Matrix metallo proteinases are a group of calcium, zinc dependent host derived enzymes which are trapped within the mineralized dentin matrix during tooth development. These enzymes are thought to induce the degradation of bonding interphase in the composite restorations. A recent review suggested that various exogenous MMP inhibitors, can inhibit dentin MMPs, preserve the dentin hybrid layer, and stabilize the adhesive interface and increase bonding strength. However the synthetic inhibitors have the disadvantage of high cytotoxicity, mismatched mechanical properties, or unsatisfied long-term stability. Proanthocyanidins (PAs), as natural cross-linking agents, overcome some of these drawbacks and have been successfully used in the pretreatment of biological tissues to improve their mechanical properties. Recent studies have shown them to have the capability to control the MMPs activity. The objective of this study was to evaluate the effect of pretreatment with pomegranate peel extract on the shear bond strength of a two-step etch and rinse system. Study was carried out in two main groups of teeth samples (control and PPE treated). Half of of the samples in the both groups were subjected aging process. The shear bond strength was tested for all the samples. Results were compared with Immediate and aged samples. Even though mean shear bond strength was slightly higher for PPE treated 2^ndgroups, it showed that there was no statistically significant difference in bond strength for four groups

Keywords: Matrix metalloproteinase, Proanthocyanidin, Hybrid layer, Dentin biomodification.

1. Hashimoto, M., Ohno, H., Sano, H., Kaga, M. & Oguchi, H. In vitro degradation of resin-dentin bonds analyzed by microtensile bond test, scanning and transmission electron microscopy. Biomaterials. 24, 3795–3803 (2003).
2. Uno S, Finger WJ. Effect of mode of conditioning treatment on efficacy of dentin bonding. Oper Dent 1996;21:31–5.
3. Pashley DH, Tay FR, Breschi L, et al. State of the art etch-and-rinse adhesives. Dent Mater 2011;27:1–16.
4. Ding PG, Matzer AR, Wolff D, et al. Relationship between microtensile bond strength and submicron hiatus at the composite-dentin interface using CLSM visualization technique. Dent Mater 2010;26:257–63.
5. Ferreira, J. C., Pires, P. T., de Melo, P. R., & Silva, M. J. (2016). Etch-and-Rinse and Self-Etch Adhesives Behavior on Dentin. Adhesives: Applications and Properties, 1.
6. Suppa P, Breschi L, Ruggeri A, et al. Nanoleakage within the hybrid layer: a correlative FEISEM/TEM investigation. J Biomed Mater Res B ApplBiomater 2005;73:7–14.
7. Komori, P. C. et al. Effect of 2% chlorhexidinedigluconate on the bond strength to normal versus caries-affected dentin. Oper Dent. 34, 157–165 (2009).
8. Bedran-Russo AK, Pauli GF, Chen SN, et al. Dentin biomodification: strategies, renewable resources and clinical applications. Dent Mater. 2014;30(1):62-76.
9. Al-Rawahi, Amani& Edwards, Giles & Al-Sibani, Mohammed &AAl-Thani, Ghanim& Al-Harrasi, Ahmed &Rahman, Mohammad. (2014). Phenolic Constituents of Pomegranate Peels (Punicagranatum L.) Cultivated in Oman. European Journal of Medicinal Plants. 4. 10.9734/EJMP/2014/6417.
10. S Srinivasulu, S Vidhya, M Sujatha, S Mahalaxmi; Shear Bond Strength of Composite to Deep Dentin After Treatment With Two Different Collagen Cross-linking Agents at Varying Time Intervals. Oper Dent 1 September 2012; 37 (5): 485–491.
11. Epasinghe DJ, Burrow MF, Yiu CKY. Effect of proanthocyanidin on ultrastructure and mineralization of dentine collagen. Arch Oral Biol. 2017;84:29-36.
12. Balalaie, A., Rezvani, M. B., &MohammadiBasir, M. Dual function of proanthocyanidins as both MMP inhibitor and crosslinker in dentin biomodification: A literature review. Dental Materials Journal, March 2018 37(2), 173–182.
13. Bedran‐Russo, Ana Karina B., et al. "Application of crosslinkers to dentin collagen enhances the ultimate tensile strength." Journal of Biomedical Materials Research Part B: Applied Biomaterials: An Official Journal of The Society for Biomaterials, The Japanese Society for Biomaterials, and The Australian Society for Biomaterials and the Korean Society for Biomaterials 80.1 (2007): 268-272.
14. Han, Bo, et al. "Proanthocyanidin: a natural crosslinking reagent for stabilizing collagen matrices." Journal of Biomedical Materials Research Part A: An Official Journal of The Society for Biomaterials, The Japanese Society for Biomaterials, and The Australian Society for Biomaterials and the Korean Society for Biomaterials 65.1 (2003): 118-124.
15. Ayar, MuhammetKerim. "A review of ethanol wet-bonding: Principles and techniques." European journal of dentistry 10.1 (2016): 155.
16. Verma, Radhika, et al. "Long-term bonding effectiveness of simplified etch-and-rinse adhesives to dentin after different surface pre-treatments." Journal of conservative dentistry: JCD 16.4 (2013): 367.
17. Bedran-Russo, A. K. B., et al. "Mechanical properties of tannic-acid-treated dentin matrix." Journal of dental research 88.9 (2009): 807-811.

Dr Sajana.E.M

Postgraduate Student, Department of Conservative Dentistry and Endodontics, Sri Sankara Dental College, Varkala