RESUMO
OBJECTIVES: This study evaluated the effect of an alkaline solution and two 10-methacryloyloxydecyl dihydrogen phosphate (MDP)-based primer agents on bond strength to zirconia (yttria-stabilized tetragonal zirconium polycrystal [Y-TZP]) through the shear bond strength (SBS) test. MATERIALS AND METHODS: Sixty square-shaped Y-TZP samples were embedded in an acrylic resin mold, polished, and randomly assigned to one of six groups (n=10) according to treatment surface: group CR, no treatment (control); group NaOH, 0.5 M NaOH; group AP, Alloy Primer; group ZP, Z-Primer Plus; group NaOH-AP, 0.5 M NaOH + Alloy Primer; and group NaOH-ZP, 0.5 M NaOH + Z-Primer Plus. The resin cement (Rely X U100) was applied inside a matrix directly onto the Y-TZP surface, and it was light-cured for 40 seconds. The samples were stored in distilled water at 37°C for 24 hours prior to the test, which was performed in a universal machine at a crosshead-speed of 0.5 mm/min. The data were analyzed by one-way analysis of variance and Tukey tests (p<0.05). Light stereomicroscopy and scanning electron microscopy were used to assess the surface topography and failure mode. RESULTS: The SBS was significantly affected by the chemical treatment (p<0.0001). The AP group displayed the best results, and the use of NaOH did not improve SBS results relative to either AP or ZP. The samples treated with Alloy Primer displayed mainly mixed failures, whereas those conditioned with Z-Primer Plus or with 0.5 M NaOH presented a balanced distribution of adhesive and mixed failure modes. CONCLUSIONS: The use of a NaOH solution may have modified the reactivity of the Y-TZP surface, whereas the employment of a MDP/6-4-vinylbenzyl-n-propyl amino-1,3,5-triazine-2,4-dithione-based primer enhanced the Y-TZP bond strength.
Assuntos
Álcalis/química , Materiais Dentários/química , Metacrilatos/química , Cimentos de Resina/química , Ítrio/química , Zircônio/química , Compostos Inorgânicos de Carbono/química , Polimento Dentário/métodos , Análise do Estresse Dentário/instrumentação , Humanos , Cura Luminosa de Adesivos Dentários/métodos , Teste de Materiais , Microscopia Eletrônica de Varredura , Resistência ao Cisalhamento , Compostos de Silício/química , Hidróxido de Sódio/química , Estresse Mecânico , Propriedades de Superfície , Temperatura , Tionas/química , Fatores de Tempo , Triazinas/química , Água/químicaRESUMO
The aim of this study was to evaluate the fracture resistance of endodontically maxillary premolars restored with mesio-occlusal-distal (MOD) inlays made with ceramic (IPS-Empress 2) and ceromer (Targis) and luted with three different dual-cured resin cements (Enforce, Variolink II, Panavia F). Sixty maxillary premolars were randomly distributed into six groups, according to their mesio-distal and facio-lingual dimensions. The teeth were endodontically treated and MOD cavities prepared. After the restorations were cemented, the samples were thermocycled and submitted to an axial compressive load by the action of a rounded end steel cylinder contacting the incline planes of occlusal surfaces of the teeth. The mode of fracture was analysed with a microscope. The best results were found with the combinations (cement/restorative material) Enforce/Targis (107.57 kgf) and Enforce/Empress (90.21 kgf) followed by Variolink II/Targis (86.44 kgf)-Variolink II/Empress (84.07 kgf) and Panavia F/Targis (82.43 kgf)-Panavia F/Empress (76.73 kgf). Analysis of variance (P < 0.05) showed a significant difference between Enforce and Panavia cements regardless of the restorative material. Considering the same luting agent there was no statistically significant difference between the restorative materials. Fracture of lingual cusps occurred in 55 of the 60 teeth and most of them were of the cohesive type.
Assuntos
Dente Pré-Molar , Materiais Dentários , Silicatos de Alumínio , Preparo da Cavidade Dentária/métodos , Porcelana Dentária , Restauração Dentária Permanente/métodos , Análise do Estresse Dentário/métodos , Cimentos de Ionômeros de Vidro , Restaurações Intracoronárias , Teste de Materiais/métodos , Maxila , Cimentos de Resina , Cimento de SilicatoRESUMO
This study evaluated the influence of three cleaning agents on the bond strength of complete crowns cemented with zinc phosphate and polycarboxylate cements. For the polycarboxylate cement group, three cleaning agents were used: Tergentol; Tergentol + polyacrylic acid; Tergentol + citric acid. Zinc phosphate cement was used as a control group with Tergentol. There were no statistically significant differences of mean retentive force for either cement regardless of the test conditions. The marginal fit after cementation was also evaluated and the results of zinc polycarboxylate were lower than zinc phosphate cement and were statistically significant.
Assuntos
Coroas , Colagem Dentária/métodos , Resinas Acrílicas , Cimentação , Ácido Cítrico , Adaptação Marginal Dentária , Detergentes , Humanos , Teste de Materiais , Cimento de Policarboxilato , Irrigantes do Canal Radicular , Tensoativos , Cimento de Fosfato de ZincoRESUMO
Se presenta un caso de neurofibroma laringeo y su evolucion despues del tratamiento. Se hace una revision de la literatura mundial. Se trata de un nino de 3 años de edad, quien desde el periodo neonatal presenta obstruccion laringea progresiva hasta presentar un cuadro obstructivo agudo al momento de su consulta, requiriendo traqueostomia. Se practicó laringoscopia directa y biopsia de una masa lisa, redondeada, submucosa que ocupa el repliegue ariepiglotico y aritenoides izquierdo, con resultado de neurofibroma con degeneracion mixoide. Se extirpa el tumor mediante faringotomia infrahioidea y se obtiene un diagnostico definitivo de neurofibroma plexiforme de laringe. El paciente evoluciona satisfactoriamente sin evidencias hasta la presente de recidivas. No se encontraron estigmas de la enfermedad de Von Recklinghausen ni antecedentes familiares de esta enfermedad. Los tumores neurogenicos de la laringe son muy raros en nuestro medio como en el resto del mundo segun la literatura medica
Assuntos
Humanos , Masculino , Criança , Criança , Neurofibroma PlexiformeRESUMO
STATEMENT OF PROBLEM: Fracture of endodontically treated teeth has been of great interest because it is a common clinical occurrence. PURPOSE OF STUDY: This research evaluated the fracture resistance of endodontically treated first maxillary premolars restored with different metal restorations and bonded with Panavia Ex resin. MATERIAL AND METHODS: Fifty teeth were randomly divided into five groups with MOD tooth preparation: (1) inlay with an isthmus width of one third the intercuspal distance for a silver amalgam restoration (negative control), (2) inlay with an isthmus width equal to that in group 1, (3) inlay with an isthmus width of half the intercuspal distance, (4) equal to group 3 with lingual and proximal preparation, and (5) onlay (positive control). The cast restorations of groups 2, 3, and 4 were bonded with Panavia Ex resin and those from group 5 cemented with zinc phosphate cement. Samples were restored and subjected to thermocycling, and the teeth were submitted to an axial compressive force. RESULTS: The cast inlay restorations that bonded with Panavia Ex resin significantly elevated the fracture resistance of endodontically treated maxillary premolars compared with the silver amalgam restorations. However, teeth restored with cast onlay restorations cemented with zinc phosphate cements recorded the best results. CONCLUSION: The increase of fracture resistance by MOD inlay cast restoration bonded with Panavia Ex resin suggested valid clinical application within the conditions of this study.
Assuntos
Dente Pré-Molar , Ligas de Cromo/química , Colagem Dentária , Restaurações Intracoronárias , Cimentos de Resina/química , Tratamento do Canal Radicular , Fraturas dos Dentes/prevenção & controle , Análise de Variância , Cimentação , Força Compressiva , Amálgama Dentário/química , Revestimento para Fundição Odontológica/química , Preparo da Cavidade Dentária/classificação , Humanos , Teste de Materiais , Maxila , Fosfatos/química , Reprodutibilidade dos Testes , Tratamento do Canal Radicular/efeitos adversos , Termodinâmica , Cimento de Fosfato de ZincoRESUMO
Se logro el aislamiento de Toxoplasma gondii en una muestra de diafragma de un bovino clínicamente sano, sacrificado para ser destinado al consumo de la población en el Matadero Industrial Centro Occidental de Barquisimeto, estado Lara. La muestra fue inoculada en ratones blancos los cuales se dejaron en observación durante 30 días, al final de este período se inoculó otro lote de ratones, lográndose el aislamiento 7 días después del pasaje. con esto se confirma la infección inaparente por T.gondii en la especie bivina en Venezuela
Assuntos
Bovinos , Cricetinae , Camundongos , Animais , Bovinos , Educação em Saúde , Parasitologia , Toxoplasmose Animal/classificaçãoRESUMO
Three techniques of centric relation registration were compared using the "Jig" (LUCIA), the "Leaf-Gauge" (LONG JUNIOR) and an wax anterior guide. The casts were mounted and analysed in a Whip-Mix articulador. The results permitted to conclude that, from the statistical viewpoint, did not occurred significant differences among techniques and centric relation occurred in an area not in a point. Because of facility and quickness the technique advocated by LON JUNIOR is recommended.
Assuntos
Oclusão Dentária Central , Registro da Relação Maxilomandibular , Adolescente , Adulto , Relação Central , Instrumentos Odontológicos , Feminino , Humanos , MasculinoRESUMO
The objective of the negative carving technique is to develop properly the occlusal principles during fabrication of occlusal surfaces of temporary crowns or metalhi restorations.