This is the first study to evaluate the caries susceptibility of failed bonded interfaces.
The failed bonded samples showed an intermediate caries development between the non-bonded groups.
Lesion development was lowest for the non-bonded samples with bonding applied on the dentin and highest for the non-bonded samples with no bonding on dentin.
For the non-bonded groups, the self-etch adhesive showed deeper lesion and more mineral loss than the etch-and-rinse bonding material.
Mechanical loading aging resulted in deeper caries lesions than the water storage aging.