Besides the mid-palatal suture maturation stage, the morphology of the palate might also play a role in the effectiveness of miniscrew insertion planning or effectiveness of palatal expansion.

The aim was to assess the mid-palate length, height and surface area according to the mid-palatal suture maturation stage and its correlation to the maturity of the transverse palatine suture on cone-beam computed tomography (CBCT) maxillary images in a consequently selected group of subjects.

High-resolution CBCT images of 100 subjects (56 females, 44 males), aged 33.9±22.7 years, were selected. The images were clustered according to the mid-palatal suture maturation stage (stages B, C, D, and E) and 25 images per stage group were retrieved. The length, heights (at 2mm intervals) and surface area of the mid-palate were measured from the posterior border of the incisal foramen to the posterior nasal spine, and the maturity of the transverse palatine suture was recorded.

No between-stage-group differences were seen for mid-palate length, while heights and surface areas were significantly different between maturational stages. The mid-palate height was significantly smaller in maturational stages D and E groups (5.65±1.55mm and 5.77±1.70mm, respectively) than in groups B and C (6.97±1.82mm and 7.00±1.53mm, respectively). However, differences were significant only distally to the sixth mm measurement point. The surface area was significantly different among groups, denoting higher values for stage B and C (1.82±0.55cm² and 1.86±0.41cm², respectively), compared to stage D and E groups (1.53±0.38cm² and 1.57±0.54cm², respectively). A significant negative but poor correlation was seen between mid-palate total average height, surface area and mid-palatal suture stage (rho=–0.278, P=0.005 and rho=–0.222, P=0.027, respectively). Moreover, a very strong to moderate positive correlation (rho=0.847, P<0.001, rho=0.739, P<0.001) was seen between age and the maturational stage of the mid-palatal and transverse palatine sutures, respectively. Both the mid-palatal and transverse palatine sutures maturity stages were positively and very strongly correlated (rho=0.839, P<0.001).

The height and surface area of the mid-palate were significantly different among the maturational stage groups, while no differences were observed regarding the mid-palate length. Less mature sutures exhibit greater height and surface area values than more mature sutures. Although further research is needed in this regard, the mid-palatal suture maturational stage C showed greater distribution variability in terms of the transverse palatal maturation stages, which might be a discriminating factor between successful and unsuccessful skeletal palatal expansion, even with the use of skeletal anchorage devices.