3683 research outputs found
Sort by
Influence of Dental Impression Materials on Metal Artifact in Cone Beam Computed Tomography Examination
No full textAbstract: Aim: To estimate the effect of different dental impression materials on cone beam computed tomography (CBCT) metal artifact at different resolutions and fields of view (FOVs).
Material and Methods: A model of the mandible with restored human teeth was created. Six dental materials were molded as teeth overlays to uniform thickness: A-Silicones (Elite HD+, and Vonflex S Putty), Alginate (Tropicalgin), Pink wax (MBwax1), C-Silicon (Zetaplus) and Zinc-oxide (COE-PAK). The model alone (control) and with teeth covered by each of the materials, was scanned using CBCT Unite KAVO dent at two different fields: 5x5 (FOV S) and 6x8cm (FOV M), and three different resolutions: low (0.28-S; 0.32-M), standard (0.20-S; 0.30-M), and high (0.125-S; 0.20-M). Two experienced radiologists analyzed a single representative view of each dataset in Image J: quantitatively- by histogram analysis within the selected regions of interest (ROI), and qualitatively (using a five-point Likert scale). The data were analyzed using standard one-way analysis of variance (ANOVA). Inter-rater reliability was examined.
Results: Intraclass Correlation Coefficient for all measurements was between 0.806- 0.996. At low resolution level and FOV S, Zetaplus and Vonflex S Putty showed significantly lower variance and range in grayscale values compared to the control, as well as a higher quality score. With higher resolution levels, image quality improved, but showing no significant differences between the control and tested materials.
Conclusion: Covering teeth with dental materials such as Vonflex S Putty and Zetaplus, can reduce the image noise in small field of view and at low resolution level.Dostupno na: [https://www.mybir.org.uk/l/s/poster-details?recordId=a3xQC000000WI6RYAW&language=en_GB
CT analysis of masseter muscle composition in age-related sarcopenia: preliminary results
No full textBackground
CT-assessed masseter muscle (MM) cross-sectional area and thickness have been recently
highlighted as independent predictors of age-related sarcopenia. This study aimed to investigate
MM composition in aging adults and its relationship with sarcopenia.
Methods
Twenty adults who were referred to the CT examination of the head and neck were selected.
Selection criteria were the absence of malignant disease, neurodegenerative and muscle
disease, and developmental facial anomalies. Age, gender, body height (BH), body weight (BW),
and the number of missing teeth (NMT) were recorded. Patients were divided into a sarcopenia
group (5 male and 5 female; mean age 69.3 ± 11.1) and a control group (5 male and 5 female;
mean age 53.2 ± 7.16) based on the CT-assessed skeletal muscle index (SMI). A referent non-
contrast CT image of MM at the level of the mandibular foramen was used to assess muscle
composition bilaterally. Mean MM density (in Housfield units, HU), percentage of low-density
muscle (LDM, pixel density between 0 and 30 HU), and the ratio between LDM and normal-
density muscle (NDM, pixel density between 30-100) were measured. Statistical analyses were
performed in SPSS.
Results
The sarcopenia group had significantly lower mean MM density (48.9±6.8 vs. 69.2±9.2;
p<0.001), higher LDM percent (20.6±7.7 vs. 4.6±4.2; p<0.001), and higher LDM/NDM ratio
(0.3±0.1 vs. 0.1±0.1; p=0.001) in comparison to the control group. Mean MM density showed a
significant negative correlation with age and NMT. LDM and LDM/NDM correlated significantly
with age and NMT. Only LDM/NDM correlated significantly with SMI.
Conclusion
Aging and tooth loss significantly impair the MM composition, while the impact of sarcopenia
needs to be assessed in a larger sample.Poster Number: C-2641
Uticaj dizajna flapa za hiruršku ekstrakciju donjeg impaktiranog umnjaka na postoperativni tok - diplomski rad
No full textOsim adekvatnog pristupa, dizajn flapa tokom hirurškog vađenja impaktiranih
donjih umnjaka može biti od značaja i za redukciju postoperativnih
komplikacija. Cilj rada je poređenje i praćenje postoperativnog toka, nakon
hirurške ekstrakcije impaktiranih donjih umnjaka, između pacijenata kod kojih
je urađen envelop režanj i pacijenata kod kojih je urađen trougaoni režanj.
Istraživanjem je obuhvaćeno ukupno 20 pacijenata podeljenih u dve grupe –
envelop i standardni trougaoni režanj (n=10). Za svakog pacijenta je zabeležena
starosna dob, indikacija za vađenje zuba, klasifikacija umnjaka koji se vadi (Pell
Gregory i Winter), kao i da li je izvađen njegov antagonista. U toku hirurške
ekstrakcije praćena je dužina trajanja intervencije, da li je došlo do separacije
krunice i korena i da li je rana primarno ušivena. U četiri vremena
(preoperativno, prvi, treći i sedmi postoperativni dan) su praćeni bol
(vizuelno-analogna skala), otok, stepen otvaranja usta, parodontalni status
drugog molara, broj uzetih analgetika i pojava komplikacija (dehiscencija,
krvarenje, infekcija, alveolitis, parestezija). Subjektivne promene pacijenta su
procenjene pomoću upitnika o socijalnoj izolaciji, ishrani, govoru, spavanju i
izgledu.
U postoperativnom periodu od sedam dana, oba ispitivana dizajna flapa,
envelop i trougaoni, su praćena sličnim postoperativnim
komplikacijama i kvalitetom života
Dijagnostika oboljenja pljuvačnih žlezda - diplomski rad
No full textPljuvačne žlezde imaju važnu ulogu u varenju, govoru i održavanju oralnog
zdravlja, a njihova oboljenja, iako ređa, značajno utiču na kvalitet života pacijenata.
Zbog sličnosti u kliničkim slikama, dijagnostika ovih oboljenja zasniva se na
detaljnoj anamnezi, kliničkom pregledu i savremenim metodama vizualizacije, poput
RTG-a, UZ-a, CT-a i MRI-a, dok sijalografija i scintigrafija imaju specifičnu primenu
u određenim stanjima. Biopsija, posebno labijalna, ključna je u potvrđivanju
autoimunih bolesti.
Kombinacija kliničkog, radiološkog i histološkog pristupa omogućava
pravovremeno postavljanje dijagnoze, adekvatan izbor terapije i poboljšanje ishoda
lečenja
Uticaj rasporeda preostalih zuba na stabilnost parcijalne skeletirane proteze – uporedna analiza različitih modela - diplomski rad
No full textTema ovog diplomskog rada je „Uticaj rasporeda preostalih zuba na stabilnost
parcijalne skeletirane proteze – uporedna analiza različitih modela“. Cilj rada je bio
da se istraži kako raspored preostalih zuba utiče na izbor konstrukcije, biomehaničku
stabilnost i funkcionalnost parcijalne proteze, uz primenu Kennedy klasifikacije i
podklasa. U radu su analizirani osnovni principi parcijalnih skeletiranih proteza,
uključujući oslonac, retenciju i stabilizaciju, kao i delovi proteze: velika i mala
spojnica, nasloni, kukice i baza proteze. Posebna pažnja posvećena je okluziji kod
krezubih pacijenata, njenim promenama nakon gubitka zuba i njenoj ulozi u
stabilnosti proteze. Takođe, obrađena je uloga rasporeda preostalih zuba u planiranju
oslonaca i retencijskih elemenata, sa osvrtom na različite Kennedy klase i podklase.
Analiza pokazuje da simetrično raspoređeni preostali zubi i pravilno projektovani
nasloni, kukice i vodeće ravni značajno povećavaju stabilnost proteze, dok
asimetričan raspored i slobodna sedla zahtevaju precizno planiranje biomehanike
kako bi se sprečila rotacija i preopterećenje zuba nosača. Zaključeno je da raspored
preostalih zuba i izbor konstrukcije imaju direktan uticaj na funkcionalnost i
dugotrajnost parcijalne skeletirane proteze, te da svaki slučaj krezubosti zahteva
individualni plan terapije, uzimajući u obzir Kennedy klasu, podklasu i stanje
alveolarnog grebena, kako bi se postigla optimalna stabilnost, okluzija i komfor
pacijenta
Application of SEM analysis in the evaluation of surface characteristics of contemporary prosthetic materials after professional hygiene procedures
No full textScanning electron microscopy (SEM) offers a high-resolution method for detecting microstructural surface
changes in dental materials caused by routine professional hygiene procedures. This in vitro study utilized
SEM to investigate the effects of ultrasonic scaling and professional brushing on the surface microtopography
of zirconia restorations, fabricated by CAD/CAM milling or veneered with ceramic. Specimens (n = 36;
4 × 4 × 2 mm) were obtained from 3Y-TZP-LA zirconia blocks and divided into four groups based on surface
finish (polished or glazed) and fabrication method. Each subgroup was subjected to either ultrasonic scaling
or brushing with an abrasive polishing paste for 1 minute, repeated in 10 cycles to simulate the effects of five
years of clinical maintenance SEM imaging at 150×magnification (Model JSM-6390, JEOL, Japan) was
performed before and after treatment to evaluate micromorphological changes. SEM allowed precise
identification of surface defects, including microcracks, abrasive wear and glaze degradation. The most
significant changes were observed in glazed samples exposed to ultrasonic scaling, with surface alterations
measured at 88.31 μm for veneered zirconia and 45.38 μm for CAD/CAM-milled zirconia.The results
demonstrate that standard professional hygiene procedures can significantly affect the surface integrity of
glazed zirconia restorations. SEM analysis proved to be an essential diagnostic tool for early detection of
clinically relevant surface damage, offering insights into material behavior and supporting the development of
tailored maintenance protocols.Dostupno na: [http://cnntechno.com/docs/9_CNN_book_of_abstracts_fin.pdf
The impact of dental impression materials on metal artifacts in cone beam computed tomography examination
No full textAbstract
Objectives
To estimate the impact of different dental impression materials on cone beam computed tomography (CBCT) metal artifacts at different resolutions and fields of view (FOVs).
Methods
A mandible model with restored human teeth was created. Six dental materials were molded as teeth overlays with uniform thickness: A-silicones (Elite HD + , and Vonflex S Putty), Alginate (Tropicalgin), Pink wax (MBwax1), C-Silicon (Zetaplus) and Zinc-oxide (COE-PAK). The model alone (control) and with teeth covered with each material was scanned using CBCT Unite KAVO dent at two different FOVs—5 × 5 (S) and 6 × 8 cm (M), and three different resolutions: low (0.28-S; 0.32-M), standard (0.20-S; 0.30-M), and high (0.125-S; 0.20-M). Two experienced radiologists analyzed a single representative view of each dataset in ImageJ quantitatively—by conducting a histogram analysis within the selected regions of interest (ROI) and qualitatively (using a five-point Likert scale). The data were analyzed using standard one-way analysis of variance (ANOVA). Inter-rater reliability was examined.
Results
The intraclass correlation coefficient for all quantitative measurements was between 0.806 and 0.996. Within FOV S, Vonflex S Putty showed significantly lower variance and range in grayscale values compared to the control at all resolution levels, while Zetaplus followed the same trend only at low resolution. As for FOV M, none of the tested materials significantly differed from the control in both variance and range. The qualitative analysis showed no significant differences when using overlays in comparison with uncovered teeth.
Conclusions
Although without significant improvements in the image quality, covering teeth with dental materials quantitatively reduced artifacts
Karcinomi usana i hirurške metode rekonstrukcije - diplomski rad
No full textKarcinomi su maligni tumori epitelnog porekla i mogu nastati samo iz epitelnih struktura. U ovom slučaju to su koža, sluzokoža i male pljuvačne žlezde. Karcinomi usana predstavljaju jednu od najčešćih malignih bolesti regije glave i vrata. Najčešća lokalizacija ovih karcinoma jeste donja usna (89%), pri čemu je planocelularni karcinom najčešći histološki tip. U 95% slučajeva se javlja kod muškaraca, dok se kod žena javlja u svega 5%. Glavni faktori rizika uključuju hroničnu izloženost UV zračenju, pušenje i alkohol. Zbog svoje lokalizacije, karcinomi usana se relativno rano otkrivaju, što omogućava povoljniju prognozu u poređenju sa drugim malignitetima u ovoj regiji.
Za dijagnozu karcinoma neophodno je uzeti detaljnu anamnezu, obaviti adekvatan klinički pregled i primeniti odgovarajuća dopunska dijagnostička sredstva. U cilju postavljanja definitivne dijagnoze radi se odgovarajuća biopsija. Nejasne lezije sluzokože usne duplje koje ne zarastaju za 10 do 14 dana, moraju se smatrati sumnjivim na malignitet sve dok se histopatološkim pregledom isečka tkiva uzetog biopsijom sa sumnjivog mesta ne dokaže suprotno.
Klinički, karcinomi vermiliona usne imaju karakterističan egzofitičan izgled nalik na karfiol, može biti ulcerisan ili može imati endofitični nodularni izgled.
Najbolji terapijski rezultat postiže se hirurškom terapijom koja podrazumeva eksciziju tumora do u zdravo tkivo. Primena lokalnih, regionalnih i slobodnih režnjeva omogućava očuvanje funkcije i estetike usana. Najčešće korišćene metode su Abbe Estlander, Karapandžić i Webster režnjevi, koji obezbeđuju zadovoljavajuće funkcionalne i estetske ishode
Minimalno invazivni pristup u fiksnoj stomatološkoj protetici: adhezivni mostovi - diplomski rad
No full textMinimalno invazivni pristup u fiksnoj stomatološkoj protetici predstavlja prioritet za
očuvanje zdrave zubne supstance. Ovaj rad analizira adhezivne mostove, sa posebnom
pažnjom usmerenom ka Maryland mostovima, kao predstavniku minimalno invazivnog
pristupa. Pored toga prikazane su ključne karakteristike materijala koji se koriste poput
keramike i vlaknima ojačanih kompozitnih materijala. U radu su detaljno analizirane
indikacije i kontraindikacije, prednosti i mane ovih tehnika. Rad naglašava značajan
doprinos adhezivnih mostova minimalno invazivnoj stomatologiji, omogućavajući
pacijentima zadovoljavajuću funkciju i estetiku
Bolesti temporomandibularnog zgloba - diplomski rad
No full textOboljenja temporomandibularnog zgloba obuhvataju različit spektar promena: u unutrašnjosti samog zgloba, zapaljenja vezivnog tkiva, funkcionalne smetnje, poremećaji na kondilu itd. Manifestuju se simptomima od kojih su neki: ograničeni pokreti, krepitacije, malokluzije i bol koji može da zahvati mišiće lica, vrat i glavu. U dijagnostičke svrhe služimo se inspekcijom (tražimo asimetrije u izgledu, crvenilo, postojanje devijacije i defleksije...), palpacijom zglobnih jama, i koristimo se snimanjem (magnetna rezonanca, skener, ultrazvuk) i histološkim ispitivanjima, ako je potrebno. Terapijske procedure daju prednost konzervativnim metodama (analgetici, mišićni relaksansi, lokalni anestetici, kortikosteroidi) i fizioterapiji (mirovanje, obloge, vežbe pokretljivosti i masaže), a kod težih slučajeva obuhvataju i hirurško lečenje