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1.
Artículo en Inglés | MEDLINE | ID: mdl-33223377

RESUMEN

INTRODUCTION: Computer-aided design and manufacturing (CAD-CAM) systems have assisted orthodontists to position brackets virtually. The purpose of this study was to evaluate if a CAD-CAM system could predict the orthodontic treatment outcome of patients with Angle Class I malocclusion with mild crowding or spacing and with no need for orthodontic extraction. METHODS: Using the American Board of Orthodontics Cast-Radiograph Evaluation (ABO-CRE) and color map superimposition, the treated occlusion was compared with the virtual final occlusion of 24 young adults with Class I occlusion. Using eXceed software (eXceed, Witten, Germany), we created the final occlusion prediction for each patient (virtual set up group). A digital model of the final occlusion of each patient was created (treated occlusion group). ABO-CRE score was used to compare groups. In addition, a color map was created for all subjects to access the mean and range values between the virtual set up model and treated occlusion model of each patient. Random and systematic errors were calculated. In addition, chi-square and t test were used. RESULTS: Comparisons between virtual set up occlusion and treated occlusion showed statistically significant differences in 3 out of 7 measurements: interproximal contact score was larger for treated than virtual occlusion (0.45 mm and 0.04 mm, respectively), and the treated occlusion showed larger values than the virtual occlusion for occlusal contacts (14.13 mm and 7.62 mm, respectively) and overjet (7.37 mm and 0.66 mm, respectively). Although the treated occlusion showed a larger score than the virtual occlusion (50.41 mm and 34.58 mm, respectively), there is no significant difference between both. Root angulation decreased (from 1.95 ± 1.29 to 0.65 ± 0.71) because of the treatment. CONCLUSIONS: ABO-CRE overall score presents no difference between groups. In addition, CAD-CAM setup occlusion closely predicts the final teeth alignment and leveling with interarch relationships showing less ABO-CRE score deduction.

2.
Braz Dent J ; 31(6): 657-663, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33237238

RESUMEN

The aim of this study was to evaluate the effect of cleaning solutions on the retention force of o-ring-type overdenture attachments. The effect of four solutions on nitrile rings were evaluated: Cepacol (C), Cepacol with fluoride (CF), Listerine (L) and 0.05% sodium hypochlorite (SH); deionized water (DW) was used as a control. Matrices containing two implants and abutments and acrylic specimens with the metal capsules were obtained and divided into the groups. A simulation of 90 overnight immersions (8 h) was performed, and the tensile strength value was obtained at the beginning (T0) and in every 30 days (T1, T2 and T3) (n=6). In order to analyze o-ring surface damage after the immersions, a scanning electron microscopy (SEM) was used (n=1). For statistical analysis of the results, analysis of variance (ANOVA) and multiple comparisons with Bonferroni adjustment (test power=1.000; a=0.05) were used. There was a significant difference for the factors time (p<0.001), solution (p<0.001) and for the interaction time × solution (p<0.001). Considering the times of each solution, only for DW there was no significant loss of retention over time. Comparing the solutions in each moment, there was no difference among the solutions in T0. From T1, CF and SH provided less retention than DW (p<0.005). Through SEM it was possible to observe changes in the surface of the CF and SH nitrile o-rings. CF and SH should be avoided due to deleterious action in o-rings.


Asunto(s)
Prótesis de Recubrimiento , Hipoclorito de Sodio , Prótesis Dental de Soporte Implantado , Análisis del Estrés Dental , Retención de Dentadura , Ensayo de Materiales , Resistencia a la Tracción
3.
Braz. dent. j ; 31(6): 657-663, Nov.-Dec. 2020. tab, graf
Artículo en Inglés | LILACS-Express | LILACS, BBO - Odontología | ID: biblio-1132344

RESUMEN

Abstract The aim of this study was to evaluate the effect of cleaning solutions on the retention force of o-ring-type overdenture attachments. The effect of four solutions on nitrile rings were evaluated: Cepacol (C), Cepacol with fluoride (CF), Listerine (L) and 0.05% sodium hypochlorite (SH); deionized water (DW) was used as a control. Matrices containing two implants and abutments and acrylic specimens with the metal capsules were obtained and divided into the groups. A simulation of 90 overnight immersions (8 h) was performed, and the tensile strength value was obtained at the beginning (T0) and in every 30 days (T1, T2 and T3) (n=6). In order to analyze o-ring surface damage after the immersions, a scanning electron microscopy (SEM) was used (n=1). For statistical analysis of the results, analysis of variance (ANOVA) and multiple comparisons with Bonferroni adjustment (test power=1.000; a=0.05) were used. There was a significant difference for the factors time (p<0.001), solution (p<0.001) and for the interaction time × solution (p<0.001). Considering the times of each solution, only for DW there was no significant loss of retention over time. Comparing the solutions in each moment, there was no difference among the solutions in T0. From T1, CF and SH provided less retention than DW (p<0.005). Through SEM it was possible to observe changes in the surface of the CF and SH nitrile o-rings. CF and SH should be avoided due to deleterious action in o-rings.


Resumo O objetivo do estudo foi avaliar o efeito de soluções higienizadoras sobre a força de retenção de encaixes do tipo o-ring. Foram avaliadas quatro soluções: Cepacol (C); Cepacol com flúor (CF), Listerine (L), hipoclorito de sódio 0,05% (HS) e água deionizada (controle/AD) em o-rings de nitrilo. Matrizes contendo dois implantes e pilares e espécimes em acrílico com as cápsulas metálicas foram obtidas e divididas entre os grupos. Foi realizada a simulação de 90 imersões noturnas (8 h), sendo obtido o valor da resistência à tração no início e a cada 30 dias (T0, T1, T2 e T3) por meio da máquina de ensaios mecânicos (n=6). Microscopia eletrônica de varredura (MEV) foi utilizada para análise de danos na superfície do o´ring após a imersão (n=1). Para análise estatística dos resultados foi utilizada análise de variância (ANOVA) e múltiplas comparações com ajuste de Bonferroni (poder do teste=1,000; a=0,05). Houve diferença significante para os fatores tempo (p<0,001), solução (p<0,001) e para interação de tempo × solução (p<0,001). Considerando-se os tempos de cada solução, apenas AD não apresentou perda significativa de retenção ao longo do tempo. Comparando as soluções em cada momento, não houve diferença entre as soluções em T0. A partir de T1, CF e HS propiciaram menor retenção quando comparados à AD (p <0,005). Através do MEV foi possível observar alterações nas superfícies dos o-rings de nitrilo imersos em CF e HS. O Cepacol com flúor e hipoclorito de sódio devem ser evitados devido à ação deletéria nos o-rings.

4.
Dental Press J Orthod ; 25(1): 28-35, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32215475

RESUMEN

OBJECTIVE: The purpose of this study was to evaluate the effect of the Yd:YAG laser irradiation on orthodontic bracket base surface. Shear bond strength (SBS) values and sites of the bonding failure interfaces were quantified. METHODS: Brackets were divided into two groups: OP (One Piece - integral sandblast base) and OPL (One Piece - laser irradiation). The brackets were randomly bonded on an intact enamel surface of 40 bovine incisors. The SBS tests were carry out using a universal test machine. A stereomicroscopy was used to evaluate the adhesive remnant index (ARI), and surface characterization was performed by scanning electron microscopy (SEM). Student's t-test was used to compare the SBS between the two groups (p< 0.05). Frequencies and chi-square analysis were applied to evaluate the ARI scores. RESULTS: OPL group showed higher value (p< 0.001) of SBS than OP group (43.95 MPa and 34.81 MPa, respectively). ARI showed significant difference (p< 0.001) between OPL group (ARI 0 = 100%) and OP group (ARI 0 = 15%). SEM showed a higher affinity between the adhesive and the irradiated laser base surface. CONCLUSIONS: Yd:YAG laser irradiation on bracket base increased SBS values, showing that bonding failure occurs at the enamel/adhesive interface. Laser-etched bracket base may be used instead of conventional bases in cases where higher adhesion is required, reducing bracket-bonding failure.


Asunto(s)
Recubrimiento Dental Adhesivo , Láseres de Estado Sólido , Soportes Ortodóncicos , Animales , Bovinos , Humanos , Metales , Resistencia al Corte , Propiedades de Superficie
5.
Dental press j. orthod. (Impr.) ; 25(1): 28-35, Jan.-Feb. 2020. tab, graf
Artículo en Inglés | LILACS-Express | LILACS | ID: biblio-1089830

RESUMEN

ABSTRACT Objective: The purpose of this study was to evaluate the effect of the Yd:YAG laser irradiation on orthodontic bracket base surface. Shear bond strength (SBS) values and sites of the bonding failure interfaces were quantified. Methods: Brackets were divided into two groups: OP (One Piece - integral sandblast base) and OPL (One Piece - laser irradiation). The brackets were randomly bonded on an intact enamel surface of 40 bovine incisors. The SBS tests were carry out using a universal test machine. A stereomicroscopy was used to evaluate the adhesive remnant index (ARI), and surface characterization was performed by scanning electron microscopy (SEM). Student's t-test was used to compare the SBS between the two groups (p< 0.05). Frequencies and chi-square analysis were applied to evaluate the ARI scores. Results: OPL group showed higher value (p< 0.001) of SBS than OP group (43.95 MPa and 34.81 MPa, respectively). ARI showed significant difference (p< 0.001) between OPL group (ARI 0 = 100%) and OP group (ARI 0 = 15%). SEM showed a higher affinity between the adhesive and the irradiated laser base surface. Conclusions: Yd:YAG laser irradiation on bracket base increased SBS values, showing that bonding failure occurs at the enamel/adhesive interface. Laser-etched bracket base may be used instead of conventional bases in cases where higher adhesion is required, reducing bracket-bonding failure.


RESUMO Objetivo: O objetivo do presente estudo foi avaliar o efeito da aplicação do laser Yd:YAG sobre a superfície metálica da base de braquetes ortodônticos, a resistência da colagem ao cisalhamento (RU) e os locais das falhas nas interfaces adesivas. Métodos: Os braquetes foram divididos em dois grupos, de acordo com o tipo de base: OP (One Piece - monobloco, base jateada) e OPL (One Piece - monobloco, base irradiada a laser). Foram selecionados 40 incisivos bovinos hígidos para a colagem de braquetes na superfície do esmalte. Os testes de RU foram realizados por meio de uma máquina de ensaio universal EMIC DL1000. O Índice de Adesivo Remanescente (ARI) e a caracterização das superfícies foram realizados empregando-se estereomicroscópio e microscópio eletrônico de varredura (MEV). O teste t de Student foi aplicado para comparar a RU entre os dois grupos (p< 0,05). O ARI foi avaliado por meio da análise de Frequência e teste do Qui-quadrado. Resultados: O grupo OPL obteve maiores valores de RU (p<0,001) do que o grupo OP (43,95 MPa e 34,81 MPa, respectivamente), e o ARI obteve diferença significativa (p<0,001) entre os grupos OPL (ARI 0 = 100%) e OP (ARI 0 = 15%). A análise proveniente do MEV mostrou alta interação adesiva entre a resina e a superfície metálica da base irradiada pelo feixe de laser. Conclusões: A irradiação com laser Yd:YAG sobre a superfície da base de braquetes metálicos aumentou os valores da RU, demonstrando que as falhas adesivas ocorreram na interface esmalte/adesivo. O uso de braquetes modificados com irradiação a laser pode ser adotado como alternativa aos braquetes com bases convencionais nos casos em que uma maior retentividade for requerida para reduzir as falhas de adesividade.

6.
Biofouling ; 35(2): 173-186, 2019 02.
Artículo en Inglés | MEDLINE | ID: mdl-30935231

RESUMEN

The chemical composition of biomaterials can drive their biological responses; therefore, this in vitro study aimed to evaluate the proteomic profile of the salivary pellicle formed on titanium (Ti) alloys containing niobium (Nb) and zirconium (Zr). The experimental groups consisted of Ti35NbxZr (x = 5 and 10 wt%) alloys, and commercially pure titanium (cpTi); titanium aluminium vanadium (Ti6Al4V) alloys were used as controls. The physical and chemical characteristics of the Ti materials were analysed. The proteomic profile was evaluated by liquid chromatography coupled with tandem mass spectrometry. Bacterial adhesion (2 h) of mixed species (Streptococcus sanguinis and Actinomyces naeslundii) was investigated as colony-forming units (n = 6). This paper reports the finding that salivary pellicle composition can be modulated by the composition of the Ti material. The Ti35NbxZr group showed a significant ability to adsorb proteins from saliva, which can favour interactions with cells and compatibility with the body.


Asunto(s)
Aleaciones/química , Película Dental/química , Niobio/química , Proteoma/análisis , Proteínas y Péptidos Salivales/análisis , Titanio/química , Circonio/química , Adsorción , Adhesión Bacteriana , Materiales Biocompatibles/química , Proteómica
7.
Ortho Sci., Orthod. sci. pract ; 12(47): 145-151, 2019. tab, ilus
Artículo en Inglés | BBO - Odontología | ID: biblio-1023059

RESUMEN

Os sistemas CAD/CAM, incluindo o sistema eXceed™, possibilitam aos ortodontistas a realização de diagnóstico, planejamento de casos clínicos e posicionamento virtual de bráquetes. A posição de cada acessório, determinada pelo software, é transferida para o modelo tridimensional do paciente sobre o qual um dispositivo de transferência para colagem indireta (CI) de bráquetes é produzido. A CI permite uma melhoria na precisão da colagem de acessórios ortodônticos, diminuindo o tempo e o custo do tratamento devido a uma menor necessidade de dobras de finalização e reposicionamento de bráquetes. O caso clínico apresentado tem o objetivo de apresentar um tratamento ortodôntico utilizando o método de CI com posicionamento virtual de bráquetes idealizado pelo sistema eXceed™. O posicionamento dos bráquetes programado pelo sistema eXceed™ permitiu um posicionamento "ideal" dos dentes dispensando a implementação de dobras de finalização e proporcionando uma oclusão equilibrada. Essa nova tecnologia demonstrou ser eficiente e eficaz, e o setup ortodôntico fornecido pelo sistema ficou acordante com o resultado final do tratamento ortodôntico (AU)


CAD/CAM systems, including the eXceed™ system, allow orthodontists to perform diagnosis, treatment plan, and brackets virtual positioning. The positioning of each bracket, determined by the software, is transferred to a tridimensional patient model enabling to build an indirect bonding (IB) tray. IB allows improvement in the ideal bracket positioning, decreasing treatment time and cost due to less detailed finishing bends and/or bracket repositioning. The clinical case report purpose is to present an orthodontic treatment using IB with virtual bracket positioning using eXceed™ system. The bracket virtual positioning from eXceed™ system allowed an ideal final teeth positioning eliminating detailed finishing bends and reaching the ideal occlusion as planned. This new technology has shown to be efficient and effective, and the virtual tridimensional orthodontic setup has been in agreement with the final treatment occlusion (AU)


Asunto(s)
Humanos , Masculino , Adulto , Aparatos Ortodóncicos , Ortodoncia Correctiva , Diseño Asistido por Computadora
8.
Ortho Sci., Orthod. sci. pract ; 12(48): 113-119, 2019. ilus, tab
Artículo en Portugués | BBO - Odontología | ID: biblio-1048713

RESUMEN

Resumo Introdução: Os sistemas CAD/CAM auxiliam ortodontistas na confecção de alinhadores estéticos e na colagem indireta (posicionamento virtual de bráquetes) em modelos digitais tridimensionais. Este estudo avaliou a precisão e validade do software eXceedTM. Métodos: Vinte modelos de gesso de pacientes foram digitalizados utilizando um escâner de mesa e os arquivos obtidos foram convertidos em estereolitografia pelo software OrthoAnalyserTM. Utilizando os modelos de gesso e digital, seis medidas foram aferidas: Largura Intermolares (LM), Largura Intercaninos (LC), Comprimento do Arco posterior (CA), Diâmetro da Coroa do Pré-Molar (DP), Altura da Coroa do Canino (AC) e Overjet (OJ). Os erros sistemáticos e aleatórios foram avaliados em análises das réplicas das mensurações. As diferenças foram avaliadas usando o teste t de Student. Os erros aleatórios foram quantificados usando o erro do método (V(Sd2/2n) e o Coeficiente de Correlação Intraclasse (ICC). Resultados: Duas das medidas das réplicas em modelos digitais (CA) e de gesso (LC) demostraram erros sistemáticos estatisticamente significativos. O ICC variou de 0,916 a 0,997. Os erros do método foram todos inferiores a 0,41 mm (0,22 mm). Os gráficos de Bland-Altman mostraram que as diferenças de repetitividade entre os dois métodos estavam dentro dos limites de concordância. Os valores DP (0,253 mm), LC (0,396 mm), AC (0,314 mm) e CA (0,359 mm) foram maiores em modelos de gesso do que nos modelos digitais. Conclusão: As medidas realizadas em ambos os métodos foram confiáveis e reprodutíveis, e as medidas dos modelos de gesso foram ligeiramente maiores do que os dos modelos digitais correspondentes (AU)


Abstract Introduction: CAD/CAM systems help orthodontists in the production of aesthetic aligners and in indirect bonding (virtual bracket positioning) in three-dimensional digital models. This study evaluated the accuracy and validity of the eXceedTM 3D software (Roosikrantsi, Tallinn, Estonia). Methods: Twenty patient plaster models were digitized by a desktop scanner, and the files obtained were converted to stereolithography by OrthoAnalyserTM software. Using the cast and digital models, six measurements were performed: Intermolar Width (LM); Intercanine Width (LC); Posterior Arch Length (CA); Premolar Crown Diameter (DP); Canine Crown Hight (AC) and Overjet (OJ). Intra-observer systematic differences between the replicates were described with mean absolute differences and standard errors (SE); differences were assessed using a paired Students t test. Random errors were quantified using the method error statistic (V[Sd2/2n]) and Intraclass Correlation Coefficient (ICC). Differences between methods was evaluated using Students t test. Results: Two of the measurements of the replicas in the digital model (CA) and in the plaster model (LC) showed statistically significant systematic errors. The ICC ranged from 0.916 to 0.997. The method errors were all less than 0.41 mm (0.22 mm). Bland-Altman plots showed that the differences of repeatability between the two methods were within the limits of agreement. The values DP (0.253 mm), LC (0.396 mm), AC (0.314 mm) and CA (0.359 mm) were higher in plaster models than in digital models. Conclusion: The measurements performed in both methods were reliable and reproducible, and plaster models measurements were slightly higher than those of the corresponding digital models. (AU)


Asunto(s)
Humanos , Masculino , Femenino , Adolescente , Adulto , Ortodoncia , Tecnología Odontológica , Diseño Asistido por Computadora , Modelos Dentales , Precisión de la Medición Dimensional
9.
Clin Implant Dent Relat Res ; 20(3): 274-279, 2018 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-29380490

RESUMEN

BACKGROUND: Changes in the macrogeometry of dental implants are known to influence primary stability and the osseointegration process. PURPOSE: The purpose of the present in vitro study was to evaluate the mechanical behavior of geometric changes in the apex region of dental implants. METHODS: Thirty-five cylindrical dental implants (Titamax Ti; Neodent) were machined at the apical third to reproduce the experimental groups: without apical cut (Wc), apical bi-split cut, apical tri-split cut, apical quadri-split cut (Qs). One (control group) (Titamax Ti Ex) (n = 7) without any modifications was added. The implants had the same final dimensions (4.1 x 11 mm2 ). All implants were inserted into artificial bone blocks and were evaluated by insertion torque and resonance frequency by ISQ values (Osstell). Two-tailed analysis of variance (One-way ANOVA) and Tukey's post-test (P < .05). RESULTS: Control and Qs implants showed a significant increase of the insertion torque (P < .001). For the resonance frequency, Wc and (control) implants had the greatest ISQ values. However, there's no significant difference between (control) and Qs for the ISQ values (P < .001). CONCLUSION: Within the limitations of the present study, the proposed geometries at the apical third of dental implants greatly influenced its insertion torque and primary stability in vitro.


Asunto(s)
Implantación Dental Endoósea , Implantes Dentales , Retención de Prótesis Dentales , Torque , Vibración , Fenómenos Químicos , Diseño de Prótesis Dental , Análisis del Estrés Dental , Fenómenos Geológicos , Técnicas In Vitro , Oseointegración , Propiedades de Superficie , Titanio
10.
Dent Mater ; 33(11): 1244-1257, 2017 11.
Artículo en Inglés | MEDLINE | ID: mdl-28778495

RESUMEN

OBJECTIVE: The aim of this study was to develop binary and ternary titanium (Ti) alloys containing zirconium (Zr) and niobium (Nb) and to characterize them in terms of microstructural, mechanical, chemical, electrochemical, and biological properties. METHODS: The experimental alloys - (in wt%) Ti-5Zr, Ti-10Zr, Ti-35Nb-5Zr, and Ti-35Nb-10Zr - were fabricated from pure metals. Commercially pure titanium (cpTi) and Ti-6Al-4V were used as controls. Microstructural analysis was performed by means of X-ray diffraction and scanning electron microscopy. Vickers microhardness, elastic modulus, dispersive energy spectroscopy, X-ray excited photoelectron spectroscopy, atomic force microscopy, surface roughness, and surface free energy were evaluated. The electrochemical behavior analysis was conducted in a body fluid solution (pH 7.4). The albumin adsorption was measured by the bicinchoninic acid method. Data were evaluated through one-way ANOVA and the Tukey test (α=0.05). RESULTS: The alloying elements proved to modify the alloy microstructure and to enhance the mechanical properties, improving the hardness and decreasing the elastic modulus of the binary and ternary alloys, respectively. Ti-Zr alloys displayed greater electrochemical stability relative to that of controls, presenting higher polarization resistance and lower capacitance. The experimental alloys were not detrimental to albumin adsorption. SIGNIFICANCE: The experimental alloys are suitable options for dental implant manufacturing, particularly the binary system, which showed a better combination of mechanical and electrochemical properties without the presence of toxic elements.


Asunto(s)
Aleaciones Dentales/síntesis química , Implantes Dentales , Niobio/química , Titanio/química , Circonio/química , Albúminas/química , Materiales Biocompatibles/síntesis química , Módulo de Elasticidad , Electroquímica , Dureza , Ensayo de Materiales , Microscopía de Fuerza Atómica , Microscopía Electrónica de Rastreo , Espectroscopía de Fotoelectrones , Espectrometría por Rayos X , Difracción de Rayos X
11.
Dental Press J Orthod ; 20(6): 89-96, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26691975

RESUMEN

OBJECTIVE: Evaluation of the force system produced by four brands of b-Ti wires bent into an elaborate design. METHODS: A total of 40 T-loop springs (TLS) hand-bent from 0.017 x 0.025-in b-Ti were randomly divided into four groups according to wire brand: TMATM(G1), BETA FLEXYTM (G2), BETA III WIRETM (G3) and BETA CNATM (G4). Forces and moments were recorded by a moment transducer, coupled to a digital extensometer indicator adapted to a testing machine, every 0.5 mm of deactivation from 5 mm of the initial activation. The moment-to-force (MF) ratio, the overlapping of the vertical extensions of the TLSs and the load-deflection (LD) ratio were also calculated. To complement the results, the Young's module (YM) of each wire was determined by the slope of the load-deflection graph of a tensile test. The surface chemical composition was also evaluated by an energy dispersive X-ray fluorescence spectrometer. RESULTS: All groups, except for G2, produced similar force levels initially. G3 produced the highest LD rates and G1 and G4 had similar amounts of overlap of the vertical extensions of the TLSs in "neutral position". G1 and G3 delivered the highest levels of moments, and G2 and G3 produced the highest MF ratios. b-Ti wires from G3 produced the highest YM and all groups showed similar composition, except for G2. CONCLUSION: The four beta-titanium wires analyzed produced different force systems when used in a more elaborate design due to the fact that each wire responds differently to bends.


Asunto(s)
Estrés Mecánico , Aleaciones Dentales , Ensayo de Materiales , Alambres para Ortodoncia , Titanio
12.
J. appl. oral sci ; 23(6): 571-579, Nov.-Dec. 2015. graf
Artículo en Inglés | LILACS | ID: lil-769823

RESUMEN

ABSTRACT Dental composites cured at high temperatures show improved properties and higher degrees of conversion; however, there is no information available about the effect of pre-heating on material degradation. Objectives This study evaluated the effect of pre-heating on the degradation of composites, based on the analysis of radiopacity and silver penetration using scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS). Material and Methods Thirty specimens were fabricated using a metallic matrix (2x8 mm) and the composites Durafill VS (Heraeus Kulzer), Z-250 (3M/ESPE), and Z-350 (3M/ESPE), cured at 25°C (no pre-heating) or 60°C (pre-heating). Specimens were stored sequentially in the following solutions: 1) water for 7 days (60°C), plus 0.1 N sodium hydroxide (NaOH) for 14 days (60°C); 2) 50% silver nitrate (AgNO3) for 10 days (60°C). Specimens were radiographed at baseline and after each storage time, and the images were evaluated in gray scale. After the storage protocol, samples were analyzed using SEM/EDS to check the depth of silver penetration. Radiopacity and silver penetration data were analyzed using ANOVA and Tukey’s tests (α=5%). Results Radiopacity levels were as follows: Durafill VS<Z-350<Z-250 (p<0.05). The depth of silver penetration into the composites ranked as follows: Durafill VS>Z-350>Z-250 (p<0.05). After storage in water/NaOH, pre-heated specimens presented higher radiopacity values than non-pre-heated specimens (p<0.05). There was a lower penetration of silver in pre-heated specimens (p<0.05). Conclusions Pre-heating at 60°C mitigated the degradation of composites based on analysis of radiopacity and silver penetration depth.


Asunto(s)
Resinas Compuestas/química , Calor , Calefacción/métodos , Plata/química , Análisis de Varianza , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Valores de Referencia , Espectrometría por Rayos X , Propiedades de Superficie , Factores de Tiempo , Agua/química
13.
Dental press j. orthod. (Impr.) ; 20(6): 89-96, Nov.-Dec. 2015. tab, graf
Artículo en Inglés | LILACS-Express | LILACS | ID: lil-770272

RESUMEN

Abstract Objective: Evaluation of the force system produced by four brands of b-Ti wires bent into an elaborate design. Methods: A total of 40 T-loop springs (TLS) hand-bent from 0.017 x 0.025-in b-Ti were randomly divided into four groups according to wire brand: TMATM(G1), BETA FLEXYTM (G2), BETA III WIRETM (G3) and BETA CNATM (G4). Forces and moments were recorded by a moment transducer, coupled to a digital extensometer indicator adapted to a testing machine, every 0.5 mm of deactivation from 5 mm of the initial activation. The moment-to-force (MF) ratio, the overlapping of the vertical extensions of the TLSs and the load-deflection (LD) ratio were also calculated. To complement the results, the Young's module (YM) of each wire was determined by the slope of the load-deflection graph of a tensile test. The surface chemical composition was also evaluated by an energy dispersive X-ray fluorescence spectrometer. Results: All groups, except for G2, produced similar force levels initially. G3 produced the highest LD rates and G1 and G4 had similar amounts of overlap of the vertical extensions of the TLSs in "neutral position". G1 and G3 delivered the highest levels of moments, and G2 and G3 produced the highest MF ratios. b-Ti wires from G3 produced the highest YM and all groups showed similar composition, except for G2. Conclusion: The four beta-titanium wires analyzed produced different force systems when used in a more elaborate design due to the fact that each wire responds differently to bends.


Resumo Objetivo: avaliar os sistemas de força produzidos por quatro marcas de fios de -Ti, dobrados em formas complexas. Métodos: quarenta molas T-Loop (TLS) dobradas à mão, confeccionadas a partir de fios de -Ti, calibre 0,017" x 0,025", foram aleatoriamente divididas em quatro grupos, de acordo com a marca do fio: TMA (G1), BETA FLEXY (G2), BETA III Wire (G3) e BETA CNA (G4). Forças e momentos foram registrados por um transdutor de momento - acoplado a um extensômetro digital, adaptado a uma máquina de ensaios -, a cada 0,5mm de desativação, a partir de 5mm da ativação inicial. A proporção momento-força (M/F), a sobreposição das extensões verticais das TLSs e a relação carga-deflexão (C/D) também foram calculadas. Para completar os resultados, o módulo de Young (MY) de cada fio foi determinado pelo declive no gráfico de carga-deflexão em um ensaio de tração. Ademais, a composição química da superfície foi avaliada por um espectrômetro de fluorescência de raios X por energia dispersiva. Resultados: todos os grupos, exceto o G2, produziram níveis de força semelhantes, inicialmente. O G3 produziu as maiores taxas de C/D, enquanto G1 e G4 tiveram quantidades similares de sobreposição das extensões verticais das TLSs em posição neutra. G1 e G3 geraram os mais altos níveis de momentos, enquanto G2 e G3 produziram os mais altos índices de M/F. Os fios -Ti do G3 produziram o maior MY, e todos os grupos apresentaram composição semelhante, exceto G2. Conclusão: os quatro fios de beta-titânio analisados produziram diferentes sistemas de forças, quando utilizados para formas mais complexas, devido ao fato de que cada fio responde de forma diversa à confecção de dobras.

14.
J Appl Oral Sci ; 23(6): 571-9, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26814459

RESUMEN

Dental composites cured at high temperatures show improved properties and higher degrees of conversion; however, there is no information available about the effect of pre-heating on material degradation. Objectives This study evaluated the effect of pre-heating on the degradation of composites, based on the analysis of radiopacity and silver penetration using scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS). Material and Methods Thirty specimens were fabricated using a metallic matrix (2x8 mm) and the composites Durafill VS (Heraeus Kulzer), Z-250 (3M/ESPE), and Z-350 (3M/ESPE), cured at 25°C (no pre-heating) or 60°C (pre-heating). Specimens were stored sequentially in the following solutions: 1) water for 7 days (60°C), plus 0.1 N sodium hydroxide (NaOH) for 14 days (60°C); 2) 50% silver nitrate (AgNO3) for 10 days (60°C). Specimens were radiographed at baseline and after each storage time, and the images were evaluated in gray scale. After the storage protocol, samples were analyzed using SEM/EDS to check the depth of silver penetration. Radiopacity and silver penetration data were analyzed using ANOVA and Tukey's tests (α=5%). Results Radiopacity levels were as follows: Durafill VSZ-350>Z-250 (p<0.05). After storage in water/NaOH, pre-heated specimens presented higher radiopacity values than non-pre-heated specimens (p<0.05). There was a lower penetration of silver in pre-heated specimens (p<0.05). Conclusions Pre-heating at 60°C mitigated the degradation of composites based on analysis of radiopacity and silver penetration depth.


Asunto(s)
Resinas Compuestas/química , Calefacción/métodos , Calor , Plata/química , Análisis de Varianza , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Valores de Referencia , Espectrometría por Rayos X , Propiedades de Superficie , Factores de Tiempo , Agua/química
15.
RSBO (Impr.) ; 11(2): 178-184, Apr.-Jun. 2014.
Artículo en Inglés | LILACS-Express | LILACS | ID: lil-778278

RESUMEN

Introduction and Objective: Photoelasticity consists of an experimental technique of stress analysis. This technique is very used in most different areas including Dentistry. This literature review presents the several applications of photoelastic technique in Dentistry as well as its advantages and disadvantages. Literature review: Based on this method of analysis, it is possible the verification of the stress distribution and deformation in structures with complex geometry as maxilla and mandible. It can be used to evaluate the distribution of stress on several types of prosthesis as removable partial denture systems with different retention systems, conventional implant prosthesis, overdentures and Brånemark protocols. Moreover, photoelasticity can be used to assess the stress generated by various orthodontic movements, different orthodontic systems and different materials (orthodontic wires). In addition, it is used to analyze different defects of maxillectomy, splint types on traumatized tooth and post-core restoration methods. This technique can also be used to assess dental instruments such as evaluation of different designs of periodontal probe. Conclusion: The photoelastic analysis has been a technique of great importance in health area studies, more specifically in Dentistry. Based on this method of analysis, it is possible to measure the stress distribution and deformation in structures with complex geometry as maxilla and mandible.

16.
Rev. odontol. UNESP (Online) ; 43(1): 46-51, Jan-Feb/2014. tab, graf
Artículo en Portugués | LILACS-Express | LILACS | ID: lil-707254

RESUMEN

INTRODUÇÃO : O adequado posicionamento tridimensional dos implantes é indispensável para garantir a previsibilidade no tratamento com implantes dentários. OBJETIVO : Analisar comparativamente o comportamento mecânico do sistema prótese/implante em região anterior de maxila, diferindo os sistemas de encaixe e posicionamento dos implantes. MATERIAL E MÉTODO : Utilizando um modelo prototipado de maxila, as situações estudadas foram: Grupo IC - implantes nos incisivos centrais e cantilever nos incisivos laterais; Grupo IL - implantes nos incisivos laterais e pônticos nos incisivos centrais; Grupo ICIL - implantes no incisivo central e no incisivo lateral, intercalados com elementos suspensos. Para cada situação estudada, foram utilizadas as três conexões protéticas: hexágono externo, hexágono interno e cone-Morse. O ensaio de ciclagem mecânica foi realizado com a aplicação de 100 N de carga e frequência de 15 Hz no cíngulo dos incisivos a 45° com o longo eixo do dente, para simular o movimento mastigatório. RESULTADO : No ensaio de ciclagem mecânica, todos os modelos de todos os grupos com os três tipos de conexões protéticas atingiram um milhão de ciclos sem que ocorresse ruptura do parafuso, do componente protético ou da estrutura metálica. CONCLUSÃO : Com a metodologia e as condições empregadas, pode-se concluir que o comportamento mecânico das reabilitações implantossuportadas foi semelhante para os diferentes posicionamentos dos implantes e diferentes conexões protéticas. .


INTRODUCTION : The adequate three-dimensional positioning of implants is essential to ensure predictability in dental implant treatment. PURPOSE : Was to comparatively evaluate the mechanical behavior of the system prosthesis/implant in the anterior maxilla, differing the prosthetic connection and the placement of implants. MATERIAL AND METHOD : By a maxilla prototyped model the situations were studied: Group IC- implants in the central incisor positions and cantilevers in the lateral incisor positions; Group IL - implants in the lateral incisor positions and pontics in the central incisor positions; Group ICIL one implant in a lateral and one in a central incisor position, with a pontic and a cantilever in the other positions. For each situations were used the prosthetic connections, external hexagon, internal hexagon and Morse-taper. In fatigue test was applied load 100N of frequency 15Hz in the incisors cingulum 45° to the long axis of the tooth to simulate a masticatory movement. RESULT : After the fatigue test all models of all groups with all three types of connections prosthetic reached 1 million cycles without rupture occurred screw, prosthetic component or metallic structure. CONCLUSION : According to methodology and conditions studied, can be concluded that the mechanical behavior of the implant-supported rehabilitation was similar to the different positions of the dental implants and the different prosthetic connections. .

17.
J Prosthet Dent ; 111(4): 301-9, 2014 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-24355510

RESUMEN

STATEMENT OF PROBLEM: In dental rehabilitations that involve implants, the number of implants is sometimes smaller than the number of lost teeth. This fact can affect the biomechanical behavior and success of the implants. PURPOSE: The purpose of this study was to investigate the mechanical behavior of different implant positions in the rehabilitation of the anterior maxilla. MATERIAL AND METHODS: Three-dimensional models of the maxilla were created based on computed tomography images for 3 different anterior prosthetic rehabilitations. In group IL, the implants were placed in the lateral incisor positions with pontics in the central incisor positions; in group IC, the implants were in the central incisor positions with cantilevers in the lateral incisor positions; and, in group ILIC, one implant was in a lateral incisor position and one was in a central incisor position, with a pontic and a cantilever in the remaining positions. A 150 N load was distributed and applied at the center of the palatal surface of each tooth at a 45-degree angle to the long axis of the tooth. The resulting stress-strain distribution was analyzed for each group. RESULTS: The lowest displacement of the prosthetic structure was observed in group IC, although the same group exhibited the largest displacement of the bone tissue. In the bone tissue, the von Mises stress was mainly observed in the cortical bone in all groups. The maximum value of the von Mises stress shown in the cortical tissue was 35 MPa in the implant that neighbors the cantilever in group ILIC. The maximum von Mises stress in the trabecular bone was 3.5 MPa. CONCLUSION: The prosthetic configuration of group IC limited the displacement of the prosthetic structure but led to greater displacement of the bone structure. The use of a cantilever increased the stress concentration in the implant and in the bone structure adjacent to the cantilever under the conditions studied here.


Asunto(s)
Arco Dental/patología , Implantes Dentales , Arcada Parcialmente Edéntula/rehabilitación , Maxilar/patología , Fenómenos Biomecánicos , Aleaciones de Cromo/química , Simulación por Computador , Pilares Dentales , Materiales Dentales/química , Prótesis Dental de Soporte Implantado , Diseño de Dentadura , Dentadura Parcial , Módulo de Elasticidad , Análisis de Elementos Finitos , Humanos , Imagenología Tridimensional/métodos , Incisivo , Modelos Biológicos , Estrés Mecánico , Propiedades de Superficie , Titanio/química , Tomografía Computarizada por Rayos X/métodos
18.
Biomed Mater ; 8(6): 065005, 2013 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-24280708

RESUMEN

The main aim of this work was to assess the electrochemical behavior of new Ti35Nb5Zr and Ti35Nb10Zr alloys in artificial saliva at 37 °C to verify if they are indicated to be used as biomaterials in dentistry as alternatives to Ti6Al4V alloys in terms of corrosion protection efficiency of the material. Electrochemical impedance spectroscopy (EIS) experiments were carried out for different periods of time (0.5-216 h) in a three-electrode cell, where the working electrode (Ti alloys) was exposed to artificial saliva at 37 °C. The near-surface region of the alloys was investigated using x-ray photoelectron spectroscopy (XPS). All alloys exhibited an increase in corrosion potential with the immersion time, indicating the growth and stabilization of the passive film. Ti35Nb5Zr and Ti6Al4V alloys had their EIS results interpreted by a double-layer circuit, while the Ti35Nb10Zr alloy was modeled by a one-layer circuit. In general, the new TiNbZr alloys showed similar behavior to that observed for the Ti6Al4V. XPS results suggest, in the case of the TiNbZr alloys, the presence of a thicker passive layer containing a lower fraction of TiO2 phase than that of Ti6Al4V. After long-term immersion, all alloys develop a calcium phosphate phase on the surface. The new TiNbZr alloys appear as potential candidates to be used as a substitute to Ti6Al4V in the manufacturing of dental implant-abutment sets.


Asunto(s)
Aleaciones/química , Aleaciones Dentales/química , Materiales Dentales/química , Titanio/química , Circonio/química , Corrosión , Implantes Dentales , Electroquímica , Humanos , Ensayo de Materiales , Espectroscopía de Fotoelectrones , Saliva Artificial , Propiedades de Superficie
19.
RSBO (Impr.) ; 10(1): 82-88, Jan.-Mar. 2013. tab
Artículo en Inglés | LILACS-Express | LILACS | ID: lil-695917

RESUMEN

Introduction and Objective: The aim of this study was to review the literature on the systems used to decontaminate the implant's surface. Different instruments have been proposed, but there is no agreement in the literature about which methods would be more efficient with no damage to the implant surface. It was reported the use of plastic, carbon fiber, stainless-steel and titanium curettes and also the use of other systems such as ultrasonic points with different tips, rubber cups and air abrasion. Literature review: In most of the studies, the injury caused on the titanium surface at the time of instrumentation was examined. In others, the cell adhesion on the titanium dental implants following instrumentation of the implant surface was observed. Moreover, to enhance cleaning around implants, ultrasonic systems were recently tested. Conclusion: Metal instruments can lead to major damage to implant surface, therefore, they are not indicated for decontamination of dental implants surfaces. Furthermore, non-metallic instruments, such as plastic curettes, rubber cups, air abrasion and some ultrasonic systems seem to be better choices to remove calculus and plaque of the sub- and supra-gingival peri-implant area. It is noteworthy that more studies evaluating the effects of these systems are required to establish best practices to be used in the treatment of patients with dental implants.

20.
Ortodontia ; 45(1): 25-32, jan.-fev. 2012. ilus, tab, graf
Artículo en Portugués | LILACS, BBO - Odontología | ID: lil-713851

RESUMEN

Esta pesquisa avaliou in vitro a resistência ao cisalhamentode bráquetes ortodônticos fotopolimerizados com o arco de plasma, odiodo emissor de luz (LED) e a luz halógena convencional em diferentestempos. Bráquetes foram colados em 60 pré-molares superioreshumanos, divididos em cinco grupos. Nos grupos 1 e 2 utilizou-se a luzarco de plasma por três e seis segundos, respectivamente; nos grupos3 e 4 utilizou-se o LED por cinco e dez segundos, respectivamente; nogrupo 5 utilizou-se a luz halógena por 40 segundos. Os corpos de provaforam armazenados em água destilada em temperatura ambiente e,após 24 horas dos procedimentos de colagem, foram submetidos aosensaios mecânicos na máquina universal MTS-Material Test System. Paraa complementação dos resultados, também foi realizada a avaliação e aclassificação do padrão de descolagem dos bráquetes utilizando o lAR.Os resultados foram analisados por meio da análise de variância (Anova,seguida do teste SNK de Tukey para comparação múltipla de médias.Nãohouve diferenças entre os grupos 2, 4 e 5, as quais foram maioresque as médias dos grupos 1 e 3, iguais entre si. Os escores do lAR nãomostraram diferenças quanto à interface de descolagem entre os trêstipos de luz em todos os tempos testados. A luz arco de plasma e o LEDpodem ser utilizados por tempos reduzidos, dentro de certos limites,em relação à luz halógena na colagem de bráquetes ortodônticos, semperda de resistência ao cisalhamento.


This study evaluated in vitro the shear bond strength ofbraekets bonded with xenon plasma are light, light-emitting diode (LED)and conventional halogen light using different curing times. Bracketswere bonded to the bueeal surfaee of 60 human maxillary premolarsalloeated to tive groups. In groups 1 and 2, the resin was cured with theplasma are for three and six seconds (5), respectively; in groups 3 and4, the LED was used for tive and ten 5, respectively; and in group 5, thehalogen light was used for 40 s. The specimens were stored in waterfor 24 hours and subjected to a shear force until bracket failure. Thedebonding pattern was classified according to the adhesive remnant index(ARI). The results were assessed by Anova and the SNK post-hoe test.No differenees were deteeted among groups 2, 4 and 5, whieh showedhigher averages than groups 1 and 3, whieh were not different betweenthemselves. The ARI scores showed no differenees among the three typesof light sourees in ali times tested. Plasma are and LED lights ean be usedwith shorter euring times, within certain limits, than conventional halogenlight for bonding orthodontie brackets, without decreasing bond strength.


Asunto(s)
Luces de Curación Dental , Curación por Luz de Adhesivos Dentales , Láseres de Semiconductores , Soportes Ortodóncicos , Resistencia al Corte , Diente Premolar , Fototerapia
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