الفهرس 
AcknowledgmentsOnly 14 pages are availabe for public view
 |  | from | 125 |  |  |
| | | from | 125 | | |
Abstract
This study was designed to assess the effect of acidity on the fluoride release, uptake, recharging and surface roughness of three different glass ionomer based restoration. Material and methods: For the fluoride release and surface roughness tests a total of 45 specimens were prepared, they were divided in to three equal groups; where (R1) represents (Ketac Fill), (R2) represents (Ketac N100) and (R3) (Beautifil П). Specimens of each group were divided into three subgroups; the specimens of the subgroup (M1) were always kept immersed in the artificial at pH 7, the specimens of the others two subgroups were exposed to pH cycling between the artificial saliva at pH 7 and acetic acid at pH 5.5 (M2) or citric acid at pH 4 (M3). For each group, the cumulative amount of the released fluoride and surface roughness was assessed at one week (P1), 4 weeks (P2) and 12 weeks (P3). Teflon mold was used, and different materials were applied according to the manufacturer’s instructions, the fluoride release was recorded with the use of an ion specific electrode, while surface roughness was carried out using (QESEM) was used, While for the fluoride uptake and recharging a total of 180 molar were collected. Class V cavities were prepared on the buccal surfaces. The restorative materials were applied according to manufacturer’s instruction. The fluoride uptake analysis was carried out using (EDAX) of the QESEM. Results: revealed (Ketac N100) showed a highest fluoride release, while (Ketac Fil) showed highest mean surface Roughness and fluoride uptake. Conclusions: 1) Exposure to acidic media has a great impact on fluoride release, uptake and surface roughness properties of tested restorative materials. 2) No relation is evident between cumulative amount of fluoride release, surface roughness of the restorative material and fluoride uptake by human dentin. 3) Under acidic condition still sealing ability of the material the most important factor affecting the dentin fluoride uptake. 4) Enhanced fluoride release doesn’t unequivocally indicate increased fluoride uptake. 5) Topical fluoride application didn’t enhance fluoride uptake by the tooth dentin. Keywords: glass ionomer, nanoionomer, giomer, fluoride release, uptake, surface roughness and pH cycling.