Most Frequent Reasons of Failure in Implantoprosthetic Therapy

Želja djelomično ozubljenih pacijenata za što većom udobnošću i estetikom u protetičkoj terapiji često je u vezi s ugradnjom usadaka. Usadak zamjenjuje ili nadopunjuje prirodni zub kao nosač fiksnog ili mobilnoga protetičkog rada. Zato je implantologija protetički orijentirana disciplina stomatologije u kojoj protetičar vodi plan usadnje i snosi odgovornost za provedenu IP terapiju koju primarno ostvaruje u suradnji s kirurgom, a vrlo često i u timu s parodontologom i ortodontom. Svima je pritom cilj osigurati pacijentu što bolju estetsku i funkcijsku sanaciju te postići optimalnu funkcijsku trajnost IP terapije. Zbog toga je opravdano govoriti o implantološkoj protetici. Moguće komplikacije u vezi su s pojedinim dijelovima implantatnoga sustava, a mogu nastati kliničkim radom ili su u vezi sa samim pacijentom. Svrha je rada prikazati temeljem kliničkih slučajeva najčešće pogrješke koje su uzrokom nezadovoljavajućih estetskih razultata: od izbora vrste i veličine usatka, do smjera i dubine ugradnje, od ne uzimanja u obzir stanja susjednih zuba, parodonta, koštane podloge i postojećih protetičkih radova do loše suradnje pacijenata na održavanju optimalnih higijenskih i statičkih uvjeta.The wish of partially edentulous patients for maximum comfort and aesthetics in prosthetic therapy is frequently connected with the insertion of an implant. The implant replaces or restores the natural tooth as the abutment of a fixed or mobile prosthetic device. Thus implantology is a prosthetically oriented discipline of dental medicine where the prosthodontist supervises a plan of implantation and is responsible for carrying out IP therapy, which is primarily realised in cooperation with a surgeon, and very often also in a team with a periodontologist and orthodontist. The mutual aim is maximal aesthetic and functional treatment of the patient and optimal functional durability of the IP therapy. It is, therefore, justifiable to speak of implantological prosthetics. Possible complications are connected with certain parts of the implantation system, and can arise in clinical work or are connected with the patient himself. The aim of the study was to show, based on clinical cases, the most frequent mistakes which lead to unsatisfactory aesthetic results; from the choice of type and size of implant to the direction and depth of insertion; disregard for the condition of adjacent teeth, periodontium, bone base and existing prosthetic devices, to bad patient cooperation, with regard to the maintenance of optimal hygienic and structural conditions

Influence of heat treatment on the silver-palladium alloy microstructure

U pravilu dentalne legure, pa čak ni one plemenite, nisu homogene u lijevanom stanju. Da bi se osigurao dobar odljev trebalo je pronaći optimalnu temperaturu lijevanja i dodatnu toplinsku obradu koja će omogućiti da se odljevak homogenizira te tako pređe u stanje kemijske inertnosti u biološkom mediju. Nizom pokusa lijevanja, homogeniziranja i precipitiranja postigao se optimalni režim dovođenja Ag-Pd legure na razinu tvrdoće cakline prirodnog zuba (HV 0,1 = 330) a koji se sastoji od sljedećih parametara: lijevanje sa 1100— 1150°C, homogenizacije pri 850° tijekom 20 minuta i gašenje u vodi i precipitacije pri 350°C kroz 20 minuta.Cast dental alloys, even those made of precious metals, are not homogeneous. In order to ensure a high-quality cast, it was necessary to determine optimal casting temperature and additional heat treatment to allow for homogenization of the cast in the microarea of the dendritic structure to occur which, in turn, implies chemical inertia of the metal construction to the organic medium of the mouth. A number of melting, homogenizing and aging tests showed the optimal regimen for bringing an Ag-Pd alloy to the level of hardness of the tooth enamel (about 330 HV 0.1) to consist of a technological treatment involving the following procedures: casting at 1100— 1150°C, homogenization at 850°C, quenching in water and 20-min precipitation at 350°C

Zirconium Oxide Ceramics in Prosthodontics

Keramički materijali opravdavaju sve češću uporabu u restauraciji oštećenoga žvačnog sustava. »isti keramički sustavi rabe se u izradbi inleja, krunica i mostova manjih raspona. Cirkonijev dioksid je poznat polimorf. Dodatkom magnezijeva ili itrijeva oksida u određenom postotku, ZrO2 je potpuno ili djelomično stabiliziran i time je omogućena njegova uporaba u stomatološkoj protetici. Tetragonski cirkonski polikristal (TZP) stabiliziran s 3mol% itrija ima izvanredna mehanička i estetska svojstva i ima sve veću uporabu u restauraciji endodontski saniranih zuba, izradbi krunica i mostova CAD/CAM sustavom. Očekivati je da će taj keramički materijal nadomjestiti kovinsko-keramičke nadomjestke i u sanaciji gubitka većega broja zuba.Dental ceramics justifies more frequent use in prosthetic restoration of damaged dental status. Inlays, crowns and three-unit bridges have been made of all-ceramic system. Zirconia dioxide is a well- known polymorph. The addition of stabilising oxides like MgO, Y2O3 to pure zirconia, makes it completely or partially stabilized zirconia which enables use in prosthodontics. Tetragonal Zirconia Polycrystals (TZP) stabilized with 3mol % yttria, has excellent mechanical and esthetical properties. Fixed prosthetic appliances of this ceramic have been made using CAD/CAM techniques. It can be expected that zirconium oxide ceramics will replace metal-ceramics in restorations that require high strength

Guided Bone Regeneration in Dental Implant Treatment - a Case Report

Gubitak prednjih zuba posljedica je patoloških procesa, retenecije zuba (najčešće gornjeg očnjaka), posljedica traume (avulzija ili fraktura korijena) ili nedostatka zubnoga zametka (najčešće gornjega drugog sjekutića). Takvi slučajevi mogu se riješavati ortodontski (zatvaranjem nastaloga prostora), protetski (različitim mostnim konstrukcijama) ili implantoprotetskom rehabilitacijom. Nedostatak ortodontske terapije dugotrajna je rehabilitacija i česti estetski nedostatci.Kod mostne konstrukcije moraju se odstraniti tvrda zubna tkiva susjednih zuba, a dijasteme su kontraindikacija za njihovu primjenu. Usadci omogućuju izradbu samostalnih žvačnih jedinica, ali je preduvjet dovoljno kosti za primarnu stabilizaciju i dugotrajnost usadka. Kada postoji manjak kosti, koristimo se vođenom koštanom regeneracijom (VKR). VKR dokazana je metoda koštane regeneracije, a uporaba kolagenih membrana znatno povećava učinkovitost opisanoga postupka. Dvadesetsedmogodišnjoj pacijentici operacijom je izvađen prvi gornji sjekutić zbog upalnoga procesa i resorptivnih promjena na kosti kao posljedice uzdužne frakture korijena. Neposredno nakon ekstrakcije kohleacijom je odstranjeno granulacijsko tkivo, koštani defekt ispunjen je Bio-Oss spongioznim granulama, a operacijsko polje pokriveno je Bio-Gide resorptivnom membranom. Godinu dana nakon operacije nastala je koštana regeneracija i ugrađen je ITI Straumannov implantat duljine 12 mm i promjera 3,3 mm. Zbog djelomične bukalne dehiscencije upotrijebljen je Fiziograft. Nakon 6 mjeseci izrađen je fiksnoprotetski nadomjestak.Loss of anterior teeth can be caused by pathological processes, tooth retention (mostly upper canine), result of trauma (avulsion or root fracture) or missing tooth germ. Such defects can be solved by orthodontic treatment (orthodontic space closure), prosthetic treatment (different bridge constructions) or with surgery treatment (dental implants). Inadequancy of orthodontic therapy is long lasting rehabilitation ond mostly esthetical imperfection. At the bridge constructions, hard tissues of adjacent teeth must be removed. Another contraindication is the presence of diastemas. Dental implants enable making selfsupporting mastication units, but require sufficient bone to adequately stabilise. When there are changes in alveolar bone height and width, we use guided bone regeneration (GBR). GBR has proved to be a suitable technique for promoting bone regeneration. GBR treatment with collagen membranes may significantly enhance bone regeneration. The left first incisor of a 27 years old patient was extracted because of resorptive processes on alveolar bone as a result of longitudinal fracture of the root. Immediately after extraction, the bone defect was filled with Bio-Oss spongiosa granules and covered with Bio-Gide resorbable bilayer mambrane. After one year the defect was restored to nearly original condition and ITI Straumann implant was placed. Because of labial dehiscence Fisiograft was used. The definitive restoration was placed after 6 months

ZrO2 Ceramic as an Esthetic Post

Uspješna endodontska terapija omogućuje da se spase jako oštećeni zubi. Manjak retencijske površine zuba najčešće se nadograđuje metalnim, konfekcijskim ili individualnim nadogradnjama. Problem je te restauracije sivoplava obojenost zubnih struktura. Zato nemetalni kolčići i nadogradnje imaju prednost kao retencijska podloga potpuno keramičkim krunicama, osobito kada se radi o prednjim prelomljenim ili obojenim devitaliziranim zubima. Osim staklo keramike sve češću uporabu kao biomaterijal u stomatološkoj protetici ima cirkonij-keramika zbog dobrih estetskih, kemijskih i mehaničkih svojstava te zbog dimenzijske stabilnosti. U radu će biti prikazan slučaj protetske sanacije prednjeg zbog traume prelomljenog zuba. Zub je endodontski obrađen. Temeljem rtg snimke normiranim je čeličnim i dijamantnim svrdlima odstranjena i izbrušena gutaperka do željene duljine korijenskoga kanala. Odabran je kolčić cirkonijevoga oksida (Biopost, Alfred Bech GmbH, Offenburg, Njemačka) prikladne duljine. Kolčić je nahrapavljen i pjeskaren sa zrncima Al2O3, veličine 150µm te adhezivno cementiran. Preostali dio kliničke krune nadomješten je kompozitom. U gingivni sulkus stavljen je retrakcijski končić. Temeljem dvofaznoga otiska izrađena je potpuna keramička krunica (Empress 2, Ivoclar, Schaan). Krunica je konačno pričvršćena adehzivnim cementom. Provedenom terapijom postignut je optimalan estetski i funkcijski učinak. Sve faze slikovno su prikazane.Successful endodontic therapy allows patients to retain severely damaged teeth. A minor retention surface is usually restored with metallic, commercial or individual posts. Silver-gray color posts is an esthetic problem in reconstruction of antetior teeth. Nonmetallic posts in combination with all-ceramic crowns are esthetically preferable for the restoration of endodontically treated anterior teeth with fractured or discolored coronal aspects. Glass ceramics as well as zirconimum oxide ceramik have been used as biomaterials in prosthodontics. Zirconium has good esthetic, chemical and mechanic properties and is dimensionally stable. In this study, a clinical case with prosthetic restoration of an upper fractured incisor has been discribed. After endodontic and radiograph treatment , the root canal was prepared with specific cylindrical steel and diamond burns. Gutta-percha was removed to the optimal depth of the root canal. Zirconium oxide post (Biopost, Alfred Becht GmbH, Offenburg, Germany) was chosen of suitable lenght. After roughening and sandblasting the surface of the ZrO2 post with particles Al2O3, size 150 µm, the post was adhesively cemented. The clinical crown was built with composite. Retraction thread was placed in gingival slucus. Monophase impression was taken. An all-ceramic crown, Empress 2 (Ivoclar, Schaan, Lichtenstein) was made. The ceramic crown was fixed with adhesive cement. Good esthetic and functional effect was achieved. All phases of the therapy have been illustrated by figures

Orthodontic-Prosthodontic Rehabilitation: a Case Report

A 25 year-old female came to the Department of Prosthodontics, complaining of problems with masticatory function, described as pain in both temporomandibular joints during mastication and dissatified with esthetics in the upper jaw. After a thorough clinical escaminations, diagnostic casts and X-ray analysis it was determined that the patent had oligodontium of 10 teeth (14, 15, 17, 18, 24, 25, 28, 38, 44, 48), discoloration of incisors caused by hypomaturated enamel (amelogenesis imperfecta), disproportion of the front teeth (in completely defined microdontia), Angle class II/1 (deep overbite) and compression of the front teeth. The case history showed that the problems were of a congenital nature apart from the frontal compression, caused by inadequate orthodontic therapy at a younger age. Despite numerous congenital abnormalities, the patient had no systemic disorders. In consultation with an orthodontist, the patient commenced orthodontic therapy with a fixed orthodontic appliance in the upper jaw for placing the teeth in the right position for fabrication of a semicircular bridge. After 6 months of orthodontic therapy, a fixed prosthodontic appliance 600321 123006 (upper jaw) was made of metal ceramic. The aim of the therapy was to replace missing teeth, protect existing teeth with hypomaturated enamel and readjust occlusal height. With the new intermaxillary relations and teeth contour esthetic and functional concordance was achieved. After therapy the patient had no pain in the temporomandibular joints

Estimation of Wear Resistance in Acid Solution of Dental Ceramics by Neural Network

It is known that exposure to acid causes damage to the glass surface. The aim of this study was to examine wear resistance, measuring the mass change of dental ceramics after contact with 10-3 mol dm-3 HCl at temperature of 50°C. Four samples of dental ceramics were analyzed: feldspatic ceramic, hydrothermal ceramic, glass ceramic for staining and glass ceramic for layering. The mass concentrations of eluted Na+, K+ and Ca2+ were determined by ion chromatography (IC) and mass concentrations of Si4+ and Al3+ by UV/VIS spectrometry. Measurements were conducted after 1, 2, 3, 6 and 12 months of emersion. For the subject issue, using experimental data, the feedforward backpropagation neural network for estimation of wear resistance of dental ceramics was modelled. The results of 1, 2 and 12 months of emersion were used for the training 13-20-5 model of neural network. Comparison of experimental data and data obtained by estimation (results of 3 and 6 month intervals) of neural network shows that the applied network model provided a very good prediction of wear behavior of dental ceramics with high correlation coefficient (R) and low sum of squared error (SSE) between measurement and estimated output values

Chemical Durability of Dental Ceramic Material in Acid Medium

Stomatološki materijali moraju se ispitati prema strogim kriterijima kako bi se odredila njihova dugotrajna terapijska vrijednost. Kemijska degradacija dentalne keramike povećava njezinu hrapavost i istodobno trošenje antagonističkog zuba ili restorativnog materijala, povećava prianjanje plaka na keramiku, oslabljuje strukturu keramike uzrokujući kritičnu izmjenu iona na njezinoj površini i povećava osjetljivost keramike na buduće kemijske agense. Svrha rada bila je ispitati gubitak mase uzoraka četiriju različitih dentalnih keramika u kiselom mediju. Najmanji gubitak mase izmjeren je kod apatitne staklo-keramike (IPS-Empress 2 za slojevanje) (4,9±0,3 μg/cm2), a najveći kod glinične keramike (Vitadur alpha) (15,0±0,2 μg/cm2). Litijska disilikatna staklo-keramika (IPS-Empress 2 za bojenje) i glinična (IPSClassic) pokazale su vrlo slične rezultate (9,4±3,4 μg/cm2 i 10,1±0,3 μg/cm2). Vrijednosti gubitka mase uzoraka u ovom radu, kao i u većini pronađenih u literaturi, minimalne su, te vjerojatno nemaju kliničke i toksikološke posljedice. Ali, to ne znači da se mogu uopćavati i prenositi na neispitane vrste dentalne keramike.Dental materials need to be thoroughly examined in order to assess their long-term therapeutical value. Chemical degradation of dental ceramic material enhances its roughness, leading to the wear of the opposing natural tooth or restorative material, greater plaque attachment to ceramics, weakening of the ceramic structure causing the critical ion exchange at the surface and enhancing the sensitivity to future chemical agents. The aim of this study was to test loss of mass in samples of four different dental ceramic materials in an acid medium. The least mass loss was recorded in apatite glass ceramic (IPS-Empress 2 for layering) (4.9±0.3 μg/cm2), and most mass loss was recorded in alumina ceramic (Vitadur alpha) (15±0.2 μg/cm2). Lithium disilicate glass ceramic (IPS-Empress 2 for coloring) and alumina (IPS-Classic) showed very similar results (9.4±3.4 μg/cm2 and 10.1±0.3 μg/cm2). The values of mass loss in samples in this work, as well as in the most of the literature, are minimal and presumably do not have any clinical or toxicological effects. However, it does not imply that these values can be generalized and transferred to dental ceramic materials that were not yet analyzed

Dimensional Stability of Elastomeric Impression Materials Disinfected in a Solution of 0.5% Chlorhexidine Gluconate and Alcohol

Dezinfekcija elastomernih materijala za otiske može prouzročiti njihove dimenzijske promjene. Na našoj se klinici kao dezinficijens najčešće upotrebljava 0,5% klorheksidin glukonat. Svrha rada bila je izmjeriti i usporediti linearne dimenzijske promjene koje nastaju u trima elastomerima nakon uranjanja u spomenuti dezinficijens. Radni kalup napravljen je prema ADA specifikaciji br.19. Testirani su Panasil (adicijski silikon), Blend-a-scon (kondenzacijski silikon) i Impregum (polieter). Uzorci su izloženi dezinficijensu, vodi i zraku u četiri razdoblja (10 min., 30 min., 60 min. i tijekom 24 sata). Linearne dimenzijske promjene izmjerene su bezkontaktnim digitalnim alatnim mikroskopom. Rezultati su pokazali najmanje dimenzijske promjene adicijskog silikona s tendencijom širenja. Kondenzacijski silikon skvrčio se unutar tolerantnoga raspona od 0,2 - 0,4%, prema DIN 13913, a polieter je znatno nabubrio. Može se zaključiti da testirani polieter nije prikladno dezinficirati uranjanjem u klorheksidin glukonat, a druga dva materijala pokazuju klinički prihvatljive linearne dimenzijske promjene unutar 24-satne imerzije.Disinfection of elastomeric impression materials used in prosthetic dentistry can cause dimensional changes in the impression materials. 0.5% chlorhexidine gluconate is usually used for disinfection of impressions at the School of Dental Medicine in Zagreb. The purpose of this study was to measure and compare linear dimensional changes of three elastomeric impression materials after their immersion in a certain disinfectant. The master dies were made according to the ADA specification no 19. The tested materials were Panasil (addition silicone), Blend-a-scon (condensation silicone) and Impregum F (polyether). Twelve samples were immersed in disinfectant, twelve in water and twelve left in the air for four different periods of time (10 min., 30 min., 60 min and 24 hours). Linear dimensional changes were measured by a non-contact digital tool microscope. The smallest changes were noticed in addition silicone with the least tendency to expansion. The condensation silicone contracted within a tolerant range of 0.2 - 0.4%, according to DIN 13913. Polyether expanded in the disinfectant significantly. Our results show that the tested polyether is not appropriate for disinfection by immersion in chlorhexidine gluconate, while the other two materials underwent 24-hour immersion with linear dimensional changes within a clinically acceptable range

Orthodontic-Prosthodontic Rehabilitation: a Case Report

A 25 year-old female came to the Department of Prosthodontics, complaining of problems with masticatory function, described as pain in both temporomandibular joints during mastication and dissatified with esthetics in the upper jaw. After a thorough clinical escaminations, diagnostic casts and X-ray analysis it was determined that the patent had oligodontium of 10 teeth (14, 15, 17, 18, 24, 25, 28, 38, 44, 48), discoloration of incisors caused by hypomaturated enamel (amelogenesis imperfecta), disproportion of the front teeth (in completely defined microdontia), Angle class II/1 (deep overbite) and compression of the front teeth. The case history showed that the problems were of a congenital nature apart from the frontal compression, caused by inadequate orthodontic therapy at a younger age. Despite numerous congenital abnormalities, the patient had no systemic disorders. In consultation with an orthodontist, the patient commenced orthodontic therapy with a fixed orthodontic appliance in the upper jaw for placing the teeth in the right position for fabrication of a semicircular bridge. After 6 months of orthodontic therapy, a fixed prosthodontic appliance 600321 123006 (upper jaw) was made of metal ceramic. The aim of the therapy was to replace missing teeth, protect existing teeth with hypomaturated enamel and readjust occlusal height. With the new intermaxillary relations and teeth contour esthetic and functional concordance was achieved. After therapy the patient had no pain in the temporomandibular joints