Crowding and rotation of tooth buds and maxillofacial or dentoalveolar trauma in childhood, ectopic eruption of an adjacent tooth, thickened overlying osseous or mucosal tissues, discrepancy in maxillofacial skeletal development or lack of correlation between maxillofacial skeletal development and tooth maturation, disturbances in eruption pattern, and consequences related to direct or indirect effects of cysts or neoplasm are the causes of tooth eruption failure