## 4 Discussion  
Treatment of orthodontic patients with TMD due to orthopaedic instability has always been challenging especially as one of the desired outcomes of the orthodontic therapy is the achievement of an orthopaedic stability with an ideal harmony between occlusal functions and TMJ [1]. Many case studies are available demonstrating TMD patients treated with stabilization splint and/or molar intrusion [5; 22; 23; 28; 29; 30]. But, so far a series of larger number of TMD orthodontic subjects, treated by stabilization splint followed by molar intrusion, with the main focus on TMJ health and CR-MI harmony have not been examined so extensively and studies have not been published yet. The aim of our study was to investigate and demonstrate that TMD patients with an orthopaedic instability can be effectively treated by the occlusal splint therapy followed by skeletally anchored molar intrusion. TMD is by far a complex disease and the nature of it is not completely understood [31; 32]. Most common signs and symptoms are masticatory muscle pain, TMJ sounds, limited movements (jaw opening capacity and deviations in mandibular movements), which tend to fluctuate with temporary remissions [33; 34]. It has been generally accepted that  
Figure 3: Representative superimpositions of presplit (T1) vs. postsplit (T2) (a) and postsplit (T2) vs. postintrusion (T3) (b) lateral cephalospor. Following splint wear (a), there was a significant increase in lower facial height and significant decrease in facial axis angle, which in turn increased ANB angle. After intrusion (b), mandible exhibited counterclockwise rotation, which was confirmed by decreased lower facial height, increased OB and facial axis angle and decreases in ANB. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Morphological Signs** & **Pretreatment Right** & **Posttreatment Right** & **_p_ Value** & **Pretreatment Left** & **Posttreatment Left** & **_p_ Value** \\ \hline Flattening & 61.11\% & 27.78\% & 0.0412 * & 72.22\% & 38.89\% & 0.0412 * \\ \hline Surface erosion, surface irregularities & 72.22\% & 22.22\% & 0.0077 * & 55.56\% & 22.22\% & 0.0412 * \\ \hline Irregular TMJ space & 66.67\% & 16.67\% & 0.0077 * & 61.11\% & 16.67\% & 0.0133 * \\ \hline Sclerosis & 22.22\% & 22.22\% & 1 & 11.11\% & 11.11\% & 1 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Frequency of osseous changes before and after therapy (* \(p\) < 0.05). TMD has a multifactorial origin [28]. There is still a debate, whether occlusion plays a role in the etiology of TMD, nevertheless, completely rejecting the role of it may be inappropriate [1,35]. It has been reported that TMD is closely associated with some type of malocclusions, such as open bite, deep bite and posterior cross bite [29]. Disharmony between CR-MI has been suggested to be a causative factor as well [2,5] and it has been showed that the degree of CR-MI discrepancy has a strong positive correlation with the severity of TMD signs and symptoms [3,5] and by achieving harmony between CR-MI during the orthodontic treatment decreases the risk of TMD. According to this, the mandible should seat ideally into MI during closure without condylar deflection from CR position caused by occlusal interferences [4,36,37]. Therefore, CR-MI harmony should be one of the major goals of the orthodontic treatment. In most of the published literature that have failed to prove an existing relationship between occlusion and TMD, several inadequacies are present; such as no instrumentation was used. Most of the studies used only questionnaires, clinical examinations and only dental cast [38,39]. In a review, [PERSON], [PERSON] and [PERSON] have also found relative low association between TMD and occlusal factors, although in the studies they reviewed, the occlusions were evaluated only intraorally and by using chin-point evaluation [40]. No attempt has been made to examine the condylar position and the possible effect on the stability of the TMJ by means of articulator models or precise determination of condyle with 3D imaging.