THE EFFECT OF GREEN TEA EXTRACT AS A MATRIX METALLOPROTEINASE INHIBITOR ON THE BOND STRENGTH OF RESIN COMPOSITE

Objective: the aim of the study was to investigate the effect of epigallocatechin- 3-gallate (EGCG) from green tea extract as collagen cross linking agent on dentin bond durability at differ­ent aging times.
Materials and Methods: thirty sound premolars were used, they were divided into two groups (15 each) according to the pretreatment protocol. Mid-coronal flate dentine surface was obtained. Group A had no pretreatment done, where bonding agent was placed as the manufacturer instruc­tions. Group B had EGCG pre-adhesive conditioner rubbed before bonding procedures. Bond­ing procedure was followed by the application of nano-hybrid resin composite in tygon tubes for micro-shear bond strength measurement. Each group was further subdivided in to three subgroups according the aging protocol, where T1 specimens were stored for 24 hours, T2 they were stored for 6 months and T3 they were thermocycled.
Results: All data was statistically analyzed, where group B showed statistically significant higher mean bond strength values (19.5 MPa) than group A (12.1MPa) regardless of the aging pro­tocol. There was statistically significant change in micro-shear bond strength results due to aging regardless of the pretreatment. Where T1 revealed the highest mean values (17.1MPa) followed by T3 ( 15.5 MPa) and the lowest mean values were reported with group T2. There was a statistically significant decrease in mean micro-shear bond strength from T1 to T2 followed by non-statisti­cally significant change in micro-shear bond strength from T2 to T3. The mean micro-shear bond strength at T3 showed statistically significantly lower value compared to T1 value.
Conclusion: Green tea extracts (EGCG) is a powerful source of proanthocyanidin that has proved to be a good biological substitute as a cross-linker for preserving the integrity of dentin, enhancing the tooth resin composite inter-face when compared with universal adhesives present now a days in the market.
Recommendation: More long term clinical and laboratory studies are needed to assess the durability of adhesives