Under the name of pain we designate algies which cannot be attributed to a well defined syndrome or to a characterized disease. Sometimes it is possible, by the intermediary of clinical and radiological investigations, to uncover the causes of such pains, for example chronic pulpitis, denticles, impacted teeth, impacted root debris, cysts, enostoses, osteoid tumors, sequela of sinus surgery, etc. More rarely we can observe algies without anatomical substrate, located in the canine fossa and the zygomatic-alveolar crest. When looking for the causes of atypical pain, the participation of internal, neurological or psychogenous factors should not be forgotten.