Stability of early anterior open bite treatment: a 2-year follow-up randomized clinical trial

This 2-year-follow up study compared and evaluated the stability of early anterior open bite (AOB) treatment based on different appliances. Children from 7 to 10 years with Angle Class I, AOB larger than 1.0 mm and fully erupted maxillary and mandibular permanent central incisors were eligible. The initial sample was 99 patients distributed, by simple randomization, into four groups: BS (bonded spurs), CC (chincup), FPC (fixed palatal crib) and RPC (removable palatal crib). Cephalometric analysis was performed at baseline (T1), final (T2) and 2-year post-treatment (T3) by taking the overbite measurements as the main outcome. Blinding was possible to cephalometric analysis. At T3, with dropouts, there were 63 individuals, being BS (n=15; overbite 0.19 mm; 11.54 years; 10 female (F)/5 male (M)); CC (n=11; overbite -0.19 mm; 11.41 years; 8 F/3 M); FPC (n=21; overbite 1.23 mm; 11.44 years; 15 F/6 M) and; RPC (n=16; overbite 0.73 mm; 11.67 years; 6 F/10 M). Changes in dentoskeletal variables and breaking deleterious oral habits during the follow up were statically analyzed with p<.05. Mandibular skeletal linear measurements and vertical dental components have gradually increased with age, manly at pubertal growth spurt and at the establishment of permanent dentition after treatment. Incisor teeth extrusion had impact on AOB correction and stability in 4 groups, which recorded a 1.15 mm-improvement of overbite after treatment (T3-T2). The experimental appliances were effective with stable results, being FPC the device recorded the highest AOB correction and the lowest patient withdrawal rate.