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1.
Braz Dent J ; 31(1): 69-77, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32159709

RESUMO

The objective was to evaluate the color stability of ceramic veneers luted with resin cements and pre-heated composite resins (60oC) for 12 months, and determine the degree of conversion (DC) of the luting agents. Two resin cements (AllCem Veneer, light-cured (LRC) and AllCem, dual-cured (DRC)] and three composite resins [Z100 (MNCR-minifilled), Herculite Classic (MHCR-micro-hybrid) and Durafill (MCCR-microfilled)] were used for cementing 0.8-mm-thick lithium-silicate glass-ceramic laminates (Suprinity, shade B2-HT, Vita) on bovine enamel (n=10). The specimens were stored at 37oC in distilled water. CIELab parameters were determined at 24h after luting (baseline), 7, 30, 90, 180 days and 12 months. Three specimens were prepared for DC evaluation, performed by micro-Raman spectroscopy. Data were analyzed by ANOVA and Tukey's test (a=5%). For ΔEab and ΔE00, there were significant differences for luting material (p<0.001), time (p<0.001), and double interaction (p<0.001). The groups cemented with MHCR (1 year), MCCR (90 days and 1 year) and MCCR-PH (1 year) were the ones with ΔE values greater than the acceptability threshold. All other groups maintained their ΔE lower than the acceptability threshold after 1 year in distilled water. Regarding DC, there were no significant differences (p=0.127) among the materials. Non-significant negative correlations were observed between the mean ΔEab and DC (R=-0.65) and ΔE00 and DC (R=-0.64). A significant positive correlation was observed mean ΔEab and ΔE00 (R=0.99). It was concluded that the different luting agents influenced the final color of the restorations. The heating of the composite resins did not affect their DC.


Assuntos
Cerâmica , Cimentos de Resina , Animais , Bovinos , Cor , Resinas Compostas , Porcelana Dentária , Facetas Dentárias , Seguimentos , Teste de Materiais
2.
Int J Oral Maxillofac Implants ; 35(1): 100-106, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31923292

RESUMO

PURPOSE: To test a novel implant metal-acrylic prosthesis design in comparison to a conventional prosthesis design through simulation of cyclic masticatory loading. The novel design involved digital designing and fabrication of the framework and the matched veneering acrylic resin material. MATERIALS AND METHODS: Ten prostheses were fabricated for each group. All the prostheses exhibited a similar external design on two implants with a distal cantilever. The conventional group comprised a milled metal framework with mechanically retained acrylic denture teeth via vertical pins. The digital prosthesis group incorporated an inverted T-shape bar and a monolithic milled acrylic resin veneer. The resin veneer was subsequently adhesively attached on the bar. All prostheses were thermally aged and subjected to laboratory cyclic loading at the cantilever region. The load-to-failure and the number of cycles until failure were collected. Furthermore, failed specimens were analyzed to determine the mode of failure. RESULTS: The digital prostheses failed at significantly greater load-to-failure (1,570.0 N ± 116.0 N) and number of cycles (124,857 ± 21,608) than the conventional prostheses (load-to-failure = 1,015.0 N ± 47.4 N; number of cycles = 28,452 ± 6,559). The conventional prostheses failed by fracturing of the acrylic teeth and veneering material that led to exposure of the metal framework. Half of the digital prostheses failed by superficial chipping of the veneering material, while the other half failed by the deformation and fracture of screws. CONCLUSION: Within the limitations of this study, the digital prostheses with the novel design and monolithic veneering material showed significantly higher strength compared with the conventional prostheses. The mode of acrylic failure of the digital prostheses was more favorable.


Assuntos
Prótese Dentária Fixada por Implante , Facetas Dentárias , Resinas Acrílicas , Falha de Restauração Dentária , Teste de Materiais , Metais
3.
J Prosthodont ; 29(2): 151-160, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31663223

RESUMO

PURPOSE: To evaluate the influence of different preparation designs and depths on the stress field developed in maxillary central incisors restored with veneers made with different ceramic materials using finite element analysis (FEA). MATERIALS AND METHODS: A linear static three-dimensional finite element analysis model was used with the aid of reverse engineering to develop digital models of maxillary central incisors restored with ceramic veneers, according to two different preparation depths (thin vs deep) and two different preparation designs (feather edge vs butt joint). Three ceramic systems were tested: (i) feldspathic porcelain, (ii) heat pressed glass ceramic IPS Empress 2 (Ivoclar Vivadent AG), and (iii) heat pressed glass ceramic IPS e.max-Press (Ivoclar Vivadent AG). Each model was subjected to a compressive force of 200N applied to the palatal surface 2 mm below the incisal edge. The longitudinal axis of the restored tooth formed an angle of 130o with the direction of the force. The biomechanical behavior of the different models was examined according to the von Mises stress criterion. Statistical analysis was performed using nonparametric confidence interval estimation using bootstrapping. RESULTS: The maximum observed stress values were calculated and found to be similar between prepared and intact teeth. The cervical margin of the veneers displayed the highest von Mises stress values. Irrespectively of the depth and preparation design, the biggest von Mises stress values were observed at the veneer structures with the following order: (i) IPS Empress 2, (ii) IPS e.max-Press, (iii) feldspathic (p = 0.001). Preparation depth resulted in statistically significant differences (p = 0.001) in the stress distribution in the majority of tested structures. As the preparation depth was increased, the stresses within the veneer structure and the tooth structures were decreased. No statistically significant differences were detected in the stresses among the different restored models, when the preparation design was considered. CONCLUSIONS: This FEA study suggests that ceramic veneers could restore the biomechanical behavior of prepared central incisors and made it similar of that of an intact tooth. Regardless of the preparation depth and design and the ceramic system used, the cervical margin of ceramic veneers presents the highest von Mises stress values. When feldspathic porcelain was compared with lithium disilicate (IPS e.max Press), the latter displayed the lowest transfer of stresses to dental tissues. An increase in preparation depth resulted in a statistically significant stress decrease in both the veneer and the tooth.


Assuntos
Facetas Dentárias , Incisivo , Cerâmica , Porcelana Dentária , Análise do Estresse Dentário , Análise de Elementos Finitos
4.
Oper Dent ; 45(1): 10-18, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31373889

RESUMO

Pronounced white color alterations due to structural anomalies of the enamel are often insufficiently masked by bleaching techniques or resin infiltration procedures alone. This frequently leads to the choice of more invasive prosthetic restorations in order to correct tooth color and form. This article describes a minimally invasive treatment option for esthetic and functional rehabilitation in the case of a 13-year-old female patient with suspected severe fluorosis and misalignment of the anterior teeth. The restorations were performed using underlying resin infiltration to homogenize the tooth shade. In a second step, direct composite veneers were applied on top to attain a natural tooth color and adjust tooth alignment and form. By joining the two minimally and noninvasive techniques, this treatment option combines the directive for preservation of hard tooth structure while treating adolescents with the benefits of easy adaptation and repair when the occlusion is still in adjustment.


Assuntos
Fluorose Dentária , Clareamento Dental , Adolescente , Cor , Resinas Compostas , Esmalte Dentário , Facetas Dentárias , Estética Dentária , Feminino , Seguimentos , Humanos
5.
J Prosthet Dent ; 123(2): 338.e1-338.e6, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31839330

RESUMO

STATEMENT OF PROBLEM: Delamination failure may occur between ceramic frameworks and veneering ceramics, shortening the lifetime of fixed dental prostheses in load-bearing areas. PURPOSE: The purpose of this in vitro study was to compare the effect of different repeating CO2 laser treatment methods and conventional approaches on the shear bond strength of zirconia frameworks and veneering ceramics. MATERIAL AND METHODS: Zirconia disks (N=110) were prepared and divided into 5 groups: milling without surface treatment (group M), airborne-particle abrasion (group APA), single laser treatment (group LX1), 2 laser treatments (group LX2), and 3 laser treatments (group LX3). The specimens in the first 2 groups were treated before the framework was coated using the spraying technique. Specimens in the remaining groups were coated with veneering ceramic using the spraying process, and then subjected to laser treatment. Surface roughness and topography, interface properties, phase transformation, shear bond strength, and fracture modes were investigated. Outcomes were analyzed using a profilometer, a scanning electron microscope (SEM) equipped with energy dispersive spectroscopy (EDS), X-ray diffractometry (XRD), a stereomicroscope, and a universal testing machine for mechanical testing. RESULTS: The XRD showed that phase transformation from tetragonal to monoclinic occurred after airborne-particle abrasion. This phenomenon was not observed in laser-treated specimens. Groups LX2 and LX3 had the highest surface roughness values, 1.18 ±0.23 µm and 1.21 ±0.22 µm, among all groups, and group LX3 had the highest shear bond strength values for unaged and aged conditions, 32.08 ±2.45 MPa and 31.43 ±2.07 MPa. The mixed-fracture mode was the most common type of fracture observed. CONCLUSIONS: The results indicated that the shear bond strength between the zirconia framework and veneering ceramic was higher after laser surface treatments than after milling alone or after airborne-particle abrasion. Laser treatment methods, particularly LX2 and LX3, could be considered reliable approaches for zirconia surface treatment.


Assuntos
Colagem Dentária , Facetas Dentárias , Cerâmica , Porcelana Dentária , Análise do Estresse Dentário , Teste de Materiais , Resistência ao Cisalhamento , Propriedades de Superfície , Zircônio
6.
J Prosthodont ; 29(1): 56-61, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31054172

RESUMO

PURPOSE: To evaluate the shear bond strength between various CAD/CAM veneer materials and the zirconia ceramic core. MATERIALS AND METHODS: Ninety square prism zirconia specimens (10 specimens per each group, n = 10) in dimensions of 10 × 5 × 5 mm were prepared. Eighty square prism veneering specimens (40 feldspathic ceramic [Cerec Bloc] and 40 lithium disilicate [IPS e.max CAD]) in dimensions of 3 × 3 × 1 mm were connected to zirconia specimens. Conventional layering was applied to the remaining zirconia specimens as control group (n = 10). CAD/CAM-produced veneers were connected to the zirconia specimens using fusion porcelain or resin cement. One of following treatments were applied to the cemented specimens: no surface treatment, HF etching of the veneering material, or HF acid etching of the veneer in combination with the application of a glaze layer to the zirconia surface. Following the veneering procedures, a shear bond strength test was performed at a speed of 1 mm/min using a universal testing machine. Univariate ANOVA (α = 0.05) was performed for statistical analyses of the obtained data. RESULTS: Statistically significant differences were not found among the materials (F = 0.176, p = 0.656), while statistically significant differences were found amongst the veneering procedures (F = 57.921, p < 0.001). Statistical differences were observed between the groups (F = 13.766, p < 0.001). The highest shear bond strength values were observed in IPS e.max CAD specimens connected to zirconia with low fusion porcelain (27.11 ± 7.7 MPa), and the lowest values were observed in IPS e.max CAD specimens connected to zirconia with resin cement without surface treatment (9.82 ± 2.8 MPa). The application of fusion porcelain with IPS e.max CAD (p = 0.967) and Cerec Blocs (p = 1.00) showed statistically similar results to those with conventional layering. CONCLUSIONS: The application of fusion porcelain to bond zirconia and digitally produced veneering material can serve as an alternative veneering method to the conventional layering method by accelerating and facilitating clinical and laboratory stages.


Assuntos
Colagem Dentária , Facetas Dentárias , Cerâmica , Porcelana Dentária , Análise do Estresse Dentário , Teste de Materiais , Resistência ao Cisalhamento , Propriedades de Superfície , Zircônio
7.
J Prosthodont ; 29(1): 26-33, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29968266

RESUMO

PURPOSE: To evaluate the influence of various Y-TZP thicknesses and veneer firing cycles on the strength of two ceramic veneers. MATERIALS AND METHODS: 180 Y-TZP cores of 0.5, 1.0, and 5.0 mm thickness were prepared followed by sintering in a high temperature furnace; 180 presintered veneering ceramic discs (Vita VM9 porcelain and e.max Ceram) were also prepared using a mold. The discs were placed on zirconia plates (zirconia cores) of different thickness (0.5, 1.0, and 5.0 mm) and exposed to different firing cycles (Vita VM9 porcelain-910, 930, and 950°C; e.max Ceram-750, 770, and 790°C). Ball-on-three-balls flexural strength test was performed (universal testing machine) at a crosshead speed of 0.5 mm/min. Scanning electron microscopy of fractured specimens was performed. Means and standard deviations of flexural strength were analyzed using Tukey-Kramer HSD test for multiple comparisons. RESULTS: Specimens within material groups showed no significant difference (p > 0.05) for flexural strength with respect to Y-TZP core thickness (0.5, 1.0, and 5.0 mm) (VM9 [117.30 ± 14.328, 117.75 ± 13.66, 113.75 ± 20.10], e.max Ceram [94.79 ± 17.5, 100.02 ± 14.7, 95.23 ± 15.4]). Flexural strength within material groups with respect to different firing cycles ([VM9-910, 930, 950°C], e.max Ceram [750, 770, 790°C]), for VM9 (111.49 ± 15.7, 120.86 ± 13.2, 116.46 ± 18.4), and e.max Ceram (94.64 ± 15.2, 101.6 ± 16.69, 93.8 ± 15.20) showed no significant difference (p > 0.05). CONCLUSIONS: Different zirconia thicknesses (0.5, 1.0, and 5.0 mm) and veneer firing cycles for Vita VM9 and e.max ceramics failed to show any significant influence on their biaxial flexural strengths.


Assuntos
Porcelana Dentária , Facetas Dentárias , Cerâmica , Análise do Estresse Dentário , Resistência à Flexão , Teste de Materiais , Propriedades de Superfície , Zircônio
8.
J Prosthet Dent ; 122(6): 565.e1-565.e7, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31699449

RESUMO

STATEMENT OF PROBLEM: Color matching between a zirconia-based ceramic restoration and a natural tooth is a common clinical challenge. PURPOSE: The purpose of this in vitro study was to investigate the effects of the number of firings, veneer thickness, and zirconia core translucency on the final color and translucency of zirconia-based ceramic restorations. MATERIAL AND METHODS: Sixty disk-shaped zirconia specimens (10×1 mm) were prepared in high and low translucencies (n=30 per translucency group). Each zirconia group was subdivided into 3 subgroups (n=10) veneered with ceramic layers of 0.5-, 1-, and 1.5-mm thicknesses. The specimens were then subjected to 1, 3, 5, and 7 firing times. Color and translucency parameters were measured by using a spectrophotometer. Data were analyzed by using multifactorial repeated measures ANOVA and subgroup analysis (α=.05). RESULTS: The number of firings affected the L*, a*, and b* values and translucency parameter in both zirconia-based systems with different veneer thicknesses (P<.05). Increasing the veneer thickness decreased the translucency parameter and increased the L*, a*, and b* values in both zirconia-based systems (P<.05). The color difference values (ΔE) were the highest between 1 and 3, 1 and 5, and 1 and 7 firings, and the lowest between 5 and 7 firings in both zirconia systems. CONCLUSIONS: Repeated firings and porcelain veneer thickness affected the final color and translucency of both zirconia systems and, consequently, adversely influenced the esthetic outcomes. Thus, these factors should be considered in the tooth preparation and laboratory phase.


Assuntos
Porcelana Dentária , Facetas Dentárias , Cerâmica , Cor , Estética Dentária , Teste de Materiais , Zircônio
9.
Int J Prosthodont ; 32(6): 471-474, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31664262

RESUMO

PURPOSE: To report on the 10-year clinical treatment outcomes for a strictly applied clinical protocol for pressable lithium disilicate glass-ceramic laminate veneers (LDLVs) placed by two experienced dentists. MATERIALS AND METHODS: A 10-year follow-up assessment of 364 LDLVs placed in 41 patients was undertaken with the clinical criteria color/esthetic match of the porcelain surface, chipping and fracture occurrence, marginal discoloration, and integrity, assessed using the modified United States Public Health Service scoring system. RESULTS: After 10 years, the survival rate was 97.4%. Complications occurred in 1.64% of the restorations (fractures and debonding in 0.55% and 1.09%, respectively). CONCLUSION: A strict, repeatable protocol for placing veneers with experienced dentists yielded good results.


Assuntos
Porcelana Dentária , Facetas Dentárias , Falha de Restauração Dentária , Odontólogos , Estética Dentária , Humanos , Estudos Retrospectivos
10.
Int J Prosthodont ; 32(6): 533-540, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31664271

RESUMO

PURPOSE: To investigate the need for photoactivation of the adhesive system inside ceramic laminates before the luting procedure and to evaluate the color stability, nanohardness, and elastic modulus of the adhesive interface activated with singlewave and polywave light-curing units. MATERIALS AND METHODS: A total of 44 lithium disilicate ceramic veneers (7.0 mm × 8.0 mm × 0.6 mm) were fabricated, bonded to enamel, and sorted into four experimental groups (n = 11 each) according to the type of light-curing unit (Radii-Cal [singlewave] or Valo [polywave]) and mode of adhesive system activation (with or without previous photoactivation). Two luting agents were used: the Tetric N-Bond adhesive system and Variolink Veneer resin cement. A visible ultraviolet spectrophotometer was used to evaluate the color stability before and after UVB artificial accelerated aging for 252, 504, and 756 hours (n = 8 samples from each group). A nanohardness tester under a load of 1,000 µN was used to evaluate the nanohardness and elastic modulus (n = 3 samples from each group). Data regarding the color stability and the mechanical properties (nanohardness and elastic modulus) were subjected to analysis of variance and Tukey protected least significant difference test (α = .05). RESULTS: Prior activation of the adhesive system, the distinct light-curing units, and different aging periods exerted no significant difference on the color stability or mechanical properties of the resin cement (P > .05), except for in the group activated with Radii-Cal after 756 hours, in which the nonprevious activation showed lower color alteration compared to the previous photoactivation (P = .0285). Without prior activation of the adhesive with Valo, the polywave unit promoted higher nanohardness and elastic modulus values in the adhesive system (P < .05). CONCLUSION: In general, singlewave and polywave light-curing units promoted no difference in color stability or the mechanical properties of the adhesive interface. The prior curing of an adhesive system inside ceramic laminate is not necessary.


Assuntos
Cimentos Dentários , Facetas Dentárias , Cerâmica , Cor , Porcelana Dentária , Teste de Materiais , Cimentos de Resina
11.
Dent Mater J ; 38(6): 1043-1052, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31582596

RESUMO

The aim of this study was to investigate the effect of microslits formed by Nd:YVO4 laser beam machining on the bond strength between two types of zirconia, yttria-partially stabilized zirconia (Y-TZP) and ceria-partially stabilized zirconia/alumina nanocomposite (Ce-TZP/A), and porcelain or two types of resin. Zirconia disks were divided into three groups: 1) non-treated (NT); 2) blasted with alumina particles (AB); 3) microslits fabricated on a zirconia surface by laser beam machining (MS). After veneering porcelain or resins on zirconia specimens, halves of the resin specimens were thermocycled up to 20,000 cycles. The shear bond strength between porcelain and both types of zirconia was not improved by the microslits. Before and after thermocycling, the bond strength between an indirect composite resin or acrylic resin and Y-TZP with microslits was the highest. It was concluded that the microslits on Y-TZP enabled micromechanical interlocking and improved the bond strength and durability of the resins.


Assuntos
Colagem Dentária , Materiais Dentários , Cerâmica , Porcelana Dentária , Facetas Dentárias , Teste de Materiais , Resistência ao Cisalhamento , Propriedades de Superfície , Ítrio , Zircônio
12.
Dent Med Probl ; 56(3): 273-278, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31577071

RESUMO

BACKGROUND: Porcelain sectional veneers with no preparation (no-prep) are an ultra-conservative choice for the esthetic treatment of the anterior teeth. They can be made from a sintered feldspathic porcelain, which gives a great appearance with small thickness, but there are still concerns about the fracture strength of this material. OBJECTIVES: The aim of this study was to evaluate the fracture strength of porcelain sectional veneers made from 2 different sintered feldspathic porcelains. MATERIAL AND METHODS: Twenty recently extracted human incisors were randomly divided into 2 groups according to the porcelain material (n = 10). The 1st group was applied the IPS Style® Ceram feldspathic porcelain and the 2nd group - GC InitialTM MC. The porcelain sectional veneers were fabricated following the manufacturers' instructions. After the veneers bonded with resin cement (Variolink® N), the fracture strength was measured using a universal testing machine (Instron®1195) at 1 mm/min until failure occurred. Failure modes were determined under a stereomicroscope. RESULTS: The mean fracture strength for group IPS Style Ceram was higher than that for group GC Initial MC (182.7 N and 155.7 N, respectively). The lowest value was observed in group IPS Style Ceram (78 N) and the highest value - also in the group IPS Style Ceram (294 N). Student's t-test demonstrated no statistically significant differences between the 2 groups (p > 0.05). CONCLUSIONS: There was no difference in the fracture strength of the porcelain sectional veneers for the 2 types of sintered porcelain used in this study. Cohesive failure within the porcelain sectional veneer was the most common mode of failure.


Assuntos
Porcelana Dentária , Facetas Dentárias , Análise do Estresse Dentário , Estética Dentária , Resistência à Flexão , Humanos , Incisivo , Teste de Materiais
13.
Braz Dent J ; 30(5): 459-466, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31596330

RESUMO

The aim of this study was to evaluate of pre-heating, filler contents and ceramic thickness on film thickness, microshear bond strength, degree of conversion and color change on ceramic veneers. Two experimental composites were prepared (Bis-GMA/UDMA/BisEMA/ TEGDMA), with different amounts of filler (65% or 50%wt) simulating a conventional and a flowable composite. The flowable (F) was used at room temperature and, the conventional either at room temperature (C) or pre-heated (CPH). Disk-shaped ceramics with different thickness (0.4 mm, 0.8 mm, 1.5 mm) were prepared. The film thickness was evaluated according to the ISO 4049 (n=10). The microshear bond strength (n=10) was evaluated in enamel using tubing specimens light-cured through the ceramic veneer. The degree of conversion was evaluated using Raman spectroscopy. The color change of the ceramic restorations (n=10) was evaluated by spectrophotometry. The results were submitted to 2-way ANOVA and Tukey's post hoc test (a=5%). For the film thickness 1-way ANOVA was used (a=5%). The C presented the thicker film thickness; the CPH produced a similar film thickness in comparison to the F. All composites showed similar microshear bond strength. The degree of conversion of the F was higher than the C and CPH. The degree of conversion of the composites photo-activated through a 0.4 mm was higher than the composites photo-activated through thicker ceramics. The C showed the highest color change, while the CPH showed similar color change to the F. In conclusion, pre-heated conventional composites seem to be a potential alternative to lute ceramic veneers such as the flowable composites.


Assuntos
Facetas Dentárias , Cimentos de Resina , Cerâmica , Resinas Compostas , Porcelana Dentária , Calefação , Teste de Materiais
14.
Braz Oral Res ; 33: e0088, 2019 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-31531566

RESUMO

The main of the study was quantify the effect of two ceramics with two underlying resin cements on apparent fluorescence levels. Buccal surfaces of two bovine incisors were ground flat producing one enamel and one dentin substrate. The veneers were fabricated (0.5 and 1.0 mm thickness) using two ceramics (IPSe.max Press and IPSe.max Zirpress, Ivoclar Vivadent). Veneers were cemented using either light-cured (Variolink II, Ivoclar Vivadent) or self-adhesive dual (Rely X U200, 3M ESPE) cement. The layered Control group materials had no cement application. Semi-quantitative fluorescence image analysis (Matlabs software, Matworks) involved processing the images as captured under each daylight (DL, Gretagmacbeth) and ultraviolet illuminants (UVA, Sylvania) within a neutral-gray lightbox (Macbeth Spectral Light). Statistical analysis of the quantitative fluorescence values was performed using two-way ANOVA and Tukey's test (p < 0.05). The e.max Zirpress on the dentin substrate produced greater fluorescence (p < 0.05) when subjected to UV illumination and more fluorescence (p < 0.05) than e.max Press in both cement groups. Light-cured cement produced higher (p < 0.05) fluorescence than the dual-cement with e.max Press on enamel under UV illumination. The fluorescence for e.max Press on the dentin substrate was greater (p < 0.05) than for e.max Zirpress using dual self-adhesive cement subjected to daylight illumination. Thus, it is possible to conclude that the combination of ceramic and cement produce definite, significant effects on the apparent fluorescence, vital quality for restorative dentistry.


Assuntos
Cerâmica/química , Facetas Dentárias , Imagem Óptica/métodos , Cimentos de Resina/química , Animais , Bovinos , Esmalte Dentário/química , Esmalte Dentário/efeitos dos fármacos , Dentina/química , Dentina/efeitos dos fármacos , Luz , Teste de Materiais , Valores de Referência , Reprodutibilidade dos Testes , Propriedades de Superfície
15.
Int J Esthet Dent ; 14(4): 420-432, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31549107

RESUMO

Direct freehand veneers with composite resin (CR) require high clinician ability and a long chair time. Although CR restorations remain the most-used technique for meeting high esthetic demands, and new technologies mean that materials are nowadays more similar to tooth structure, layering techniques for natural results are still considered difficult to achieve. Through advances in adhesive dentistry, systems of prefabricated veneers using conventional techniques have been launched onto the market as an option for the clinician. This case report presents complete step-by-step descriptions of two techniques using prefabricated templates for directly built-up veneers. Both maxillary lateral incisors were simultaneously reconstructed with direct CR veneers with different layering techniques to achieve esthetic results in a shorter chair time. Simple stratification techniques using prefabricated templates may allow clinicians to optimize both time and clinical outcome while obtaining predictable results.


Assuntos
Facetas Dentárias , Estética Dentária , Resinas Compostas , Incisivo
16.
Braz Oral Res ; 33: e009, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31508728

RESUMO

This study investigates the color correspondence of resin cements and try-in pastes, and the color stability of bonded lithium disilicate ceramic disks. Resin composite disks were fabricated (n = 36) to serve as the background for lithium disilicate disks prepared in two thicknesses (0.5 and 1.0 mm, n = 18 each). Two brands were used for try-in and cement procedures: Variolink Veneer and AllCem Veneer. For baseline, water was applied between the ceramic disks and their respective backgrounds to achieve the control group. This set was subjected to color measurement using an intraoral measurement device (T0). The try-in was inserted between background and ceramic, and this set was subjected to color measurement (T1). After adhesive procedures, the ceramic disk was placed under cement, and color measurement was performed with uncured cement (T2) and 24 h after light-curing (T3). Each set was immersed in distilled water and thermal-cycled, with color measurement being performed after 10,000 (T4) and 20,000 (T5) cycles. Color differences were calculated by CIELab (rEab) and CIEDE2000 (rE00). Data were analyzed by two-way ANOVA for repeated measurements and Tukey's test (α=5%). There was color correspondence of try-in and resin cement for the Variolink system, regardless of the ceramic thickness (p > 0.05). For the AllCem system, the thickness significantly influenced the color measurement (p < 0.001). The Variolink system also demonstrated color stability after 20,000 thermal cycles with rEab < 3.46 and rE00 < 2.25. It was concluded that the color correspondence between a try-in and its respective cement may vary according to resin cement composition.


Assuntos
Cor , Porcelana Dentária/química , Cimentos de Resina/química , Cerâmica/química , Facetas Dentárias , Técnicas In Vitro , Teste de Materiais , Pomadas/química
17.
Quintessence Int ; 50(9): 712-719, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31482154

RESUMO

The injectable composite resin technique is an indirect/direct method that uses a transparent silicone index for accurate and predictable translation of a diagnostic wax-up into composite restorations without the need for tooth preparation. This case report involves a 22-year-old man who presented with esthetic and functional problems associated with diastemas and insufficient tooth visibility. Clinical examination revealed inadequate canine guidance in lateral excursion. The treatment plan included the fabrication of composite veneers for the maxillary incisors and canines. A wax-up was prepared by simulation of functional movements on an articulator, and a transparent silicone index was prepared after checking a mock-up in the oral cavity. The teeth were restored with flowable composite injected and polymerized through the transparent silicone index. The conventional technique was modified by cutting the silicone index at the gingival margin, using individual mock-ups as space holders, and the use of gingival retraction cords. The final outcomes were elongated teeth for increased visibility, closed diastemas, and reshaped canines for adequate guidance in lateral excursion. A protective splint for night-time wear was fabricated and delivered to ensure long-term stability. The patient did not exhibit any soft tissue inflammation or significant wear during a 24-month follow-up period. The technique described is minimally invasive and inexpensive, and it can be used for definitive as well as translational restorations. The treatment goals are to establish adequate function and esthetics, with advantages including minimal tooth structure loss and cost-effectiveness. Stable and predictable results can be achieved with proper planning and a careful workflow.


Assuntos
Diastema , Estética Dentária , Adulto , Resinas Compostas , Facetas Dentárias , Seguimentos , Humanos , Incisivo , Masculino , Adulto Jovem
18.
Dent Mater ; 35(11): 1576-1593, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31522759

RESUMO

OBJECTIVES: Yttria Partially Stabilised Zirconia (YPSZ) is a high strength ceramic which has become widely used in porcelain veneered dental copings due to its exceptional toughness. Within these components the residual stress and crystallographic phase of YPSZ close to the interface are highly influential in the primary failure mode; near interface porcelain chipping. In order to improve present understanding of this behaviour, characterisation of these parameters is needed at an improved spatial resolution. METHODS: In this study transmission micro-focus X-ray Diffraction, Raman spectroscopy, and focused ion beam milling residual stress analysis techniques have, for the first time, been used to quantify and cross-validate the microscale spatial variation of phase and residual stress of YPSZ in a prosthesis cross-section. RESULTS: The results of all techniques were found to be comparable and complementary. Monoclinic YPSZ was observed within the first 10µm of the YPSZ-porcelain interface with a maximum volume fraction of 60%. Tensile stresses were observed within the first 150 µm of the interface with a maximum value of ≈300 MPa at 50 µm from the interface. The remainder of the coping was in mild compression at ≈-30MPa, with shear stresses of a similar magnitude also being induced by the YPSZ phase transformation. SIGNIFICANCE: The analysis indicates that the interaction between phase transformation, residual stress and porcelain creep at YPSZ-porcelain interface results in a localised porcelain fracture toughness reduction. This explains the increased propensity of failure at this location, and can be used as a basis for improving prosthesis design.


Assuntos
Porcelana Dentária , Prótese Dentária , Análise do Estresse Dentário , Facetas Dentárias , Teste de Materiais , Estresse Mecânico , Propriedades de Superfície , Ítrio , Zircônio
19.
Rev. Cient. CRO-RJ (Online) ; 4(2): 67-71, May-Aug. 2019.
Artigo em Inglês | LILACS, BBO - Odontologia | ID: biblio-1024941

RESUMO

Introduction: The prefabricated composite resin veneers are prepolymerized laminates of composite that appeared in the market to simplify the restorative procedure, reducing working time. They are extremely thin veneers fabricated in several sizes, which allows performing restorations with high aesthetic standard in anterior teeth using a minimally invasive technique. Objectives: This study aimed to show the use of prefabricated resin veneers in the re-anatomization and recovery of dental aesthetics of a young patient with history of fracture and darkening of anterior teeth after aesthetic periodontal surgery. Case report: The patient attended the clinic with a smile complaint and the clinical examination showed tooth 11 with cervical fracture, tooth 21 with color change and caries infiltration, and tooth 22 with inclination of the distal surface toward the palatal region. As treatment, was opted for the use of prefabricated composite resin veneers. Conclusion: The aesthetic results of this case were highly satisfactory, especially when compared with clinical time, cost, and the laboratory work of ceramic veneers, showing the quality and advantages of this material.


Introdução: As facetas pré-fabricadas de resina composta são laminados prépolimerizados de compósito que surgiram no mercado para simplificar o procedimento restaurador, reduzindo o tempo de trabalho. São facetas extremamente finas, fabricadas em diversos tamanhos, com as quais é possível realizar restaurações com alto padrão estético em dentes anteriores através de uma técnica minimamente invasiva. Objetivo: Esse trabalho teve como objetivo demonstrar o uso de facetas pré-fabricadas de resina na reanatomização e recuperação da estética dentária de um paciente jovem com histórico de fratura e escurecimento dos dentes anteriores, após cirurgia estética periodontal. Relato de caso: Paciente compareceu à clínica com queixa do sorriso e ao exame clínico, observou-se dente 11 com fratura cervical, dente 21 com alteração de cor e infiltração por cárie e dente 22 com inclinação da face distal para palatina. Como tratamento, foi optado pela utilização das facetas pré-fabricadas de resina composta. Conclusão: Os resultados estéticos deste caso foram altamente satisfatórios, principalmente quando comparados ao tempo clínico, custo e trabalho laboratorial de facetas de cerâmica, mostrando a qualidade e as vantagens desse material.


Assuntos
Estética Dentária , Fraturas dos Dentes , Resinas Compostas , Facetas Dentárias
20.
Dent Mater ; 35(10): 1498-1505, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31400983

RESUMO

OBJECTIVES: Understand how cooling protocols control the microstructure and mechanical properties of veneering porcelains. METHODS: Two porcelain powders were selected, one used to veneer metallic frameworks (VM13) and one for zirconia frameworks (VM9). After the last firing cycle, the monolithic specimens were subjected to two cooling protocols: slow and fast. Flexural strength (FS) was evaluated by three-point beam bending and fracture toughness (KIC) was evaluated by the single-edge V-notch beam (SEVNB) method. Scanning electron microscopy (SEM) was performed to determine the leucite crystal volume fraction (%), particle size, and matrix microcrack density. The results were compared by analysis of variances (ANOVA) and Tukey's multiple comparison test. RESULTS: The mechanical properties were significantly (p<0.05) higher for the VM13 porcelain (FS=111.0MPa, KIC=1.01MPa.√m) compared to VM9 (FS=79.6MPa, KIC =0.87MPa.√m) regardless of cooling protocol due to ∼250% higher volume fraction of leucite crystals. The slow cooled VM13 and fast cooled VM9 resulted in the highest and lowest mechanical properties, respectively, while the VM9 slow cooled properties were similar to the VM13 fast cooled. The SEM revealed that the slow cooling significantly increased the volume fraction of leucite crystals by 33-41 %. Across both porcelains, a significant linear correlation between both mechanical properties (strength and toughness) and leucite crystal content was found. Slow cooling was also associated with increased crystal growth resulting in more matrix microcracking. SIGNIFICANCE: Controlled crystallization using slow cooling can be applied as a means of strengthening dental porcelains. However, the benefits of slow cooling may be partially offset by increasing the microcrack density in the glass matrix. To achieve the maximum benefit of slow cooling, it is recommending to develop heat treatments to produce porcelain with fine-grained and homogenously dispersed leucite crystals to achieve minimal glass matrix microcracking.


Assuntos
Cerâmica , Facetas Dentárias , Silicatos de Alumínio , Cristalização , Porcelana Dentária , Análise do Estresse Dentário , Teste de Materiais , Microscopia Eletrônica de Varredura , Propriedades de Superfície
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