Comparative evaluation of skeletal and dentoalveolar changes using two miniscrews versus four miniscrews assisted rapid palatal expansion in young adult patients with a transverse skeletal discrepancy: a cone-beam computed tomography study

Transverse maxillary deficiency is considered a common problem,  affecting 7.9% of adolescents and nearly 10% of adults. Rapid palatal expansion (RPE) has been widely used in the field of orthodontics since the mid-1960s for increasing the transverse dimensions of the maxilla in growing patients.Rapid palatal expansion enables the separation of the mid palatal suture, which is followed by skeletal orthopaedic expansion.Conventional tooth-anchored RME  could cause dentoalveolar tipping, less skeletal movement, and a lack of long-term stability. This tipping is usually accompanied by some extrusion.These dentoalveolar changes can contribute to vertical changes.

However, the fused, mature mid palatal suture and adjacent articulations limit the desired results for nongrowing patients using conventional RME.To reduce possible unwanted side effects and limitations of conventional RME, Mini-implant assisted rapid palatal expansion appliance (MARPE) was designed to increase the maxillary width in nongrowing patients using mini-implants placed in the cortical bone of the palate and nasal floor (NF).

MARPE could produce more favourable orthopaedic and less dentoalveolar side effects as compared with conventional tooth-borne RME.

There is scarcity of evidence in literature to compare two screws MARPE appliance and four screws MARPE appliance regarding skeletal and dentoalveolar effects.  Four mini screws have more skeletal anchorage than two mini screws mini-implants due to increased number of implants and increase in amount of surface area. This study is done to compare the differences in skeletal and dentoalveolar changes between two screws mini-implant and four screws mini-implant