Case Report: A comparative evaluation of anterior open bite orthodontic treatment outcomes and stability of results in monozygotic twins.

Anterior open bite treatment represents an orthodontic challenge, mainly due to its' intricate etiology. This report presents the evolution of the orthopedic and orthodontic treatment of two female monozygotic twins, aged 10. Both twins presented dental and skeletal anterior open bite, tongue thrust, oral breathing, narrow maxilla with protrusion and fake spaces, dental and skeletal class 2, a hyperdivergent growth pattern and cervical vertebrae maturation stage 3. The therapeutic approach for both twins included an ENT examination, orthopedic treatment by means of High Pull Head Gear, trans palatal bar with an acrylic button at the level of the palatal loop, myofunctional exercises addressing the tongue thrust and the tonicity of the perioral muscles, a Roth 0.022 inch fixed preadjusted appliance and a tongue crib. Treatment results were different in the two patients, as for one of the twins tongue thrust was eliminated, enabling orthopedic and orthodontic correction of the open bite and presenting no signs of relapse at follow-up appointment, while for the other twin tongue thrust persisted, therefor the orthodontic correction of the open bite was only partial and presented with tendency toward relapse at follow-up appointment. Although the orthodontic diagnosis and therapeutic approaches were similar for both patients, the clinical outcomes were different mainly due to patients' compliance in the management of the tongue thrust and possibly, in the wearing protocol of the High Pull Head Gear.