Table 3 The synthesis of results and conclusions of included systematic reviews

Kurt Popowich et al. (2002)

Canada

The MRI studies did not provide conclusive evidence of osseous remodeling or condyle position change. The tomography study demonstrated minor condyle position change. Methodological deficiencies prevented major conclusions regarding disc position

Laura Ivorra-Carbonell et al. (2016)

Spain

After treatment with functional appliances, the condyle was found to be in a more advanced position, with remodeling of the condyle and adaptation of the morphology of the glenoid fossa. No significant adverse effects on the TMJ were observed in healthy patients and the appliances could improve joints that initially presented forward dislocation of the disk

Lucas Garcia Santana et al. (2020)

Brazil

Low to very low certainty of evidence indicated that incremental mandibular advancement resulted in greater gains in mandibular length (MD = 0.89 [0.38, 1.34],p = 0.0005), anterior mandibular displacement (MD = 0.73 [0.40, 1.06], p < 0.001) and SNB angle (MD = 0.44 [0.02, 0.85],p < 0.04)

Karma Shiba Kyburz et al. (2019)

Switzerland

Currently existing evidence from controlled clinical studies on humans indicates that functional appliance treatment is associated with positional and skeletal alterations of the temporomandibular joint in the short term compared to untreated controls

Xinqi Huang et al. (2016)

China

The condylar position showed no changes after Herbst treatment. The condylar posterior space after Twin-block treatment averagely increased by 0.31 mm (P < 0.00001), whereas the condylar anterior space averagely reduced by 0.32 mm (P < 0.00001). Twin-block appliance enables forward movement of the condylar position