Mandibular lateral incisor-first premolar transposition in early mixed dentition: a rare case

Abstract

Dental transposition is an anomaly of eruption which is usually seen in the maxilla and rarely in the mandible. The mandibular lateral incisor's transposition with the permanent canine has a prevalence of less than 0.03%. The following case presents an even rarer situation, of a right lateral mandibular incisor that erupted in the place of the first premolar, in transposition with the temporary canine. In the first phase, a series of extractions have been performed, to ensure the necessary free space for moving the lateral incisor closer to its appropriate place, and after that a fixed orthodontic appliance was used. The biomechanics for intra-arch tooth movement was ingenious enough to ensure a perfect alignment of all permanent teeth and a functional Class I canine and molar final occlusion. Early intervention and successful move of the permanent canine in its correct position ensured the functionality of the mandibular movements and a good long-term prognosis.

Figure 1

Initial situation of (A) upper arch, (B) lower arch and occlusal relationships from (C) lateral right view, (D) lateral left view, (E) frontal view

Figure 2

Radiological examination: (A) Panoramic X-ray; (B) Lateral cephalometric X-ray.

Figure 3

Lateral incisor during treatment stages: (A) Position when bonding the lower fixed appliance; (B) Inclination correction by using open coilspring

Figure 4

Retroalveolar radiography showing the position of the permanent canine

Figure 5

Intraosseous position of the surgically-exposed left canine: (A) Its rapport to the lateral incisor; (B) The button bonded to direct its eruption

Figure 6

The left first premolar erupted too mesially

Figure 7

Repositioning of the canine: (A and B) Distal tractions to regain its space; (C) The right canine erupted in a good position

Figure 8

Final Class I functional and aesthetic occlusion