MARC details
| 000 -LEADER |
|---|
| fixed length control field |
13470ntm a22002537a 4500 |
| 008 - FIXED-LENGTH DATA ELEMENTS--GENERAL INFORMATION |
|---|
| fixed length control field |
201217b2015 a|||f mb|| 00| 0 eng d |
| 040 ## - CATALOGING SOURCE |
|---|
| Original cataloging agency |
EG-CaNU |
| Transcribing agency |
EG-CaNU |
| 041 0# - Language Code |
|---|
| Language code of text |
eng |
| Language code of abstract |
eng |
| -- |
ara |
| 082 ## - DEWEY DECIMAL CLASSIFICATION NUMBER |
|---|
| Classification number |
620 |
| 100 0# - MAIN ENTRY--PERSONAL NAME |
|---|
| Personal name |
Omnia Mahmoud Abdel Ghaney |
| 245 1# - TITLE STATEMENT |
|---|
| Title |
Improving Nanosized -Anatase Photocatase photocatalytic Activity for Dental Bleaching Application |
| Statement of responsibility, etc. |
Omnia Mahmoud Abdel Ghaney |
| 260 ## - PUBLICATION, DISTRIBUTION, ETC. |
|---|
| Date of publication, distribution, etc. |
2015 |
| 300 ## - PHYSICAL DESCRIPTION |
|---|
| Extent |
p. |
| Other physical details |
ill. |
| Dimensions |
21 cm. |
| 500 ## - GENERAL NOTE |
|---|
| Materials specified |
Supervisor: Mostafa El Ashry |
| 502 ## - Dissertation Note |
|---|
| Dissertation type |
Thesis (M.A.)—Nile University, Egypt, 2015 . |
| 504 ## - Bibliography |
|---|
| Bibliography |
"Includes bibliographical references" |
| 505 0# - Contents |
|---|
| Formatted contents note |
Contents:<br/>CHAPTER II: Background and Literature Review ....................................................... 5<br/>1. Teeth discoloration.............................................................................................. 5<br/>1.1 Intrinsic discoloration .................................................................................. 5<br/>1.2 Internalized discoloration ............................................................................ 5<br/>1.3 Extrinsic discoloration ................................................................................. 5<br/>1.3.1 Direct stains ............................................................................................. 6<br/>1.3.2 Indirect stains ........................................................................................... 6<br/>2. Historical background ......................................................................................... 6<br/>3. Mechanisms of peroxide dental bleaching .......................................................... 8<br/>4. Types of dental bleaching ................................................................................. 12<br/>5. In-Office dental bleaching ................................................................................ 12<br/>Efficacy ................................................................................................................ 13<br/>Side effects ........................................................................................................... 14<br/>6. Assisted dental bleaching .................................................................................. 15<br/>6.1 Heat-activated ............................................................................................ 15<br/>6.2 Light-activated ........................................................................................... 16<br/>6.3 Photo-catalyst activated ................................................................................. 17<br/>7. Titania as a photo-catalyst ................................................................................ 18<br/>7.1 Methods of synthesis ................................................................................. 20<br/>7.2 Mechanism of Titania photo-catalysis ....................................................... 21<br/>8. Modifications of Titania ................................................................................... 24<br/>8.1 Non-metal Modification of Titania............................................................ 24<br/>8.2 Heterojunctions .......................................................................................... 26<br/>8.3 Metallic modification of Titania ................................................................ 26<br/>8.4 Modification with Noble metal nano-particles .......................................... 27<br/>8.4.1 Silver addition ........................................................................................ 29<br/>8.4.2 Gold addition ......................................................................................... 31<br/>CHAPTER III: METHODOLOGY ............................................................................. 33<br/>1. Preparation ........................................................................................................ 34<br/>1.1 Fabrication ................................................................................................. 34<br/>ix<br/>The Chemicals ..................................................................................................... 35<br/>1.1.1. Nanosized-anatase preparation (T) ........................................................ 35<br/>1.1.2. Method 1 (M1) noble metal addition (TS, TG preparation) .................. 36<br/>1.1.3. Method 2 (M2) noble metal addition (TSnp, TGnp Preparation) .......... 36<br/>Silver nano-particles preparation (Snp) ............................................................... 37<br/>Gold nano-particles preparation (Gnp) ................................................................ 37<br/>1.2. Characterization ......................................................................................... 37<br/>1.2.1. X-Ray Diffraction (XRD) ...................................................................... 38<br/>1.2.2. Transmission Electron Microscope (TEM) ........................................... 39<br/>1.2.3. UV-Vis Spectrophotometer ................................................................... 40<br/>2. Testing............................................................................................................... 41<br/>2.1. Experimental Solutions preparation .......................................................... 42<br/>2.2. Glassware................................................................................................... 43<br/>2.3. Equipment .................................................................................................. 44<br/>2.3.1. Activating light ...................................................................................... 44<br/>2.3.2. Vis-NIR Spectrophotometer .................................................................. 45<br/>2.4. Experimental set-up ................................................................................... 46<br/>2.5. The experiment .......................................................................................... 47<br/>CHAPTER IV: RESULTS AND DISCUSSION ........................................................ 48<br/>1. Results of the preparation phase ....................................................................... 48<br/>1.1. Titania ........................................................................................................ 48<br/>Transmission electron microscope (TEM)........................................................... 48<br/>UV-Vis spectrophotometer .................................................................................. 49<br/>X-ray diffraction (XRD) ...................................................................................... 50<br/>1.2. Method 1 (M1) noble metal addition ......................................................... 51<br/>1.2.1. Titania silver (TSO) ............................................................................... 51<br/>TEM ..................................................................................................................... 51<br/>UV-Vis spectrophotometer .................................................................................. 52<br/>XRD ..................................................................................................................... 52<br/>1.2.2. Titania gold (TG) ................................................................................... 53<br/>TEM ..................................................................................................................... 53<br/>UV-Vis spectrophotometer .................................................................................. 53<br/>XRD ..................................................................................................................... 54<br/>1.3. Method 2 noble metal addition .................................................................. 55<br/>Silver nano-particles (Snp) .................................................................................. 55<br/>Gold nano-particles (Gnp) ................................................................................... 55<br/>1.3.1. Titania + Silver nano-particles (TSnp) .................................................. 56<br/>TEM ..................................................................................................................... 56<br/>UV-Vis spectroscope ........................................................................................... 57<br/>1.3.2. Titania + gold nano-particles (TGnp) .................................................... 57<br/>TEM ..................................................................................................................... 57<br/>UV-Vis spectroscope ........................................................................................... 58<br/>2. Results of the testing phase ............................................................................... 59<br/>2.1. Pilot study: Effect of Titania photocatalyst on the bleaching process of MB dye (T vs controls) ............................................................................................... 59<br/>UV group ............................................................................................................. 60<br/>Vis light group ..................................................................................................... 61<br/>UV vs Vis ............................................................................................................. 63<br/>2.2. Effect of noble metal addition Method 1(T vs M1) ................................... 64<br/>UV group ............................................................................................................. 64<br/>x<br/>Vis group .............................................................................................................. 66<br/>UV vs Vis ............................................................................................................. 67<br/>2.3. Effect of noble metal addition Method 2 (T vs M2) .................................. 68<br/>UV group ............................................................................................................. 68<br/>Vis group .............................................................................................................. 70<br/>UV vs Vis ............................................................................................................. 71<br/>3. Data analysis ..................................................................................................... 72<br/>3.1. Effect of photocatalyst addition ................................................................. 72<br/>3.2. The effect of addition method on the photosensitivity and photocatalytic activity of Titania (M1 vs M2)............................................................................. 73<br/>3.2.1 M1 vs M2 with Silver ............................................................................ 74<br/>3.2.2 M1 vs M2 with Gold .............................................................................. 75<br/>3.3. Best performance ....................................................................................... 76<br/>CHAPTER V: CONCLUSION.................................................................................... 78<br/>REFERENCES ............................................................................................................ 80<br/>Appendix A .................................................................................................................. |
| 520 3# - Abstract |
|---|
| Abstract |
Abstract:<br/>In-office dental bleaching is a popular treatment for restoring and improving teeth color. In-office bleaching products contain high concentrations of hydrogen peroxide (up to 40%), which can be damaging to teeth. Nanosized-anatase photocatalysts (T) were used to enhance the activity of bleaching products using lower concentrations of hydrogen peroxide (H). However, T requires activation by ultraviolet (UV) radiation, which can be harmful to patients. In the present study, we aimed to improve the photocatalytic activity and photosensitivity (to Vis light) of T used for dental bleaching by gold and silver addition. Improvement was evaluated via the photo-degradation of methylene blue dye (MB) in H solution of 3.5% under UV radiation and under Vis light source. T was prepared using sol-gel method and a pilot study was done to assess its activity in both UV and Vis light. T modification with gold (G) and silver (S) was done using two methods (M1, and M2). M1: was done by adding gold and silver precursors to T during preparation making (TS, and TG). M2: was done by preparing gold and silver nanoparticles (Gnp, and Snp) separately and mix them with T freshly in the experimental solution forming (TGnp, and TSnp). The experiment was done by exposing the experimental solutions to activating light for 10 min and measuring the photo-degradation\min of MB using Vis-NIR spectrophotometer. The results showed an improvement in photocatalytic activity and photosensitivity of all samples especially with TSnp, which yielded the best performance in Vis light. We concluded that G and S addition did improve both the photocatalytic activity and photosensitivity of T highlighting the TSnp as a strong candidate for Vis light assisted in-office dental bleaching. |
| 546 ## - Language Note |
|---|
| Language Note |
Text in English, abstracts in English and Arabic |
| 650 #4 - Subject |
|---|
| Subject |
Nano- Science & Technology |
| 655 #7 - Index Term-Genre/Form |
|---|
| Source of term |
NULIB |
| focus term |
Dissertation, Academic |
| 690 ## - Subject |
|---|
| School |
Nano- Science & Technology |
| 942 ## - ADDED ENTRY ELEMENTS (KOHA) |
|---|
| Source of classification or shelving scheme |
Dewey Decimal Classification |
| Koha item type |
Thesis |
| 650 #4 - Subject |
|---|
| -- |
199 |
| 655 #7 - Index Term-Genre/Form |
|---|
| -- |
187 |
| 690 ## - Subject |
|---|
| -- |
199 |