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1.
J Environ Manage ; 253: 109655, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31654925

RESUMO

The beneficial effect of combining ozone with ceramic membrane filtration (CMF) to enhance membrane flux performances during water treatment (e.g., wastewater and drinking water) could be related to the formation of hydroxyl (HO) radicals from the interaction of ozone with ceramic membrane. To explore this effect, para-chlorobenzoic acid was used to probe HO radical activity during a combined ozone/CMF process using a 0.1 µm pore size membrane supplied by Metawater, Japan. Tests were then extended to explore the impact on bromate formation downstream CMF, a well-known undesirable by-product from ozone use in water treatment. Ozone reduction by the membrane and its module appeared to be more associated with physical degassing, but a noticeable formation of HO radicals was observed during the interaction of ozone with the ceramic membrane. CMF treatment of ozonated potable water containing bromide showed a reduced bromate formation of 50% when the water was recirculated to the filtration module containing the ceramic membrane, compared to the experiment performed with an empty module. Single pass experiments showed bromate mitigation of around 10%. The mitigation of bromate formation was attributed to reduced overall ozone exposure by deagassing effect, but also potentially from suppression of the oxidation of Br- and HOBr/BrO- to BrO3- due to the catalytic degradation of ozone via a HO radical pathway.


Assuntos
Ozônio , Poluentes Químicos da Água , Purificação da Água , Bromatos , Cerâmica , Radical Hidroxila , Japão
2.
Prim Dent J ; 8(3): 28-33, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31666170

RESUMO

With increasing patient expectation for aesthetic dental restorations, there has been a drive towards developing ceramic materials to meet this expectation. Multiple ceramic systems have been introduced over the past four decades with considerable advances in material properties. Survival rates of all-ceramic crowns differ by type of ceramic used, fabrication method and clinical indication. Zirconia and lithium disilicate are the most commonly used contemporary ceramic materials in dentistry. Survival data for these types of restorations appears to be promising; however, there is a lack of high-quality long-term clinical data on the success of these restorations. In the absence of robust longitudinal clinical research, laboratory studies have provided some useful information on the performance of ceramic restorations. Further high quality long-term clinical studies are needed to inform us of modes of failure of these restorations and the range of clinical circumstances in which each type of ceramic restoration may be used.


Assuntos
Cerâmica , Coroas , Porcelana Dentária , Falha de Restauração Dentária , Materiais Dentários , Humanos , Zircônio
3.
Hua Xi Kou Qiang Yi Xue Za Zhi ; 37(5): 476-479, 2019 Oct 01.
Artigo em Chinês | MEDLINE | ID: mdl-31721492

RESUMO

OBJECTIVE: To study the effects of universal adhesives and resin cement on the shear bond strength and durability of zirconia ceramics. METHODS: Zirconia ceramics were sintered into 20 mm×10 mm×10 mm and 10 mm×10 mm×10 mm specimens. The experiment was divided into 12 groups. The two types of specimens were bonded using two variants of resin cement (RelyX Ultimate and Clearfil SAC self-adhesive resin cement), universal adhesives (non-adhesive, Scotchbond uni-versal adhesive, and Clearfil SE One adhesive), and storage conditions (water bath and water bath-thermal cycling). The shear bond strengths were tested, and the fracture morphologies were analyzed. RESULTS: The cement (F=8.41, P<0.01) and adhesive (F=30.34, P<0.01) exerted a significant effect on the shear bond strength of zirconia, whereas storage condition showed no significant effect on this property (F=1.83, P=0.18). The lowest shear bond strength (14.02 MPa±6.86 MPa) was exhibited by the group treated with RelyX Ultimate resin cement, non-adhesive, and water bath-thermal cycling, whereas the highest shear bond strength (54.12 MPa±8.37 MPa) was displayed by the group treated with RelyX Ultimate resin cement, Scotchbond universal adhesive, and water bath-thermal cycling. CONCLUSIONS: Universal adhesives can improve the durability of the bonding of resin cement to zirconia. If non-self-adhesive resin cement is used without a universal adhe-sive, the durability of the bond will be greatly reduced.


Assuntos
Colagem Dentária , Cimentos de Resina , Cerâmica , Cimentos Dentários , Análise do Estresse Dentário , Teste de Materiais , Resistência ao Cisalhamento , Propriedades de Superfície , Zircônio
4.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 54(11): 765-769, 2019 Nov 09.
Artigo em Chinês | MEDLINE | ID: mdl-31683384

RESUMO

Objective: To investigate the color stability of computer aided design and computer aided manufacture (CAD/CAM) composite ceramic/resin cements after accelerated ageing. Methods: Twelve groups (ten samples each group) were used as experimental groups, which were composed of CAD/CAM composite ceramic of three kinds of thickness (0.50, 0.75, 1.00 mm) (Lava Ultimate) associated with resin cements (Variolink N) of four colors (A1, A3, T, BL1). Another three groups of CAD/CAM composite ceramic/resin cements of three different kinds of thickness (0.50, 0.75, 1.00 mm) were used as control groups (ten samples each group). All samples were put into the xenon lamp ageing instrument to implement accelerated ageing. Spectrophotometers were used to measure the lightness (L(*)), red green color value (a(*)) and blue yellow color value (b(*)) of all samples before and after accelerated ageing process, and the changes of color variation (ΔE) was calculated. The effect of composite ceramic thickness and resin cement color on the changes of color variation (ΔE) before and after the ageing of CAD/CAM composite ceramic/resin cement and whether there was an interaction between them were tested by two-way ANOVA. Results: Before and after accelerated ageing, the ΔE of CAD/CAM composite ceramic/resin cements were <3.3. Two-way ANOVA showed that the thickness of CAD/CAM composite ceramics had an effect on ΔE (F=27.025, P<0.001), and the color of resin cement also had an effect on ΔE (F=15.606, P<0.001), but there was no interaction between them (F=0.534, P=0.829). Conclusions: The thickness of CAD/CAM composite ceramics and the color of resin cements could both affect the color stability of composite ceramic/resin cements combination. However, the resulted color change is within the clinically acceptable range.


Assuntos
Porcelana Dentária , Cimentos de Resina , Cerâmica , Cor , Resinas Compostas , Projeto Auxiliado por Computador , Teste de Materiais , Propriedades de Superfície
5.
Stomatologiia (Mosk) ; 98(5): 72-77, 2019.
Artigo em Russo | MEDLINE | ID: mdl-31701933

RESUMO

AIM: A comparative clinical evaluation of the results of prosthetic treatment with chairside CAD/CAM crowns for molars made from hybrid ceramics VITA Enamic, blocks of feldspatic ceramics VITABlocs Mark II, blocks of leucite glass IPS Empress CAD. MATERIAL AND METHODS: The study involved 30 patients aged from 19 to 60 years old with defects in hard tissues of molars. For clinical evaluation we used 'Clinical criteria for evaluation of direct and indirect restorations' developed by FDI in 2007, which included the assessment of several aesthetic, functional and biological parameters. We also included 2 additional criteria indicators: the condition of the antagonist tooth and the hygienic condition of the prosthesis in comparison with the hygiene of natural teeth. All patients were randomized into 3 groups of 10 people. After the treatment the clinical quality assessment was carried out in the following time intervals: 30 minutes, 1, 6, 12, 18, 24 months after the fixation of the crown. RESULTS: Clinical evaluation of the results of prosthetic treatment of 30 patients with chairside CAD/CAM crowns made from three different materials did not reveal any significant difference in the clinical criteria for evaluation of direct and indirect restorations within 24 months.


Assuntos
Coroas , Porcelana Dentária , Adulto , Cerâmica , Projeto Auxiliado por Computador , Planejamento de Prótese Dentária , Dureza , Humanos , Teste de Materiais , Pessoa de Meia-Idade , Dente Molar , Adulto Jovem
6.
Zhonghua Yan Ke Za Zhi ; 55(11): 876-880, 2019 Nov 11.
Artigo em Chinês | MEDLINE | ID: mdl-31715684

RESUMO

Orbital blowout fractures can easily lead to defects of the orbital wall. In order to restore the continuity of the bone wall and avoid a series of clinical symptoms caused by orbital contents herniation or incarceration, the site of the defect should be reconstructed. The effect of reconstruction depends on the choice of surgical plan and repair material. The typical materials for bone wall defect repair include bone sheet, high density porous polyethylene, titanium mesh, absorbable polymer, bioactive ceramics and tissue engineering bone. This paper reviews the research findings and application of material for repairing of orbital blowout fracture. (Chin J Ophthalmol, 2019, 55: 876-880).


Assuntos
Fraturas Orbitárias/cirurgia , Procedimentos Cirúrgicos Reconstrutivos , Materiais Biocompatíveis , Cerâmica , Humanos , Órbita/cirurgia , Polietileno , Polímeros , Telas Cirúrgicas , Engenharia Tecidual , Titânio
7.
Am J Dent ; 32(5): 229-234, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31675190

RESUMO

PURPOSE: To evaluate the influence of ceramic laminate on color stability, surface microhardness, water sorption, and solubility of resin luting agents. METHODS: Disk-shaped specimens (10 × 2 mm) of dual-cured resin cements (RelyX ARC or RelyX Ultimate) were obtained, and a light-cured luting agent (RelyX Veneer) was used. In Experiment 1, disk-shaped resin cements (n = 10) were submitted to: I) polymerization with or without ceramic laminate (0.7 mm), and II) immersion in distilled water or coffee, 3 hours daily for 20 days. The surface microhardness loss (%SML) was determined, and the color variables were assessed by the CIE L*a*b* system (ΔE, ΔL*) and the shade guide units (ΔSGU). In Experiment 2, other disk-shaped specimens (n = 5) were submitted to polymerization with or without ceramic laminate to assess their water sorption (WS) and solubility (S). Statistical analysis was performed using 3-way ANOVA and Tukey's test for ΔE, ΔL* and %SML; Mann-Whitney, Kruskal-Wallis, and Dunn's tests for ΔSGU; and 2-way ANOVA and Tukey's test for WS and S. The significance level was set at 5%. RESULTS: No statistically significant differences among the resin cements was observed for %SML, WS, or S, regardless of stain exposure or presence of ceramic laminate during light activation. Coffee caused a significant decrease in ΔL* values. All the resin cements presented visually detectable color alteration for ΔE; however, RelyX Ultimate showed less color change after coffee exposure. RelyX ARC showed the greatest color change in water. RelyX Veneer presented the highest values of ΔSGU, compared with the other resin cements. The WS, S, and %SML of resin cements were not influenced by the staining solution or the presence of ceramic laminate during light activation; however, RelyX Ultimate resin cement presented the best color stability. CLINICAL SIGNIFICANCE: Resin cements can present color changes over time, affecting the long-term esthetic success of laminate ceramic restorations. RelyX Ultimate resin cement presented the best color stability, thus making it a suitable indication for cementing ceramic laminates.


Assuntos
Porcelana Dentária , Cimentos de Resina , Cerâmica , Cor , Teste de Materiais , Solubilidade , Água
8.
Am J Dent ; 32(5): 240-244, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31675192

RESUMO

PURPOSE: To evaluate the effect of different thicknesses of CAD-CAM ceramic sections on the polymerization of two different resin cements. METHODS: Three CAD-CAM all-ceramic restorative materials were sectioned with four different thicknesses. A total of 240 resin cement specimens were prepared from light cured and dual cure resin cements and absorption peaks were recorded. 10 samples of each resin cement were examined before and after polymerization and served as the control group. Data were analyzed using one-way ANOVA, independent t- and Tukey HSD tests (P< 0.05). RESULTS: Control group showed the highest DOC values while samples cured under Vita Enamic section with a thickness of 2 mm presented the lowest values (P< 0.05). Polymerization performed under sections of 0.5 and 1 mm thicknesses provided statistically higher values. Dual cured resin cement samples showed higher DOC values compared to light cured resin cement samples. IPS Empress CAD sections with 0.5 and 1 mm thickness exhibited statistically higher values than other ceramics of the same thickness for light cured resin cement samples. A significant difference was observed between IPS Empress CAD and Vita Enamic while comparing ceramic sections of the same thickness (P< 0.05). There was no difference for sections of 1.5 and 2 mm (P>> 0.05). CLINICAL SIGNIFICANCE: Thickness of the restorative material for an indirect restoration is a key element to determine the type of resin cement.


Assuntos
Porcelana Dentária , Cimentos de Resina , Cerâmica , Projeto Auxiliado por Computador , Teste de Materiais , Polimerização
9.
Am J Dent ; 32(5): 255-259, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31675195

RESUMO

PURPOSE: To evaluate the effects of different coping designs on maximum principal stresses in the veneering material using a finite element analysis method. METHODS: A maxillary first premolar tooth model was prepared. The primary and prepared tooth model were scanned with a 3D (three dimensional) scanner. Four different coping and veneer models were designed with 3D computer-aided design software: conventional design (DC); design with 3 mm palatal shoulder (DP); design with 1 mm buccal shoulder and 3 mm palatal shoulder (DB); and design with buccal facet (DF). After the models were designed, they were transferred to the finite element analysis (FEA) software for analyses. The middle points of the buccal, mesial, distal and palatal surfaces were determined in the cervical region. For all models, the maximum principal stress distributions and values of porcelain veneer were evaluated under centric occlusion loading and laterotrusive loading conditions with a FEA. RESULTS: The maximum principal stress area decreased gradually from model DC to model DB on the buccal cervical region under centric occlusion loading. However, models DF and DP showed similar stress distribution. The maximum principal stress at the distal point decreased from DC (14.7 MPa) to DP (13.5 MPa) and DB (9.6 MPa), whereas increased in model DF (33 MPa). Under laterotrusive loading, both the palatal maximum principal stress area and the stress value at the palatal point (model DC: 13.1 MPa, model DP: 3 MPa, model DB: 4MPa) decreased with the palatal shoulder. CLINICAL SIGNIFICANCE: Increasing the height of the palatal shoulder may be a practical and efficient approach to reduce the maximum principal stress in all-ceramic crowns. Thus, the clinical failure as chipping in the all-ceramic crowns may be reduced.


Assuntos
Cerâmica , Coroas , Adaptação Psicológica , Dente Pré-Molar , Porcelana Dentária , Análise do Estresse Dentário , Análise de Elementos Finitos , Estresse Mecânico , Zircônio
10.
Am J Dent ; 32(5): 260-264, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31675196

RESUMO

PURPOSE: To compare the bonding effect of normal dentin (ND) and caries-affected dentin (CAD) on the surface of glass-ceramics using three types of bonding systems. METHODS: 39 teeth with caries involving the superficial layer of dentin were randomly divided into three groups and two subgroups: nanoleakage group (n=5) and shear bond strength group (n=8). The infected dentin was removed, and the CAD was retained. The surface of the tooth was polished, and one 2 mm × 2 mm × 4 mm CAD block and one 2 mm × 2 mm × 4 mm ND block were made. The total-etch adhesive A, self-etch adhesive B, or self-adhesive resin adhesive C were used to bond the glass ceramics. The bonding specimens of the nanoleakage group were stained with ammoniated silver nitrate and observed. In the shear bond strength group, the maximum load of the loading head F (N) was recorded, and the shear bond strength of the specimen was calculated. RESULTS: The nanoleakage values were significantly lower than those in the CAD group. The nanoleakage value of group B was significantly higher than that of group C, and that of group C was significantly higher than that of group A. Both dentin type and adhesive type had an effect on shear bond strength; under the same adhesive system, normal dentin demonstrated higher shear bond strength than CAD. However, the shear bond strength of adhesive A was higher than the bond strengths of adhesives B and C, but there was no significant difference in shear bond strength between adhesives B and C. CLINICAL SIGNIFICANCE: This study showed that dentin type and bonding system influenced shear bond strength and nanoleakage. The total-etch adhesive system showed the best interfacial sealing and bonding effect.


Assuntos
Colagem Dentária , Adesivos Dentinários , Ataque Ácido Dentário , Cerâmica , Cimentos Dentários , Dentina , Teste de Materiais , Cimentos de Resina , Propriedades de Superfície , Resistência à Tração
11.
Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi ; 33(11): 1452-1456, 2019 Nov 15.
Artigo em Chinês | MEDLINE | ID: mdl-31650765

RESUMO

Objective: To study the preservation effect of true bone ceramics (TBC) prepared by high-temperature calcination of bovine bone on alveolar ridge of canine extraction socket. Methods: Six healthy Beagle dogs (aged 1.5-2 years) were selected to extract the second and fourth premolars of both mandibles and the second premolars of the maxilla. The left extraction socket was implanted with TBC as the experimental group, and the right side was implanted with the calcined bovine bone (CBB) as the control group, to observe the alveolar ridge preservation effect. Three dogs were euthanized after general observation at 1 and 6 months after operation respectively. After separating the maxilla and mandible, cone beam CT (CBCT) was performed to measure the average gray value of the graft site and the adjacent reference area (the area between the roots of the adjacent third premolar) and calculate the gray scale ratio between the bone graft site and the reference area. Histological observation was made on the bone graft site to evaluate the new bone formation. Results: General observation showed that the wounds of both groups were basically healed at 2 weeks after operation, and the bone graft materials were not exposed. The wounds healed well at 1 and 6 months after operation without swelling. The results of CBCT showed that the residual material was found in both groups at 1 month after operation, and no significant residual material was found in both groups at 6 months after operation, and the alveolar ridge height of the bone graft area was not significantly reduced. There was no significant difference in the bone mineral density between the experimental group and the control group. The gray scale ratios of the experimental group at 1 month and 6 months after operation were 0.97±0.14 and 0.93±0.06, respectively, and were 0.99±0.16 and 0.94±0.05 in control group, showing no significant difference between the two groups ( t=-1.030, P=0.333; t=-0.770, P=0.466). HE staining observation showed that a large number of bone graft materials did not degrade and new bone formed around the grafts in both groups at 1 month after operation; the bone graft materials were absorbed and a large number of new bones were formed in both groups at 6 months after operation. Conclusion: TBC can maintain bone mineral density and have good osteoconductivity in the alveolar ridge site preservation experiment of dogs, and can be used for alveolar ridge site preservation.


Assuntos
Perda do Osso Alveolar , Processo Alveolar , Animais , Bovinos , Cerâmica , Cães , Extração Dentária , Alvéolo Dental
12.
Braz Dent J ; 30(5): 446-452, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31596328

RESUMO

Two clinical cases are presented to explore technical differences and discusses the advantages and disadvantages of using veneered or monolithic zirconia to manufacture posterior single crowns. The first case describes the clinical steps in manufacturing a monolithic crown on a mandibular left second premolar using high translucency zirconia. It shows the use of a conservative tooth preparation based on the superior mechanical properties that this material presents as well as the final optical characteristics achieved by shading and staining. In the second case, a conventional bilayer restorative treatment was made using zirconia framework followed by veneering with feldspar ceramic on a mandibular left first molar. Recent literature indicates that each of these restorative alternatives presents specific advantages and disadvantages. Factors such as mechanical performance, fracture, esthetic characteristics, clinical success, complication rates, adhesion and antagonist wear performance are discussed comparing the two restorative assemblies. The data highlight that monolithic crowns prevent a major problem reported on bilayer restorations: the chipping of veneering ceramic. Monolithic crowns also allow minimally invasive tooth preparations, thus increasing tooth remnant preservation. However, data that support esthetic performance similarity between monolithic and bilayer assemblies are lacking, thus the predictability of use is restricted for the posterior region, as cases demanding high esthetic appeal continue to fundamentally use bilayer restorations. Failures were not found, and patient satisfaction was reported in both techniques after the 12-month follow up.


Assuntos
Coroas , Porcelana Dentária , Cerâmica , Humanos , Teste de Materiais , Zircônio
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 Dent J ; 30(5): 505-510, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31596335

RESUMO

The aim of this study was to investigate the three-dimensional wear, volumetric loss and surface roughness after chewing simulation of two glass ceramics. Lithium disilicate (LD, Emax CAD, Ivoclar) and Zirconia reinforced lithium silicate (ZLS, Vita Suprinity, Vita Zhanfabrick) discs (n=20/g) were scanned to obtain stereolithography (STL) files for each sample. All discs were submitted to chewing simulation with sliding configuration (30 N, 300,000 cycles, 6 mm and 1.7 Hz) with steatite as antagonist. The samples were then scanned again and the volume loss and the deepest defect depth was measured using the superimposed file from the baseline using three-dimensional digital parametric inspection software (GOM Inspect, Braunschweig, Germany). Surface roughness (Ra and Rz) was analyzed with a contact profilometer. Data were analyzed by one-way ANOVA and Tukey test (α=0.5%). ANOVA showed significant differences among the groups. Considering the ceramic volume loss, wear depth defect length and Rz roughness, LD (-22.09±5.57%; 0.80±0.06 µm; 3.08±1.02 µm) showed higher mean values than ZLS (-15.67±4.51%; 0.56±0.09 µm; 1.51±0.90 µm). Ra mean values were similar for both materials (p=0.064). All discs exhibited slight surface scratches along with the sliding direction with pitted wear patterns, while large cracks were observed on wear traces. These same areas can be identified in blue, overlapping the STL files before and after chewing simulation in inspection software. The linear reduction generated by sliding contact shows a graph with a similar wear pattern shape. ZLS was more resistant to wear than LD, with less volume loss and shallower surface defects.


Assuntos
Cerâmica , Mastigação , Porcelana Dentária , Teste de Materiais , Propriedades de Superfície
15.
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
16.
Int J Prosthodont ; 32(6): 544-548, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31664273

RESUMO

Recent attempts in the development of novel zirconia ceramics aim at improving its optical characteristics by increasing the yttria content to up to 5 mol% so that these ceramics can be used for the fabrication of stable and esthetic monolithic restorations. However, clinical evidence on the outcomes of such restorations is sparse. In this case report, monolithic inlays, partial crowns, tooth- and implant-supported single crowns, and fixed dental prostheses were fabricated out of a zirconia ceramic doped with 5 mol% yttria. The restorations in the present case history report showed a satisfying esthetic outcome and are in situ as inserted 18 months after insertion.


Assuntos
Estética Dentária , Zircônio , Cerâmica , Coroas , Prostodontia
17.
Artigo em Inglês | MEDLINE | ID: mdl-31613942

RESUMO

The objective of this study was to evaluate the influence of two finish lines on the fracture resistance and periodontal response of porcelain zirconia crowns. Ethical committee approval was obtained, and 50 zirconia single crowns were placed in posterior regions. Abutments were randomly distributed into two groups: Group 1 (feather-edge preparation) and Group 2 (chamfer preparation). Patients were recalled after 1 month, 6 months, and 1, 2, 3, and 4 years. The function, esthetics, and marginal adaptation of the restorations were evaluated. Bleeding on probing (BoP) and distance of margins from the bone crest were recorded. Statistical analyses were performed for survival and success rates. Group 1 had an 80% success rate (21/25 crowns) and a 96% survival rate (24/25 crowns; 1 encountered irreparable fracture of ceramic layer); Group 2 had a 76% success rate (20/25 crowns) and a 100% survival rate (25/25 crowns). Chippings were noticed on 4 crowns in Group 1 (one crown replacement). Five chippings occurred in Group 2, without any replacement. There were no statistically significant differences between the two groups. BoP was found in 18 of the 25 crowns in Group 1 (72%) and in 12 of the 25 crowns in Group 2 (48%). A statistically significant correlation between BoP and the distance of the margin to the bone crest was found. It was concluded that: (1) clinical survival and success rates of the two preparation methods on crowns are not significantly different; (2) due to the statistically significant correlation between BoP and the distance of the margin to the bone crest, margins should be placed at least 3 mm from the bone crest; and (3) higher probability of BoP is expected in cases with feather-edge preparation.


Assuntos
Coroas , Zircônio , Cerâmica , Porcelana Dentária , Planejamento de Prótese Dentária , Humanos
18.
Prog Orthod ; 20(1): 39, 2019 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-31608421

RESUMO

BACKGROUND: This study aims to develop a novel process to establish a standardized manufacturing technique of customized esthetic ceramic bracket system (CCB) which could be endowed with individual color and shape to satisfy patients' individual demands. Material characteristics and mechanical parameters of CCB were evaluated. SUBJECTS AND METHODS: CCB virtual models were designed individually according to patient's teeth morphology and clinical demands. 3D printing technology, lost-wax technology, and selected glass-ceramic ingots were employed to fabricate CCB. Scanning electron microscopy (SEM) analyses were performed to characterize the surface morphology of CCB and commercially available brackets (Clarity Advanced; Crystalline VII; Inspire ICE; Damon Q). Static and kinetic frictional resistance (FR), shear bond strength (SBS) and adhesive remnant index (ARI) scores were recorded. One-way analyses of variance (ANOVA) and post-hoc Tukey's HSD multiple tests were used for statistical analyses. RESULTS: Multi-color and multi-transparency raw materials facilitated CCB with a wide range of color options and controllable optical properties to satisfy different esthetic demands of individual orthodontic patients. CCB presented same level of FR as commercially available ceramic brackets did. No significant differences (P ≥ 0.05) of SBS were observed among CCB-ES (treated silane), Clarity Advanced and Crystalline VII groups, and CCB-E (no silane) attained the highest ARI mean score 3. In the preliminary clinical trial, CCB presented excellent color-matching and shape-matching appearances similar to natural teeth, which made it highly invisible from social intercourse distance. CONCLUSIONS: CCB were demonstrated to be an applicable labial orthodontic bracket system with optimized esthetics and biomechanics. We envision that it would be an ideal alternative for patients who pursue esthetic orthodontic treatment but were not likely to take lingual appliances or clear aligners.


Assuntos
Colagem Dentária , Braquetes Ortodônticos , Cerâmica , Estética Dentária , Humanos , Teste de Materiais , Resistência ao Cisalhamento , Propriedades de Superfície
19.
J Prosthet Dent ; 122(5): 491.e1-491.e9, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31623836

RESUMO

STATEMENT OF PROBLEM: Indirect composite resins (ICRs) have been suggested as veneering materials for implant-supported zirconia-based fixed dental prostheses; however, obtaining a durable bond between the zirconia ceramic and the ICR is a challenge. PURPOSE: The purpose of this in vitro study was to evaluate the influence of airborne-particle abrasion conditions on the bond strength between 2 kinds of zirconia (yttria-stabilized tetragonal zirconia polycrystal [Y-TZP] and ceria-stabilized tetragonal zirconia/alumina nanocomposite [Ce-TZP/A]) and an ICR. MATERIAL AND METHODS: Zirconia disks were prepared by using computer-aided design and computer-aided manufacturing (CAD-CAM) systems. Specimens were airborne-particle abraded with different particle sizes (25, 50, 90, 125 µm) and jet pressures (0.1, 0.2, 0.3, 0.4 MPa). The control group (CO) was not subjected to airborne-particle abrasion. The surface roughness (Ra) of the specimens was measured. Subsequently, the specimens were treated with a primer and bonded with a light-activated composite resin, and the shear bond strength (SBS) was tested. The obtained data were analyzed by using multivariate analysis of variance, the Spearman rank-order correlation, and the Mann-Whitney U test (α=.05). After the SBS test, the interface failure modes were observed by scanning electron microscopy, and X-ray photoelectron spectroscopy (XPS) was used to analyze the chemical changes of the zirconia surface. RESULTS: The Ra values increased significantly (P<.05) after airborne-particle abrasion with a positive correlation with both particle size and jet pressure. The airborne-particle abraded specimens exhibited significantly higher bond strength after thermocycling (P<.05) than the CO. Nevertheless, the bond strength was not significantly different among different airborne-particle abrasion treatments (P>.05). Additionally, Y-TZP had higher mean bond strength values than Ce-TZP/A. The XPS results revealed that after airborne-particle abrasion, the alumina particles mechanically adhered to the zirconia surface. CONCLUSIONS: Within the limitations of this in vitro study, airborne-particle abrasion improved the bond strength between zirconia and ICR; however, particle size or jet pressure were not influencing factors.


Assuntos
Colagem Dentária , Óxido de Alumínio , Cerâmica , Resinas Compostas , Materiais Dentários , Análise do Estresse Dentário , Teste de Materiais , Cimentos de Resina , Propriedades de Superfície , Zircônio
20.
Eur J Prosthodont Restor Dent ; 27(4): 164-171, 2019 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-31638349

RESUMO

OBJECTIVES: This in vitro study aimed to compare the internal and marginal discrepancies of endocrowns fabricated from different ceramics before and after adjustment. METHODS AND MATERIALS: Thirty-six endocrowns were fabricated from lithium disilicate (IPS e-max CAD), zirconia-reinforced lithium silicate (Suprinity), and polymer-infiltrated ceramic network (Enamic) using a CEREC intraoral scanner and milling unit. A reference point matching scan protocol was used to measure the endocrowns fit. The mixed ANOVA was used to analyze the data, and α=0.5 was considered as the significance level. RESULTS: There was no significant interaction between the fabrication materials and adjustment (P⟩0.05). Type of the materials did not change discrepancies at cavosurface, line angle, cavity wall, and pulpal floor (P⟩0.05). On the contrary, adjustment significantly decreased the discrepancies at all four sites (P⟨0.001). There were significant differences between every two sites before adjustment (P⟨0.001). After adjustment, except for cavosurface and cavity wall (P=0.058), the differences between other sites remained significant (P⟨0.001). CONCLUSIONS: IPS e-max CAD, Suprinity, and Enamic endocrowns were not significantly different regarding internal and marginal discrepancies. However, it is suggested that these materials be adjusted to fall in a clinically acceptable range to minimize the risk of caries and periodontal disease.


Assuntos
Coroas , Adaptação Marginal Dentária , Cerâmica , Projeto Auxiliado por Computador , Porcelana Dentária , Planejamento de Prótese Dentária , Teste de Materiais
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