04 April 2021

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Detection of missing permanent incisors

Davide Elsido

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In the latest issue of European Journal of Orthodontics (February 2021) an article about the prevalence, distribution and age at clinical detection of missing permanent incisors was published, with consensus-based recommendations concerning diagnosis, risk factors, management.

Tooth agenesis represents one of the most frequent developmental anomalies in the human dentition. Prevalence differs depending on geographical location and sex. In Europe, tooth agenesis affects 4.6% of men and 6.3% of women. Excluding third molars, the most prevalent missing teeth are the mandibular second premolars, followed by the maxillary lateral incisors. Agenesis of the mandibular central or lateral incisors is much less common, and agenesis of the maxillary central incisors is extremely uncommon. The prevalence of maxillary lateral incisor agenesis varies significantly among different populations, with this prevalence ranging from 1 to 3%. Despite tooth agenesis being most frequently unilateral, maxillary lateral incisors agenesis seems to be most often bilateral.

Incisor agenesis is usually the earliest permanent tooth agenesis to be suspected clinically, as these teeth are expected to erupt early on following the sequence of tooth eruption. Agenesis in the anterior region may directly affect several aesthetic parameters including the smile, harmony of the dental arches, and midline symmetry. Studies show that in the face, the eyes, and teeth represent factors that most significantly determine aesthetic perception. Consequently, individual affected by agenesis of the incisors are confronted with problems which may impair self-confidence, especially during the sensitive adolescent period.

Upon diagnosing agenesis of one or more teeth in the anterior region, it becomes crucial to analyse various parameters such as the patient’s age, type of sagittal malocclusion, presence or absence of crowding, and profile type, before considering the treatment option. A question which remains open however is at what age is this agenesis initially clinically suspected. Following diagnosis, the optimal treatment in these cases remains subject to controversy, both in the literature and in clinical reality, where the decision of space opening followed by prosthetic replacement of the missing incisor, or space closure and tooth reshaping should ideally belong to a multidisciplinary team. This demonstrates the importance of multidisciplinary analysis of these patients with orthodontists collaborating with restorative dentists, implantologists, and prosthetic dentists.

The age at which incisor agenesis is initially clinically suspected is important, as this is when the dentist is likely to confirm this suspicion radiographically, or refer the patient to an orthodontist who will perform further investigations, potentially diagnose agenesis, and manage the case accordingly. The present study thus aims to determine the prevalence and distribution of clinically missing maxillary and mandibular permanent incisors, as well as the age at which they are detected, in a school-aged ethnically heterogeneous group of children.

A total of 2573 children (1415 boys and 1158 girls) between the ages of 4 and 13 underwent oral health screening on at least one occasion at the University clinics of dental medicine in Geneva, Switzerland, between 2001 and 2017. A total of 19 children, who had been seen for at least three consecutive years, presented with clinically suspected agenesis of at least one of their permanent incisors.

The age at detection ranged from 8.4 to 11.5 years.

The present study shows that, in the population studied, suspected maxillary permanent lateral incisor agenesis affects approximately 2% of children, and in roughly half of these cases this is bilateral. Suspicion of mandibular permanent incisor agenesis is less frequent, affecting approximately 0.5% of children. 

In cases of suspicion of permanent incisor agenesis, the latest age when this was detected clinically with a good degree of certainty in this study was by 11.5 years. Before this age, late eruption cannot be excluded in a definitive manner, despite clinical diagnosis or at least suspicion being made significantly earlier on some occasions, even before the age of nine as seen in the current study.In fact, the results of the present study show that in roughly a quarter of children where permanent incisor agenesis was suspected between the age of 9 and 10, this turned out to be a false positive finding, with late incisor eruption occurring. Radiographic confirmation at the age of 11.5 may therefore be justified and the need to confirm the clinical suspicion of agenesis may outweigh the potential risks of irradiation during childhood.

In conclusion the present study aimed to determine the prevalence, distribution and age at clinical detection of missing permanent incisors in children. Approximately 1 in 50 children presents with clinically missing maxillary lateral incisors and in half of these cases this is bilateral. Approximately 1 in 200 children shows one or more clinically missing mandibular incisors. The maximum age at detection of a clinically missing maxillary lateral incisor with a suspected agenesis is approximately 11.5 years, where agenesis can be assumed clinically with a good degree of certainty.