Izbor cementa za fiksiranje nadoknada na implantatima

Introduction When intraocclusal space is long enough, and patient has high aesthetic demands, cementing implant restoration is the proper choice. The aim of this study was to assess retentive forces of different cements used for fixing restoration to implant abutment. Material and method the separation forces were measured between restorations and abutments that were screw retained to the implant replica. The restorations were casted from Co-Cr-Mo alloy. They were cemented to abutments with five different types of cements (composite resin, glass-ionomer, zinc-polycarboxylate, zinc-phosphate and temporary cement). Each cement represented one group and each group included seven samples. Results Composite resin, glass-ionomer and zinc-polycarboxylate cements showed similar values of retentive forces (256-275 N), while zinc-phosphate cements had slightly lower value (174 N). Temporary cement showed significantly lower value of retentive force (59N). All cements for permanent bonding showed almost the same separation nature. By slow loading, the stress develops, leading to slightly stretched cement and as a consequence, sudden break of cement. Temporary cements also develop stress when slowly loaded, which firstly leads to stretching of cement, and then slight detachment from the implant replica. Conclusion Temporary cement has the lowest retentive force and is suitable for temporary bonding. Composite resin, glass-ionomer, zinc-polycarboxylate and zinc-phosphate cements have high retentive force, and they can be used for permanent cementation of restoration to abutment. Due to the high values of separation force, and other positive characteristics, composite resin should be cement of choice for bonding restorations to implant abutments.Uvod Kod dovoljno velikog međuviličnog prostora i kod estetski zahtevnih pacijenata fiksiranje zubne nadoknade na implantatima cementom je metoda izbora. Cilj rada je da se na osnovu merenja sile razdvajanja zubne nadoknade od nosača nadoknade, cementirane različitim cementima, utvrde vrednosti retencionih sila za različite vrste cemenata. Metode Merena je sila razdvajanja nadoknade od nosača nadoknade, koji je fiksiran zavrtnjem za repliku implantata. Zubne nadoknade izlivene su od Co-Cr legure. Nadoknade su cementirane za nosače nadoknada sa pet različitih cemenata. Svaka vrsta cementa predstavljala je posebnu grupu. Merenja svake grupe su obavljana na sedam uzoraka. Rezultati Kompozitni, glas-jonomerni i karboksilatni cementi su pokazali približno iste vrednosti retencione sile (256-275 N), dok su cink-fosfatni cementi imali nešto manju retencionu silu (174 N). Privremeni cementi su pokazali značajno nižu retencionu silu (59 N). Svi cementi za trajno vezivanje su pokazivali gotovo istovetnu prirodu razdvajanja. Pri postepenom opterećenju razvijaju se naponi u cementu koji dovode do neznatnog istezanja cementnog filma i naglog loma cementa. Pri postepenom opterećenju privremeni cementi razvijaju napone koji prvo dovode do istezanja cementnog filma, a zatim do laganog odvajanja od replike implantata. Zaključak Privremeni cementi imaju najmanju retencionu silu i pogodni su za privremena cementiranja. Kompozitni, glas-jonomerni, karboksilatni i cink-fosfatni cementi daju veliku retencionu silu koja može trajno fiksirati zubnu nadoknadu za nosač implantata. Zbog velike sile razdvajanja, ali i zbog poznatih dobrih osobina, kompozitnim cementima treba dati prednost u cementiranju zubnih nadoknada na implantatima

The fourth industrial revolution's impact on dentistry

Uvod I najveći vizionari nisu mogli da pretpostave kojom brzinom će stomatološka struka i nauka prihvatiti koncept četvrte industrijske revolucije. Po obimu i složenosti ova transformacija je veća od svih do sada poznatih i u literaturi je opisana kao Dentistry 4.0. Digitalna revolucija je stomatologiji omogućila da gotovo sve kliničke i laboratorijske procedure mogu biti podržane digitalnim tehnologijama. Cilj ovog rada je razumevanje uloge četvrte industrijske revolucije u stomatologiji. Metode Pretraživanje baze Medline izvršeno je putem baza podataka PubMed i Google Scholar za termine "četvrta industrijska revolucija", "digitalna stomatologija", "stomatologija 4.0", "CAD-CAM". Takođe su korišćene opcije "srodnih članaka" uz dodatno ručno pretraživanje preglednih članaka i relevantnih tekstova. Rezultati U radu su opisane najčešće dijagnostičke i terapijske procedure koje su podržane digitalnim tehnologijama. Zaključak Sofisticirane tehnologije četvrte industrijske revolucije dovele su do brže i preciznije dijagnoze oralnih oboljenja. Kliničke procedure postaju jednostavnije, preciznije i predvidljivije za lekara, a komfornije za pacijenta. Dugoročno, tu su i ekonomske uštede i očuvanje životne sredine.Introduction Even the greatest visionaries could not have guessed at what speed the profession and science of dentistry would accept the concept of the Fourth Industrial Revolution. In terms of its scale and complexity, this transformation has been greater than any known before and it has been described in the literature as Dentistry 4.0. The digital revolution in dentistry has allowed for nearly all clinical and laboratory procedures to be supported by digital technologies. The aim of this paper is to understand the role of Industry 4.0 in the profession of dentistry and identify its research status today and in the future. Methods An electronic search of Medline literature was performed via PubMed and Google Scholar databases with the terms "fourth industrial revolution," "digital dentistry," "dentistry 4.0," "CAD-CAM." The option "related articles" was also utilized as well as an additional manual search of review articles and the most relevant papers. Results The paper describes the most frequently used diagnostic and therapeutic procedures supported by digital technologies. Conclusion The sophisticated technologies of the Fourth Industrial Revolution have led to more rapid and precise diagnoses of oral diseases. Clinical procedures have become easier, more precise and predictable to the dentist, and more comfortable to the patient. The long-term benefits also include financial savings and environmental protection

The fourth industrial revolution's impact on dentistry

Uvod I najveći vizionari nisu mogli da pretpostave kojom brzinom će stomatološka struka i nauka prihvatiti koncept četvrte industrijske revolucije. Po obimu i složenosti ova transformacija je veća od svih do sada poznatih i u literaturi je opisana kao Dentistry 4.0. Digitalna revolucija je stomatologiji omogućila da gotovo sve kliničke i laboratorijske procedure mogu biti podržane digitalnim tehnologijama. Cilj ovog rada je razumevanje uloge četvrte industrijske revolucije u stomatologiji. Metode Pretraživanje baze Medline izvršeno je putem baza podataka PubMed i Google Scholar za termine "četvrta industrijska revolucija", "digitalna stomatologija", "stomatologija 4.0", "CAD-CAM". Takođe su korišćene opcije "srodnih članaka" uz dodatno ručno pretraživanje preglednih članaka i relevantnih tekstova. Rezultati U radu su opisane najčešće dijagnostičke i terapijske procedure koje su podržane digitalnim tehnologijama. Zaključak Sofisticirane tehnologije četvrte industrijske revolucije dovele su do brže i preciznije dijagnoze oralnih oboljenja. Kliničke procedure postaju jednostavnije, preciznije i predvidljivije za lekara, a komfornije za pacijenta. Dugoročno, tu su i ekonomske uštede i očuvanje životne sredine.Introduction Even the greatest visionaries could not have guessed at what speed the profession and science of dentistry would accept the concept of the Fourth Industrial Revolution. In terms of its scale and complexity, this transformation has been greater than any known before and it has been described in the literature as Dentistry 4.0. The digital revolution in dentistry has allowed for nearly all clinical and laboratory procedures to be supported by digital technologies. The aim of this paper is to understand the role of Industry 4.0 in the profession of dentistry and identify its research status today and in the future. Methods An electronic search of Medline literature was performed via PubMed and Google Scholar databases with the terms "fourth industrial revolution," "digital dentistry," "dentistry 4.0," "CAD-CAM." The option "related articles" was also utilized as well as an additional manual search of review articles and the most relevant papers. Results The paper describes the most frequently used diagnostic and therapeutic procedures supported by digital technologies. Conclusion The sophisticated technologies of the Fourth Industrial Revolution have led to more rapid and precise diagnoses of oral diseases. Clinical procedures have become easier, more precise and predictable to the dentist, and more comfortable to the patient. The long-term benefits also include financial savings and environmental protection

Selektivno lasersko topljenje i sinterovanje dentalne legure kobalt-hrom

Introduction/Objective the objective of this paper is to describe the microstructure and mechanical properties of sintered Co-Cr alloy and to emphasize its advantages and disadvantages with respect to the microstructure and mechanical properties of cast Co-Cr alloy. Methods Base Co-Cr alloy, EOSint M EOS Co-Cr SP2 (EOS GmbH, Munch, Germany), was used for the purpose of this research as the base material for sintering metal structures of metal-ceramic restorations. Metal sintering was conducted by using EOSint M 280 device of German origin in a stream of neutral gas - argon. After that, the alloy was heated over a period of 20 minutes at the temperature of 800°C. The chemical composition of the alloy was determined by energy dispersive spectroscopy. Microstructure of the tested alloy samples was examined under an optical metallographic and scanning electron microscope. Physical and mechanical properties were measured in a universal testing machine. The samples were prepared according to the standard ISO 527-1:1993. Results Chemical composition of the sintered Co-Cr alloy, determined by applying energy dispersive spectroscopy, indicated the same qualitative but different quantitative composition compared to cast Co-Cr alloys. The microstructure of the sintered Co-Cr alloy is lamellar in nature, with two dominant phases: ξ-Co and/or ξ-Cr (fcc - face-centered cubic) and γ-Co (hcp - hexagonal close-packed). Mechanical properties of the Co-Cr alloy obtained by applying selective laser melting technology compared to the cast Co-Cr alloy are superior or approximately the same. Conclusion Selective laser melting of the Co-Cr alloy is a good example of new technologies based on digitization. Together with other digitized procedures, this technology is an introduction to a new era in dentistry popularly called Dentistry 4.0. The advantages of the selective laser melting technology with respect to the conventional technology of casting Co-Cr alloy metal structures are precise metal structure fitting and eco-friendly technology.Uvod/Cilj Cilj rada je opisati mikrostrukturu i mehaničke karakteristike sinterovane legure Co-Cr i istaći njene prednosti i mane u odnosu na mikrostrukturu i mehaničke karakteristike livene legure Co-Cr. Metode U istraživanju je korišćena bazna legura Co-Cr, Eosint M EOS Co-Cr SP2 (EOS GmbH, Minhen, Nemačka) za sinterovanje metalnih konstrukcija metalokeramičkih nadoknada. Sinterovanje metala je obavljeno na aparatu EOSint M 280 u struji neutralnog gasa argona. Nakon toga legura je žarena 20 minuta na temperaturi od 800° C. Hemijski sastav legure određivan je energodisperzivnom spektroskopijom. Mikrostruktura ispitivanih uzoraka legure posmatrana je na optičkom metalografskom i elektronskom skenirajućem mikroskopu. Fizičko-mehaničke karakteristike merene su na univerzalnoj kidalici. Uzorci su pripremani prema standardu ISO 527-1:1993. Rezultati Hemijski sastav uzoraka sinterovane legure CoCr pokazao je isti kvalitativan ali različit kvantitativan sastav u odnosu na legure Co-Cr za livenje. Mikrostruktura sinterovane legure Co-Cr je lamelarne prirode, u kojoj dominiraju dve faze: e-Co i/ili e-Cr (fcc - face-centred cubic) i g-Co (hcp - hexagonal close-packed). U poređenju sa livenom legurom Co-Cr, mehaničke karakteristike sinterovane legure Co-Cr su bolje ili približno iste. Zaključak Selektivno lasersko topljenje legure Co-Cr je dobar primer novih tehnologija zasnovanih na digitalizaciji. Zajedno sa drugim digitalizovanim procedurama koje prethode, ova tehnologija je predvorje novoj eri u stomatologiji, popularno nazvanoj Dentistry 4.0. Prednosti tehnologije selektivnog laserskog topljenja u odnosu na tehnologiju konvencionalnog livenja metalnih konstrukcija od legure Co-Cr su preciznost naleganja metalne konstrukcije i čista tehnologija

Protokoli u klasifikaciji krezubosti

This paper shall discuss the importance of protocol application in modern dentistry. Literature data that include recommendations and consensuses in dental practice point out to their presence in available literature, printed papers, reviewed journals and supplements in the form of expert group conclusions. It should be noted that the protocols most commonly rely on valid postulates of different branches of medicine, supported by specific conditions of the environment in which they are implemented. Additionally, in our settings, applicable dentistry protocols are the result of requirements that institutions and practices should fulfill according to renewable accreditation, as well as following recommendations given in the good clinical practice guidelines with different binding obligations levels. Certain protocols offer therapeutic modalities categorized into classes intended to help users to select appropriate treatments. The second part of this paper shall address one such protocol which classifies partially edentulous patients. The emphasis is on the partial edentulism classification recommended by The American College of Prosthodontists (ACP), which relies on four diagnostic criteria essential for therapeutic decision. Edentulous areas location and extent, abutment teeth health, occlusion model, and residual ridge characteristics represent the parameters which have defined the four classes of partial edentulism of different complexity. In this way, comprehensive approach to the clinical status of the patients has, for the first time been offered to the dental practitioners assuring, among others, higher uniformity of professional attitudes in selection of therapeutic modalities.U radu se diskutuje o značaju primene protokola u savremenoj stomatologiji. Literaturni podaci koji obuhvataju preporuke i konsenzuse u stomatološkoj praksi govore o njihovoj prisutnosti u dostupnim knjigama, štampanim radovima u recenziranim časopisima, i dodacima časopisa kao zaključci ekspertskih grupa. Treba primetiti da su protokoli najčešće oslonjeni na validne postulate različitih medicinskih grana, pomognuti specifičnim uslovima sredine u koju se implementiraju. Dodatno, u našim uslovima, protokoli u stomatologiji su rezultat zahteva koje institucije i prakse moraju da ispunjavaju shodno obnovljivoj akreditaciji, kao i poštovanja preporuka koje su date u vodičima dobre kliničke prakse različitog nivoa obaveznosti. Pojedini protokoli nude terapijske modalitete koji se kategorizuju u klase, pomažući korisnicima u izboru pravog tretmana. O jednom od takvih protokola koji klasifikuje krezube pacijente govori drugi deo rada. Akcenat je na primeni klasifikacije krezubosti koju je preporučio Američki koledž protetičara, a koja se oslanja na četiri dijagnostička kriterijuma, bitna za terapijsku odluku. Lokalizacija i veličina bezubih polja, stanje zdravlja zuba nosača, model okluzije i karakteristike rezidualnog grebena su parametri koji su definisali četiri klase krezubosti različite složenosti. Tako je, prvi put, stomatološkoj praksi ponuđen ozbiljan, sveobuhvatni pristup kliničkom statusu bolesnika, koji obezbeđuje, između ostalog, i uniformnije stručne stavove u izboru terapijskih modaliteta

Main criteria for models of excellence in health care

Business excellence models have a long history of development of sixty years. Today, the business excellence model can be essentially classified as world’s most famous models/awards for excellence (Japanese, American and European), the most popular national models of excellence (the Australian, British, German, French), as well as models of excellence companies (Siemens, Philips, Toyota). In the world today there are about 120 models of excellence. The best way to improve quality of health organizations that have systems of quality management is by application of the concept of total quality (TQM). This approach ensures the improvement of overall performance of health organizations, primarily the internal organization including management, resources, processes and human resources, health services and performance of business results. The market requires high quality products and services to improve the quality of life, or TQM excellence models in all areas of social subjects operations. It is a process that never ends, and knowing the nature of man who was never satisfied with achieved, that is main driving force for social development. We are witnesses today that some countries are introducing awards to organizations which succeeded in implementation of TQM and models of excellence for quality achievement. The development of a model of business excellence (BE) for dental health care is the main subject of the current study. The aim of this study is to present and analyze the existing criteria for product excellence and based on that, to define criteria for models of excellence for dental health care in Serbia

Using historical aerial photography for monitoring of environment changes: a case study of Bovan Lake, Eastern Serbia

Useful and important information for the spatial, ecological, and many other changes in the living environment may be obtained using the analysis of historical aerial photography, with comparison to contemporary imagery. This method provides the ability to determine the state of elements of the space over a long period, encompassing the time when it was not possible to acquire the data from satellite imagery or some other contemporary sources. Aerial images are suitable for mapping spatial phenomena with relatively limited spatial distribution because they possess a high level of details and low spatial coverage. With a comparative analysis of aerial imagery from the past, contemporary aerial imagery, and other sources of aerial imagery, we can obtain information about the nature and trends of the observed phenomena as well as directions of future actions, considering changes detected in the environment, whether they are preventive or corrective in nature. This paper gives the methodological framework for the appliance of the existing knowledge from various fields, intending to use historical aerial photography for monitoring of environmental changes of the Bovan Lake in Eastern Serbia

Prediction of Pest Insect Appearance Using Sensors and Machine Learning

The appearance of pest insects can lead to a loss in yield if farmers do not respond in a timely manner to suppress their spread. Occurrences and numbers of insects can be monitored through insect traps, which include their permanent touring and checking of their condition. Another more efficient way is to set up sensor devices with a camera at the traps that will photograph the traps and forward the images to the Internet, where the pest insect’s appearance will be predicted by image analysis. Weather conditions, temperature and relative humidity are the parameters that affect the appearance of some pests, such as Helicoverpa armigera. This paper presents a model of machine learning that can predict the appearance of insects during a season on a daily basis, taking into account the air temperature and relative humidity. Several machine learning algorithms for classification were applied and their accuracy for the prediction of insect occurrence was presented (up to 76.5%). Since the data used for testing were given in chronological order according to the days when the measurement was performed, the existing model was expanded to take into account the periods of three and five days. The extended method showed better accuracy of prediction and a lower percentage of false detections. In the case of a period of five days, the accuracy of the affected detections was 86.3%, while the percentage of false detections was 11%. The proposed model of machine learning can help farmers to detect the occurrence of pests and save the time and resources needed to check the fields

Okluzalni splint - alternativa u terapiji bolesnika sa temporomandibularnim disfunkcijama

Introduction/Objective The pain that originates from musculoskeletal structures of the mastication system is one of the symptoms belonging to the category of temporomandibular disorders or temporomandibular dysfunction (TMD). The objective of the research was to evaluate the effect of therapy with stabilizing occlusal splint in the control of painful symptoms of TMD in comparison with the effect of drug therapy. Methods Using standard Research Diagnostic Criteria for Temporomandibular Disorders diagnostic protocol proposed by Dworkin and LeResche, a group of 44 patients with painful TMD was included. The patients were divided into three treatment groups by random selection. The first group was treated with stabilization occlusal splint for a period of one month. In the two control groups, therapy with non-steroidal anti-inflammatory drug ibuprofen (Brufen, Mylan, Canonsburg, PA, USA) or a combination therapy of ibuprofen and diazepam, a medication from the benzodiazepine family (Diazepam, Hemofarm, Vršac, Serbia) was carried out over a period of three weeks. In order to assess the effects of the therapy with stabilizing occlusal splint and the drug therapy, before and after the therapy, pain intensity measurements were performed with visual analogue scale and digital pressure algometer. Results A significant reduction in the intensity of painful symptoms was achieved in all three therapeutic groups. No significant differences in the effectiveness of pain reduction between the proposed therapeutic modalities were noted. Conclusion The obtained results confirm that the therapy with stabilization occlusal splint is a valid procedure in the reduction of pain in patients with TMD.Uvod/Cilj Bol porekla mišićno-skeletnih struktura mastikatornog sistema predstavlja jedan od simptoma koji pripadaju kategoriji temporomandibularnih poremećaja ili temporomandibularnih disfunkcija (TMD). Cilj istraživanja je bio da se proceni efekat terapije stabilizacionim okluzalnim splintom u kontroli bolnih simptoma TMD u poređenju sa efektom terapije lekovima. Metode Korišćenjem standardnog dijagnostičkog protokola (RDC/TMD) predloženog od strane Dvorkina i Lerešea, izdvojena je grupa od 44 bolesnika sa bolnim temporomandibularnim disfunkcijama. Bolesnici su podeljeni u tri terapijske grupe slučajnim izborom. Prva grupa je podvrgnuta terapiji stabilizacionim okluzalnim splintom u periodu od mesec dana. U dve kontrolne grupe je sprovedena terapija nesteroidnim antiinflamatornim lekom ibuprofenom (brufen, Mylan) ili kombinacijom ibuprofena i leka iz grupe benzodiazepina - diazepama (diazepam, Hemofarm) u periodu od tri nedelje. U cilju procene efekata terapije stabilizacionim okluzalnim splintom i terapije lekovima, pre i posle sprovedene terapije izvedena su merenja intenziteta bola vizuelnom analognom skalom i digitalnim pritisnim algometrom. Rezultati U sve tri terapijske grupe postignuto je značajno smanjenje intenziteta bolnih simptoma. Nisu zabeležene značajne razlike u uspešnosti smanjenja bola između predloženih terapijskih modaliteta. Zaključak Dobijeni rezultati potvrđuju da je terapija stabilizacionim okluzalnim splintom validna procedura u smanjenju bola kod bolesnika sa TMD

E-PLANE WAVEGUIDE BANDSTOP FILTER WITH DOUBLE SIDED PRINTED-CIRCUIT INSERT

In this paper a novel design of an E-plane bandstop waveguide filter with a double-sided printed-circuit insert is presented. Split-ring resonators are used as the resonating elements to obtain the bandstop response. The amplitude response of the waveguide resonator with a single resonating element on the insert is analyzed for various dimensions and positions of the split-ring resonator. The coupling between two resonators on the insert, in terms of their mutual distance, is considered as a next step to the filter design. Various positions of the resonators are considered, including the case with the resonators on the different sides of the insert, which is of interest for the proposed filter design. Finally, a third-order bandstop filter with a double-sided printed-circuit insert, operating in the X-frequency band, is introduced. The filter response is analyzed for various distances between the resonators and for various positions of the resonator printed on the other side of the insert. Proposed filter design is simple, providing for the accurate fabrication, miniaturization and possibility to relatively easy obtain multi-band response, using resonators with different resonant frequencies on the different sides of the insert