20-yr-old female presents to OMFS w/ CC of open bite in Jan 2013. Orthodontic tx + Orthognathic surgery was planned. Orthodontic tx initiated in Nov 2013. Wisdom teeth extracted in Jan 2016. Orthognathic surgery completed in Aug 2016. I saw the patient on Aug 2017 for assessment of discoloured teeth #1.3 and 2.1 that occurred following surgery. The patient was completely asymptomatic. Resorptive defects detected during radiographic examination. A full mouth survey was completed showing involvement of other teeth. All teeth except #1.3 and 2.1 (necrotic) responded to vitality testing. Patient only consented to CBCT of teeth #1.3 and 2.1 which were planned for NSRCT + internal bleaching. CBCT picked up teeth #1.2, 1.4, 1.5 and 2.2 with what appears to be external resorptive defects. NSRCT + internal bleaching completed in Nov. 2017. Patient’s history: Darier’s Disease, bilateral condylar resorption, no known allergy, denies previous trauma or surgery (other than orthodontic tx and Orthognathic surgery) and has never been in contact with a cat for any extended period of time. A blood test requisition was sent to investigate potential link with systemic markers including alkaline phosphatase, serum RANK/RANKL, OPG and estrogen levels… Unfortunately the patient did not go. To my knowledge, the patient is still asymptomatic. I am trying to get her in for follow-up. I prepared the patient that is recommended only if symptoms arise and that if these resorptions keep on progressing, extractions may be the only treatment.  Anyone ever seen something similar to this? Diagnosis? ECIR? Extracanal Invasive Resorption? Idiopathic? Potential Causes?