الفهرس 
REVIEW OF LITERATUREOnly 14 pages are availabe for public view
 |  | from | 133 |  |  |
| | | from | 133 | | |
Abstract
The demand for treating un-esthetic anterior teeth continues to grow. The available options to restore their esthetics include conservative treatments as bleaching, micro-abrasion and laminate veneers restorations. Nowadays, the laminate veneers become an important part of smile designing. The main advantage of using a laminate veneer is conservation of tooth structure and as much as we can go thinner as much as the tooth structure will be conserved. The clinical success of laminate veneers depends on their marginal fit to prevent exposing of the cement, staining and discoloration. So proper selection of the material that can fulfill that need is a must especially when the veneers are in thin thickness.
Lithium disilicate glass ceramic is claimed to be the material of choice in such cases.
Lithium disilicate ceramic materials are available by many manufacturers.
The aim of our study was to evaluate the marginal fit of laminate veneers made from different lithium disilicate ceramic material (IPS e.max blocks, Upcera blocks and Rosetta® SM blocks) at two thicknesses 0.3mm and 0.7mm using CAD/CAM milling machine (Sirona Cerec MCXL).
In our study, we prepared two acrylic central incisors. One with preparation depth 0.3mm and another was with 0.7mm preparation depth. Impression was made for each tooth for duplication of epoxy resin dies. CEREC Omnicam intraoral scanner (Dentsply Sirona product) was used to scan the model, restorations were designed on Cerec Premium 4.4.4 software then milling using Cerec MCXL milling machine. Each veneer was cemented to its corresponding die after hydrofluoric etching and silanation using light cured veneer cement.
Digital microscope was used to capture the 4 surfaces of the teeth restoration interface. Image J software was used to measure this gap. In each surface, 5 points were taken and the mean per surfaces and per each tooth marginal gap was calculated.
The results showed that:
1. IPS e.max showed significantly higher marginal gap value than other materials only cervically.
2. UpCad Upcera showed significantly higher marginal gap value than IPS e.max and Rosetta SM only in proximal 1 surfaces.
3. For all other surfaces, and the total avarages for each sample group, the difference was not statistically significant between the three marterials.
4. For all surfaces, there was no significant difference between samples with different thicknesses.
5. The whole samples laid within the clinically accepted marginal gap less than 108µm.
CONCLUSION
Within the limitations of this in vitro study, the following conclusions were drawn:
• The overall marginal gap of laminates fabricated from IPS e.max, Upcera and Rosetta SM lithium disilicate CAD blocks is comparable to each other and is considered to be clinically acceptable.
• Changing thicknesses of lithium disilicate laminate veneers didn’t affect restoration marginal adaptation.