scholarly journals The influence of the resin‐based cement layer on ceramic‐dentin bond strength

Author(s):  
Mina Aker Sagen ◽  
Jon Einar Dahl ◽  
Jukka Pekka Matinlinna ◽  
John E. Tibballs ◽  
Hans Jacob Rønold
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2016 ◽  
Vol 27 (5) ◽  
pp. 592-598 ◽  
Author(s):  
Regina Maria Helen-Cot Marcos ◽  
◽  
Gustavo Ross Kinder ◽  
Edson Alfredo ◽  
Tarcisio Quaranta ◽  
...  

Abstract The objective of the present study was to evaluate the influence of resin cement thickness on the bond strength of prefabricated and customized glass fiber posts after storage in distilled water. Thirty human uniradicular roots were treated endodontically. The roots were divided into 3 groups: THIN (thin cement layer) - post space preparation with #0.5 drill and cementation of #0.5 post; THICK (thick cement layer) - post space preparation with #1 drill and cementation of #0.5 post; and CUSTOM (customized cement layer) - post space preparation with #1 drill and cementation of a customized post (#0.5 glass fiber posts customized with resin composite). All posts were luted with self-adhesive resin cement. The push-out test was carried out after storage for 24 h and 90 days in distilled water at 37 °C. The data were analyzed with three-way ANOVA and Tukey's test (a=0.05). Bond strengths were significantly higher for CUSTOM (9.37 MPa), than for THIN (7.85 MPa) and THICK (7.07 MPa), which were statistically similar. Considering the thirds, the bond strength varied in the sequence: apical (7.13 MPa) < middle (8.22 MPa) = coronal (8.94 MPa). Bond strength for 24 h storage was significantly higher (8.80 MPa) than for 90-day storage (7.40 MPa). It may be concluded that the thickness of resin cement influenced the bond strength of glass fiber posts. The customized posts presented higher bond strength. Storage in water for 90 days affected negatively the values of bond strength, especially for thick cement layers in the apical third.


Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5153
Author(s):  
João Paulo Mendes Tribst ◽  
Alison Flavio Campos dos Santos ◽  
Giuliane da Cruz Santos ◽  
Larissa Sandy da Silva Leite ◽  
Julio Chávez Lozada ◽  
...  

This study tested whether three different cement layer thicknesses (60, 120 and 180 μm) would provide the same bonding capacity between adhesively luted lithium disilicate and human dentin. Ceramic blocks were cut to 20 blocks with a low-speed diamond saw under cooling water and were then cemented to human flat dentin with an adhesive protocol. The assembly was sectioned into 1 mm2 cross-section beams composed of ceramic/cement/dentin. Cement layer thickness was measured, and three groups were formed. Half of the samples were immediately tested to evaluate the short-term bond strength and the other half were submitted to an aging simulation. The microtensile test was performed in a universal testing machine, and the bond strength (MPa) was calculated. The fractured specimens were examined under stereomicroscopy. Applying the finite element method, the residual stress of polymerization shrinkage according to cement layer thickness was also calculated using first principal stress as analysis criteria. Kruskal–Wallis tests showed that the ‘‘cement layer thickness’’ factor significantly influenced the bond strength results for the aged samples (p = 0.028); however, no statistically significant difference was found between the immediately tested groups (p = 0.569). The higher the cement layer thickness, the higher the residual stress generated at the adhesive interface due to cement polymerization shrinkage. In conclusion, the cement layer thickness does not affect the immediate bond strength in lithium disilicate restorations; however, thinner cement layers are most stable in the short term, showing constant bond strength and lower residual stress.


Author(s):  
J. E. Lai-Fook

Dermal glands are epidermal derivatives which are reported to secrete either the cement layer, which is the outermost layer of the epicuticle or some component of the moulting fluid which digests the endocuticle. The secretions do not show well-defined staining reactions and therefore they have not been positively identified. This has contributed to another difficulty, namely, that of determining the time of secretory activity. This description of the fine structure of the developing glands in Rhodnius was undertaken to determine the time of activity, with a view to investigating their function.


Author(s):  
Shubham N. Dadgal ◽  
Shrikant Solanke

In modern days for structures in coastal areas it has been observed that the premature structural failures are occurs due to corrosion of the reinforcements of the designed structural member. The corrosion causes the structural damage which in turn leads to reduction in the bearing capacity of the concerned structural members. The aim of this study was to study the effect of partial replacement of fly ash to minimize the corrosion effect. Beams were designed and corroded by using artificial method known accelerated corrosion method. The beams were then tested for flexural and bond strength. Also the weight loss of the reinforced bars was been determined using electrical resistivity method. The fly ash will replace by 10% and 15%.The strength will calculate at varying percentage of corrosion at 10% and 15%. Beams will cast at M25 grade concrete. The flexural strength will test by using UTM and the bond strength will calculate using pullout test.


2019 ◽  
Vol 68 (5) ◽  
Author(s):  
Eloisa H. Aranda Garcia de Souza ◽  
Sandrine B. Berger ◽  
Eloisa A. Carlesse Paloco ◽  
Rodrigo V. Caixeta ◽  
Thais S. Moretto ◽  
...  
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2020 ◽  
Vol 69 (3) ◽  
Author(s):  
Felipe Sczepanski ◽  
Cláudia R. Brunnquell ◽  
Sandrine B. Berger ◽  
Eloisa A. Paloco ◽  
Murilo B. Lopes ◽  
...  

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