Posteroanterior cephalometric changes in subjects with temporomandibular joint disorders
ABSTRACT Objectives The aim of the study was to establish the changes in posteroanterior cephalometric variables in subjects with temporomandibular joint disorders (TMDs). Methods Posteroanterior cephalograms of 61 subjects (age range 16-36.6 years, standard deviation 4.88 years) were used to determine cephalometric differences. Subjects were classified according to the Research Diagnostic Criteria for Temporomandibular Joint Disorders into three groups: unilateral TMD, bilateral TMD and no TMD. 14 linear and angular measurements were assessed on the posteroanterior cephalogram. For assessing facial asymmetry, the asymmetry index for bilateral measurements was calculated between the right and the left side. In cases with unilateral TMD, the asymmetry index was calculated using the difference between the unaffected and affected side. The differences among multiple groups were analysed using the one-way analysis of variance test and Scheffé post hoc test. Results 47 subjects were females (77%) and 14 were males (23%). 19 subjects had unilateral TMDs and 16 subjects had bilateral TMDs. The asymmetry index of the distance from the horizontal plane to the antegonion was higher in subjects with unilateral TMD than in patients with bilateral or no TMD (p < 0.05). Also, the asymmetry index of the distances from the vertical plane to the condyle (p = 0.05), gonion (Go) (p = 0.0004), antegonion (p = 0.002) and chin (Ch) (p = 0.02) was higher in subjects with unilateral TMDs. The asymmetry index of the O point-Go-Go' and O point-Ch-Ch' angles differed significantly in subjects with unilateral TMDs (p < 0.05). Conclusions Unilateral TMDs are associated with changes in posteroanterior cephalometric measurements. The assessment of posteroanterior cephalometric variables could be used as a key factor for evaluating the presence of TMDs.
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ABSTRACT: Internal derangement (ID) of the temporomandibular joint (TMJ) can cause facial asymmetry. The purposes of this study were to analyze the relationship between facial asymmetry and TMJ ID by using posteroanterior cephalometric variables, and to compare the findings with the results of magnetic resonance imaging (MRI). The sample consisted of women seeking orthodontic treatment at Seoul National University Dental Hospital who had routine posteroanterior cephalograms and bilateral MRIs of the TMJ. To eliminate the influence of condylar hyperplasia on facial asymmetry, only those with SNB angles less then 78 degrees were selected (n = 63). They were classified into 5 groups according to the results of the MRI: bilateral normal disk position, unilateral normal TMJ and contralateral disk displacement with reduction (DDR), bilateral DDR, unilateral DDR and contralateral disk displacement without reduction (DDNR), and bilateral DDNR. Fourteen variables from posteroanterior cephalograms were analyzed with 1-way ANOVA to evaluate differences among the 5 groups. Subjects with TMJ ID of greater severity on the unilateral side had shorter ramal height compared with those with bilateral normal or bilateral DDR or bilateral DDNR. In addition, the mandibular midpoint deviated toward the side where the TMJ ID was more advanced. Subjects with a more degenerated TMJ on the unilateral side might have facial asymmetry that does not come from condylar or hemi-mandibular hyperplasia.American Journal of Orthodontics and Dentofacial Orthopedics 12/2005; 128(5):583-91. DOI:10.1016/j.ajodo.2004.06.038 · 1.44 Impact Factor
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ABSTRACT: One hundred patients with recently acquired, externally visible mandibular deformity and no history of previous extraarticular mandible fracture were selected for retrospective analysis. All had been investigated clinically and with radiography, tomography, and high-field surface-coil MR imaging to determine the presence or absence and extent of temporomandibular joint degeneration. Temporomandibular joint degeneration was found in either one or both joints of each patient studied. Chin deviation was always toward the smaller mandibular condyle or more diseased joint, and many patients either complained of or exhibited malocclusion, often manifested by unstable or fluctuating occlusion disturbances. Three radiologically distinct forms of degenerative vs adaptive osteocartilaginous processes--(1) osteoarthritis, (2) avascular necrosis, and (3) regressive remodeling--involving the mandibular condyle and temporal bone were identified in joints most often exhibiting meniscus derangement. Osteoarthritis and avascular necrosis of the mandibular condyle and temporal bone were generally associated with pain, mechanical joint symptoms, and occlusion disturbances. Regressive remodeling was less frequently associated with occlusion disturbances, despite remodeling of the facial skeleton, and appears to result from regional osteoporosis. Forty patients (52 joints) underwent open arthroplasty procedures, including either meniscectomy or microsurgical meniscus repair, at which time major radiologic diagnoses were confirmed. Surgical and pathologic findings included meniscus displacement, disk degeneration, synovitis, joint effusion, articular cartilage erosion, cartilage healing/fibrosis, cartilage hypertrophy, osseous sclerosis, osteophyte formation, osteochondritis dissecans, localized or extensive avascular necrosis, and decreased mandibular condyle mass and vertical dimension. We conclude that temporomandibular joint degeneration is the principal cause of both acquired facial skeleton remodeling and unstable occlusion in patients with intact dentition and without previous mandible fracture.American Journal of Roentgenology 09/1990; 155(2):373-83. DOI:10.2214/ajr.155.2.2115271 · 2.74 Impact Factor
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ABSTRACT: Changes in the functional shift of the mandibular midline and the condyles were studied during treatment of unilateral posterior crossbite in six children, aged 7-11 years. An expansion plate with covered occlusal surfaces was used as a reflex-releasing stabilizing splint during an initial diagnostic phase (I) in order to determine the structural (i.e. non-guided) position of the mandible. The same plate was used for expansion and retention (phase II), followed by a post-retention phase (III) without the appliance. Before and after each phase, the functional shift was determined kinesiographically and on transcranial radiographs by concurrent recordings with and without the splint. Transverse mandibular position was also recorded on cephalometric radiographs. Prior to phase I, the mandibular midline deviated more than 2 mm and, in occlusion (ICP), the condyles showed normally centred positions in the sagittal plane. With the splint, the condyle on the crossbite side was displaced 2.4 mm (P < 0.05) forwards compared with the ICP, while the position of the condyle on the non-crossbite side was unaltered. After phase III, the deviation of the midline had been eliminated. Sagittal condylar positions in the ICP still did not deviate from the normal, and the splint position was now obtained by symmetrical forward movement of both condyles (1.3 and 1.4 mm). These findings suggest that the TMJs adapted to displacements of the mandible by condylar growth or surface modelling of the fossa. The rest position remained directly caudal to the ICP during treatment. Thus, the splint position, rather than the rest position should be used to determine the therapeutic position of the mandible.The European Journal of Orthodontics 05/1999; 21(2):155-66. DOI:10.1093/ejo/21.2.155 · 1.39 Impact Factor