Biomechanics of pivoting appliances

The effects of fulcrum-type splints on the temporomandibular joints are unclear. An analysis of bilateral temporomandibular joint linear tomograms of 20 volunteers was made. This study was carried out to evaluate and quantify the condylar distraction caused by the use of interocclusal splints with pivots located simultaneously on second molars. Statistical results showed an average condylar lowering of 1.3 mm in 87.5% of the subjects (P .05) while clenching with lips closed and wearing this splint. A real bilateral condylar distraction was shown in 30% of the subjects, 35% showed both condyles in a protruded position, and 35% of the subjects showed a combined situation.