The objective of this study was to determine if the use of flat stabilization appliances would benefit patients with myogenous temporomandibular disorders. Methods. The studies chosen were randomized controlled trials which evaluated flat plane stabilization splints (SS) versus non-occluding palatal splints (NOS) for the treatment of myogenous temporomandibular disorders. The Cochrane Library, Medline through PubMed and Web of Science were searched for studies which met the criteria mentioned above. Results. Review authors assessed 544 unduplicated references which were reduced to eight randomized controlled clinical trials. Four were assessed at unclear risk of bias and four were at high risk. Patients wearing a flat plane stabilization splint only at night had a significantly better reduction in pain intensity (p=.015), and the subjects had a greater chance to have a 50% or more of reduction of pain intensity (p=.037) than patients wearing a non-occluding splint. However, there were no statistically significant differences between SS worn 24 hours a day and a non-occluding splint in reduction of pain intensity (p=.646) or number of responders to treatment (p=.323). There were no significant differences detected between SS (worn at night or 24 hours a day) and NOS in any of the other outcomes measured (tenderness of muscles of mastication at palpation, interincisal opening or clicking). Conclusions. There is low quality of evidence to support the use of flat stabilization splints worn only at night or 24 hours to provide a reduction of pain intensity in the treatment for myogenous temporomandibular disorders. Large RCTs with lower risk of bias and standardized methodology comparing stabilization splints to non-occluding splints are needed to confirm these results.