Determination the Condyle Position and Measurement of Joint Space by CBCT in Patients with Disk Displacement Compared with Healthy Control Group

Introduction: Disc displacement is characterized by a change in the articular disc position (abnormal position) which is located between the mandibular fossa and the head of the condyle. Disc displacement can be classified as 8 positions (abnormal disc position); however, the most common types are anterior and anterolateral displacements. When the displacement of the disc occurs, the bilaminar zone is moved against the articular surfaces, gradually replacing the function of the disc itself. It has mechanical properties modifications in vascular diminishment and nerve supply which induces the condition. Aim of the Study: To study the radiographical assessment of temporomandibular joint in patients with disk displacement by using cone beam computed tomography and determination of condyle position anterior, centric or posterior depending on the joint space measurements (anterior, superior and posterior joint space). Materials and methods: The study sample consisted of 78 patients with disk displacement and 31 as control subjects. Patients with intra articular joint disorders were divided into 4 groups according to the diagnostic criteria for temporomandibular disorders (Group 1-disk displacement with reduction, Group 2-disk displacement with reduction with intermittent locking, Group 3-disk displacement without reduction with a limited opening, Group 4-disk displacement without reduction without limited opening). Results: The results show the position of the condyle in right and left side more anteriorly in control than in patients with disc displacement, while the position of the condyle in patients was more posterior and superior. There was a highly significant difference in condyle position between the control group and Group 2, Group 3 and Group 4. Conclusions: Disc displacement is one of the causes that change the condyle position in the glenoid fossa.

Positional change in mandibular condyle in facial asymmetric patients after orthognathic surgery: cone-beam computed tomography study / 대한악안면성형재건외과학회지

BACKGROUND: We evaluated change in the mandibular condyle after orthognathic surgery using cone-beam computed tomography (CBCT) in patients with facial asymmetry. METHODS: Thirty patients with skeletal class III malocclusion and mandibular prognathism or facial asymmetry were classified into two groups according to the amount of menton deviation (MD) from the facial midline on anteroposterior (AP) cephalogram: group A (asymmetry, MD ≥ 4 mm; n = 15) and group B (symmetry, MD < 4 mm; n = 15). Position and angle of condylar heads on the axial, sagittal, and coronal views were measured within 1 month preoperatively (T0) and postoperatively (T1) and 6 months (T2) postoperatively. RESULTS: On axial view, both groups showed inward rotation of condylar heads at T1, but at T2, the change was gradually removed and the condylar head returned to its original position. At T1, both groups showed no AP condylar head changes on sagittal view, although downward movement of the condylar heads occurred. Then, at T2, the condylar heads tended to return to their original position. The change in distance between the two condylar heads showed that they had moved outward in both groups, causing an increase in the width between the two heads postoperatively. Analysis of all three-dimensional changes of the condylar head positions demonstrated statistically significant changes in the three different CBCT views in group B and no statistically significant changes in group A. CONCLUSIONS: There was no significant difference between the two groups in condylar head position. Because sagittal split ramus osteotomy can be performed without significant change in symmetrical and asymmetrical cases, it can be regarded as an effective method to stabilize the condylar head position in patients with skeletal class III malocclusion and mandibular prognathism or facial asymmetry.

Orthognathic surgery on Skeletal Class III patiens with collapsed vertical dimension: case report

Patients who lost posterior teeth due to periodontitis or dental caries have collapsed vertical dimension, unstable occlusion and change of the mandibular position. In particular, patients in orthognathic surgery, clinician should re-establish the pre-operative stable position of mandibular condyle in articular fossa and favorable vertical dimension for high post-operative stability of mandible. Therefore, interdisciplinary approach and co-operation, including prosthetics, orthodontics, oral and maxillofacial surgeon, from diagnosis and treatment plan is important to get a good outcome. This case report was patients who had collapsed occlusal plane due to severe dental caries on maxillary molars with skeletal Class III malocclusion. Before orthognathic surgery, resetting of maxillary occlusal plane with temporary removable denture was performed. Then successful multidisciplinary approach was done and lead to acceptable clinical outcome.

Avaliação da posição condilar e disfunção temporomandibular em pacientes com má oclusão de Classe II submetidos à protrusão mandibular ortopédica / Evaluation of condylar position and temporomandibular dysfunction in Class II patients treated with mandibular orthopedic advancement

OBJETIVO: avaliar a participação da protrusão mandibular ortopédica e da posição condilar na prevalência de sinais e sintomas de disfunção temporomandibular (DTM). METODOLOGIA: a amostra foi composta por 60 indivíduos divididos em 3 grupos, sendo o grupo I correspondente a indivíduos não tratados; o grupo II composto por jovens em tratamento com o Bionator; e o grupo III por jovens já tratados com este aparelho. Os indivíduos da amostra responderam a um questionário relativo aos principais sintomas de DTM, permitindo a classificação dos mesmos de acordo com a presença e severidade dessas disfunções. Esses jovens também se submeteram à avaliação da movimentação mandibular, palpação dos músculos mastigatórios e inspeção de ruídos articulares. Radiografias transcranianas padronizadas das ATMs direita e esquerda foram realizadas, para obtenção do grau de concentricidade condilar. RESULTADOS: os testes ANOVA, Kruskal-Wallis e qui-quadrado foram utilizados para análise dos dados. De acordo com os resultados do questionário anamnésico, 66,67 por cento da amostra foram classificados com ausência de DTM; 30 por cento com DTM leve e apenas 3,33 por cento com DTM moderada, sem diferença entre os grupos estudados (p > 0,05). Quanto à concentricidade condilar, o grupo II apresentou os valores de menor concentricidade (côndilos mais anteriorizados), com diferença estatisticamente significante em relação ao grupo I (p < 0,05). Uma associação entre a concentricidade condilar e a prevalência de DTM, no entanto, não foi encontrada. CONCLUSÃO: a protrusão ortopédica, apesar de alterar a posição dos côndilos, não aumentou a prevalência de DTM na população estudada.

OBJECTIVE: to evaluate the possible effects of orthopedic mandibular protrusion and condyle position in the prevalence and severity of Temporomandibular Disorders (TMD). METHODOLOGY: the sample was composed of 60 individuals with Angle Class II malocclusion divided into three groups depending upon the accomplishment of functional orthopedic treatment (prior, during and after therapy with the Bionator appliance). An anamnestic questionnaire, composed of questions regarding most frequent symptoms was used to classify the sample according to the TMD presence and severity. A clinical examination, including temporomandibular joint (TMJ) and muscle palpation, mandibular range of motion and joint noises analysis was also performed. Serial standard right and left TMJ transcranial images were taken with the teeth in intercuspal position, digitalized and condyle concentricity was determined. RESULTS: one-way ANOVA, Kruskal-Wallis and Chi- square accounted for data analysis. Based on the anamnestic questionnaire, 30 percent was considered as having mild TMD, while 3.33 percent had moderate TMD, with no difference between groups (p > 0.05). Group II (during therapy) has shown significant anterior condyle positioning (p < 0.05) when compared to group I, although no association was found between this variable and TMD presence or severity (p > 0.05). CONCLUSION: mandibular orthopedic protrusion was not a risk factor for TMD in the sample studied.

A cephalometric and panoramic analysis of the changes of the condylar position after orthognathic surgery

A comparative study on the standard and individually corrected radiographs in TMJ transcranial radiography / 대한치과교정학회지

Among the radiographs for temporomandibular joint, transcranial radiograph is widely used for screening and diagnosing temporomandibular disorder because it has sharp image and it is easy to take. This study was performed to compare condylar position and image sharpness in standard and individually corrected transcranial radiographs using Accurad-200 headholder. Submentovertex view, Reverse-Towne view, Standard and individually corrected transcranial radiographs of 45 university students who were randomly selected were traced, measured and analyzed. The results were as follows: 1. The means of condylar axes and lateral slopes were 16.8degrees and 22.5degrees respectively. There were no differences between male and female or right and left side. 2. Individually corrected radiographs showed smaller posterior joint space and larger anterior joint space than standard radiographs, but superior joint space did not show a statistical difference between standard and individually corrected radiographs. 3. While a large number(42.2%) of the standard radiographs showed concentric condylar position, lots of(57.8) condylar positions were retropositioned in the individually corrected radiographs. 4. The image sharpness was inferior in the individually corrected radiographs to that of the standard radiographs.