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1.
Rev. Odontol. Araçatuba (Impr.) ; 42(2): 24-29, maio-ago. 2021. ilus
Artículo en Portugués | LILACS, BBO - Odontología | ID: biblio-1252903

RESUMEN

Na Odontologia, o tratamento adequado depende da condição clínica de cada paciente, do conhecimento do profissional e dos materiais empregados. As coroas com sistemas cerâmicos puros se apresentam como excelente alternativa restauradora, demonstrando potencial estético superior ao das coroas metalocerâmicas. Este presente estudo teve como objetivo, relatar um caso clínico onde se realizou uma reabilitação estética de dentes anteriores com coroas de cerâmica pura à base de dissilicato de lítio. O paciente apresentava falta de harmonia e estética entre os dentes anteriores 12,11,21 e 22, na qual foi planejado e executado a reabilitação com coroas E-max desses elementos, bem como a substituição das restaurações dos dentes inferiores anteriores, e também foi realizado a confecção de coroa E-max do dente 35. Concluímos que as reabilitações estéticas de dentes anteriores com coroas de sistemas cerâmicos puros à base de dissilicato de lítio se apresentam como uma excelente alternativa reabilitadora, na qual o tratamento multidisciplinar é um fator considerado essencial, possibilitando restabelecer a estética e a funcionalidade do sorriso do paciente, a fim de alcançar o êxito do tratamento reabilitador(AU)


In dentistry, the appropriate treatment depends on the clinical condition of each patient, the knowledge of the professional and the materials used. Crowns with pure ceramic systems are an excellent restorative alternative, demonstrating an aesthetic potential superior to that of metalloceramic crowns. This present study aimed to report a clinical case where an aesthetic rehabilitation of anterior teeth was performed with crowns of pure ceramic based on lithium disilicate. The patient had a lack of harmony and aesthetics between the anterior teeth 12,11,21 and 22, in which the rehabilitation with E-max crowns of these elements was planned and performed, as well as the replacement of the anterior lower teeth restorations, and was also made the E-max crown of tooth 35. We conclude that the aesthetic rehabilitation of anterior teeth with crowns of pure ceramic systems based on lithium disilicate is an excellent alternative for rehabilitation, in which multidisciplinary treatment is considered an essential factor, making it possible to restore the aesthetics and functionality of the patient's smile, in order to achieve the success of the rehabilitation treatment(AU)


Asunto(s)
Humanos , Masculino , Adulto , Cerámica , Coronas , Rehabilitación Bucal , Restauración Dental Permanente , Estética Dental , Incrustaciones
2.
Int J Comput Dent ; 24(2): 147-155, 2021 Jun 04.
Artículo en Inglés | MEDLINE | ID: mdl-34085500

RESUMEN

BACKGROUND: The esthetic outcome of a dental restoration largely depends on the translucency of the materials used, especially for monolithic restorations. Research has been published reporting a correlation between translucency and material thickness. However, no mathematical formula has been described yet. The aim of the present study was to determine the mathematical relationship between material thickness and translucency of three dental ceramic materials. MATERIAL AND METHODS: Three representative all-ceramic materials were taken out of the group of silicate ceramics (IPS Empress CAD LT), lithium X-silicate ceramics (IPS e.max CAD LT), and oxide ceramics (Lava Plus HT). Sixty specimens with five different thicknesses (0.4, 0.7, 1.0, 1.3, and 1.6 mm; N = 60, n = 12) were produced out of each ceramic (N = 180). A spectrophotometer was used to measure the transmittance coefficient tc[%] for each wavelength within the visible light spectrum, and the total light transmittance (T%) was calculated for each specimen. Linear, exponential, and logarithmic regression curves were fitted to the results. RESULTS: The logarithmic regression curves exhibited the best correlation (R2; IPS Empress CAD LT, R2 = 0.996; IPS e.max CAD LT, R2 = 0.987; Lava Plus HT, R2 = 0.907) to the transmittance values. CONCLUSION: Within the limitations of the present study, the transmittance behavior of silicate ceramics, lithium-X-silicate ceramics, and oxide ceramics can be described by a logarithmic equation. The findings of this study therefore suggest that the optical behavior might be calculable by a mathematical approach.


Asunto(s)
Porcelana Dental , Estética Dental , Cerámica , Diseño Asistido por Computadora , Humanos , Luz , Ensayo de Materiales , Espectrofotometría , Propiedades de Superficie
3.
J Adhes Dent ; 23(3): 255-265, 2021 Jun 05.
Artículo en Inglés | MEDLINE | ID: mdl-34060305

RESUMEN

PURPOSE: To evaluate the effect of different surface modification methods on the microtensile bond strength (µTBS) of four resin-matrix CAD/CAM ceramics after artificial aging. MATERIALS AND METHODS: Specimens of four CAD/CAM materials (Shofu Block HC, Lava Ultimate, Brilliant Crios, and Vita Enamic) were prepared and divided into four groups. Each group received one of the following treatments: group 1 (INT): no surface modification; group 2: sandblasting with 29-µm Al2O3 particles (SB); group 3: hydrofluoric acid etching (9%) + silane (HF+Si); group 4: sandblasting with 30-µm particles of the CoJet system (CJ). The specimens of each group were luted together in pairs using resin cement (RelyX Ultimate). After one week of water storage (37°C), the sandwich specimens were sectioned into rectangular microspecimens and half of them were immediately subjected to µTBS testing, while the other half was tested after six months. Data were statistically analyzed using FFANOVA including the factors of material, treatment, and storage time, with α = 0.05. RESULTS: After one week, the lowest µTBS was observed for INT, while the highest was found for either mechanical (SB and CJ) or chemical (HF+Si) treatments (p < 0.05). After six months, a significant decrease in µTBS was observed depending on treatment (p < 0.05), while artificial aging significantly influenced the µTBS of all experimental groups (p < 0.05). During the two storage periods, the failure type was mainly interfacial and was associated with the type of surface modification. CONCLUSION: After artificial aging, the µTBS appeared to depend on srface modification, while the parameter "material" did not influence the results. Consequently, adhesive strategies should be oriented towards surface modification techniques.


Asunto(s)
Recubrimiento Dental Adhesivo , Cementos de Resina , Cerámica , Ensayo de Materiales , Propiedades de Superficie , Resistencia a la Tracción
4.
Chemosphere ; 279: 130603, 2021 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-34134412

RESUMEN

Achieving adequate manganese removal during water treatment is a challenging process. This study aimed to assess the effectiveness of gravity driven ceramic membrane (GDCM) filtration in the elimination of manganese from surface water. The impact of membrane pre-modification with birnessite and molecular weight cut-off on long-term water treatment efficiency was investigated by assessing filtration units with 300 kDa virgin membrane (300 kDa-blank), 300 kDa membrane pre-coated with manganese oxides (300 kDa-MnOx), and 15 kDa virgin membrane (15 kDa-blank). The results of 300 kDa-blank and 300 kDa-MnOx indicated that depositing manganese oxides (produced via ozone (O3) oxidation) prior to water treatment was conducive to ripening of cake layer which played a major role in Mn removal. Reducing membrane molecular cut-off from 300 to 15 kDa also significantly reduced permeate Mn concentration, achieving a removal efficiency of 75% at the end of the trial (highest of all the units). Relative to 300 kDa-blank, the greater manganese removals in the other two systems can be attributed to 1) the long hydraulic retention times resulting from the higher membrane resistance, and 2) the higher abundance of biologically produced Birnessite materials in the cake layers for manganese oxidation. Raman analysis and X-ray diffraction analysis showed that 15 kDa-blank achieved the highest level of Birnessite production and most cake materials featured a flower-like structure and relatively small size (as shown under a scanning electron microscope and Energy Dispersive X-Ray Spectroscopy element mapping analysis), suggesting a higher surface area for Mn oxidation.


Asunto(s)
Ozono , Purificación del Agua , Cerámica , Filtración , Manganeso , Compuestos de Manganeso , Oxidación-Reducción , Óxidos , Agua
5.
Int J Mol Sci ; 22(11)2021 May 22.
Artículo en Inglés | MEDLINE | ID: mdl-34067261

RESUMEN

The present in vivo study determined the microbiological counts of the gingival crevicular fluid (GCF) among patients with fixed dental prostheses fabricated using three different techniques. A total of 129 subjects were divided into three study groups: first, cobalt-chrome-based, metal-ceramic prostheses fabricated by the conventional method (MC, n = 35); the second group consisted of cobalt-chrome-based, metal-ceramic prostheses fabricated by the computer-aided design and computer-aided manufacturing (CAD/CAM) technique (CC-MC, n = 35); the third group comprised zirconia-based ceramic prostheses fabricated using the CAD/CAM technique (CC-Zr, n = 35). The control consisted of 24 patients using prostheses fabricated with either MC, CC-MC, or CC-Zr. The GCF was obtained from the subjects before treatment, and 6 and 12 months after the prosthetic treatment. Bacteriological and bacterioscopic analysis of the GCF was performed to analyze the patients' GCF. The data were analyzed using SPSS V20 (IBM Company, Chicago, IL, USA). The number of microorganisms of the gingival crevicular fluid in all groups at 12 months of prosthetic treatment reduced dramatically compared with the data obtained before prosthetic treatment. Inflammatory processes in the periodontium occurred slowly in the case of zirconium oxide-based ceramic constructions due to their biocompatibility with the mucous membranes and tissues of the oral cavity as well as a reduced risk of dental biofilm formation. This should be considered by dentists and prosthodontists when choosing restoration materials for subjects with periodontal pathology.


Asunto(s)
Prótesis Dental/microbiología , Líquido del Surco Gingival/microbiología , Diente/microbiología , Adolescente , Adulto , Biopelículas/efectos de los fármacos , Cerámica/uso terapéutico , Diseño Asistido por Computadora , Femenino , Humanos , Masculino , Persona de Mediana Edad , Periodoncio/microbiología , Adulto Joven , Circonio/uso terapéutico
6.
Artículo en Chino | MEDLINE | ID: mdl-34074092

RESUMEN

Refractory ceramic fibers (RCFs) , as the main substitute for asbestos, are widely used because of their high temperature resistance and good thermal insulation. In the air of its production and use places, RCFs are inhalable fibers that are easy to deposit in the lungs. The results of a number of epidemiological studies and a variety of toxicological methods have shown that RCFs are related to the occurrence of lung diseases. This article reviews the four aspects of RCFs-induced pleural thickening, pulmonary fibrosis, lung function damage, tumor and genetic damage, and looks forward to the prospects of RCFs on respiratory system damage related research.


Asunto(s)
Asbestos , Enfermedades Pleurales , Fibrosis Pulmonar , Cerámica , Humanos , Pulmón , Fibras Minerales/toxicidad
7.
Wiad Lek ; 74(5): 1164-1168, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34090284

RESUMEN

OBJECTIVE: The aim: Determination of the factors complications occurrence in prosthetics with metal-ceramic prostheses. PATIENTS AND METHODS: Materials andmethods: Clinical, cytological, cytochemical methods and methods of statistical processing of the received data are applied. RESULTS: Results: A number of factors with different degrees of significance have been identified, which in the dynamics of clinical observations of the percentage of absorbed dispersion are decisive in the development of changes in the gums. At the stage of odontopreparation - the 1 factor, with the percentage of absorbed dispersion (12,3%) - preparation. The 2 factor - (11,9%) - traumatic. The 3 factor, periodontal, was slightly less significant (9,8%). In the dynamics of clinical observations for 45 days in the first place was the dissecting factor - (14%). The second most important factor was the vitality of the teeth - (11,5%). The 3 factor remained relatively stable - periodontal (8,5%). In the dynamics of clinical observations after 1 year, a redistribution of significance was noted. The largest percentage of absorbed dispersion covered periodontal factor - (15%). Vitality factor - (11%). Slightly lower, but clinically significant, of (8%) absorbed dispersion, was the preparation factor. CONCLUSION: Conclusions: Statistical analysis of the studied parameters made it possible to determine the key factors for predicting their development and diagnostics, it is important for organizing an increase in the effectiveness of orthopedic prophylactic therapeutic measures at the stages of restoration of dental hard tissues.


Asunto(s)
Miembros Artificiales , Dentadura Parcial Fija , Cerámica , Diseño de Dentadura , Implantación de Prótesis
8.
Shanghai Kou Qiang Yi Xue ; 30(2): 191-195, 2021 Apr.
Artículo en Chino | MEDLINE | ID: mdl-34109361

RESUMEN

PURPOSE: To investigate the clinical performance of chairside monolithic lithium disilicate glass-ceramics computer-aided design(CAD)-computer aided manufacturing(CAM) crowns, and to analyze the influencing factors of cumulative survival rate. METHODS: Two hundred and fourteen patients who had chairside posterior lithium disilicate glass-ceramic CAD-CAM crowns in Peking University Shenzhen Hospital from March 2015 to March 2017 were enrolled. The crown preparations were milled using Cerec Omnicam system. The clinical and esthetic effects of the crowns were analyzed at 3, 6, 12, 24, and 36 months. The cumulative survival rate of crowns was calculated, and the effects of gender, age, pulp condition, tooth position and adhesive type on the cumulative survival rate were analyzed. SPSS 20.0 software package was used for statistical analysis. RESULTS: After a 36-month follow-up, the failed crowns were mainly caused by marginal integrity, crown fracture and loss of retention. During the observation period of 3, 6, 12, 24 and 36 months, the scores of color, shape, quality of proximal contact, and chewing ability were greater than 9. The cumulative survival rates were 100.00%, 96.17%, 94.89%, 92.77% and 91.06% at 3, 6, 12, 24 and 36 months, respectively. The cumulative survival rate had no significant difference among different gender, age, and dental pulp status(P>0.05). CONCLUSIONS: Chairside monolithic lithium disilicate glass-ceramic CAD-CAM crowns have a high 3-year cumulative survival rate and good esthetic outcome, which is not affected by gender, age, and pulp status with high clinical value.


Asunto(s)
Diseño de Prótesis Dental , Estética Dental , Cerámica , Diseño Asistido por Computadora , Coronas , Porcelana Dental , Humanos , Ensayo de Materiales
9.
Hua Xi Kou Qiang Yi Xue Za Zhi ; 39(3): 336-340, 2021 Jun 01.
Artículo en Inglés, Chino | MEDLINE | ID: mdl-34041884

RESUMEN

OBJECTIVES: This study aimed to evaluate the color stability of tetracycline teeth restored with ceramic veneers of different thicknesses combined with different resin cement systems after aging. METHODS: Twenty patients with tetracycline teeth, including two maxillary central incisors, were selected clinically. The patients were randomly divided into four groups and restored with 0.5 and 0.75 mm ceramic veneers by using a veneer adhesive system, either with light-cured or dual-cured reaction. The color difference (ΔE) values after cementation and 1, 6, 12, and 24 months of use were obtained by quantification of L*, a*, and b* values with a colorimeter. The results were analyzed statistically with two-way ANOVA and Student's t test. RESULTS: The ΔE values of ceramic veneers detected after aging were less than 2.25. The 0.5 mm groups exhibited greater color change than the 0.75 mm-thick veneers (P<0.05). No significant difference was found on the color change of dual- or light-cured resin cements. CONCLUSIONS: Resin cements and veneer thickness influence the color of ceramic veneers after aging. Cementation of veneers with either dual- or light-cured resin cements does not affect the long-term color stability of tetracycline teeth differently.


Asunto(s)
Cerámica , Coronas con Frente Estético , Color , Porcelana Dental , Humanos , Ensayo de Materiales , Cementos de Resina , Tetraciclinas
10.
Hua Xi Kou Qiang Yi Xue Za Zhi ; 39(3): 341-346, 2021 Jun 01.
Artículo en Inglés, Chino | MEDLINE | ID: mdl-34041885

RESUMEN

OBJECTIVES: To analyze the chromatic properties and translucency of porcelain veneers made from different ceramic materials against the background of tetracycline-stained teeth. METHODS: Porcelain specimens (A1, A3, B2, B4) measuring 0.50 mm in thickness were prepared by heat-press casting and layering. The L*, a*, and b* values of the specimens against simulated tetracycline tooth and black-and-white backgrounds were measured by a spectrophotometer, and color differences ΔE001 between specimens on simulated tetracycline backgrounds and the backgrounds themselves and ΔE002 between specimens on simulated tetracycline backgrounds and the white background were calculated. The translucent parameter (TP) was also evaluated. RESULTS: The ΔE001 of feldspathic specimens (IPS d.SIGN) with the opaque layer was significantly greater than that of glass ceramic specimens (IPS e.max Press LT), and the ΔE001 of group B4 was consistently greater than those of the other color groups (P<0.05). The ΔE002 values of all feldspathic specimens with the opaque layer were less than 1.25, and the ΔE002 values of the glass ceramic specimens were greater than 2.23. However, no significant difference was observed among the different color groups (P>0.05). The TP values of feldspathic specimens with the opaque layer were significantly lower than those of glass ceramic specimens(P<0.05), but no significant difference was observed among different color groups (P>0.05). CONCLUSIONS: When changing the color of tetracycline-stained teeth, 0.50 mm-thick IPS d.SIGN feldspathic veneers with an opaque layer provide better chromatic properties than IPS e.max Press LT glass ceramic veneers. However, the translucency of feldspathic veneers is generally poorer than that of glass ceramic veneers.


Asunto(s)
Porcelana Dental , Coronas con Frente Estético , Cerámica , Color , Ensayo de Materiales , Tetraciclinas
11.
Bone Joint J ; 103-B(6 Supple A): 94-101, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-34053284

RESUMEN

AIMS: The aims of this study were to evaluate wear on the surface of cobalt-chromium (CoCr) femoral components used in total knee arthroplasty (TKA) and compare the wear of these components with that of ceramic femoral components. METHODS: Optical profilometry was used to evaluate surface roughness and to examine the features created by the wear process in a knee wear simulator. We developed a method of measuring surface changes on five CoCr femoral components and quantifying the loss of material from the articular surface during the wear process. We also examined the articular surface of three ceramic femoral components from a previous test for evidence of surface damage, and compared it with that of CoCr components. RESULTS: We found that the surface roughness of CoCr components rapidly increased during the first 1,000 wear cycles, then reached a steady state, but material loss from the surface continued at a rate of 1,778,000 µm3 per million cycles as carbides were removed from its matrix. These carbides formed third-body wear particles, leading to the formation of new scratches even as older scratches were worn away. In contrast, no scratching, loss of material, or other surface damage, when evaluated with one nanometer resolution, was found on the surface of the ceramic components after a 15 M wear cycle test. CONCLUSION: This study showed wear and loss of CoCr material from scratching and microabrasive wear in TKA. The material loss from the surface continued in a linear relationship with increasing cycles. We also found the absence of scratching and roughening of ceramic femoral components in simulated wear, suggesting an advantage in wear rate and avoiding metal sensitivity. This may have implications in the management of persistent pain after TKA. Cite this article: Bone Joint J 2021;103-B(6 Supple A):94-101.


Asunto(s)
Artroplastia de Reemplazo de Rodilla/instrumentación , Cerámica/química , Cromo/química , Cobalto/química , Fémur/cirugía , Prótesis de la Rodilla , Falla de Prótesis , Humanos , Ensayo de Materiales , Diseño de Prótesis , Propiedades de Superficie
12.
Am J Dent ; 34(2): 91-96, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33940666

RESUMEN

PURPOSE: To evaluate and compare the flexural strength of three CAD-CAM glass-ceramic materials and to investigate the effect of various surface treatments on their flexural strength. METHODS: 120 rectangular specimens were fabricated from three different types of CAD-CAM ceramic blocks and were divided into three groups: zirconia-reinforced lithium silicate (Celtra Duo, Group 1), leucite-reinforced glass-ceramic (IPS Empress CAD, Group 2), and lithium disilicate ceramic (IPS e.max CAD, Group 3). Dimensions of the specimens were standardized to 14.5x12.5 mm and 1.5 mm thickness. Specimens in each group were randomized into four subgroups. The first subgroup (NS) did not undergo any surface treatment; the second subgroup (P) underwent polishing only; the third subgroup (G) underwent glazing only; and the fourth subgroup (PG) underwent both polishing and glazing surface treatments. Biaxial flexural strength (FS) testing was performed until fracture occurred; FS was calculated in MPa. All analyses were performed using SPSS version 24. RESULTS: Group NS2 showed the lowest FS (89.34 ± 25.30 MPa). Group PG3 showed a significantly higher FS (365.38 ± 52.52 MPa) than Group P3 (268.15 ± 48.34). There was a statistically significant difference among the material groups for each surface treatment: IPS e.max CAD showed the highest FS, which was significantly greater than that of both Celtra Duo and IPS Empress CAD. The combination of polishing and glazing surface treatment resulted in significantly higher flexural strength than polishing alone for all three materials tested. For each material, no significant difference was found between the following surface treatments: control and polishing-only surface treatments; glazing-alone and the combination of polishing and glazing surface treatments. For each surface treatment, Celtra Duo showed significantly lower flexural strength than IPS e.max CAD. However, it displayed higher flexural strength than IPS Empress CAD, although the difference was only significant for glazing and the combination of polishing and glazing. CLINICAL SIGNIFICANCE: This study provides the clinician with an estimate of the flexural strength of glass-ceramic materials and shows how various surface treatments affect their strength.


Asunto(s)
Cerámica , Resistencia Flexional , Diseño Asistido por Computadora , Ensayo de Materiales , Propiedades de Superficie
13.
J Prosthet Dent ; 125(5): 804.e1-804.e6, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33934821

RESUMEN

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).


Asunto(s)
Implantes Dentales , Adaptación Marginal Dental , Cerámica , Diseño Asistido por Computadora , Coronas , Porcelana Dental , Diseño de Prótesis Dental
14.
Niger J Clin Pract ; 24(5): 705-711, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-34018980

RESUMEN

Background: Using lasers for adhesive restoration removal can be practical and atraumatic. Aims: The purpose of this study was to investigate Er: YAG laser exposure on debonding the adhesive cementation between enamel and feldspar ceramic, lithium disilicate-reinforced and resin nano ceramic composite laminate restorations. Materials and Methods: Vita Cerec Blocs, IPS e.max Computer-aided design (CAD). Computer-aided design and manufacturing (CAD-CAM) in full and Lava Ultimate restorative materials were chosen. The 3 × 3 mm2 standardized, 0.5-mm and 1 mm thick specimens were cemented on an enamel surface. After thermocycling, each material group was randomly divided into laser treated and control (non-laser treated) groups. Shear bond strength test was done with a universal testing machine with crosshead speed 0.5 mm/min. Factorial ANOVA Technique and TUKEY HSD multiple comparison test were used for statistical analyses. Moreover, the surface morphology of the debonded samples and the enamel was observed using a scanning electron microscope. Results: The laser application was found to weaken the SBS values significantly (P < 0.05) for all groups; however, the most dramatic SBS decrease was observed for laser treated IPS e.max at both thicknesses. Conclusions: Laser treatment can serve as a practical and effective method that eliminates the risk the enamel damage and restoration fracture.


Asunto(s)
Cerámica , Diseño Asistido por Computadora , Resinas Compuestas , Humanos , Rayos Láser , Ensayo de Materiales , Propiedades de Superficie
15.
Int J Comput Dent ; 24(1): 41-51, 2021 Feb 26.
Artículo en Inglés | MEDLINE | ID: mdl-34006062

RESUMEN

AIM: To evaluate the fracture resistance and failure pattern of endodontically treated teeth with post and cores made of different CAD/CAM materials in comparison with cast post and cores. MATERIALS AND METHODS: A total of 40 maxillary central incisors were divided into four groups. Post and cores were fabricated using the following materials: fiber-reinforced composite, high-density polymer, polymer-infiltrated ceramic network, and nonprecious metal alloy as a control group. Specimens were covered with lithium disilicate crowns and subjected to thermomechanical cyclic loading followed by fracture resistance testing until failure. One-way ANOVA followed by Bonferroni multiple comparison tests were used to determine significant differences between the four groups. The significance level was set at 0.05. 3D finite element analysis was then performed, and results were analyzed based on the von Mises stress distribution criteria and the maximum principal stress for the possible failure areas. RESULTS: No statistically significant differences were found in the fracture resistance between the four groups. In terms of unrestorable failures, no significant differences were found among the tested groups. CONCLUSION: The tested post and cores have comparable fracture resistance to that of metallic cast post and cores in the anterior region. CLINICAL SIGNIFICANCE: Post and cores made of CAD/CAM materials offer an acceptable alternative for the restoration of anterior teeth.


Asunto(s)
Técnica de Perno Muñón , Diente no Vital , Cerámica , Diseño Asistido por Computadora , Coronas , Fracaso de la Restauración Dental , Análisis del Estrés Dental , Humanos , Incisivo , Ensayo de Materiales
16.
Int J Comput Dent ; 24(1): 77-88, 2021 Feb 26.
Artículo en Inglés | MEDLINE | ID: mdl-34006065

RESUMEN

For restoring extensive cavities in severely damaged or decayed posterior teeth, especially those with thin walls, indirect restorations are recommended rather than direct fillings. Regarding indirect restorations for inlays and onlays, composite resin-based CAD/CAM materials are considered to have several advantages over ceramics such as easy manufacturing, lower cost, and simpler repairability. A case is presented in this article in which the treatment plan and protocol combine multiple evidence-based clinical techniques such as immediate dentin sealing (IDS), cavity design optimization (CDO), and cervical margin relocation (CMR). For CDO and CMR, two different types of flowable composite resins with different viscosities were used. Restoring such extensively damaged teeth using a defect-oriented adhesive technique is considered a challenge both in terms of the preservation of healthy tooth structure and the proper isolation for adhesive luting. The IDS technique was used to enhance the bonding to the remaining dentin, while CDO was performed to avoid unnecessary removal of vital tooth structure, for example, undercuts. The deep subgingival margins were elevated using the CMR technique to facilitate the impression taking and a contamination-free luting of the final restoration. Combining the aforementioned techniques enabled a defect-oriented, minimally invasive restoration of a severely decayed tooth. The aim of this article is to present those techniques in a simplified way through a clinical case as a step-by-step guide for the practitioner.


Asunto(s)
Recubrimiento Dental Adhesivo , Incrustaciones , Cerámica , Resinas Compuestas , Diseño Asistido por Computadora , Humanos , Cementos de Resina
17.
J Environ Manage ; 291: 112681, 2021 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-33965703

RESUMEN

Maintenance of existing household arsenic (As) removal technologies are comparatively difficult due to the use of the sand beds as a filter. Moreover, pre-aeration of groundwater is avoided during filter operation that may affect the removal efficiency. This study investigated the effect of pre-aeration on the efficacy of simple iron nested ceramic filter (CF) for the removal of As and Fe from the natural groundwater. Five CFs at 5 households in the Bagerhat district of Bangladesh were tested for 31 days with pre-aerated groundwater (AGW system) and non-aerated groundwater (NAGW system). Pe-aeration of groundwater significantly improved (p > 0.5) the removal efficiency of As and Fe in the CFs. The filters effectively removed As in the groundwater from 203 - 231 µg/L to 29-40 µg/L in the AGW system whereas the effluent As were >50 µg/L in the NAGW system. Iron (Fe) was also removed effectively and the overall As and Fe removal efficiency were more than 82% and 99%, respectively in the AGW system. Removal of Mn and PO4-P were significantly enhanced achieving more than 56% and 99% removal, respectively in the AGW system. X-ray absorption fine structure (XAFS) analysis indicated that the oxidation of Fe2+ and As(III) and subsequent adoption/precipitation are the main processes controlling the removals of As and Fe in the CFs. Two stages oxidation of Fe2+ and As(III) in the AGW system facilitated to increase As and Fe removal efficiency. The findings of this study suggest that the iron net nested ceramic filters with pre-aeration step is an effective method and can be employed at the household level in As contaminated region.


Asunto(s)
Arsénico , Agua Subterránea , Contaminantes Químicos del Agua , Purificación del Agua , Arsénico/análisis , Bangladesh , Cerámica , Filtración , Hierro/análisis , Contaminantes Químicos del Agua/análisis
18.
Mater Sci Eng C Mater Biol Appl ; 124: 112060, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33947554

RESUMEN

This work reports a new CaO-MgO-SiO2 (CMS) bioactive glass-ceramic, using ZrO2 as a nucleus to modulate the ratios of glass and ceramic phases as a function of sintering temperature. Mg-rich bioactive CMS glass-ceramics exhibit advantages regarding mechanical strength (flexural strength ~190 MPa and compressive strength ~555 MPa), in-vitro and in-vivo biocompatibilities, and bone ingrowth. The high mechanical strengths could be attributed to the CaMgSi2O6 glass-ceramic and lower porosity. X-ray absorption spectra indicate an increased SiO covalent bond via the development of CaMgSi2O6 glass-ceramics. From the in-vitro cytotoxicity and BMSC differentiation assays, the CMS samples sintered above 800 °C exhibited better cell attachment and differentiation, possibly due to structural stability, appropriate pore, and ion release to boost osteogenesis. Compared to hydroxyapatite (HA) ceramics, the CMS glass-ceramics display higher mechanical strengths, biocompatibility, and osteoconductivity. An in-vivo experiment demonstrated a fine bone-ingrowth profile around the CMS implant. This study may further the application of CMS glass-ceramics in bone implants.


Asunto(s)
Óxido de Magnesio , Dióxido de Silicio , Cerámica , Durapatita , Vidrio
19.
Compend Contin Educ Dent ; 42(4): 188-191, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33960804

RESUMEN

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.


Asunto(s)
Litio , Dique de Goma , Cerámica , Coronas , Esmalte Dental , Porcelana Dental , Humanos , Diente Molar , Cementos de Resina
20.
Int J Mol Sci ; 22(9)2021 Apr 29.
Artículo en Inglés | MEDLINE | ID: mdl-33946764

RESUMEN

Micro arc oxidation (MAO) is a prominent surface treatment to form bioceramic coating layers with beneficial physical, chemical, and biological properties on the metal substrates for biomaterial applications. In this study, MAO treatment has been performed to modify the surface characteristics of AZ31 Mg alloy to enhance the biocompatibility and corrosion resistance for implant applications by using an electrolytic mixture of Ca3(PO4)2 and C10H16N2O8 (EDTA) in the solutions. For this purpose, the calcium phosphate (Ca-P) containing thin film was successfully fabricated on the surface of the implant material. After in-vivo implantation into the rabbit bone for four weeks, the apparent growth of soft tissues and bone healing effects have been documented. The morphology, microstructure, chemical composition, and phase structures of the coating were identified by SEM, XPS, and XRD. The corrosion resistance of the coating was analyzed by polarization and salt spray test. The coatings consist of Ca-P compounds continuously have proliferation activity and show better corrosion resistance and lower roughness in comparison to mere MAO coated AZ31. The corrosion current density decreased to approximately 2.81 × 10-7 A/cm2 and roughness was reduced to 0.622 µm. Thus, based on the results, it was anticipated that the development of degradable materials and implants would be feasible using this method. This study aims to fabricate MAO coatings for orthopedic magnesium implants that can enhance bioactivity, biocompatibility, and prevent additional surgery and implant-related infections to be used in clinical applications.


Asunto(s)
Regeneración Ósea , Sustitutos de Huesos/química , Fosfatos de Calcio/química , Materiales Biocompatibles Revestidos/química , Aleaciones/química , Animales , Tornillos Óseos , Línea Celular , Cerámica , Corrosión , Fémur/diagnóstico por imagen , Fémur/cirugía , Ensayo de Materiales , Ratones , Microscopía Electrónica de Rastreo , Modelos Animales , Oxidación-Reducción , Espectroscopía de Fotoelectrones , Prótesis e Implantes , Conejos , Propiedades de Superficie , Difracción de Rayos X , Microtomografía por Rayos X
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