SHEREEN AHMED ABDELMAQSOUD NOSSAIR

Mona H Mandour

16/06/2023

https://www.sciencedirect.com/science/article/abs/pii/S0022391323003311

SHEREEN AHMED ABDELMAQSOUD NOSSAIR

Mona Hossam El-Din Mandour

05/06/2022

https://digitalcommons.aaru.edu.jo/cgi/viewcontent.cgi?article=1135&context=fdj

SHEREEN AHMED ABDELMAQSOUD NOSSAIR

01/07/2019

SHEREEN AHMED ABDELMAQSOUD NOSSAIR

01/07/2019

SHEREEN AHMED ABDELMAQSOUD NOSSAIR

Tarek Salah, Kamal Khaled Ebeid

01/03/2019

Objective: This study was designed to evaluate the biaxial flexural strength (BFS) of different types of unshaded and shaded monolithic zirconia. Material and Methods: 120 monolithic zirconia ceramic discs were fabricated. They were divided into twelve groups (n=10), Group 1; Bruxzir unshaded, Group 2; Bruxzir shaded A2, Group 3; Bruxzir anterior white, Group 4; Bruxzir anterior shade A2, Group 5; Prettau unshaded, Group 6; Prettau shaded with A2 coloring liquid, Group 7; Prettau anterior white, Group 8; Prettau anterior shaded with A2 coloring liquid, Group 9; Katana HT white, Group 10; Katana HT shade A2, Group 11; Katana ST white, Group 12; Katana ST shade A2. All discs were milled using a dental milling machine, and had final dimensions after sintering of 15 mm diameter and 1 mm thickness. BFS was tested using piston on three ball technique. Results: One-way ANOVA revealed significant differences among the 12 groups. Tukey post-hoc tests revealed no significant differences between the groups 3, 4, ,7 ,8 11, and 12. However, they all had BFS values that are significantly lower than all other groups. Group 2 showed statistically significant higher BFS values when compared to group 3,4, 7, 8, 11, and 12 while it showed statistically significant lower values when compared to groups 1, 5, 6, 9, and 10. Conclusion: Increase in the yttria content in zirconia led to a decrease in its BFS. Shading of zirconia did not have a significant effect on the final strength of zirconia.

SHEREEN AHMED ABDELMAQSOUD NOSSAIR

Tarek Salah

01/11/2018

Purpose: Establishing a reliable adhesive bond to zirconia-based materials is always a challenge. The purpose of this study was to evaluate the micro-shear bond strength of conventional and self-adhesive resin cements to zirconium oxide ceramic after different surface treatments. Material and Methods: Yttrium stabilized zirconia ceramic plates of dimensions 10 mm width × 10 mm length × 1 mm thickness were fabricated by a CAD/CAM process. The plates were divided into three groups according to surface treatments performed: (1) no treatment (NT); (2) airborne-particle abrasion with 110-μm alumina particles (SB); (3) silica coating with Cojet system (CT) (3M/ ESPE, USA). Each group was then divided into two subgroups according to type of resin cement; Panavia F 2.0 (Kurary, Japan) and RelyXUnicem (3M/ESPE, USA). Ten composite resin cylinders (0.75 - mm diameter × 0.5 - mm height) were bonded to each ceramic plate (N = 10), and each specimen was subjected to a shear load at a crosshead speed of 0.5 mm/min until fracture occurred. The fracture sites were examined with scanning electron microscopy (SEM) to detect the mode of failure. Data were statistically analyzed using two-way ANOVA and multiple comparisons were made using Fisher’s test at p < 0.05. Results: Micro-shear bond strength was significantly affected by the surface treatment and by the type of resin cement. Panavia F 2.0 showed higher significant results in comparison to RelyXUnicem. Surface treatment with CT was highly significant with both cements, followed by SB and then by NT. SEM examination revealed predominantly cohesive failures within the resin cements for CT group, mixed failures within SB group and predominantly adhesive failure at the interfacial area within NT group. Introduction The use of high-strength zirconium oxide ceramics for oral rehabilitation has grown in recent years. It has become a material of choice for esthetic restorations, because of its unique properties and biocompatibility. CAD/CAM technology has simplified the fabrication of zirconia restorations. Additionally, adhesively bonded zirconia restorations, have recently surfaced as a conservative treatment option for minimally invasive approaches. They depend entirely on resin adhesive cementation for retention, marginal adaptation and resistance against masticatory loads [1-7]. Surface treatment is essential for bonding to ceramics. However, zirconia is resistant to hydrofluoric acid etching because of its crystallinity and the limited glassy phase (below 1%) [7-11]. As a consequence, other conditioning methods have been suggested. Airborne abrasion was reported by many studies to be an effective way of increasing the surface area and producing a degree of roughness that can lead to an acceptable resin/ceramic micromechanical interlocking [12,13]. Conclusions: The micro-shear bond strength of resin cement to partially stabilized zirconia ceramics varied significantly depending on the type of resin luting agent and surface treatment method. The tribochemical silica coating of zirconia surfaces in combination with MDP-containing resin cement (Panavia F 2.0) showed a superior performance.

SHEREEN AHMED ABDELMAQSOUD NOSSAIR

Kamal Ebeid, Tarek Salah

01/09/2017

Purpose of Review The aim was to compare the accuracy of digital intraoral impressions with conventional impressions on the fabrication of different types of restorations. This study also compared the accuracy, reliability, and ease of use of different types of intraoral scanners available and correlated the results with the different scanning technologies. Recent Findings Digital impressions offer the same level of accuracy as conventional impressions regarding fabrication of crowns, fixed dental prostheses (FDPs), implant-supported crowns, and short-span FDPs with marginal gap values within the clinically acceptable range (<120 μm). However, for full-arch restorations, conventional impressions result in better accuracy. Summary Further enhancements needs to be undertaken regarding intraoral scanners to improve its accuracy regarding fabrication of full-arch restorations. Further in vivo studies evaluating the accuracy of intraoral digital impressions on the fabrication of a wider range of restorations such as inlays, veneers, and full-arch restoration need to be conducted.

SHEREEN AHMED ABDELMAQSOUD NOSSAIR

Moustafa N. Aboushelib, Tarek Salah Morsi

01/10/2015