Naslov Pojavnost dentinskih mikrofraktura kod različitih tehnika instrumentacije korijenskih kanala Naslov (engleski) Incidence of dental microfractures as a result of using different tehniques of root canal instrumentation Autor Tomislav Katanec310744676 Mentor Silvana Jukić Krmek (mentor)Mentor Lumnije Kqiku Biblekaj (komentor)305695244 Član povjerenstva Nada Galić (predsjednik povjerenstva)Član povjerenstva Goranka Prpić-Mehičić (član povjerenstva)Član povjerenstva Mato Sušić (član povjerenstva)Član povjerenstva Mirza Žižak (član povjerenstva)Član povjerenstva Zoran Karlović (član povjerenstva)Ustanova koja je dodijelila Sveučilište u Zagrebu Datum i država obrane 2020-06-30, Hrvatska Znanstveno / umjetničko BIOMEDICINA I ZDRAVSTVO Univerzalna decimalna klasifikacijaUDC ) 616.31 - Stomatologija Sažetak Mikrofrakture korijenskog dentina koje mogu dovesti do vertikalne frakture korijena, nastale kao posljedica kemomehaničke obrade korijenskih kanala, često se povezuju s različitim postupcima tijekom endodontskoga liječenja. Prednost mikro CT metode u odnosu na sekcijske metode je njena neinvazivnost i mogućnost usporedbe uzorka prije i nakon eksperimenta. Svrha ovog rada je bila procijeniti utjecaj obrade korijenskih kanala instrumentima nove generacije, Self Adjusting File, Reciproc Blue i ProTaper Next s tri različite vrste pokreta u korijenskom kanalu na pojavnost mikrofraktura pomoću mikro CT-a i otpornost tako obrađenih korijenova na djelovanje pritisnih sila. U istraživanju je korišteno 57 gornjih premolara s dva korijenska kanala ekstrahirana zbog ortodontskih razloga od pacijenata u dobi od 16 do 20 godina. Uzorci su dekororirani i uronjeni u akrilatne blokove, a parodontni ligament je imitiran polisiksanskim materijalom za otiske. Zubi su skenirani pri strukturnoj rezoluciji od 20,2 μm industrijskim mikro CT-om (Nikon XT H 225, Tring, UK) i randomizirano su podijeljeni u tri grupe koje su obrađene trima sustavima instrumentacije kanala: Self Adjusting File (vibracijske kretnje), Reciproc Blue (recipročne kretnje) i ProTaper Next (rotacijske kretnje). Kanali su obrađeni prema uputama proizvođača uz predpripremu „glide path“ instrumentima. Tijekom instrumentacije kanali su irigirani 12 ml 2,5% NaOCl i 4 ml 17% EDTA, svaki. Uzorci su ponovo skenirani pod istim uvjetima i 24 sata nakon njihovog sušenja. Za analizu pojavnosti mikrofraktura u stijenkama dentina korišten je program Volume Graphics VGStudio Max 3. Poslije toga uzorci su prerezani na tri dijela i podvrgnuti ispitivanju otpornosti na pritisnu silu univerzalnom kidalicom. Ni jedan dentinski defekt nije pronađen prije i nakon obrade kanala, kao ni nakon 24 sata sušenja na suhom zraku. Rezultati testiranja otpornosti na lom nisu pokazali statistički značajnu razliku između skupina. Pod uvjetima ovog istraživanja može se zaključiti da obrada kanala mladih pretkutnjaka vibracijskim Self Adjusting File, recipročnim Reciproc Blue i rotacijskim ProTaper Next instrumentima ne dovodi do pojave mikrofraktura u stijenci korijenskih kanala, a korijeni instrumentirani ovim tehnikama ne pokazuju statistički značajne razlike u otpornosti na lom djelovanjem pritisne sile.
Sažetak (engleski) Introduction: Controversies about effects of the forces formed during root canal treatment on dentinal microcracks formation still exist due to different results reported. The issue of methodology, sample selection and storage of the specimens still require further analysis, particularly because new instruments are constantly being developed. The aim of the study was to explore microcrack formation after root canal preparation with Self-adjusting File (SAF), Reciproc Blue (RB), and ProTaper Next (PTN) instruments on young premolars by means of micro computed tomography.
Methods: Fifty-seven premolars, two-rooted with one canal (Vertucci type I) or single-rooted teeth of Vertucci type II had been used for the study All the teeth were visually inspected under the stereomicroscope with magnification of 12 x to exclude those with open apices, those that were root fractured during the extractions and pre-existing dentinal defects. The
specimens were decoronated using a diamond disc to standardize the working length about 12 mm. The periodontal ligament was simulated by a thin layer of polysiloxane impression material on the root surface and the samples were embedded in blocks made of acrylic resin. Specimens were scanned at geometrical magnification of 6.3, which yielded a structural resolution of 20.2 μm. All teeth were scanned at X-ray energy of 110 kV and X-ray tube current of 140 μA with a 0.1 mm Cu filter, using 1440 projections at an exposure time of 333 ms. Beam hardening was reduced using a Hanning filter. Noise was reduced using a median filter, and surface detection was performed using an adaptive search algorithm (Volume Graphics VGStudio Max 3). Samples were randomly assigned into three groups of 19 teeth each according the instrumentation technique: Self-Adjusting File (SAF), Reciproc Blue (RB), and ProTaper Next (PTN) For the SAF group (vibration kinematics), the glide path was created using the Pre-SAF set of instruments (ReDent Nova). An RDT3 handpiece was used for canal preparation with SAF instrument 1.5 mm in diameter at frequency of 5000 vibrations per minute and amplitude of 0.4 mm for a total of four minutes. The canals were simultaneously irrigated with 2.5% NaOCl at a flow rate of 4 ml/min for three minutes and one minute with 4 ml of 17% ethylenediaminetetraacetic acid (EDTA) by use of a syringe and needle. In the RB group (reciprocation kinemamatics), glide path was created with R-Pilot (WDV, Munich, Germany)
followed with Reciproc Blue until the working length was reached The glide path in the PTN group (full rotary kinematics) was created with Proglider (Dentsplay Maillefer) ProTaper Next X1 and subsequently ProTaper Next X2 were each used
in a brushing motion at a speed of 300 rpm with torque set to 4 Ncm to progress apically until reaching the working length. During instrumentation in RB and PTN group, each canal was irrigated with 12 ml of 2.5% NaOCl, and final irrigation was performed with 4 ml of 17% EDTA to match the irrigation protocol used in SAF grous. After the root canal preparation, post-operative scans were performed in the same specimen positions and with the same micro-CT parameters as the first scan.
In order to check the influence of the moisture on visibility of microcracks, specimens were kept in dry conditions for 24 hours and then scanned for the third time. Two calibrated, blinded examiners evaluated the cross-sectional images using the imageprocessing software Volume Graphics VGStudio Max 3. The roots were divided into cervical, middle, and apical parts. Radiolucent lines present in the micro-CT sections would be categorized as microcracks. If the microcracks had been observed on post-operative scans, the corresponding pre-operative scan would have been analyzed to exclude pre-existing defects. Ten specimens of each group were cut in horizontal slices and tested on fracture resistance in a universal testing machine AGS-X, Shimadzu (Japan) at speed 0,5 mm/min.
Results: No dentinal defect was found in any evaluated specimen, neither in pre- and nor postoperative scans in wet and dry condition. PTN group showed the lowest value for fracture resistance (419,15 N) compering to RB (485,57 N) and (473,12 N). The differences were not statistically significant (p=0.151).
Conclusion: Under the circumstances of this study instruments with three different kinematics (SAF, Reciproc Blue and Protaper Next) do not cause dentinal microcracks in young premolar teeth and does not cause differences in resistance to load to fracture.
Ključne riječi
dentinske mikrofrakture
mikro CT
rotacijski endodontski instrumenti
recipročni endodontski instrumenti
samoprilagođavajući instrument
tlačna čvrstoća
Ključne riječi (engleski)
dentinal microcracks
micro-computed CT
rotary endodontic instruments
reciprocating endodontic instruments
Self Adjusting File
Jezik hrvatski URN:NBN urn:nbn:hr:127:749292 Datum promocije 2020 Studijski program Naziv: Dentalna medicina Vrsta resursa Tekst Opseg 123 str. Način izrade datoteke Izvorno digitalna Prava pristupa Otvoreni pristup Uvjeti korištenja Datum i vrijeme pohrane 2020-11-25 13:44:24
