Abstract
Aim: The in vitro study evaluated the effect of different concentrations of green tea extract solution (GT) on the bonding durability of etch-and-rinse adhesive system to caries dentin affected (CAD). Methods: Dentinal surfaces of human third molars were polished and submitted to a microbiological caries induction protocol for 14 days. After removal of the infected dentin layer, the samples were randomly divided into 4 groups (n= 10), according to the concentration of GT solution applied in CAD, after acid etching: 0.05%; 0.2%; 2% and NT (no treatment – control). After application of a etch-and-rinse adhesive system (Adper Single Bond 2, 3M ESPE), composite resin restorations were performed on the dentin. After 24 hours, the resin-dentin blocks were sectioned 1mm2 specimens, which were subjected to the microtensile test immediately or after 6 months of storage in water. Data were submitted to two-way ANOVA for randomized blocks and Tukey test (α= 5%). Results: There was no effect of double interaction (p= 0.934). The application of 0.2% GT promoted a statistically significant increase in dentin bond strength values in comparison to the condition where GT was not used (p=0.012). There was a significant decrease of bond strength after 6 months of storage, regardless of dentin pretreatment (p = 0.007). The G test identified that there was no statistical difference regarding failure mode (p= 0.326). Conclusion: The concentration of 0.2% improved the bond strength of an etch-and-rinse adhesive system to caries affected dentin, however, none of dentin pretreatments could prevent the decrease in bond strength over time.
Highlights
The longevity of adhesive restorations is directly related to the durability of the bond between adhesive systems and dental substrate
The bond strength was significantly influenced by the concentration of green tea extract from the solution that was applied to the dentin (p = 0.012)
We sought to evaluate the effect of pretreatment on dentine affected by caries with a solution containing green tea extract, in different concentrations, since this polyphenol contains catechins, such as epigallocatechin gallate (EGCG), with proven inhibitory activity against MMPs22 and it is a crosslinking agent[16], which improve the mechanical properties of collagen
Summary
The longevity of adhesive restorations is directly related to the durability of the bond between adhesive systems and dental substrate. Exposure and degradation of collagen can occur over time, if hydrolytic degradation of the resinous components of the hybrid layer occurs, leaving the collagen exposed and unorganized[4] This situation is more aggravated in adhesive interfaces produced in caries affected dentine[5], a common and challenging dentin substrate that is available for adhesion in cavity preparations. Collagen eventually exposed can be degraded by enzymes with collagenolytic activity present in the dentin matrix, such as matrix metalloproteinases (MMPs)[6] and cysteine cathepsins (CTs)[7,8] Such degradation, along with the hydrolytic degradation of resin components, negatively affect the hybrid layer structure and lead to a loss of dentin bond strength over time[2], and this can directly affect the durability of adhesive restorations. In caries-affected dentin, there is an abundance of MMPs and CTs13, what highlights the importance of studying this type of dentin substrate in the context of strategies that can prevent bond strength decrease over time and increase the stability of adhesive interface
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
