International Journal of Advanced Engineering Research and Science (IJAERS) https://dx.doi.org/10.22161/ijaers.79.17
[Vol-7, Issue-9, Sep- 2020] ISSN: 2349-6495(P) | 2456-1908(O)
Qualitative and Quantitative Videofluoroscopic Analysis of Basic Temporomandibular Movements Ricardo De Bonis1, Sergio A. L. de Souza2, Hilton Koch3, Milton Costa4 1,2,3Department 4Biomedical
of Radiology, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil Sciences Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
Abstractâ&#x20AC;&#x201D; Background: The temporomandibular joint (TMJ) is a synovial condylar articulation with freedom of movement resulting from bilateral side morphological interrelations. Its basics movements to attend its main function are rotation and translation. Material and Methods: A videofluoroscopic study of the left posterior oblique incidence comprising 23 healthy volunteers of both sexes was conducted to qualify and quantify the displacement of the mandible over the temporal surface. This evaluation was performed without using any artificial contrast medium. Results: From maximum occlusion to maximum mouth opening, three spaces defined as LL1, LL2 and LL3 were established and used to qualify and quantify the limits of mouth opening. Seventeen volunteers could be classified as normal free (NF) and six as suspicious (S) based on this function. Conclusion: The NF and S groups statistically differed in their mouth opening capabilities (p < 0.0001). Measured values for LL3 greater than LL2 as well as positive values for L3-L2 can be considered NF and negative values for L3-L2 can be considered S with a significance of p < 0.0001. L2 was statistically confirmed as a good parameter for the distinction between normal and suspicious TMJ functioning. Keywordsâ&#x20AC;&#x201D; temperomandibular joint, pterygoid muscles, temporal bone.
I.
BACKGROUND
The temporomandibular joint (TMJ) is classified morphologically as a synovial condylar articulation, wherein one side interferes with the other, allowing interdependent articulation [1,2]. In theory, the condylar morphology and interdependence [3] may limit its movement pertaining to the opening and closing of the mouth. However, the dynamics of the TMJs allow freedom of movement beyond typical condylar movements. Beside the basic functions of rotation and translation, the jaw is also able to protrude, retract and move laterally both sides owing to spherical articulation to facilitate chewing [4,5,6]. The freedom of movement of TMJ results in bilateral morphological interrelation of the temporal articular surface (temporal fossa and tubercle) with the condyloid process of the jaw and fundamental articular disc interposition [7]. In
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the resting position, the free interocclusal space, a point at the centre of the condyloid process, is located near the middle projection of the temporal fossa [8], and during mouth opening, the condyloid process moves over the temporal tubercle until an unknown limit. In general, maximum mouth opening is evaluated by measuring the space between the superior and inferior tooth arcade with a ruler [9], a pachymeter [10], or the fingers [11] using the occlusal surface of the right superior and inferior incisors as a reference [10]. This inconsistent methodology suggests that the maximum normal mouth opening varies between 45 and that 60 mm in a normal adult and values <40 mm are indicative of pathology [12]. However, values between 40 and 45 mm, independent of sex, are considered the normal maximum limit of mouth opening [13]. The contract action of the chewing muscles, is the responsible for the displacement of the condyloid process in Page | 149