الفهرس | Only 14 pages are availabe for public view |
Abstract Less application steps, reduce manipulation time and technique sensitivity, and may so improve bonding effectiveness in routine clinical practice. Universal adhesives were recently introduced. This study was conducted to evaluate micro shear bond strength, resin /dentin interface and nanoleakage of newly introduced different multi-mode adhesives on dentin. A total of 180 anterior bovine teeth were extracted from sacrificed bovine jaws. The labial surface of the cervical half was ground flat to remove enamel and expose an area of nearly 8mm diameter of dentin using 600 grit sand papers. The specimens were divided into thirty groups (n=6) according to the three levels of the study; Level 1: adhesive system (Peak U, G-aenial B, Futura U, Single Bond U and All Bond U). Level 2: application mode (self etching, etch and rinse dry bonding and etch and rinse wet bonding) Level 3: storage period (24 hours and one year). All the specimens will be subjected to micro shear bond strength testing using Universal Testing Machine. Another total of 120 bovine teeth of each previous experimental group n=4 were prepared and used for evaluation of the resin/dentin interface and naoleakage. Results of micro shear bond strength testing showed that adhesive systems and storage periods had a significant effect on the micro shear bond strength to bovine dentin (P=0.0001). On the other hand, application modes had no significant effect on the micro shear bond strength to bovine dentin (p=0.144). Evaluation of SEM micrographs of resin/dentin interfaces bonded with different universal adhesives supported the bond strength data. 108 Conclusions: Under the limitations of this study, the following conclusions could be drawn: 1- Bond strength of multi mode adhesives is affected by the adhesive composition and acidity. 2- The effect of application mode on bond strength is insignificant, regardless to other factors. However, the interaction of adhesive type, mode of application and storage time is highly significant. 3- Durability of bond strength is affected by adhesive type. 4- Application of etching step prior to multi mode adhesives improves their resin/dentin penetration pattern. 5- Nanoleakage is dependent on the interaction between adhesive composition, application mode and storage period. Recommendations: 1- Further studies on different substrates, such as carious dentin in association with in vivo tests are needed to assess the long term clinical behavior of new multi mode adhesives. 2- Further evaluating tests, such as water sorption, solubility and degree of conversion are recommended to correlate between adhesives performance over different storage periods. 109 |