As the dental pulp is encased with a rigid, noncompliant shell, changes in pulpal blood flow or vascular tissue pressure can have serious implication for the health of pulp. Numerous studies have demonstrated that orthodontic force application may influence both blood flow and cellular metabolism, leading degenerative and/or inflammatory responses in the dental pulp. The aim of this case report is to present a case about tooth with chronic periapical abscess which showed normal vital responses. Excessive orthodontic force is thought to be the prime cause of partial pulp necrosis. Owing to remaining vital tissue, wrong dianosis can be made, and tooth falsely diagnosed as vital may be left untreated, causing the necrotic tissue to destroy the supporting tissuses. Clinician should be able to utilize various diagnostic tools for the precise diagnosis, and be aware of the endodontic-orthodontic inter-relationship.