TY - BOOK AU - Aya Omar Tawfik Hussien AU - Eman Abou Auf , AU - Iman Elsayad , TI - The influence of acidic and/or abrasive challenge on the surface roughness of microfilled and nanohybrid flowable resin restorative materials : : An in vitro study / PY - 2017/// CY - Cairo : PB - Aya Omar Tawfik Hussien , KW - Acidic and/or abrasive challenge KW - Nanohybrid flowable resin restorative materials KW - The surface roughness N1 - Thesis (M.Sc.) - Cairo University - Faculty of Oral and Dental Medicine - Department of Operative Dentistry; Issued also as CD N2 - This study was conducted to investigate the effect of acidic and/ or mechanical challenge on the surface roughness of flowable resin composites. Ninety six resin composite discs were prepared according to manufactures instructions. The specimens were divided into two main groups of 48 specimens each, according to the type of flowable resincomposite used; nanohybrid flowable resin composite tetric N Flow (F₁), or microfilled flowable resin composite Heliomolar flow (F₂). Each group was further subdivided into four equal subgroups of 12 specimens each according to the type of challenge. First: the control group specimens were stored in artificial saliva at pH 7.4 (C₀). In the second group the specimens were subjected to an acidic challenge with orangejuice at pH 5 (C₁). For the third group the specimens were subjected to mechanical abrasion challenge by automatic tooth brushing (C₂). Finally, the specimens in forth group were subjected to an acidic challenge followed by mechanical abrasion challenge (C₃). Specimens of each group were examined for surface roughness at base line R0 and after exposure to the proposed challenge R₁. The change in the surface roughness values following application of different challenges were tested using USB digital microscope with a built-in camera, using fixed magnification of 120X. Results were collected, tabulated and statistically analyzed ER -