Comparative study using video analysis and an ultrasonic measurement system to quantify mandibular movement.

Objectives: This study provides a direct comparison between two registration systems used in quantifying mandibular opening movements: two-dimensional videography and electronic axiography, which is used as a reference.

Method: A total of 32 volunteers (age: 27.2 ± 6.8 - gender: 17 F - 15 M) participated in the study and repeated a characteristic movement, the frontal Posselt, used in the clinical evaluation of the temporomandibular joint.

Results: Frontal Posselt diagrams were reconstructed with the data gathered from both systems, which yielded acceptably similar data. Three commonly assessed parameters were obtained from each diagram and compared. These parameters were: maximum opening, right laterotrusion and left laterotrusion. Both descriptive statistics and the ANOVA test suggested that there was no significant difference between the estimated maximum opening parameter and the reference system (p = 0.217, 95% confidence). Laterotrusion values, on the other hand, appear to be overestimated by videography system and to show greater variability.

Discussion: Two-dimensional videography appears to be a suitable tool with resolution that is adequate for tracing mandibular movements - and opening values, in particular - for screening purposes, long-term observation, and as a quick check for dysfunction as far as frontal plane trajectories are concerned.

Conclusion: Reliability and acceptable quality of 2D videography data, acquired in this work, show that it has clear advantages for its wide application in the dental office due to simplicity and low cost for maximum opening measurement given the usefulness of this parameter in the detection of temporomandibular disorders.