The use of maxillary expanders has the effect of distancing the maxillary bones at the level of the median palatal suture. During maxillary expansion, the main resistance forces occur at the zygomatico-maxillary sutures, and not in the median palatal suture, which is the basic principle on which this method is based. In this observational study, we evaluated possible complications at the skeletal and dentoalveolar level after palatal split using miniscrew-assisted rapid palatal expansion (MARPE) associated or not with corticopuncture (CP) therapy. The study included 27 patients with maxillary transverse deficiency and unilateral or bilateral cross-bite. Skeletal and dentoalveolar changes were evaluated using cone beam computed tomography (CBCT) images acquired before and after expansion. The mid-palatal suture was separated in 88.88% of cases, buccal bone height of the alveolar crest had decreased at first molar both at oral and palatal level by approximately 2.07 mm in 40.7% of cases whilst the remaining 59.3% showed insignificant bone loss, with canines exhibiting buccal tipping of 4.10° in 62.5% of cases. Changes of the occlusal planes were observed in 10 cases (37%). Maxillary canines tended to show symmetric buccal inclinations relative to the maxillary basal bone. Six patients; 22.22% showed hypertrophy/hyperplasia of the palatal mucosa associated with ulcerations, erythema, itching, and discomfort in the area. Swelling at the mid-palatal suture after split was observed in all cases and was caused by the resultant force. No cases of necrosis of the palatal mucosa were observed. Although occlusal modifications occur after palatal split, especially in unilateral cross-bite cases, these changes can be treated with the help of fixed orthodontic appliances.

Transverse maxillary deficiency currently affects 8–23% of adults. One of the most widely used orthodontic treatments today in patients with transverse maxillary defects is the maxillary skeletal expander (MSE). This was a retrospective observational imaging study regarding structural bone changes that may occur during healing after the placement of micro-implant assisted rapid palatal expanders (MARPE) in combination with cortico-puncture (CP) therapy. Regarding the magnitude of the mid-palatal suture opening, the mean split at the anterior nasal spine (ANS) and the posterior nasal spine (PNS) was 3.76 and 3.12 mm, respectively. The amount of split at the PNS was smaller than at the ANS, approximately 85% of the distance, showing that the opening of the midpalatal suture was almost parallel in the sagittal plane. On average, one-half of the anterior nasal spine (ANS) moved more than the contralateral by 0.89 mm. In the present study, we show that MARPE associated with CP therapy had a positive outcome on the midpalatal suture opening. This occurred in safe conditions, without post-surgery bleeding, and showing healing at the corticotomy level, with no signs of swelling or sepsis, which are side effects usually associated with more complex surgical treatments. Our results suggest that non-surgical palatal expansion, assisted by MARPE and CP, is achievable and predictable in young adults.