Effect of matrix metalloproteinase inhibitors on microtensile bond strength to dentin using self-etch adhesive - in vivo study

Objective: to investigate the effect of matrix metalloproteinase (MMPs) inhibitors in vivo on micro-tensile bond strength of resin composite to dentin using self-etch adhesive.Methods: Nine adult mongrel dogs were included in the study. A total of 90 standardized class I cavity were prepared in upper and lower (canine - first and second molar) in dog mouth. The teeth were divided into three main groups (n = 30) according to the type of MMP inhibitors were used: the control group (no MMPs inhibitors were applied), the CHX group (2% chlorhexidine digluconate, Kempetro, A.R.E), and the EDTA group (Ethylene diaminetetra acetic acid, META BIOMED, CO.LTD, KOREA). Each group were divided into two subgroups (n=15) according to the testing periods 6 months, and 12 months. At the end of each testing period, animals were sacrificed, then teeth were separated from the jaws. Each tooth was mounted on the cutting machine, and sectioned into a series of 1mm thick slabs under water cooling. Micro-tensile bond strength was measured for each sample by using universal testing machine. Data were tabulated and statistically analyzed.Results: Results of micro-tensile bond strength showed that after 6 months, CHX significantly revealed higher values than EDTA while after 12 months, CHX significantly revealed lower value than EDTA and control groups.Conclusion: The application of EDTA improve micro-tensile bond strength after 12 months of aging, while the bond strength decreased by aging for CHX and control groups.