Efeito de diferentes estratégias de reparo na resistência de união à resina composta e viabilidade celular de novos materiais cad/cam: estudo in situ
Introduction: New CAD/CAM blocks of resin, hybrid and ceramic restorative materials have been recently developed. However, the literature does not yet have a repair protocol for these materials against a cohesive fracture of the restorative material. Purpose: To determine the influence of surface...
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| Formato: | Dissertação |
| Idioma: | por |
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| Endereço do item: | https://repositorio.ufrn.br/jspui/handle/123456789/25375 |
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| Resumo: | Introduction: New CAD/CAM blocks of resin, hybrid and ceramic restorative materials have
been recently developed. However, the literature does not yet have a repair protocol for these
materials against a cohesive fracture of the restorative material. Purpose: To determine the
influence of surface treatment (diamond burs, abrasive jet Al2O3, COJET, and hydrofluoric
acid) and in situ aging on CAD/CAM shear bond strength (LU:Lava Ultimate / 3M, VE: Vita
Enamic / VITA and VS:VITA Suprinity / VITA) to the composite resin. Methodology: 390
blocks (6 x 5 x 2.5mm) were made, 130 of each restorative material. 300 samples were used
for the shear bond strength test, the other samples were used for extra analysis. Fifty samples
of each restorative material were embedded in total dentures in use, and after a period of 60
days (aging in situ), the 150 aged and 150 unripe samples were randomly divided (N = 30 / n
= 10) according to treatment carried out: 1. Diamond burs + Single Bond Universal (SUB); 2.
Diamond burs + silane + conventional adhesive; 3. Hydrofluoric acid 10% + silane +
conventional adhesive; 4. COJET + silane + conventional adhesive; 5. abrasive jet aluminum
oxide Al2O3 + silane + conventional adhesive. Then, Z350 (3M ESPE) composite resin
cylinders (: 2.37mm, height: 2mm) were built on the surface of the blocks. Subsequently,
the 300 specimens were then subjected to thermocycling (10,000 cycles, 50 / 550C) and then
to the shear test (50kgf, 0.5mm / min). After fracture, the failure analysis was performed in
stereomicroscope (20X). Additional samples of each restorative material were used for the
Vickers microhardness and Roughness (n = 10) analyzes for the two tests; analysis of fungal
cell viability (n = 10); scanning electron microscopy (SEM) analysis of the surface treatments
and EDS analysis (n = 10) for characterization of the same materials for the two tests. The
shear strength (MPa), cell viability (UFC / mL) and microhardness (HV) data were analyzed
statistically by ANOVA and Tukey's test (5%). The other tests were qualitative descriptive
analyzes. Results: The bond strength was affected by the in situ aging exposure for the LU
and VS materials (p = 0.0001), the highest bond strength for the diamond burs group + Single
Bond Universal (SUB) was observed in the LU (14.67MPa), for the VE the aged HF group
(17.10MPa) presented higher union strength, and the VS the HF group without aging
(14.27MPa) had higher union strength (p = 0.0001). The adhesive failure presented a higher
prevalence in all types of CAD/CAM block (LU: 78%, VE: 61%, VS: 98%). The Vita
Suprinity (734.31HV) exhibited the highest Vikers hardness and Lava Ultimate (137.34HV)
the lowest (p = 0.0001). Cell viability analysis showed no difference between fungal adhesion in the three materials (p = 0.9064). Regarding the analysis of the treated surfaces (SEM) and
roughness, it was observed that the blasting and diamond burs asperisation showed a greater
change in the surfaces of all the materials; the EDS analysis demonstrated that surface
treatments alter the surface chemical composition of the materials. Conclusion: In situ aging
changes the bond strength of LU and VS materials. The most effective surface treatment for
LU was diamond burs grinding + SBU, for VS and VS the conditioning with HF. The VS
presented greater Vickers hardness. The surface treatments promoted surface changes of
topography and roughness of all the materials tested, the largest roughness per material were
LU: COJET, VE: Al2O3 and VS: Diamond burs, besides altering the superficial chemical
composition in the materials. |
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