This study is preliminary investigation attempting to establish a protocol for evaluating the possible effect of different root canal irrigants and self-etching adhesive agent on collagenolytic activity of Matrix Metalloproteinase enzyme. The purpose of the presented in-vitro study was to: 1.Evaluate and compare the effect of different irrigating solutions namely; 2% Chlorhexidine, MTAD, 17% EDTA and 5.25% NaOCl on the collagenolytic activity of matrix metalloproteinases in radicular dentin either with or without application of self-etch adhesive.2.Evaluate the effect of self-etch adhesive on the collagenolytic activity of matrix metalloproteinases.Seventy human permanent single-rooted recently extracted non-carious teeth with completed formed roots were collected, decoronated followed by cutting of 4mm. of the root apex. Cleaning and shaping of the root canal walls were performed using crown-down technique and sterile distilled water irrigation. Root dentin shavings were produced using Gates Glidden drills, collected in eppendorf tubes and rinsed with sodium azide to prevent bacterial growth.Results revealed that instrumented mineralized intraradicular dentin possessed low but detectable collagenolytic activity that was inhibited by 2% CHX, MTAD, 17% EDTA respectively with significant difference between the groups (p<0.001). On the other hand, both self-etch adhesive and 5.25% NaOCl activated latent MMPs and highly increased the collagenolytic activity in dentin with significant difference between the groups (p<0.001).