Lateral cephalometric analysis of asymptomatic volunteers and symptomatic patients with and without bilateral temporomandibular joint disk displacement

Abstract

Few studies of dentofacial and orthodontic structural relationships relative to temporomandibular joint (TMJ) dysfunction have been reported. We undertook this investigation to determine any correlation of orthodontic and dentofacial characteristics with TMJ bilateral disc displacement. The population of patients was selected from a TMJ clinic where a control group of asymptomatic volunteers had been previously established and standardized. Differences in skeletal structural features were determined among three study groups: (1) asymptomatic volunteers with no TMJ disk displacement, (2) symptomatic patients with no TMJ disc displacement, and (3) symptomatic patients with bilateral TMJ disk displacement. Thirty-two asymptomatic volunteers without disk displacement (25 female, 7 male) were compared with the same number each of symptomatic patients without TMJ disk displacement and symptomatic patients with bilateral TMJ disk displacement. All subjects had undergone a standardized clinical examination, bilateral TMJ magnetic resonance imaging, and lateral cephalometric radiographic analysis. The groups were matched according to sex, TMJ status, age, and Angle classification of malocclusion. Seventeen lateral cephalometric radiographic cranial base, maxillomandibular, and vertical dimension variables were evaluated and compared among the study groups. The mean angle of SNB, or the intersection of the sella-nasion plane and the nasion-point B line (indicating mandibular retrognathism relative to cranial base), of the symptomatic patients-with-displacement group was significantly smaller than that in the asymptomatic volunteers and symptomatic patients without bilateral disk displacement (p < 0.05). Female subjects showed smaller linear measurements of mandibular length, lower facial height, and total anterior facial height than male subjects in all three groups (p < 0.05). The mean angle of ANB, or the intersection of the nasion-point A and nasion-point B planes (indicating retrognathism of mandible relative to maxilla), was significantly greater in female than in male subjects, in all groups (p < 0.05). Symptomatic patients with bilateral disk displacement had a retropositioned mandible, indicated by a smaller mean SNB angle compared with that in asymptomatic volunteers and symptomatic patients with no disk displacement on either side. Lateral cephalometric radiographic assessment may improve predictability of TMJ disk displacement in orthodontic patients but is not diagnostic; nor does the assessment explain any cause-and-effect relationship.

Dental occlusion and body posture: No detectable correlation

“…All the subjects had to comply with the following inclusion criteria: (i) good general health according to medical history and clinical judgment; (ii) negative history of vertigo through central nervous disease; (iii) negative for symptoms caused by any previous trauma or surgery; (iv) absence of any abnormalities after a neurological investigation, including assessment of vision and vestibular and lower leg sensory functions [9,10]; (v) absence of any particular episode of psychosocial and psychological stress profile in the last month; (vi) presence of a natural dentition and a bilateral molar support with a AE2 mm molar and canine Angle I relationship [11]; (vii) absence of any cross-, open-or depthbite; (viii) absence of cast restorations and extensive occlusal restoration; (ix) absence of any temporo-mandibular diseases diagnosed as previously described [12]. Posturography recordings were performed by using a 10-Hz sampling frequency vertical force platform (Lizard, Como, Italy) with subjects placed in a quiet stance.…”

Imaging diagnosis of the temporomandibular joint: critical review of indications and new perspectives

“…Does not substitute for other diagnostic imaging of the TMJ Bósio et al [34] Conventional tomography b Assessment of the bony components of the TMJ, at any depth, in full mediolateral thickness, generally taken in lateral views. May also be combined with frontal views.…”

“…Lateral cephalometric radiography provides little information about the TMJ [34], although it may be used to analyze structural variations, facial patterns, and their possible implications as predisposing and/or associated factors [35]. In a study of the correlation between orthodontic and dentofacial characteristics, symptomatic patients with bilateral displacement of the TMJ disk presented a retropositioned mandible, whereas asymptomatic volunteers and symptomatic patients without bilateral displacement of the disk did not.…”

“…In a study of the correlation between orthodontic and dentofacial characteristics, symptomatic patients with bilateral displacement of the TMJ disk presented a retropositioned mandible, whereas asymptomatic volunteers and symptomatic patients without bilateral displacement of the disk did not. This suggests that lateral cephalometric radiography could help in diagnosing disk displacement in orthodontic patients; however, this technique alone cannot be used for diagnosis, nor does its Thus, cephalometric evaluations must not substitute for other TMJ diagnostic imaging techniques [34] (Table 1).…”

The relationship between temporomandibular joint disk displacement and mandibular asymmetry in skeletal Class III patients

“…Facial symmetry is known to be an important characteristic in the etiology of TMJ ID. 12 It has also been suggested [13][14][15][16][17][18][19] that TMJ ID might be associated with skeletal changes. In addition, there exists a relationship between the type of malocclusion and the prevalence of asymmetry.…”