This study evaluated the use of a fixed orthodontic appliance in treatment of temporomandibular disorder (TMD) compared to the use of an intra-oral splint. Fifty (50) adult patients, with confirmed anterior disk displacement with reduction in at least one temporomandibular joint (TMJ), were divided into three groups: 20 patients treated with AR splint (Group I); 20 patients treated with a fixed orthodontic appliance (Group II) and 10 patients who underwent no treatment (Control Group). Joint pain, joint noise, muscle pain, and subjective relief were evaluated monthly before the treatment began (T0) and for six months thereafter. Subjects in Group I and Group II displayed a significant decrease in joint pain (p < 0.01) from T2 and in muscle pain from T1 (p < 0.01) to T6. Subjects in Group I showed a higher decrease in the frequency of joint noise (p < 0.05) from T1 to T6, compared with Group II. At T2 and T3, the patients in Group II reported a significantly lower discomfort level associated with the devices than subjects treated with the AR splint (p < 0.05). However, at T5 and T6, this observation was inverted. The use of a fixed orthodontic appliance seems to be as efficacious as the use of an AR maxillary splint in the treatment of joint pain and muscle pain, but not in the treatment of joint noise. These results are valid, at least for the short-term clinical results (first six months of treatment). Clinical implications for long-term use are not clarified by these results.