Increase of condylar displacement between centric relation and maximal habitual intercuspation after occlusal splint therapy.

The present study assessed condylar displacement between initial maximal habitual intercuspation (MHI) and centric relation (CR), recorded after using a deprogramming occlusal splint for an average period of 7.8 +/- 2.1 months prior to any orthodontic treatment. The sample consisted of 22 subjects, 11 male and 11 female, with an average age of 14.2 +/- 1.4 years, with Class II malocclusion and with no apparent signs or symptoms of temporomandibular dysfunction (TMD). Condylar displacement was measured using a Panadent axis position indicator in decimal fractions of a millimeter. The original mean vertical displacements and the corresponding standard deviations were 4.24 +/- 2.53 mm and 3.86 +/- 2.72 mm, respectively, for the right and left sides. Because a significant negative correlation was observed between original condylar displacements and age factors, the displacement values were statistically adjusted to 2.74 +/- 2.00 mm and 2.44 +/- 1.93 mm. On the horizontal plane, the mean displacements measured were -0.72 +/- 1.53 mm on the right side and -0.51 +/- 1.98 mm on the left. The mean displacement on the transversal plane was 0.03 +/- 0.87 mm. A comparison between these values and those observed in non-deprogrammed groups, as well as those published in the related literature, indicates that use of occlusal splints results in greater mean condylar displacement values, especially vertically, between CR and MHI positions, which contributed to a more accurate orthodontic diagnosis.