## 3 Results  
The method error of cephalometric measurements ranged between 0.5 (molar relationship) and 1.1 (Wits appraisal) mm for linear measurements and between 0.5\({}^{\circ}\) (SNB) and 1.1\({}^{\circ}\) (CoGoMe) for angular measurements. Fifty-two patients treated consecutively with either RME/FM therapy (RME/FM group, 29 patients, 13 females and 16 males) or RMR therapy (RMR group, 23 patients,  
Figure 3: Removable Mandibular Retractor. Figure 2: Facemask (**A**) and bonded (**B**) and banded (**C**) Hyrax maxillary expansion appliances. 13 females and 10 males) at the Orthodontic Clinic of the Careggi University Hospital in Florence, Italy, were analyzed. Mean ages for the RME/FM group were 7.4 \(\pm\) 1.6 years at T1, 9.0 \(\pm\) 1.7 years at T2, and 15.1 \(\pm\) 1.4 years at T3. Mean ages for the RMR group were 7.7 \(\pm\) 2.5 years at T1, 9.4 \(\pm\) 2.3 years at T2, and 14.8 \(\pm\) 1.3 years at T3. No statistically significant differences between the two groups were found for any of the cephalometric variables at baseline (Table 1) with the exception of a significantly greater retrusion of the maxilla in the RME/FM group than the RMR group (SNA 78.2 and 80.4 degrees, respectively). As for the T1-T3 changes (Table 2), a significantly greater maxillary protraction (SNA +1.5 mm) was recorded in the RME/FM group with respect to the RMR group. The RME/FM group also showed significantly greater improvements in ANB and Wits appraisal (+1.9 degrees and +2.2 mm, respectively) with the RMR group presenting a slight worsening of these measurements (\(-\)0.9 degrees and \(-\)0.7 mm, respectively). No statistically significant changes could be found in vertical skeletal measurements. In the dentoalveolar region, the RME/FM group showed a significantly greater correction of the molar relationship (\(-\)1.5 mm) with the RMR group presenting a worsening of the Class III molar relationship (+1.2 mm). \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Variables**} & \multicolumn{2}{c}{**RME/FM**} & \multicolumn{2}{c}{**RMR**} & \multirow{2}{*}{**Diff.**} & \multirow{2}{*}{\(p\)} & \multicolumn{2}{c}{**95\% C.I.**} \\ \cline{2-2} \cline{6-8}  & **Mean** & **SD** & **Mean** & **SD** & & & **Lower** & **Upper** \\ \hline Age (years) & 7.6 & 2.3 & 7.1 & 2.8 & 0.5 & 0.473 & \(-\)0.9 & 1.9 \\ SNA (deg) & 1.9 & 2.0 & 0.4 & 2.5 & 1.5 & **0.031** & 0.1 & 2.7 \\ SNB (deg) & 1.0 & 2.6 & 1.3 & 1.8 & \(-\)0.3 & 0.597 & \(-\)1.6 & 0.9 \\ ANB (deg) & 1.0 & 2.0 & \(-\)0.9 & 2.0 & 1.9 & **0.002** & 0.8 & 3.0 \\ Wits (mm) & 1.5 & 3.0 & \(-\)0.7 & 3.1 & 2.2 & **0.012** & 0.5 & 3.9 \\ CoGn (mm) & 18.3 & 7.1 & 17.4 & 7.0 & 0.9 & 0.649 & \(-\)3.1 & 4.9 \\ SN-Pal. Pl. (deg) & 0.2 & 2.3 & 0.3 & 2.7 & \(-\)0.1 & 0.918 & \(-\)1.4 & 1.3 \\ SN-Mand. Pl. (deg) & \(-\)1.7 & 3.2 & \(-\)2.8 & 3.5 & 1.1 & 0.232 & \(-\)0.7 & 3.0 \\ Pal. Pl.–Mand. Pl. (deg) & \(-\)1.9 & 2.8 & \(-\)3.1 & 4.2 & 1.2 & 0.224 & \(-\)0.8 & 3.2 \\ CoCoMe (deg) & \(-\)3.2 & 3.2 & \(-\)3.6 & 4.6 & 0.4 & 0.978 & \(-\)0.2 \\ Mol. Rel. (mm) & \(-\)0.3 & 2.7 & 1.2 & 1.6 & \(-\)1.5 & **0.021** & \(-\)2.8 & \(-\)0.2 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Descriptive statistics and statistical comparisons (independent sample \(t\) test) for the starting forms (T1). \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Variables**} & \multicolumn{2}{c}{**RME/FM**} & \multicolumn{2}{c}{**RMR**} & \multirow{2}{*}{**\(p\)**} & \multicolumn{2}{c}{**95\% C.I. **}  
In the short-term (T1-T2, Table 3) the RME/FM group showed a significantly greater maxillary protraction (SNA +2.3 degrees), a significantly greater control in mandibular sagittal position (SNB \(-\)1.3 degrees), and significantly greater improvements in both ANB and Wits appraisal (+3.6 degrees and +2.6 mm, respectively) with respect to the RMR group.