BACKGROUND: Mandibular malpositioning may result in an abnormal concentration of stresses within the temporomandibular joint (TMJ) in adult rats, which may further lead to a series of pathological changes, such as articular cartilage wear, subchondral bone sclerosis and osteophyte formation. However, the pathological and adaptive changes in condylar cartilage caused by different stress distributions are still controversial.
OBJECTIVE: The aim of this study was to observe the effect of sagittal changes in mandibular position on condylar cartilage by changing the occlusal vertical dimension (OVD) in adult rats.
METHODS: Fifteen-week-old female rats were divided into three groups: control (CON), increased OVD (iOVD) and loss of occlusion (LO) groups. An occlusal plate and tooth extraction were used to establish the animal model. TMJ samples of the experimental and CON groups were observed and investigated by bone morphological, histomorphological and immunohistochemical staining analyses at 3 days, 1 week, 2 weeks, 4 weeks and 8 weeks. Weight curves were plotted.
RESULTS: Micro-computed tomography showed that, compared with the CON group, cartilage destruction followed by repair occurred in both experimental groups, which was similar to the trend observed in haematoxylin-eosin staining. All experimental results for the iOVD group showed an approximately similar time trend. Compared with the iOVD group, the toluidine blue and immunohistochemical staining results in the LO group showed no obvious change trend over time.
CONCLUSIONS: Compared with occlusal loss, an increase in OVD caused faster and more severe damage to condylar cartilage, and subchondral bone repair occurred later.

OBJECTIVE: 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.
METHODS: Cone-beam CT (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 analyse the correlation between condylar position changes at different time points.
RESULTS: 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 < .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 ≤ .04).
CONCLUSIONS: 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.
CONCLUSIONS: 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.

BACKGROUND: The aim of this study is to determine the best plate to use as a substitute to fix a medial femoral condyle fracture.
METHODS: The first part is to measure the best fit between several anatomical plates including the Proximal Tibia Anterolateral Plate (PT AL LCP), the Proximal Tibia Medial Plate (PT M LCP), the Distal Tibia Medial Locking Plate (DT M LCP) and the Proximal Humerus (PHILOS) plate against 28 freshly embalmed cadaveric distal femurs. Measurements such as plate offset and number of screws in the condyle and shaft shall be obtained. The subsequent part is to determine the compressive force at which the plate fails. After creating an iatrogenic medial condyle fracture, the cadavers will be fixed with the two plates with the best anatomical fit and subjected to a compression force using a hydraulic press.
RESULTS: The PT AL LCP offered the best anatomical fit whereas the PHILOS plate offered the maximal number of screws inserted. The force required to create 2 mm of fracture displacement between the two is not statistically significant (LCP 889 N, PHILOS 947 N, p = 0.39). The PT AL LCP can withstand a larger fracture displacement than the PHILOS (LCP 24.4 mm, PHILOS 17.4 mm, p = 0.004).
CONCLUSIONS: Both the PT AL LCP and the PHILOS remain good options in fixing a medial femoral condyle fracture. Between the two, we would recommend the PT AL LCP as the slightly superior option.

Temporomandibular joint (TMJ) osteoarthritis (OA) is a common TMJ degenerative disease with an unclear mechanism. Synovial fluid (SF), an important component of TMJ, contains various proteins and metabolites that may directly contribute to OA. The present study aimed to investigate the influence of SF in TMJOA at the metabolite level.
Untargeted and widely targeted metabolic profiling were employed to identify metabolic changes in SF of 90 patients with different TMJOA grades according to TMJ magnetic resonance imaging.
A total 1498 metabolites were detected. Most of the metabolites were amino acids and associated metabolites, benzene and substituted derivatives, and lipids. Among patients with mild, moderate and severe TMJOA, 164 gradually increasing and 176 gradually decreasing metabolites were identified, indicating that biosynthesis of cofactors, choline metabolism, mineral absorption and selenocompound metabolism are closely related to TMJOA grade. Combined metabolomics and clinical examination revealed 37 upregulated metabolites and 16 downregulated metabolites in patients with pain, of which 19 and 26 metabolites were positively and negatively correlated, respectively, with maximum interincisal opening. A model was constructed to diagnose TMJOA grade and nine biomarkers were identified. The identified metabolites are key to exploring the mechanism of TMJOA.
In the present study, a metabolic profile was constructed and assessed using a much larger number of human SF samples from patients with TMJOA, and a model was established to contribute to the diagnosis of TMJOA grade. The findings expand our knowledge of metabolites in human SF of TMJOA patients, and provide an important basis for further research on the pathogenesis and treatment of TMJOA.

BACKGROUND: Temporomandibular joint osteoarthritis (TMJOA) is characterized by articular cartilage degeneration and progressive synovitis. How to effectively inhibit TMJOA in the early stage has been a hot topic in the biomedical field. As a non-invasive physiotherapy, pulsed electromagnetic field (PEMF) treatment has shown great potential in the treatment of osteoarthritis (OA) in extremity joints.
OBJECTIVE: This study aims to investigate the biological effect of PEMF intervention on TMJ cartilage degeneration and synovium inflammation at the early stage of TMJOA.
METHODS: PEMF (2.0 mT, 15 Hz, 2 h/day) treatment was given to rats in which TMJOA was induced by applying the unilateral anterior crossbite (UAC). Histological and immunohistochemical staining, TUNEL assay, real-time PCR and western blotting assay were performed to detect the changes of the morphology and the expression of pro-inflammatory and degradative factors in condylar cartilage and synovium.
RESULTS: Obvious condylar cartilage degeneration, characterized by decreased cartilage thickness, degraded cartilage extracellular matrix, increased expression of pro-inflammatory and degradative factors (TNF-α, IL-1β, MMP-13, ADAMTS-5, IL-6, MMP-3, MMP-9 and COL-X) and increased chondrocytes death, was observed in UAC group, accompanied by synovium hyperplasia and up-regulation of pro-inflammatory and degradative factors in synovium. PEMF intervention reversed the decreased cartilage thickness at 3 weeks and degraded cartilage extracellular matrix at 6 weeks. Moreover, the up-regulation of pro-inflammatory, degradative and hypertrophyic factors and chondrocytes death in condylar cartilage induced by UAC were inhibited to some extent. In addition, the synovium hyperplasia and the up-regulation of pro-inflammatory and degradative factors in synovium were inhibited at 3 weeks and 6 weeks.
CONCLUSIONS: Appropriate PEMF stimulation can reverse the loss of cartilage extracellular matrix, the chondrocytes death, the increased expression of pro-inflammatory and degradative factors in cartilage, the decreased cartilage thickness and synovium inflammation induced by UAC at the early stage of TMJOA to some extent. PEMF stimulation may be a promising method in clinical TMJOA treatment.

The aim of this study was to investigate the characteristics of condylar resorption in craniofacial microsomia (CFM) patients following mandibular distraction osteogenesis (MDO). Patients with unilateral type-IIa and type-IIb CFM, who had completed MDO and mandibular distractor extraction (MDE), were recruited. The height and volume of the condyle were measured on three-dimension models created by the analysis of computed tomography (CT) data. Normality analysis was performed using the Shapiro-Wilk test. Data for the affected and unaffected sides were compared using the paired t-test or Wilcoxon signed-rank test. Data for both type-IIa and type-IIb CFM were compared using the independent-samples t-test or Mann-Whitney U test. The Pearson or Spearman correlation was used to determine the correlations of condylar resorption rate with related measurements. In total, 48 type-IIa and 48 type-IIb CFM patients were included. The condylar resorption rate in type-IIa CFM (0.35 ± 0.32) was significantly associated with the height of the condyle (r = 0.776, p < 0.001) and distraction distance (r = 0.447, p = 0.001), while the condylar resorption rate in type-IIb CFM (0.49 ± 0.46) was significantly associated with the height of the condyle (r = 0.924, p < 0.001). However, there was no significant difference in condylar resorption rate between type-IIa and type-IIb CFM (p = 0.075). In addition to occlusal changes, no other negative symptoms of the TMJ were observed with condylar resorption. Condylar resorption was evident in CFM patients following mandibular distraction osteogenesis, and the condylar resorption rate showed a relationship with distraction distance and condylar height.

In this study we aim to describe the three-dimensional analysis of condylar deformation of the temporomandibular joint (TMJ) and morphological changes of the craniofacial jaw in patients with idiopathic condylar resorption (ICR). We also compare those with a control group that is healthy and matched for age and gender. Cone-beam computed tomography (CBCT) and cephalometric radiograph (X-ray) were conducted and analysis of craniofacial measurement, condylar width, length, height, and condylar axial angle changes were done three-dimensionally using ProPlan CMF™ 3.0 software (Materialise). The craniofacial jaw measurements of the ICR patients were significantly different than the control group and the significant changes in the mandible can be seen in ICR patients according to the results of this study. The results of smaller condylar width and height in the ICR group reflect the smaller size of the condyle compared with an unaffected condyle. Also, both right and left sagittal condylar angles (p = 0.001 and p = 0.003), respectively, and axial condylar angles (p = 0.01 and p = 0.02), respectively, displayed significant differences between the two groups. In conclusion, the vertical development of the condyle decreased along with reduced measurements in the width and height of the condyle in ICR patients, and differences in the morphology of the craniofacial jaw and condylar angles were observed between study groups.

The purpose of this article is to discuss the effective management of mandibular fractures in pediatric patients during the growing phase of the mandible using splint fiber and ligature wire.
A retrospective study examined pediatric patients with mandibular fractures who were treated using the splint (Quartz) fiber and ligature wire technique at the Stomatology Hospital of Xi\'an Jiaotong University from August 2021 to January 2023. Data on gender, age, location or site of the fracture, and development of tooth stage were collected from the patient\'s medical records. Descriptive statistics were used to analyze the data and evaluate the effectiveness of the splint (Quartz) fiber technique for treating mandibular fractures in pediatric patients.
Out of 256 subjects, 6 pediatric patients with mandibular fractures were selected, resulting in an incidence rate of 2.34% with an equal sex ratio. Mental or symphysis fracture was the most common site for fracture in children, accounting for 100% of cases. Right mandibular angle fracture was observed in 16.7% of patients, while 50% of the group (3 individuals) suffered from left condylar fracture and 16.7% had a bilateral condylar fracture. Treatment with Quartz splint fiber and circumdental arch wiring using ligature wire was successful with no observed post-treatment complications or malocclusion. The splint fiber was worn for 30 days and the circumdental arch wiring was for the same. Healing of bone fracture yields good results after 12 weeks. Follow-up care is crucial to monitor for complications, in this study, no post-treatment complications were observed.
The treatment of pediatric mandibular fractures is complex and requires careful consideration of various factors. Conservative management should be the first choice, with open reduction and internal fixation reserved for specific cases. The use of quartz splint fiber and ligature wire is an effective treatment option for stabilizing the mandible and providing occlusal stability in growing children. A fiber splint along with ligature wire can also be used as an alternative treatment to avoid any adverse effects on the growth and development of the mandible and permanent teeth. A multidisciplinary approach is essential to achieving the best outcomes for pediatric patients with mandibular fractures.

OBJECTIVE: 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.
METHODS: 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 14 days after surgery (T1), and at least 6 months 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.
RESULTS: 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.
CONCLUSIONS: 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.
CONCLUSIONS: 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.

OBJECTIVE: To evaluate the effects of a Twin-block appliance on the condyles of patients with ClassⅡmalocclusion by conducting a systematic review and a Meta-analysis.
METHODS: Pubmed, Embase, Cochrane Library, Chinese BioMedical Literature Database, China National Knowledge Infrastructure, and VIP Database were electronically searched. Randomized controlled trials, controlled clinical trials, and single-arm trials on condylar changes produced by a Twin-block appliance in patients with ClassⅡmalocclusion were included. Two reviewers independently extracted and assessed the risk of bias. Meta-analyses were conducted with Review Manager 5.3.
RESULTS: Eight studies were included; among which, seven were of high quality. After treatment with a twin block appliance, condyles moved anteriorly. The anterior joint spaces decreased (P<0.000 01), whereas the posterior spaces increased (P<0.000 01). The superior spaces were not changed (P=0.11). Moreover, a significant difference was observed in the increase of the condylar space index (P<0.000 01). After treatment, the anteroposterior diameters of the condyles and condylar height increased (P=0.000 2 and P<0.000 01, respectively). By contrast, no significant changes were discovered in the medial external diameters of the condyles (P=0.42).
CONCLUSIONS: A Twin-block appliance can promote the growth of a condyle in the posterior and upper direction and move it forward in favor of the correction of Class Ⅱ malocclusion.
目的: 评价Twin-block矫治器对安氏Ⅱ类错牙合患者髁突生长改建及位置的影响。方法: 计算机检索Pubmed、Embase、Cochrane library、中国生物医学文献数据库（CBM），中国知网（CNKI）、维普（VIP）等数据库，纳入所有应用Twin-block矫治器治疗安氏Ⅱ类错牙合畸形患者并对其髁突进行评估的随机对照试验、临床对照试验及单臂临床试验。2位评价者独立纳入文献、进行偏倚风险评估并提取数据，运用Revman 5.3软件进行统计分析。结果: 最终纳入文献8篇，共8项研究，其中7项为高质量研究。Meta分析结果显示：Twin-block矫治后，髁突向前移位，关节前间隙减小（P<0.000 01），关节后间隙增大（P<0.000 01），而关节上间隙未发现具有统计学意义的改变（P=0.11）；关节间隙指数的增大具有统计学意义（P<0.000 01）。治疗后髁突前后径增大（P=0.000 2），髁突高度增大（P<0.000 01），而髁突内外径的增大不具有统计学意义（P=0.42）。结论: Twin-block矫治器能够促进髁突向后上方的生长改建，并引导其向前移位从而使髁突-关节盘重新定位，达到良好的下颌位置并改善安氏Ⅱ类咬合关系。.