## 4 Discussion  
The purpose of this study was to compare the use of two different palatal expander designs to evaluate the difference in skeletal and dental outcomes in pediatric patients. The devices traditionally used to treat crosshites--and also used in this study--are the rapid palatal expander with metallic bands bonded onto the first molars and the median screw (RME), and the palatal expander equipped with resin splints (SRPE) as an alternative to the metallic bands, usually referred to as a McNamara expander (2008; 2010). Even though current therapeutic approaches in orthodontics encourage the use of \"bone-borne\" techniques \begin{table}
\begin{tabular}{l c c c c c c} \hline \hline  & \multicolumn{3}{c}{**Group A (n = 38)**} & \multicolumn{3}{c}{**Group B (n = 36)**} \\ \hline
**Baseline Data** & **Mean** & **SD** & **Mean** & **SD** & **Difference** & \begin{tabular}{c} _p Value_ \\ _(t Test)_ \\ \end{tabular} \\ \hline Maxilla & & & & & & \\ \hline \begin{tabular}{l} Intermolar distance \\ (mesiobuccal cusp tips) \\ \end{tabular} & 7.3 & 3.4 & 7.6 & 5.1 & \(-\)0.3 & 0.54 \\ \hline \begin{tabular}{l} Intercanine distance \\ (mesiobuccal cusp tips) \\ \end{tabular} & 3.1 & 2.9 & 6 & 4.8 & \(-\)2.8 & 0.000 \({}^{*}\) \\ \hline Mandible & & & & & & \\ \hline \
\begin{tabular}{l} Intermolar distance \\ (mesiobuccal cusp tips) \\ \end{tabular} & 0.4 & 3 & 0.6 & 2.5 & \(-\)0.2 & 0.27 \\ \hline
\begin{tabular}{l} Intercanine distance \\ (mesiobuccal cusp tips) \\ \end{tabular} & 0 & 1.4 & 1.1 & 2.9 & \(-\)1.1 \({}^{*}\) & 0.1 \\ \hline Overjet & 0.6 & 1.4 & 0.2 & 1.7 & 0.4 & 0.76 \\ \hline Overbite & 0.5 & 1.5 & 0.6 & 1.4 & \(-\)0.1 & 0.35 \\ \hline \multicolumn{10}{l}{\({}^{*}\)_p_ < 0.01.} \\ \end{tabular}
\end{table} 
Table 6: Baseline measurements (mm) for comparison of T1–T0 changes. \begin{table}
\begin{tabular}{l c c c c c c} \hline \hline  & \multicolumn{3}{c}{**Group A (n = 38)**} & \multicolumn{3}{c}{**Group B (n = 36)**} \\ \hline
**Cephalometric Measurements** & **Mean** & **SD** & **Mean** & **SD** & **Difference** &
\begin{tabular}{c} _p Value_ \\ _(t Test)_ \\ \end{tabular} \\ \hline ANB (degrees) & \(-\)0.3 & 1.6 & \(-\)0.2 & 1.2 & \(-\)0.1 & 0.67 \\ \hline SNB (degrees) & \(-\)0.2 & 1.6 & \(-\)0.3 & 2 & 0.1 & 0.78 \\ \hline SNA (degrees) & \(-\)0.5 & 1.8 & \(-\)0.7 & 2.7 & 0.2 & 0.62 \\ \hline SN-GoGn (degrees) & 0.1 & 2.3 & 0.9 & 2 & \(-\)0.8 & 0.06 \\ \hline SN\_ANS\_PNS (degrees) & 0.1 & 2.6 & 0.7 & 2.3 & \(-\)0.5 & 0.56 \\ \hline ANS\_PNS\_GoGn (degrees) & \(-\)0.2 & 3.4 & 0.2 & 2.4 & \(-\)0.4 & 0.43 \\ \hline P-A face height (percentage) & \(-\)0.2 & 2.5 & 1.1 & 2.3 & \(-\)1.3 & 0.1 \\ \hline \end{tabular}
\end{table} 
Table 5: Cephalometric comparison of T1–T0 changes. to provide palatal vault expansion, especially in patients with increased maturation and interdigitation of the mid-palatal suture [13; 14; 15], the use of the abovementioned \"tooth-borne\" devices remains the primary therapeutic choice in growing patients affected by transverse deficiency [16; 17]. This is also because of the limited degree of acceptance of temporary anchorage devices among both patients and dentists [18; 19]. Dental side effects of traditional palatal expanders in the correction of posterior crossbite have been widely debated among experts. These relate mainly to the occurrence of buccal tipping of the upper molars, root resorption, and other side effects such as bone dehiscence and unstable results culminating in relapse [20]. This is of particular importance in all those cases with abnormal development of dentition, especially if misdiagnosis errors occur [21]. The findings of this study provide significant insights into the skeletal and dental effects of two different rapid maxillary expansion devices, the two-band expander (RME) and the splint resin palatal expander (SRPE), in children with maxillary contraction. Both devices effectively corrected posterior crossbite without inducing adverse vertical skeletal changes, making them suitable for use in hyperdivergent patients.