Prevalence, characteristic features, and complications associated with the occurrence of unerupted permanent incisors

This study examined the prevalence, characteristic features, and complications associated with the occurrence of unerupted permanent incisors among children and adolescents attending a university dental teaching hospital. A retrospective review was performed of the clinical records of children and adolescents who attended the Prince Philip Dental Hospital, Hong Kong between 2005 and 2014. All patients who had at least one unerupted permanent incisor tooth were included. A total of 266 subjects with 320 unerupted permanent incisors were identified. The prevalence of unerupted permanent incisors among children and adolescents was 2.0%. Permanent maxillary central incisors (70.6%) were the most commonly affected teeth. The most common cause for unerupted incisors were dilacerations (n = 83, 36.7%) for maxillary central incisors; developmental dental anomalies (n = 22; 30.6%) together with unfavorable root development (n = 22; 30.6%) for maxillary laterals incisors; and abnormal tooth/tissue ratio (n = 11, 50.0%) for mandibular incisors. A majority of unerupted incisors presented with complications the most common being ectopic/displacement/rotation of the unerupted incisors (46.6%), loss of space (36.9%) and midline shift (27.5%). In conclusion, the causes were distinct for different manifestations of unerupted permanent incisors. As the majority of unerupted incisors presented with complications, a systematic and organized method of history taking as well as clinical and radiographic examinations is mandatory in the diagnosis of unerupted permanent incisors.