Biaxial flexural strength of Bi-layered Poly Ether Ether Ketone restorations using different thickness Ratios between PEEK core and different veneering materials before and after aging : (In-Vitro Study) / By Ahmed Farouk Gouda ; Supervisors Prof. Dr. Ashraf Hussein Sherif, Prof. Dr. Tarek Salah El-Din Morsi, Dr. Mennatallah Mohie el-Din Wahba Aly el-Din

Thesis (M.Sc.)-. Future University in Egypt, Faculty of Oral and Dental Medicine, Department Fixed Prosthodontics, 2022.

Includes bibliographical references.

Bio High Performance Polymer (BioHPP) is partially crystalline, thermoplastic polymer has been developed as a PEEK variant that has been especially optimised for the dental field. BioHPP is as close as possible to the bone in terms of its coefficient of elasticity (4 GPa), thus the risk of fracture is reduced(15). Its use as a monolithic restoration is still limited because of its high opacity, grayish to white color and low translucency compared to dental ceramics. Thus, additional veneering is considered indispensable. A total of ninety specimens were divided into three main groups according to their veneering material. • Group A: BioHPP discs veneered with IPS e.max CAD (n=30) • Group B: BioHPP discs veneered with HIPC CAD (n=30) • Group C: BioHPP discs veneered with crea.lign resin composite (n=30) The required shape of the specimens was designed using digital software system in order to accurately design a disc shape (12mm diameter×0.5, 0.7, 0.8 and 1mm thickness) from the BioHPP and HIPC blanks (98mm diameter×25 mm thickness). Isomet was used to cut thirty discs from their respective cylinder of IpS emax with dimensions (12 mm diameter × 0.5, 0.8 and 1mm thickness). Then Each BioHPP disc was veneered with its corresponding thickness of the esthetic materials disc, finished and polished according to manufacturer instructions. Half of the specimens of each subgroup were tested for bi-axial flexural strength using universal testing machine and half of the specimens in each subgroup were subjected to artificial aging through thermocycling furnace. One specimen of each group was examined using SEM before and after aging to examine the fracture surface of specimens. The results of biaxial flexural strength revealed that thickness ratio (regardless of material and aging) had a statistically significant effect on mean biaxial flexural strength (P-value <0.001, Effect size = 0.51). Aging (regardless of material and thickness ratio) also had a statistically significant effect on mean biaxial flexural strength (P-value <0.001, Effect size = 0.856). Regardless of thickness ratio and aging; there was a statistically significant difference between materials (P-value <0.001, Effect size = 0.83). Pair-wise comparisons between materials revealed that Crea.lign showed the statistically significantly highest mean biaxial flexural strength. HIPC CAD showed statistically significantly lower mean biaxial flexural strength. IPS e.max CAD showed the statistically significantly lowest mean biaxial flexural strength.

Text in English, Abstract in English and Arabic.