## 4 Discussion  
The systematic review and meta-analysis provided an assessment of the prevalence of temporomandibular disorders in children and adolescents, revealing that muscle pain was the most frequently observed TMD condition [17; 18; 27]. The most used tool to determine the diagnosis was DC/TMD Axis II [19; 28; 29]; its design facilitated the selection of studies providing adequate visualization [30; 31] and correct identification of symptoms, including mylagias in masticator muscles and masseaters, temporal, external and internal pterygoids, trapezius [32; 33] and scalene evaluated with the VAS pain scale and [PERSON]'s pain map, which helped with the clarity of the clinical diagnoses. The alterations in the condyle-disc complex were minimal, with inflammatory processes in the temporomandibular joint showing low and clinically insignificant prevalence. However, psychological factors were identified as relevant and warrant further investigation [34]. These factors, which are often overlooked in the early stages of the condition, must be considered, as they may contribute to the persistence and exacerbation of symptoms. [35] The RDC/TMD criteria were created in 1992 for research purposes, while the DC/TMD (2014) broadens the spectrum by including clinical observations; they are reliable and establish a valuable clinical standardization for the diagnosis of TMD [36] such as arthralgia, DDwR and DJD (osteoarthritis, osteoarthritis) [37]. The age of children and adolescents was variable in the results; however, 11.3% presented some symptom of TMD. When radiographic magnets were included to diagnose DD and DJD, the prevalence percentages of these pathologies were irrelevant [38; 39]. To determine and confirm diagnoses, the use of DC/TMD is recommended, as it considers joint sounds within short time frames (30 days) [40] and reports of crepitus as clinical signs that can better guide their differential diagnosis. It should be clarified that parafunctions in children between 3 and 8 years old are considered physiological, and they are even factors that stimulate facial growth. Outside this range, they become parafunctions, triggering joint pathologies if they are not diagnosed and treated. It should be noted that clinical examination protocols have little validity for diagnosing DDwoR compared to magnetic resonance imaging (MRI) [41] and the drawback found is that MRI is only used for cases with diagnostic difficulties. This leads to the idea that imaging may increase the prevalence rate in these cases by providing a more accurate form of verification. Unfortunately, there were few articles that used this diagnostic method [42]. The criteria for CD/TMD for children/adolescents found osteoarthritis and osteoarthritis in the categories \begin{table}
\begin{tabular}{l c c c c c c} \hline \hline
**Meta-Analysis** & **Prevalence (\%)** & **(95\% CI)** & **(I\({}^{2}\))** & **(t\({}^{2}\))** & **(p.i.)** & **(_n_)** \\ \hline Muscles pain & 15 & 9.6–19.4 & 99 & 2.3 & 1.8- 47.6 & 13 \\ \hline Overall any joint diagnosis & 11.3 & 7.6–16.4 & 96 & 0.4 & 2.3–40.4 & 11 \\ \hline Arthralgia & 1.9 & 0.9–3.9 & 69 & 0.3 & 0.1–26.7 & 4 \\ \hline Overall—disc displacements & 8.3 & 5.2–13.0 & 97 & 0.5 & 1.3–37.1 & 10 \\ \hline Disc displacement with reduction & 7.4 & 2.3 –21.2 & 98 & 1.8 & 0.0–90.5 & 5 \\ \hline Disc displacement without reduction & 0.2 & 0.0–0.6 & 0 & 0.2 & 0.0–5.1 & 4 \\ \hline Disc displacement without reduction & 0.0 & 0.0–0.3 & 0 & 0 & 0.0–1.9 & 4 \\ with limited opening & & & & & & \\ \hline Overall degenerative joint disease & 0.4 & 0.2–0.9 & 0 & 0 & 0.0–2.5 & 4 \\ \hline Osteoarthritis & 0.3 & 0.1–1.0 & 30 & 0.1 & 0.0–93.5 & 3 \\ \hline Osteoarthritis & 0.2 & 0.0–1.0 & 17 & 0.4 & 0.0–99.9 & 3 \\ \hline \hline \end{tabular}
\begin{tabular}{l c c c c c} \hline \hline  & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Summary of prevalence of temporomandibular joint disorders from meta-analysis. of low prevalence, indicating that they are less frequent disorders.