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.

Aim:The aim of the present study was to investigate the association between unerupted permanent incisors and dental anomalies among children and adolescents. Methods:The clinical records of patients between January 2005 and December 2014 were retrieved to identify those with unerupted permanent incisors. A retrospective audit on the presence or absence of any dental anomalies was done from all available records of the included patients. Results:A total of 266 patients with 320 unerupted permanent incisors were identified from the 15 987 patients in the study. Among the unerupted permanent incisors, 222 (69.4%) were associated with dental anomalies, which was significantly higher than those showing an absence of dental anomalies (N = 98, 30.6%, P < 0.001). For the unerupted maxillary central incisors, a significantly higher proportion was associated with supernumerary teeth (P < 0.001). For the unerupted maxillary lateral incisors, a significantly higher proportion was associated with the ectopic eruption of permanent canines when compared with other dental anomalies (P < 0.001). The presence of the ectopic eruption of permanent canine, double teeth, and hyperdontia was significantly higher among male patients with unerupted permanent incisors. Conclusions:Unerupted permanent incisors were associated with supernumerary teeth and ectopic eruption of permanent canines. Specifically, a higher proportion of unerupted maxillary central incisors was associated with the presence of supernumerary teeth, whereas a higher percentage of unerupted maxillary lateral incisors was associated with the ectopic eruption of permanent canines. K E Y W O R D S dental anomalies, ectopic eruption, permanent canines, supernumerary teeth, unerupted permanent incisors 1 | INTRODUC TI ON According to the updated clinical guidelines of Royal College of Surgeons of England, an observation or intervention is needed for unerupted permanent maxillary central incisors when there is aberration from the standard sequence of eruption, or the contralateral teeth have erupted >6 months ahead of the unerupted incisors, or both central incisors remain unerupted and the lower incisors erupted >1 year prior. 1 The incidence of unerupted maxillary incisors in 5-12-year-old children has been reported to be 0.13%, 2 while the How to cite this article: Tan C, Ekambaram M, Lee GHM, Yiu CKY. Unerupted permanent incisors and associated dental anomalies. J Invest Clin Dent. 2019;10:e12395. https://doi.