## 4 Discussion  
This cross-sectional study was conducted to investigate the association between the severity of DD and the presence of GJH in pre-orthodontic growing patients evaluated with MRI, and to investigate the relationship between the stages of DD and age. MRI is an important tool for the imaging diagnosis of TMDs and has been considered the gold standard for the evaluation of the TMJ, because it provides detailed images of soft tissues and anatomical structures of the TMJ, especially of the articular disc and its position [33; 34; 35]. MRI can identify disc displacements in their early stages, enabling early and preventive treatment [33; 36]. In growing patients, it is crucial to detect issues in the TMJ as early as possible to address them effectively. Unlike other imaging techniques like computed tomography (CT), MRI does not use ionizing radiation, this makes it safe for use in young patients and avoids unnecessary radiation exposure [37; 38]. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Age Groups**} & \multicolumn{8}{c}{**DD Severity**} \\ \cline{2-10}  & \multicolumn{2}{c}{**Stage 0**} & \multicolumn{2}{c}{**Stage 1**} & \multicolumn{2}{c}{**Stage 2**} & \multicolumn{2}{c}{**Stage 3**} & \multicolumn{2}{c}{**Stage 4**} \\ \cline{2-10}  & **N** & \% & **N** & \% & **N** & \% & **N** & \% & **N** & **\%** \\ \hline GR-I & \multirow{2}{*}{7} & \multirow{2}{*}{17\%} & \multirow{2}{*}{7} & \multirow{2}{*}{28\%} & \multirow{2}{*}{0} & \multirow{2}{*}{0} & \multirow{2}{*}{0} &  
The DD is the most common TMJ internal damage condition. It was diagnosed in the general population and is also present in children and adolescents [7; 39; 40; 41; 42; 43]. In the present study, the most common DD was DDwR, a result that is in agreement with several authors. [PERSON] et al. [2], in their systematic review, reported a higher prevalence of DDwR than DDwoR in developmental individuals of the general population. While [PERSON] et al. [44] evaluated pre-orthodontic adolescents with a high prevalence of DDwR. Various hypotheses have been put forward to explain the etiopathogenesis of abnormal disc position, including ligamentous hypermobility [45]. The TMJ can be affected by GJH, receiving an overload, and, as a consequence, suffers degenerative changes which can produce internal derangements [46]. The articular disc is maintained in the normal position on the condyle thanks to the action of the collateral ligaments [3]. The higher prevalence in this study of DD in growing patients with GJH could suggest greater laxity of the ligaments that hold the disc in its normal anatomic relationship with the condyle, which over time could lead to continued damage to the ligaments. Some studies show that in the TMJ of GJH subjects there is an increased risk of articular disc displacement and a lower risk of reduced mouth opening capacity [47; 48]. These data agree with the results of this research; subjects with GJH, compared to the control group, have a higher percentage of DD, with a 4-fold increased risk of presenting DD for patients with GJH. Other authors suggest that there is no such correlation between GJH and DD; however, they did not study growing patients [46; 49]. DDwR was the most frequent DD in the whole sample, as reported also by other authors [7; 8; 9; 15]. However, in the age distribution, it is important to note that DDwR occurred only in age group III from 12 to 14 years. This result could be explained by the suggestion of some authors who propose that DDwR would be the first stage of disc displacement, which could evolve into DDwoR [11; 15; 40]. However, the literature is controversial on this aspect, as some authors report that this evolution is not evident. In the systematic review conducted by [PERSON] et al. [50], it emerges that DDwR is usually a stable, painless condition and accompanies the patient throughout life depending on the adaptive physiological processes that may occur.