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 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*

OBJECTIVETo evaluate the positions and forms of temporomandibular joints (TMJ) with different vertical skeletal patterns in Class II division 1 patients.

METHODSCone- beam CT scans of 117 Class II division 1 adolescent patients (including 30 patients with high angle, 58 with average angle and 29 with low angle) were selected and reconstructed using Mimics 10.0 software. Fourteen measurements related to the positions and forms of condyle, forms of fossa and joint spaces were performed.

RESULTSCompared with high and average angle patients, the condyles in low angle patients located more posteriorly and inferiorly [the vertical distances between condyle and S was (20.67 ± 1.99)mm and the antero-posterior distances between condyle and S was (9.15 ± 1.61)mm]. The joint fossae were deeper [the fosse depths was (7.83 ± 1.06)mm]. The angles of posterior joint node bevels were bigger [the inclinations were (28.91 ± 3.94)° ]. The condyles were shorter, thicker, tipped more anteriorly and positioned more posteriorly [the proportions of post-positioned condyles of low angle, average angle and high angle patients were 26%, 4%, 0% respectively].

CONCLUSIONSClass II division 1 adolescents with different vertical skeletal patterns had different forms of fossae, and different positions and forms of condyles.

Adolescent ; Cone-Beam Computed Tomography ; Humans ; Malocclusion ; Malocclusion, Angle Class II ; Mandibular Condyle ; anatomy & histology ; Temporal Bone ; Temporomandibular Joint ; anatomy & histology ; diagnostic imaging

OBJECTIVEThe purpose of this study was to investigate the effects of Fränkel II appliance on the upper airway of children.

METHODSThe subjects consisted of 20 patients with Angle Class II, division I malocclusion (10 males and 10 females). The ages of all cases were ranged in 9-10 years. Each experimental subject was also served as self-control and cephalometric analysis was conducted.

RESULTSCompared with the results of pretreatment, the distance of PNS-Ba, SPP-SPPW, P-T, V-LPW and the Mcnamara line increased remarkably.

CONCLUSIONThe Fränkel II appliance can improve the sagittal dimensions of the upper airway in children.

Cephalometry ; Child ; Female ; Humans ; Male ; Malocclusion, Angle Class II ; pathology ; therapy ; Orthodontic Appliances, Functional ; Orthodontics, Corrective ; instrumentation ; Pharynx ; anatomy & histology ; Radiography ; Respiratory System ; anatomy & histology ; Skull ; diagnostic imaging

OBJECTIVETo investigate the soft and hard tissue changes in Class II division 1 patients treated with Tip-Edge plus technique.

METHODSSixteen Class II division 1 patients (7 boys and 9 girls) with mandibular retrusion in permanent dentition were selected and treated with Tip-Edge plus appliance. Lateral cephalometric films were analyzed before and after treatment. The effects were evaluated with Holdaway soft tissues analysis and routine cephalometric analysis methods. The arithmetic mean and standard deviation were calculated for each variable. Paired t-test was performed.

RESULTSThe average treatment time was 16 months. Normal overjet and overbite were established with retroclination of upper incisors and proclination of lower incisors. U1-NA(°) and U1-NA (mm) decreaed by (15.40 ± 5.31)° and (4.16 ± 1.82) mm (P < 0.01). NLA showed an average increase of (-16.60 ± 5.29)° (P < 0.01). Remarkable soft tissue change was noted after the treatment.

CONCLUSIONSThe profile in Class II division 1 patients could be quickly and efficiently improved after treatment with Tip-Edge plus technique.

Adolescent ; Cephalometry ; Child ; Esthetics, Dental ; Female ; Humans ; Male ; Malocclusion, Angle Class II ; diagnostic imaging ; therapy ; Orthodontic Wires ; Orthodontics, Corrective ; instrumentation ; methods ; Radiography, Panoramic

OBJECTIVETo compare the dental and skeletal changes in patients with Class II division 2 malocclusion treated with self-ligating and conventional bracket systems.

METHODSForty patients with Class II division 2 malocclusion were treated non-extraction. Half of them were treated with self-ligating brackets and the others were treated with conventional brackets. The dental casts and lateral cephalometric radiophotographs were analyzed before and after treatment.

RESULTSSignificant increase in inter premolar widths, arch lengths, U1-NA, L1-MP and arch perimeters were noted after orthodontic treatment in both groups. Statistically greater increase in upper inter-first premolar [(4.45 ± 2.60) mm] was found in self-ligating group than in conventional group [(2.41 ± 2.74) mm, P < 0.05]. Stepwise regression analysis indicated that the increase in arch length and arch width contributed to the increase in arch perimeter.

CONCLUSIONSThere were an overall increase in arch widths and lengths in patients treated with self-ligating and conventional bracktets. However, more arch width increase was found in self-ligating group than in conventional group.

Adolescent ; Adult ; Cephalometry ; Child ; Female ; Humans ; Male ; Malocclusion, Angle Class II ; diagnostic imaging ; therapy ; Orthodontic Brackets ; Orthodontics, Corrective ; Radiography, Dental ; Regression Analysis ; Young Adult

OBJECTIVE: To investigate the efficacy of vertical control by using conventional mini-implant anchorage in maxillary posterior buccal area for Angle class Ⅱ extraction patients. METHODS: Twenty-eight Angle class Ⅱ patients [9 males, 19 females, and age (22.6±2.8) years] were selected in this study. All of these patients were treated by using straight wire appliance with 4 premolars extraction and 2 mini-implant anchorage in maxillary posterior buccal area. In this study, the self-control method was used to measure and analyze the lateral radiographs taken before and after orthodontic treatment in each case, the main cephalometric analysis items were related to vertical changes. The digitized lateral radiographs were imported into Dolphin Imaging Software (version 11.5: Dolphin Imaging and Management Solutions, Chatsworth, California, USA), and marked points were traced. Each marked point was confirmed by two orthodontists. The same orthodontist performed measurement on the lateral radiographs over a period of time. All measurement items were required to be measured 3 times, and the average value was taken as the final measurement result. RESULTS: Analysis of the cephalometric radiographs showed that, for vertical measurements after treatment, the differences of the following measurements were highly statistically significant (P < 0.001): SN-MP decreased by (1.40±1.45) degrees on average, FMA decreased by (1.58±1.32) degrees on average, the back-to-front height ratio (S-Go/N-Me) decreased by 1.42%±1.43% on average, Y-axis angle decreased by (1.03±0.99) degrees on average, face angle increases by (1.37±1.05) degree on average; The following measurements were statistically significant (P < 0.05): the average depression of the upper molars was (0.68±1.40) mm, and the average depression of the upper anterior teeth was (1.07±1.55) mm. The outcomes indicated that there was a certain degree of upper molar depression after the treatment, which produced a certain degree of counterclockwise rotation of the mandibular plane, resulting in a positive effect on the improvement of the profile. CONCLUSION The conventional micro-implant anchorage in maxillary posterior buccal area has a certain vertical control ability, and can give rise to a certain counterclockwise rotation of the mandible, which would improve the profile of Angle Class Ⅱ patients.
Bicuspid ; Cephalometry/methods* ; Female ; Humans ; Male ; Malocclusion, Angle Class II/therapy* ; Mandible ; Maxilla/diagnostic imaging* ; Orthodontic Anchorage Procedures ; Tooth Movement Techniques ; Vertical Dimension

OBJECTIVETo explore the feasibility of surgical design for mandibular retrusion using three-dimensional software.

METHODSThree-dimensional reconstruction was performed by Mimics software based on the preoperative CT data. The model of the maxillofacial region was imported into Rapidform software for measuring the associated parameters and Geomagic software for simulation of osteotomy. The reliability of the virtual operation was validated during the surgery.

RESULTSThe model of mandibular retrusion was reconstructed and successfully used to simulate the surgery. The simulation result was applied in subsequent actual surgery and good surgical outcomes were achieved.

CONCLUSIONThe three-dimensional software can be used to simulate the surgery for mandibular retrusion and improve the predictability and accuracy of the surgery.

Computer Simulation ; Feasibility Studies ; Humans ; Image Processing, Computer-Assisted ; methods ; Imaging, Three-Dimensional ; methods ; Male ; Malocclusion, Angle Class II ; surgery ; therapy ; Mandible ; abnormalities ; diagnostic imaging ; surgery ; Maxilla ; diagnostic imaging ; Models, Anatomic ; Retrognathia ; diagnostic imaging ; surgery ; Software ; Surgery, Computer-Assisted ; methods ; Tomography, X-Ray Computed ; Young Adult