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1.
Compend Contin Educ Dent ; 42(4): 188-191, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33960804

RESUMO

Enduring glass-ceramic restorations greatly depend on the quality of adhesion of the crown to enamel and dentin. Proper isolation is vital to the success of bonded ceramic restorations. The rubber dam has long been considered the primary method of preventing contamination of the operating field, a crucial requisite for adhesion. However, many dentists do not use rubber dam isolation due to its penchant for slowing down procedures. The authors present a case report that describes a technique for the indirect bonding of a ceramic restoration to a maxillary first molar using rubber dam isolation in conjunction with a floss ligature,a method that is aimed at optimizing operator effectiveness and efficiency.


Assuntos
Lítio , Diques de Borracha , Cerâmica , Coroas , Esmalte Dentário , Porcelana Dentária , Humanos , Dente Molar , Cimentos de Resina
2.
J Prosthet Dent ; 125(5): 804.e1-804.e6, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33934821

RESUMO

STATEMENT OF PROBLEM: Agreement on the perfect virtual cement space value for computer-aided design and computer-aided manufacturing (CAD-CAM) implant-supported resin-ceramic crowns with the best marginal adaptation is lacking. The range of cement gap settings in some CAD design software programs is wide (0 to 200 µm), and manufacturer recommendations regarding the best cement gap setting for certain types of ceramics is not specific. PURPOSE: The purpose of this in vitro study was to evaluate the effect of virtual cement gap settings on the marginal fit of cemented resin-ceramic crowns on implant abutments. MATERIAL AND METHODS: Thirty implant analogs and matching stock abutments were coupled and implanted into autopolymerizing acrylic resin blocks. Three groups (n=10) of resin-ceramic molar crowns with 3 different virtual cement space settings (40, 60, and 100 µm) were designed by using a CAD design software program. The crowns were cemented over their corresponding abutments under a static load by using a specially designed cementing device. A scanning electron microscope was used to measure the mean vertical marginal gap (MG) for each group, where a total of 120 measurements for each of the 3 groups (12 sites per crown and 10 crowns per group) were evaluated. One-way analysis of variance and the post hoc Tukey pairwise comparison tests were used to analyze the data (α=.05). RESULTS: A significant difference (P<.001) was found between the MG values of the resin-ceramic implant-supported crowns fabricated by using the 3 cement space settings. The smallest MG was obtained with the 60-µm setting as compared with the 40-µm and 100-µm settings. CONCLUSIONS: A limited inverse relation was found between the MGs of CAD-CAM-fabricated resin-ceramic implant-supported crowns and the cement gap settings in the exocad software program. The smallest MGs were obtained when a 60-µm cement space value was used (P<.001).


Assuntos
Implantes Dentários , Adaptação Marginal Dentária , Cerâmica , Desenho Assistido por Computador , Coroas , Porcelana Dentária , Planejamento de Prótese Dentária
3.
Shanghai Kou Qiang Yi Xue ; 30(1): 7-12, 2021 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-33907771

RESUMO

PURPOSE: To provide theoretical basis for clinical CAD/CAM restorations with a comparison of the fracture strength between two chairside CAD/CAM immediate restorative materials (IPS e.max CAD and Vita Enamic) with different occlusal thickness in vitro. METHODS: IPS e.max CAD and Vita Enamic full-crowns with occlusal thicknesses 1.5/2.0/2.5 mm were fabricated with CEREC and adhesively seated to dies customized by manufacturer (n=42). All specimens were stored in distilled water at 37 ℃ for 24 h. Later, static fractural loading was performed. The fracture surface was observed through scanning electron microscope (SEM) and energy dispersive spectrum (EDS). The composites of two materials were detected by X-Ray diffraction (XRD) techniques. The results of fracture strength were analyzed by one-way ANOVA and t-test via SPSS 20.0 software package. RESULTS: With the increase of occlusal thickness, the fracture strength of IPS e.max CAD increased remarkably. However, the Vita Enamic's fracture strength remained the same with no significant difference. With the occlusal thickness increased from 1.5 to 2.0 mm, there was no significant difference in the fracture strength between IPS e.max CAD group and Vita Enamic group. As the thickness increased from 1.5 to 2.0 mm, the fracture strength of IPS e.max CAD group was significantly higher than that of Vita Enamic group. The results of SEM showed that the filler particles of IPS e.max CAD were smaller compared to that of Vita Enamic. Cone cracks were mainly found in the fracture surface of IPS e.max CAD, while radical cracks appeared in Vita Enamic. EDS showed the metal oxide and SiO2 in Vita Enmic was significantly higher than that in IPS e.max CAD. XRD showed that the primary crystal phase of IPS e.max CAD was lithium silicate, while Vita Enamic was amorphous. CONCLUSIONS: Both IPS e.max CAD and Vita Enamic can meet the standard of clinical application as the occlusal thickness reaches 1.5 mm. IPS e.max CAD showed better fracture resistance when the thickness was greater than 2.0 mm.


Assuntos
Porcelana Dentária , Resistência à Flexão , Cerâmica , Desenho Assistido por Computador , Teste de Materiais , Dióxido de Silício , Propriedades de Superfície
4.
Stomatologiia (Mosk) ; 100(2): 97-102, 2021.
Artigo em Russo | MEDLINE | ID: mdl-33874669

RESUMO

The analysis of modern scientific data on traditional and adhesive fixation of zirconia restorations, adhesion of various cements to zirconium dioxide, methods of surface preparation of ceramic restorations is presented. Micromechanical methods of preparation for cementation of the surface of a zirconia dental prosthesis are discussed in Part 1.


Assuntos
Colagem Dentária , Cimentos de Resina , Cerâmica , Cimentos Dentários , Porcelana Dentária , Análise do Estresse Dentário , Humanos , Teste de Materiais , Propriedades de Superfície , Zircônio
5.
Oper Dent ; 46(1): 4-14, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33882132

RESUMO

CLINICAL RELEVANCE: Lithium disilicate veneers for esthetic restorations show great accuracy and similarity, regardless of the type of fabrication technique.


Assuntos
Cerâmica , Temperatura Alta , Desenho Assistido por Computador , Coroas , Porcelana Dentária , Planejamento de Prótese Dentária , Teste de Materiais
6.
Oper Dent ; 46(1): 25-44, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33882133

RESUMO

CLINICAL RELEVANCE: Composite resin or ceramic inlays, onlays, and overlays can achieve high long-term survival and success rates.


Assuntos
Resinas Compostas , Restaurações Intracoronárias , Cerâmica , Porcelana Dentária
7.
Int J Prosthodont ; 34(2): 163-172, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33882563

RESUMO

PURPOSE: To systematically evaluate and compare the clinical performance of lithium disilicate (LDS)- and zirconium dioxide (ZrO2)-based ceramic monolithic crowns in the posterior dentition. MATERIALS AND METHODS: Treatment was administered by two experienced general dental practitioners in two public dental health care clinics. Forty-four patients received 60 crowns randomized to be either LDS or ZrO2 and cemented with resin cement. Evaluations were performed after 3 years using California Dental Association criteria. RESULTS: The mean follow-up time was 40 months (range: 31 to 50). No crown fractured during the observation time, and no chip-off fractures occurred. The success rate for ZrO2 was 80%, and the survival rate was 93.3%. For LDS, the success rate was 89.7%, and the survival rate was 100%. Survival after 3 years for all crowns together was 96.6%, and success was 84.7%. There was no significant difference between the two materials. CONCLUSION: Crowns made of monolithic translucent ZrO2 and LDS show equal and promising clinical results from a short-term perspective. There seems to be a difference between how patients and professionals rate crowns concerning esthetics (color and shape), with patients rating the restorations more favorably.


Assuntos
Planejamento de Prótese Dentária , Odontólogos , Desenho Assistido por Computador , Coroas , Porcelana Dentária , Falha de Restauração Dentária , Seguimentos , Humanos , Papel Profissional , Estudos Prospectivos , Zircônio
8.
Artigo em Inglês | MEDLINE | ID: mdl-33800420

RESUMO

Dental laboratories (LABs) are integral to the performance of a dentist in providing successful oral rehabilitation. The aim of this study was to compare the adaptation, contour, contacts, and shade matching of different government and commercial dental LABs in the fabrication of porcelain fused to metal (PFM) crowns. Thirty-two dental LABs were selected to fabricate PFM crowns (one PFM crown each). Marginal adaptation, contour, proximal contacts, and shade matching were evaluated. Evaluation of the crowns' quality was performed following modified USPHS/FDI criteria. Visual and colorimeter assessments were employed to evaluate shade matching. Differences between groups were examined by Pearson's Chi-square and Fisher's exact test. The quality of marginal adaptation of crowns was good in 81.25%, however the quality of contours, contacts, and shade matching was compromised in 43.75%, 59.38%, and 39% of all LABs, respectively. Visual and colorimeter shade matching was acceptable in 62.5% and 80% of LABs in the cervical third and middle third regions of crowns, respectively, however in the incisal third the shade matching was unacceptable in nearly 60% of LABs. Commercial laboratories showed significantly better contours and shade matching, but not marginal adaptation. However, no significant differences were found in comparison of proximal contacts between the groups.


Assuntos
Porcelana Dentária , Dente , Cor , Coroas , Laboratórios Odontológicos
9.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 56(4): 342-348, 2021 Apr 09.
Artigo em Chinês | MEDLINE | ID: mdl-33832035

RESUMO

Objective: To explore the effect of subpressure on the bonding strength of resin to polycrystalline particulates modified zirconia ceramic. Methods: One hundred and twenty pre-sintered zirconia discs were prepared and divided into the control group, the sandblasting group and the 30, 50, 70 s acid etching group (24 per group) by the random number table method. There was no additional treatment in the control group and sandblasting group before sinering. The 30, 50, and 70 s acid etching groups were immersed in HF for 30, 50, 70 s, respectively, and then they were placed into CaCl2 solution for 90 s and dipped in NaOH solution at 80 ℃ for 2 h. After sintering, the sandblasting group was subjected to sandblasting. The surface tomography and roughness were tested. According to whether subpressure was applied or not after the adhesives were applied, each group was randomly divided into two subgroups with a random number table: a subpressure subgroup and a normal pressure subgroup (12 per subgroup). Resin columns were bonded to these specimens. Shear bonding strength (SBS) test was conducted and the bonding interface, fracture surface and failure mode were analyzed. Results: The surface of control group was smooth, and its roughness was (0.24±0.11) µm. The rough surface was formed after sandblasting in the sandblasting group, and its roughness was (0.95±0.12) µm. The surface roughness of 30, 50, 70 s acid etching groups [(0.60±0.15), (1.04±0.11), (1.57±0.16) µm] increased as the HF immersion time prolonged, and the difference in surface roughness of zirconia specimens among each group was statistically significant (P<0.05). The SBS values between zirconia and resin of all the subpressure subgroups, namely: the control group, the sandblasting group, and the 30, 50, 70 s acid etching group [(13.56±1.19), (20.98±2.11), (17.37±2.44), (24.19±2.97), (21.36±2.16) MPa] were significantly stronger than those in the normal pressure subgroups, namely: the control group, sandblasting group, 30, 50, 70 s acid etching group [(10.74±0.93), (18.47±2.14), (14.81±1.54), (20.74±2.56), (17.75±2.54) MPa] (P<0.05). No obvious gaps and bubbles were observed in the bonding interfaces in subpressure subgroups. The proportion of mixed failure was significantly increased after applying subpressure (P<0.05). Conclusions: The subpressure can effectively enhance the bonding strength between the resin and polycrystalline particulates modified zirconia ceramic and improve the bonding effect.


Assuntos
Colagem Dentária , Cimentos de Resina , Cerâmica , Cimentos Dentários , Porcelana Dentária , Teste de Materiais , Microscopia Eletrônica de Varredura , Resistência ao Cisalhamento , Propriedades de Superfície , Zircônio
10.
J Prosthet Dent ; 125(4): 691.e1-691.e7, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33820617

RESUMO

STATEMENT OF PROBLEM: The extrinsic characterization with pigments and glaze application on the surface of ceramic restorations promotes individualization and esthetics. However, whether this characterization is resistant to toothbrushing abrasive wear is unclear. PURPOSE: The purpose of this in vitro study was to investigate the abrasive wear resistance of characterized and glazed resin-modified ceramic with different surface treatments before characterization. MATERIAL AND METHODS: Eighty rectangular specimens (10×8×6 mm) were precision cut from Vita Enamic and randomly divided in 4 groups as per the surface treatment before the characterization technique. These groups included the following: no additional treatment or polishing only, acid etching, airborne-particle abrasion, and self-etching silanization. For each surface treatment, 2 subgroups were created considering the presence or absence of the glaze layer after shade characterization, totaling 8 groups (n=10). The specimens were submitted to toothbrushing simulation (150 000 cycles, 2.45-N, 180 strokes per minute) with a soft and straight toothbrush and a solution of toothpaste and distilled water (250 g/L). After each 50 000 cycles, the wear of the characterized surface was measured by using a contact profilometer in µm which was equivalent to 5, 10, and 15 years of simulated toothbrushing. The rates were analyzed by using 3-way ANOVA and the post hoc Tukey test (α=.05). Scanning electron microscopy analysis was performed to access the surface profile between the evaluated periods. RESULTS: The mean wear rate (Rz) of the characterized surface was affected by the isolated factors, including surface treatment, glaze, and time (P<.001), with no interactive effects noted. A higher mean value of Rz was observed for polishing only (12.9 ±4.4 µm), followed by airborne-particle abrasion (10.2 ±4.5 µm), acid etching (9.4 ±2.4 µm), and then self-etching silanization (7.6 ±2.9 µm). Mean wear rate was also increased by the glaze (11.1 ±4.7 µm) compared with its absence (9 ±3.2 µm) and by the length of time, with 15 years (11.3 ±4.5 µm) followed by 10 years (9.8 ±4.0 µm) and 5 years (9 ±3.6 µm). The scanning electron microscopy images showed similar worn surfaces for each subgroup, glaze removal after 150 000 cycles, and surface homogeneity in function of time. CONCLUSIONS: Self-etching silanization was found to be the treatment suitable for reducing the wear of characterized resin-modified ceramic during prolonged brushing of more than 5 years. Glaze application did not protect the characterization from surface wear, regardless of the ceramic surface treatment performed on the specimens.


Assuntos
Porcelana Dentária , Escovação Dentária , Cerâmica , Estética Dentária , Teste de Materiais , Microscopia Eletrônica de Varredura , Propriedades de Superfície
11.
Gen Dent ; 69(3): 24-29, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33908874

RESUMO

This study evaluated the failure load and the shear bond strength of 4 block materials indicated for computer-aided design/computer-aided manufacturing (CAD/CAM) of dental veneers: lithium disilicate, feldspathic ceramic, polymer-infiltrated ceramic, and nanohybrid composite. The tested hypothesis was that the material that combined an elastic modulus similar to that of enamel with the highest bond strength values would present the highest failure load. From prefabricated CAD/CAM blocks, disc-shaped specimens (6.0 × 0.7 mm; n = 10) and cylinders (2.4 × 2.5 mm; n = 10) were fabricated for load-to-failure and shear bond strength tests, respectively. Materials were adhesively bonded to flattened bovine enamel surfaces, stored in distilled water at 37°C for 90 days, and subjected to thermocycling (2000 cycles of 5°C to 55°C). Discs of restorative material were bonded to enamel and subjected to an increasing load that was applied perpendicular to the bonding interface until catastrophic failure occurred. A chisel was used to apply an increasing load parallel to the adhesive interface between the enamel and a cylinder of restorative material to measure shear bond strength. Data were subjected to a Weibull analysis and 1-way analysis of variance followed by a Tukey post hoc test (α = 0.05). The type of restorative material significantly affected the (mean [SD]) failure load when bonded to enamel (P = 0.006): polymer-infiltrated ceramic (1167.9 [310.2] N) = feldspathic ceramic (1115.0 [382.0] N) = nanohybrid composite (1067.3 [251.0] N) > lithium disilicate (786.2 [304.5] N). The type of restorative material also significantly affected the (mean [SD]) bond strength to enamel (P < 0.001): lithium disilicate (32.81 [11.19] MPa) = polymer-infiltrated ceramic (27.04 [7.65] MPa) > feldspathic ceramic (21.11 [9.16] MPa) > nanohybrid composite (9.08 [3.66] MPa). The polymer-infiltrated ceramic presented the best performance when bonded to enamel.


Assuntos
Colagem Dentária , Cimentos de Resina , Animais , Bovinos , Cerâmica , Esmalte Dentário , Porcelana Dentária , Análise do Estresse Dentário , Humanos , Teste de Materiais , Resistência ao Cisalhamento , Propriedades de Superfície
12.
Gen Dent ; 69(3): 68-72, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33908882

RESUMO

The fracture of restorations used for diastema closure is a clinical concern. The objective of this study was to perform a finite element-based comparative analysis of functional stress patterns in composite resin veneer restorations used for diastema closure to determine the influence of factors such as the preparation design, proximal extension, loading level, and vector of stress (loading angle). Three-dimensional finite element stress analysis was performed on a maxillary central incisor model to examine the stress distribution resulting from a nanofilled composite veneer restoration with 4 different extensions of unsupported composite (0.5, 1.0, 1.5, or 2.0 mm) and 2 different preparation designs (partial or full) under 3 loads (50, 150, or 250 N) and 3 loading angles (60°, 90°, or 125°). The maximum stress was found to be concentrated on the full-preparation design with a 0.5-mm mesial extension under a 250-N load and 60° loading angle. The minimum stress was found with the partial-preparation design with a 0.5-mm mesial extension under a 50-N load and 90° loading angle. Based on the results of the present study, a partial-preparation design is preferred when nanofilled composite resins are used for diastema closure.


Assuntos
Diastema , Resinas Compostas , Porcelana Dentária , Análise do Estresse Dentário , Facetas Dentárias , Diastema/terapia , Análise de Elementos Finitos , Humanos , Estresse Mecânico
13.
J Adhes Dent ; 23(2): 91-110, 2021 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-33825424

RESUMO

PURPOSE: The goals of this review are (1) to describe the evidence behind the use of ceramics vs composite resin to restore teeth with anterior veneers using a minimally-invasive strategy; and (2) to discuss the choice of materials and techniques for anterior veneer restorations. OVERVIEW: In recent years new adhesive restorative materials and techniques have been introduced in dentistry, including nanofilled composite resins for direct restorations, new ceramic materials that combine esthetics and strength, and polymer/ceramic materials for indirect restorations that are fabricated chairside using CAD/CAM technology, allowing the dentist to design, mill, and cement the restoration in one session. In spite of the novelty and new technology behind the introduction of new materials, the available evidence that backs some of these materials does not justify their use over similar materials or techniques that have been used by dentists for some years. Notwithstanding the success of laminate veneers and the popularity of new materials and digital techniques, the classical direct composite resin veneer is still very popular among clinicians and taught in dental schools and continuing education courses. Direct composite resin veneers are usually more affordable than indirect veneers, less invasive of the tooth structure, and easier to repair. Current composite resin materials can be finished to a tooth-like appearance, but they are susceptible to alterations of the surface gloss and potential discoloration of the composite resin. On the other hand, the preparation for indirect veneers is generally more invasive and the respective restorations are more difficult to repair. In addition, the esthetic outcome of bonded ceramic restorations still depends on the clinical behavior of the dentin adhesive and resin luting cement used to bond the restoration to the tooth structure. CONCLUSIONS: The ultimate goals of any restorative treatment are to restore function and esthetics, prevent recurrent caries lesions and bacterial leakage into the pulp space, save tooth structure, and promote the well-being of our patients. The armamentarium of new dental materials for esthetic clinical procedures has increased exponentially in the last few years. The use of different materials and techniques for anterior veneer restorations must be based on sound evidence rather than on the marketing hype or testimonials.


Assuntos
Resinas Compostas , Facetas Dentárias , Cerâmica , Materiais Dentários , Porcelana Dentária , Humanos , Cimentos de Resina
14.
J Adhes Dent ; 23(2): 113-119, 2021 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-33825425

RESUMO

PURPOSE: To evaluate the influence of different surface treatments of two CAD/CAM glass ceramics on surface topography, shear bond strength of composite cement, flexural strength, and elastic modulus. MATERIALS AND METHODS: Two ceramics were evaluated: lithium-disilicate (LDS) and zirconia-reinforced lithium silicate (ZLS) glass ceramics. Glass ceramics were sintered and the surfaces were sandblasted (SBL) or etched with 9% hydrofluoric acid for 10 s (HF10), 20 s (HF20) or 30 s (HF30). The treated surfaces were analyzed using scanning electron microscopy (n = 3) to evaluate the etching pattern. For bond strength testing, ceramic samples were silanized after treatments and an adhesive was applied to the surface. Afterwards, a silicone mold was used to build composite-cement cylinders, which were tested after 24 h or one year of water storage (n = 10). Flexural strength and modulus were assessed using a 3-point bending test (n = 15). The data were subjected to statistical analysis at a pre-set α = 0.05. RESULTS: SBL and HF resulted in different surface topographies. Increased HF etching time influenced the surface dissolution level and exposition of crystals for LDS, while no effect of etching time was observed for ZLS. After one year, the bond strength to LDS significantly decreased, regardless of treatments. For ZLS, HF10 and HF20 showed stable bond strengths over time. SBL yielded the lowest bond strength for both ceramics and statistically significantly reduced the flexural strength of ZLS. The flexural strength and elastic modulus of ceramics were not affected by different etching times. CONCLUSION: Bonding stability depended on the glass ceramic and the pretreatment method employed. HF etching did not change the mechanical properties of the ceramics and is indicated as a ceramic treatment for bonding.


Assuntos
Colagem Dentária , Ácido Fluorídrico , Cerâmica , Porcelana Dentária , Resistência à Flexão , Teste de Materiais , Cimentos de Resina , Propriedades de Superfície
15.
J Adhes Dent ; 23(2): 133-143, 2021 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-33825427

RESUMO

PURPOSE: To evaluate the effect of different etching times of a self-etching ceramic primer on the microshear bond strength (µSBS) and topographic surface pattern of a lithium-disilicate glass-ceramic. MATERIALS AND METHODS: Ceramic slices were subjected to an in-lab simulation of CAD/CAM milling and randomly allocated to 10 groups (n = 35) considering two factors: "surface treatment" in 5 levels - one control group (5% hydrofluoric acid + silane application [HF5+SIL]), and 4 experimental groups using ceramic etching/primer (Monobond Etch & Prime, E&P) with different passive application times (40 s, 2 min, 5 min, or 10 min); and "aging" factor in 2 levels - short-term (after 24 h), or long-term (storage for 180 days + 12,000 thermal cycles). Composite cement cylinders were built and µSBS tests were run in a universal testing machine. The failure patterns were categorized, and complementary analyses with SEM and Atomic Force Microscopy (AFM) were performed. RESULTS: The groups showed statistically similar bond strengths in the short term (range 22.4 to 25.1 MPa). However, only the E&P 20s+40s (19.3 MPa) and E&P 20s+5min (21.5 MPa) groups maintained stable bond strength in the long term, and HF5+SIL (17.1 MPa) presented statistically significantly lower values than did E&P 20s+5min. The failure pattern was predominantly adhesive. The increased application time of the ceramic primer promoted greater dissolution of the glass matrix; thus, the E&P 20s+10min group presented the most complex surface characteristics in the fractal dimension analysis. CONCLUSION: The self-etching ceramic primer can be used as an alternative to classical conditioning with HF plus silane, promoting stable bond strength for etching times of 40 s or 5 min of passive application.


Assuntos
Colagem Dentária , Lítio , Cerâmica , Porcelana Dentária , Ácido Fluorídrico , Teste de Materiais , Cimentos de Resina , Silanos , Propriedades de Superfície
16.
Beijing Da Xue Xue Bao Yi Xue Ban ; 53(2): 402-405, 2021 Mar 01.
Artigo em Chinês | MEDLINE | ID: mdl-33879918

RESUMO

OBJECTIVE: To evaluate the effects of different edge compensation angles on the fracture strength of multilayer zirconia all-ceramic crowns and traditional uniform zirconia all-ceramic crowns. METHODS: The resin tooth preparation specimen of the mandibular first molar with a knife-edge was fabricated. A 3D digital model of the specimen was obtained by scanning it with a 3D dental model scanner. The 3D digital model was imported into computer aided design (CAD) software, and three 3D digital models of the full crown with the same surface shape are designed with the edge compensation angles of 30°, 45° and 60°, respectively. Then, the designed 3D digital model is imported into computer aided manufacturing (CAM) software. Three kinds of multilayer and homogeneous zirconia all-porcelain crowns with different edge compensation angles were fabricated, 10 each for a total of 60. The fracture load of each crown was measured under the electronic universal testing machine. RESULTS: Fracture load of multilayer and uniform zirconia all-ceramic crowns, (4 322.86±610.07) N and (5 914.12±596.80) N in the 30° group, (5 264.82±883.76) N and (5 220.83±563.38) N in the 45° group and (4 900.42±345.41) N and (5 050.22±560.24) N in the 60° group, respectively. The fracture load of multi-layer zirconia all-ceramic crowns in the 30° group was significantly lower than that of homogeneous zirconia all-ceramic crowns(P < 0.05); there was no statistical significance in 45° group and 60° group(P>0.05). In the multi-layer zirconia all-ceramic crowns: the fracture load of the 30° group was significantly lower than that of the 45° group (P < 0.05); there was no significant difference between the 30° group and the 60° group, the 45° group and the 60° group (P>0.05).In uniform zirconia full crown group: the 30° group was higher than the 45° group, the 30° group was higher than the 60° group (P < 0.05), and there was no significant difference between the 45° group and the 60° group (P>0.05). CONCLUSION: The fracture loads of three kinds of uniform and multilayer zirconia all ceramic crowns with different edge compensation angles can meet the clinical requirements. A smaller edge compensation angle is recommended when using traditional zirconia all-ceramic crowns, while 45° is recommended when using multi-layer zirconia all-ceramic crowns.


Assuntos
Cerâmica , Resistência à Flexão , Desenho Assistido por Computador , Coroas , Porcelana Dentária , Planejamento de Prótese Dentária , Falha de Restauração Dentária , Análise do Estresse Dentário , Teste de Materiais , Zircônio
17.
Hua Xi Kou Qiang Yi Xue Za Zhi ; 39(1): 115-120, 2021 Feb 01.
Artigo em Inglês, Chinês | MEDLINE | ID: mdl-33723947

RESUMO

Many patients with large-area tooth defect need cast post-core crown restoration. However, the color defect of the cast post-core will affect the final restorative result, especially that of the anterior teeth. A new technology of color masking by applying CERAMAGE polymeric porcelain to the cast metal post-core surface improves the color of a full-ceramic restoration of anterior teeth and may provide a new alternative for the aesthetic repair of anterior teeth with a large area of defective tooth.


Assuntos
Porcelana Dentária , Técnica para Retentor Intrarradicular , Cerâmica , Coroas , Estética Dentária , Humanos
18.
Br Dent J ; 230(5): 294-300, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33712779

RESUMO

Objectives To present the treatment approach for the restoration of localised anterior erosive wear using a combination of dental materials.Clinical considerations A patient presented in a private dental practice concerned about the aesthetics of his anterior teeth. The patient's history and clinical examination revealed erosive wear on the labial and palatal aspects of his maxillary central incisors and right lateral incisor. The formulated treatment plan was to restore the teeth in a conservative way. A diagnostic wax-up was performed and confirmed with the patient with chairside mock-up. The treatment provided included direct composite restorations, replacement of a porcelain-fused-to-metal crown on his left lateral incisor with a porcelain-fused-to-zirconia crown, and lithium disilicate ceramic veneers on the worn labial surfaces of the central incisors and the right lateral incisor. The preparations for the ceramic veneers were carried out with the aid of the diagnostic mock-up, thus minimising the need for tooth removal of the worn teeth.Conclusions Pre-operative planning for tooth surface loss cases can help to ensure that little or no remaining tooth structure is removed during the restorative procedures. A strict bonding protocol is crucial to ensure longevity of the restorations.


Assuntos
Facetas Dentárias , Estética Dentária , Cerâmica , Materiais Dentários , Porcelana Dentária , Humanos , Incisivo , Coroa do Dente
19.
Dent Mater ; 37(5): 894-904, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33757655

RESUMO

OBJECTIVE: Incorporating silane-coupling agent into universal adhesives (UAs) to simplify adhesive luting of glass-ceramic restorations appeared ineffective due to silane's instability in an acidic aqueous solution. This study aimed to evaluate new silane technology added to an experimental UA to be bonded to glass ceramics without separate prior silanization. METHODS: Combined silane technology, consisting of 3-(aminopropyl)triethoxysilane (APTES) and γ-methacryloxypropyltriethoxysilane (γMPTES), was incorporated into an experimental UA formulation, being referred to as ADH-XTE (3M Oral Care). Immediate and aged shear bond strength (SBS) of ADH-XTE onto as-milled ('AM'), tribochemical silica-coated ('TSC'), HF-etched ('HF'), and mirror-polished ('MP') glass-ceramic CAD/CAM blocks (IPS e.max CAD) with/without separate silanization was measured (n = 10/group). The control adhesives included Scotchbond Universal ('SBU') and Scotchbond 1 XT ('SB1-XT'). The glass-ceramic surface topography and the fractography of the SBS-debonded specimens were observed by SEM. RESULTS: Without separate prior silanization, the experimental UA ADH-XTE, containing combined APTES/γMPTES silane technology, significantly outperformed the glass-ceramic bonding efficiency of its silane-containing SBU precursor, while it performed equally effective as SBU applied with prior silanization. Upon aging, significant reduction in SBS was recorded when ADH-XTE was bonded to TSC glass-ceramic surfaces (p < 0.05), while not to HF ones. Notably, the lowest SBS was obtained when the UAs were bonded to AM and MP glass-ceramic surfaces, in particular when applied without separate prior silanization (p < 0.05). SIGNIFICANCE: The glass-ceramic bonding capacity of the new combined APTES/γMPTES silane-containing UA ADH-XTE surpassed that of its SBU precursor. HF etching remains needed to durably bond to glass-ceramics.


Assuntos
Colagem Dentária , Silanos , Cerâmica , Cimentos Dentários , Porcelana Dentária , Teste de Materiais , Cimentos de Resina , Propriedades de Superfície , Tecnologia
20.
J Med Life ; 14(1): 61-67, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33767787

RESUMO

Typically, prosthodontists adjust ceramic restorations glazed surface by grinding prior to insertion. Such alterations of surfaces are necessary for the correction of occlusal interferences. We aimed to evaluate and compare the change in flexural strength of ceramic surfaces after re-glazing and polishing. This study included 40 samples of ceramic blocks that were fabricated and glazed, and then fired in accordance with the manufacturer's recommendations. The sample was randomly divided into four groups of 10 samples each. The first group was the control group with unaltered glazed samples. The second group was abraded with an extra-fine diamond bur followed by re-glazing, and the other two groups were polished with two commercially available polishing kits after abrading them with an extra-fine diamond bur. The samples were tested for their flexural strength using a universal testing machine. On the application of the F test on the means of all the groups, a value greater than 0.05 was found, which meant that there is no statistically significant difference in flexural strength values between the groups (P-value>0.05). Since the flexural strength values of the polished group were comparable to the other groups, polishing can be used instead of re-glazing for ceramic restorations. This reduces an additional clinical appointment for the patient and saves working time.


Assuntos
Polimento Dentário , Porcelana Dentária/química , Resistência à Flexão , Teste de Materiais , Humanos , Propriedades de Superfície
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