## 4 Results  
15 patients, 7 females and 8 males of average age 10.3 \(\pm\) 1.8, were treated with the F22(r) Young appliance by the same operator (F.C.r.) at the Postgraduate School of Orthodontics, University of Ferrara, for an average period of 10 months \(\pm\) 0.5 (maximum 11.5 months, minimum 10.5 months). According to [PERSON] et al. [8] CSV3 stage was valued in 10 patients (5 F, 5 M) and CS4 stage in 5 patients (2 F, 3 M). All measurements taken (18 in total) were repeated three times in order to calculate the intra-class correlation (ICC) index, and then estimate the average measurement error. As shown in Table 4, all outcomes had an ICC index \(>\) 0.94, indicative of excellent sample repeatability. Table 5 shows all the synthesized values, with the pre- and post-treatment averages found, along with the standard deviation and significant statistics according to the t-test \begin{table}
\begin{tabular}{c c} \hline
**Outcome** & **ICC Index** \\ \hline SNA & 0.969 \\ SNB & 0.975 \\ ANB & 0.952 \\ Wits & 0.974 \\ FMA & 0.986 \\ MP-SN & 0.984 \\ U1-Occl plane & 0.994 \\ U1-Palatal Plane & 0.947 \\ L1-Occl Plane & 0.941 \\ IMPA & 0.969 \\ SN-PP & 0.944 \\ PP-GoGn & 0.969 \\ Mand Base: Go-Pg & 0.974 \\ Mand Length: Co-Gn & 0.999 \\ OVJ & 0.987 \\ OVB & 0.961 \\ Right molar class & 0.998 \\ Left molar class & 0.998 \\ \hline \end{tabular}
\end{table} 
Table 4: Statistical repeatability analysis. ICC index report for each outcome. \begin{table}
\begin{tabular}{c c c c} \hline \multicolumn{4}{c}{**Linear Measurements on Digital Models (mm)**} \\ \hline Overjet & Overbite & Right molar class & Left molar class \\ \hline \end{tabular}
\end{table} 
Table 3: Linear values measured on digital models. applied. The statistical analysis was carried out and revealed significant differences between some pre- and post-treatment values but not for others. For each outcome, a bivariate graph was constructed according to the formula:  
\[ \begin{array}{c}\text{mean }\pm\text{ standard deviation}\\ \hline\text{time}\\ \end{array} \]  
The data showed that SNB angle increased statistically significantly from T0 to T1 (Figure 6), leading to a reduction in the ANB angle (Figure 7). Point B advanced significantly, resulting in a reduction in the sagittal skeletal discrepancy between the upper and lower jaws. The distance on the occlusal plane between points A and B also decreased significantly (Figure 8), and there was a weakly statistically significant increase in the MP-SN angle as a result of F22(r) Young treatment (Figure 9). The FMA angle, on the other hand, remained almost unchanged. As for the inclination of the incisors with respect to their skeletal base, there was a significant increase in the angle formed by the long axis through the lower incisor and the mandibular plane (IMPA) (Figure 10), but not of the angle formed by the upper incisor long axis and the bispinal plane, which was reduced by less than 1\({}^{\circ}\) as compared to the beginning of treatment (U1-PP). Finally, values for the mandible length, both total (Co-Gn) and at the base (Go-Pg), significantly increased as a result of treatment with the F22(r) Young appliance (Figures 11 and 12). With regard to the linear measurements obtained from analysis of the digital models, both the overjet and the overbite were significantly reduced, falling within normal ranges at T1. The molar class, measured as the distance between an axis passing through the vestibular groove on the lower first molar and the axis passing through the top of the mesiovestibular cusp on the upper first molar, also considerably decreased from T0 to T1, reaching values closer to 0 on both sides.