OBJECTIVES: The aim of this study was to compare the anterior and posterior occlusal plane characteristics of patients with different temporomandibular joint osseous statuses. METHODS: A total of 306 patients with initial cone beam CT (CBCT) and cephalograms were included. They were divided into three groups on the basis of their temporomandibular joint osseous status: bilateral normal (BN) group, indeterminate for osteoarthrosis (I) group, and osteoarthrosis (OA) group. The anterior and posterior occlusal planes (AOP and POP) of the different groups were compared. Then, the regression equation was established after adjusting for confounding factors, and a correlation analysis between the occlusion planes and other parameters was performed. RESULTS: SNA, SNB, FMA, SN-MP, Ar-Go, and S-Go were correlated with the occlusal planes. Relative to the BN and I groups, the FH-OP of the OA group increased by 1.67° on the average, FH-POP increased by 1.42° on the average, and FH-AOP increased by 2.05° on the average. CONCLUSIONS The occlusal planes were steeper in the patients with temporomandibular osteoarthrosis than in the patients without it, and the mandible rotated downward and backward. The height of the mandibular ramus, the mandibular body length, and the posterior face height were small. In clinical practice, attention should be given to the potential risk of temporomandibular joint osteoarthrosis in such patients. In addition, SNB, FMA, SN-MP, Ar-Go, S-Go, and occlusal planes had moderate correlations.
Humans ; Dental Occlusion ; Cephalometry ; Mandible ; Temporomandibular Joint Disorders/diagnostic imaging* ; Temporomandibular Joint/diagnostic imaging* ; Osteoarthritis/diagnostic imaging* ; Mandibular Condyle

Objective:To investigate the relationship between idiopathic condylar resorption （ICR） and arch width disorder. Methods:Thirty-two patients with ICR and twenty patients without condylar resorption were enrolled according to the same inclusion criteria. They were divided into experimental group and control group. The experimental group was divided into unilateral ICR group and bilateral ICR group according to the affected side of condylar resorption, and then experimental group was divided into subgroups ICR Ⅰ, ICRⅡand ICR Ⅲ according to the degree of condylar resorption. Patients with no condylar resorption were used as a control group. The width of anterior, middle and posterior segments of dental arch on cone beam computed tomography（CBCT） was measured and the two groups of measured values were statistically analyzed. Results:Compared with the control group, the width of maxillary anterior, middle and posterior segments in ICR group was significantly reduced, and the difference was statistically significant（P<0.01）. But the width of mandibular segment was not significantly different from that in control group（P>0.05）. There was no significant difference in the width of anterior, middle and posterior dental arch between subgroups（P>0.05）. Conclusion:Almost all patients with ICR have malocclusion of maxillary and mandibular arch width, but there is no significant correlation between the malocclusion width and the severity of condylar resorption.
Humans ; Mandibular Condyle/diagnostic imaging* ; Dental Arch ; Bone Resorption ; Mandible ; Malocclusion

Objective: To investigate the shape and position changes of temporomandibular joint (TMJ) in adult skeletal class Ⅱ malocclusion with high angle patients after vertical mandibular control, and the correlation between vertical mandibular changes and condylar position changes. Methods: Twenty adult skeletal class Ⅱ malocclusion with high angle patients [6 males and 14 females, aged (21.4±2.4) years] who underwent extraction treatment and active vertical control in the Department of Orthodontics, Lanzhou University Stomatological Hospital from October 2017 to November 2020 were selected. Cone-beam CT data of the patient before and after treatment were imported into Invivo Dental 5.0 software for three-dimensional reconstruction and correction, and the vertical index of mandible in reconstructed lateral cephalogram (mandibular plane angle, posterior anterior height ratio, mandibular true rotation angle) were measured. Incisal angle and variables of condyle shape, position and articular fossa shape were measured. Paired t test was performed on the results before and after treatment, and the correlation between mandibular vertical changes and condylar position changes was determined by Pearson correlation coefficient calculation. Results: After treatment, the overbite and overjet were within normal range, and the vertical height of the molars was controlled. Compared with the measurement before treatment, mandibular plane angle and mandibular true rotation angle were decreased by 2.05°±1.22° (t=7.60, P<0.001) and 1.42°±1.92° (t=3.54, P=0.002), respectively. The posterior anterior height ratio was increased by (1.89±3.32)% (t=2.56, P=0.019). After treatment, the mediolateral diameter of condyle, the anteroposterior diameter of condyle, the maximum cross-sectional area of condyle, the height of condyle head, the width of articular fossa, the depth of articular fossa and the articular nodular angle were increased by (0.55±0.76) mm (t=-2.73, P=0.015), (0.27±3.51) mm (t=-3.23, P=0.006), (6.01±7.36) mm² (t=-2.80, P=0.013), (0.33±0.72) mm (t=-2.14, P=0.046), (0.56±0.93) mm (t=-2.37, P=0.032), 0.33 (0.14, 0.51) mm (Z=-2.76, P=0.006) and 1.50°±2.40° (t=-2.44, P=0.028), respectively. The internal condylar space and the external condylar space were decreased by (0.33±0.49) mm (t=2.31, P=0.035) and (0.20±0.23) mm (t=3.58, P=0.003), respectively. Before orthodontic treatment, 6 patients were with anterior displacement of the condyle, 7 patients with central position of the condyle, and 7 patients with posterior displacement of the condyle. After correction, patients who were with central position of the condyle have not changed much. The posterior displaced condyle in 2 patients and anterior displaced condyle in 3 patients became in central position after treatment. The joint space index was closer to the central position in 3 patients with anterior displacement and 3 patients with posterior displacement. The position of condyle in 1 patient with posterior displacement and 1 patient with anterior displacement remained basically unchanged. There was a significant negative correlation between the change of the posterior-anterior height ratio and the change of the internal condylar space in patients (r=-0.52, P=0.019), and a low correlation with the contral condylar space and the external condylar space(r=-0.48, P=0.031; r=-0.47, P=0.035). Conclusions: Skeletal class Ⅱ malocclusion with high angle adult patients achieved normal overbite and overjet and remodeling of condyle and articular fossa occurred after orthodontic treatmnet and vertical control. There was a certain negative correlation between the change of posterior-anterior height ratio and the change of condylar position.
Adult ; Female ; Humans ; Male ; Cone-Beam Computed Tomography ; Malocclusion, Angle Class II/diagnostic imaging* ; Mandible/diagnostic imaging* ; Mandibular Condyle/diagnostic imaging* ; Overbite ; Temporomandibular Joint/diagnostic imaging*

Objective: To observe the different imaging manifestations of condylar sclerosis in temporomandibular joint osteoarthrosis and explore the imaging significance of condylar sclerosis. Methods: From January 2018 to December 2020, 50 patients with temporomandibular joint condylar sclerosis were examined by cone-beam CT (CBCT) and underwent spiral CT, MRI and radionuclide bone imaging at the Department of Oral and Maxillofacial Surgery in General Hospital of Chinese PLA. There were 15 males and 35 females aged from 16 to 65 years with age of (42.7±14.5) years. The imaging manifestations of CBCT, spiral CT, MRI and radionuclide bone imaging, joint disc displacement and abnormal bone metabolism of condylar sclerosis were analyzed. And the area of condylar sclerosis was graded according to the image of CBCT. Results: A total of 50 patients were included, including 38 unilateral condylar sclerosis, 12 patients with bilateral condylar sclerosis, the total condylar sclerosis were 66. There was no significant difference between the detection rate of further spiral CT (95.5%, 63/66) and CBCT (100.0%, 66/66) (corrected χ²=1.36,P=0.244). The area of condylar sclerosis was (35.5±4.5) mm², ranged from 1 to 100 mm². In addition, spiral CT showed more clearly condylar sclerosis than CBCT. Sclerosis can occur in all parts of condyle, mainly in the upper middle region (68.2%,45/66) in coronal position and in the upper front region (71.2%,47/66) in sagittal position. Fifty-seven condylar sclerosis were detected by MRI, including 4(4/19) condylar sclerosis less than 4 mm². There was significant difference in the displacement of temporomandibular joint disc between the sclerotic side and the non sclerotic side (χ²=10.09, P=0.006). MRI display the condylar sclerosis showed low signal (56/62), followed by high signal (5/62) and medium signal (1/62). Radionuclide bone imaging showed that 4 of the 38 patients with unilateral condyle sclerosis had symmetrical bone metabolism, 34 had abnormal bone metabolism, and 21 patients had concentrated on the non-sclerotic side. Radionuclide bone imaging showed that 4 of the 38 patients with unilateral condyle sclerosis had symmetrical bone metabolism and 34 had abnormal bone metabolism. Conclusions: Spiral CT is more accurate than CBCT in terms of condyle sclerosis through different imaging analysis, and the detection rate of both is higher than MRI. Most of condylar sclerosis showed different degrees of low signal on MRI. The condylar sclerosis side is usually manifested by abnormal bone metabolism.
Male ; Female ; Humans ; Mandibular Condyle/diagnostic imaging* ; Sclerosis/diagnostic imaging* ; Temporomandibular Joint/diagnostic imaging* ; Temporomandibular Joint Disorders/etiology* ; Temporomandibular Joint Disc/diagnostic imaging* ; Cone-Beam Computed Tomography ; Temporomandibular Joint Dysfunction Syndrome ; Osteoarthritis/etiology* ; Magnetic Resonance Imaging

Objective: To investigate the imaging features of condylar cystic degeneration of temporomandibular joint (TMJ) by cone-beam CT (CBCT), spiral CT, MRI and radionuclide bone imaging. Methods: From January 2018 to December 2020, thirty-two patients with cyst-like lesions of condylein temporomandibular joint were examined by CBCT, spiral CT, MRI and radionuclide bone imaging at the Department of Oral and Maxillofacial Surgery in General Hospital of Chinese PLA. There were 12 males and 20 females involved, aged from 16 to 65 years with an average age of (33.9±12.5) years. The characteristics of CBCT, spiral CT, MRI and radionuclide bone imaging were analyzed. Condylar cyst like lesions were classified as type A and type B based on the presence or absence of surface bone defects. Condylar cyst like lesions were classified as type Ⅰ(yes) and type Ⅱ(no) according to the accompanying bone marrow edema-like lesions of the condyles. The incidence of condylar bone marrow edema, disc displacement and abnormal bone metabolism were analyzed. Results: A total of 64 joint images of 32 patients were included, including 34 sides with TMJ cyst-like lesion and 6 sides with multiple cyst-like lesions,the total cyst-like lesions were 42. The largest diameter of cyst-like lesion ranged from 1.0 to 12.4 mm, with an average length of (3.7± 1.8) mm. There were 24 cases of type A TMJ cyst like lesion and 10 cases of type B cyst-like lesion. The detection rate of CBCT was 95.2% (40/42) and that of spiral CT was 100% (42/42), there was no significant difference (Calibration Chi-square=0.51, P=0.474). The detection rate of nuclear magnetic resonance was 80.1% (34/42), and the detection rate of cyst-like lesions less than 2 mm was 3/11. In the cyst like lesion side, there were 9 sides with anterior disc displacement with reduction, 20 sides with anterior disc displacement without reduction. In the non-cyst like lesion side, 10 sides with anterior disc displacement with reduction and 6 sides with anterior disc displacement without reduction. There was a significant difference in the displacement of the disc between cyst-like and non-cystic lesion side (χ²=7.80, P=0.005). MRI showed that 6 cases of cystic side[17.6% (6/34)] had bone marrow edema-like lesions (all type A), 1 case of non-cyst like lesions side [3.3% (1/30)] had bone marrow edema-like lesion, there was no significant difference between cystic and non-cystic lesions (Calibration Chi-square=2.04, P=0.153). There was a significant difference between type A and B cystic lesions (Fisher exact probability method, P=0.024). Radionuclide bone imaging showed abnormal bone metabolism in 26 patients in the cyst-like lesion side and 5 patients in the non-cyst like lesion side (χ²=22.82, P<0.001). Conclusions Multi-slice Spiral CT could detect the cyst-like lesion of TMJ condyle in the early stage, which is different from the large joint. And the formation mechanism may vary from the different classifications.
Adolescent ; Adult ; Aged ; Cysts ; Female ; Humans ; Joint Dislocations ; Magnetic Resonance Imaging ; Male ; Mandibular Condyle/diagnostic imaging* ; Middle Aged ; Multimodal Imaging ; Temporomandibular Joint/diagnostic imaging* ; Temporomandibular Joint Disc ; Temporomandibular Joint Disorders/diagnostic imaging* ; Young Adult

OBJECTIVE: To analyze the biomechanical mechanism of mandibular symphyseal fracture combined with bilateral intracapsular condylar fractures using finite element analysis (FEA). METHODS: Maxillofacial CT scans and temporomandibular joint (TMJ) MRI were performed on a young male with normal mandible, no wisdom teeth and no history of TMJ diseases. The three-dimensional finite element model of mandible was established by Mimics and ANSYS based on the CT and MRI data. The stress distributions of mandible with different angles of traumatic loads applied on the symphyseal region were analyzed. Besides, two models with or without disc, two working conditions in occlusal or non-occlusal status were established, respectively, and the differences of stress distribution between them were compared. RESULTS: A three-dimensional finite element model of mandible including TMJ was established successfully with the geometry and mechanical properties to reproduce a normal mandibular structure. Following a blow to the mandibular symphysis with different angles, stress concentration areas were mainly located at condyle, anterior border of ramus and symphyseal region under all conditions. The maximum equivalent stress always appeared on condylar articular surface. As the angle between the external force and the horizontal plane gradually increased from 0° to 60°, the stress on the mandible gradually concentrated to symphysis and bilateral condyle. However, when the angle between the external force and the horizontal plane exceeded 60°, the stress tended to disperse to other parts of the mandible. Compared with the condition without simulating the disc, the stress distribution of articular surface and condylar neck decreased significantly when the disc was present. Compared with non-occlusal status, the stress on the mandible in occlusal status mainly distributed on the occlusal surface, and no stress concentration was found in other parts of the mandible. CONCLUSION When the direction of external force is 60° from the horizontal plane, the stress distribution mainly concentrates on symphyseal region and bilateral condylar surface, which explains the occurrence of symphyseal fracture and intracapsular condylar fracture. The stress distribution of condyle (including articular surface and condylar neck) decreases significantly in the presence of arti-cular disc and in stable occlusal status when mandibular symphysis is under traumatic force.
Finite Element Analysis ; Humans ; Male ; Mandible ; Mandibular Condyle/diagnostic imaging* ; Mandibular Fractures/diagnostic imaging* ; Stress, Mechanical ; Temporomandibular Joint/diagnostic imaging* ; Temporomandibular Joint Disorders

OBJECTIVE: To compare temporomandibular joint (TMJ) morphology and position among skeletal class Ⅱ female adolescents with different vertical patterns using cone-beam CT (CBCT). METHODS: Diagnostic CBCT images of 80 female patients aged 11 to 14 years were assessed retrospectively. According to subspinale-nasion-supramental angle (ANB) and Frankfort horizontal plane-gonion-gnathion angle (FH-GoGn), the participants were categorized into four groups (20 subjects each), i.e. class Ⅰ normal angle (group 1, 0°≤ANB < 4°, 22°≤FH-GoGn≤32°), class Ⅱ low (group 2, ANB≥4°, FH-GoGn < 22°), normal (group 3, ANB≥4°, 22°≤FH-GoGn≤32°) and high angle (group 4, ANB≥4°, FH-GoGn > 32°). Cephalometrics, morphology and position of TMJ were measured in Dolphin software. Using paired-samples t test to analyze TMJ symmetry, One-way analysis of variance (One-way ANOVA) and Chi-square tests to detect differences among the groups. The correlations between cephalometrics and TMJ measurements were also analysed within the skeletal class Ⅱ patients. RESULTS: (1) Analysing TMJ morphologic symmetry, some measurements differed statistically although the mean diffe-rences were negligibly relative to their values. No statistically significant difference was found among the groups though group 4 showed the highest probability of condylar position asymmetry (65%). (2) Comparing group 1 with group 3, statistical difference was found in condylar position (χ²=6.936, P < 0.05) instead of morphologic measurements. Anterior and concentric condylar position were more frequently observed in group 1, yet posterior position was more prevalent in group 3. (3) In groups 2, 3, and 4, statistically, group 2 had the deepest glenoid fossa depth (H_2&4=10.517, P=0.002), biggest superior (LSD-t_2&3=3.408, LSD-t_2&4=5.369, P < 0.001) and lateral (LSD-t_2&3=2.767, LSD-t_2&4=3.350, P=0.001) joint spaces, whereas group 4 showed the shortest condylar long axis diameter (H_2&4=13.374, P < 0.001), largest glenoid fossa vertical distance (LSD-t_2&4=4.561, P < 0.001, LSD-t_3&4=2.713, P=0.007), smallest medial (LSD-t_2&4=-4.083, P < 0.001) and middle (LSD-t_2&4=-4.201, P < 0.001) joint spaces. The posterior condylar position proportion gradually increased from groups 2 to 3 to 4. Correlation analysis revealed ANB correlated with anterior joint space positively (r=0.270, P=0.037) and condylar long axis angle negatively (r=-0.296, P=0.022). FH-GoGn correlated with superior (r=-0.488, P < 0.001), posterior (r= -0.272, P=0.035), mesial (r=-0.390, P=0.002), middle (r=-0.425, P=0.001), and lateral (r=-0.331, P=0.010) joint spaces, articular eminence inclination (r=-0.259, P=0.046), as well as condylar long axis diameter (r=-0.327, P=0.011) negatively, and glenoid fossa depth (r=0.370, P=0.004) positively. CONCLUSION TMJ characteristics of skeletal class Ⅱ sagittal pattern mainly reflected in condylar position rather than morphology. TMJs of different vertical patterns differed more in joint spaces, position of condyle and glenoid fossa than in morphologic measurements. Vertical position of glenoid fossa and proportion of posterior condyle increased gradually from hypodivergent to hyperdivergent. Highest glenoid fossa position, maximum ratio of posterior positioned condyle, smallest joint spaces, shallowest glenoid fossa depth, and narrowest condylar long axis diameter were found in skeletal class Ⅱ high angle group, which means that patients with this facial type have considerable joint instable factors, and we should especially pay attention when orthodontic treatment is carried out on them.
Adolescent ; Cephalometry ; Child ; Cone-Beam Computed Tomography ; Female ; Humans ; Malocclusion, Angle Class II/diagnostic imaging* ; Mandibular Condyle/diagnostic imaging* ; Retrospective Studies ; Temporomandibular Joint/diagnostic imaging*

OBJECTIVE: To analyze the radiological characteristics and classifications of the cyst-like lesion of condyle in temporomandibular joint (TMJ) by cone beam computed tomography (CBCT). METHODS: The study was conducted retrospectively on TMJ images from 194 patients who underwent CBCT examinations. Location, size, amount, surrounding bone trabecula, cortical bone white line of cyst-like lesion, and the overall condition of the condylar bone were evaluated. According to the overall condition of the condylar bone, the cyst-like lesion of condyle were divided into typesⅠand Ⅱ. The location, size, amount, surrounding bone trabecula, and cortical bone white line of the two types of cyst-like lesions were compared. RESULTS: In 198 condylars of 194 patients, cyst-like lesions were detected in the left side of 94 patients, in the right of 96 patients, and in both sides of 4 patients. The size of lesions ranged from 1.2 mm to 13.5 mm, with an average size of (3.4±1.5) mm. Half of the cyst-like lesions were located underneath the anterior lateral cortical bony layer (99 condylars, 50.0%). Most cyst-like lesions were solitary (149 condylars, 75.3%), while 62.6% (124 condylars) were surrounded by continuous bony white lines. Bone sclerosis could be observed in 160 condylars (80.8%). A total of 132 condyles (66.7%) were accompanied by changes in late-stage osteoarthrosis, while the others were only accompanied by early-stage osteoarthrosis (10 osteoarthrosis, 5.1%) or showed no evidence of osteoarthrosis (56 osteoarthrosis, 28.3%). Statistical difference were observed in the location, amount, and surrounding bone trabecula of the two types of cyst-like lesions. TypeⅠcyst-like lesions had more frequent and bone sclerosis than type Ⅱ, whereas type Ⅱ cyst-like lesions occurred more on condylar internal or condyle neck than typeⅠ. CONCLUSIONS The pathogenesis and mechanism of the two types of cyst-like lesions may be different from each other.
Cone-Beam Computed Tomography ; Cysts ; diagnostic imaging ; Humans ; Mandibular Condyle ; diagnostic imaging ; Retrospective Studies ; Temporomandibular Joint ; diagnostic imaging ; Temporomandibular Joint Disorders ; diagnostic imaging

To investigate three-dimensional morphological features of temporomandibular joint in skeletal malocclusion Class III with different vertical skeletal facial types.
 Methods: A total of 46 adults with skeletal malocclusion Class III were enrolled and allocated into a normal-angle, a high-angle and a low-angle groups. All patients were undergone cone beam computed tomography (CBCT). Images of temporomandibular joint were reconstructed and analyzed by Invivo 5. Nine measurements relevant to the positions and forms of condyle as well as joint spaces were performed.
 Results: Significant differences were not observed between the 2 sides of each group among skeletal malocclusion Class III (P>0.05). Compared with the high-angle and normal-angle patients, the low-angle patients had larger superior spaces, bigger gradients of the articular tublecle, longer condyle, and larger internal spaces between the condyle and the fossa. Compared with the low-angle and normal-angle patients, the high-angle patients had smaller condylar antero-posterior diameters.
 Conclusion: Class III malocclusion patients with different vertical skeletal patterns have different positions and forms of condyles, which should be paid attention to in clinic.
Adult ; Cone-Beam Computed Tomography ; Face ; diagnostic imaging ; Humans ; Image Processing, Computer-Assisted ; Malocclusion, Angle Class III ; diagnostic imaging ; Mandibular Condyle ; diagnostic imaging ; Temporomandibular Joint ; diagnostic imaging

PURPOSE: This study was performed to compare the condylar position in patients with temporomandibular joint disorders (TMDs) and a normal group by using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: In the TMD group, 25 patients (5 men and 20 women) were randomly selected among the ones suffering from TMD according to the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). The control group consisted of 25 patients (8 men and 17 women) with normal temporomandibular joints (TMJs) who were referred to the radiology department in order to undergo CBCT scanning for implant treatment in the posterior maxilla. Linear measurements from the superior, anterior, and posterior joint spaces between the condyle and glenoid fossa were made through defined landmarks in the sagittal view. The inclination of articular eminence was also determined. RESULTS: The mean anterior joint space was 2.3 mm in the normal group and 2.8 mm in the TMD group, respectively. The results showed that there was a significant correlation between the superior and posterior joint spaces in both the normal and TMD groups, but it was only in the TMD group that the correlation coefficient among the dimensions of anterior and superior spaces was significant. There was a significant correlation between the inclination of articular eminence and the size of the superior and posterior spaces in the normal group. CONCLUSION: The average dimension of the anterior joint space was different between the two groups. CBCT could be considered a useful diagnostic imaging modality for TMD patients.
Cone-Beam Computed Tomography ; Diagnostic Imaging ; Humans ; Joints ; Male ; Mandibular Condyle ; Maxilla ; Temporomandibular Joint ; Temporomandibular Joint Disorders*