Stability, tipping and relapse of bone-borne versus tooth-borne surgically assisted rapid maxillary expansion; a prospective randomized patient trial

This study evaluated stability, tipping and relapse after surgically assisted rapid maxillary expansion (SARME), comparing bone-borne and tooth-borne devices, in skeletally matured non-syndromal patients with transverse maxillary hypoplasia. The study is a randomized, open-label, clinical trial. Patients were randomized to bone-borne (n = 25) and tooth-borne (n = 21) groups. The surgical technique for corticotomy was the same in both groups. Expansion was performed using a bone-borne or tooth-borne device. Dental study casts, lateral and postero-anterior cephalograms were taken before treatment, after the distraction phase and at 12-month follow up. Stability, segmental maxillary tipping and relapse were studied. 23 bone-borne and 19 tooth-borne patients were analyzed. There were no significant differences between the two groups. Widening was comparable at canine, premolar and molar level. Relapse was not significant and at follow up the significant increase in distance was sustained. A significant increase in palatal width, at premolar and molar level, occurred in both groups. The maxilla moves slightly downward in SARME. Segmental maxillary tipping occurred in both groups and did not affect relapse. There is no significant difference between the two groups. In SARME, the widening achieved at dental level is stable after 12 months. Over-correction is not necessary. Tipping of the maxillary segments and increases in the retention period are equal in both groups.