[Primary failure of eruption: diagnostics, treatment, casus and review of literature].

Primary failure of eruption is a rare eruption disorder of above all, the permanent second and sometimes the first molars. It is characterized by infra occlusion of the molars resulting in a severe lateral open bite. Primary failure of eruption is a disorders which affects all molars distal to the most mesial involved tooth. Diagnosis is possible both clinically and with radiographs. A panoramic radiograph combined with clinical findings of impaction or infra occlusion can confirm the suspicion of primary failure of eruption. Primary failure of eruption cannot be treated as other eruption disturbances are. The teeth do not respond to orthodontic force. Exposure of the molar and orthodontic traction of a molar affected by primary failure of eruption is discouraged. Observation and extraction, in case the primary failure of eruption poses a risk to the healthy dentition, are the only two treatment options for young patients. Additional treatment of this eruption disorder should be carried out at an adult age and consists of prosthetic closure of the open bite.