Temporomandibular Joint Position Research Articles

Correlations of temporomandibular joint morphology and position using cone-beam computed tomography and dynamic functional analysis in orthodontic patients: A cross-sectional study.

To correlate temporomandibular joint (TMJ) morphology and position with cone-beam computed tomography (CBCT) images, Joint Vibration Analysis (JVA), and Jaw Tracker (JT) to develop a radiation-free, dynamic method for screening and monitoring the TMJ in orthodontic patients. A total of 236 orthodontic patients without symptoms of TMJ disorders who had undergone CBCT were selected for the JVA and JT tests in this cross-sectional study. TMJ position and morphology were measured using a three-dimensional analysis software. JT measurements involved six opening-closing cycles, and JVA measurements were performed using a metronome to guide the mouth opening-closing movements of the patients. The correlations among the three measuring devices were evaluated. Abnormalities in condylar surface morphology affected the mandibular range of motion. The cut-off value results show that when various measurement groups are within a certain range, abnormalities may be observed in morphology (area under the curve, 0.81; P < 0.001). A 300/< 300 Hz ratio ≥ 0.09 suggested abnormal morphology (P < 0.05). Correlations were observed among the maximum opening velocity, maximum vertical opening position, and joint spaces in the JT measurements. Correlations were also observed between the > 300/< 300 Hz ratio, median frequency, total integral, integral < 300 Hz, and peak frequency with joint spaces in the JVA measurements. JT and JVA may serve as rapid, non-invasive, and radiation-free dynamic diagnostic tools for monitoring and screening TMJ abnormalities before and during orthodontic treatment.

Efficacy of scapulothoracic exercises on proprioception and postural stability in cranio-cervico-mandibular malalignment: A randomized, double-blind, controlled trial.

Cranio-cervico-mandibular (CCM) malalignment is associated with forward head posture (FHP) and temporomandibular joint (TMJ) disorders and affects masticatory muscles. This randomized, double-blind controlled trial aimed to compare the efficacy of scapula-thoracic (ST) exercises on temporomandibular and cervical joint position sense and postural stability in individuals with CCM malalignment. Fourty-nine participants with CCM malalignment were randomly assigned to the ST exercise group (STEG, n= 24) or the control group (CG, n= 25). STEG included progressive strengthening, proprioceptive, and stabilization exercises. All participants were assessed before treatment, at the end of the 8th week treatment period and at the 12th week post-treatment follow-up. Cranio-vertebral angle measurement, Fonseca's Questionnaire, Helkimo Clinical Dysfunction Index, TMJ position test, cervical joint position error test and postural stability assessment were used. The TMJ and cervical joint position sense, total sway degree, area gap percentage, sway velocity and antero-posterior body sway results showed significant improvement in the STEG compared to the CG (p< 0.05), however medio-lateral body sway did not differ between groups (p> 0.05). Postural stability, TMJ and cervical joint position sense appear to be affected in individuals with CCM malalignment. Our results showed that an exercise program including ST stabilization, proprioception and strengthening of the scapular muscles may be effective in the management of CCM malalignment and will allow clinicians to plan holistic treatment.

The short- and long-term effects of congenital occlusion loss of the unilateral first permanent molar on the temporomandibular joint morphology and position: A retrospective study based on cone-beam computed tomography.

To investigate the effects of congenital unilateral first permanent molar occlusal loss (CUMOL) on the morphology and position of temporomandibular joint (TMJ). Cone-beam computed tomography (CBCT) images of 37 patients with CUMOL (18 males and 19 females, mean age: 13.60 ± 4.38 years) were divided into two subgroups according to the status of second molar (G1: the second molar not erupted, n = 18, G2: second molar erupted, n = 19). The control group consisted of 33 normal occlusion patients (9 males and 24 females, mean age: 16.15 ± 5.44 years) and was divided into 2 subgroups accordingly (G3: the second molar had not erupted, n = 18, G4: the second molar had erupted and made contact with the opposing tooth, n = 15). Linear and angular measurements were used to determine the characteristics of TMJ. In G1, the condyle on the side of the CUMOL shifts posteriorly, with significant side differences observed in Anterior space (AS, P < .05) and Posterior space (PS, P < .05). However, with the eruption of the second permanent molars, in G2, the condyle on the CUMOL side moves posteriorly and inferiorly. This results in significant lateral differences in the AS (P < .05), PS (P < .05), and Superior space (SS, P < .05). Additionally, there is an increase in the thickness of the roof of the glenoid fossa (TRF) on the CUMOL side (P < .05), and a decrease in the inclination of the bilateral articular eminences (P < .05). CUMOL can affect the position and the morphology of the condyle and was associated with the eruption of the second permanent molars. Before the eruption of the second permanent molars, CUMOL primarily affects the position of the condyle. After the emergence of the second permanent molars, CUMOL leads to changes in both the condyle's position and the morphology of the glenoid fossa.

Three-dimensional analysis of mandibular morphology asymmetry and temporomandibular joint position in patients with unilateral Brodie bite.

Previous studies have shown unilateral posterior crossbite is associated with mandibular asymmetry in morphology and position. However, it remains unclear whether unilateral Brodie bite plays a similar role in mandibular development. Therefore, this study aims to investigate the morphological and positional symmetry of mandibles in patients with unilateral Brodie bite by three-dimensional anaylsis. Fourteen patients with unilateral Brodie bite (mean age 18.43 ± 4.24 years) and fourteen sex- and age-matched patients with normal occlusion (mean age 18.07 ± 5.48 years) underwent cone-beam computed tomography (CBCT) scans. 3D surface mesh models of their mandibles were established using Mimics Research 19.0. The surface matching percentage was compared between the original and mirrored mandible by Geomagic Control X software. Furthermore, the dimension and position of the temporomandibular joint (TMJ) were determined for both groups using InVivoDental 5.0. For surface-to-surface deviation analysis, the percentage of mismatch in patients with unilateral Brodie bite was significantly higher than the control group at ±0.50 mm, ±0.75 mm, and ±1.00 mm tolerance (P < .001). In patients with unilateral Brodie syndrome, the condyles on the scissors-bite side showed a significantly more anterior position (P = .03), greater medial inclination (P < .01), and larger posterior TMJ space (P = .01) than the non-scissors-bite side. Patients with unilateral Brodie bite exhibit a more asymmetrical mandibular morphology, with a greater anterior condylar position and posterior joint space on the scissors-bite side, indicating that early diagnosis and treatment may be necessary for patients with unilateral Brodie bite.

Is proprioception affected in those with persistent intra-articular temporomandibular disorders? A cross-sectional study exploring joint position sense and force sense of the jaw

BackgroundProprioception is an important component of normal jaw function, although to date it is unknown if and how proprioception is affected in those with intra-articular temporomandibular disorders (IA-TMDs). This challenges effective management of this subgroup. ObjectivesDetermine whether differences in local joint position sense and force sense exist between individuals with IA-TMD and those without a jaw problem. DesignCross-sectional study. MethodSixty age and sex matched participants were recruited (n = 30 IA-TMD, n = 30 healthy controls). Temporomandibular joint position sense was tested to one target (50% of maximal mouth opening) using a ruler. Temporomandibular force sense was tested to two targets (50% and 70% of maximal molar pain-free bite force) using a bite sensor. Constant, absolute and variable errors were calculated for each outcome and compared between groups using p-values and 95% confidence intervals for effect size (d). ResultsSignificantly greater degrees of constant, absolute and variable error were seen for force sense testing at the 50% target (p < 0.05). No statistically significant difference was observed between groups for joint position sense, or for constant or variable force sense error at the 70% target (p > 0.05). Despite this, all joint position sense and force sense measures demonstrated possible clinical significance (upper limits 95% CI d ≥ 0.5). ConclusionsForce sense, particularly at lower levels, appears impaired in those with IA-TMD. Joint position sense and force sense at higher levels appear less affected, although may still be important to consider in the management of IA-TMD in some patients.

Evaluation of the relationship between the attachment type of lateral pterygoid muscle and the position of temporomandibular joint disc in patients with temporomandibular joint disorders based on wireless amplified MRI detector high resolution imaging

Objective: To explore the correlation between the attachment type of lateral pterygoid muscle (LPM) and the position of temporomandibular joint (TMJ) disc in patients with temporomandibular disorders (TMD) by using wireless amplified magnetic resonance imaging detector (WAND) coupled with conventional head and neck joint coil for high resolution imaging of TMJ. Methods: Eighty-five patients with TMD diagnosed by oral and maxillofacial surgeons of Guizhou Provincial People's Hospital from October 2019 to January 2022 were collected. A total of 160 TMJ were included. There were 16 males and 69 females, aged (32.7±14.2) years. All patients were scanned with open, closed oblique sagittal and coronal WAND coupled head and neck coils with bilateral TMJ. Based on TMJ and LPM high resolution imaging, to explore the correlation between LPM attachment types and the position of TMJ disc in TMD patients, and to evaluate the potential clinical value of LPM attachment types in TMD patients. χ2 test and Pearson correlation analysis were used to evaluate the correlation between LPM attachment type and TMJ disc location. Results: There were three types of LPM attachment: type Ⅰ in 51 cases [31.9% (51/160)], type Ⅱ in 77 cases [48.1% (77/160)] and type Ⅲ in 32 cases [20.0% (32/160)]. There was a significant correlation between the type of LPM attachment and the position of articular disc (χ2=28.20, P=0.002, r=0.776). There was no statistical significance between the type of LPM attachment and the reversible displacement of articular disc (χ2=0.24, P=0.887, r=0.825). Conclusions: There is a correlation between the attachment type of LPM and the position of the disc in TMD patients. WNAD coupled with conventional head and neck joint coil TMJ high resolution scan can provide reliable imaging evidence for TMD patients in evaluating the type of LPM attachment and the location of disc.

Comprehensive positional and morphological assessments of the temporomandibular joint in adolescents with skeletal Class III malocclusion: a retrospective CBCT study

BackgroundCondyle-fossa relationships in adolescents with skeletal Class III malocclusion remain unclear. Therefore, this study used cone-beam computed tomography (CBCT) to evaluate the position and morphology of the temporomandibular joint (TMJ) in adolescents with skeletal Class III malocclusion.MethodsIn this cross-sectional retrospective study, CBCT images from 90 adolescents with skeletal Class III malocclusion and 30 controls were analysed. Adolescents with skeletal Class III malocclusion were divided into different groups based on (1) sex (male and female), (2) sides (right and left), (3) age (early, middle, and late adolescence), and (4) vertical skeletal patterns (hyperdivergent, normodivergent, and hypodivergent). Morphology of the condyle and fossa as well as condylar position, was compared among groups. Data were collected and submitted for statistical analysis. This study adheres to STROBE guidelines.ResultsRegarding the intergroup comparisons, there were significant differences in TMJ position and morphology between the skeletal Class III malocclusion with different vertical skeletal patterns and control groups (P < 0.05). Within groups, condyle-fossa relationships differed significantly according to sex, age, and vertical skeletal patterns (P < 0.05); however, the mean values were not statistically different between left and right sides in adolescents with skeletal Class III malocclusion.ConclusionsOur findings can be used clinically and radiographically to evaluate the condyle and glenoid fossa features in adolescents with skeletal Class III malocclusion, providing a basis for better TMD diagnosis and orthodontic treatment.

Technique for assessing the position of temporomandibular joint

With the development of new technologies of X-ray diag-nostics, various methods of their application are used in modern dentistry. Cone beam computed tomography (CBCT) is mainly used to visualize the bone structures of the skull — temporomandibular joint, structures of the upper and lower jaw, the location of teeth in bone tissue for further use of reconstructed three-dimensional models for digital treatment planning and prediction of results. Aim of the study: technique of three-dimensional analysis of the parameters of the temporomandibular joint (TMJ) optimization, possible deviations analysis. Materials and methods: computed tomography data was obtained and an assessment of compliance with the neces sary criteria was carried out in the Ez3D Plus software (Vatech, Korea). A three-dimensional analysis technique of the individual position of the condyle in the articular fossa was provided with use of Mimics software (Materialise, Belgium), based on the data acquired from computed tomography (CT) re-search. The accuracy of positioning of three-dimensional models of dentition on segmented models from comput-ed tomography was evaluated. By a certain algorithm of actions, the segmented model was moved to the position corresponding to the central occlusion. Results. The study showed that the main reason for the inaccuracy of multi-stage positioning of the mandible are the automatic algo-rithms of model matching and poor detail of computed tomography sli ces. In this regard, zoning of the compared model’s parts was used, which demonstrated its effective-ness and result’s stability. The greatest inaccuracy of the results of measuring the position of the TMJ is associated with the quality of CT and manual correction of masks and contours of the surfaces of condyles. The algorithm was developed for obtaining the necessary information when assessing the position of the condyles before planning the orthodontic treatment. Conclusion. А reasonable tech-nique for constructing condyle contours in central occlu-sion has been determined, which can be used as a basis for positioning the mandible in a digital orthodontic treat-ment planning.

Evaluation of condyle-fossa relationships in skeletal Class I malocclusion with variable degrees of deep overbite and open bite

ABSTRACT Objective To compare the temporomandibular joint (TMJ) position and shape between skeletal Class I subjects with different degrees of deep overbite or open bite and unaffected peers. Methods Cone beam computed tomography (CBCT) images of 90 participants, equally divided into deep bite, open bite, and control groups (DBG, OBG, and CG, respectively), were analyzed. The DBG and OBG were further subdivided into three subgroups based on the severity. Linear and angular measurements were used to determine the positional and morphological characteristics of the TMJ. Results DBG showed significantly larger superior joint space, anterior inclination of the condyle, and articular eminence inclination than CG and OBG. The severity of deep bite and open bite significantly influenced the TMJ position and morphology. Conclusion In severe deep overbite and open bite cases, there were considerable alterations in TMJ components, most likely as a result of functional demands.

Dynamic 3D images fusion of the temporomandibular joints: A novel technique

ObjectivesTo demonstrate a procedure for fusing images from cone-beam computed tomography (CBCT), magnetic resonance imaging (MRI) and optical positioning tracking system to dynamically evaluate the relative motion of the temporomandibular joint (TMJ) for the diagnosis of temporomandibular disorders (TMD). MethodsCBCT data was collected from a patient wearing a fixation device with markers in the intercuspal position. The patient's mandibular movements were recorded using an optical positioning tracking system. The CBCT data were imported into a virtual simulation system to reproduce the mandibular movement. Five jaw positions were selected for 3D printing of the occlusal plate that the patient wore to undergo MRI. MRI scans were registered with the CBCT image for fusion and reconstruction. ResultsThe anatomical structures of the articular fossa, articular disc, and condyle were clearly displayed in the CBCT-MRI fused images. The spatial posture and relative position of the fossa-disc-condyle during mandibular movement could be reproduced dynamically using the 3D reconstruction model. ConclusionsThis method can visually display mandibular motion trajectories and the relative TMJ positions. Virtual reproduction provides a comprehensive understanding of the articular disc's morphology and position in different states from a 3D perspective. Clinical SignificanceThis method can be used in clinical studies of TMJ as an adjunct to the 3D dynamic diagnosis and assessment for complex patients with TMD and provide relevant data for doctors.

Comparison of the Post-Surgical Position of the Temporomandibular Joint after Orthognathic Surgery in Skeletal Class III Patients and Patients with Cleft Lip and Palate.

Objective: The purpose of our research is to compare the post-surgical position of the temporomandibular joint in skeletal Class III patients and patients with cleft lip and palate treated with two-jaw orthognathic surgery using a three-dimensional computer tomography image. Materials and Methods: Twenty-three skeletal Class III patients with mandibular prognathism associated with maxillary retrognathism in group 1 and twenty cleft mid-face retrusion skeletal Class III patients in group 2 were enrolled in this study. All subjects were treated with two-jaw orthognathic surgery. Computed tomography scans were taken in all subjects at 3 weeks preoperatively and 6 months postoperatively. Three-dimensional craniofacial skeletal structures were build-up, and assessed the temporomandibular joint position changes before and after surgery. Results: Forty-three selected patients were separated into two groups. The mean age of patients was 22.39 ± 4.8 years in group 1 and 20.25 ± 3.8 years in group 2. The range of mean three-dimensional discrepancy of the selected condylar points was 0.95–1.23 mm in group 1 and 2.37–2.86 mm in group 2. The mean alteration of intercondylar angle was 2.33 ± 1.34° in group 1 and 6.30 ± 2.22° in group 2. The significant differences in the discrepancy of TMJ and changes in intercondylar angle were confirmed within the intra-group and between the two groups. Conclusions: Significant changes in postoperative TMJ position were present in both groups. Furthermore, the cleft group presented significantly more postoperative discrepancy of TMJ and more changes in intercondylar angle after surgery. This finding may be a reason leading to greater postoperative instability in cleft patients compared with skeletal Class III non-cleft patients. Clinical Trial Registration Number: IRB No: 202201108B0.

Comprehensive three-dimensional positional and morphological assessment of the temporomandibular joint in skeletal Class II patients with mandibular retrognathism in different vertical skeletal patterns

BackgroundOnly a few studies have used 3D cone-beam computed tomography (CBCT) analysis to evaluate the positional and morphological characteristics of the temporomandibular joint (TMJ) in adults with skeletal Class II. No studies have focused on the case of skeletal Class II with mandibular retrognathism in different vertical skeletal patterns. As a result, this study aimed to evaluate and compare the position and morphology of TMJ in adults with skeletal Class II with mandibular retrognathism in different vertical skeletal patterns to the position and morphology of TMJ in the normal Chinese adult population in three dimensions.MethodsThis retrospective study analyzed CBCT images of 80 adult patients. Subjects with skeletal Class II with a normal sagittal position of the maxilla and mandibular retrognathism were classified according to the mandibular angle and facial height ratio into three groups of 20 subjects each: hypodivergent, normodivergent, and hyperdivergent groups, as well as a control group of 20 subjects. The following 3D measurements of TMJ were evaluated: (1) position, parameters, and inclination of the mandibular fossa; (2) position, parameters, and inclination of the mandibular condyle; (3) condyle centralization in their respective mandibular fossae; (4) anterior, posterior, superior, and medial joint spaces; and (5) 3D volumetric measurements of the TMJ spaces. Measurements were statistically analyzed by one-way ANOVA test, followed by Tukey’s post hoc test.ResultsSignificant differences were found in the hyperdivergent and hypodivergent groups compared with the normal group in the vertical and anteroposterior mandibular fossa position, vertical condylar inclination, and condylar width and length. The hyperdivergent group showed the significantly highest condylar inclination with the midsagittal plane; anterior and superior positioning of the condyle; smallest anterior, superior, and medial joint spaces; and largest volumetric total joint space relative to the two other groups.ConclusionsThe condyle-fossa position and morphology differ with various vertical facial patterns in individuals with skeletal Class II mandibular retrognathism. These differences could be considered during TMD diagnosis and orthodontic treatment.

Cone-beam CT evaluation of temporomandibular joint in skeletal class II female adolescents with different vertical patterns

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 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 (H2&4=10.517, P=0.002), biggest superior (LSD-t2&3=3.408, LSD-t2&4=5.369, P < 0.001) and lateral (LSD-t2&3=2.767, LSD-t2&4=3.350, P=0.001) joint spaces, whereas group 4 showed the shortest condylar long axis diameter (H2&4=13.374, P < 0.001), largest glenoid fossa vertical distance (LSD-t2&4=4.561, P < 0.001, LSD-t3&4=2.713, P=0.007), smallest medial (LSD-t2&4=-4.083, P < 0.001) and middle (LSD-t2&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.

Changes in the temporomandibular joint position depending on the sagittal osteotomy technique and extent of mandibular movement

The bilateral sagittal split osteotomy (BSSO) and high oblique sagittal split osteotomy (HSSO) are common techniques for mandibular movement in orthognathic surgery. The aim of this study was to evaluate the influence of both techniques, as well as movement distances and directions, on the position of the temporomandibular joint (TMJ). A total of 80 mandibular movements were performed on 20 fresh human cadaver heads, four on each head. Pre- and postoperative cone beam computed tomography was used to plan the surgical procedure and analyse the TMJ. Reference measurements included the anterior, superior, and posterior joint spaces, intercondylar distances and angles in the axial and coronal planes, and the sagittal, coronal, and axial angulations of the proximal segment. Only minor differences were found between the BSSO and HSSO techniques, particularly in terms of the intercondylar angle in the axial plane (P < 0.03) and the condylar angle of the proximal segment in the sagittal plane (P < 0.011). Observed changes in the TMJ were mostly opposite when moving the mandible forwards and backwards and increased with increasing movement distance. BSSO and HSSO result in similar changes in TMJ position. The extent of the movement distance influences the position of the condyle more than the osteotomy technique.

Temporomandibular Joints’ Morphology and Osteoarthritic Changes in Cone-Beam Computed Tomography Images in Patients with and without Reciprocal Clicking—A Case Control Study

Background: Patients referred for orthodontic treatment often present symptoms of temporomandibular joints’ disorders (TMD), predominantly clicking. The objective was to analyze the morphology of the temporomandibular joints in cone-beam computed tomography (CBCT) images based on the presence of reciprocal clicking before orthodontic treatment. Methods: 105 participants took part in the study. 210 temporomandibular joints (TMJs) were allocated into one of two groups regarding the presence of reciprocal clicking. Morphology of condyle’s head, glenoid fossa, and articular eminence as well as condylar head position in the glenoid fossa and osteoarthritic changes in the area of the condylar head were examined for each TMJ in the CBCT images. Statistical analysis was performed with STATISTICA version 12.0. The following tests were performed: U-Mann Whitney, Kruskal-Wallis, t-Student, and chi-square. The statistical significance level was p = 0.05 for all the measurements included. Results: Significantly smaller condylar A-P dimension (p = 0.040) characterized temporomandibular joints with reciprocal clicking. Condyles were substantially more often positioned posteriorly (p = 0.043) and were significantly more often accompanied by subcortical cysts and pathologic osteoarthritic bone changes (p < 0.001). Conclusions: The early stages of internal derangements stay with alterations in morphology and position of TMJs as well as with the presence of osteoarthritic changes.

Comparative cone-beam computed tomography evaluation of temporomandibular joint position and morphology in female patients with skeletal class II malocclusion.

ObjectiveThis study was performed to evaluate the position and morphology of the temporomandibular joint in female patients with skeletal class II malocclusion and to investigate the association between temporomandibular joint disorders and facial types using cone-beam computed tomography.MethodsA lateral cephalogram was taken to determine the skeletal class of each participant. Sixty female patients aged 16 to 28 years were divided into high-angle, low-angle, and control groups. The shape of the condyle–fossa was measured and assessed on cone-beam computed tomography images of the 120 temporomandibular joints.ResultsSome condylar shape measurements displayed statistically significant differences among the groups. No significant differences were found in the length of the condyle, width of the glenoid fossa, or height of the articular eminence among the three groups. The posterior condylar position was more frequently observed in the low-angle group, whereas the anterior condylar position was more prevalent in the high-angle group.ConclusionThe present study revealed differences in the condyle–fossa morphology and position in female patients with skeletal class II malocclusion with different vertical facial types.

Changes of temporomandibular joint position after surgery first orthognathic treatment concept

Orthognathic surgery treatment (OGS) after orthodontic treatment of dentofacial deformities is a widely performed procedure, often accompanied by a bilateral sagittal split osteotomy (BSSO). Positioning of the condyle during this procedure is a crucial step for achieving optimal functional and anatomical results. Intraoperatively poorly positioned condyles can have a negative effect on the postoperative result and the patient’s well-being. Changes of the condylar position during OGS Procedures and its effects on the temporomandibular joint in orthognathic surgical interventions (OGS) are subject of scientific discussions. However, up to date, no study has investigated the role of condyle position in the surgery first treatment concept. The aim of this study was to investigate the influence of OGS on the three-dimensional position of the condyle in the joint in a surgery first treatment concept without positioning device and to record the change in position quantitatively and qualitatively. Analysis of our data indicated that OGS in surgery first treatment concept has no significant effect on the position of the condyle and the anatomy of the temporomandibular joint.

Usefulness of Early Plate Removal in Patients With Occlusal Discrepancies After Sagittal Split Ramus Osteotomy.

The aim of this study was to evaluate the effects of early removal of fixed plates in patients with occlusal discrepancies after sagittal split ramus osteotomy (SSRO) with a focus on the positional relationship of the temporomandibular joint (TMJ). Sagittal split ramus osteotomy with/without Le Fort I osteotomy was performed on 98 patients with mandibular prognathism. Of these 98 patients, 15 with occlusal discrepancies and/or TMJ symptoms underwent early plate removal after SSRO. Finally, 12 consecutive patients were evaluated in this study: 7 underwent bilateral SSRO, 1 underwent unilateral SSRO, and 4 underwent bilateral SSRO with maxillary advancement. The axiolateral TMJ Schuller method was used to evaluate the TMJ position. The authors measured 3 spaces (anterior, superior, and posterior joint spaces) between the condyle and glenoid fossa in the sagittal plane. The anterior and superior joint spaces were significantly larger immediately after the operation than before the operation. After early plate removal, these spaces significantly decreased in size. The posterior joint space increased, but with no significant difference. Three months after SSRO, the size of each of the 3 spaces was closely related to its preoperative size. In conclusion, these results suggest that early removal of fixed plates is 1 treatment option for postoperative occlusal discrepancies after SSRO.

Computer assisted positioning of the proximal segment after sagittal split osteotomy of the mandible: Preclinical investigation of a novel electromagnetic navigation system

IntroductionModifications of the temporomandibular joint position after mandible osteotomy are reluctantly accepted in orthognathic surgery. To tackle this problem, we developed a new navigation system using miniaturized electromagnetic sensors. Our imageless navigation approach is therefore optimized to avoid complications of previously proposed optical approaches such as the interference with established surgical procedures and the line of sight problem. Material and methodsHigh oblique sagittal split osteotomies were performed on 6 plastic skull mandibles in a laboratory under conditions comparable to the operating theatre. The subsequent condyle reposition was guided by an intuitive user interface and performed by electromagnetic navigation. To prove the suitability and accuracy of this novel approach for condyle navigation, the positions of 3 titanium marker screws placed on each of the proximal segments were compared using pre- and postoperative Cone Beam Computed Tomography (CBCT) imaging. ResultsGuided by the electromagnetic navigation system, positioning of the condyles was highly accurate in all dimensions. Translational discrepancies up to 0,65 mm and rotations up to 0,38° in mean could be measured postoperatively. There were no statistically significant differences between navigation results and CBCT measurements. ConclusionThe intuitive user interface provides a simple way to precisely restore the initial position and orientation of the proximal mandibular segments. Our electromagnetic navigation system therefore yields a promising approach for orthognathic surgery applications.

Computed tomography assessment of temporomandibular joint position and dimensions in patients with class II division 1 and division 2 malocclusions.

BackgroundThis study aimed to investigate and compare the positions and dimensions of the temporomandibular joint and its components, respectively, in patients with Class II division 1 and division 2 malocclusions.Material and MethodsComputed tomography images of 14 patients with Class II division 1 and 14 patients with Class II division 2 malocclusion were included with a mean age of 11.4 ± 1.2 years. The following temporomandibular joint measurements were made with OsiriX medical imaging software program. From the sagittal images, the anterior, superior, and posterior joint spaces and the mandibular fossa depths were measured. From the axial images, the greatest anteroposterior and mediolateral diameters of the mandibular condyles, angles between the long axis of the mandibular condyle and midsagittal plane, and vertical distances from the geometric centers of the condyles to midsagittal plane were measured. The independent samples t-test was used for comparing the measurements between the two sides and between the Class II division 1 and 2 groups.ResultsNo statistically significant differences were observed between the right and left temporomandibular joints; therefore, the data were pooled. There were statistically significant differences between the Class II division 1 and 2 groups with regard to mandibular fossa depth and anterior joint space measurements.ConclusionsIn Class II patients, the right and left temporomandibular joints were symmetrical. In the Class II division 1 group, the anterior joint space was wider than that in Class II division 2 group, and the mandibular fossa was deeper and wider in the Class II division 1 group. Key words:Temporomandibular joint, Class II malocclusion, Cone beam computed tomography.