Treatment of Class II Malocclusion by Corrective Osteotomy and Distraction Osteogenesis in a Foal

Class II dental malocclusion is one of the most common malocclusions in horses. Few reports investigating various types of fixation techniques following corrective osteotomy as treatments have been published. The objective of this case report was to describe the treatment of type II malocclusion and outcome using distraction osteogenesis following corrective osteotomy and external fixation in a 7-month-old Trakehner colt. Initial CT imaging revealed an overbite of 38.64 mm, overjet of 33.23 mm, and maxillary retroclination of 92.29 degrees. An external fixator was constructed using two units of two 220 mm internal diameter × 6.3 mm one-third ring arches. The ring arches were interconnected by four 6 mm connecting rods. IMEX linear motors were placed centrally. The mandible was 3D printed (ABS-M30i) and the surgery was rehearsed. Under general anaesthesia, a fabricated bite plate was applied using interdental wiring, dental putty and acrylic. Partial mandibular osteotomy was performed 1 cm rostral to 706 and 806. The external fixator was anchored to the mandible using 4 mm pins. The osteotomy was then completed. Osteodistraction was initiated the day following surgery at 0.5 mm and increased to 0.75 mm twice daily after 12 days. Repeat radiographs 26 days postoperative revealed appropriate alignment of the incisors and mandibular distraction was discontinued. Implant removal was staged. The bite plate was removed 74 days and the external fixator was removed 88 days postoperatively. No complications were noted throughout the postoperative period. Overall this minimally invasive approach for correction of type II malocclusion provided owner satisfaction and a good outcome. The IMEX motors provided an easy and precise method of osteodistraction.

Acknowledgment

None.

Publication History

Article published online:
15 July 2025