To analyze the MRI features of temporomandibular disorders (TMD) patients and the value of MRI in evaluating the treatment effect of RW-splint.

Thirty-two patients diagnosed with TMD underwent MRI examination, and the MRI features of sixty-four sides of temporomandibular joint were analyzed retrospectively. Twenty-one patients received RW-splint treatment and underwent MRI examination after treatment, the change of angle of disc-condyle and disc length were analyzed after RW-splint treatment.

In sixty-four sides joints, forty-six discs were found morphogenetic changes, twenty-one joints showed anterior disk with reduction and twenty-five joints showed anterior disk without reduction. Forty-six mandibular condyles showed osteoproliferaion and cortical bone deficiency in varying degrees, thirteen mandibular condyles showed hyperkinesia and five mandibular condyles showed movement restriction. Ten sides showed arthoedema. After the treatment, the angle of disc-condyle in patients with reversible anterior disc displacement decreased from (25.7 ± 2.6) ° to (19.1 ± 1.6) °, the disc length decreased from (11.1 ± 1.3) mm to (9.1 ± 0.7) mm, the change of angle of disc-condyle and disc length were statistically significant (t_angle= 2.889, P_angle= 0.014; t_length= 2.354, P_length= 0.023) . After the treatment, the angle of disc-condyle in patients with irreversible anterior disc displacement changed from (26.4 ± 2.3) ° to (24.1 ± 2.1) °, the disc length decreased from (12.0 ± 1.3) mm to (11.9 ± 1.2) mm, and the change of angle of disc-condyle and disc length were not statistically significant (t_angle= 1.897, P_angle= 0.082; t_length= 1.076, P_length= 0.124) .

MRI can not only be used to diagnose TMD, but also can evaluate the treatment effect of RW-splint objectively.