Palatal bone healing after removal of miniscrew-assisted rapid palatal expansion devices

Miniscrew-assisted rapid palatal expansion (MARPE) is an effective approach for correcting maxillary constriction in adults. This study aimed to evaluate palatal bone healing after miniscrew removal in MARPE-treated patients and to identify key factors influencing the healing process.

This retrospective study included 38 patients (18 men, 20 women; mean age at ≥6 months postremoval [T2], 24.7 ± 4.2 years) and analyzed 152 removal sites (76 anterior and 76 posterior). The average number of MARPE screw turns and expansion width were 29.5 ± 6.1 mm and 5.9 ± 1.2 mm, respectively. At the end of the consolidation phase (T1) and T2, miniscrew inclination, distance to the midpalatal suture, palatal bone thickness, and removal site dimensions (width, depth, volume, and total surface area) were measured. The average T1-T2 interval was 12.0 ± 3.7 months. Volume and total surface area healing ratios-representing percentage of bone recovery-were separately compared between anterior and posterior sites, and between monocortical and bicortical sites. Correlation analyses (point-biserial, Spearman, or Kendall's tau) assessed relationships between healing and patient-related and miniscrew-related factors.

All removal site dimensions decreased significantly at T2. Anterior and monocortical sites showed significantly greater healing. Posterior site healing ratios were significantly correlated with age at T2, healing duration, MARPE width, distance to midpalatal suture, palatal bone thickness, and anchorage type.

Substantial palatal bone healing occurred after miniscrew removal. Healing was greater at anterior and monocortical sites, whereas posterior site healing was influenced by patient/miniscrew-related factors. This study addresses concerns regarding healing at the miniscrew removal site after MARPE; however, long-term follow-up is recommended for comprehensive insights.