Changes In Condylar Position Research Articles

The preliminary study of the effects of individual musculoskeletally stable position in the treatment of temporomandibular disorders

BackgroundTemporomandibular Disorders (TMD) is the dysfunction of group of muscles and bones in the joint area, the main symptoms of TMD are the pain of the chewing muscles and (or) the temporomandibular joints, mandibular movement disorders and joint noise. This study was designed to explore the therapeutic effects following Individual Musculoskeletally Stable (IMS) position stabilization splint therapy for TMD patients using Fricton index, cone beam computed tomography (CBCT) and surface-Electromyogram (sEMG).MethodsIn this study, we enrolled 31 TMD patients (ranging from 18 to 26 years old, including 7 males and 24 females), first Fricton index was used to evaluate the clinical curative effect of TMD with the treatment of IMS stabilization splint; then CBCT was used to observe the TMJ condylar position changes of TMD before and after the treatment of IMS stabilization splint; finally sEMG was used to observe the changes of electromyography of anterior temporalis (AT) and masseter muscles (MM) of TMD before and after the treatment of IMS stabilization splint.ResultsThe course of treatment was 6–8 months, with an average of 7.6 months. After the IMS stabilization splint treatment, TMD symptoms relieved, especially in pain, mandibular movement disorder, but still slightly inferior in the treatment of joint noise. And there was a statistically significant difference in the anterior and inner joint space, the condyle had the tendency of moving forward and outward. AT presented reduction significantly of EMG value at rest position after treatment.ConclusionsIMS stabilization splint is a therapeutic reversible treatment for TMD, especially for pain and mandibular movement disorder; it produces effects of forward and outward condylar movement and elimination of the masticatory muscles antagonism.

Effect of transcutaneous electrical nerve stimulation therapy on condylar position and myofascial pain in patients with temporomandibular joint disorders-A pilot clinical trial.

Temporomandibular joint disorders (TMD) are a type of disorder that affects the temporomandibular joint, muscles, and nerves leading to persistent facial pain. Transcutaneous electrical nerve stimulation (TENS) therapy is an alternative treatment for pain relief in TMD patients. The aim of the study was to assess the condylar position changes and pain levels occurring in TMD patients after TENS therapy. According to the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) criteria, a total of seven patients with TMD were included in this study. Routine diagnostic investigations were taken for each patient along with joint vibration analysis (JVA), electromyography (EMG), and a cone beam computed tomography (CBCT) at rest position. Using the Dolphin software (version 11.95), the temporomandibular joint spaces were measured on the CBCT for the right and left sides individually for each patient. These patients were then subjected to TENS therapy, and an EMG reading was taken post-TENS therapy to evaluate the effect on muscle strain. A CBCT was taken after the TENS therapy to assess its effect on the condylar position. The statistical significance of the pre- and post-temporomandibular joint spaces and the EMG readings post-TENS therapy were assessed using paired t-tests, respectively. There was a change in the anterior, middle, and posterior dimensions observed radiographically, before and after TENS. However, the results were found to be statistically significant only in the anterior region on the right joint space (P = 0.03) and posterior region of the left joint space (P = 0.04). TENS therapy has been found to bring about a change in the condylar position and pain intensities by relieving inadvertent muscle activity in the temporomandibular region. Therefore, further studies with larger sample sizes and control are required to fully ascertain the role of inadvertent muscle activity on the TMJ.

Mandibular advancement device in obstructive sleep apnea treatment: what happens to the condyle position and patient response?

This study aims primarily to assess the mandibular condyles and patient response to MAD therapy using cone-beam computed tomography (CBCT). Also, the study proposes to analyze whether variations in condylar position, OSA severity and mandibular protrusion influence patient response. 23 patients diagnosed with mild/moderate OSA and treated with MAD comprised the sample. Clinical, CBCT, and PSG assessments were conducted at baseline and with MAD in therapeutic protrusion (4-6 months of MAD use). The condyle position was vertically and horizontally evaluated at baseline and at the therapeutic protrusion. The condyle position significantly changed with MAD, showing anterior (7.3 ± 2.8mm; p < 0.001) and inferior (3.5 ± 1mm; p < 0.001) displacement. Patients with mild OSA required more protrusion (p = 0.02) for improvement. Responders exhibited a significantly prominent (p = 0.04) anterior baseline condyle position. A negative modest correlation was found between treatment response and baseline condyle anterior position (p = 0.03; r=-0.4), as well as between OSA severity and the percentage of maximum protrusion needed for therapeutic protrusion (p = 0.02; r=-0.4). The patient protrusion amount did not predict condylar positional changes. Neither condyle position, OSA severity, nor therapeutic protrusion were predictors of MAD treatment response. MAD resulted in anterior and inferior condylar displacement, and the amount of protrusion did not predict condylar positional changes. Responders showed a more anterior baseline condyle position. OSA severity and mandibular protrusion did not predict treatment response.

Pre- and Post-Operative Cone Beam Computed Tomography Assessment of the Temporomandibular Joint in Patients with Orthognathic Surgery.

This study aimed to compare the pre- and post-operative temporomandibular joint (TMJ) condylar position in dentofacial deformity (DFD) patients who had orthognathic surgeries using cone beam computed tomography (CBCT). A retrospective study evaluating the pre- and post-operative CBCT for 79 DFD patients (equivalent to 158 TMJs) (mean age = 26.62 ± 9.5 years) with a bilateral sagittal split osteotomy with or without Le Fort I surgeries (n = 29 Class II DFD, n = 50 Class III DFD) was performed. This included the compartmental measurement of TMJ spaces, in addition to the measurement of intercondylar distances and angles. Condylar position centricity was assessed using the Pullinger and Hollender formula. Clinical data were analysed for DFD class, the type of surgery and post-operative CBCT timing. Pre- and post-operative measurements were compared statistically using a paired t-test, Wilcoxon signed-rank test, and Stuart-Maxwell test. TMJ condyles tended to relocate post-operatively in a posterosuperior position with internal rotation in Class II DFD and a superior position with internal rotation in Class III DFD. However, the overall changes were within <0.5 mm translation and <4° rotation and the number of concentrically positioned condyles (according to the Pullinger and Hollender formula) did not change significantly. Orthognathic surgery is associated with minor post-operative translational and rotational condylar positional changes in Class II and III DFDs.

Improvement of the temporomandibular joint symptoms due to the condylar position change following modified L-shaped intraoral vertico-sagittal ramus osteotomy: a single-center, retrospective study.

Intraoral vertico-sagittal ramus osteotomy (IVSRO) was first reported by Choung in 1992 as a surgical procedure to decrease postoperative condylar dislocation. In 2017, Iwanaga et al. developed modified L-shaped IVSRO (mIVSRO) to reduce postoperative nerve dysfunction and achieved favorable outcomes. This study aimed to clarify the effect of mIVSRO on changes in temporomandibular joint (TMJ) symptoms and three-dimensional condylar position. We conducted a retrospective study of thirty sides in fifteen Japanese adults diagnosed with jaw deformities who underwent mIVSRO and sagittal split ramus osteotomy (SSRO). TMJ symptoms were assessed chronologically, and the condylar long axis and the condylar position were analyzed two- and three-dimensionally using axial cephalograms and cone-beam computed tomography. Postoperative TMJ symptoms improved by 90% (9/10 sides) in the mIVSRO group and by 50% (7/14 sides) in the SSRO group. The mIVSRO group exhibited outward rotation of the condylar long axis, while the SSRO group exhibited inward rotation. Moreover, mIVSRO induced residual anteromedial-inferior deviation of the condyle. The inclination angle of the condylar process was not significantly different between the two procedures pre- and postoperatively. These results clearly demonstrated the effect of mIVSRO on symptomatic TMJ. Residual changes in the position of the condyle following mIVSRO may not affect jaw function.

Three-Dimensional Changes of Condylar Position After Bimaxillary Surgery to Correct Skeletal III Malocclusion: Cone Beam Computed Tomography Voxel-Based Superimposition Analysis

BackgroundThe stability of the condylar position within the first three months after orthognathic surgery in patients with skeletal Class III malocclusion is crucial for subsequent orthodontic treatment. PurposeThe purpose was to compare condylar positional changes three months after bimaxillary surgery to correct skeletal Class III deformities, utilizing the conventional two-dimensional (2D) combined with the cone beam computed tomography (CBCT) voxel-based superimposition analysis. Study design, setting, sampleThis retrospective cohort study included skeletal Class III patients undergoing bimaxillary orthognathic surgery at Khon Kaen University, Thailand in 2020. Exclusion criteria were patients with temporomandibular disorder (TMD) symptoms, facial asymmetry prior to the surgery, or surgical complications. Exposure variableThe exposure variable was the timing, both preoperatively and 3 months postoperatively. This 3-month postoperative time point was chosen because complete healing of the bimaxillary surgery is expected by then, without any potential influence of condylar changes resulting from subsequent orthodontic treatment. Main outcome variablesThe outcome variable is condylar position measurement, joint space (mm) and axial condylar angle (degrees). CovariatesDemographics (age, sex), and surgical details (direction and amount of movement) were collected as covariates. AnalysesStatistical analysis of condylar positional changes and correlations was performed using paired t-test and linear correlation (P-value < 0.05), respectively. ResultsThe sample included 11 subjects (22 condyles), with a mean age of 24±5.24 years. Both 2D measurements and voxel-based 3D superimposition showed significant changes in condylar position three months after bimaxillary surgery: inferior (0.45±0.26 mm, P < 0.001), posterior (0.46±0.39 mm, P = 0.003), lateral (0.38±0.42 mm, P = 0.01) displacement, and inward rotation (5.21±2.54°, P < 0.001). No significant correlation was found between jaw movement distance and condylar changes. Conclusions and relevanceTo our knowledge, this is the first study to report measures of condylar changes at 3 months, when complete healing of the osteotomies would be expected, using Le Fort I osteotomy for maxillary advancement combined with bilateral sagittal split ramus osteotomy (BSSRO) for mandibular setback. These changes are small in magnitude and may be of little relevance to patient care.

Three-Dimensional Evaluation of Changes in Condylar Position After Orthognathic Surgery With Different Types of Jaw Deformities

BackgroundAssessing condyle position post orthognathic surgery is pivotal for optimizing surgical accuracy, sustaining postoperative stability, and ensuring predictable treatment outcomes. PurposeThe aim of this study was to analyze the changes of condyle position after orthognathic surgery with different types of jaw deformity and to analyze whether the changes of condyle position are different. Study design, setting, sampleA retrospective cohort study was designed and conducted, involving adults who underwent orthognathic surgery for jaw deformities at the affiliated Stomatological Hospital of Nanchang University between 2019 and 2022. Patients with incomplete CT data were excluded. Predictor/exposure/independent variableThe primary predictor variable was time (pre-operative and post-operative) and types of jaw deformities (skeletal Class III, skeletal Class II, and mandibular deviation). Main outcome variable(s)The main outcome variables were the 3D linear and rotational positional changes of the condyle. CovariatesEvaluated covariates included sex and age. AnalysesMIMICS 20.0 software measured all data, and SPSS 22.0 software facilitated statistical analyses. Intra- and inter-group correlation analyses employed paired t-tests and independent t-tests, with statistical significance set at P < 0.05. ResultsThe study sample was composed of 32 subjects with a mean age of 22.43±1.6 and 9 were male. The analysis of changes of condylar position from virtual surgical planning to immediate postoperative period showed that the maximum condylar displacement was 1.74 mm and the maximum angular change was 3.92°. The analysis of changes in condylar position from the immediate postoperative period to 1-year postoperatively showed no statistically significant changes for the same type of jaw deformity. But patients with Class II malocclusion exhibited distinct condylar displacement and rotation patterns compared to those with Class III malocclusion and mandibular deformity. Conclusions and RelevanceThe application of virtual surgical planning in orthognathic surgery ensures a high degree of consistency in achieving the desired condylar position. Moreover, no significant change in condylar position was observed after orthognathic surgery for the same type of jaw deformity. However, patients with Class II deformities exhibited a higher susceptibility to rotational displacement of the condyles compared to those with other types of jaw deformities.

An automated method for assessing condyle head changes in patients with skeletal class II malocclusion based on CBCT images.

Currently, there is no reliable automated measurement method to study the changes in the condylar process after orthognathic surgery. Therefore, this study proposes an automated method to measure condylar changes in patients with skeletal class II malocclusion following surgical-orthodontic treatment. Cone-beam computed tomography (CBCT) scans from 48 patients were segmented using the nnU-Net network for automated maxillary and mandibular delineation. Regions unaffected by orthognathic surgery were selectively cropped. Automated registration yielded condylar displacement and volume calculations, each repeated three times for precision. Logistic regression and Linear regression were used to analyze the correlation between condylar position changes at different time points. The Dice score for the automated segmentation of the condyle was 0.971. The Intraclass correlation coefficients (ICCs) for all repeated measurements ranged from 0.93 to 1.00. The results of the automated measurement showed that 83.33% of patients exhibited condylar resorption occurring six months or more after surgery. Logistic regression and Linear regression indicated a positive correlation between counterclockwise rotation in the Pitch plane and condylar resorption(p < 0.01). And a positive correlation between the rotational angles in both three planes and changes in the condylar volume at six months after surgery(p ≤ 0.04). This study's automated method for measuring condylar changes shows excellent repeatability. Skeletal class II malocclusion patients may experience condylar resorption after bimaxillary orthognathic surgery, and this is correlated with counterclockwise rotation in the sagittal plane. This study proposes an innovative multi-step registration method based on CBCT, and establishes an automated approach for quantitatively measuring condyle changes post-orthognathic surgery. This method opens up new possibilities for studying condylar morphology.

Comparison of condylar position after free fibular flap mandibular reconstruction using computer-assisted and traditional techniques

ObjectivesTo compare the changes in condylar position after mandibular reconstruction with free fibular flap(FFF) and the differences between computer-assisted techniques and traditional methods on CT images.MethodsThirty-four patients who underwent mandibular reconstruction with free fibular flap were selected according to the inclusion and exclusion criteria. In the 3D group, virtual surgical planning (VSP) with osteotomy cutting plate and placement guiding plate were used, while the traditional group underwent freehand reconstruction. The CT data of 68 temporomandibular joints (TMJs) were recorded before and immediately after surgery. The condylar position was evaluated by measuring the anterior space (AS), posterior space (PS) and superior space (SS), and the ln (PS/AS) was calculated according to the method proposed by Pullinger and Hollender.ResultsIn the patients included in the 3D group, the condyle on the ipsilateral side moved slightly backward; however, in the patients in the traditional group, the ipsilateral side moved considerably anteroinferior. No obvious changes on the contralateral side were noted. In the 3D group, 33% of ipsilateral condyles were in the posterior position postoperatively when compared with the preoperative position (13%). In the traditional group, the number of ipsilateral condyles in the anterior position increased from 4 to 10, accounting for 53% postoperatively. Contrary to the traditional group, the 3D group presented less condylar displacement on the ipsilateral side postoperatively.ConclusionsThis study showed a decreased percentage of change in condylar position postoperatively when VSP was used. Virtual surgical planning improved the accuracy of FFF mandibular reconstruction and made the condylar position more stable.

Does adjunctive fixation in conjunction with miniplate affect condylar position and morphology after mandibular advancement through bilateral sagittal split ramus osteotomy? A retrospective 3-dimensional CT comparative study

To minimize condylar positional and morphological changes after mandibular advancement through bilateral sagittal split ramus osteotomy (BSSRO), surgeons add either a bicortical screw or a two-hole plate distal to the conventional single miniplate. Since there have been no previous studies investigating the effect of this combination, our study aimed to evaluate the short- and long-term effects of these adjunctive fixation methods (AFM) on condylar positional and morphological changes after mandibular advancement through BSSRO.This retrospective cohort study included consecutive patients with retruded mandibles who were treated in the Department of Orthognathic and TMJ Surgery at West China Hospital of Stomatology, Sichuan University. The patients were divided into two groups based on the primary predictor variable, which was the addition of AFM — either a single bicortical screw or a two-hole plate in addition to the single miniplate. The primary outcome variable was the condylar positional and morphological changes after mandibular advancement through BSSRO. Three-dimensional facial CT scans were obtained at three different time points (preoperatively — T0, 1 week postoperatively — T1, and 1 year postoperatively — T2) and analyzed using ITK-SNAP, 3D Slicer, and SlicerSALT software. Intergroup comparisons were conducted with an independent t-test, with a p-value of <0.05 considered significant. Correlations between the variables were estimated by Pearson correlation. The study comprised 51 patients (32 females, 19 males; mean age 25.13 ± 4.24 years), involving a total of 81 condyles (21 unilateral and 60 bilateral).There was a significant difference in long-term condylar displacement in favor of AFM along with a single miniplate (p < 0.001). The bicortical screw group recorded less condylar displacement than the two-hole plate group horizontally (0.11 mm vs 0.22 mm) and sagittally (0.03 mm vs 0.17 mm), but more vertically (0.85 mm vs 0.03 mm). Bone formation associated with AFM occurred on all condylar surfaces, compared with only three surfaces in the single miniplate group.The adjunctive method in addition to the single miniplate fixation method showed less condylar displacement and more bone apposition after mandibular advancement through BSSRO. The follow-up duration variable was the only significant determinant for volumetric changes in the condyle.

Effectiveness of Occlusal Splint Therapy in Moderating Temporomandibular Joint Disorders With Joint Displacement: A Retrospective Analysis Using Cone Beam Computed Tomography.

Background Temporomandibular joint disorders (TMD) represent a prevalent group of conditions impacting the temporomandibular joint. Among the therapeutic interventions, occlusal splint therapy has gained recognition for its potential to address TMD symptoms, particularly in cases involving joint displacement. Objective This study aims to investigate the effectiveness of occlusal splint therapy in cases of moderate TMD with joint displacement, focusing on changes in condylar position, joint morphology, and patient-reported outcomes. Methods A retrospective analysis was conducted involving 148 participants who underwent occlusal splint therapy between January 2018 and December 2020. Data were collected through cone beam computed tomography (CBCT) imaging for precise assessments of condylar position and joint morphology. Ethical approval was obtained, and participants provided informed consent. Baseline characteristics, medical history, and TMD severity were recorded. Occlusal splint therapy included individualized fabrication, occlusal analysis, adjustments for optimal fit, and prescribed wear schedules. Follow-up included CBCT scans at specified intervals (three months and six months), with participant-reported outcomes collected. The data analysis was conducted using IBM SPSS Statistics for Windows, Version 22.0 (Released 2013; IBM Corp., Armonk, NY, USA). Paired t-tests or nonparametric equivalents were employed to assess changes in condylar position and joint morphology. Subgroup analyses were conducted to explore potential factors influencing treatment outcomes. The significance level was set at p < 0.05 for all statistical tests. Results The entire cohort (n = 148) had a mean age of 32.5 years (± 8.1), with a balanced gender distribution. Changes in condylar position revealed a statistically significant improvement (p = 0.03), with a mean decrease of 0.2 mm posttreatment. Joint morphology changes indicated increased joint space width (p = 0.01), improved disc position (p = 0.02), and nonsignificant alterations in bony structures (p = 0.10). Patient-reported outcomes demonstrated significant improvements in pain levels, jaw functionality, and satisfaction (all p < 0.001). Age and gender subgroup analyses showed consistent improvements in condylar position, joint morphology, and patient-reported outcomes across different groups. Conclusion Occlusal splint therapy demonstrated effectiveness in improving condylar position, joint morphology, and patient-reported outcomes in cases of moderate TMD with joint displacement. The findings underscore the potential of occlusal splint therapy as a viable intervention for managing TMD, providing valuable insights for clinicians and researchers.

Evaluation of condylar and mandibular movements on the upper airway during the use of mandibular advancement device for obstructive sleep apnea treatment.

To evaluate the temporomandibular joint (TMJ), condylar and mandibular movements in obstructive sleep apnea (OSA) patients treated with mandibular advancement device (MAD) and to identify the influence of these anatomic factors on upper airway (UA) volume and polysomnographic outcomes after treatment. Twenty OSA patients were prospectively treated with MAD. Clinical examinations, cone-beam computed tomography, and polysomnography were performed before MAD treatment and after achieving therapeutic protrusion. Polysomnographic variables and three-dimensional measurements of the TMJ, mandible, and upper airway were statistically analyzed. Condylar rotation, anterior translation, and anterior mandibular displacement were directly correlated with total UA volume, while vertical mandibular translation was inversely correlated with the volume of the inferior oropharynx. MAD treatment resulted in an increase in the volume and area of the superior oropharynx. There was no statistically significant correlation between condylar rotation and translation and polysomnographic variables. With MAD, there was a significant increase in vertical dimension, changes in condylar position (rotation and translation), and mandibular displacement. The central and medial lengths of the articular eminence were inversely correlated with condylar rotation and translation, respectively. The lateral length of the eminence was directly correlated with condylar translation, and the lateral height was directly correlated with condylar rotation and translation. Condylar and mandibular movements influenced UA volume. The articular eminence played a role in the amount of condylar rotation and translation. Individualized anatomical evaluation of the TMJ proves to be important in the therapy of OSA with MAD.

Direction and Range of Condylar Positional Changes in the First-Year Post-surgical Orthodontics Interventions in Adult Patients with Skeletal Class III Deformity: A Systematic Review and Meta-analysis.

Assess the available scientific literature regarding the direction and extent of condylar positional changes during the first year of post-surgical orthodontics interventions in class III patients. PubMed, Cochrane Library, Embase, and Google Scholar databases were searched up to March 2022 for studies involving the measurement of condylar positional changes after surgical treatment of Class III dentofacial deformity in adults with BSSO without or without Le Fort I osteotomies. The methodological index for non-randomized studies (MINORS) was utilized to assess the risk of bias and quality of non-randomized studies. Reporting of this review was based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Primary outcome was condyle positional changes between the following time points: T0: before treatment, T1: immediately post treatment, T2: 4, 6, or 9 months post treatment, T3: one year post treatment. Nineteen studies were included in the systematic review. Eleven studies were deemed low quality, and the rest were of medium quality. The meta-analysis included 12 studies and showed statistically significant downward, outward positional changes at T1(Immediately after surgery). Inward Yaw rotation was significant at T1(1-4month post-surgery) and T2(4-9months post-surgery). Surgically induced condylar changes tend to go back to normal within the first year after surgery, except for condylar yaw rotations.

Correlation between condylar, glenoid fossa and joint space changes two years after bimaxillary orthognathic surgery in class II subjects

The position of the mandible after an orthognathic surgical procedure is believed to be dependent on adaptive condylar and glenoid fossa changes, in addition to condylar positional changes within the fossa. The purpose of this study was to evaluate the association between condylar and glenoid fossa changes and the positional changes in the joint space two years after bimaxillary surgery. The condyles and glenoid fossae were reconstructed from a pair of superimposed pre- and postoperative (two years) cone-beam computerized tomography scans. The surface models were spatially divided into four regions. Three-dimensional morphological and positional changes were measured as volumetric differences and surface distances between the pre- and postoperative condylar and glenoid fossa regions. Statistical associations of condylar, glenoid fossa and joint space changes were calculated by Pearson's correlation coefficient. Twenty subjects (sixteen female; four male; mean age 27.6 years) with class II malocclusion and maxillomandibular retrognathia, who underwent bimaxillary surgery, were assessed. A strong and statistically significant correlation between condylar and glenoid fossa changes was observed two years after surgery (r = 0.52, p < 0.001). The correlation was strongest and statistically significant anterior-medially (r = 0.48, p = 0.002) and anterior-laterally (r = 0.38, p = 0.015). Condylar changes were significantly correlated with the increase in the posterior-medial (r = 0.37, p < 0.020) and the posterior-lateral (r = 0.45, p < 0.003) joint space distances. Changes of the condyle, the glenoid fossa and the joint space following bimaxillary surgery were significantly correlated in these class II subjects.

Condylar Positional Changes in Skeletal Class II and Class III Malocclusions after Bimaxillary Orthognathic Surgery.

Orthognathic surgery is indicated to modify the position of the maxillomandibular structure; changes in the mandibular position after osteotomy can be related to changes in the position of the mandibular condyle in the articular fossa. The aim of this study was to determine changes produced in the mandibular condyle 6 months after orthognathic surgery. A cross-sectional study was conducted that included subjects who had undergone bimaxillary orthognathic surgery to treat dentofacial deformity of Angle class II (group CII) or Angle class III (group CIII). Standardized images were taken using cone-beam computed tomography 21 days before surgery and 6 months after surgery; measurement scales were used to identify the condylar position and its relations with the anterior, superior, and posterior joint spaces. The results were analyzed using the Shapiro-Wilk and Student's t-tests, while considering a value of p < 0.05 as indicating a significant difference. Fifty-two joints from 26 patients, with an average age of 27.9 years (±10.81), were analyzed. All subjects in both group CII and group CIII showed a significant change in the anterior, superior, and posterior joint spaces. However, postoperative changes in the position of the condyle in the articular fossa were not significant in the anteroposterior analysis. We conclude that orthognathic surgery causes changes in the sagittal position of the mandibular condyle in subjects with mandibular retrognathism and prognathism.

Cephalometric Assessment of Condylar Position among Individuals with Different Skeletal Malocclusion Patterns

Introduction: There are variations in growth and orientation of cranial base region where the maxilla and mandible articulate. This leads to differential movement of the maxilla and mandible causing changes in glenoid fossa and condylar position. Therefore, this study was conducted to determine the condylar position in patients with different skeletal sagittal malocclusion patterns. Methods: An analytical cross-sectional study was conducted among 165 individuals, having skeletal Class I, Class II and Class III relationship (55 in each group) selected by convenience sampling method after receiving ethical approval and informed consent. Lateral cephalograms were taken and measurements for determining condylar position were done and compared among three groups. Data were analyzed in SPSS version 16. Kruskal-Wallis H test was used to determine the mean difference in between condylar positions of three skeletal malocclusion patterns and Mann-Whitney U test was done for their pairwise comparison. Results: There was no significant difference in posterior cranial base length (P=0.200) and saddle angle (P=0.517) in three skeletal malocclusion class groups. However, the three malocclusion patterns showed significant differences in gonian angle (P=0.001) and articular angle (P=0.013). Significant moderate negative correlation in saddle angle and articular angle (P&lt;0.001) was observed. Conclusion: The findings of this study concluded that condylar position based on posterior cranial base length was not associated with different skeletal malocclusion patterns. However, articular angle was significantly lower in skeletal class III than in class II.

Changes in condylar position and morphology after mandibular reconstruction by vascularized fibular free flap with condyle preservation.

Changes in condylar position and morphology after mandibular reconstruction are important to aesthetic and functional rehabilitation. We evaluated changes in condylar position and morphology at different stages after mandibular reconstruction using vascularized fibular free flap with condyle preservation. A total of 23 patients who underwent mandibular reconstruction with fibular flap were included in this retrospective study. CT data of all patients were recorded before surgery (T0), 7 to 14days after surgery (T1), and at least 6months after surgery (T2). Five parameters describing the condylar position and 4 parameters describing the morphology were measured in sagittal and coronal views of CT images. The association between clinical characteristics and changes in condylar position and morphology was analyzed. A finite element model was established to investigate the stress distribution and to predict the spatial movement tendency of the condyle after reconstruction surgery. The condylar position changed over time after mandibular reconstruction. The ipsilateral condyles moved inferiorly after surgery (T0 to T1) and continually move anteriorly, inferiorly, and laterally during long-term follow-up (T1 to T2). Contrary changes were noted in the contralateral condyles with no statistical significance. No morphological changes were detected. The relationship between clinical characteristics and changes in condylar position and morphology was not statistically significant. A consistent result was observed in the finite element analysis. Condylar positions showed obvious changes over time after mandibular reconstruction with condylar preservation. Nevertheless, further studies should be conducted to evaluate the clinical function outcomes and condylar position. These findings can form the basis for the evaluation of short-term and long-term changes in condylar position and morphology among patients who have previously undergone mandibular reconstruction by FFF with condyle preservation.

Remodeling of the Temporomandibular Joint After Mandibular Setback Surgery: A 3D Cephalometric Analysis

Condylar adaptations following orthognathic surgery remain an area of interest. Prior studies do not use 3-dimensional imaging modalities and lack standardization in the choice of osteotomy and movement when assessing condylar changes. The purpose of this study was to use 3-dimensional cephalometry to measure the association between osteotomy type (sagittal split osteotomy [SSO] vs vertical ramus osteotomy [VRO]) and changes in condylar volume and position. This is a retrospective cohort study from January 2021 through December 2022 of patients at Bellevue Hospital in New York City, New York who were treated with either SSO or VRO for the correction of Class III skeletal malocclusion. The primary predictor was the type of mandibular osteotomy, sagittal split osteotomy, and vertical ramus osteotomy. The primary outcomes were changes in condylar volume (change measured in mm3) and relative position (anterior-posterior change utilizing the Pullinger and Hollinder method). Covariates included patient age, sex, setback magnitude, temporomandibular joint symptoms, and fixation method for SSO patients. Univariate comparisons were performed between independent variables and study outcomes. Volume changes were compared within each predictor using paired t-tests. Position changes were compared within each predictor using χ2 tests. If there were multiple significant univariate predictors, multiple regression models were created to predict volume and position changes. A P<.05 value was considered statistically significant. The final sample comprised 30 condyles derived from 30 subjects. Mean age was 22.7years (SD=5.7) and mean setback was 3.9mm (SD=0.9). Twenty two condyles (73.3%) were subject to SSO with fixation, while the remaining 8 (26.7%) condyles were subject to intraoral VRO without fixation. When compared to VRO, condyles manipulated with SSO had greater volume loss (-177.2 vs -60.9mm3; P=.03) and positional change (68.2 vs 12.5%; P<.01). Self-reported measures of postoperative pain, internal derangement, and myofascial symptoms were not significantly associated with either volume or positional changes. The SSO resulted in greater postoperative condylar volume loss and positional changes. These volume and positional changes were not correlated with self-reported temporomandibular disorder symptoms.

Condylar positional changes and remodeling following bimaxillary anterior segment osteotomy with and without Le Fort I osteotomy: a three-dimensional comparative analysis.

To evaluate 3D condylar displacement and long-term remodeling following the correction of bimaxillary protrusion by anterior segment osteotomy (ASO) with and without Le Fort I surgery. This retrospective study included 32 adults with bimaxillary protrusion who underwent ASO alone (group 1) or with concomitant Le Fort I osteotomy (group 2). Subject's computed tomography scans at basic (T0), immediate postoperatively (T1), and at 1year or more follow-up (T2) were collected. The condyle displacement was measured at superior-inferior, lateromedially, and anteroposterior surfaces, while condyle remodeling was measured at the superior, lateral, anterior, medial, and posterior surfaces. All 3D analyses were performed using 3D Slicer software (4.11.2). At T1, 52.7%, 86.7%, and 94.4% of condyles in group 1 were displaced inferiorly, laterally, and posteriorly, respectively, as well as 75%, 89.2%, and 53.5% of condyles in group 2, which had not fully returned to the original preoperative positions at T2. Condylar remodeling was observed in both groups at T2, and no significant difference was found in the overall condylar volume between T1 and T2 in both groups. Patients in group 2 exhibited significant bone resorption at both lateral and anterior surfaces compared to group 1 (P = 0.000 and 0.01, respectively). This study's results demonstrated that ASO is associated with a degree of condylar changes even if the posterior mandible is not osteomized. The positional changes vary between bimaxillary ASO alone and those with simultaneous Le Fort I osteotomy. However, both groups' condyle volume remained stable at the long-term follow-up.

Changes in condylar position during orthodontic treatment depending on the amount of incisor retraction: a cone-beam computed tomography study.

Orthodontic treatment may be associated with temporomandibular disorders through changes in the condylar position. This study aimed to evaluate changes in the condylar position among different amounts of maxillary incisor retraction during orthodontic treatment using cone-beam computed tomography images. Fifty-four participants were enrolled and divided into minimal (n = 14), moderate (n = 20), and maximal (n = 20) retraction groups based on the amount of incisor retraction (< 1, 1-6, and > 6mm, respectively). Changes in condylar position before (T0) and after (T1) orthodontic treatment were assessed for the superior, anterior, posterior, and medial joint spaces (SJS, AJS, PJS, and MJS, respectively). Changes in joint spaces were compared between T0 and T1 in each group using paired t-tests and among the three groups using analysis of variance. Anterior movement of the condyle was observed in the maximal retraction group with a 0.2mm decrease in ΔAJS and a 0.2mm increase in ΔPJS, significantly greater than those in the minimal retraction group. The AJS and PJS showed statistically significant differences between T0 and T1 (P < 0.05) in the maximal retraction group. The condyle may show a statistically significant but clinically insignificant forward movement in the maximal incisor retraction group, whereas it was relatively stable in the minimal and moderate incisor retraction groups. More attention should be paid to the signs and symptoms of the condyle in patients with excessive incisor retraction during orthodontic treatment.