Comparison of mandibular movements in TMD by means of a 3D ultrasonic system and digital caliper rule.

Objective: To compare the amplitude of mandibular movement measurements obtained by two different methods: the ultrasound JAM system and digital caliper rule in individuals with temporomandibular disorder (TMD) vs. controls. Method: Sixty individuals, without distinction between sex and age were evaluated: 30 with diagnosis of TMD (RDC/TMD) and 30 controls. Mandibular movements of opening, protrusion, and left and right laterality were measured by means of two Instruments: Digital caliper rule and 3D ultrasonic Jaw Motion Analyzer (JMA-Zebris Medizintechnik, Isny/Allgau, Germany). Data obtained were analyzed by descriptive analysis and compared by parametric statistics (Student's t-test), adopting a 5% level of significance. Results: When comparing the digital caliper rule with JMA, no significant differences were found for any of the movements evaluated (p > 0.05). In the comparison between groups, a difference was found in protrusion for both instruments used: JMA (p = 0.004) and digital caliper rule (p = 0.003), with the TMD group presenting reduced movement of protrusion when compared with the control group. Discussion: This study found no differences in obtaining the amplitude of mandibular movements when using the digital caliper rule or JMA system; both methods are effective. However, the ultrasonic system allows other types of analyses to be performed, such as the trajectory and speed of movement. Among the mandibular movements analyzed, protrusion was shown to be more compromised and limited in TMDs.