Rapid palatal expansion in mixed dentition using a modified expander: a cephalometric investigation.

The aims of this investigation were to cephalometrically study the short-term skeletal and dental modifications induced by rapid palatal expansion in a sample of 20 patients (10 male, 10 female), aged 6-10 years (mean age 8 years) in mixed dentition with a uni- or bilateral posterior crossbite, a mild skeletal Class II malocclusion, and an increased vertical dimension (FMA, SN/\GoGn), and to compare them with an untreated matched control group of 20 subjects (10 male and 10 female), mean age 8 years. Cephalometric analysis showed that the maxilla displayed a tendency to rotate downwards and backward, resulting in a statistically significant increase of the SN/\PP angle (T0 = 9*95 degrees, T1 = 11*60 degrees, P < 0*01) and the SN-ANS linear value (T0 = 49*50 mm, T1 = 51*10 mm, P < 0*05). In addition, there was a statistically significant alteration of the anterior total facial height N-Me (T0 = 113*15mm, T1 = 114*15 mm, P < 0*05) and for the dental upper molar measurement U6-PP (T0 = 19*70 mm, T1 = 20*30 mm, P < 0*05). The small alterations found in the anterior total facial height and in the sagittal angles agree with previous studies, and suggest that RPE can be also used in subjects with a tendency to vertical growth and a skeletal Class II malocclusion.