Abstract Objective The purpose of this study was to investigate and analyze the indentation size effect (ISE) in Vickers hardness of monolithic yttria partially stabilized zirconia (Y-TZP) dental ...ceramics without and with the addition of dental dye A3. The ISE is analyzed using the Mayer law, a proportional specimen resistance (PSR) model and a modified proportional specimen resistance (MPSR) model. Methods Two samples of Y-TZP dental ceramics, trade names BruxZir (provided by Glidewell Laboratories, CA, USA), were investigated. The first sample was polished Y-TZP and the second sample was polished Y-TZP with the addition of dental dye A3, by VITA Classical Shade Guide. The Vickers hardness was measured under the following loads: 0.49 N, 0.98 N, 1.96 N, 4.90, 9.81 N and 29.42 N. Thirty indentations were made on each sample, under each load. Relationships between the applied load, F , and the resulting indentation size, d , have been analyzed by the Mayer law, the PSR model and the MPSR model. Results The Meyer index ( n ) for both Y-TZP dental ceramics is less than 2, which indicates that hardness is dependent on test loads. The PSR model and the MPSR model were used to calculate “true” Vickers hardness or load-independent hardness. Significance All applied mathematical models are suitable for the data analysis, which is confirmed with high correlation coefficients, but the best correlation between measured values and mathematical models was achieved with the MPSR model with a correlation coefficient of 0.9999.
of the study was to analyse translucency parameter (TP values) of glass-ceramics fabricated by different techniques and investigate the effect of the corrosive medium on TP values.
Three specimens of ...each type of IPS e.max ceramics (Ivoclar Vivadent, Schaan, Liechtenstein) were made in three colours (A2, C2 and B3) by three fabrication techniques (layering - e.max Ceram Dentin; heat-pressing - e.max Press; CAD/CAM - e.max CAD). Specimens were made in the form of plates (10 mm x 12 mm x 0.8 mm). CIE L*a*b* values were measured by a spectrophotometer (X-Rite DTP 20 Pulse, Neu Isenburg, Germany) before and after exposure to 4% acetic acid at 80 °C for 16 hours (ISO 6872) to calculate translucency parameter (TP values). Statistical data were analysed using the IBM SPSS 22 software.
IPS e.max Ceram Dentin had significantly the lowest TP values, and IPS e.max Press the highest TP values of all colours (A2, C2, B3), both prior and after exposure to acid (p<0.001). The difference in TP values among colours was evident in the IPS e.max Ceram Dentin material, both before and after exposure to acid with a great effect size (p<0.001; η2 = 0.702 and 0.741), and in the IPS e.max Press material (p<0.001, effect size 0.547 and 0.576). CAD/CAD specimens showed uniform TP values between three colours. Further, exposure to a corrosive medium did not result in a statistically significant change of TP values in any of the materials tested.
Different types of glass-ceramics showed significant difference in TP values both with respect to the fabrication technique and colour. Exposure to a corrosive medium did not result in a statistically significant change of TP values.
Svrha: Analizirati parametar translucencije (TP vrijednosti) staklokeramika izrađenih različitim tehnološkim postupcima te ispitati kako na TP vrijednosti utječu korozivna sredstva. Materijali i ...metode: Izrađena su po tri uzorka IPS e.max keramike (Ivoclar Vivadent, Schaan, Lihtenštajn) u trima bojama (A2, C2 i B3) s trima različitim tehnologijama izrade (slojevanje – e.max Ceram Dentin; toplo-tlačna tehnika – e.max Press; strojno – e.max CAD). Uzorci su bili u obliku pločica dimenzija 10 mm x 12 mm x 0,8 mm. Spektrofotometrom (X-Rite DTP 20 Pulse, Neu Isenburg, Njemačka) izmjerene su CIE L*a*b* vrijednosti za izračun parametra tanslucencije (TP vrijednost) prije i poslije izlaganja 4-postotnoj octenoj kiselini na 80 °C tijekom 16 sati (ISO 6872). Statistički podatci obrađeni su programom IBM SPSS 22. Rezultati: Značajno najmanje TP vrijednosti imao je IPS e.max Ceram Dentin, a najveće IPS e.max Press u svim bojama, prije i poslije izlaganja kiselini (p<0,001). Razlika u TP vrijednostima između boja bila je vidljiva unutar materijala IPS e.max Ceram Dentin prije i poslije izlaganja kiselini, uz veliku snagu efekta (p<0,001; η2 = 0,702 i 0,741) te pri primjeni materijala IPS e.max Press (p<0,001, snaga efekta 0,547 i 0,576). Strojno izrađeni uzorci pokazali su ujednačene TP vrijednosti. Izlaganje korozivnom sredstvu nije rezultiralo statistički značajnim promjenama TP vrijednosti ni za jedan materijal. Zaključak: Različite staklokeramike pokazale su značajne razlike u TP vrijednostima i prema tehnološkom postupku izrade i prema različitim bojama. Izlaganje korozivnom sredstvu nije rezultiralo statistički značajnim promjenama TP vrijednosti.
The aim of this study was to assess and observe the oral hygiene and gingival condition in patients before and after fixed prosthodontic therapy through a 12-month period in combination with oral ...hygiene instructions. It was also analysed how factors, such as type of fixed prosthodontic appliance, constructive material, the position of a fixed partial denture (FPD) in the mouth, age and gender influenced oral hygiene. The dental arches were divided into three segments each and teeth and gingiva were examined using the Plaque and Gingiva Index by Silness and Löe, and for the mineralized deposits assessment the Calculus Index by Green and Vermillion was employed. The preliminary examination was conducted before the prosthodontic therapy, and the reexaminations were carried out 14 days, 1, 6 and 12 months after crown and/or FPD placement. A total of 93 subjects from the original study group of 146 patients attended all clinical examinations, while the rest was excluded. The sample consisted of 60 women, 33 men at age between 21 and 95 (average 51.8). A total of 39 patients had single crowns (C), 50 FPDs and 5 C+FPD. The frequency of plaque found during the preliminary visit was higher than that found in the other periods (p < 0.001). Patients with C showed better oral hygiene levels than patients with FPDs or C+FPDs (p = 0.001). Our results revealed no significant difference in oral hygiene status among patients with FPDs made of different materials (p = 0.083). The worst hygiene levels were found in patients with fixed prosthodontic appliances in both jaws (p = 0.012). Younger patients showed better hygiene levels than the older ones (p = 0.002). Our research showed that appropriate educational and motivational measures can lead to improved oral hygiene, even after FPD placement. Presumably, the oral health in a group of adult patients can be kept acceptable by providing a prophylactic oral hygiene program.
Temporomandibular disorders (TMD) is a joint term that encompasses a number of clinical symptoms that involve the teeth, masticatory musculature and temporomandibular joints (TMJ). They are a ...frequent cause of orofacial medical conditions. The aetiology of disorders is complex and individual etiologic factors are not sufficiently defined. Bruxism, in its centric or eccentric form, is becoming a frequent problem for dentists. The purpose of this study is to show factors of the condyle leading in patients with bruxism by optoelectronic pantography, and to establish the possibility of using optoelectronic pantography in the diagnostic procedure of TMD. Patients were selected (N = 42), with incomplete sets of teeth, without prosthodontic appliances and with traces and symptoms of TMD. After completing the history questionnaire a clinical check up and plaster cast analysis patients with bruxism were selected (N = 22) and without bruxism (N = 20). During the study optoelectronic String-condylocomp LR3, Dentron, D-Höchberg (software JAWS 30) was used. This study showed the possibility of applying optoelectronic pantography in TMD diagnostics and compares history, clinical and condylographic parameters in TMD patients with and without bruxism. Optoelectronic pantography enables us, by using relatively easy methods, to determine a more accurate diagnosis, highly important when choosing therapeutic methods and control of the aforementioned disorders.
Aim To investigate the influence of different cast surface finishingprocess on metal-ceramics bond strength.Methods Six Co-Cr alloy sample groups were cast (Wirobond C,BEGO, Bremen, Germany) and ...randomly selected for use in oneof the six different final processing of the casting surface (oxidation,sandblasting with 110 and 250 µm Al2O3, bonding agent,hydrochloric acid solution) prior to application of feldspathic ceramic(Duceram Kiss, DeguDent, Hanau-Wolfgang, Germany).The testing was carried out with a tensile testing machine (LRXwith Nexygen software, Lloyd Instr., Fareham, UK) (ISO 9693).Results The highest force (66.902 N) for the separation of ceramicsmeasured with the sample sandblasted with 250µm Al2O3,oxidised and repeatedly sandblasted with 250 µm, and the lowestforce (36.260 N) with the sample treated with hydrochloric acidsolution. With all sample groups except the group with the bondingagent (cohesive fracture), an adhesive fracture of the mediumand an adhesive-cohesive fracture of the peripheral part of thefracture surface were observed. The oxidation, prolonged oxidationand the bonding agent do not influence the bond strength ofthe tested metal-ceramic system.Conclusion Different casting surface treatments have an importantrole on the bond strength of the ceramic-metal interface.
Provider: - Institution: University of Zagreb. School of Dental Medicine. - Data provided by Europeana Collections- Zbog specifičnih svojstva cirkonij-oksidna (Y-TZP) zubna keramika ima široku ...primjenu u stomatologiji. Stoga je važno ispitati njenu kemijsku postojanost. Sva ispitivanja su provedena na tri skupine uzoraka Y-TZP zubne keramike BruxZir (Glidewell Laboratoriji 2012): čisti i polirani Y-TZP (uzorak C), polirani Y-TZP s dodatkom A3 boje(uzorak A3) i YTZP glazirani s dodatkom A3 boje (uzorak A3G). U svrhu karakterizacije određen im je kemijski sastav (PIXE analizom), fazni sastav (XRD analizom) i mikrostruktura (SEM analizom). Kemijska postojanost uzoraka praćena je: mjerenjem količine eluiranih iona (AAS i ICP MS metodom), mjerenjem parametara hrapavosti na mikro skali (profilometrom) i nano skali (AFM-om), mjerenjem tvrdoće po Vickersu (u rasponu od HV0,05 do HV3). Prema standardu ISO 6872 ispitivanje kemijske postojanosti zubne keramike provodi se u 4 %-tnoj vodenoj otopini octene kiseline pri 80 C tijekom 16 sati. U ovom radu produženo je vrijeme izloženosti uzoraka do 768 sati (32 dana) u svrhu određivanja brzine korozije. Najveća brzina korozije i promjena parametara hrapavosti na mikro skali određena je za uzorak A3G što se može pripisati kongruentnom otapanju glazure. Izmjerene promjene parametara hrapavosti (na nano skali) i daleko manje brzine korozije uzoraka C i A3 ukazuju na izuzetno dobru kemijsku postojanost cirkonij-oksidne (Y-TZP) zubne keramike u navedenim uvjetima. Vrijednosti tvrdoće (HV3) uzoraka C i A3 prije i poslije korozije nisu se značajno promijenile.XRD analizom je utvrđeno da tijekom procesa korozije dolazi do djelomične fazne transformacije ZrO2iz tetragonske u monoklinsku.- Objectives: Among dental applications, the zirconia based ceramics are widespread becauseof their general properties. Therefore the aim of this study was to determine chemical stability of Y-TZP dental ceramics by modified standard method ISO 6872. Materials andmethods:Three different sample groups of Y-TZP material BruxZir (Glidewell Laboratories 2012.) wereused: sample (C) - pure polished zirconia, sample A3 - polished zirconia with addition of A3 dye and sample A3G - zirconia with A3 dyeand a glazed. Chemical compositon of Y-TZP was determined by PIXE method, phase composition was determined by XRD, microstructure was analysed by SEM. Chemical stability of investigated samples was monitoring by: measuring eluted ions (using AAS and ICP MS methods), measuring surface roughness parameters on microscale (using Perthometer) and nano scale (using AFM), determination Vickers hardness (in range from HV0.05 to HV3). According to the standard ISO 6872 chemical stability of dental ceramics is carried out in4 wt% CH3COOH aqueous solution at 80 C during16 h. In this work exposure time was extended up to 768 hours (32 days) inorder to determine the corrosion rate. Results: Maximum corrosion rate and changing of the roughness parameters on the microscale is determined for sample A3G which can be attributed to the congruent dissolution of glaze. The measured changes of the roughness parameters (at the nanoscale) and much less corrosion rate of samples C and A3 indicate extremely good chemical resistance zirconiumoxide (Y-TZP) dental ceramics ininvestigated conditions. Hardness values (HV3) for samples C and A3 before and after corrosion were not significantly changed. XRD analysis showed that the corrosion processcourse partial tetragonal to monoclinic phase transformation of ZrO2. The roughness parameters, for sample A3G, was significantly increased, showing higher penetration depthin all surface areas after immersion in corrosive media. All three sample groups showed the decreases of hardness by increasing of applied load. Conclusions: The measured changes of roughness parameters (at the nanoscale) and much less corrosion rate for samples C and A3 indicate their extremely good chemical resistance of zirconiumoxide (Y-TZP) dental ceramics in investigated conditions.- All metadata published by Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
Introduction: Among dental applications, the zirconia based ceramics are widespread because of their general properties. The changes in superficial surface roughness correspond to the structural ...changes in the material caused by the influence of corrosion. The aim of this study was to determine chemical stability of glazed Y-TZP using surface roughness measurements. Materials and methods: Five samples of Y-TZP material BruxZir (Glidewell Laboratories S 2012.) with the addition of pigment A3 were sintered, polished and glazed to imitate the finishing process in producing monolithic crowns. After determining the mass of the sample, each sample was immersed in 10 ml of 4 wt. % CH.sub.3COOH aqueous solution. The roughness was measured five times before and after immersion. Results: All measured roughness parameters have significantly increased, showing higher penetration depth in all surface areas after immersion in 4 wt. % CH.sub.3 COOH aqueous solution compared to the initial values. Weight loss of investigated dental ceramics samples was 2.45 mg/cm.sup.2 ± 0.026. Conclusion: Highly acidic conditions augment surface roughness of Y-TZP glazed dental ceramics. Key words Dental Porcelain; Surface Properties; Corrosion Uvod: Cirkonij-oksidna (Y-TZP) keramika zbog specificnih svojstava cesto se primjenjuje u stomatologiji. Gradivni materijal moze korodirati ako na njegovoj povrsini postoji razlika u koncentraciji elektrolita. Nekvalitetna obrada povrsine nadomjeska pridonosi korozivnim procesima koji i sami dodatno narusavaju povrsinsku morfologiju. Svrha ovog istrazivanja bila je ustanoviti kemijsku stabilnost glaziranog Y-TZP-a mjerenjem parametara hrapavosti povrsine. Materijali i metode: Pripremljeno je pet uzoraka keramike Y-TZP (BruxZir, Glidewell Laboratories S 2012) s dodatkom pigmenta A 3. Svi su bili sinterirani, polirani i glazirani--tako su simulirani zavrsni postupci u izradi monolitickih nadomjestaka. Nakon odrecivanja mase uzorka svaki je uronjen u 10 mL 4-postotne otopine octene kiseline. Svi parametri hrapavosti izmjereni su pet puta i to prije izlaganja korozivnom mediju i poslije toga postupka. Rezultati: Znacajan porast izmjerenih parametara hrapavosti, u odnosu na pocetne vrijednosti, upucuje na prodiranje 4-postotne vodene otopine octene kiseline. Zabiljezen je i gubitak tezine uzoraka i to u iznosu od 2,45 mg/cm.sup.2 ± 0,026. Zakljucak: Vrlo kiseli uvjeti povecavaju povrsinsku hrapavost glazirane zubne keramike Y-TZP. Kljucne rijeci keramika; svojstva povrsina; korozija
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