Teeth that are more often injured are the maxillary central incisors in both primary and permanent dentition [1]. The proximity between the root of the temporary tooth follicle and the permanent tooth easily explains why the permanent teeth are damaged. Injuries can cause different malformations located in the enamel or even in every permanent germ [2].

One of the consequences of trauma in primary teeth is the retention of his successor tooth [3]. A retained tooth is a tooth that remains retained wholly or partly beyond the normal time of eruption [4].

The retention of maxillary permanent incisor is often clinically and radiological diagnosed in early ages because the non-eruption of the anterior tooth causes concern to parents during early mixed dentition phase [5].

Figure 1. Clinical appearance left primary maxillary central incisor.

An 8-years-old girl reported to the Orthodontics Department at the University of Valencia (Spain) with the complaint of missing maxillary anterior tooth. As we can see in Figure 1, the upper left central incisor permanent has not erupted, persisting even primary incisor In her clinic history related a previous trauma 2 years ago in the primary upper left central incisor without producing symptoms during this time.

Figure 2. Pre-treatment panoramic radiographic.

Examination of oral cavity revealed that a mixed dentition with an alteration of the eruption in the permanent upper left central incisor.

In the occlusal analysis we observed a dental class I with a slight discrepancy index in the lower arch, with adequate overbite and overbite.

Figure 3. Radiographic appearance left primary and permanent maxillary central incisors.

Radiological examinations were performed to complete clinical evaluation.

Panoramic radiograph showed a mixed dentition in different stage of formation and the persistence of the primary upper left incisor (Figure 2 and 3).

After the initial diagnosis, it was decided to conduct a combined orthodontic and surgical treatment. In the panoramic, we could check that there was no obstacle that caused the retention of the permanent incisor (Figure 2 and 3), so it was decided to perform the extraction of the primary upper left central incisor to stimulate the eruption of its successor and to remove surgically part of the soft tissue ahead of the permanent incisor (Figure 4).

Figure 4. Occlusion frontal view with the extraction of the primary incisor.

Simultaneously, it was decided to place a McNamara-type expander in order to mobilize the incisor retained, not to expand the maxilla because there was no cross bite. After activating 21 days the expander, the permanent incisor began erupting (Figure 5).

The impacted maxillary right central incisor was successfully brought into proper position. The final appearance of the tooth was esthetically pleasing, with gingival margins at the same level with similar clinical crowns sizes. The tooth responded well to vitality and did not show abnormalities in crown shape. No pulp pathology or color change was found (Figure 6).

Figure 5. McNamara-type expander.

Retention of maxillary permanent incisors is a frequent case in dental practice, but its treatment is challenging because of the importance of these teeth in facial esthetics. Anterior primary maxillary impacted teeth are of concern to both the dentist and the parents because of the problems it poses for esthetics, speech, and mastication, and for its psychological effects.

The retained permanent teeth commonly results in migration of adjacent teeth leading to the space loss and hence insufficient space available for the movement of impacted tooth in the desired position [6]. In this case, the clinical as well as radiographic examinations clearly showed that there was enough space available for the eruption of the impacted maxillary left central incisor.

Figure 6. Post-treatment frontal view of the occlusion with the eruption of the permanent left central incisor.

Orthodontic and surgical intervention should not be delayed to avoid unnecessary difficulties in aligning the tooth in the arch [7]. In this case, the available space for tooth alignment was sufficient and tooth was brought into right anatomical position in the dental arch.

Impaction of maxillary incisor can be a challenging orthodontic problem. The treatment of an unerupted tooth will depend on its state, position, and presence of enough space in the dental arch to accommodate. If eruption is delayed, the permanent tooth should be exposed because it is important to allow the tooth to erupt into correct position as soon as possible.