IntroductionJunctional epidermolysis bullosa (JEB) is a rare genetic disease manifesting with skin and mucosal blistering. As part of the JEB, patients present with syndromic amelogenesis imperfecta (AI). Reports have described external crown resorption (ECR) in the teeth of patients with JEB, but its prevalence is unknown.ObjectiveTo determine the prevalence of ECR in patients with JEB.MethodsA longitudinal retrospective cohort study was performed at the Special Care Dentistry Clinic, University of Chile. Clinical records of patients with JEB between 2005 and 2024 were analysed. Prevalence of ECR per patient, per type of tooth and per tooth was calculated.ResultsOf the 20 patients examined, 90% presented ECR in at least one tooth, with an average of 4.8 primary and 6.8 permanent teeth affected. The most affected type of teeth were the incisors. 57.5% of primary incisors and 68% of permanent incisors had resorption. The most affected tooth was #82 in primary dentition (75%) and #32 in the permanent dentition (88.9%).ConclusionsThe prevalence of ECR in patients with AI due to JEB caused by variants in LAMB3 was 90%. Establishing clinical and radiographic dental protocols for the early detection of ECR is essential to prevent extensive tooth destruction.