The incidence of centric slides in healthy individuals and TMD patients

Controversy exists as to whether centric slide is an etiological factor for temporomandibular disorders. In this cross-sectional study the magnitude of centric slides, obtained with 2 different articulations and one with a millimetre ruler was compared. The study enrolled a group of 27 healthy individuals and 83 TMD patients, the latter divided in 3 groups of 26, 28 and 29 subjects with the RDC/TMD diagnoses of myofascial pain, osteoarthritis and disc displacement without reduction, respectively. Measurement reliability of a chinpoint guided articulation was compared with a musculoskeletally stable articulation, obtained using a leaf gauge. Next, centric slide was measured, if any, intraorally with a millimetre ruler and in both articulations measuring the difference between centric relation and the maximal intercuspal position. A mandibular full-arch Tanner type stabilisation splint was fabricated for each of the TMD patients. After splint treatment, new casts were obtained and mounted using both methods to locate centric relation. The magnitude of centric slide intraorally and in both articulations was reassessed. For the analysis of the variables a mixed-model procedure was applied (alpha = 0.05). At baseline and upon conclusion of splint treatment all groups exhibited centric slides with large standard deviations (ranging from 1.03 +/- 0.83 to 1.97 +/- 1.3 millimetre). In the mixed-model procedure a significant difference in magnitude existed between the millimetre ruler and both the chinpoint guidance as well as the leaf gauge articulation (P < 0.001). No correlation between centric slide and TMD could be demonstrated.