## 4 Discussion
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline  & & \multicolumn{3}{c}{**OI-I**} & \multicolumn{3}{c}{**HSs**} \\  & & \multicolumn{3}{c}{**Mean \(\pm\) SD**} & \multicolumn{3}{c}{**Mean \(\pm\) SD**} & \\  & & \multicolumn{3}{c}{**(Minimum–Maximum)**} & \multicolumn{3}{c}{**(Minimum–Maximum)**} & \\ \hline  & N & **Pre** & **N** & **Post** & **N** & **Pre** & **N** & **Post** \\ \hline \multirow{2}{*}{**ROI-5**} & \multirow{2}{*}{-} & \multirow{2}{*}{NA} & \multirow{2}{*}{4} & 214.60 \(\pm\) 59.28 & \multirow{2}{*}{-} & \multirow{2}{*}{NA} & \multirow{2}{*}{4} & 209.99 \(\pm\) 36.88 \\  & & & & (165.73–289.16) & & & & (171.53–259.89) \\ \hline \multirow{2}{*}{**ROI-6**} & \multirow{2}{*}{-} & \multirow{2}{*}{NA} & \multirow{2}{*}{5} & 227.20 \(\pm\) 111.81 & \multirow{2}{*}{-} & \multirow{2}{*}{NA} & \multirow{2}{*}{4} & 262.74 \(\pm\) 105.87 \\  & & & & (116.41–367.03) & & & & (160.98–380.42) \\ \hline \multirow{2}{*}{**ROI-7**} & \multirow{2}{*}{4} & 1580.87 \(\pm\) 400.69 & \multirow{2}{*}{4} & 1672.69 \(\pm\) 197.85 & \multirow{2}{*}{4} & 1373.90 \(\pm\) 260.35 & \multirow{2}{*}{4} & 1360.09 \(\pm\) 164.62 \\  & & & & (1498.86–1852.58) & & & (990.65–1552.27) & & (1145.43–1512.30) \\ \hline \multirow{2}{*}{**ROI-8**} & \multirow{2}{*}{5} & 1659.02 \(\pm\) 523.16 & \multirow{2}{*}{5} & 1703.78 \(\pm\) 140.55 & \multirow{2}{*}{4} & 1336.22 \(\pm\) 88.68 & \multirow{2}{*}{4} & 1434.86 \(\pm\) 154.16 \\  & & & & (1458.11–1797.58) & & & (1267.89–1462.00) & & (1207.30–1549.45) \\ \hline \end{tabular}  
N: number of patients in which CBCT was performed. Data are expressed as HU. Pre: before third molar extraction; Post: after third molar extraction; NA: unavailable.  
\end{table} 
Table 2: _Cont._and, in this type of study, statistical tests yielding \(p\) values (or confidence intervals) are not needed and in most cases are also inappropriate as they typically do not include inferences or comparisons [34]. In addition, as a growing number of patients are particularly sensitive to ionizing radiation [48], CBCT in pediatric dentistry is controversial, and, consequently, it should be performed according to appropriate indications [26; 27; 28; 49; 29]. Thus, even though CBCT is a reliable tool that can be used for diagnosis, treatment planning and follow-up, unnecessary radiation exposure must be avoided. A further limitation of this study is the use of CBCT to assess BMD. Indeed, even though the gray values in the CBCT image are theoretically equivalent to the BMD, multiple factors including device/equipment (e.g., noise, scatter artifacts and beam hardening), software (e.g., reconstruction algorithm and FOV size) and patient (e.g., streak artefact) factors have to be considered to obtain reliable values [22; 23; 25]. As a consequence, CBCT does not appear a valid tool for the determination of BMD especially when values are used to compare different sites or for comparison with predetermined standard values [21; 25]. To overcome these limitations, deep-learning-based methodologies have been developed providing promising results [24]. In our study, CBCTs before and after third molar extraction in the OI-I patients and age-matched HSs were performed using the same equipment, ROIs and imaging conditions. In addition, the image resolution was improved by using a small FOV to increase the variability of gray values. Moreover, we did not make any comparison to predetermined standard values and evaluated symmetric sites in the right and left side of the mandible where the effects on the gray values are expected to be the same [25]. This approach made possible a comparative analysis of different ROIs between OI-I patients and age-matched HSs within the same group.