Invasive cervical resorption (ICR) lesion is an aggressive form of tooth destruction that usually begins immediately below the epithelial attachment. It has been described as a purely inflammatory reaction that can be started by microorganism infection, or an aseptic resorptive process that can be secondarily infected. The potential etiologic and predisposing factors for ICR are orthodontic treatment, traumatic injuries, bleaching, periodontal therapy, and idiopathic factors. This case series with a 3-year follow-up shows that Class 2 ICR lesions have a good prognosis in 100% of cases. Class 3 ICR lesions should be considered at risk. However, in the authors' experience, the treatment of Class 3 ICR lesions is compatible with tooth maintenance.