There are a lot of dental emergency situation. Especially on disabled or pediatric patient with negative behavior, accidental aspiration or ingestionof foreign body (ex: dental instrument) is one of the common accidents in dental procedure. Dentists and dental hygienists must have knowledgeabout the precaution and be ready to deal with foreign body aspiration during dental treatment, especially on the disabled. This is a case of anaccident during the dental treatment of 14-year-old female patient with cerebral palsy. During scaling, prolonged retained primary tooth which hadresorbed roots was fell into left bronchi. So we tried to remove the crown by endotracheal approach. Most ingested foreign bodies pass throughthe gastrointestinal tract spontaneously, but some of them need endoscopic or surgical removal. Moreover aspiration into broncho-trachea canbe more serious events and must be treated as emergency situation.