Cieszyńrski was a Polish dentist who formulated the rules of isometry (Cieszyrński's isometry) in dental radiology, which enables precise dental X-ray pictures that show the true dimensions of teeth. Cieszyński also developed an extra-oral technique of anesthetizing the mandibular alveolar nerve, and a treatment for trigeminal neuralgia which involved injections of alcohol to the Gasser's ganglion. The clinical activity of Antoni Cieszyński included periodontal surgery (Cieszyński-Widmann-Neumann's operation) and surgery of abscesses and phlegmones of head and neck. He was also a member of numerous scientific societies (ADA, ASI, FDI) and a founder of the first Polish dental journal Polska Dentystyka (Polish Dentistry). On the 70th anniversary of Doctor Antoni Cieszyński's tragic death, the authors recall his outstanding and fruitful clinical career.