Mohamed ahmed Wakwak
@azucdent.net
Alazhar univerisity
Alazhar univerisity
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Aeshah Hassan Abduljabar, Ahmad Waleed Iskander, Mohamed Taha Elfezary, Mohamed AboElkasem Ahmed Wakwak, Wafa Abdullah Bathabt, and Yasser R. Souror
Georg Thieme Verlag KG
Abstract Objective To study the possibility of using pediatric endocrowns to restore the second primary molar using three-dimensional (3D) finite element analysis. Design A 3D finite element model was built for a pediatric mandibular molar, starting with laser scanning a naturally extracted tooth. The access cavity had an elliptic shape with 6 mm width, 4 mm height, and 2 mm depth with a wall taper angle of 5 degrees.Two materials (Zr and E-max) were tested for the endocrown and two cementing materials (glass ionomer and resin cement) with 20 to 40 μm thickness. Twelve case studies were reported within this research as the applied load of 330 N was tested with three angulations vertical, oblique at 45 degrees, and laterally. Results Twelve linear static stress analyses were performed. The resultant stresses and deformations' distribution patterns did not alter much, and values were within the threshold of physiological tolerance. Deformations were negligibly changed with changing endocrown and cement materials. In contrast, endocrown stresses indicated zirconia endocrown would have a long lifetime, while E-max one will have a relatively short lifetime. Conclusions Analysis results indicated that bone was negligibly affected by changing endocrowns and cementing materials. Both tested endocrown materials can be used safely. Zirconia endocrowns may have a much longer lifetime than E-max.
Amr Mohsen Mohamed, Sameh Mahoud Nabih, and Mohamed Ahmed Wakwak
Editora Cubo
Objective: The purpose of this study was to evaluate the effect of chitosan nanoparticles on microtensile bond strength of resin composite to dentin using self etch adhesive after aging. Material and Methods: A total number of 90 freshly extracted, sound human molar teeth. Flat tooth surface was gained after cut of the occlusal surface. Three main groups according to pretreatment of dentin before adhesive application; 0.2 % chitosan, 2.5 % chitosan and no treatment control group. Universal self etch adhesive were applied according to manufacture instruction and 4 mm of Feltik Z250 xt composite. Storage of specimens for 1 day, 3 months and 6 months in 37O C distilled water. After that, the tooth was sectioned to beams of 1 mm x8 mm sticks for microtensile bond strength test using universal testing machine. Scanning electron microscope (SEM) was used to evalute the effect of chitosan nanoparticles on dentin and smear layer. Kruskal-Wallis test was used to compare between the three groups as well as the three aging periods. Dunn’s test was used for pair-wise comparisons. The significance level was set at P ? 0.05. Results: chitosan 0.2% is statistically significant increase in bond strength than chitosan 2.5% and control in one day group. Three months chitosan 0.2 % groups have statistically significant increase in bond strength than chitosan 2.5%. It was found in 6 months that control and chitosan 0.2 % have statistically significant increase in bond strength than chitosan 2.5%. There was statistically significant difference found between the three studied groups regarding bond strength at different storage times . Conclusion: Microtensile bond strength was influenced by different chitosan concentration. Different aging periods had no effect on the microtensile bond strength without application of chitosan and with application of 2.5% chitosan concentration.KEYWORDSChitosan nanoparticles; Microtensile bond strength; MMPs.
Mohamed Ahmed Wakwak, Eslam Hassan Gabr, and Ahmed Mohamed Elmarakby
Scientific Foundation SPIROSKI
BACKGROUND: The durability of dentin-resin interfaces with the universal adhesive system is a crucial characteristic with chemical interactions between the exposed collagen and the adhesive monomers, but it is still compromised with wet and dry mode.
 AIM: The present study evaluated the effect of dentin wetness and solvents containing of one-step self-etch adhesives on the microtensile bond strength (μTBS) of dentin at different storage times.
 METHODS: Occlusal dentin of 54 extracted human molars was exposed. Each adhesive agent was applied according to manufacturer instructions to wet and dry dentin surfaces. Composite resin was incrementally built up. Bond strengths to dentin were determined using the μTBS test after water storage for 24 h, 1 month, and 6 months. One-way ANOVA was used to compare between more than two non-related samples. The significance level was set at p ≤ 0.05.
 RESULTS: Dryness of dentin increases the μTBS with solvent-containing adhesives while decrease the μTBS with solvent-free adhesive. There was an increase in microtensile bond strength values in the case of ethanol water-based self-etch adhesive over time. No statistically significant difference was found among different storage times regarding μTBS for solvent-free adhesive, while a statistically significant difference was found among different storage times in μTBS for solvent-containing adhesives.
 CONCLUSION: Universal adhesive systems improve the durability and stability of dentin bond strength.