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1.
Int J Esthet Dent ; 15(4): 374-389, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33089255

RESUMO

This article describes a novel concept for treatment planning and execution in the digital era. The aim of the presented workflow was to design, plan, communicate, perform, fabricate, deliver, and maintain a smile makeover restoration entirely through digital technology. The interdisciplinary treatment plan is described from the planning through the diagnostic mock-up to the final restoration. In digital designing, the dental morphology and tooth shape seen by the clinician and technician are interpreted by the computer as a 3D geometric mathematic model. Controlling the geometry provides freedom for the clinician to develop a restorative digital plan that can be followed throughout the patient's treatment. Moreover, new ceramic materials used with computer-assisted techniques have considerably broadened the choices for dental teams and have enhanced the results that can be achieved.


Assuntos
Dente , Fluxo de Trabalho , Cerâmica , Desenho Assistido por Computador , Humanos , Sorriso
2.
Stomatologiia (Mosk) ; 99(5): 111-115, 2020.
Artigo em Russo | MEDLINE | ID: mdl-33034187

RESUMO

Translucent zirconia ceramics for fabrication monolithic restorations is a ceramic material of latest generation. The objective of this literature review is discussing the ways to increase the transparency of zirconia, novel technologies of its manufacturing (part 1) and laboratory procedures for fabrication translucent zirconia restorations, factors affecting the transparency, optical and physico-mechanical properties of the material, as well as indications for its use (part 2).


Assuntos
Cerâmica , Zircônio
3.
Shanghai Kou Qiang Yi Xue ; 29(3): 262-266, 2020 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-33043342

RESUMO

PURPOSE: To observe and compare the stress distribution of implant, crown, abutment and surrounding bone tissues in the aesthetic zone after restoration of resin-ceramic composite single crown, and provide theoretical basis for clinical restoration. METHODS: Three-dimensional finite element models of alveolar bone, implant, crown, and the thickness of different adhesives between crown and abutment (0.05 mm and 0.1 mm) were established by using Mimics 17.0 software.Force was applied at the angle of 130° with the long axis of the implant, the loading position was 2 mm from the incisal cingulum, and other force on the incisal margin was loaded in parallel to the long axis of the implant. The size was 100 N. Linear static stress analysis was carried out to compare the Von Mises stress after single crown restoration with different materials. RESULTS: When the thickness of adhesive was 0.05 mm, and resin cement was selected, after restoration of Enamic, Ultimate resin ceramic composite crown, the peak stress of alveolar bone, implant, crown and abutment was more uniform and decreased slightly, but the difference was not significant compared with that of IPS Empress, blocs Mark Ⅱ ceramic crown. When the thickness of adhesive was 0.05 mm, the peak stress was significantly lower than that of 0.1 mm. There was no significant difference in the stress between glass ionomer cement and resin cement.Under the same conditions, restoration with Ultimate crown had smaller stress value of peak Von Mises. CONCLUSIONS: The stress of resin composite ceramics single crown when applied to implantation in aesthetic area is slightly less and more uniform. The proportion of resin in composites and the thickness of adhesive can affect the stress distribution and peak value.


Assuntos
Implantes Dentários , Cerâmica , Coroas , Análise do Estresse Dentário , Estética Dentária , Análise de Elementos Finitos
4.
Shanghai Kou Qiang Yi Xue ; 29(3): 312-315, 2020 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-33043351

RESUMO

PURPOSE: To compare the aesthetic effects of all-ceramic micro-veneer and minimally invasive ultra-thin veneer in repairing deformed anterior teeth. METHODS: One hundred and twenty patients with deformed anterior teeth were selected for aesthetic restoration. According to the patient's personal condition, a suitable repair protocol was selected. Patients in the experimental group (60 cases) were repaired with all-ceramic micro-adhesive surface, while patients in the control group (60 cases) were treated with minimally invasive ultra-thin veneer. The US Public Health Administration's Evaluation Criteria (USPHS) scores were recorded and compared 6 months, 12 months, and 24 months after restoration. Statistical analysis was performed using SPSS 25.0 software package. RESULTS: There was no significant difference in the integrity, color, marginal closeness, translucency and marginal staining of the restorations between the two groups 24 months after operation (P>0.05). The satisfaction rate of the aesthetics of the experimental group was significantly lower than that of the control group (71.60% vs 93.83%, P<0.05). The incidence of complications such as broken, detached and secondary caries during the follow-up period was significantly lower in the experimental group than in the control group (1.23% vs 11.11%, P<0.05). CONCLUSIONS: The results showed that there is no significant difference in the success rate between the two methods. All-ceramic micro-veneer technique has good long-term effect, fewer complications, easy to collapse and stain the lip margin, but it has a small amount of teeth preparation and a low incidence of pulpitis in the later period. Minimally invasive super-thin veneer has high aesthetic value, so it is necessary to choose appropriate aesthetic repair methods according to the patients' needs.


Assuntos
Porcelana Dentária , Facetas Dentárias , Cerâmica , Cor , Estética Dentária , Humanos
5.
Swiss Dent J ; 130(10): 785-790, 2020 10 12.
Artigo em Alemão | MEDLINE | ID: mdl-33044805

RESUMO

Minimally invasive dentistry includes a wide range of treat­ment options for replacing lost tooth substance or constructing new tooth shapes. An additive restoration concept in combina­tion with composite or ceramic restorations ensures that the tooth substance is protected. The dentist's preferences deter­mine the choice of the restoration material. In this case, a direct composite restoration was selected to close a diastema between tooth 11 and 21.


Assuntos
Dente , Cerâmica , Materiais Dentários , Estética , Estética Dentária
6.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 55(10): 716-721, 2020 Oct 09.
Artigo em Chinês | MEDLINE | ID: mdl-33045781

RESUMO

Three-dimensional (3D) printing prostheses or prosthodontic devices have been preliminarily used in the clinics of prosthodontics. These prostheses or devices include diagnostic prostheses, crowns and fixed bridges, removable denture frameworks, implant surgical template, and custom-made implants, etc. There are three major types of technologies for 3D printing according to the forming principles, namely, light curing, sintering or melting, and melting-condensation. The materials used in 3D printing prostheses or devices include polymers, metals, and ceramics, etc. The advantages of 3D printing prostheses include material-saving, customized manufacturing for restorations, and batch production. However, the precision and strength of prostheses or devices, long-term clinical effects, and grade of maturity in customized manufacturing need further investigation and improving. This article focused on the present application, and the future development of 3D printing technologies in prosthodontic treatments. It will provide beneficial references for the future studies, development, and clinical application of 3D printing technologies and restorations in prosthodontic fields.


Assuntos
Implantes Dentários , Prostodontia , Cerâmica , Coroas , Impressão Tridimensional
7.
Annu Int Conf IEEE Eng Med Biol Soc ; 2020: 3399-3402, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-33018733

RESUMO

Parylene-C has been used as a substrate and encapsulation material for many implantable medical devices. However, to ensure the flexibility required in some applications, minimize tissue reaction, and protect parylene from degradation in vivo an additional outmost layer of polydimethylsiloxane (PDMS) is desired. In such a scenario, the adhesion of PDMS to parylene is of critical importance to prevent early failure caused by delamination in the harsh environment of the human body. Towards this goal, we propose a method based on creating chemical covalent bonds using intermediate ceramic layers as adhesion promoters between PDMS and parylene.To evaluate our concept, we prepared three different sets of samples with PDMS on parylene without and with oxygen plasma treatment (the most commonly employed method to increase adhesion), and samples with our proposed ceramic intermediate layers of silicon carbide (SiC) and silicon dioxide (SiO2). The samples were soaked in phosphate-buffered saline (PBS) solution at room temperature and were inspected under an optical microscope. To investigate the adhesion property, cross-cut tape tests and peel tests were performed. The results showed a significant improvement of the adhesion and in-soak long-term performance of our proposed encapsulation stack compared with PDMS on parylene and PDMS on plasma-treated parylene. We aim to use the proposed solution to package bare silicon chips on active implants.


Assuntos
Dióxido de Silício , Xilenos , Cerâmica , Dimetilpolisiloxanos , Humanos , Polímeros
8.
Wiad Lek ; 73(8): 1677-1680, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33055333

RESUMO

OBJECTIVE: The aim of this study was to compare the wear resistance of such restorative materials as composite resin, feldspathic ceramic, leucite glass ceramic with intact enamel and to draw an analogy with some similar researches. PATIENTS AND METHODS: Materials and methods: In this research 20 extracted human teeth (maxillary incisors) without fillings and carious cavities were used as samples. All samples were disinfected and stored in saline in order to prevent dehydration. Teeth roots were cut off for the measure of fixation on an organic glass plate using chemically polymerizable resin. If necessary, the teeth were also cut on their lateral sides in order to give them equal size. The samples were placed in a frame-holder, located on the lever of the machine MI-2, which determines abrasion resistance under slipping. RESULTS: Results: The research has revealed that the average wear resistance of natural teeth was 122,67±4.9 J/mm3 (Tab 1). The archived result overcomes dental composite resin twice more (62.8±1.21 J/mm3), feldspathic ceramic 6.5 times more (16.32±1.2 J/mm3) and leucite ceramic over the half (73.79±3.12 J/mm3). CONCLUSION: Conclusion: Thus, according to this performed research and the analysis of the relative literature sources it can be stated that dental composite resin and leucite ceramics may be proposed as the materials of choice for anterior restoration of teeth. They have shown the good wear resistance and tolerance to antagonizing natural teeth.


Assuntos
Resinas Compostas , Desgaste dos Dentes , Cerâmica , Humanos
9.
J Adhes Dent ; 22(5): 531-538, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33073784

RESUMO

PURPOSE: To evaluate the roughness, surface energy, and the bond strength of lithium disilicate yielded by two different types of nonthermal plasma (NTP), oxygen- or argon-based, compared to the conventional method. MATERIALS AND METHODS: Ninety-three lithium disilicate (IPS e.max Press) samples were divided into 3 groups: HF (hydrofluoric acid group); ONTP (oxygen-based NTP group); ANTP (argon-based NTP group). Surface energy and roughness analyses were performed before and after surface treatment, and bond strength testing was performed before and after 5000 thermocycles. Scanning electron microscopy (SEM) was used to characterize the surface treatments. Data were submitted to ANOVA and Bonferroni's test with statistical significance set at 5%. RESULTS: The ONTP group presented the highest surface energy values, followed by ANTP and HF. In addition, the ONTP group had higher surface roughness. SEM revealed exposed lithium disilicate crystals in the HF group, but a homogeneous film coverage in both NTP groups. Regarding bond strength, ANTP presented statistically significantly higher values than the other groups before thermocycling, and statistically significantly lower values than the other groups after thermocycling. The HF and ONTP groups presented statistically similar values after thermocycling. CONCLUSION: The bond strength of resin cement to lithium disilicate obtained after oxygen-based NTP was comparable with that obtained after conventional hydrofluoric acid treatment.


Assuntos
Colagem Dentária , Cimentos de Resina , Cerâmica , Porcelana Dentária , Propriedades de Superfície
10.
Am J Dent ; 33(5): 239-242, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33017525

RESUMO

PURPOSE: Concurrently with the growing interest in CAD-CAM systems, several new materials of different chemical nature have become available. As an alternative to ceramics, numerous polymer-based materials have recently been proposed for permanent prosthetic restorations. Aim of this study was to test the CAD-CAM polymer-based materials available on the market, comparing mean flexural strength, Weibull characteristic strength and Weibull modulus. METHODS: Seven types of polymer-based blocks were tested: Lava Ultimate, 3M; Brilliant Crios, Coltene; Cerasmart, GC; Block HC, Shofu; Katana Avencia, Noritake; Grandio Blocs, Voco; Tetric CAD, and Ivoclar-Vivadent. Specimens were cut out from blocks, finished, polished, and tested in a three-point bending test apparatus until failure (n=30). Flexural strength, Weibull characteristic strength, and Weibull modulus were calculated. Flexural strength data were statistically analyzed. ANOVA on Ranks was applied, followed by the Dunn's test for post hoc comparisons (P= 0.05). RESULTS: Flexural strength values (MPa) were measured (mean±standard deviation). Different letters in parentheses label statistically significant differences: Grandio Blocs 266±24(a), Brilliant Crios 259±21(ab); Tetric CAD 254±15(ab); Katana Avencia 241±29(bc); Cerasmart 221±24(cd); Lava Ultimate 196±23(de); Block HC 139±10(e). All the tested materials had flexural strengths greater than 100 MPa, thereby satisfying the requirements of ISO standards for polymer-based materials. For all the tested materials the Weibull characteristic strength was greater than 100 MPa. Weibull modulus ranged between 21.20 (Tetric CAD) and 9.09 (Katana Avencia). CLINICAL SIGNIFICANCE: Even though all the CAD-CAM polymer-based materials marketed in blocks tested in the present study satisfy the requirements of ISO standard for polymer-based materials, their flexural resistance differs significantly. The data presented in the study may be helpful to clinicians for selecting the most appropriate materials for each clinical case.


Assuntos
Proantocianidinas , Cerâmica , Esmalte Dentário , Teste de Materiais , Propriedades de Superfície
11.
J Esthet Restor Dent ; 32(7): 726-733, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32886852

RESUMO

OBJECTIVE: To evaluate the microtensile bond strength of four dental computer-aided design/computer-aided manufactured (CAD/CAM) ceramics after application of four different surface treatments. MATERIALS AND METHODS: Four dental CAD/CAM ceramics were tested: feldspathic ceramic (VITABLOCKS-Mark II), polymer-infiltrated ceramic network (VITA ENAMIC), zirconia-reinforced lithium silicate (VITA SUPRINITY), and yttria-stabilized zirconia (VITA YZ T). Four surface treatments were applied: no treatment, 5% hydrofluoric acid-etching, airborne particle abrasion, and tribochemical silica coating. The ceramic blocks were repaired with nanohybrid composite (Tetric N-Collection). Sixteen test groups of 12 specimens were prepared. After thermocycling, microtensile bond testing was performed. The microtensile strengths values were statistically analyzed using two-way analysis of variance and Tukey's post-hoc test. RESULTS: Repaired feldspathic and resin polymer-infiltrated ceramic network ceramics demonstrated superior microtensile bond strengths compared to zirconia-reinforced lithium silicate and yttria-stabilized zirconia. Etched feldspathic and polymer-infiltrated ceramic network ceramics had higher bond strength than the untreated groups. Surface treatments did not affect the bond strength of zirconia-reinforced lithium silicate and yttria-stabilized zirconia with the exception of etching, which reduced the bond strength of yttria-stabilized zirconia. CONCLUSION: Feldspathic ceramic and polymer-infiltrated ceramic network were repaired with dental composite after surface etching with hydrofluoric acid. Repair of zirconia-reinforced lithium silicate and yttria-stabilized zirconia did not demonstrate promising results. CLINICAL SIGNIFICANCE: Repair of feldspathic ceramic and polymer-infiltrated ceramic network restorations may be a cost-effective means to promote the longevity of dental restorations. However, zirconia and zirconia-reinforced lithium disilicate restorations do not offer such an option.


Assuntos
Colagem Dentária , Cerâmica , Desenho Assistido por Computador , Porcelana Dentária , Análise do Estresse Dentário , Teste de Materiais , Cimentos de Resina , Propriedades de Superfície , Zircônio
12.
J Oral Sci ; 62(4): 430-434, 2020 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-32863318

RESUMO

Perception of tooth shades is subjective and not rated exactly the same by different individuals. In terms of dental esthetics, chairside individualization of dental restorations might help to improve patient satisfaction. This investigation aimed to validate the practicability of a chairside approach for staining resin-based composite restorations. Thirteen inexperienced and 13 experienced participants were recruited to first individualize two CAD/CAM resin-based composite crowns in randomized order with light-curing characterization material using two reference crowns as templates. They then evaluated the characterization procedure. The processing times were recorded, and the clinical quality of the individualized crowns was evaluated by two blinded master dental technicians. Of the 52 crowns examined, 90.4% were assessed as suitable for insertion; there was no difference in quality attributable to the different degrees of experience of the operators. The average time required for characterization of the second crown was significantly shorter than for the first crown (30.9/43.0 min), indicating that the procedure can be implemented using a chairside approach. Among the operators, 80.8% said they would use the individualization technique and staining material again. Chairside staining of CAD/CAM resin-based composite restorations with light-curing characterization materials is practicable and can be recommended for both experienced and inexperienced users.


Assuntos
Porcelana Dentária , Planejamento de Prótese Dentária , Cerâmica , Resinas Compostas , Desenho Assistido por Computador , Coroas , Materiais Dentários , Humanos
13.
Int J Oral Maxillofac Implants ; 35(5): 965-973, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32991647

RESUMO

PURPOSE: The aim of this study was to evaluate the clinical, esthetic, and patient-reported outcomes of one-piece zirconia implants placed in incisal areas using digital surgical templates after 1 year of follow-up. MATERIALS AND METHODS: Patients who had lost an anterior tooth received a 3.3-mm-diameter zirconia implant placed by computer-guided surgery. Implant survival and soft tissue conditions were assessed periodically 1 week, 3 months, 6 months, and 1 year after loading. Standardized radiographs were taken at definitive prosthesis insertion and 1 year postloading to evaluate peri-implant bone loss. Additionally, the esthetic outcomes and patient-reported outcomes were also investigated. RESULTS: Twenty zirconia implants were placed in 20 patients with no implants lost, resulting in 100% survival rates. A minor change in the mean marginal bone level (0.14 ± 0.87 mm) was found between definitive prosthetic loading and 12 months later. Peri-implant soft tissue remained stable throughout the observation period. The mean Pink Esthetic Score and White Esthetic Score were 12.05 and 8.60, respectively, while the mean Gingival Papilla Index scores were 1.55 at the mesial papilla and 1.65 at the distal papilla at the 1-year follow-up. The mean visual analog scale scores for patient perception of the overall process, speech, mastication, and esthetics were 93.3 ± 7.8, 95.1 ± 5.3, 93.6 ± 7.6, and 94.5 ± 6.2 mm, respectively. CONCLUSION: For the 1-year results, 3.3-mm-diameter one-piece ceramic implants placed by computer-guided surgery showed favorable clinical performances with no failure when used for single-tooth replacement in anterior regions.


Assuntos
Implantes Dentários para Um Único Dente , Implantes Dentários , Cerâmica , Estética , Estética Dentária , Seguimentos , Humanos , Projetos Piloto
14.
Int J Prosthodont ; 33(5): 503-512, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32956431

RESUMO

PURPOSE: To assess the clinical outcomes of single-retainer resin-bonded fixed dental prostheses (RBFDPs) and the profilometric changes of pontic sites after a mean of 10 years in function. MATERIALS AND METHODS: Ten patients (mean age 32.4 years) who had received an RBFDP replacing a single anterior tooth were recalled after 10 years. Five patients had received a subepithelial connective tissue graft (SCTG) at the pontic site. The clinical assessment comprised the following parameters: probing depth, bleeding on probing, modified plaque control record, gingival recession, measurement of the width of keratinized mucosa, and intraoral photographs and radiographs. The modified criteria of the United States Public Health Services evaluation system were applied. Additionally, patient satisfaction was recorded. Data were analyzed descriptively, and the 10-year RBFDP survival rates were calculated using Kaplan-Meier analysis. RESULTS: The RBFDP survival rate after a mean follow-up of 10.0 years (range 7.4 to 13.3 years) was 100%. Neither technical failures nor biologic complications were observed. All abutment teeth remained vital, and no secondary caries were detected. Between baseline and follow-up examinations, the profilometric changes at the pontic sites were minimal, exhibiting a loss of -0.03 ± 0.10 mm (no SCTG) and 0.00 ± 0.37 mm (SCTG). CONCLUSION: The present study exhibited high survival rates and low complication rates of the restorations, as well as excellent profilometric stability of the pontic sites over 10 years. The use of an RBFDP is a viable long-term treatment option for replacing a single anterior tooth.


Assuntos
Cerâmica , Zircônio , Adulto , Falha de Restauração Dentária , Prótese Parcial Fixa , Humanos , Taxa de Sobrevida
15.
Int J Prosthodont ; 33(5): 536-545, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32956435

RESUMO

PURPOSE: To evaluate the shear bond strength (SBS) and color stability (ΔE) of four ceramic veneers (VITA VM 9; VITA VM 13; VITA VMK 95; and IPS e.max Ceram) following repair with three different self-adhesive composite resins (Fusio Liquid Dentin; Constic; and Vertise Flow) and BISCO Intraoral Repair Kit + Filtek Supreme (BC + FS). MATERIALS AND METHODS: A total of 96 specimens were prepared per ceramic material, and each ceramic group was divided into subgroups according to testing method (32 specimens for color stability analysis and 64 specimens for SBS testing). ΔE and SBS (SBS1 = non-aged, SBS2 = thermally aged) values of the repaired specimens were calculated. One specimen from each of the thermally aged groups was investigated under scanning electron microscopy (SEM). Two-way ANOVA was used to analyze the mean ΔE, SBS1, and SBS2 values. The differences between SBS1 and SBS2 values were analyzed using independent-samples t test. RESULTS: The lowest ΔE values were calculated for Constic (P ≤ .05). The SBS2 values among all groups were lower than the SBS1 values (P ≤ .05). The lowest SBS2 values were observed for Vertise Flow (2.3 ± 1.47 MPa) (P ≤ .05) and were below the acceptable limit of 5 MPa. CONCLUSION: All of the investigated repair materials in combination with the ceramic veneers exhibited ΔE values that were higher than the clinically acceptable limits. Thermal aging negatively affected the SBS values in all groups (P ≤ .05). All tested self-adhesive composite resins, with the exception of Vertise Flow, could be used instead of a repair kit with flowable composite resin, especially in noncooperative patients, for the purpose of repairing chipping fractures for VITA VM 9, VITA VM 13, and VITA VMK 95 (P > .05).


Assuntos
Colagem Dentária , Cimentos Dentários , Resinas Acrílicas , Cerâmica , Cor , Resinas Compostas , Porcelana Dentária , Humanos , Teste de Materiais , Cimentos de Resina , Resistência ao Cisalhamento , Propriedades de Superfície
16.
Hua Xi Kou Qiang Yi Xue Za Zhi ; 38(4): 376-379, 2020 Aug 01.
Artigo em Chinês | MEDLINE | ID: mdl-32865354

RESUMO

OBJECTIVE: This study aimed to compare the effects of water storage treatment and thermal cycling on the shear bond strength (SBS) of three self-adhesive dual-cure resin cements. METHODS: Six cubic zirconia specimens with side length of 2 cm were obtained by cutting and sintering. Three self-adhering dual-cure resin cements (i.e., Clearfil SAC, RelyX U200, and Multilink Speed) were selected. According to their bonding modes, they were divided into three groups: direct bonding group (direct coating with resin cement), adhesive group (applying universal adhesives and then coating with resin cement), and primer group (applying Z-Prime Plus and then coating with resin cement). According to experimental conditions, each group was divided into two subgroups: subgroup a (water storage at 37 ℃ for 24 h) and subgroup b (thermalcycling for 5 000 times). SBS data were analyzed by one-way ANOVA by using SPSS 19.0 software (P<0.05). The fractured zirconia surface was observed under a stereomicroscope. RESULTS: After water storage for 24 h, the SBS of the adhesive group and the primer group of the three resin cements was higher than that of the direct adhesive group (P<0.05), but the difference in SBS between the adhesive group and the primer group was not significant (P>0.05). After thermalcycling, the SBS of the three types of resin cements decreased (P<0.05); the SBS of the adhesive group was higher than that of the direct adhesive group and the primer group (P<0.05). Fracture mode analysis revealed that the type Ⅲ fracture mode evidently increased after the thermalcycling treatment compared with the water storage treatment. CONCLUSIONS: The universal adhesives and the primer can improve the SBS of self-adhesive dual-cure resin cement in water storage at 37 ℃ for 24 h. The universal adhesives had a better bonding durability than the zirconia primer.


Assuntos
Colagem Dentária , Cimentos de Resina , Cerâmica , Cimentos Dentários , Análise do Estresse Dentário , Teste de Materiais , Resistência ao Cisalhamento , Propriedades de Superfície , Zircônio
17.
Acta Odontol Latinoam ; 33(2): 98, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32920611

RESUMO

The aim of the current study was to compare the effect of two lithium disilicate ceramic processing techniques (pressing and CAD/CAM) on the degree of conversion of resin cement when it is photoactivated and the microshear bond strength of resin cement to ceramics. Two ceramic discs were manufactured: one by the Press technique and another by CAD/CAM technique. Five Variolink Veneer resin cement samples were photoactivated through each ceramic disc and subjected to attenuated total reflectance Fourier transform infrared spectroscopy to evaluate their degree of conversion. To evaluate microshear bond strength, 20 ceramic bars were prepared: 10 using the Press technique and 10 using the CAD/CAM technique. The bars were air abraded with 50-µm Al2O3 particles, treated with 10% hydrofluoric acid for 20 s and subjected to RelyX Ceramic Primer application. Adper Scotchbond Multi-Purpose Adhesive was applied to the bars and cured for 10 s. Two 1-mm-height plastic tubes were placed on each bar and filled with Variolink Veneer resin cement. Each cylinder was cured for 20 s. Then the plastic tubes were removed and the microshear bond strength of each cylinder was tested. Data for degree of conversion (%) and microshear bond strength (MPa) were subjected to Student's t-test (α = 0.05). Both degree of conversion of resin cement photoactivated through ceramic and microshear bond strength of resin cement to ceramic were statistically higher in the group in which ceramic was prepared by CAD/CAM technique (44.74% and 22.18 MPa) than in the group in which the ceramic was prepared by the Press technique (25.71% and 19.83 MPa). The lithium disilicate ceramic processing techniques affected the degree of conversion of resin cement when it is photoactivated through the ceramics and the microshear bond strength of resin cement to ceramics.


Assuntos
Cerâmica/química , Colagem Dentária , Porcelana Dentária/química , Cimentos de Resina/química , Humanos , Teste de Materiais , Propriedades de Superfície
18.
J Oral Sci ; 62(4): 353-355, 2020 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-32741852

RESUMO

Computer-aided design/computer-aided manufacturing (CAD/CAM) restorative materials have been widely used owing to a number of advantages, including stable quality of the materials, lower costs, and time-saving factors. Resin-based CAD/CAM materials for definitive restorations are classified into two groups: dispersed nanoparticle-filled composite resin and polymer-infiltrated-ceramic-network materials. Resin-based CAD/CAM materials have been applied to single crown restorations as a monolithic structure for the posterior region. In addition, resin-based CAD/CAM restorations have been applied recently for the anterior area. This literature review summarizes clinical outcomes, such as survival rates and clinical complications of single crown restorations fabricated with resin-based CAD/CAM materials.


Assuntos
Desenho Assistido por Computador , Coroas , Cerâmica , Resinas Compostas , Materiais Dentários , Porcelana Dentária , Planejamento de Prótese Dentária , Teste de Materiais
19.
Indian J Dent Res ; 31(3): 470-474, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32769285

RESUMO

Objectives: To evaluate the leachable components of resin cements in oral simulating fluids using high performance liquid chromatography and its resultant shear bond strength with ceramics. Methods: Forty extracted permanent human mandibular molar teeth were sectioned horizontally with a disc beneath the dentino-enamel junction to expose the coronal dentin surface and later finished with 600-grit silicon carbide paper to create a uniform flat surface. Forty Lithium Di-silicate Ceramic block cylinders were sliced in a saw cutting machine at 250 rpm under water-cooling to obtain the discs. The teeth and the ceramic discs were then randomly assigned to two groups on the basis of material used for luting the ceramic disk. Group I: Ceramic disc luted with tooth surface using Variolink II Dual cure Resin Cement, Group II: Ceramic disc luted with tooth surface using multilink speed self-adhesive self-curing resin cement. All ceramic discs were etched with 5% HF acid (IPS Ceramic Etching Gel, Ivoclar, Schaan, Liechtenstein) for 20 seconds, then rinsed thoroughly for 20 seconds and dried for 20 seconds. Ceramic specimens were luted on dentin surfaces with the application of 5 kg load. The samples were stored in 75% ethanol solution for 2 weeks at 37 degree Celsius for chemical aging. HPLC Analysis were performed to analyze the eluted monomer. After HPLC Analysis, Samples were then loaded using universal testing machine for the evaluation of shear bond strength between ceramic discs and the resin cements before and after the elution of monomers. Results: Under HPLC analysis, results showed that the peak release of monomer is Bis-GMA in both the groups. The shear force required to break the bond between the ceramic luted to tooth surface with the resin cements were more for Group I. Statistical results: The statistical analysis was done using ANOVA and paired t-test and it shows P value ≥0.05, hence the null hypothesis is rejected. Conclusion: The monomer eluded from all the groups are identified as Bis-GMA, The eluded monomer decreases the bond strength between the resin cement and the ceramic due to water sorption, The Variolink II (dual cure) resin cement shows improved bond strength than the Multilink (self-cure self-adhesive) resin cement.


Assuntos
Colagem Dentária , Cimentos de Resina , Cerâmica , Cimentos Dentários , Porcelana Dentária , Análise do Estresse Dentário , Humanos , Teste de Materiais , Resistência ao Cisalhamento , Propriedades de Superfície
20.
Nat Commun ; 11(1): 3840, 2020 07 31.
Artigo em Inglês | MEDLINE | ID: mdl-32737293

RESUMO

Currently, human magnetic resonance (MR) examinations are becoming highly specialized with a pre-defined and often relatively small target in the body. Conventionally, clinical MR equipment is designed to be universal that compromises its efficiency for small targets. Here, we present a concept for targeted clinical magnetic resonance imaging (MRI), which can be directly integrated into the existing clinical MR systems, and demonstrate its feasibility for breast imaging. The concept comprises spatial redistribution and passive focusing of the radiofrequency magnetic flux with the aid of an artificial resonator to maximize the efficiency of a conventional MR system for the area of interest. The approach offers the prospect of a targeted MRI and brings novel opportunities for high quality specialized MR examinations within any existing MR system.


Assuntos
Neoplasias da Mama/diagnóstico por imagem , Cerâmica/efeitos da radiação , Espectroscopia Dielétrica/métodos , Imagem por Ressonância Magnética/métodos , Espectroscopia de Ressonância Magnética/métodos , Adulto , Cerâmica/química , Espectroscopia Dielétrica/instrumentação , Radiação Eletromagnética , Desenho de Equipamento , Feminino , Voluntários Saudáveis , Humanos , Imagem por Ressonância Magnética/instrumentação , Imagens de Fantasmas , Razão Sinal-Ruído
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