Orthodontic correction of overjet/overbite (‘parrot mouth’) in 73 foals (1999-2013).

The research conducted a retrospective study on the use of orthodontic tension bands and inclined plane biteplate for the correction of overjet or overbite in foals. The study analyzed the medical records of 73 foals that were treated at a single clinic by the same surgeon. It found that age and severity of malocclusion at the start of treatment significantly influenced the success rate and extent of correction.

Research Methodology

• The researchers employed a retrospective case series approach. Here, they looked into the past records of 73 foals treated for malocclusions at a single clinic, by the same surgeon.
• The foals were treated using orthodontic tension bands in combination with an inclined plane biteplate. An orthodontic tension band is a metal wire that exerts pressure to reposition teeth, and an inclined plane biteplate is a device that improves the contact between the upper and lower teeth.
• They calculated the overall change and change rates in overjet and overbite for each foal. Overjet is the extent of horizontal (anterior-posterior) overlap of the maxillary central incisors over the mandibular central incisors, and overbite is the vertical overlap of the maxillary central incisors over the mandibular incisors.
• They carried out a linear regression analysis to examine the association between potential explanatory variables like age, initial severity of malocclusion, and surgeon’s experience, and the outcomes.

Results

• The study reported improvements in overjet and overbite among 95% and 90% of the examined foals, respectively, with mean reduction rates of 9.9 and 8.4mm.
• Complete reduction of overjet was achieved in 25% of the cases, while functional correction of malocclusion was witnessed in 51% of the cases.
• It became evident through the analysis that the age of the foal at the start of treatment significantly affected the amount and rate of correction. Older animals exhibited decreased rates of overjet and overbite reduction.
• An increased severity of overbite at the start of treatment was found to be significantly associated with accelerated correction rates.
• Short-term complications noted included intraoperative hemorrhage, transient facial nerve neuropraxia and irritation to the mare’s udder by the brace. Long-term complications included the formation of gaps between cheek teeth (diastema) and discolouration and improper eruption of incisors.

Conclusion

• The research concluded that orthodontic tension bands combined with an inclined plane biteplate serve as an efficient method for correcting overjet and overbite in foals.
• The treatment worked quicker with lesser complications when initiated at an early age.
• Often, the application of more than one implant was needed for best results.