Evaluation of Mandibular Movement Functions Using Instrumental Ultrasound System

The article deals with routinely performed instrumental temporomandibular joint (TMJ) examinations and interpretation of findings obtained from the Arcus Digma ultrasound device in individuals with or without clinical symptoms of temporomandibular disorders (TMD). The aim of this study was to analyze mandibular movement functions and the relationship between incisors and condylar movement parameters during jaw opening, which may be helpful for clinical evaluation in these patients.

The study group consisted of 84 young students with no dental problems and other serious acute or chronic diseases in the medical history; the students were examined both clinically and with the Arcus Digma ultrasound device.

Helkimo Di = I was the most common score in 49 participants, and Helkimo Di = II in a significantly (p < 0.01, Di = I vs. Di = II) smaller number of participants. Medical history revealed symptoms of unilateral mastication in 15 participants and a statistically significant increased (p < 0.02, participants with symptoms of unilateral mastication vs. asymptomatic) condylar range of motion parameter during retrusion. Also a significant decrease (p < 0.03, participants with symptoms of unilateral mastication vs. asymptomatic) of the incisal and condylar ranges of motion during mouth opening was found. Limitation of mouth opening, defined as a decrease of inter-incisal distance, appeared in 19 participants (22.6%) and in 25 participants (29.8%) measured instrumentally with the Arcus Digma device. A comparison of instrumental result examinations of the right and left TMJs showed positive correlations of the range of mandible opening movement with the Posselt opening movement (r = 0.75) and opening/closing movements with the Posselt closing movements (r = 0.70). A correlation was demonstrated (r = 0.81) between the condylar range of motion studied on the left and on the right TMJ during mandible opening movement. Correlations were also found between opening-closing movements and the condylar range of motion of the left TMJ, and between the opening-closing movement and the condylar range of motion of the right TMJ during the opening movement.

According to the results of this study with instrumental Arcus Digma ultrasound device measurements of mandibular movements, data were provided on irregularities in TMJ function not detected in participants with or without clinical symptoms of TMD.