Maximizing Full Potential of the 3M™ MBT™ Versatile+ Appliance System in the Treatment of a Transposed Upper Canine

Any type of malocclusion with impacted teeth or ectopic eruption is considered a severe form of malocclusion, where an orthodontist would seek the help of a surgeon to either surgically remove the impacted teeth or to create an access for retrieval of the impacted teeth. There are times when teeth are erupted in a different location that will complicate the adjacent teeth during orthodontic tooth movement. Transposition of teeth usually can be seen between canine and premolars or canine and lateral incisor. The usual treatment is to do tooth substitution or to force the tooth to move to the correct position.

This is a case of a 14-year-old female patient presenting with skeletal class II malocclusion with normal overjet and overbite. Right molars are in Class II while left molars are in Class I occlusion. There was a presence of transposed upper right canine between the 1st and 2nd premolars. The upper right 1st premolar was rotated palatally (Fig. 1a-h).

Cephalometric analysis revealed a skeletal class II with ANB value of 4.5 degrees. Upper and lower dentitions were in normal position and angulation (Fig. 2a,b).

Panoramic radiograph showed the presence of all 3rd molars (Fig. 3).

Treatment Objectives

The patient was diagnosed to have a skeletal class II deepbite with transposed right canine with upper midline deviation to the right by 1mm. The objectives are as follows: 1. Position the upper right canine to the correct position 2. Shift upper midline to the left  3. Establish the occlusal support by achieving class I canine and molar relationship and 4. Correction of deepbite malocclusion.

Strap up of upper arch with 3M™ Clarity™ Advanced Ceramic Brackets 0.022 slot MBT prescription to level the upper arch and delay the placement of lower brackets due to the presence of deep bite. A bypass arch wire was used to protract the tranposed right canine (Fig. 4 a-c).

After 3 months, lower brackets were installed to align and level the arch (Fig. 5 a-c).

After 5th month, the canine was in the position mesial to the 1st premolar and NiTi open coil spring was used to further mesialize the canine. The 1st premolar was bonded with bracket and powerchain was used to rotate the tooth and position the tooth buccally (Fig. 6 a-d).

After 12 months, upper and lower 0.019 x 0.025 stainless steel arch wire with premolar and canine in proper position but right canine is still in class II relationship (Fig. 7 a-d). Patient was instructed to wear class II intermaxillary elastics to correct the class II canine and molar relationships.

The case was debonded after 1.5 years and upper and lower midline coincident with class I canine and molar relationship. The facial profile of the patient improved wherein the profile is straight and improvement of smile (Fig. 8 a-g).

The MBT System also provided a proper tip and torque particularly the anterior teeth and the posterior buccal overjet.

Cephalometric radiograph revealed a normal skeletal and dental inclination after orthodontic treatment and the panoramic radiograph showed normal bone level and absence of root resorption on the transposed teeth (Fig. 9 a-b, 10).

The transposed canine was successfully positioned in the right place without any damaged to the 1st premolar root and bone levels. Careful biomechanics in positioning the ectopic canine can be achieved with no resorption of the roots of the premolar and canine and gingival recession of the ectopic canine can also be prevented. The use of a couple mechanics together with a bypass arch wire will help reposition and rotate the transposed canine into the dental arch and the use of an optimal force can prevent the gingival recession of the tooth.

Different mechanotherapies are available including the use of mini screw implants to provide absolute anchorage while retrieving the impacted or ectopic tooth. The use of overlay archwire can also be helpful in positioning the ectopic tooth. However, appliance alone cannot achieve a good result unless proper biomechanics are used.