## 3 Results
### Development of Symptoms of TMD  
None of the patients had clicking at T0, as this was one of the selection criteria. At T1, 27 patients (12%) developed clicking. However, one year after treatment as completed, only 10 patients (4.4%) continued to have clicking at T2 (Table 1). Prior to beginning orthodontic treatment, 115 patients (51.2%) had tenderness in their masticatory muscles, and 141 patients experienced tenderness in their cervical muscles (62.6%). This value actually increased during the course of treatment, and at T1, 145 patients had tenderness in their masticatory muscles (64.5%) and 155 had tenderness in their cervical muscles (69%). However, one year after completion of orthodontic treatment, the number of patients with masticatory muscle tenderness dropped to 101 (44.9%), while the number of patients with cervical muscle tenderness dropped to 127 (56.9%) at T2. Overall, the incidence of myofascal pain dropped from 56.9% before treatment to 52.9% after treatment (Table 1). The influence of multiple risk factors on the odds of developing TMD is highlighted in Table 1. It was clearly seen, even after ORs were adjusted for age, sex, and the presence of anxiety or mood disorders, that gender played a crucial role in the development of TMD. On average, women had 90% higher odds than men of developing TMD (Table 1, Figure 1). \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Sample \(n^{\circ}\) = 224** & \multicolumn{4}{c}{**Subjects**} \\ \hline  & **Males** & **Females** & **Total** & **\%** \\ \hline Gender & 105 & 119 & 224 & \\ Age at T0 (mean \(\pm\) SD in years) & \multicolumn{2}{c}{28 \(\pm\) 8.3} & & \\ Anxiety or depression at T0 & 18 & 39 & 57 & 25.4 \\ Somatic symptoms \(>\) 4 & 31 & 55 & 86 & 38.3 \\ Class I malocclusion at T0 & 55 & 61 & 116 & 51.9 \\ Class II malocclusion at T0 & 37 & 50 & 87 & 38.6 \\ Class III malocclusion at T0 & 14 & 7 & 21 & 9.5 \\ Extraction of premolars during treatment & 17 & 23 & 40 & 17.7 \\ Duration of orthodontic treatment (T1 \(-\) T0 in months) & \multicolumn{2}{c}{21 \(\pm\) 3.5} & & \\ Overjet (mm) at T0 & \multicolumn{2}{c}{5 \(\pm\) 4.1} & & \\ Overbite (mm) at T0 & \multicolumn{2}{c}{4 \(\pm\) 3.9} & & \\ \multicolumn{2}{c}{Tongue thrust at T0} & 49 & 45 & 94 & 42.1 \\ Oral hygiene status during treatment (plaque index & 64 & 54 & 118 & 52.5 \\ Silness/Loe \(>\) 2) [15] & \multicolumn{2}{c}{20} & 24 & 44 & \\ \multicolumn{2}{c}{TMD evaluation} & & & \\ \multicolumn{2}{c}{Males} & Females & Total & \% \\ Clicking of the TMJ at T0 & \multicolumn{2}{c}{Symptom free at T0 (selection criteria)} & \\ Clicking of the TMJ at T1 & 9 & 18 & 27 & 12.0 \\ Clicking of the TMJ at T2 & 3 & 7 & 10 & 4.4 \\ MTS score \(\geq\) 2 at T0 & 45 & 70 & 115 & 51.3 \\ MTS score \(\geq\) 2 at T1 & 55 & 89 & 145 & 64.6 \\ MTS score \(\geq\) 2 at T2 & 41 & 60 & 101 & 44.9 \\ CTS score \(\geq\) 2 at T0 & 62 & 78 & 141 & 62.7 \\ CTS score \(\geq\) 2 at T1 & 67 & 88 & 155 & 69.0 \\ CTS score \(\geq\) 2 at T2 & 55 & 72 & 127 & 56.9 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Characteristics of the sample. MTS = masticatory muscle tenderness score; CTS = cervical muscle tenderness score; T0 = before treatment; T1 = immediately after treatment; T2 = one year after treatment; SD = standard deviation. The presence of accompanying symptoms, both behavioral and somatic, prior to orthodontic treatment also influenced the development of TMD. In the study, 25.4% of patients reported symptoms of anxiety or depression prior to the beginning of orthodontic treatment. Moreover, at T0, 38.3% of the sample suffered from more than four somatic symptoms (occurring at least monthly), as was self-reported by the patients during the clinical interview. It was found that patients who reported these symptoms had 2.2 (anxiety or depression) and 3.6 (somatic symptoms) times greater odds of developing TMD. Other factors, including the type of malocclusion and the duration of orthodontic treatment, did not show any evidence of modulating the risk of developing TMD (Table 2, Figure 1).