Search

Uvod: Zahvaljujući svakodnevnom razvoju tehnologije, konvencionalni način otiskivanja sve češće biva zamenjen digitalnim. Postupa 3d digitalizacije se zasniva na prikupljanju podataka u vidu koordinata-tačaka, koje se potom prevode u digitalnu formu. U upotrebi su brojni skeneri različitih proizvođača čije se mogućnosti neprestano unapređuju. Cilj rada: Cilj istraživanja je bio da se uporedi tačnost različitih intraoralnih skenera “Virtuo Vivo” i “3 Shape TRIOS 3” . Materijal i metod: U donjoj vilici zbrušeni su: očnjak, drugi premolar i drugi molar sa desne strane. Standardnom perforiranom kašikom uzet je otisak donje krezube vilice adicionim silikonom, nakon čega je izliven model od supertvrdog gipsa. Posle vezivanja gipsa, model je skeniran po 10 puta “Virtuo Vivo”i“3 Shape TRIOS 3” interolarnim skenerima. Dobijeni digitalni modeli sačuvani su u STL formatu. U programu GOM Inspect digitalni zapisi različitih skenera su preklopljeni. Svaki digitalni zapis jednog skenera upoređen je sa svih 10 zapisa drugog skenera. Za svaki par je dobijena vrednost odstupanja izražena u milimetrima. Za digitalni master model uzet je par koji je pokazao najmanju vrednost odstupanja. Svaki digitalni zapis oba skenera preklopljen je sa master modelom. Dobijeni podaci su analizirani SPSS-u. Rezultati: Srednja vrednost odstupanja digitalnih zapisa “3 Shape TRIOS 3” skenera je 0,03 plus minus 0,02, a “Virtuo Vivo”0,09 plus minus 0,04. Zaključak: Oba skenera imaju preciznost prihvatljivu za svakodnevnu kliničku primenu. Veću tačnost pokazao je “3 Shape TRIOS 3”.

Keramičke fasete su tanke ljuspe koje su trajno adhezivno cementirane za zubne strukture i izrađuju se u cilju korekcije nepravilnosti postojećih zuba. Indikuju se kada je prisutna potreba za promenom boje, položaja, oblika postojećih zuba i u slučaju sprovođenja restauracija oštećenih zuba. Postupku preparacije prethodi detaljan dijagnostički pristup i preoperativna analiza facijalnih, dentalnih i okluzalnih parametara. Konzervativnost postupka preparacije se postiže time što realnu potrebu za uklanjanjem zubnog tkiva determiniše željeni konačni volumen nadoknade. Preparacija se obavlja posebno dizajniranim borerima čija je dubina usecanja u zubno tkivo jasno definisana, kao i fisurnim dijamantskim borerima sa zaobljenim vrhom. Uvek kada je to moguće, preparacija treba da se završi u gleđ i, supragingivalno. Demarkacija je u obliku polužleba. Provera ekstenzivnosti preparacije se obavlja pomoću silikonskog ključa koji je napravljen na osnovu voštanog modela gotove nadoknade. Otiskivanje se vrši jednovremenom tehnikom sa dve viskoznosti otis nog materijala (adicioni silikoni). Nakon preparacije zuba izrađuju se privremene nadoknade, koje do izrade definitivnih keramičkih faseta, ispunjavaju zaštitnu i estetsku ulogu. U laboratorijskoj izradi keramičkih faseta koriste se različite vrste keramike i različiti tehnološki postupci izrade: presujuća tehnologija, tehnika slojevitog slaganja, frezovanje gotovih keramičkih blokova. Pre postupka cementiranja obavezno je probati fasete u ustima pacijenta. Cementiranje se obavlja svetlosno polimerizujućim kompozitnim cementom; prethode mu postupci pripreme kako površine zuba tako i unutrašnje površine keramičke fasete.

U ovom radu opisano je ispitivanje uticaja mastikatornih sila na kvalitet veze između kompozitnog cementa i titanijumskog abatmenta. U okviru ovog rada analizirane su 22 cirkonijum oksidne keramičke nadoknade iz klase sjekutića, očnjaka, premolara i molara vezane za titanijumske abatmente. Nakon završenog opterećenja i potapanja u 5% metilensko plavo obavljeno je presijecanje uzoraka u mezio distalnom smjeru i analiziranje pojave mikrocurenja boje između abatmenta i keramike duž oba aksijalna zida pomoću stereomikroskopa. Prodor boje u odnosu na aksijalni zid je kvantifikovan skalom od 4 stepena (0-3) na sljedeći način. 0 – nema prodora boje; 1 – mikrocurenje do početka prve trećine aksijalnog zida; 2 – mikrocurenje je do početka druge trećine aksijalnog zida; 3 – mikrocurenje je duž cijelog aksijalnog zida. Osam uzoraka je pokazalo mikrocurenje distalno sa prosječnom vrijednošću 1,5 (dva uzorka vrijednosti 3 i jedan uzorak vrijednosti 2), dok je 7 uzoraka pokazalo mikrocurenje sa obje strane (i mezijalno i distalno).

Uvod: Kraniomandibularne disfunkcije (KMD) predstavljene su sveobuhvatnim terminom, koji se odnosi na veliki broj simptoma i kliničkih stanja vezanih za mastikatorne mišiće, temporomandibularne zglobove (TMZ) i pripadajuće strukture glave i vrata. Zbog kompleksnosti, ali i mnoštva kontradiktornosti u stavovima o etiologiji, dijagnostici i terapiji ovih poremećaja, tema su istraživanja u stručnoj i naučnoj literaturi. Zahtevi savremenog društva, kao i tempo koji je nametnut u realizaciji istih, predstavljaju stres za pojedinca, koji dovodi do različitih disfunkcionalnosti i poremećaja u organizmu, među kojima su i pojava KMD. Iako u literaturi postoje neosporni dokazi o povezanosti hroničnog bola i psihosocijalnih faktora kod pacijenata sa KMD, i dalje su potcenjeni ovi faktori, nedovoljno ispitani sa više aspekata, sa nejasno definisanim pristupom i značajem procene njihove zastupljenosti. Kompleksnost ovih poremećaja nameće potrebu postavljanja dijagnostike KMD preciznim individualnim pristupom. U proceni etioloških faktora neophodna je kombinacija dijagnostičkih protokola sa dodatnim dijagnostičkim metodama (algometrija, merenje kortizola uzorkovanjem pljuvačke, vizuelno – analogna skala bola - VAS). Samo takav pristup bi omogućio preciznu dijagnostiku, što je preduslov za buduću pravovremenu i adekvatnu terapiju. Cilj: Utvrditi prisustvo i stepen emocionalnog stresa, kao jednog od osnovnih etioloških uzročnika KMD kod ispitanika eksperimentalne i kontrolne grupe. Utvrditi razlike u pojavi psihosocijalnih faktora kod pacijenata sa KMD i ispitanika bez znakova i simptoma KMD. Verifikovanjem stepena intenziteta hroničnog bola utvrditi njegovu povezanost sa znacima i simptomima depresije i somatizacije kod pacijenata sa KMD. Metode: Uzorak je obuhvatao 100 ispitanika, a dijagnoza KMD je utvrđena po principima dijagnostičkih protokola i kriterijuma za istraživanje kraniomandibularnih disfunkcija (engl. Research Daignostic Criteria for Craniomandibular disorders, RDC/C

Modernu stomatologiju karakteriše ogroman napredak u tehnologiji izrade zubnih nadoknada, ali i pojava velikog broja novih gradivnih materijala. Upoređivanje dva različita materijala pod istim uslovima jedan je od načina za razumevanje različitosti između njih. Poli-etar-etar-keton je polimer koji ima mnogo potencijala u stomatologiji, kao i već uveliko poznata litijum-disilikatna staklo keramika. Ciljevi. Cilj ove doktorske disertacije je bio da se uporede stepen preživljavanja i stepen uspešnosti implantatno-protetske terapije izradom litijum-disilikatnih i poli-etar-etar-keton (PEEK) implantatno nošenih zavrtnjem retiniranih pojedinačnih kruna metodom podeljenih usta, procena estetskih svojstava i zadovoljstva zubnih nadoknada, analiza kvaliteta života subjektivnim tehnikama pacijenata pre i nakon implantatno-protetske terapije, analiza estetskih parametara mekog tkiva i estetskih parametara samih nadoknada od strane terapeuta, procena periimplantatno mekotkivnog zarastanja i periimplantatne koštane resorpcije u različitim opservacionim periodima, merenje vremena potrebnog za izradu i procena jednostavnosti izrade obe vrste nadoknada od strane zubnih tehničara. Materijal i metod. Ovo istraživanje je sprovedeno kao prospektivna randomizovana klinička studija, sa opservacionim periodom od godinu dana, tokom kojeg su u kontrolnim intervalima rezultati analizirani i međusobno poređeni. Celokupno istraživanje sprovedeno je na Klinici za stomatološku protetiku i na Klinici za oralnu hirurgiju Stomatološkog fakulteta Univerziteta u Beogradu. Na ugrađenim implantatima BlueSky®(Bredent, Senden, Nemačka), nakon perioda oseointegracije, izrađene su krunice od PEEK materijala fasetirane kompozitnim materijalima (BioHpp®) i krunice od presovane litijum-disilikatne keramike (Ips e.max press®) u cut-back body formi, fasetirane feldspatnom keramikom. Upoređivanje je izvedeno metodom podeljenih usta litijum-disilikatnih i poli-etar-etar-keton (PEEK) implantatno nošenih zavrtnjem, Expansion of new production technologies characterizes modern dentistry, as well as many new materials on the market. Comparing two materials under the same conditions is the best way for defining differences between them. Polyetheretherketone (PEEK) is a polymer that has many potential uses in dentistry, the same as already well-known lithium disilicate ceramics. Aim. The aim of this doctoral thesis was to compare lithium disilicate and polyetheretherketone (PEEK) implant screw-retained solo crowns using the split-mouth design for analyzing the success and survival rate, the esthetic and restoration satisfaction evaluation by patient subjective techniques, quality of life evaluation, aesthetic soft tissue parameters and aesthetic restoration parameters evaluated by the therapist, evaluation of peri-implant soft tissue healing and peri-implant bone resorption in different observation periods, measuring the time required for the crown production and the simplicity evaluation for production phases between the two observed groups of crowns. Materials and Methods. This study was conducted as a prospective randomized clinical study, with an observation period of one year, during which the results were analyzed and compared with each other at control intervals. The entire research was conducted at the Clinic for Dental Prosthetics and the Clinic for Oral Surgery, School of Dentistry, University of Belgrade. After the implant osseointegration period (BlueSky® (Bredent, Senden, Germany)), crowns were made of PEEK material veneered with composite materials (BioHpp®) and pressed lithium-disilicate ceramics (E.max press®) in cut-back body form veneered with feldspathic ceramic. Comparison of lithium-disilicate and poly-ether-ether-ketone (PEEK) implant-supported screw-retained crowns using split-mouth design was evaluated with subjective and objective parameters. The analyses included patient’s aesthetic assessment and dental restoration satisfaction using visual-analogue scal

Stereooptics method have been successfully used in biomechanical studies of dental models. The aim of this study was to investigate, on the basis of functional deformities, the distribution of occlusal loads on the casts of a partially-edentulous mandible without and with dedicated copings. Precise measurement of strain and displacement of partially-edentulous mandibular control and experimental casts were provided by the digital image correlation method and ARAMIS software. Simulated loads ranged from 0 to 1000 N. Displacements and deformations of abutment teeth within the control cast of a partially-edentulous mandible were 0.48% for incisor without coping, 10.29% for canine without coping, and 6.64% for premolar without coping, and within the experimental cast of a partially-edentulous mandible they were 0.29% for incisor with coping, 7.007% for canine with coping, and 4.98% for premolar with coping. Wilcoxon matched pairs signed ranks sum test was not statistically significant for the majority of the examined parameters, except for the differences between deformations of teeth and copings under pressure p lt = 0.05. When loading the abutment teeth, the distribution of strain through the remaining tooth substance is specific and various. Abutment teeth covered by protective copings are more resistant to loads.

Kompozitni materijali predstavljaju materijal izbora za direktnu i indirektnu izradu i reparaciju zubnih i gingivalnih nadoknada u savremenoj protetici. Iako su mnogo korišćeni, ovi materijali još uvek ne predstavljaju idealnu zamenu za zubna tkiva i gingivu jer, pored brojnih prednosti, imaju i određene nedostatke. Jedan od glavnih nedostataka je promena boje i fluorescencije kompozita prilikom izlaganja različitoj hrani i napicima koji se svakodnevno konzumiraju. Usled prebojavanja estetske nadoknade, moraju se vrlo često korigovati ili zameniti novim. Poslednjih godina, istraživanja su usmerena ka smanjenju razlike u boji između kompozitnih materijala i tvrdih i mekih zubnih tkiva ne samo u momentu izrade već i u funkciji vremena i pronalasku „idealnog“ estetskog materijala. Cilj istraživanja u disertaciji je bio da se ispitaju boja i fluorescencija kompozitnih materijala različite protetske namene i uporede s bojom i fluorescencijom zuba, kao i da se ispita stabilnost boje i fluorescencije kompozitnih materijala. U prvom delu istraživanja su ispitivani komercijalni kompozitni materijali namenjeni direktnoj i indirektnoj izradi i reparaturi zubnih nadoknada i rekonstrukciji veštačke gingive. Kompoziti koji se primenjuju u stomatološkoj protetici i implantologiji potapani su u različitim vremenskim intervalima u svakodnevne često konzumirane napitke: kafa, čaj, crveno vino, gazirani napitak, rastvor za svakodnevno održavanje oralne higijene, destilovana voda, razne vrste piva, energetska pića i prirodni sokovi. Korišćenjem spektrofotometra izmereni su difuzni refleksioni spektri uzoraka, podaci su analizirani u CIEL*a*b* sistemu boja i urađena je PCA (Analiza glavnih komponenata) dobijenih spektara. Merenjima na spektrofluorimetru dobijeni su fluorescentni spektri kompozitnih uzoraka, pomoću kojih su napravljeni konturni grafikoni EEM (ekscitacionoemisione matrice) i izračunat je procenat ukupne promene fluorescencije. Nakon početnih merenja, utvrđena je početna h, Contemporary prosthodontic composite is a material of choice for direct and indirect restorations of the missing tooth structures. Widely used, this material still doesn’t meet all requirements of ideal dental material. One of its main esthetic failures is regarding the change of color and fluorescence, when exposed to daily consumed beverages, leading to the frequent need for restoration replacement. Latest research are conducted towards diminishing the difference between the color of composite and the color of the hard and soft tooth tissues, not only in the moment of placement, but in the long time interval and finding the „ideal“ esthetic material. The goal of this research was to investigate the color and fluorescence of composite materials and tooth structures and to compare it with the color and fluorescence of natural teeth, as well as to investigate the stability of the color and fluorescence of composite materials. In the first part of this research, commercial composite materials made for direct and indirect restorations in prosthodontics and implantology were evaluated. Composite samples made for the different prosthetic purposes were exposed to different beverages – coffee, tea, red wine, carbonated beverage, oral hygiene solution, distilled water, beer, energy drinks, natural juices. Spectrophotometric measurements provided diffuse reflectance spectra which were CIEL*a*b* color analyzed and PCA (Principal Component Analysis) analyzed. Spectrofluorometer provided fluorescent composite spectra from which EEM (excitation-emission) contour plots were made and the percentage of fluorescence decrease was calculated. Initial measurements showed that color and fluorescence were homogenous among tested composite samples. Initial color coordinates, surface roughness, and fluorescence vary among different composite manufacturers even with the same shade selection. According to the results from the first part of the investigation, staining of the composite was mor

Jednoseansni intraoralni CAD-CAM sistemi izvorno predstavljaju grupu digitalnih tehnologija koje omogućavaju izradu zubnih nadokanada tokom jedne posete pacijenta lekaru. Sastavni delovi ovih sitema predstavljaju 3D intraoralni skener, računar sa softverom koji prikuplja 3D prostorno definisane merne tačke i obradjuje ih u trodimenzionalnu sliku virtuelnog radnog modela na kome se dizajnira zubna nadoknada, i prigodna numerički vodjena frez ili neka druga Rapid Prototaiping mašina (numerički kontrolisane mašine za brzu izrdau prototipova). Postupak završne obrade je ordinacijski a cementiranje je pretežno adhezivno. Najvažnije prednosti jednoseansnih sistema i njihovih tehnika izrade zubnih nadoknada su: omogućavanje izrada zubnih nadoknada u jednoj poseti lekaru; skraćene intraoralne faze rada u ordinaciji; veći komfor pacijenta; ponovljivost; faze laboratorijske izrade zubnih nadoknada su u potpunosti ili delimično eliminisane; ekonomski su isplatljivi. Osnovni nedostatak jednoseansnih sistema je otežano ili onemogućeno otiskivanje dublje subgingivalne demarkacije, što utiče na širinu indikacionog polja. Relativni nedostatak predstavlja i potreba za obučenosti operatera.

Keramičke fasete su tanke porcelanske ljuspe trajno, adhezivno cementirane za zubne strukture, menjajući na taj način oblik i/ili boju zuba. Indikaciono polje za njihovu izradu obuhvata promenu boje, oblika, položaja zuba kao i nadoknadu gubitka zubne supstancije različite etiologije. Za izradu KF koriste se silikatne kermike dobijene metodom presovanja, slojevitog slaganja ili frezovanja. U preoperativnoj pripremi važna je odlična komunikacija sa pacijentom, tehničarem i jasno definisanje ciljeva tretmana. Od velike pomoći su dijagnostički wax-up modeli i privremene, kompozitne fasete. Preparacija se obavlja pomoću posebnih DC borera i fisurnih dijamantskih borera sa zaobljenim vrhom. Količina redukcije zubne supstance ne treba da bude ista u svakom kliničkom slučaju već treba da bude vođena željenom debljinom nadoknade. Provera ekstenzivnosti preparacije se vrši brušenjem kroz privremene fasete ili pomoću silikonskog ključa. Demarkacija je oblika polužleba i poželjno je da bude lokalizovana supragingivalno. Otiskivanje se vrši jednovremenom dvofaznom tehnikom pomoću adicionih silikona. Do izrade definitivnih nadoknada, pacijent treba da bude zbrinut privremenim fasetama radi nadoknade funkcije, estetike i zaštite brušenih zuba. Pre cementiranja potrebno je izvršiti probu KF i pripremiti fasete i zub. Cementiranje se vrši LC kompozitnim cementom. Pacijentu je potrebno pružiti savete o ponašanju u periodu nakon cementiranja.

The purpose of this study was to evaluate color adjustment potential (CAP) of resin composites. Two shades of each of eight commercial resin composites and one control shade were evaluated. Visual (color competent observers, controlled conditions) and instrumental color evaluations (spectroradiometer, spectrophotometer) were performed. The data were analyzed by analysis of variance, Fisher's PLSD intervals for comparison of means, and Spearman's rank order correlation. Instrumental color adjustment potential (CAP-I) ranged from - 0.51 to 0.74, and corresponding Fisher's PLSD intervals were 0.1 and 0.05, respectively (p lt 0.0001, power 1.0). Visual color adjustment potential (CAP-V) ranged from 0.10 to 0.78, and corresponding Fisher's PLSD intervals were 0.2 and 0.1, respectively (p lt 0.0001, power 1.0). The greatest overall color shifting between test shades in isolation and the same shades surrounded by control shade were recorded for HRi ENA enamel, followed by Clearfil Majesty ES2. The highest visual CAP (blending) was recorded for Herculite Ultra, HRi ENA enamel, and Clearfil Majesty ES2. Within the limitation of the study, it was found that color adjustment potential (CAP) was composite and shade-dependent. Positive CAP was recorded both instrumentally and visually for majority of composites and shades. Overall, the measured color difference reduction associated with positive CAP was 31%, while the average visual CAP was 43%. Resin composites with pronounced color adjustment potential interact with surrounding dental restorations. Introduced CAP-V and CAP-I were indirect measurements of blending (optical illusion).

Compromised dentition has been suggested to pose a significant risk factor for dementia. It was mainly investigated through insufficient tooth number, disregarding contact between opposing teeth (dental occlusion). The epsilon 4 allele of apolipoprotein (APOE4) is the primary genetic marker for the late onset of Alzheimer's disease (AD). However, APOE4 and dental occlusion have not yet been investigated as possible associated risk factors for AD. The study was aimed to examine the impact of dental status and different APOE gene variants on AD occurrence. Secondly, sociodemographic variables were investigated as factors potentially associated with AD. The case-control study included two groups: 116 patients with AD (according to the NINDS-ADRDA criteria) and 63 controls (Mini-Mental State Examination scores >= 24). The analysis of APOE gene polymorphism was conducted through PCR reaction. Dental examination included recording of number of teeth, presence of fixed or removable dentures, and number of functional tooth units (FTU). Regression analysis was used to investigate the joint effect of the clinical and genetic variables on AD. Results showed that patients with AD were more often carriers of epsilon 3/epsilon 4 genotype and epsilon 4 allele, had lower number of teeth and FTU, and were less likely to be married, live in home, and had less chronic diseases, compared to the controls. Regression analysis showed that presence of APOE4 allele and the number of total FTU remained associated with AD, even when adjusted for age, sex, and level of education. In conclusion, deficient dental occlusion and presence of APOE4 may independently increase risk for AD.

The implementation of intraoral and extraoral computer-aided-design and computer-aided-manufacturing (CAD/CAM) systems in prosthetic dentistry has simplified the procedure, shortened the period of design and manufacture and improved accuracy and aesthetic properties of dental restorations. Three-dimensional (3D) digitisation has become an adequate replacement for conventional dental impressions. The market offers a variety of diverse optical intraoral and extraoral CAD/CAM systems equipped with digitisation devices that are based on different working principles. The main goal of this research is to determine whether precision and accuracy differ among optical digitisation devices. The research includes five high-end devices: Cerec AC, Cerec InEos, Trios, KaVo Everest and Sinergia Scan. The evaluation methodology of the experiment is based on CAD inspection. The results, obtained from accuracy and precision measurements with tolerance levels of 0.01, 0.25 and 0.05 mm, indicate that there is a difference in accuracy and precision between optical digitisation devices based on different working principles.

Background/Aim. There is limited published evidence on the cytotoxicity of 3D printed polymer materials for dentistry applications, despite that they are now widely used in medicine. Stereolithography (SLA) is one of the foremost 3D processes used in 3D printing, yet there are only a small number of resin materials reported to be suitable for medical applications. The aim of this study was to investigate, in vitro, the cytotoxic effect of the 3D printed resin in order to establish the suitability for its usage in dentistry and related medical applications such as surgical dental guides, occlusal splits and orthodontic devices. Methods. To examine the cytotoxicity of the 3D printed polymer-based epoxy resin, Accura® ClearVue™ (3D-Systems, USA), two cell cultures were used: mouse fibroblasts L929, and human lung fibroblasts MRC-5. The cell viability was determined by the Mosmann's colorimetric (MTT) test and the agar diffusion test (ADT). Results. Direct contact of the tested material with the ADT test showed nontoxic effects of tested material in any cell culture. The tested material showed no cytotoxic effect after 3 days of extraction of the eluate by the MTT, but mild cytotoxic effect after 5, 7 and 21 days on both cell lines. The cytotoxicity increased with increasing the time of the eluate extraction. Conclusion. The 3D printed polymer-based epoxy resin, Accura® ClearVue™ (3D-Systems, USA) is considered appropriate for making surgical dental implant guides according to the cytotoxic behavior. According to the mild level of cytotoxicity after the longer extraction periods, there is a need for further evaluation of biocompatibility for its application for the occlusal splints and orthodontic devices., Uvod/Cilj. Malo je objavljenih dokaza o citotoksičnosti 3D štampanih polimernih materijala za upotrebu u stomatologiji, bez obzira na njihovu sve širu primenu u medicini. Stereolitografija (SLA) jedan je od najvažnijih 3D procesa koji se primenjuje za 3D štampu, ali postoji samo Mali broj materijala na bazi smola za koje je dokazano da su pogodni za medicinsku primenu. Cilj ove studije je bio da se ispita, in vitro, citotoksični efekat 3D štampanog polimera kako bi se utvrdila mogućnost za njegovu upotrebu u stomatologiji i srodnim medicinskim oblastima, kao što su hirurške dentalne vođice, okluzalni splintovi i ortodontski aparati. Metode. Da bi se ispitala citotoksičnost 3D štampanog polimera na bazi epoksi smole, Accura® ClearVue ™ (3D-Sistems, USA), korišc'ene su dve c'elijske kulture: fibroblasti miša L929 i humani fibroplasti pluc'a MRC-5. Vijabilnost c'elija utvrđena je Mosmannovim kolorimetrijskim testom (MTT) i testom difuzije agara (ADT). Rezultati. Direktan kontakt testiranog materijala ispitan pomoću ADT pokazao je da materijal nije imao citotoksičan efekat ni na jednu ćelijsku kulturu. Testitrani materijal je imao blag citotoksični efekat posle 5, 7 i 21 dana ekstrakcije eluata primenom MTT na obe ćelijske linije. Citotoksičnost je rasla sa produženjem vremena ekstrakcije eluata. Zaključak. 3D štampani polimer na bazi epoksi smole, Accura® ClearVue ™ (3D-Sistems, USA) se može smatrati pogodnim za izradu hirurških dentalnih implantnih vođica sa tačke gledišta njegovog citotoksičnog uticaja. Zbog pokazanih blagih citotoksičnih efekata nakon dužih ekstrakcionih perioda eluata potrebna su dalja istraživanja u oblasti biokompatibilnosti materijala da bi se taj polimer mogao koristiti za izradu okluzalnih splintova i ortodontskih aparata.

Development and improvement of 3D digitizing systems provide for the ability to digitize a growing number of materials and geometrical forms of greater complexity. This paper presents the application of 3D digitizing system using close range photogrammetry on the upper jaw cast in plaster in order to obtain its 3D model. Because of the low visual characteristics of gypsum, such as color and texture, many questions arise about the possibility of applying this particular method to this type of physical models. In order to overcome bad visual properties of gypsum, this paper analyzes the possibility of the photogrammetry method application supported by the projected light texture which is based on patterns in the form of noise-obtained mathematically modeled functions. In order to determine the selected image for light texture which gives the better results, an experiment was designed and carried out. Only two images were tested. One image is selected based on previous research and the other one was generated by the Matlab function for uniformly distributed random numbers. For validation and a comparative analysis of the results, an object of 3D digitization was generated with and without projected light texture. CAD inspection was applied for the analysis of the obtained 3D digitizing results. 3D model obtained by approved professional optical 3D scanner as a reference was used. The results in this paper confirm better accuracy of 3D models obtained with the use of light textures, but this approach requires additional hardware and setup adjustment for images acquisition.

The paper presents a comparative study of the measuring values of the marginal gap related to the ceramic crowns made by dental CAD/CAM system using the replica technique and SEM. The study was conducted using three experimental groups, which consisted of ceramic crowns manufactured by the Cerec CAD/CAM system. The scanning procedure was carried out using three specialized dental 3D digitization systems from the Cerec family - two types of extraoral optical scanning systems and an intraoral optical scanner. Measurements of the marginal gap were carried out using the replica technique and SEM. The comparison of aggregate values of the marginal gap using the replica technique showed a statistically significant difference between the systems. The measured values of marginal gaps of ceramic crowns using the replica technique were significantly lower compared to those measured by SEM. The results indicate that the choice of technique for measuring the accuracy of ceramic crowns influences the final results of investigation.

Development and improvement of 3D digitization methods in the last forty years, have enabled that virtual impression in dentistry becomes a reality. Unlike conventional impressions, which represent negative copies of prepared teeth and surrounding tissue, 3D digitization collects data on the coordinates of surface points and transfers them into digital form. Various working principles of 3D digitization methods were the reason, that in the framework of this reasearch to invstigate and compare the basic metrological characteristics of selected optical digitization devices. Based on the hypothesis, following goal of investigation were formulated: to establish whether there is a difference in the accuracy and precision between the optical digitization devices where the process of digitization based on various working principles and determine the degree of measurment uncertainty. The basis of this experiment is CAD inspection. CAD inspection was used to measure and analyze deviations between the CAD reference model and experimental CAD models. In this way is possibile to determine the precision and accuracy of the observed optical digital device. The experimental CAD models were generated by 3D digitization of the stone replica using Cerec® AC (Sirona, Germany), Cerec® In Eos Blue (Sirona, Germany), Trios (3 shape AS, Denmark), KaVo Everest (KaVo, Germany) and Sinergia Scan (Nobil - Metal, S.p.A. Italy) surface digitization devices. The CAD master model was generated by 3D digitization of the stone replica, using Atos III Triple Scan surface digitization device. Processing of the measured results included 2D and 3D analysis. The results of 3D analysis showed thet the highest level of precision in the proceeding of digitizing the right half of upper dental arch are present in Sinergia Scan, then follow KaVo Everest, Trios, Cerec®InEos Blue i Cerec®AC devices. The highest level of accuracy in the same procedure have Cerec®InEos Blue, follow the Sinergia Scan, Cerec®AC i K, Razvoj i unapređenje metoda 3D digitalizacije u proteklih četrdeset godina, omogućio je da se ideja o primeni digitalnog otiska u stomatologiji pretvori u stvarnost. Za razliku od konvencionalnog otiska koji predstavlja kopiju zuba i okolnih tkiva u negativu, 3D digitalizacija je postupak u okviru koga se vrši prikupljanje podataka u vidu koordinata – tačaka i obavla njihovo prevođenje u digitalnu formu. Razlike u radnim principima postupaka 3D digitalizacije predstavljale su povod da se u okviru istraživanja ispitaju i uporede osnovne metrološke karakteristike odabranih uređaja za optičku digitalizaciju, koji se primenjuju u stomatološkoj praksi. Na osnovu postavljene hipoteze definisan je osnovni cilj istraživanja: utvrditi da li postoji razlika u preciznosti i tačnosti između uređaja za optičku digitalizaciju kod kojih je postupak digitalizacije zasnovan na različitim radnim principima i na osnovu toga proceniti stepen njihove merne nesigurnosti. Osnovu eksperimenta čini metoda CAD inspekcije, čijom primenom je moguće izvršiti kvantitativnu i kvalitativnu analizu izmerenih odstupanja uzoraka CAD eksperimentalnih modela u odnosu na CAD master model i na taj način utvrdi stepen preciznosti i tačnosti posmatranih uređaja. CAD eksperimentalni uzorci su nastali u postupku digitalizacije osnovnog modela od gipsa pomoću sledećih uređaja: Cerec®AC (Sirona, Germany), Cerec® InEos Blue (Sirona, Germany), Trios (3 shape AS, Denmark), KaVo Everest (KaVo, Germany) i Sinergia Scan (Nobil - Metal, S.p.A. Italy). Digitalizacijom osnovnog modela pomoću industrijskog optičkog uređaja Atos III Triple Scan dobijen je CAD master model. Obrada izmerenih rezultata obuhvatala je 3D i 2D analizu. Rezultati 3D analize prikazuju da je najviši stepen preciznosti uređaja u postupku digitalizacije desne polovine zubnog luka gornje vilice prisutan kod Sinergia Scan, slede KaVo Everest, Trios, Cerec®InEos Blue i Cerec®AC uređaji. Najviši stepen tačnosti u istom postupku ima Cerec®InEos Blue, sl

Uvod Razlike u odgovoru zuba i implantata na opterećenje mogu imati za posledicu niz bioloških i tehničkih komplikacija u uslovima delovanja okluzalnih sila. Cilj rada Cilj ovog rada je da se analizira distribucija opterećenja kod mešovito nošenih mostova sa primenom rezilijentnog TSA abatmenta (Titan Shock Absorber, BoneCare GmbH Germany), kao i konvencionalnog nerezilijentnog abatmenta primenom metode konačnih elemenata (MKE). Metode rada U ovom radu napravljena su dva osnovna 3D modela. Na jednom implantatu i modelu korišćen je standardni nerezilijentni abatment, a na implantatu drugog modela korišćen je rezilijentni TSA abatment. Na virtuelnom modelu su modelirane konture zuba, PDL-a, sluzokože, implantata, kortikalne i spongiozne kosti, abatmenta i suprastrukture. U eksperimentu je korišćena vertikalna sila od 500 N, koja je primenjena u tri različita slučaja aksijalnog opterećenja. Metodom konačnih elemenata izračunavani su potom Fon Mizesovi ekvivalentni naponi u korenu zuba i parodoncijumu, implantatu i periimplantatnom tkivu. Rezultati Na modelu kod koga je primenjen nerezilijentni abatment, maksimalne vrednosti napona i deformacije u sva tri slučaja su registrovane u kortikalnom delu kosti oko zuba i implantata u zavisnosti od napadne tačke sile (maksimalan napon 49,7 MPa). Vrednosti napona i deformacija na modelu sa primenom rezilijentnog TSA abatmenta pokazale su sličnu raspodelu u kosti, međutim ove vrednosti su višestruko manje nego kod modela sa nerezilijentnim abatmentom (maksimalan napon 28,9 MPa). Zaključak Primena rezilijentnog TSA abatmenta dovodi do ravnomernije raspodele napona i deformacije u koštanom tkivu oko zuba i implantata pod dejstvom vertikalnih sila. Izmerene vrednosti su višestruko manje nego na modelu sa nerezilijentnim abatmentom., Introduction Differences between the tooth and implant response to load can lead to many biological and technical implications in the conditions of occlusal forces. Objective The objective of this study was to analyze load distribution in tooth/implant-supported fixed partial dentures with the use of resilient TSA (Titan Shock Absorber, BoneCare GmbH, Augsburg, Germany) abutment and conventional non-resilient abutment using finite element method. Methods This study presents two basic 3D models. For one model a standard non-resilient abutment is used, and on the implant of the second model a resilient TSA abutment is applied. The virtual model contains drawn contours of tooth, mucous membranes, implant, cortical bones and spongiosa, abutment and suprastructure. The experiment used 500 N of vertical force, applied in three different cases of axial load. Calculations of von Mises equivalent stresses of the tooth root and periodontium, implants and peri-implant tissue were made. Results For the model to which a non-resilient abutment is applied, maximum stress values in all three cases are observed in the cortical part of the bone (maximum stress value of 49.7 MPa). Measurements of stress and deformation in the bone tissue in the model with application of the resilient TSA abutment demonstrated similar distribution; however, these values are many times lower than in the model with non-resilient TSA abutment (maximum stress value of 28.9 MPa). Conclusion Application of the resilient TSA abutment results in more equal distribution of stress and deformations in the bone tissue under vertical forces. These values are many times lower than in the model with the non-resilient abutment.

Introduction Differences between the tooth and implant response to load can lead to many biological and technical implications in the conditions of occlusal forces. Objective The objective of this study was to analyze load distribution in tooth/implant-supported fixed partial dentures with the use of resilient TSA (Titan Shock Absorber, BoneCare GmbH, Augsburg, Germany) abutment and conventional non-resilient abutment using finite element method. Methods This study presents two basic 3D models. For one model a standard non-resilient abutment is used, and on the implant of the second model a resilient TSA abutment is applied. The virtual model contains drawn contours of tooth, mucous membranes, implant, cortical bones and spongiosa, abutment and suprastructure. The experiment used 500 N of vertical force, applied in three different cases of axial load. Calculations of von Mises equivalent stresses of the tooth root and periodontium, implants and peri-implant tissue were made. Results For the model to which a non-resilient abutment is applied, maximum stress values in all three cases are observed in the cortical part of the bone (maximum stress value of 49.7 MPa). Measurements of stress and deformation in the bone tissue in the model with application of the resilient TSA abutment demonstrated similar distribution; however, these values are many times lower than in the model with non-resilient TSA abutment (maximum stress value of 28.9 MPa). Conclusion Application of the resilient TSA abutment results in more equal distribution of stress and deformations in the bone tissue under vertical forces. These values are many times lower than in the model with the non-resilient abutment., Uvod Razlike u odgovoru zuba i implantata na opterećenje mogu imati za posledicu niz bioloških i tehničkih komplikacija u uslovima delovanja okluzalnih sila. Cilj rada Cilj ovog rada je da se analizira distribucija opterećenja kod mešovito nošenih mostova sa primenom rezilijentnog TSA abatmenta (Titan Shock Absorber, BoneCare GmbH Germany), kao i konvencionalnog nerezilijentnog abatmenta primenom metode konačnih elemenata (MKE). Metode rada U ovom radu napravljena su dva osnovna 3D modela. Na jednom implantatu i modelu korišćen je standardni nerezilijentni abatment, a na implantatu drugog modela korišćen je rezilijentni TSA abatment. Na virtuelnom modelu su modelirane konture zuba, PDL-a, sluzokože, implantata, kortikalne i spongiozne kosti, abatmenta i suprastrukture. U eksperimentu je korišćena vertikalna sila od 500 N, koja je primenjena u tri različita slučaja aksijalnog opterećenja. Metodom konačnih elemenata izračunavani su potom Fon Mizesovi ekvivalentni naponi u korenu zuba i parodoncijumu, implantatu i periimplantatnom tkivu. Rezultati Na modelu kod koga je primenjen nerezilijentni abatment, maksimalne vrednosti napona i deformacije u sva tri slučaja su registrovane u kortikalnom delu kosti oko zuba i implantata u zavisnosti od napadne tačke sile (maksimalan napon 49,7 MPa). Vrednosti napona i deformacija na modelu sa primenom rezilijentnog TSA abatmenta pokazale su sličnu raspodelu u kosti, međutim ove vrednosti su višestruko manje nego kod modela sa nerezilijentnim abatmentom (maksimalan napon 28,9 MPa). Zaključak Primena rezilijentnog TSA abatmenta dovodi do ravnomernije raspodele napona i deformacije u koštanom tkivu oko zuba i implantata pod dejstvom vertikalnih sila. Izmerene vrednosti su višestruko manje nego na modelu sa nerezilijentnim abatmentom.

Background/Aim. Dental impressions present a negative imprint of intraoral tissues of a patient which is, by pouring in gypsum, transferred extraorally on the working cast. Casting an accurate and precise working cast presents the first and very important step, since each of the following stages contributes to the overall error of the production process, which can lead to inadequately fitting dental restorations. The aim of this study was to promote and test a new model and technique for in vitro evaluation of the dental impression accuracy, as well as to asses the dimensional stability of impression material depending on the material bulk, and its effect on the accuracy of working casts. Methods. Impressions were made by the monophasic technique using the experimental master model. Custom trays with spacing of 1, 2 and 3 mm were constructed by rapid prototyping. The overall of 10 impressions were made with each custom tray. Working casts were made with gypsum type IV. Measurement of working casts was done 24 h later using a coordinate measuring machine. Results. The obtained results show that the working casts of all the three custom trays were in most cases significantly different in the transversal and sagittal planes in relation to the master model. The height of abutments was mainly unaffected. The degree of convergence showed certain significance in all the three custom trays, most pronounced in the tray with 3 mm spacing. Conclusion. The impression material bulk of 1-3 mm could provide accurate working casts when using the monophasic impression technique. The increase of the distance between abutment teeth influences the accuracy of working casts depending on the material bulk., Uvod/Cilj. Otisak predstavlja negativ intraoralnih tkiva, čijim se izlivanjem u gipsu njihova morfologija prenosi ekstraoralno na budući radni model. Sa laboratorijskog aspekta izrade zubnih nadoknada, izlivanje tačnog i preciznog radnog modela predstavlja prvi i veoma bitan korak, pošto svaka sledeća faza doprinosi daljem povećanju greške tokom izrade, što za krajnji ishod može imati neodgovarajuću zubnu nadoknadu. Cilj istraživanja bio je da se ispitaju novi model i tehnika za in vitro procenu preciznosti zubnih otisaka, kao i da se odredi uticaj količine otisnog materijala na dimenzionu stabilnost otisaka i preciznost izrade radnih modela. Metode. Za uzimanje otisaka korišćena je monofazna tehnika otiskivanja. Individualne kašike sa međuprostorom od 1, 2 i 3 mm napravljene su aditivnom tehnologijom za brzu izradu prototipova. Sa svakom kašikom napravljeno je po 10 otisaka. Radni modeli izlivani su u gipsu tipa IV. Merenje radnih modela vršeno je nakon 24 sata na koordinatnoj mernoj mašini. Rezultati. Rezultati pokazuju da radni modeli napravljeni pomoću sve tri individulane kašike u transverzalnoj i sagitalnoj ravni značajno odstupaju od glavnog dela modela. Visina patrljaka je u većini slučajeva bila kao na glavnom modelu. Stepen konvergencije pokazao je određena odstupanja samo kod kašike sa međuprostorom od 3 mm. Zaključak. Monofazna tehnika otiskivanja i otisni materijal debljine od 1 do 3 mm obezbeđuju izradu preciznih radnih modela. Rastojanje između zubnih patrljaka utiče na preciznost izrade radnih modela u zavisnosti od količine otisnog materijala.

The paper presents some aspects of the novel integrated system, procedure for fabrication of metal substructure of metal-ceramic crowns. The results been shown that the CAD/CAE/RP technology integration presented in this paper can be fully applied to casting metal substructures. The substructure fabricated in this way, confirm the reduction of the total manufacturing time, with an increase in the percentage of high quality castings that use integrated system.