Aim of study: This study was aimed to evaluate the effect of the application of a papain-based gel on the micro-tensile bond strength of different restorative material to carious dentin.Material and methods: Thirty two extracted human primary posterior teeth with moderate caries were assigned into two groups according to mechanism of caries removal, each containing sixteen (16) teeth [thirty two (32) halves].Group 1: Caries are mechanically removed with a round bur "control group " and restorative material was applied.Group 2: Caries are chemo-mechanically removed with a chemo –mechanical solvent (Papacarie) and restorative material was applied.Both groups were subdivided into two subgroups:Sub-group A: Glass iomomer restorationSub-group B: Light curing composite resin restoration.The samples were sectioned longitudinally to the long axis of the tooth to obtain sticks of standardized cross sectional area. These sticks were stressed to failure under tensile force in a universal testing machine.The micro-tensile bond strength for each specimen was calculated in megapascal (MPa).Results: Papacarie may decrease the bond strength of restorative materials regardless the type of adhesive filling.Conclusion: Papacarie may affect negatively the bond strength and consequently the durability of restorative materials.