The Challenging Biomechanics in a Maxillary Lateral Incisor and Canine Transposition Malocclusion

Abstract

Dental transposition is an alteration that occurs in dental positioning, involving two adjacent teeth. Transpositions of canines are usually accompanied by other dental anomalies such as impaction of the incisors, missing lateral incisor, peg shaped laterals, rotations or dilacerations. Twenty percent of the transpositions involve the canine and upper lateral incisors. Dental transpositions are rare and may be complete or incomplete. The aetiology of transposition is still obscure. Several populations were studied to determine the prevalence of dental transpositions. Twenty percent of the transpositions involve the canine and upper lateral incisors. A clinical case is presented here, with canine and lateral incisor transposition and the biomechanics used in orthodontic treatment for the positioning of the canine in Class I and in the line of occlusion has been described. Correction of the transposition was performed with a fixed appliance for three-dimensional biomechanical control. The root of the left lateral incisor was moved to the palatal side to allow the movement, with the inclination movement of the crown, to distal the canine. The position of the miniimplant favoured distal movement without loss of anchorage of the teeth of this hemi-arch (left). With the canine positioned in place, third-order folds were inserted in the arch to move the lateral root to the buccal side. The canine was positioned in Class I relation in the line of occlusion with health, aesthetics, function and gingival and periodontal health remained stable after a year follow-up, demonstrating that the applied biomechanics were correct.

Keywords

• mini-implant
• orthodontics
• tooth migration
• tooth transposition