Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 81
Filtrar
1.
J Prosthet Dent ; 2021 Mar 18.
Artículo en Inglés | MEDLINE | ID: mdl-33745685

RESUMEN

STATEMENT OF PROBLEM: Although recent studies have reported the success of implant-supported monolithic restorations, consensus on the use of monolithic ceramic restorations is lacking. PURPOSE: The purpose of this systematic review and meta-analysis was to evaluate the survival and biological and technical complication rates of monolithic single crowns and fixed partial dentures (FPDs). MATERIAL AND METHODS: An electronic search was conducted by 2 independent authors on the PubMed/MEDLINE, Scopus, and Cochrane Library databases. The Newcastle-Ottawa scale and Cochrane risk of bias tool were used to assess the quality and risk of bias of the included studies. Meta-analysis was performed by using the R software program. RESULTS: The search identified 763 articles, 18 of which met the eligibility criteria. A total of 15 studies evaluated monolithic ceramic single crowns, and 4 studies evaluated FPDs. The studies included 1061 monolithic single crowns (524 lithium disilicate, 461 zirconia, and 76 polymer-infiltrated ceramic network [PICN]) and 104 FPDs (36 lithium disilicate and 68 zirconia). Meta-analysis of single-arm studies indicated the proportion of survival, biological, and technical complication rates of 1% (95% confidence interval [CI]: 0% to 3%), 1% (CI: 0% to 4%), and 2% (CI: 1% to 4%), respectively, for single crowns, independent of ceramic material, and 3% (CI: 0% to 34%), 5% (CI: 1% to 21%), and 5% (CI: 1% to 21%) for FPDs, respectively. Only 5 studies performed a direct comparison between monolithic and veneered ceramic restorations, and no significant difference was observed in terms of survival (risk ratio [RR]: 0.68; CI: 0.25-1.91; P=.96), biological (RR: 0.69; CI: 0.31-1.53; P=.35), and technical complication rates (RR: 0.87; CI: 0.40-1.88; P=.29). CONCLUSIONS: The use of monolithic ceramic can be considered a favorable treatment for tooth-supported single crowns and FPDs, with high survival and low complication rates. However, further randomized controlled trials are needed to reassess these clinical performances, mainly by comparing them with the performance of veneered restorations.

2.
J Esthet Restor Dent ; 2020 Oct 12.
Artículo en Inglés | MEDLINE | ID: mdl-33045124

RESUMEN

OBJECTIVE: To evaluate the optical, chemical, and mechanical properties of feldspathic porcelain after handling with different instrument materials. MATERIAL AND METHODS: Feldspathic porcelain was manipulated with different spatula compositions: metal spatula (MS), plastic spatula (PS), and glass spatula (GS) for the fabrication of 30 (n = 10) disks. Contrast ratio (CR), translucency parameter (TP), and surface Knoop microhardness (KHN) were measured. The color change (ΔE00 ) was evaluated using the CIEDE2000 system. Scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) were used for surface analysis. Data were analyzed using one-way ANOVA and Tukey test (P < 0.05). RESULTS: All groups presented different morphological surfaces with higher presence of Al on the MS. PS group presented lower Al, Si, K than MS, and GS. Higher CR was observed for PS (0.734; P < 0.043), followed by MS (0.696; P < 0.043) and GS (0.65; P < 0.011). The highest TP (13.06) and KHN (386.27) were presented by GS (P < 0.001). MS and PS presented similar KHN results. The higher ΔE00 were found for plastic/metal comparison. Also, the L* values for the MS group (67.49) were lower than the other groups. CONCLUSION: The use of metal spatula promoted higher color alteration during feldspathic porcelain manipulation than did the other materials. Handling with glass instrument promoted higher microhardness than other spatula materials. CLINICAL SIGNIFICANCE: The effect of the material used for ceramic handling on feldspathic porcelain properties is often ignored. This study shows that the handling spatula material must be carefully chosen to avoid inadvertent changes to the feldspathic porcelain restoration.

3.
Int J Dent ; 2020: 8492091, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32884572

RESUMEN

Objective: To evaluate the influence of different pigmentations and accelerated aging on the hardness and tear strength of the A-2186 and MDX4-4210 silicones. Materials and Methods: The samples A-2186 and MDX4-4210 were manufactured without and with pigmentations (black, bronze, and pink). For the Shore A hardness test, 80 samples of each silicone were fabricated, and for the tear strength test, 320 samples of each silicone were fabricated. Eight groups were created for each test (n = 10). These tests were performed before and after 252, 504, and 1008 hours of aging. Three-way repeated-measures analysis of variance and the Tukey test were performed (α = 0.05). Results: The A-2186 silicone showed higher hardness and tear strength when compared with the MDX4-4210 silicone (p < 0.05), except in the hardness of the A-2186 and MDX4-4210 groups without pigmentation after 1008 hours (p > 0.05). All hardness values were between 25 and 35 units, regardless of the silicone type, period, and pigmentation (or no pigmentation). In most situations, the hardness of silicones used increased after 252 hours (p < 0.05). The nonpigmented MDX4-4210 group and all A-2186 groups showed an increase in tear strength after 252 hours (p < 0.05). For the nonpigmented MDX4-4210 group, from 252 to 1008 hours, there was no change in tear strength (p > 0.05). All pigmented MDX4-4210 groups showed no change in tear strength from 0 (initial) to 1008 hours of aging (p > 0.05). In all A-2186 groups, from 252 to 504 hours, there was a reduction in tear strength (p < 0.05), and from 504 to 1008 hours, there was an increase in tear strength (p < 0.05), except in the bronze A-2186 group (p > 0.05). Conclusion: In most situations, the A-2186 silicone showed significantly higher values of hardness and tear strength than the MDX4-4210 silicone. All hardness values were considered clinically acceptable. Accelerated aging could increase, decrease, or not significantly change the hardness and tear strength of the silicones used. The results of hardness and tear strength suggest that MDX4-4210 was more influenced by the presence of pigmentation after aging.

4.
J Clin Exp Dent ; 12(2): e103-e107, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-32071690

RESUMEN

Background: Different ceramic surface cleaning methods have been suggested after the acid conditioning. The aim was to evaluate the effect of different protocols used to remove the remaining hydrofluoric acid on the shear bond strength (SBS) between lithium disilicate and resin cement. Material and Methods: Forty-four specimens of lithium disilicate (IPS e.max Press) were divided in 4 groups (n=11): group C (control, no treatment); group HF+S (5% hydrofluoric acid + silane); group HF+US+S (5% hydrofluoric acid + ultrasound cleaning + silane); group HF+PH+S (5% hydrofluoric acid + 37% phosphoric acid + silane). Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were performed to characterize the surface morphology. The SBS test was performed on the resin/ceramic interface, and the failure mode was characterized. SBS values were submitted to 1-way ANOVA and the Tukey test (α=.05). The relation between surface treatment and failure modes was analyzed using the chi-squared test (α=.05). Results: The surface treatment type interfered in the shear strength (p<.001) and higher SBS values were observed for the groups HF+US+S (17.87 MPa) and HF+PH+S (16.37 MPa). The surface treatment did not influence the failure mode (p=.713). No fluorsilicate salts were observed after ultrasound cleaning. Conclusions: The utilization of ultrasound cleaning was an effective procedure to remove remaining fluorsilicate salts, promoting the highest SBS values. Key words:Bond strength, ceramics, fluorsilicate, lithium disilicate, resin cement.

5.
Arch Oral Biol ; 111: 104643, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-31918345

RESUMEN

AIM: To evaluate the cytotoxicity and inflammatory response of different types of provisional restorative materials to mice gingival fibroblasts. METHODS: Cytotoxicity of provisional material discs (thermal-polymerized acrylic resin; auto-polymerized acrylic resin; bisacrylic resin; nano-ceramic resin for CAD/CAM and prefabricated polymer block for CAD/CAM) to Mice (Balb/c) gingival cell were investigated under direct and indirect contact (extracts) at 24, 48 and 72 h, using the MTT and Alamar blue assays. Materials extracts (24 h) were applied to the cell culture (indirect contact) or cells were seeded on discs of provisional materials, and the cytotoxicity and production of IL-6, IL-1ß and TNF-α after 24, 48 and 72 h were analyzed through MTT, Alamar Blue® and ELISA. Culture medium was used as control for indirect contact assay (extract) and the surfaces of the wells without discs of provisional materials were used as control for direct contact assay. Results were analysed statistically by ANOVA followed by the Bonferroni-Test correction. Statistically significant differences were considered if P was < .05. RESULTS: Auto-polymerized and bisacrylic resins (direct contact) reduced cell viability after 24, 48 and 72 h compared to control (P < .05). Indirect contact (extract) was not cytotoxic to cells at all periods compared to control (P > .05). Auto-polymerized and bisacrylic resins increased IL-6, IL-1ß and TNF-α levels mainly at 24 h when compared to the other materials (P < .001). CONCLUSION: Auto-polymerized and bisacrylic were more cytotoxic to mice gingival fibroblasts. CAD/CAM nano ceramic resin and prefabricated polymer blocks are more predictable materials to preserve the periodontal soft tissues.


Asunto(s)
Resinas Acrílicas , Materiales Dentales , Animales , Cerámica , Resinas Compuestas , Diseño Asistido por Computadora , Ensayo de Materiales , Ratones , Propiedades de Superficie
6.
J Clin Exp Dent ; 11(9): e807-e813, 2019 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-31636873

RESUMEN

Background: The aim of this study was to evaluate the distribution of stress in complete fixed mandibular prostheses with infrastructures (IE) fabricated with different materials and techniques, under compressive force. Material and Methods: A model of an edentulous mandible, which received five 4x11 mm external hexagon implants between the mental foramens, was fabricated. The groups were divided into: Group I - IE in nickel-chromium with an acrylic resin occlusal coating; Group II - IE in nickel-chromium with a ceramic occlusal coating; Group III - IE milled in zirconia with a ceramic coating. For the photoelastic methodology, 70 N axial loads were applied in three regions. Photographic images were taken and analyzed according to the number of high-intensity fringes. For the strain gauge methodology, the measurement of stresses was performed in two distinct regions. The same compression tests described earlier were then performed. The registered stress values were grouped in tables and submitted to two-factor variance analysis (ANOVA) and the Tukey test with 5% significance. Results: The results of the two methodologies demonstrated smaller stress values for Group I, when compared to the other groups. Conclusions: It was possible to conclude that the complete fixed prostheses, with infrastructures cast in metal and acrylic occlusal coating, demonstrated better biomechanical results. Key words:Dental implants, mandibular prosthesis implantation, biomechanics.

7.
Arch. Health Invest ; 8(1): 6-12, jan. 2019. ilus
Artículo en Portugués | BBO - Odontología | ID: biblio-994966

RESUMEN

Para alcançar a estética em dentes anteriores deve-se ter conhecimento de diversas técnicas e principalmente fazer a escolha correta dos materiais. As cerâmicas odontológicas estão cada vez mais presentes nas restaurações, visto que possuem ótimas propriedades ópticas e mecânicas. Assim, o objetivo deste estudo foi proporcionar a estética em dentes anteriores com diferentes subtratos através de uma prótese fixa metal-free. Paciente do gênero masculino, 38 anos, procurou atendimento queixando-se da estética do seu sorriso. No exame clínico foi observada uma coroa total metalocerâmica no elemento 21 e facetas de resina composta nos elementos 11,12 e 22, todas com estética insatisfatória. O dente 21 apresentava um núcleo metálico fundido adequado e os dentes 12 e 22 com tratamentos endodônticos. Foi proposta a instalação de pinos de fibra de vidro nos dentes 12 e 22. Além, da confecção de coroas totais metais-free em dissilicato de lítio nos quatro incisivos superiores com o sistema e-max ceram. O resultado final estético e funcional foi aprovado pelo paciente e pelos profissionais envolvidos(AU)


To achieve aesthetics in anterior teeth one must be aware of several techniques and especially make the correct choice of materials. Dental ceramics are increasingly present in restorations, since they have excellent optical and mechanical properties. Thus, the objective of this study was to achieve esthetics in anterior teeth with different substrate through a fixed prosthesis metal-free. A male patient, 38 years old, sought care complaining about the aesthetics of his smile. In the clinical examination a total metaloceramic crown was observed in element 21 and composite resin facets in elements 11,12 and 22, all with unsatisfactory aesthetics. Tooth 21 had a suitable molten metal core and teeth 12 and 22 with endodontic treatments. It was proposed to install fiberglass pins on the teeth 12 and 22. In addition, from the manufacture of total metal-free crowns in lithium disilicate in the four upper incisors with the e-max system ceram. The final aesthetic and functional result was approved by the patient and the professionals involved(AU)


Para alcanzar la estética en dientes anteriores se debe tener conocimiento de diversas técnicas y principalmente hacer la elección correcta de los materiales. Las cerámicas dentales están cada vez más presentes en las restauraciones, ya que poseen óptimas propiedades ópticas y mecánicas. Así, el objetivo de este estudio fue proporcionar la estética en dientes anteriores con diferentes sustratos a través de una prótesis fija metal-free. Paciente del género masculino, 38 años, buscó atención quejándose de la estética de su sonrisa. En el examen clínico se observó una corona total metalocerámica en el elemento 21 y facetas de resina compuesta en los elementos 11,12 y 22, todas con estética insatisfactoria. El diente 21 presentaba un núcleo metálico fundido adecuado y los dientes 12 y 22 con tratamientos endodónticos. Se propuso la instalación de pines de fibra de vidrio en los dientes 12 y 22. Además, de la confección de coronas totales metales libres en disilicato de litio en los cuatro incisivos superiores con el sistema e-max ceram. El resultado final estético y funcional fue aprobado por el paciente y los profesionales involucrados(AU)


Asunto(s)
Humanos , Masculino , Adulto , Cerámica , Prótesis Dental de Soporte Implantado , Rehabilitación Bucal , Sonrisa , Estética Dental
8.
Arch. Health Invest ; 8(1): 13-19, jan. 2019. ilus
Artículo en Portugués | BBO - Odontología | ID: biblio-994969

RESUMEN

Devido a evolução dos sistemas cerâmicos, atualmente, são permitidas inúmeras associações de materiais restauradores. Entretanto, mimetizar as características visuais das próteses livres de metal com próteses metalocerâmica permanece um desafio. Assim, o objetivo deste trabalho foi relatar o caso clínico de substituição de próteses desadaptadas, homogeneizando próteses parciais fixas livres de metal e metalocerâmicas dento e implantossuportadas, após cirurgia periodontal. O paciente de 55 anos, gênero masculino, compareceu à Clínica de Prótese Parcial Fixa, da Faculdade de Odontologia de Araçatuba ­ FOA/UNESP em 2017 queixando-se dos seus dentes anteriores estarem "feios" e com a "raiz aparecendo". No exame clínico foi constatada recessão gengival nos elementos 11 e 13, os quais continham uma prótese parcial fixa de três elementos metalocerâmicas desadaptada, prótese sobre implante nos elementos 21 e 22, que apresentavam-se desadaptadas e com estética desfavorável. No exame radiográfico pôde-se observar a presença de um núcleo metálico fundido nos elementos 11 e 13. Foi proposto, então, a confecção de coroas totais livres de metal nos elementos anteriores superiores (13, 12, 11, 21 e 23) e coroa metalocerâmica para o elemento 22. Para isso, foi realizado enceramento diagnóstico inicial e, após o consentimento do paciente, foi efetuada a remoção das próteses antigas. Com a remoção, visualizamos uma . depressão na vestibular do rebordo na área do 12 (ausente), solucionado com um enxerto gengival subepitelialApós a realização dos preparos dentários e moldagem com silicone de adição as peças foram confeccionadas com sistema e.max Ceram (Ivoclar Vivadent). Após a prova estética e ajustes oclusais iniciais, as peças foram preparadas para cimentação resinosa com o sistema Variolink® N (Ivoclar Vivadent). O cimento transparente Conclui-se que, apesar da disparidade dos materiais, é possível mimetizá-los e foi selecionado previamente por meio de provas com o kit Try-In.oferecer resultados reabilitadores suficientemente estéticos e satisfatórios(AU)


Due to the evolution of ceramic systems, numerous associations of restorative materials are now permitted. However, mimicking the visual characteristics of metal-free prostheses with metal-ceramic dentures remains a challenge. Thus, the objective of this study was to report the clinical case of replacement of maladaptive dentures, homogenizing denture free and fixed metal partial dentures and implants supported after periodontal surgery. The patient, 55 years old, male, attended the Fixed Partial Prosthesis Clinic of the Faculty of Dentistry of Araçatuba - FOA / UNESP in 2017 complaining that his anterior teeth were "ugly" and with the "root appearing". In the clinical examination, gingival recession was observed in elements 11 and 13, which contained a fixed partial prosthesis of three maladaptive metal-ceramic elements, a prosthesis on implants in elements 21 and 22, the prostheses were maladapted and unfavorable esthetics. In the radiographic examination it is possible to observe the presence of a molten metal nucleus in elements 11 and 13. It was proposed, then, the manufacture of free metal crowns in the upper anterior elements (13, 12, 11, 21 and 23) and crown PFM for the element 22. For this, it performed waxing initial diagnosis and after the patient's consent, the removal of the old prosthesis were performed. Upon removal, a depression visualize the buccal flange in the area 12 (absent), solved with a subepithelial gum graft. After the dental preparations and molding with silicone of addition the pieces were made with e.max Ceram system (Ivoclar Vivadent). After the initial test and aesthetic occlusal adjustments, the pieces were prepared for cementing with resin Variolink® N system (Ivoclar Vivadent). The clear cement was previously selected by the test realized with Try-In kit. We conclude that, despite the disparity of materials, it is possible to mimic them and offer rehabilitative results sufficiently aesthetic and satisfactory(AU)


Debido a la evolución de los sistemas cerámicos, actualmente, se permiten numerosas asociaciones de materiales restauradores. Sin embargo, mimetizar las características visuales de las prótesis libres de metal con prótesis metalocerámicas sigue siendo un desafío. Así, el objetivo de este trabajo fue relatar el caso clínico de sustitución de prótesis desadaptadas, homogeneizando prótesis parciales fijas libres de metal y metalocerámicas dento e implantosuportadas, después de cirugía periodontal. El paciente de 55 años, género masculino, asistió a la Clínica de Prótesis Parcial Fija, de la Facultad de Odontología de Araçatuba - FOA / UNESP en 2017 quejándose de sus dientes anteriores estar "feos" y con la "raíz apareciendo". En el examen clínico se constató recesión gingival en los elementos 11 y 13, los cuales contenían una prótesis parcial fija de tres elementos metalocerámicos desadaptados, prótesis sobre implante en los elementos 21 y 22, las prótesis se presentaban desadaptadas y con estética desfavorable. En el examen radiográfico se puede observar la presencia de un núcleo metálico fundido en los elementos 11 y 13. Se propuso entonces la confección de coronas totales de metal en los elementos anteriores superiores (13, 12, 11, 21 y 23) y corona metalocerámica para el elemento 22. Para ello, se realizó el encerado diagnóstico inicial y, tras el consentimiento del paciente, se efectuó la remoción de las prótesis antiguas. Con la remoción, visualizamos una depresión en la vestibular del borde en el área del 12 (ausente), solucionado con un injerto gingival subepitelial. Después de la realización de los preparados dentales y moldeo con silicona de adición las piezas fueron confeccionadas con sistema e.max Ceram (Ivoclar Vivadent). Después de la prueba estética y ajustes oclusales iniciales, las piezas fueron preparadas para cementación resinosa con el sistema Variolink® N (Ivoclar Vivadent). El cemento transparente fue seleccionado previamente por medio de pruebas con el kit Try-In. Se concluye que, a pesar de la disparidad de los materiales, es posible mimetizarlos y ofrecer resultados rehabilitadores suficientemente estéticos y satisfactorios(AU)


Asunto(s)
Humanos , Masculino , Persona de Mediana Edad , Cerámica , Prótesis Dental de Soporte Implantado , Dentadura Parcial Fija , Implantes Dentales , Estética Dental , Rehabilitación Bucal
9.
J Med Eng Technol ; 42(5): 359-367, 2018 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-30251571

RESUMEN

In some clinical situations, the clinician may encounter previously installed implants that should be associated with other implants for a proper rehabilitation. The aim of this study was to evaluate the biomechanical behaviour of a multiple prosthesis joined by different implant connections using photoelasticity. Photoelastic models with a screwed fixed prosthesis supported by implants with different connection systems (Morse taper, external hexagon, internal hexagon, and Flexcone), and different combinations among them, were fabricated. Each assembly was placed in a circular polariscope, and axial and oblique (45°) loads of 100 N were applied on the occlusal surface of the crowns. The fringe patterns were photographed and the analysis was performed by counting the number of high-intensity fringes and also according to the stress distribution region where they appeared. Among implants of the same connection, the external connections obtained a greater number of high intensity fringes when compared to the internal connections. From the biomechanical point of view, the association between different types of connections obtained positive results.


Asunto(s)
Prótesis e Implantes , Fenómenos Biomecánicos , Estrés Mecánico
10.
J Prosthodont ; 27(7): 624-635, 2018 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-29235205

RESUMEN

PURPOSE: The objective of this systematic review with meta-analysis was to evaluate surface treatment in yttria-stabilized tetragonal zirconia polycrystal ceramic (Y-TZP) on the shear bond strength (SBS) values between Y-TZP (core ceramic) and veneer ceramic, compared to untreated specimens. MATERIALS AND METHODS: This review was registered at PROSPERO platform under the number CRD42016036493. The systematic review of the extracted publications was performed to compare the effect of surface treatment on SBS between Y-TZP ceramic and veneering ceramic. A comprehensive review of the literature from the earliest available dates through January 2017 was performed in the PubMed/Medline, Embase, Scopus, and Cochrane Library databases. RESULTS: A total of 15 studies were identified for the inclusion of data, with only in vitro studies. A random-effect model found statistically significant differences between untreated and treated surfaces of Y-TZP (p < 0.00001; MD: 2.84; 95% CI: 2.19 to 3.49). In another analysis, a random-effect model found statistically significant differences between the groups that only performed the associations of treatments and control group (p < 0.00001; MD: 3.19; 95% CI: 2.11 to 4.28). CONCLUSIONS: Surface treatment in Y-TZP improved the values of SBS between the Y-TZP and veneer ceramic. The associations between two or more treatments also showed positive effect on the bond strength due the cumulative effect of the treatments.


Asunto(s)
Cerámica/química , Recubrimiento Dental Adhesivo/métodos , Coronas con Frente Estético , Itrio/química , Circonio/química , Humanos , Ensayo de Materiales , Resistencia al Corte , Propiedades de Superficie
11.
Braz. j. oral sci ; 17: e18027, 2018. tab
Artículo en Inglés | LILACS, BBO - Odontología | ID: biblio-963756

RESUMEN

Evaluate the color stability of facial silicone pigmented extrinsically under the influence of the hygiene process. Methods: 160 samples were prepared and divided into 8 groups (n = 20) according to the pigmentation technique used: Group 1: Colorless silicone; Group 2: Pigmented exclusively with oil ink; Group 3: Pigmented with oil ink + opacifier; Group 4: Colorless, applying Prime; Group 5: Pigmented with oil ink covered with Prime; Group 6: Pigmented with oil ink + opacifier and covered with Prime; Group 7: Pigmented with oil ink diluted in Prime; Group 8: Pigmented with oil ink + opacifier diluted in Prime. Then the samples were distributed into two subgropus (n=10): 1: neutral soap and 2: 1% hypochlorite solution. The color readings occurred in the initial period and 60 days after the hygiene procedures. For this, it was used a spectrophotometer reflection and CIE-Lab program. The data was tabulated and submitted to analysis of variance (ANOVA) followed by Tukey test (p <0.05). Results: The groups of samples disinfected with soap showed significantly lower color change values than those presented by the samples disinfected with hypochlorite. The best results were presented by the group of samples pigmented with oil ink diluted in prime and sanitized with neutral soap (ΔE=1.21, without opacifier and ΔE=0.82, with opacifier). Conclusions: The association of oil ink diluted in prime and hygiene technique with soap promotes the lower color change of facial silicone pigmented extrinsically


Asunto(s)
Siliconas , Desinfección , Coloración de Prótesis , Prótesis Maxilofacial , Color
12.
Implant Dent ; 26(1): 106-111, 2017 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-28060024

RESUMEN

PURPOSE: The aim of this study was to assess stress distribution in the bone-implant interface of a mandibular implant-supported prosthesis with different cantilever lengths, aesthetic coating materials, and implant abutments. MATERIALS AND METHODS: A photoelastic model of an edentulous mandible, containing 5 external hexagon implants, was constructed. Experimental models were divided into 6 groups: group 1-UCLA component and metal bar; group 2-UCLA component and acrylic resin coating; group 3-UCLA component and porcelain coating; group 4-abutment and metal bar; group 5-abutment and acrylic resin coating; and group 6-abutment and porcelain coating. Forces were applied to the most anterior implant, the most posterior implant, and different cantilever lengths. RESULTS: The results showed a higher number of high-stress fringes as the cantilever length increased. Fringes were better distributed in groups with prostheses composed of acrylic resin and in groups that contained an abutment. CONCLUSION: The stress distribution in the bone-implant interface is improved when the cantilever is eliminated and when abutments in an acrylic resin prosthesis are used.


Asunto(s)
Prótesis Dental de Soporte Implantado/métodos , Dentadura Completa , Interfase Hueso-Implante/fisiopatología , Retención de Prótesis Dentales , Prótesis Dental de Soporte Implantado/normas , Análisis del Estrés Dental , Dentadura Completa/normas , Humanos , Técnicas In Vitro , Resinas Sintéticas/uso terapéutico , Soporte de Peso
13.
J Med Eng Technol ; 41(2): 115-121, 2017 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-27696920

RESUMEN

Short dental implants have been used as an attempt to avoid bone grafts surgery, however there are few literature reports that evaluate changes to their design. Therefore, the aim of this study was to assess the effect of different short implant design on stress distribution through photoelastic analysis. Six external hexagon (5 × 5 mm) short dental implants with different design were used. Each group was treated with a single crown and a three element fixed partial dental prosthesis, resulting in a total of 12 photoelastic models. The assembling photoelastic model-implant-prosthesis was set in a circular polariscope where loads of 100N were applied on the occlusal surface with a Universal Test Machine (UTM). The tension fringes were photographed and later assessed qualitatively by a graphic software (Adobe Photoshop). Less high-intensity fringes were observed on the short implants with triangular threads, short external hexagon and flat apical profile. In conclusion, the macrodesign influenced the amount of stress distributed to the bone when short dental implants are placed.


Asunto(s)
Implantes Dentales , Dentadura Parcial Fija , Estrés Mecánico , Fenómenos Biomecánicos , Humanos , Ensayo de Materiales , Diseño de Prótesis
14.
Mater Sci Eng C Mater Biol Appl ; 71: 755-763, 2017 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-27987770

RESUMEN

The material used for interim prostheses fabrication must present excellent physical properties for greater longevity in the face of environmental conditions, which can occur in the oral cavity. The purpose of this study was to evaluate the effect of a photopolymerized glaze on the physical and mechanical properties of polymers used for the fabrication of interim prostheses, before and after thermocycling and immersion in staining solutions. One hundred samples of composite and acrylic resins were fabricated: Dencor chemically activated acrylic resin (CAAR) (n=20) and heat-polymerized acrylic resin (HPAR) (n=20), Charisma (n=20), Structur (n=20), and Protemp (n=20). A mechanical polishing was performed on half of the samples, and a chemical polishing was performed on the remaining samples. Subsequently, all samples were submitted to thermocycling and immersion in coffee staining solution for 21days. Analysis of color and microhardness, as well as atomic force microscopy (AFM), scanning electron microscopy (SEM), and energy dispersive x-ray spectrometry (EDS) were performed. The data were submitted to repeated-measures analysis of variance (ANOVA), followed by the Tukey test (α=0.05) and the Student t-test (α=0.05). It was verified that the glaze decreased the chromatic alteration values, and increased the microhardness values of the samples, with the exception of the Charisma resin. The samples that did not receive chemical polishing had the greatest number of surface irregularities. This study concluded that the groups with glaze presented less color alteration. In addition, Charisma and Structur resins exhibited the greatest chromatic stability. As to the microhardness, the values were greater when the samples were treated with the glaze, with the exception of the Charisma group.


Asunto(s)
Luz , Polimerizacion , Polímeros/química , Prótesis e Implantes , Análisis de Varianza , Color , Dureza , Microscopía Electrónica de Rastreo , Espectrometría por Rayos X , Propiedades de Superficie
15.
J Prosthet Dent ; 117(5): 685-689, 2017 May.
Artículo en Inglés | MEDLINE | ID: mdl-27881311

RESUMEN

STATEMENT OF PROBLEM: The rehabilitation of patients after a maxillectomy involves the use of an obturator to seal oral-nasal-sinus communication and to facilitate mastication, swallowing, and speech. PURPOSE: The purpose of this in vitro study was to evaluate different attachment systems used for implant-retained obturators at dissipation loads and under shear forces. MATERIAL AND METHODS: Photoelastic models were fabricated with 3 external hexagon implants at the incisor, canine, and first molar regions. Subsequently, overdentures were made, and metal hooks were placed at the incisor and first molar regions to displace the prostheses in the vertical, anterior, and posterior directions, with a constant speed of 50 mm/min. A photoelastic model with an O-ring or bar-clip system was placed in a circular polariscope, and tested with a universal testing machine. The images were recorded and high-intensity fringes were counted using software. For strain gauge analysis, each strain gauge was placed horizontally at the mesial and distal sides of the implants. The registered strains were submitted to 2-way ANOVA (α=.05). RESULTS: The O-ring showed the lowest number of high-intensity fringes in photoelastic imaging, while the strain gauge analysis showed the lowest stress values in the bar-clip group (P=.007). CONCLUSIONS: The stress around titanium implant necks was more damaging to surrounding bone, while the bar-clip attachment system had a better biomechanical performance. The bar-clip presented the lowest strain values around the dental implants and few high-intensity fringes.


Asunto(s)
Retención de Prótesis Dentales/métodos , Prótesis Dental de Soporte Implantado , Análisis del Estrés Dental/métodos , Prótesis de Recubrimiento , Obturadores Palatinos , Modelos Dentales , Diseño de Dentadura , Técnicas In Vitro , Ensayo de Materiales , Propiedades de Superficie , Titanio
16.
Int J Prosthodont ; 29(3): 233-44, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27148982

RESUMEN

PURPOSE: This systematic review aimed to evaluate whether the survival rate and predictability of zirconia abutments are similar to those of titanium abutments for single implant crowns in the posterior area. MATERIALS AND METHODS: A systematic search of two databases (Medline/PubMed and Cochrane Library) was performed by two independent reviewers for articles published between January 2004 and July 2014. The electronic search was complemented by a hand search of the following journals from the same period: Journal of Periodontology, Clinical Oral Implants Research, International Journal of Prosthodontics, and International Journal of Oral and Maxillofacial Implants. Studies included were published in English, evaluated single implant crowns, and performed a mean observation ≥ 1 year. Any disagreement between the reviewers was solved by means of a discussion. Forest plot and funnel were used to compare zirconia and titanium abutments. RESULTS: The search strategy identified 669 studies. Of these, 11 studies were included and only 6 studies were selected for meta-analysis. The pooled results for fixed implant single crowns in posterior areas showed a 5-year success rate of 99.3% for zirconia abutments and 99.57% for titanium abutments. There was no statistical difference regarding veneer failure (P = .26). The pooled results of these studies showed that the mean bone loss was 0.38 ± 0.87 mm for zirconia and 0.2 ± 0.13 mm for titanium abutments. CONCLUSION: The use of zirconia abutments for single implant-fixed crowns in posterior regions is questionable due to the absence of long-term data. The short-term results of zirconia abutments regarding mechanical and biologic responses are similar to titanium abutments. Caution when using zirconia abutments in posterior regions is necessary until further clinical evidence shows favorable long-term results.


Asunto(s)
Pilares Dentales , Implantes Dentales de Diente Único , Materiales Dentales/química , Circonio/química , Arco Dental/anatomía & histología , Diseño de Prótesis Dental , Fracaso de la Restauración Dental , Humanos , Seguridad , Titanio/química
17.
J Med Eng Technol ; 40(2): 35-42, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-26783652

RESUMEN

Photoelastic analysis was used to evaluate the biomechanical behaviour of implant-supported, double-screwed crowns with different connection systems and cantilever lengths. Three models were made in PL-2 photoelastic resin and divided into six groups, on the basis of the implant connection system (external hexagon [EH] or Morse taper [MT]), type of abutment (Mini Pilar [Neodent, Curitiba, Paraná, Brazil] or "UCLA") and number of crowns in the cantilever (one or two). The implant-prosthesis unit was placed in a circular polariscope. Occlusal surfaces of the crowns were subjected to 100-N loads in the axial and oblique (45°) directions in a universal testing machine (EMIC). Generated stresses were recorded and analysed qualitatively in a graphics program (Adobe Photoshop). Under axial loading, all of the groups had similar numbers of fringes, which were increased when the crowns were subjected to oblique loading. The highest number of fringes was found during oblique loading in the EH + Mini Pilar group. In conclusion, although the type of implant connection system did not have a direct influence on the stress distribution for axial loading, the cantilever length did have a direct influence on stress distribution. Models with two crowns in the cantilever showed more stress, with a greater concentration of force on the cervical part of the implant.


Asunto(s)
Implantes Dentales , Fenómenos Biomecánicos , Ensayo de Materiales , Fotograbar , Estrés Mecánico
18.
J Med Eng Technol ; 39(6): 322-7, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26100976

RESUMEN

The aim of this study was evaluate the biomechanical behaviour of prostheses screwed into conventional (0° angulation) and pre-angled experimental (8, 12 and 20°) external hexagon implants (13 × 4 mm) by photoelastic analysis. Eight casts were made in photoelastic resin. Casts were divided into groups of single crowns or three combined elements. Each unit was positioned in a circular polariscope. By using a universal testing machine, 100 N loads were applied in the axial and oblique (45°) directions to fixed points on the occlusal surfaces of the crowns. Generated stresses were recorded photographically and analysed qualitatively in a graphics program. In single-element prostheses, the number of high-stress fringes increased with increasing implant angle. However, in three-element prostheses, there was no difference in the stress distribution with implant angle, except for the 12° implant that had a higher degree of stress. For the other groups pre-angulation of the implant increases the concentration and intensity of stresses for single prosthesis and has similar stress distribution in three-element fixed prostheses.


Asunto(s)
Implantes Dentales , Huesos/fisiología , Modelos Biológicos , Estrés Mecánico
19.
Ann Med Surg (Lond) ; 4(2): 200-3, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-26052437

RESUMEN

INTRODUCTION: The treatment of orofacial tumors may cause facial deformities by losses of structures that affect basic functions, i.e. feeding, speech, and the reduction of patient self-steam. PRESENTATION OF CASE: A white male patient was diagnosed with epidermoid cancer on the mandibular alveolar ridge with infiltration staging IV A. The patient was submitted to a mandibulectomy associated with a complete extraction of mandibular teeth. For rehabilitation, a conventional denture for the mandibular arch and a removable partial denture for the maxillary arch were fabricated. A correct occlusal adjustment and a satisfactory amount of alveolar bone was favorable for conventional dentures of the prostheses bases improve their retention and stability. After one year of follow-up, the patient was adapted to the prostheses, satisfied with their retention, and reported an improvement on his feeding. DISCUSSION: The prosthetic rehabilitation of patients after a partial mandibulectomy is essential for their self-steam. Conventional dentures may have their retention and stability improved if they are well fabricated, recorded and have a balanced occlusion. CONCLUSION: A correct occlusal adjustment and an adequate retention of the prostheses bases may improve their retention and stability. Patients without xerostomy and with a satisfactory amount of alveolar bone may have a favorable prognosis for conventional dentures.

20.
Case Rep Dent ; 2015: 704348, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25705525

RESUMEN

The success of rehabilitation will not depend on just clinical procedures. A proper dental technique (ceramist) is required as well as the respect for some biomimetic principles to obtain the desired final result. This study has the purpose of describing a prosthetic rehabilitation with laminate veneers and all-ceramic crowns of a patient unsatisfied with a previous esthetic treatment because of the negligence of some biomimetic principles. A 45-year-old female patient was admitted to the dental clinic complaining about the lifelike appearance of her all-ceramic restorations. Before the fabrication of new restorations, a mock-up was conducted to verify the patient's satisfaction. A ceramist conducted all the fabrication process so that surface characterizations could be visually verified and the lifelike appearance of natural tooth could be reproduced. After the cementation procedure, the patient reported being satisfied with the lifelike appearance of the new restorations. Based on the clinical findings of the present case report, it can be concluded that the reproduction of the lifelike esthetic appearance of natural teeth and the visualization of the final results before definitive procedures are essential to obtain the clinical success.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...