Summary: Tooth ankylosis is a localized fusion of alveolar bone and cement of the tooth root. It occurs most frequently in temporary teeth, where it affected the mandibular molar teeth than the superior ones. Biological mechanisms and etiological factors participating in the origin have not been fully uncovered. The tooth ankylosis originates during or after eruption of teeth. It is considered as a progressive abnormality in teeth eruption, since other teeth are already in the state of continual eruption. The ankylosed tooth is firmly maintained in the bone and enters infraocclusion, which may unfavorably influence the neighboring teeth and the occlusion plane. These untoward complications are more apparent in earlier origin of ankylosis. Early diagnostics and therapy are therefore of importance. Individual diagnostic and therapeutic possibilities are discussed. The therapeutic decision making depends on the fact, whether the ankylosed tooth is deciduous or permanent, the time of ankylosis origin, the time factor of diagnosis establishment and the position of the affected tooth.

        Key words: tooth ankylosis – infraocclusion – tooth eruption abnormality