each of 200 teeth. From the clinical projection, 60% of the palatal canals appeared curved and from the proximal 93.5% (p<0.05). Out of 120 curved canals from the clinical aspect, 66.7% were oriented distally and 33.3% mesially. From the proximal projection, of 187 curved canals 68,4% were oriented buccally, and 31,6% palatally. From the clinical projection, 49.2% were C-shaped, and 32.5 % with the J-shaped curvature. Only 18.3% of the palatal canals were with the S-shaped curvature (p<0.05). Conclusions: Upon presented results, practitioners may predict with high significance the character, orientation and curvature shape of the palatal root canal in maxillary first molars in the buccal-oral dimension which is not visible on clinical radiographs and, therefore, perform more successful endodontic treatment

Sexual differences in size and shape of the Mosor rock lizard [Dinarolacerta mosorensis (Kolombatović, 1886)] (squamata: lacertidae): A case study of the Lovćen mountain population (Montenegro)

Sexual differences in size and shape of the Mosor rock lizard, Dinarolacerta mosorensis (Kolombatović, 1886), from Lovćen Mountain (Montenegro) were examined on the basis of the intersex variation pattern of nine morphometric, eight pholidotic, and four qualitative traits. Sexual dimorphism was apparent for all morphometric characters except snout-vent length, while scalation and dorsal pattern exhibited small differences between sexes. The value of the sexual size difference (SSD) index based on snout-vent length was 1.028. The sex-specific allometric slopes for head dimensions and interlimb distance significantly diverged. Head dimensions, especially head height, showed strong positive allometry in males, while interlimb distance was the only character which showed positive allometry in females. Generally, males had significantly greater body size than females. This was true of all body measurements except interlimb distance. The influence of sexual and natural selection on the examined traits is discussed

Uticaj kompozita s malom kontrakcijom i konvencionalnih kompozita na postoperacionu osetljivost zuba

Introduction. Postoperative sensitivity in restorative dentistry can be related to preparation trauma, dentin adhesives' ability to seal open dentinal tubules, deformation of restorations under occlusal stresses and microleakage. Objective. The study assessed possible reduction in postoperative sensitivity with low shrinkage compared to conventional composites using different bonding agents and the influence of the operator skill on the incidence of postoperative sensitivity. Methods. Nine hundred and sixty permanent premolars and molars with primary carious lesions from patients 21 to 40 years old were used. Cavities 2 to 3 mm deep and with margins in enamel were prepared by four operators. Two operators had five years (A and B) and two had over 20 years (C and D) of clinical experience. Teeth were divided into eight groups each contained 120 restorations: (1) Els®+James-2 (original formula), (2) Els®+James-2 (new formula), (3) Els®+Excite, (4) InTenSe®+James-2 (original formula), (5) InTenSe®+James-2 (new formula), (6) InTenSe®+Excite, (7) Tetric Ceram®+Excite, and (8) Point 4®+OptiBond Solo Plus. At 14 days postoperatively, two independent operators, who did not take part in the clinical procedure, assessed postoperative teeth sensitivity using special questionnaires. Data were analyzed using non-parametric chi-square, Mann-Whitney and ANOVA tests. Results. Group 8 showed significantly higher score than the other groups. Less postoperative sensitivity was reported with two low-shrinkage composites (groups 2, 3, and 5) but with no significant difference. There was no statistical difference between groups 1, 2, 3, 4, 5, 6 and 7. Operator A had the highest postoperative sensitivity score compared to the other three. Conclusion. Conventional composite material Point 4® with its bonding agent caused significantly more postoperative sensitivity than low shrinkage composites combined with different adhesives. Operator skill influenced the incidence of postoperative sensitivity.Uvod. Posle postavljanja kompozitnih ispuna može da se javi postoperaciona osetljivost izazvana preparacionom traumom, sposobnošću adhezivnog sistema da hermetički zatvori dentinske kanaliće, deformacijom pod okluzalnim opterećenjem ili prodorom bakterijskih toksina. Cilj rada. Cilj istraživanja je bio da se ispita da li je osetljivost zuba manja kod kompozita s malom kontrakcijom u poređenju s konvencionalnim kompozitima i odgovarajućim adhezivnim sistemima, kao i uticaj veštine stomatologa na incidenciju postoperacione osetljivosti zuba. Metode rada. Na 960 premolara i molara stalne denticije s primarnim karijesom, pacijenata starosti od 21 godine do 40 godina, preparisani su kaviteti dubine 2-3 mm s rubovima u gleđi. Čitavu proceduru su obavila četiri specijalista stomatologije, od kojih su dva imala pet (A i B), a druga dva više od 20 godina kliničkog iskustva (C i D). Zubi su svrstani u osam grupa od po 120 uzoraka prema korišćenom kompozitnom i adhezivnom sistemu: 1) Els®+James-2; 2) Els®+James-2 (nova formula); 3) Els®+Excite; 4) InTenSe®+James-2; 5) InTenSe®+James-2 (nova formula); 6) InTenSe®+Excite; 7) Tetric Ceram®+Excite; i 8) Point 4®+OptiBond Solo Plus. Dve nedelje posle intervencije dva nezavisna stomatologa (koja nisu učestvovala u kliničkoj proceduri) ocenjivala su posebnim upitnicima postoperacionu osetljivost zuba. Podaci su analizirani neparametrijskim c2, Man-Vitnijevim (Mann-Whitney) i ANOVA testom. Rezultati. U osmoj grupi utvrđena je statistički značajno češća postoperaciona osetljivost nego u ostalim grupama zuba. Nije bilo statistički značajne razlike između grupa 1, 2, 3, 4, 5, 6 i 7. Kompoziti sa nižom polimerizacionom kontrakcijom izazvali su manju postoperacionu ostetljivost, ali bez statističke značajnosti razlika (grupe 2, 3 i 5). Kod stomatologa A javljala se statistički značajno češće postoperaciona osetljivost nego kod ostala tri. Zaključak. Tip kompozitnog materijala s odgovarajućim adhezivnim sistemom i spretnost stomatologa utiču na učestalost pojave osetljivosti zuba posle restauracija srednje dubokih kaviteta II klase

Identification of Agrobacterium vitis as a causal agent of grapevine crown gall in Serbia

In 2010, a serious outbreak of crown gall disease was observed on grapevines (Vitis vinifera L. cv. Cabernet Sauvignon) in several commercial vineyards located in the Vojvodina province, Serbia. Bacteria were isolated from the young tumor tissue on nonselective YMA medium and five representative strains were selected for further identification. Tumorigenic (Ti) plasmid was detected in all strains by PCR using primers designed to amplify the virC pathogenicity gene, producing a 414-bp PCR product. The strains were identified as Agrobacterium vitis using differential physiological and biochemical tests, and a multiplex PCR assay targeting 23S rRNA gene sequences. In the pathogenicity assay, all strains induced characteristic symptoms on inoculated tomato and grapevine plants. They were less virulent on tomato plants in comparison to the reference strains of A. tumefaciens and A. vitis. [Ministarstva nauke Republike Srbije, br. III46008: Development of integrated management of harmful organisms in plant production in order to overcome resistance and to improve food quality and safety

Morfološke odlike meziobukalnih kanala prvih maksilarnih molara

Introduction. The first maxillary molar is a tooth with three roots, and mesiobuccal one is with the most complex canal morphology. Factors influencing variations of its morphology are numerous, and may significantly complicate endodontic treatment. Objective. The objective was to investigate the number, configuration and curvature orientation of the mesiobuccal root canals in the maxillary first molars. Methods. The study was conducted on 200 mesiobuccal (MB) roots of extracted first molars in human subjects using radiography. In each canal Flexofile was introduced until reaching the apical foramen and the root was then radiographed in series from two projections. Number of root canals (MB1, MB2 and MB3), configuration according to Vertucci classification, and the orientation of the curvature were established. Relevant statistical parameters and the significance of differences were computed (p lt 0.05). Results. Of total 200 mesiobuccal roots 86.5% were with two, 9% with three, and 4.5% with a single canal. Most frequent configurations were type IV (36%) and II (34.5%). From the clinical projection all MB1 canals were oriented distally, from the proximal 78% palatally and 22% buccally. The orientation of all MB2 canals was distal from the clinical projection, from the proximal projection 76% were oriented palatally, and 24% buccally. The MB3 canal was always oriented distally from the clinical projection, and buccally from the proximal aspect. Conclusion. The mesiobuccal roots of the first maxillary molars showed multiple canals in 96%, with dominant Vertucci type II and IV of configuration. All canals were curved.Uvod. Prvi maksilarni molar je zub koji najčešće ima tri korena, a meziobukalni je s najsloženijom kanalnom morfologijom. Faktora koji utiču na varijabilnost njegove morfologije ima mnogo i značajno otežavaju endodontsko lečenje ovih zuba. Cilj rada. Cilj rada je bio da se na ekstrahovanim prvim maksilarnim molarima ispitaju broj, konfiguracija i smer povijenosti meziobukalnih kanala. Metode rada. Istraživanja su urađena na 200 meziobukalnih (MB) korenova ekstrahovanih humanih prvih maksilarnih molara metodom radiografisanja. U svaki pojedinačni kanal postavljen je instrument tipa Flexofile do pojave na anatomskom otvoru i zatim radiografisan serijom snimaka iz dve projekcije. Zabeleženi su broj kanala (MB1, MB2 i MB3), konfiguracija prema Vertučijevoj (Vertucci) klasifikaciji i smer povijenosti. Utvrđeni su relevantni statistički parametri i razlike na nivou značajnosti p lt 0,05. Rezultati. Od ukupno 200 MB korenova, sa dva kanala bilo je njih 86,5% , sa tri 9%, a s jednim kanalom 4,5%. Najčešći tipovi kanalne konfiguracije bili su IV (36%) i II (34,5%). Smer povijenosti svih MB1 kanala iz kliničke projekcije bio je distalan, a iz aproksimalne 78% palatinalan i 22% bukalan. Svi MB2 kanali iz kliničke projekcije bili su distalno povijeni, a iz aproksimalne 76% palatinalno i 24% bukalno. MB3 kanal je bio povijen uvek distalno u kliničkoj, a najčešće bukalno u aproksimalnoj projekciji snimanja. Zaključak. Meziobukalni korenovi prvih maksilarnih molara su u 96% slučajeva imali višestruki broj kanala i konfiguracijski su pripadali tipu IV i II Vertučijeve klasifikacije. Svi kanali su bili povijeni

Diferencijacija Pseudomonas syringae patogenih varijeteta poreklom iz koštičavih voćaka

Due to an overlapping host range, similar symptomatology and many common characteristics, Pseudomonas syringae pathovars originating from stone fruits can easily be misidentified. In order to select tests for rapid and efficient differentiation of P. s. pvs. syringae, morsprunorum and persicae, we studied the suitability and differentiating potential of some standard bacteriological and molecular methods. Differentiation of the strains was performed using LOPAT, GATTa and ice nucleation tests, nutrient sucrose broth growth and utilization of various carbon sources. PCR method enabled the detection of toxin-producing genes: syrB and syrD in P. s. pv. syringae, and cfl gene in P. s. pv. morsprunorum race 1. Syringomycin production by pv. syringae was confirmed in bioassay using Geotrichum candidum, Saccharomyces cerevisiae and Rhodotorula pilimanae as indicator organisms. Pathogenicity test on lemon and immature nectarine fruits, as well as on string bean pods, showed different intensity of reaction of the inoculated material which could separate pv. syringae from the other two pathovars. PCR-based repetitive sequences, Rep-PCR with REP, ERIC and BOX primers revealed different genetic profiles within P. syringae pathovars.Patogeni varijeteti Pseudomonas syringae poreklom sa koštičavih voćaka poseduju brojne zajedničke karakteristike u pogledu kruga domaćina, simptomatologije i biohemijskofizioloških osobina, što otežava njihovu identifikaciju. U cilju odabira testova pogodnih za brzu i pouzdanu identifikaciju P. s. pv. syringae, morsprunorum i persicae, primenjeni su standardni bakteriološki i molekularni testovi. Diferencijacija sojeva izvršena je LOPAT i GATTa testovima, posmatranjem razvoja u hranljivom rastvoru sa saharozom, sposobnošću sojeva da formiraju čestice leda, kao i mogućnošću korišćenja različitih ugljenikovih jedinjenja. PCR metod korišćen je u detekciji gena odgovornih za proizvodnju toksina siringomicina kod soja P. s. pv. syringae (syrB i syrD geni) i koronatina kod soja P. s. pv. morsprunorum rase 1 (cfl gen). Proizvodnja siringomicina potvrđena je i biotestom, korišćenjem gljiva Geotrichum candidum, Saccharomyces cerevisiae i Rhodotorula pilimanae kao indikatora. Proverom patogenosti sojeva na plodovima limuna, nesazrelim plodovima nektarine i mahunama boranije, došlo je do ispoljavanja simptoma različitog intenziteta, na osnovu kojih se može izdvojiti pv. syringae od ostala dva patovara. Primenom Rep-PCR metode, uz korišćenje REP, ERIC i BOX prajmera, ustanovljene su razlike u genetskim profilima proučavanih P. syringae patogenih varijeteta

Oblikovanje krstaste osovine sa aspekta nosivosti

To ensure the quality of mechanical parts it is necessary to fulfill the basic constructional requirements that are related to the form, function, material and manufacturing procedure. Form of mechanical parts is the result of adjusting all of those requirements, and the task of constructor is the development of forms with the aim of finding the best solution. This paper describes the procedure to determine the effect of geometry changes to stress level in cross shaft Cardan joint. The task of the Cardan joint is mechanical transmission of power and motion between shafts that are changing the position of axis in the process of exploitation and are placed by a certain angle. Cross shaft is one of the most important parts of the Cardan joint. In most cases the size and lifetime depend on the Cardan joint from the cross shaft. The critical stress at the cross shaft was calculated by analytic method and tested by numerical simulation. It is shown how small changes in geometry of cross shaft can lead to a significant reduction in critical stress. By the means of iterative correction of form and repetition of the numerical calculation of stress, favorable ration between the geometry of cross shaft and extreme values of stress has been obtained

Specificity and sensitivity of three pcr-based methods for detection of erwinia amylovora in pure culture and plant material

Three PCR methods, referred in this study as,conventional" "nested" and,chromosomal" PCR and suggested for routine detection of Erwinia amylovora in pure culture and plant material, were evaluated according to their specificity and sensitivity. Specificity of PCR methods was analyzed by using 42 strains of E. amylovora, originating from different locations and plant species, with diverse PFGE profiles, representing distant populations of the pathogen. Sensitivity of PCR protocols in pure culture was studied by using nine different concentrations of E. amylovora in sterile ultrapure water as a template in PCR reactions. In order to study inhibitory effect of plant DNA and other inhibitors on sensitivity of the three PCR methods bacterial dilutions were mixed with plant macerate of pear, apple and quince prior to the PCR reaction. In specificity assays, tested PCR protocols were able to detect all E. amylovora strains regardless of the host of the strain, its origin or PFGE group, indicating primer specificity. On the other hand, sensitivity among tested methods varied, depending on bacterial concentration and selected plant material used in the PCR. When working with pure cultures nested PCR showed the greatest sensitivity by detecting 1.9 bacterial cells per PCR reaction, followed by detection limit of 9.5 cells per PCR reaction with conventional PCR and 1.9.105 cells/PCR reaction with chromosomal PCR. In spiked samples plant inhibitors either did not affect or they decreased the sensitivity of the PCR reaction, depending on the protocol and/or type of plant macerate. In our experiments, inhibitors from pear and quince macerates did not affect sensitivity of nested PCR, while apple macerate reduced its sensitivity by a factor of 10. Conventional PCR protocol was able to detect 95 cells/PCR reaction in pear and apple macerate, but only 9.5.103 cells/PCR in quince macerate. Greatest decrease in sensitivity of the PCR method was observed in spiked samples with chromosomal PCR since bacterial DNA was not detected in each of the spiked samples. Our research shows that all three PCR protocols are specific for detection of E. amylovora, but nested PCR proved to be most sensitive when working with pure cultures and plant material

Analiza masnih kiselina sojeva Erwinia amylovora iz Srbije i Crne Gore

Automated method of fatty acid analysis was used to identify and study heterogeneity of 41 Erwinia amylovora strains, originating from 8 plant species grown in 13 locations in Serbia and one in Montenegro. All strains contained 14:0 3OH fatty acid, characteristic for the 'amylovora' group. According to fatty acid composition 39 strains were identified as E. amylovora as the first choice from the database. Due to their specific fatty acid composition, two strains were identified as E. amylovora, but as a second choice. Fatty acid analysis also showed that E. amylovora population from Serbia could be differentiated in three groups, designated in this study as α, β and γ. All strains originating from central or south Serbia, as well as four strains from north Serbia clustered into group α. Group β and γ contained only strains isolated in northern Serbia (Vojvodina). The results show that E. amylovora population in this area is heterogeneous and indicate pathogen introduction from different directions. Fatty acid analysis enabled identification at species level, as well as new insights of heterogeneity of E. amylovora population.Automatizovana metoda analize masnih kiselina primenjena je za identifikaciju i proučavanje heterogenosti Erwinia amylovora. Kao materijal za analizu prikupljen je 41 soj E. amylovora izolovan iz 8 različitih vrsta domaćina gajenih u 13 lokaliteta u Srbiji i jednom lokalitetu u Crnoj Gori. Rezultati ukazuju da svi proučavani sojevi poseduju 14:0 3OH masnu kiselinu, koja je karakteristična za 'amylovora' grupu. Na osnovu sastava masnih kiselina 39 sojeva je identifikovano kao E. amylovora, kao prvi izbor iz baze podataka. Dva soja su identifikovana kao E. amylovora, ali tek kao drugi izbor iz baze podataka, što je najverovatnije posledica specifičnosti u sastavu njihovih masnih kiselina. Rezultati analize masnih kiselina takođe pokazuju da populacija E. amylovora poreklom iz Srbije nije homogena i da među sojevima postoje tri grupe ili profila, koji su u ovom radu obeleženi sa α, β i γ. Svi sojevi koji su izolovani na prostoru centralne ili južne Srbije pripadaju grupi α, kao i četiri soja izolovana na području Vojvodine. Grupama β i γ pripadaju samo sojevi izolovani na području Vojvodine. Dobijeni rezultati predstavljaju dokaz heterogenosti populacije E. amylovora na ovim prostorima i ukazuju na mogućnost prodora patogena u naše područje iz različitih pravaca. Analiza masnih kiselina omogućila je ne samo identifikaciju do nivoa vrste, već i nova saznanja o heterogenosti populacije E. amylovora na ovim prostorima

Endodontsko lečenje zuba s različitim oblicima krivina korenskih kanala - dva prikaza iz prakse

Endodontic treatment of the teeth with severe root canal curvatures has become one of the greatest problems in clinical practice. Recently, new instruments and techniques have been introduced in the endodontic procedure. The aim of this study was, on the basis of clinical practice, to show the possibilities of the endodontic treatment in the teeth with severely curved root canals, after dependable decision about endodontic instruments and techniques. This article presents a complete endodontic procedure in two teeth with different curvature shape of the root canal in patients that were treated at the Department of Restorative Dentistry and Endodontics, School of Dentistry, Belgrade. Coronal to apical 'crown down' technique was used for the root canal preparation with hand NiTi ProTaper instruments with progressive multicone design. The main reasons for choosing manual technique were complexity, shape of presented curvatures and better tactile sensation control of canal instruments in order to avoid possible mistakes and complications. Clinical X-rays of the teeth with permanent obturation clearly showed that extremes of the root canal morphology could be successfully solved by the right choice of all factors during endodontic procedure.Endodontsko lečenje zuba s jako zakrivljenim korenovima je značajan problem u praksi. Primena novih instrumenata i tehnika u lečenju ovakvih zuba poslednjih godina je postala sve izvesnija.Cilj ovog rada je bio da se na primerima iz kliničke prakse ukaže na mogućnost endodontskog lečenjazuba s veoma izraženim krivinama kanala korena nakon pravilnog izbora endodontskih instrumenata, odnosno tehnike instrumentacije. U ovom radu je prikazan celokupni endodontski postupak lečenja dva zuba pacijenata Klinike za bolesti zuba Stomatološkog fakulteta u Beogradu sa različitim oblicima krivine centralnog korenskog kanala. Prime-njena je krunično-apeksna 'crown-down' tehnika preparacije uz korišćenje ručnih nikl-titanijumskih instrumenata tipa ProTaper s progresivnom multikoničnošću. Osnovni razlozi za odabir ručne tehnike preparacije bili su složenost morfologije, oblik prikazanih krivina i bolja taktilno-senzorna kontrola kanalnih instrumenata; cilj je bio da se izbegnu moguće greške i komplikacije. Prikazani radiografski snimci zuba sa jasno opturiranim kanalnim sistemom pokazuju da su i ekstremi morfološkog izgleda kanala rešivi pravilnim odabirom svih činilaca endodontske procedure.