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1.
Scand J Rheumatol ; 45(2): 135-45, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26398142

RESUMO

OBJECTIVES: To describe the clinical features, treatment response, and follow-up of a large cohort of Italian patients with immunoglobulin (Ig)G4-related disease (IgG4-RD) referred to a single tertiary care centre. METHOD: Clinical, laboratory, histological, and imaging features were retrospectively reviewed. IgG4-RD was classified as 'definite' or 'possible' according to international consensus guidelines and comprehensive diagnostic criteria for IgG4-RD. Disease activity was assessed by means of the IgG4-RD Responder Index (IgG4-RD RI). RESULTS: Forty-one patients (15 females, 26 males) were included in this study: 26 with 'definite' IgG4-RD and 15 with 'possible' IgG4-RD. The median age at diagnosis was 62 years. The median follow-up was 36 months (IQR 24-51). A history of atopy was present in 30% of patients. The pancreas, retroperitoneum, and major salivary glands were the most frequently involved organs. Serum IgG4 levels were elevated in 68% of cases. Thirty-six patients were initially treated with glucocorticoids (GCs) to induce remission. IgG4-RD RI decreased from a median of 7.8 at baseline to 2.9 after 1 month of therapy. Relapse occurred in 19/41 patients (46%) and required additional immunosuppressive drugs to maintain long-term remission. Multiple flares occurred in a minority of patients. A single case of orbital pseudotumour did not respond to medical therapy and underwent surgical debulking. CONCLUSIONS: IgG4-RD is an elusive inflammatory disease to be considered in the differential diagnosis of isolated or multiple tumefactive lesions. Long-term disease control can be achieved with corticosteroids and immunosuppressive drugs in the majority of cases.


Assuntos
Doenças Autoimunes/imunologia , Glucocorticoides/uso terapêutico , Imunoglobulina G/imunologia , Imunossupressores/uso terapêutico , Pancreatite/imunologia , Sialadenite/imunologia , Idoso , Doenças Autoimunes/complicações , Doenças Autoimunes/tratamento farmacológico , Estudos de Coortes , Procedimentos Cirúrgicos de Citorredução , Feminino , Humanos , Itália , Masculino , Pessoa de Meia-Idade , Pseudotumor Orbitário/etiologia , Pseudotumor Orbitário/imunologia , Pseudotumor Orbitário/cirurgia , Pancreatite/tratamento farmacológico , Pancreatite/etiologia , Recidiva , Indução de Remissão , Espaço Retroperitoneal , Estudos Retrospectivos , Sialadenite/tratamento farmacológico , Sialadenite/etiologia
2.
Soft Matter ; 11(20): 4022-33, 2015 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-25899456

RESUMO

Silica-styrene butadiene rubber (SBR) nanocomposites were prepared by using shape-controlled spherical and rod-like silica nanoparticles (NPs) with different aspect ratios (AR = 1-5), obtained by a sol-gel route assisted by a structure directing agent. The nanocomposites were used as models to study the influence of the particle shape on the formation of nanoscale immobilized rubber at the silica-rubber interface and its effect on the dynamic-mechanical behavior. TEM and AFM tapping mode analyses of nanocomposites demonstrated that the silica particles are surrounded by a rubber layer immobilized at the particle surface. The spherical filler showed small contact zones between neighboring particles in contact with thin rubber layers, while anisotropic particles (AR > 2) formed domains of rods preferentially aligned along the main axis. A detailed analysis of the polymer chain mobility by different time domain nuclear magnetic resonance (TD-NMR) techniques evidenced a population of rigid rubber chains surrounding particles, whose amount increases with the particle anisotropy, even in the absence of significant differences in terms of chemical crosslinking. Dynamic measurements demonstrate that rod-like particles induce stronger reinforcement of rubber, increasing with the AR. This was related to the self-alignment of the anisotropic silica particles in domains able to immobilize rubber.

4.
Radiol Med ; 116(3): 375-88, 2011 Apr.
Artigo em Inglês, Italiano | MEDLINE | ID: mdl-21225363

RESUMO

PURPOSE: This study sought to evaluate the diagnostic accuracy of surface-coil 3T magnetic resonance (MR) imaging in the preoperative study of patients with rectal cancer. MATERIALS AND METHODS: Thirty patients with histologically proven rectal cancer underwent surface-coil 3T MR imaging with sagittal, paracoronal and para-axial T2-weighted turbo spin echo (TSE) sequences. Slice thickness was 3 mm without gap, field of view 24 cm, matrix 400 × 512. Images were assessed for infiltration of the rectal wall, perirectal fat and pelvic structures. Tumours were staged according to the TNM system, and the MR imaging results were correlated with histopathology. RESULTS: In the patients who underwent MR imaging before and after radiotherapy (group 1), the diagnostic accuracy of 3T MR imaging was 88% for T2, 94% for T3 and 88% for T4 cancers. In those who underwent surgical treatment without preoperative radiotherapy (group 2), the diagnostic accuracy was 90% for T2, 87% for T3 and 87% for T4 cancers. CONCLUSIONS: The high signal-to-noise ratio coupled with a large field of view enables surface-coil 3T MR imaging to achieve high levels of diagnostic accuracy in the local staging of rectal cancer, and in particular in assessing infiltration of mesorectum and mesorectal fascia.


Assuntos
Imageamento por Ressonância Magnética/instrumentação , Neoplasias Retais/patologia , Biópsia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Invasividade Neoplásica , Estadiamento de Neoplasias , Neoplasias Retais/radioterapia , Neoplasias Retais/cirurgia
5.
Proc Inst Mech Eng H ; 225(3): 296-302, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21485330

RESUMO

In this paper, the complete procedure to design and construct reusable moulds for implant-based ear prosthesis and manufacture substructures by means of a computer aided design-computer aided manufacturing (CAD-CAM) procedure and rapid prototyping (RP) technology is presented. The scan of the healthy ear, the virtual superimposition of its mirrored image on to the defective side, and the rapid manufacturing of the substructure and of the mould eliminate several steps of traditional procedures (wax, stone, try-in). Moreover, the precise design and customization of the substructure is presented, with the original and engineered shape for the retention of the silicone. The time and cost saving results of this protocol are presented together with a discussion of the main design features that make the prosthesis a stable and reproducible system to improve rehabilitation of patients with auricular defects or absence.


Assuntos
Engenharia Biomédica/métodos , Desenho Assistido por Computador , Orelha Externa/anatomia & histologia , Próteses e Implantes , Desenho de Prótese/métodos , Diagnóstico por Imagem , Humanos , Lasers , Modelos Anatômicos
6.
Eur J Cancer Care (Engl) ; 18(1): 97-101, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19473226

RESUMO

The computer-aided design of a nasal prosthesis based on pre-operative virtual laser scanning of the affected site was virtually adapted to the post-operative laser-scanned surface. The designed volume of the nose was rapidly prototyped and used to fabricate a provisional prosthesis and a computed tomography diagnostic template to check the available premaxilla bone for implants. The mould for the nasal prosthesis was prototyped using a computer-aided design and manufacturing (CAD-CAM) procedure. In addition, the mesiostructure of an eyeglasses-supported provisional prosthesis was also designed and prototyped using CAD-CAM procedures.


Assuntos
Carcinoma de Células Escamosas/cirurgia , Desenho Assistido por Computador , Deformidades Adquiridas Nasais/reabilitação , Neoplasias Nasais/cirurgia , Desenho de Prótese/métodos , Humanos , Processamento de Imagem Assistida por Computador , Tomografia Computadorizada por Raios X
7.
J Prosthodont Res ; 63(1): 100-104, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30385331

RESUMO

PURPOSE: To evaluate the influence of the preparation design and spacing parameters on the risk of chipping of crowns made by CEREC Bluecam before cementation. METHODS: A knife-edge preparation and a chamfer preparation were made on upper premolars. The teeth were scanned and two Co-Cr alloy replicas were made. Fifteen full crowns were manufactured for four groups using CEREC. The groups differed in type of preparation (knife-edge (KE) or chamfer (CHA)) and spacing parameters: spacer (0 or 150µm), marginal adhesive gap (10 or 50 or 150µm) and margin thickness (0 or 300µm). The four groups were: CHA 150 (spacer)- 50 (marginal adhesive gap)- 0 (margin thickness), KE 150-50-0, KE 150-50-300 and KE 150-150-300. The crowns were loaded before cementation by using an Instron machine to simulate the masticatory load applied during a trial. Differences in means were compared using two-way ANOVA and a post-hoc test (Tukey Test). The level of significance was set at P=0.05. RESULTS: The fracture values, ordered from least to most resistant, were: KE 150-50-300 group, CHA 150-50-0 group, KE 150-50-0 group and KE 150-150-300 group. Two-way ANOVA revealed statistically significant differences between pairs of means (p<0.05). Tukey's test showed that restorations of the KE 150-150-300 group can withstand a load significantly higher than that of other groups (p<0.01). In this group, the failures were mostly minor chippings, while the other groups had mostly major chippings and fractures. CONCLUSIONS: Marginal adhesive gap can affect the trial of a full crown.


Assuntos
Cimentação , Resinas Compostas , Coroas , Adaptação Marginal Dentária , Planejamento de Prótese Dentária/métodos , Falha de Restauração Dentária , Cimentos de Resina , Desenho Assistido por Computador , Análise do Estresse Dentário , Risco
8.
Int J Oral Maxillofac Surg ; 37(5): 478-80, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-18276115

RESUMO

A recurring problem during prosthetic rehabilitation following reconstruction by means of a vascularized fibula flap, after ablation of tumors affecting the facial skeleton, is the hyperplastic granulomatous reactive tissue that forms around the prosthetic abutments of the implant. The features of this phenomenon seem to be directly related to the characteristics of the peri-implant tissue and to the material from which the prosthetic abutments are manufactured. Two main ways of avoiding this are proposed. 1) Skin grafts around implants seem to inhibit the overgrowth of granulomatous tissue. 2) Acrylic provisionals should be avoided and substituted with complete metal-ceramic restoration.


Assuntos
Implantes Dentários/efeitos adversos , Hiperplasia Gengival/etiologia , Hiperplasia Gengival/prevenção & controle , Procedimentos de Cirurgia Plástica/efeitos adversos , Retalhos Cirúrgicos , Resinas Acrílicas/efeitos adversos , Adolescente , Adulto , Transplante Ósseo/efeitos adversos , Dente Suporte/efeitos adversos , Fíbula/irrigação sanguínea , Fíbula/transplante , Granuloma de Corpo Estranho/etiologia , Granuloma de Corpo Estranho/prevenção & controle , Humanos , Masculino , Neoplasias Mandibulares/cirurgia , Neoplasias Maxilares/cirurgia , Ligas Metalo-Cerâmicas , Transplante de Pele , Retalhos Cirúrgicos/irrigação sanguínea
9.
Int Endod J ; 41(8): 651-7, 2008 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-18702764

RESUMO

AIM: To evaluate the biocompatibility of a resin-based endodontic filler (RealSeal) using the indirect cytotoxicity test. METHODOLOGY: Human gingival fibroblasts were cultured ex vivo. Pellets of the materials to be tested were incubated for 24, 48, and 72 h at 37 degrees C under sterile conditions to obtain their eluates. The fibroblasts were exposed to either diluted (50%) or undiluted eluates for 24 h. A culture medium with foetal calf serum was added to the control wells. Cell viability was estimated by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide method. The data concerning cell viability were statistically analyzed using one-way anova test and Bonferroni multiple comparisons test. RESULTS: Eluates obtained after 24 h of incubation with the resin filler did not reduce cellular viability. An increase in cellular viability, as compared with control cells, was observed in the gutta-percha group. The undiluted eluate from the polyether material was cytotoxic, causing an 82 +/- 4% decrease in cellular viability. Eluates obtained after 48 h of incubation with the resin filler increased cellular viability, whereas the polyether significantly reduced viability. Gutta-percha did not cause any detectable change. After 72 h of incubation the eluate of the resin filler caused an increase in cellular viability, as did gutta-percha, whereas polyether caused a significant decrease. CONCLUSIONS: RealSeal resin filler was nontoxic in this laboratory model. Further investigations are necessary to verify its usefulness in clinical applications.


Assuntos
Sobrevivência Celular/efeitos dos fármacos , Resinas Compostas/efeitos adversos , Gengiva/efeitos dos fármacos , Materiais Restauradores do Canal Radicular/efeitos adversos , Células Cultivadas , Fibroblastos/efeitos dos fármacos , Gengiva/citologia , Guta-Percha/efeitos adversos , Humanos
11.
Colloids Surf B Biointerfaces ; 157: 26-30, 2017 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-28570988

RESUMO

This study aims to deepen the knowledge on tear film properties by the development of a protocol for analyses of Photon Correlation Spectroscopy (PCS) on human tears and by the comparison between PCS results obtained on tears of contact lens wearers and non-wearers. Tears (5µL) were collected by a glass capillary. The analyses provide the hydrodynamic diameter of tear components by analyzing intensity fluctuations in time of scattered light. PCS appears a promising technique for studying tear features and for shedding light on specific eye conditions, such as on the clinical effects of CL wear. In fact, statistical difference (p<0.001) was found between the measured mean hydrodynamic diameter of tear components of wearers and non-wearers, the resulting value significantly higher for CL wearers. The scenario does not substantially change after (25±5)min from the CL removal. The difference is attributed to changes in the interactions between tear constituents due to CL wear. In order to get deeper insights on the influence of CL wear on aggregation and structure of tear components, a preliminary Electron Spin Resonance (ESR) investigation was performed, monitoring Fe3+ species. ESR spectra on tears of both CL wearers and non-wearers showed the presence of intense signals, probably associated to iron (III) centers in proteins such as lactoferrin, and a weaker resonance attributable to Fe3+ species interacting with S-S bridges of lysozyme. Differences in ESR spectra between CL wearers and non-wearers were detected and tentatively ascribed to changes in coordination or in local environment of Fe3+ centers connected to aggregation phenomena induced by CL wear, which promote their interaction with other neighboring iron species.


Assuntos
Espectroscopia de Ressonância de Spin Eletrônica/métodos , Lágrimas/química , Adulto , Lentes de Contato , Feminino , Humanos , Hidrodinâmica , Masculino
12.
Oper Dent ; 42(4): 436-444, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28402732

RESUMO

The aim of this study was to evaluate the effect of different production methods of resin and ceramic inlays on marginal and internal adaptation, adjustment time, and proximal contacts. Forty premolars were selected, embedded (their roots), and prepared to receive inlays that were made as follows (n=10): LaRe-digital impression with a Lava C.O.S. scanner, followed by milling of Lava Ultimate block (composite resin) in a milling center; CeRe-digital impression with a Cerec 3D Bluecam scanner, followed by milling of Lava Ultimate block in Cerec; CeDis-digital impression with a Cerec 3D Bluecam scanner, followed by milling of IPS e.max CAD block (lithium disilicate) in Cerec; and PresDis-impression with polyvinyl siloxane, inlay made using the lost wax technique and IPS e.max Press pressed ceramic (lithium disilicate). Marginal and internal adaptations were measured using the replica technique. The inlay adjustments were performed using diamond burs in a contra-angle hand piece, and the time for adjustment was recorded using a timer, in seconds. The tightness of the proximal contact was measured using standardized metal blades. The statistical analyses for marginal fit data showed that at the cervical edge, CeDis (177.8 µm) had greater misfit than CeRe (116.7 µm), while all the groups had similar adaptation at the occlusal edge. The groups had similar internal fit at the pulpal wall, while LaRe (104.7 µm) > CeDis (66.7 µm) = CeRe (76.7 µm) at the axial wall. The groups restored with lithium disilicate ceramic took more time for adjustment when compared to the resin restorative material. The lowest proximal contact, in micrometers, was seen in the CeRe group (8.8 µm).


Assuntos
Resinas Compostas/química , Técnica de Moldagem Odontológica , Adaptação Marginal Dentária , Porcelana Dentária/química , Restaurações Intracoronárias , Dente Pré-Molar , Preparo da Cavidade Dentária , Materiais Dentários/química , Humanos , Técnicas In Vitro , Teste de Materiais , Fatores de Tempo
13.
Oper Dent ; 42(5): E121-E133, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28829934

RESUMO

OBJECTIVE: To evaluate the effect of different methods of silica deposition on the intaglio surface of yttrium oxide stabilized zirconia polycrystal (Y-TZP) crowns on the retentive strength of the crowns. METHODS: One hundred simplified full-crown preparations produced from fiber-reinforced polymer material were scanned, and 100 Y-TZP crowns with occlusal retentions were milled. Crown/preparation assemblies were randomly allocated into five groups (n=20) according to the treatment of the intaglio surfaces: TBS = tribochemical silica coating via air-abrasion with 30-µm silica-coated alumina particles; GHF1 = application of thin glaze layer + hydrofluoric acid (HF) etching for 1 minute; GHF5 = glaze application + HF for 5 minutes; GHF15 = glaze application + HF for 15 minutes; NANO = silica nanofilm deposition (5 nm) via magnetron sputtering. All groups received a silane application. The surfaces of the preparations (polymer) were conditioned with 10% HF for 30 seconds and silanized. The crowns were cemented with resin cement, thermocycled (12,000 cycles; 5°C/55°C), stored for 60 days, and subjected to a retentive strength test (0.5 mm/min until failure). The retention data (MPa) were analyzed using one-way analysis of variance, Tukey tests, and Weibull analysis. Failures were classified as 50C (above 50% of cement in the crown) and 50S (above 50% of cement on the substrate). RESULTS: The TBS (5.6±1.7 MPa) and NANO groups (5.5±1 MPa) had higher retentive strength than the other groups (p<0.0001) and had the highest values of characteristic strength. There was no difference in Weibull modulus, except for the GHF1 group (lower values). The TBS and GHF15 groups, respectively, had 60% and 70% of their failures classified as 50C, while most of the other groups had 50S failures. CONCLUSION: Tribochemical silica coating and silica nanofilm deposition on the inner surface of zirconia crowns promoted a higher retentive strength.


Assuntos
Coroas , Dióxido de Silício/administração & dosagem , Ítrio , Zircônio , Colagem Dentária/métodos , Retenção em Prótese Dentária/métodos , Falha de Restauração Dentária , Análise do Estresse Dentário , Humanos
14.
J Biomed Mater Res B Appl Biomater ; 105(4): 723-734, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-26708554

RESUMO

Three-dimension (3D) scaffolds for bone tissue regeneration were produced combining three different phases: nanometric hydroxyapatite (HA) was synthesized by precipitation method and the crystals nucleation took place directly within collagen fibrils following a biologically inspired mineralization process; polycaprolactone was employed to give the material a 3D structure. The chemico-physical analysis carried out to test the material's properties and composition revealed a high similarity in composition and morphology with biologically mineralized collagen fibrils and a scaffold degradation pattern suitable for physiological processes. The micro- computerized tomography (micro-CT) showed 53.53% porosity and a 97.86% mean interconnected pores. Computer-aided design and computer-aided manufacturing (CAD-CAM) technology was used for molding the scaffold's volume (design/shape) and for guiding the surgical procedure (cutting guides). The custom made scaffolds were implanted in sheep mandible using prototyped surgical guides and customized bone plates. After three months healing, scanning electron microscopy (SEM) analysis of the explanted scaffold revealed a massive cell seeding of the scaffold, with cell infiltration within the scaffold's interconnected pores. The micro-CT of the explanted construct showed a good match between the scaffold and the adjacent host's bone, to shield the implant primary stability. Histology confirmed cell penetration and widely documented neoangiogenesis within the entire scaffold's volume. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 723-734, 2017.


Assuntos
Materiais Biomiméticos/química , Regeneração Óssea , Substitutos Ósseos/química , Durapatita/química , Mandíbula , Traumatismos Mandibulares , Alicerces Teciduais/química , Animais , Mandíbula/diagnóstico por imagem , Mandíbula/metabolismo , Traumatismos Mandibulares/diagnóstico por imagem , Traumatismos Mandibulares/metabolismo , Traumatismos Mandibulares/terapia , Teste de Materiais , Ovinos , Microtomografia por Raio-X
15.
Minerva Stomatol ; 55(3): 145-9, 2006 Mar.
Artigo em Inglês, Italiano | MEDLINE | ID: mdl-16575385

RESUMO

The rehabilitation of the mandible after ablation cancer surgery is a challenge. Furthermore, osteodistraction in the microvascular fibula flap makes it difficult to predict adequate bone lengthening. The aim of this article is to evaluate a protocol used to manufacture templates for measuring osteodistraction, in terms of force vectors and definitive height. An accurate prosthetic wax-up with guide pins measuring the quantity of bone lengthening must be performed to manufacture the template. This device may be used to establish the end of the osteo-distraction in respect to the vertical dimension of the definitive occlusion.


Assuntos
Aumento do Rebordo Alveolar/métodos , Neoplasias Mandibulares/cirurgia , Implante de Prótese Mandibular , Osteogênese por Distração/métodos , Osteossarcoma/cirurgia , Adolescente , Aumento do Rebordo Alveolar/instrumentação , Implantação Dentária , Humanos , Masculino , Prótese Mandibular , Osteogênese por Distração/instrumentação
16.
Minerva Stomatol ; 55(9): 493-502, 2006 Sep.
Artigo em Inglês, Italiano | MEDLINE | ID: mdl-17146428

RESUMO

AIM: The purpose of this study was to evaluate the effect of ceramic surface polishing procedure on the early dental biofilm formation on zirconium ceramics. METHODS: Twenty samples (discs shape) of tetragonal zirconium polycrystal stabilized with yttrium ceramics (Y-TZP) for LAVA system were fabricated (5 mm diameter and 1.5 mm thickness). Two patients with high level of dental hygiene were selected for this study. Oral devices covering the crowns of the upper premolars and molars were fabricated for each participant. Glazed and polished samples of Y-TZP ceramics were fixed on the vestibular and palatal zones of the devices. After 20 min (8 samples) and 1 h (8 samples) in the oral environment, the samples were removed and analyzed in a scanning electron microscope. The surface topographies of 4 ceramic samples (2 glazed and 2 polished) were analyzed (control group: without exposition in oral environment). RESULTS: The glazed samples showed a more irregular surface than polished samples. Deposition of granular aggregates was verified on all the samples in the two times of the study analyzed. This granular material coated more intensely on irregular areas, and its thickness increased after 1 h. No difference was observed as to bacterial morphology in any time of the study. Cocci and rods-shaped prevailed. CONCLUSIONS: Glazed surfaces presented larger tendency to dental biofilm accumulation.


Assuntos
Aderência Bacteriana , Biofilmes , Polimento Dentário , Porcelana Dentária , Ligas Metalo-Cerâmicas , Zircônio , Adulto , Estudos de Casos e Controles , Humanos , Microscopia Eletrônica de Varredura
17.
Acta Otorhinolaryngol Ital ; 35(3): 198-201, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26246665

RESUMO

Free fibula flap is routinely used for mandibular reconstructions. For contouring the flap, multiple osteotomies should be shaped to reproduce the native mandibular contour. The bone segments should be fixed using a reconstructive plate. This plate is usually manually bent by the surgeon during surgery. This method is efficient, but during reconstruction it is complicated to reproduce the complex 3D conformation of the mandible and recreate a normal morphology with a mandibular profile as similar as possible to the original; any aberration in its structural alignment may lead to aesthetic and function alterations due to malocclusion or temporomandibular disorders. In order to achieve better morphological and functional outcomes, we have performed a customised flap harvest using cutting guides. This study demonstrates how we have performed customised mandibular reconstruction using CAD-CAM fibular cutting guides in 20 patients undergoing oncological segmental resection.


Assuntos
Desenho Assistido por Computador , Fíbula/transplante , Retalhos de Tecido Biológico , Reconstrução Mandibular/métodos , Coleta de Tecidos e Órgãos/métodos , Humanos
18.
Oper Dent ; 40(1): E1-E10, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25162722

RESUMO

This study evaluated the effect of the cement type (adhesive resin, self-adhesive, glass ionomer, and zinc phosphate) on the retention of crowns made of yttria-stabilized polycrystalline tetragonal zirconia (Y-TZP). Therefore, 108 freshly extracted molars were embedded in acrylic resin, perpendicular to their long axis, and prepared for full crowns: the crown preparations were removed and reconstructed using composite resin plus fiber posts with dimensions identical to the prepared dentin. The preparations were impressed using addition silicone, and Y-TZP copings were produced, which presented a special setup for the tensile testing. Cementation was performed with two adhesive resin cements (Multilink Automix, Ivoclar-Vivadent; RelyX ARC, 3M ESPE, St Paul, MN, USA), one self-adhesive resin cement (RelyX U100, 3M ESPE), one glass ionomer based cement (RelyX Luting, 3M ESPE), and one zinc phosphate cement (Cimento de Zinco, SS White, Rio de Janeiro, Brazil). For the resin cement groups, the inner surfaces of the crowns were subjected to three surface treatments: cleaning with isopropyl alcohol, tribochemical silica coating, or application of a thin low-fusing glass porcelain layer plus silanization. After 24 hours, all groups were subjected to thermocycling (6000 cycles) and included in a special device for tensile testing in a universal testing machine to test the retention of the infrastructure. After testing, the failure modes of all samples were analyzed under a stereomicroscope. The Kruskal-Wallis test showed that the surface treatment and cement type (α=0.05) affected the tensile retention results. The Multilink cement presented the highest tensile retention values, but that result was not statistically different from RelyX ARC. The surface treatment was statistically relevant only for the Multilink cement. The cement choice was shown to be more important than the crown surface treatment for cementation of a Y-TZP crown to a composite resin substrate.


Assuntos
Coroas , Cimentos de Resina/uso terapêutico , Ítrio/uso terapêutico , Zircônio/uso terapêutico , Bis-Fenol A-Glicidil Metacrilato/uso terapêutico , Coroas/normas , Corrosão Dentária , Falha de Restauração Dentária , Análise do Estresse Dentário , Cimentos de Ionômeros de Vidro/uso terapêutico , Humanos , Fosfatos/uso terapêutico , Polietilenoglicóis/uso terapêutico , Ácidos Polimetacrílicos/uso terapêutico , Resinas Sintéticas/uso terapêutico , Resistência à Tração , Compostos de Zinco/uso terapêutico
19.
Mol Biochem Parasitol ; 58(1): 1-6, 1993 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-8459822

RESUMO

Starting from previous evidence indicating that some features are shared by several Plasmodium falciparum chromosomal extremities, a subtelomeric region present on most P. falciparum 3D7 chromosomes has been mapped. It was shown to occupy about 40 kb, and to include the proximal portion of pPftel. 1, the only telomeric clone described for P. falciparum [12], the complete 21-bp repetitive cluster and some conserved sites (PstI, EcoRI) proximally located with respect to this cluster.


Assuntos
Cromossomos/ultraestrutura , DNA de Protozoário/ultraestrutura , Plasmodium falciparum/genética , Telômero/ultraestrutura , Animais , Sequência de Bases , Clonagem Molecular , Sondas de DNA , DNA de Protozoário/metabolismo , Desoxirribonucleases de Sítio Específico do Tipo II/metabolismo , Cariotipagem , Dados de Sequência Molecular , Mapeamento por Restrição , Análise de Sequência de DNA
20.
Mol Biochem Parasitol ; 69(2): 257-68, 1995 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-7770089

RESUMO

Walking and jumping procedures were employed to obtain a consensus map of the 35-40 kb subtelomeric region shared by many chromosomal extremities in Plasmodium falciparum strain 3D7, and to characterise the portions flanking the rep20 tract, which is known to contain tandemly repeated, apparently degenerate, 21-bp repeats. The borders of rep20 were shown to harbour short (possibly locally homogenised) patterns of non-degenerate 12-, 17-, 23- and 28-bp repeats. The central repetitious portion of the consensus map was estimated to be about 18 kb in length, and to be separated from the telomere by approx. 11 kb of non-repetitious sequence, maintained with high fidelity at different chromosomal ends. Several kilobases of similarly conserved, non-repetitious sequence flank rep20 on its proximal side. Computer analysis of the rep20 sequence suggested that a peculiar superhelical winding originates from the conservation of identical nucleotide groups in phase with the pitch of the double helix, overcoming the effect of repeat degeneration in in other positions of the 21-bp unit.


Assuntos
Plasmodium falciparum/genética , Animais , Sequência de Bases , Mapeamento Cromossômico , Passeio de Cromossomo , Clonagem Molecular , Sequência Consenso , DNA de Protozoário/química , DNA de Protozoário/genética , Dados de Sequência Molecular , Conformação de Ácido Nucleico , Sequências Repetitivas de Ácido Nucleico , Telômero/química , Telômero/ultraestrutura
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