Microtomographic Analysis of Resin Composite Core Material Porosity

2020 ◽  
Vol 29 (7) ◽  
pp. 623-630
Author(s):  
Howard Roberts ◽  
Rodrigo Fuentealba ◽  
John Brewster
Keyword(s):  
Resin Composite ◽  
Core Material ◽  
Material Porosity

Endodontic Access Effect on Full Contour Zirconia and Lithium Disilicate Failure Resistance

2020 ◽  
Vol 45 (3) ◽  
pp. 276-285
Author(s):  
J Mallya ◽  
N DuVall ◽  
J Brewster ◽  
H Roberts
Keyword(s):  
Computer Aided Design ◽  
Failure Load ◽  
Fatigue Testing ◽  
Resin Composite ◽  
Glass Ionomer Cement ◽  
Surface Preparation ◽  
Lithium Disilicate ◽  
Load Resistance ◽  
Core Material ◽  
Computer Aided

SUMMARY Objectives: To evaluate the effect of endodontic access on the failure load resistance of both adhesively and conventionally luted, full-contour monolithic yttria-stabilized zirconium dioxide (Y-TZP) and adhesively luted lithium disilicate (LD) crowns cemented on prepared teeth. Methods and Materials: Seventy-two human maxillary molars were prepared per respective guidelines for all-ceramic crowns with one group (n=24) restored with LD and the other (n=48) receiving Y-TZP crowns. Preparations were scanned using computer-aided design/computer-aided milling (CAD/CAM) technology, and milled crowns were sintered following manufacturer recommendations. All LD crowns and half (n=24) of the Y-TZP crowns were adhesively cemented, while the remaining Y-TZP specimens were luted using a conventional glass ionomer cement (GIC). One LD group, one Y-TZP adhesive group, and one GIC-luted group (all n=12) then received endodontic access preparations by a board-certified endodontist: the pulp chambers were restored with a dual-cure, two-step, self-etch adhesive and a dual-cure resin composite core material. The access preparations were restored using a nano-hybrid resin composite after appropriate ceramic margin surface preparation. After 24 hours, all specimens were loaded axially until failure; mean failure loads were analyzed using Mann-Whitney U test (α=0.05) Results: Endodontic access did not significantly reduce the failure load of adhesively luted LD or Y-TZP crowns, but Y-TZP crowns with GIC cementation demonstrated significantly less failure load. Conclusions: These initial findings suggest that endodontic access preparation may not significantly affect failure load resistance of adhesively luted Y-TZP and LD crowns. Definitive recommendations cannot be proposed until fatigue testing and coronal seal evaluations have been accomplished.

Effect of different surface treatments of human occlusal sclerotic dentin on micro‐tensile bond strength to resin composite core material

2020 ◽  
Vol 128 (3) ◽  
pp. 263-273
Author(s):  
Anawat Kwansirikul ◽  
Daraporn Sae‐Lee ◽  
Onauma Angwaravong ◽  
Thidarat Angwarawong
Keyword(s):  
Bond Strength ◽  
Resin Composite ◽  
Surface Treatments ◽  
Tensile Bond Strength ◽  
Core Material

scholarly journals The Bond of Different Post Materials to a Resin Composite Cement and a Resin Composite Core Material

2012 ◽  
Vol 37 (6) ◽  
pp. E38-E49 ◽  
Author(s):  
D Stewardson ◽  
A Shortall ◽  
P Marquis
Keyword(s):  
Bond Strength ◽  
Chemical Interaction ◽  
Resin Composite ◽  
Resin Cement ◽  
Core Material ◽  
Composite Cement ◽  
Grit Blasting ◽  
Bond Strengths ◽  
Push Out ◽  
Resin Composite Cement

SUMMARY Purpose To investigate the bond of endodontic post materials, with and without grit blasting, to a resin composite cement and a core material using push-out bond strength tests. Materials and Methods Fiber-reinforced composite (FRC) posts containing carbon (C) or glass (A) fiber and a steel (S) post were cemented into cylinders of polymerized restorative composite without surface treatment (as controls) and after grit blasting for 8, 16, and 32 seconds. Additional steel post samples were sputter-coated with gold before cementation to prevent chemical interaction with the cement. Cylindrical composite cores were bonded to other samples. After sectioning into discs, bond strengths were determined using push-out testing. Profilometry and electron microscopy were used to assess the effect of grit blasting on surface topography. Results Mean (standard deviation) bond strength values (MPa) for untreated posts to resin cement were 8.41 (2.80) for C, 9.61(1.88) for A, and 19.90 (3.61) for S. Prolonged grit blasting increased bond strength for FRC posts but produced only a minimal increase for S. After 32 seconds, mean values were 20.65 (4.91) for C, 20.41 (2.93) for A, and 22.97 (2.87) for S. Gold-coated steel samples produced the lowest bond strength value, 7.84 (1.40). Mean bond strengths for untreated posts bonded to composite cores were 6.19 (0.95) for C, 13.22 (1.61) for A, and 8.82 (1.18) for S, and after 32 seconds of grit blasting the values were 17.30 (2.02) for C, 26.47 (3.09) for A, and 20.61 (2.67) for S. FRC materials recorded higher roughness values before and after grit blasting than S. With prolonged grit blasting, roughness increased for A and C, but not for S. Conclusions There was no evidence of significant bonding to untreated FRC posts, but significant bonding occurred between untreated steel posts and the resin cement. Increases in the roughness of FRC samples were material dependent and roughening significantly increased bond strength values (p<0.05). Surface roughening of the tested FRC posts is required for effective bonding.

Silicification of wood-cell walls

1994 ◽  
Vol 52 ◽  
pp. 428-429
Author(s):  
S. E. Keckler ◽  
D. M. Dabbs ◽  
N. Yao ◽  
I. A. Aksay
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Cell Walls ◽  
Lignin Content ◽  
Resin Composite ◽  
Middle Lamella ◽  
Cellulose Fibers ◽  
Complex Structures ◽  
Rich Region ◽  
Inorganic Precursors

Cellular organic structures such as wood can be used as scaffolds for the synthesis of complex structures of organic/ceramic nanocomposites. The wood cell is a fiber-reinforced resin composite of cellulose fibers in a lignin matrix. A single cell wall, containing several layers of different fiber orientations and lignin content, is separated from its neighboring wall by the middle lamella, a lignin-rich region. In order to achieve total mineralization, deposition on and in the cell wall must be achieved. Geological fossilization of wood occurs as permineralization (filling the void spaces with mineral) and petrifaction (mineralizing the cell wall as the organic component decays) through infiltration of wood with inorganics after growth. Conversely, living plants can incorporate inorganics into their cells and in some cases into the cell walls during growth. In a recent study, we mimicked geological fossilization by infiltrating inorganic precursors into wood cells in order to enhance the properties of wood. In the current work, we use electron microscopy to examine the structure of silica formed in the cell walls after infiltration of tetraethoxysilane (TEOS).

Postoperative sensitivity associated with resin composite restorations

ORL ro ◽  
2018 ◽  
Vol 4 (41) ◽  
pp. 45
Author(s):  
Irina-Maria Gheorghiu ◽  
Loredana Mitran ◽  
Mihai Mitran ◽  
Anca-Nicoleta Temelcea ◽  
Sânziana Scărlătescu ◽  
...  
Keyword(s):  
Resin Composite ◽  
Composite Restorations ◽  
Postoperative Sensitivity

Flexural Resistance of Steel-Coconut Shell Concrete-Steel Composite Beam with Normal and J-Hook Shear Studs

2020 ◽  
Vol 12 (9) ◽  
Author(s):  
Lakshmi Thangasamy ◽  
◽  
Gunasekaran Kandasamy ◽  
Keyword(s):  
Concrete Strength ◽  
Steel Plates ◽  
Coconut Shell ◽  
Core Material ◽  
River Sand ◽  
Concrete Core ◽  
Conventional Concrete ◽  
Moment Capacity ◽  
The Moment ◽  
Core Concrete

Many researches on double skin sandwich having top and bottom steel plates and in between concrete core called as steel-concrete-steel (SCS) were carried out by them on this SCS type using with different materials. Yet, use of coconut shell concrete (CSC) as a core material on this SCS form construction and their results are very limited. Study investigated to use j-hook shear studs under flexure in the concept of steel-concrete-steel (SCS) in which the core concrete was CSC. To compare the results of CSC, the conventional concrete (CC) was also considered. To study the effect of quarry dust (QD) in its place of river sand (RS) was also taken. Hence four different mixes two without QD and two with QD both in CC and CSC was considered. The problem statement is to examine about partial and fully composite, moment capacity, deflection and ductility properties of CSC used SCS form of construction. Core concrete strength and the j-hook shear studs used are influences the moment carrying capacity of the SCS beams. Use of QD in its place of RS enhances the strength of concrete produced. Deflections predicted theoretically were compared with experimental results. The SCS beams showed good ductility behavior.

The Flow Behavior of Core Material and Breakthrough Phenomenon in Sandwich Injection Molding

2003 ◽  
Vol 18 (4) ◽  
pp. 405-411 ◽  
Author(s):  
D. Watanabe ◽  
U. S. Ishiaku ◽  
T. Nagaoka ◽  
K. Tomari ◽  
H. Hamada
Keyword(s):  
Injection Molding ◽  
Flow Behavior ◽  
Core Material
Sign in / Sign up

Export Citation Format

Share Document