Pathophysiology and Pharmacologic Control of Osseous Mandibular Condylar Resorption

Evaluating changes in the condylar head after orthognathic surgery with or without articular disc repositioning: a systematic review

Failures in orthognathic surgery are associated with different factors, including those related to untreated or undiagnosed preoperative temporomandibular joint (TMJ) disorders. This systematic review aimed to assess potential alterations in the condylar head following orthognathic surgery. A systematic search for randomised controlled trials and retrospective studies was performed. For inclusion in the review, studies had to meet the following eligibility criteria according to the PICO framework: Patients: patients with orthognathic deformity and temporomandibular dysfunction (or temporomandibular osteoarthritis); Intervention: patients submitted to orthognathic surgery concomitantly with TMJ disjunction; Control: patients undergoing only orthognathic surgery with or without presurgical data; and Outcome: changes in temporomandibular joint position and volume. Nine studies met all the inclusion criteria and were selected for qualitative analysis. The results of this review show that simultaneous articular disc repositioning and orthognathic surgery provide better results in patients with preoperatively diagnosed condylar osteoarthritic changes. In conclusion, condylar remodelling (resorption/deposition) and its extent are determined by the direction of condylar displacement during surgery. Other factors such as age are also associated with the development of condylar resorption.

Temporomandibular joint surgery: the past, present, and future

Temporomandibular joint surgery for various pathological conditions and diseases affecting the integrity, mobility, and function of the joint has a long history. However, the greatest explosion of knowledge regarding the diagnosis and management of temporomandibular joint pain, pathology, and rehabilitation has occurred in the last 50 years. This review focuses on the incremental expansion of knowledge over time that led to the development of concepts that support our current surgical decisions and techniques, with the aim of identifying gaps in knowledge that require well-designed studies to move the field forward. Using this approach will allow an enhancement of our understanding of temporomandibular joint form and function, and enable focus to be placed on the evaluation, diagnosis, and non-surgical and surgical management strategies that are the most efficacious for our patients.

3D analysis of condylar and mandibular remodeling one year after intra-oral ramus vertical lengthening osteotomy

OBJECTIVES

Among the existing techniques for the correction of mandibular posterior vertical insufficiency (PVI), the intra-oral ramus vertical lengthening osteotomy (IORVLO) can be proposed as it allows simultaneous correction of mandibular height and retrusion. This study assessed the 3D morpho-anatomical changes of the ramus-condyle unit and occlusal stability after IORVLO.

MATERIALS AND METHODS

This retrospective analysis compared immediate and 1-year post-operative 3D CBCT reconstructions. The analysis focused on the condylar height (primary endpoint) and on the changes in condylar (condylar diameter, condylar axis angle) and mandibular (ramus height, Frankfort-mandibular plane angle, gonion position, intergonial distance, angular remodeling) parameters. Additionally, this analysis investigated the maxillary markers and occlusal stability.

RESULTS

On the 38 condyles studied in 21 included patients (mean age 23.7 ± 3.9 years), a condylar height (CH) loss of 0.66 mm (p < 0,03) was observed, with no correlation with the degree of ramus lengthening (mean 13.3 ± 0.76 mm). Only one patient presented an occlusal relapse of Class II, but a 3.4 mm (28%) condylar diameter loss and a 33% condylar volume reduction with loss of 1 mm and 3.4 mm in CH and condyle diameter, respectively. A mean 3.56 mm (p < 0.001) decrease in ramus height was noted, mainly due to bone resorption in the mandibular angles.

CONCLUSION

This study confirms the overall stability obtained with IORVLO for the correction of PVI.

CLINICAL RELEVANCE

This study aims to precise indication of IORVLO, and to validate the clinical and anatomical stability of results.

Conservative and minimally invasive approaches to control idiopathic condylar resorption: a scoping review

Idiopathic condylar resorption (ICR) is an uncommon disease with multiple names that challenges orthodontic and surgical treatments. The aim of this study was to investigate the existing conservative and minimally invasive approaches to controlling ICR. A scoping literature review was conducted. Inclusion criteria were young patients with degenerative joint disease based on the Research Diagnostic Criteria for Temporomandibular Disorders or Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) protocols, or ICR based on the DC/TMD expanded taxonomy protocol. Six electronic databases and the grey literature were searched, without restriction on year or language. Two reviewers independently performed the study selection and data extraction. Ten studies were selected from the 13,953 records identified. The total sample size was 424 patients; the female-to-male ratio was 7:1 and the mean age of the patients was 25.7 years. The main primary outcomes were pain, mandibular dysfunction, and condylar resorption. There is no guarantee of definitive success in the early management of ICR, despite the promising approaches studied, and there is no specific protocol to be followed. Therefore, close post-surgical follow-up is still required. This study highlights the need to standardize the nomenclature and diagnostic criteria, and assess the status of condylar activity/severity in future research.

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

BACKGROUND

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.

PURPOSE

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.

STUDY DESIGN, SETTING, AND SAMPLE

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.

PREDICTOR/EXPOSURE/INDEPENDENT VARIABLE

The primary predictor was the type of mandibular osteotomy, sagittal split osteotomy, and vertical ramus osteotomy.

MAIN OUTCOME VARIABLES

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

Covariates included patient age, sex, setback magnitude, temporomandibular joint symptoms, and fixation method for SSO patients.

ANALYSES

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.

RESULTS

The final sample comprised 30 condyles derived from 30 subjects. Mean age was 22.7 years (SD = 5.7) and mean setback was 3.9 mm (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 -60.9 mm3; 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.

CONCLUSIONS AND RELEVANCE

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.

Controversial Aspects of Diagnostics and Therapy of Idiopathic Condylar Resorption: An Analysis of Evidence- and Consensus-Based Recommendations Based on an Interdisciplinary Guideline Project

Idiopathic condylar resorption (ICR), though a rare event, is associated with severe detrimental sequelae for the patient. To date, the etiology remains unknown, and treatment strategies are highly controversial. Therefore, the aim of this study is to present an analysis of the consensus- and evidence-based approach to ICR by a German interdisciplinary guideline project of the AWMF (Association of the Scientific Medical Societies in Germany). Following a systematic literature search, including 56 (out of an initial 97) publications, with a predominantly low level of evidence (LoE), two independent working groups (oral and maxillofacial surgery and interdisciplinary, respectively) voted on a draft comprising 25 recommendations in a standardized anonymized and blinded Delphi procedure. While the results of the votes were relatively homogeneous, the interdisciplinary phase required a significantly higher number of rounds (p < 0.001). Most of the controversial recommendations were related to initial imaging (with consensus on CT/CBCT as the current diagnostic standard for imaging), pharmacotherapy (no recommendation due to lack of evidence), discopexy (no recommendation possible due to low LoE) and timing of orthognathic surgery (with consensus on two-staged procedures after invasive TMJ surgery, except for single-stage procedures if combined with total joint reconstruction). Overall, the Delphi procedure resulted in an interdisciplinary guideline offering the best possible evidence- and consensus-based expertise to date in the diagnosis and treatment of ICR.

Assessment of condylar positional changes in severe skeletal class II malocclusion after surgical-orthodontic treatment

OBJECTIVES

This study aimed to determine the positional changes in the condyle in the temporomandibular joint (TMJ) of severe skeletal class II malocclusion patients treated with surgical-orthodontics.

MATERIALS AND METHODS

The measurements of TMJ space in 97 severe skeletal class II malocclusion patients (20 males, 77 females, mean age, 24.8 years, mean ANB = 7.41°) were assessed using limited cone-beam computed tomography (LCBCT) images acquired before orthodontics (T0) and 12 months after surgery (T1). 3D remodeling of the TMJ and measurements of the anterior space (AS), superior space (SS), and posterior space (PS) were performed to determine the position of the condyle for each joint. All data were analyzed by t test, correlation analysis, and Pearson correlation coefficient.

RESULTS

The mean AS, SS, and PS values after the therapy changed from 1.684 to 1.680 mm (0.24%), 3.086 to 2.748 mm (10.968%), and 2.873 to 2.155 mm (24.985%), respectively. The decreases in SS and PS were statistically significant. Positive correlations were found in the mean AS, SS, and PS values between the right and left sides.

CONCLUSIONS

The combination of orthodontic and surgical treatment makes the condyle move counterclockwise in the TMJ in severe skeletal class II patients.

CLINICAL RELEVANCE

Studies of temporomandibular joint (TMJ) intervals changes in patients with severe skeletal class II after sagittal split ramus osteotomy (SSRO) are limited. The postoperative joint remodeling, resorption, and related complications remain unstudied.

Three-dimensional evaluation of mandibular condyle and coronoid process according to sex, age, and skeletal deformities

OBJECTIVE

To correlate the volume of the mandibular condyle (MC) and the coronoid process (CP) with sex, age, and skeletal deformities.

METHODS

The structures were visualized through semi-automatic segmentation of the 3D model and complemented with manual segmentation, using the ITK-SNAP 3.0 software. Mann-Whitney, Kruskal-Wallis, and the Dunn test were performed (p < 0.05).

RESULTS

The MC volume showed statistical differences between sex and skeletal deformities. Men and Class III patients showed higher values. CP volume was not influenced by age or skeletal deformities. However, statistical differences were found between sex, with higher values for men.

CONCLUSION

MC volume was influenced by sex and skeletal deformities, while CP was influenced only by sex. Women have smaller volumes for these structures. Age is not correlated with the volume of MC and CP. The highest and lowest values of condylar volume were found for Class III and II individuals, respectively.

Validity of IL-6 and Arthrocentesis in the Cause and Management of Internal Derangement of TMJ

Purpose

The aim of this clinical study was to evaluate the level of Interleukine-6 (IL-6), pre and post arthrocentesis to validate it as a biomarker in the Internal Derangement (ID) of TMJ.

Material and Methods

This study included 30 patients (20 females and 10 males) of Temporo-Mandibular Dysfunction (TMD) with Disc displacement without reduction (DDwoR) Wilkes stage III, who were refractory to conservative management. Arthrocentesis was performed as a therapeutic modality. Synovial fluid aspirates were obtained prior to arthrocentesis and post arthrocentesis with 300 ml of Ringer Lactate solution into the superior joint compartment for the assessment of level of IL-6. The clinical parameters used for correlating the level of IL-6 were degree of pain (VAS I), chewing ability (VAS II), Maximal Mouth Opening (MMO) in both pre and post op phase with the follow-up period of 01 day, 01 week, 01 month, 03 month and 06 month and the results were compared. ELISA was performed to analyze the levels of IL-6 in the aspirates. The clinical parameters and the level of IL-6 were recorded and analyzed statistically.

Results

The study showed ID of TMJ (Wilkes stage III) s are more prevalent in females especially in the fourth decades of life with the mean age of 38.4 years. The post operative assessment in terms of pain, maximum mouth opening, lateral movements of the mandible and the levels of IL-6 were found to be statistically significant with a P value <0.01.

Conclusion

This study validates the role of IL-6 as a definitive biomarker for the pathogenesis of ID of TMJ Wilkes stage III and arthrocentesis proved to be a minimally invasive therapeutic modality for its management.

Emerging pharmaceutical therapeutics and delivery technologies for osteoarthritis therapy

Osteoarthritis (OA) is one of the most common joint degenerative diseases in the world. At present, the management of OA depends on the lifestyle modification and joint replacement surgery, with the lifespan of prosthesis quite limited yet. Effective drug treatment of OA is essential. However, the current drugs, such as the non-steroidal anti-inflammatory drugs and acetaminophen, as well as glucosamine, chondroitin sulfate, hyaluronic acid, are accompanied by obvious side effects, with the therapeutic efficacy to be enhanced. Recently, novel reagents such as IL-1 antagonists and nerve growth factor inhibitors have entered clinical trials. Moreover, increasing evidence demonstrated that active ingredients of natural plants have great potential for treating OA. Meanwhile, the use of novel drug delivery strategies may overcome the shortcomings of conventional preparations and enhance the bioavailability of drugs, as well as decrease the side effects significantly. This review therefore summarizes the pathological mechanisms, management strategies, and research progress in the drug molecules including the newly identified active ingredient derived from medicinal plants for OA therapy, with the drug delivery technologies also summarized, with the expectation to provide the summary and outlook for developing the next generation of drugs and preparations for OA therapy.

Signs and Symptoms of Temporomandibular Dysfunction and Radiographic Condylar Morphology in Patients with Idiopathic Condylar Resorption

Background: Little is known about the clinical characteristics of idiopathic condylar resorption (ICR). The aim of this study was to examine the signs and symptoms of temporomandibular dysfunction (TMD) and evaluate the morphological characteristics of the condyles in patients with ICR. Methods: Sixty patients with ICR (41 in the bilateral ICR group and 19 in the unilateral ICR group) and forty-one healthy controls were examined. Signs and symptoms of TMD were described, and three-dimensional models of the condyles were measured and analyzed. Results: In total, 81.7% of ICR patients had self-reported symptoms and 78.3% of ICR patients had objective-found signs. The anteroposterior diameter, transverse diameter, height, maximal sectional area, volume of the condyles, axial angle, and the distance from the posterior point of the condyle to the Saggittal standard line were significantly smaller in the ICR condyles compared with the controls (p < 0.05). The condylar neck angle was significantly larger in the ICR condyles compared with the controls (p < 0.05). Conclusions: Most patients with ICR had signs and symptoms of TMD. The prevalence of clicking and opening−closing deviation was significantly different between the bilateral and the unilateral ICR groups. In patients with ICR, the size of the condyles decreased significantly; the condyles also rotated inward, moved forward, and inclined posteriorly.

Orthognathic surgery in patients with systemic diseases

PURPOSE

To review the experience with orthognathic surgery in patients with systemic diseases, syndromic conditions or an oncological history at a tertiary center.

METHODS

All patients who had undergone orthognathic surgery and all patients who were considered for orthognathic surgery between January 2013 and August 2020 at a tertiary center were retrospectively reviewed. Patients with cleft lip/palate and orthognathic patients requiring craniofacial surgery or reconstructive surgery were excluded. Patients with an underlying disorder were identified and divided into 3 categories: systemic disease, syndromic condition, or oncological disease treated with chemotherapy and/or radiation therapy of the head and neck. Data on intraoperative and postoperative complications until 3 months after surgery were collected for the patients who had undergone surgery. If orthognathic surgery was contraindicated, the reason was extracted from the patient's medical record.

RESULTS

Eighty out of 1049 orthognathic patients had an underlying disorder (7.6%), including 50 patients with at least one systemic disease, 25 patients with a syndromic condition, and 5 patients with an oncological disease. A complication was encountered in respectively 5 (10%), 9 (36%), and 0 (0%) patients. Three out of 1134 patients who consulted the multidisciplinary orthognathic-orthodontic consultation had a contraindication for orthognathic surgery because of an underlying disease (0.3%).

CONCLUSION

Based on our findings, intraoperative and short-term postoperative complications in patients with an underlying disorder are not frequent. Contraindications for orthognathic surgery because of a medical condition are very rare.

Condylar Reshape in Orthognathic Surgery: Morphovolumetric and Densitometric Analysis Based on 3D Imaging and Digital Workflow

Background

Condylar remodelling (CR) is a complex of phenomena that generates in response of the temporo-mandibular joint to forces and stress to maintain a morphological, functional and occlusal homeostasis. The most worrying aspect of the condylar reshape is the condylar resorption which implies fast loss of vertical dimension (>6% of pre-surgical value), mandibular retraction and open bite with preserved articular function.

Materials and Methods

Six parameters were analysed to study the condyles of twelve patients that underwent orthognathic surgery. The digital workflow was then described to make it reproducible enabling a more in-depth study of the reshaping processes that involving the condyle after a great stress like the surgery.

Results

The results of our study showed many statistically significant variations of the studied parameters. In all patients, it was noticed a decreased bone density (p = 0,002 per side).

Objectives

The aim of our study, with the aid of the contemporary 3D imaging and digital modelling and workflow technologies, is to investigate and analyse quantitatively and qualitatively the adaptative processes occurring in CR following bimaxillary repositioning. To the best of our knowledge, this is the only paper that investigates the CR considering six different variables at once.

Incidence and management of condylar resorption after orthognathic surgery: An overview

Objective

Condylar resorption (CR) is one of the major post-surgical complications of orthognathic surgery. This systematic review (SR) aimed to evaluate epidemiological data, risk factors, and therapeutical management of CR.

Methods

Six databases were screened by two investigators until September 2020 to obtain all SRs. After reading the titles and abstracts, eligible SRs were determined and data extraction was performed. Using the latest version of A Measurement Tool to Assess Systematic Reviews, the methodological quality of the included SRs was determined.

Results

Ten SRs with low or critically-low methodological quality were included in this review. Mandibular hypoplasia on the sagittal plane and hyperdivergent growth pattern on the vertical plane were the most common skeletal alterations in which CR could occur after orthognathic surgery. Post-operative condylar changes were analyzed both on two-dimensional and three-dimensional (3D) radiographic examinations. The incidence of CR was not related to the fixation method. Based on the severity of the pathological conditions, management of CR can include conservative or surgical therapy.

Conclusions

Despite the limited evidence in literature, CR is considered a consequence of orthognathic surgery. However, an accurate diagnosis of CR and a better orthognathic surgical planning must include 3D radiographic examinations to improve pre- and post-surgical comparison. Well-designed studies with long-term follow-up and 3D data are needed to clarify the findings of this analysis..

C-Reactive Protein Knockout Attenuates Temporomandibular Joint Inflammation in Rats

BACKGROUND

C-reactive protein (CRP), a biomarker of inflammation, is highly expressed in osteoarthritis- (OA-) related diseases, but its exact role remains unknown. In this study, we evaluated the biological effect of CRP on temporomandibular joint (TMJ) inflammation.

METHODS

Freund's complete adjuvant (CFA) was used to induce TMJ inflammation in CRP-knockout (CRP-/-) and control rats. Degenerative changes in the TMJ were compared to elucidate the role of CRP in TMJ inflammation. In addition, inflammatory cytokines, macrophage activation, and osteoclast differentiation were evaluated by real-time quantitative polymerase chain reaction, immunohistochemistry, and tartrate-resistant phosphatase staining to explore the potential regulatory mechanism.

RESULTS

Compared to the control, CFA induced TMJ inflammation, which increased systemic and local CRP expression. Furthermore, CRP-/- rats exhibited less severe inflammatory symptoms. The downregulation of proinflammatory cytokines (interleukin- (IL-) 1β and IL-6) and upregulation of the anti-inflammatory cytokine IL-10 were detected in CRP-/- rats, which also exhibited reduced macrophage activation and osteoclast differentiation.

CONCLUSION

These results indicated that controlling the highly elevated levels of CRP during inflammation could modify the cytokine profile, macrophage activation, and osteoclast differentiation, thus, providing beneficial effects for TMJ-OA prevention and treatment.

[Condylar displacement following orthognathic surgery]

The overview of the current literature in the research of mandibular condyle displacement after orthognathic surgeries was done. The correct postoperative mandibular condyle position is considered as one of the determinants of the stability of treatment results.

Omega 3 polyunsaturated fatty acids: Potential anti-inflammatory effect in a model of ovariectomy and temporomandibular joint arthritis induction in rats

OBJECTIVE

To evaluate the effect of polyunsaturated fatty acid-type omega 3 (ω3) on the temporomandibular joint (TMJ) of ovariectomized rats (OVX) with rheumatoid arthritis (RA).

DESIGN

Rheumatoid arthritis was induced using complete Freund's adjuvant and type II bovine collagen injected at the base of the tail. Twenty-four adult female rats were treated by gavage and divided into four groups: G1: Sham, treated with 0.9% NaCl; G2: OVX, treated with 0.9% NaCl; G3: OVX+RA treated with 0.9% NaCl; G4: OVX+RA+ω3 treated with omega 3 (300 mg/kg/day). The induction of rheumatoid arthritis in groups G3 and G4 was performed 21 days after OVX, treatments were started 15 days after the induction of rheumatoid arthritis, maintained for 7 days, and killed. Bilateral TMJs were removed and assigned to morphometric analysis by micro-computed tomography and immunoassay to assess levels of cytokines IL-1β, IL-6, TNF-α, and IL-10.

RESULTS

Higher levels of inflammatory cytokines were found in the G2 and G3 (P < 0.05) and anti-inflammatory cytokines in the G1 and G4. TMJ analysis by micro-computed tomography showed a higher percentage of bone volume (median - interquartile deviation) in G1 (96.2-1.1) than in the G2 (91.5-2.0, P = 0.0374) and G3 (85.1-5.2, P = 0.0001) but showed no statistically significant differences with the G4 (93.1-1.7, P = 0.79).

CONCLUSIONS

Omega 3 successfully reduced TMJ damage in rats caused by ovariectomy and induced rheumatoid arthritis, and is a promising alternative for bone repair and attenuation of inflammatory processes.

Imaging of the Postoperative Jaws and Temporomandibular Joints

Surgical procedures in the oral cavity and maxillofacial complex are diverse and involve multiple tissues unique to this region. These procedures are used to remove pathology and infection, restore function, optimize occlusal relationships, prosthetically replace teeth and temporomandibular joints, improve esthetics, and increase upper respiratory tract dimensions. Procedures in the oral cavity are often complicated by infection stemming from the naturally occurring oral flora, but can also be complicated iatrogenically. This article explores the more commonly encountered surgical procedures through examination of the indications, anatomy to consider, and the radiographic imaging of success and failure of these procedures.

Orthognathic surgery for juvenile idiopathic arthritis of the temporomandibular joint: a critical reappraisal based on surgical experience

Juvenile idiopathic arthritis (JIA) involving the temporomandibular joint (TMJ) can result in significant dentofacial deformities that may require orthognathic surgical correction. The aim of this study was to assess the functional and aesthetic results relative to stability after bimaxillary surgery with counterclockwise rotation of the occlusal plane in patients with JIA. A retrospective chart review was conducted of all patients affected by JIA who underwent orthognathic surgery between January 2000 and December 2019 at the Face Surgery Centre (Parma, Italy). Patient records were evaluated for surgical indications, complications, and outcomes. The final study sample included 13 patients (12 female, one male). The mean age of the patients was 18.6 years (range 17-26 years) at the time of surgery; 12 patients had bilateral TMJ disease. At the 1-year follow-up, all patients except one had a stable occlusion with a natural, well-balanced morphology of the face and adequate dynamic excursion of the mandible. The 1-year postoperative cone beam computed tomography (CBCT) scan revealed complete ossification at all osteotomy sites. Bilateral sagittal split osteotomy with mandibular advancement is an effective procedure with a low rate of complications for patients with JIA with stable disease confirmed by preoperative CBCT or magnetic resonance imaging.

Three-dimensional analysis of condylar remodeling and skeletal relapse following LeFort-I osteotomy: A one-year follow-up bicenter study

The aim of the study was to quantify the postoperative condylar remodeling after Le Fort I surgery. Patients treated with a Le Fort I osteotomy were investigated. CBCT scans were acquired preoperatively, one week and one year postoperatively. A preoperative 3D cephalometric analysis was performed on the preoperative CBCT. Surgical movements were quantified using a voxel-registration based method (OrthoGnaticAnalyser). After rendering of the condyles from the CBCT, a volumetric analysis was performed. The correlation between the surgical movement of the maxilla and the postoperative condylar volume changes was determined with analysis of variance. RESULTS: A total of 45 subjects were included in this study. 47 of 90 condyles (52%) showed a mean volume reduction of 93 mm³ (4.9 volume-%) postoperatively. The maxilla was impacted in 12 patients (2.44 ± 2.49 mm) and extruded in 33 patients (1.78 ± 1.29 mm). The maxillary impaction group showed a volume reduction of 50 ± 122 mm³ and the extrusion group showed a mean volume gain of 21 ± 139 mm³ (p = 0.028). CONCLUSION: Clinicians should be aware of potential condylar remodeling following solitary Le Fort I osteotomies, particularly in female patients with maxillary impaction.

The effect of association of aspirin and omega 3 in rat temporomandibular joint with induced arthritis

This study aimed to evaluate the effects of omega-3 (ω3) polyunsaturated fatty acids, in association with aspirin (AA), on the morphology of cytokine release in the temporomandibular joint (TMJ) of rats induced with rheumatoid arthritis (IR) by injecting 100 μL of complete Freund's adjuvant with bovine type II collagen at the tail base. Thirty-two adult male rats were divided into treatment groups: Sham, treated with 0.9% sodium chloride (NaCl) p.o.; IR-control, treated with 0.9% NaCl p.o.; IR-ω3 treated with ω3 PUFAS (85 mg/kg/day p.o.); and IR-ω3 + AA treated with ω3 (85 mg/kg/day p.o.) + AA (20 mg/kg/day i.p.). After maintained treatment for seven days, the animals were euthanized. Bilateral TMJs from each rat were removed and one was subjected to histological immunoassays and enzyme-linked immunosorbent assays to assess interleukin (IL)-1β, tumor necrosis factor-α, and IL-10 levels. Data analysis was performed using the Kruskal-Wallis and Dunn tests. In the IR-ω3 and IR-ω3 + AA groups, the TMJ was greater than in the IR-control group (P < 0.0001). The addition of AA did not improve the effects of ω3 (P = 0.0698). Similarly, the addition of AA conferred no additional effects on the cytokine levels (P > 0.05); however, it increased the proteoglycan density, compared with ω3 alone. We found that ω3 exhibited anti-inflammatory activity in arthritic rats, and the addition of AA increased proteoglycan density, but did not affect cytokine expression.

Mandibular condyle displacements after orthognathic surgery-an overview of quantitative studies

The repositioning of bone segments during orthognathic surgeries often results in mandibular condyle positional changes and can also affect jaw muscles, soft tissues and the temporomandibular joint (TMJ). Condylar displacements are considered as one of the factors of bone remodeling and further skeletal relapse. The quantitative approach is commonly used in comparative analyses and evaluations of the relationships between examined factors. The aim of this study is the overview of the current literature including quantitative analysis in the research of mandibular condyle positional changes as a consequence of orthognathic surgeries. Thirty articles were included in the overview. Most of the articles present a comparative and evaluative analysis of treatment results concerning different surgical approaches, fixation methods or types of skeletal defects. The correlation between condylar displacements and bone remodeling, skeletal relapse and TMJ dysfunctions were considered. The most frequently repeated study variables were: short-term changes, Class III malocclusion, yaw rotation, 3D cephalometry measurements. Quantitative data might be useful in the evaluation of patterns and range of condylar displacements for specific treatment conditions. Available literature concerning the analysed topic is characterized by great heterogeneity with regards to the purpose and methodologies of the studies. More systematic approaches and long-term considerations are needed in future research.

The efficacy of mesenchymal stem cells in regenerating structures associated with the temporomandibular joint: A systematic review

OBJECTIVES

The objective of this systematic review is to evaluate the role of mesenchymal stem cells in the regenerative treatment of temporomandibular joint resorption.

DESIGN

Search strategies were performed in the following databases: PubMed/MEDLINE, EMBASE, Cochrane Collaboration Library, and Web of Science. Two independent reviewers selected the included articles using a two-phase process based on the eligibility criteria. The reviewers independently collected the required information from the included articles. The methodological quality of the selected studies was assessed individually.

RESULT

In accordance with the inclusion and exclusion criteria, 703 studies were found and 8 articles were included. Thus, six studies using animal models and two human studies were included in this systematic review.

CONCLUSION

Based on the data of our systematic review, the use of mesenchymal stem cells is a promising method for the repair and regeneration of temporomandibular joint components.

One-year stability of the mandibular advancement and counterclockwise rotation for correction of the skeletal class II malocclusion and high mandibular plane angle: Dental and skeletal aspect

Background

The purpose of this study was to evaluate the stability on dental and skeletal aspect after surgical advancement and counterclockwise rotation for the correction of the mandibular deficiency in patients with high mandibular plane angle (MPA).

Methods

We analyzed the records of patients who had undergone surgical treatment for dentofacial deformities with mandibular deficiency and high MPA. Clinical and radiological data were taken 1 month before surgery (T0), 6 weeks after surgery (T1) and 1 year after surgery (T2). Cephalometric values of the MPA were recorded and compared. The cephalometric changes in the different time periods were defined as follows: A: postsurgical changes (T0–T1), B: one-year changes (T1–T2), and C: short term changes (T0–T2).

Results

Twenty-seven patients had prominent mandibular deficiency with an MPA of over 35° (high angle). The mean age of patients at surgery was 29.7 years. Seven patients had a single jaw procedure, 20 patients had bilateral sagittal split osteotomy (BSSO) combined with a Le Fort I osteotomy, and 14 patients had additional genioplasty. MPA values differed significantly between the time periods (p < 0.05) with an observed relapse of the angle. However, satisfactory clinical improvement was achieved in the dental and skeletal presentation. The overjet improvement was evident from 8.815 ± 2.085 mm (T0) to 3.426 ± 1.253 mm (T2).

Conclusion

Counterclockwise surgical advancement of the mandible to correct mandibular deficiency in patients with a high mandibular plane angle showed an overall acceptable stability during one-year follow-up.

Low skeletal bone mineral density as a potential aetiological factor towards idiopathic condylar resorption

The aim of this study was to investigate the contributing factor of impaired skeletal quality in the pathogenesis of idiopathic condylar resorption (ICR). One hundred and twenty-six patients with MRI-confirmed ICR and 596 patients with disc displacement (DD) without a diminished condyle, of both sexes, were included. Dental examinations and retrospective surveys regarding temporomandibular joint symptoms and progression of maxillofacial deformities were conducted. Skeletal bone mineral density (BMD) was measured by dual energy X-ray absorptiometry (DXA) and converted to T-scores and Z-scores. Results showed that ICR patients had a smaller overbite (1.56±3.3 vs 3.05±2.0mm), larger overjet (4.9±2.4 vs 3.5±1.9mm), larger range of mouth opening (36.5±6.7 vs 33.6±7.1mm), and higher rates of anterior open bite and mandibular retrusion compared to DD patients (all P<0.001). ICR was associated with an increased probability of low skeletal BMD at chronological age in females (P=0.020) but not in males (P=0.095). This study indicates that reduced BMD may predispose females to an exacerbated condylar resorption process in addition to increased joint loading initiated from DD.

Combined orthodontic and surgical treatment for a patient with Hallermann-Streiff-Francois syndrome, severe obstructive sleep apnea, and history of antiresorptive medication

Micrognathia and retrognathia, as observed in patients with the Hallermann-Streiff-Francois syndrome, might result in obstructive sleep apnea syndrome. When it becomes severe (apnea-hypopnea index [AHI], ≥30), noninvasive treatment options might be insufficient. An orthognathic treatment with mandibular advancement will increase the upper airway volume, which results in a decrease of apneas. A 53-year-old woman with Hallermann-Streiff-Francois syndrome and a history of antiresorptive medication suffered from severe obstructive sleep apnea (AHI, 77.7). She was treated with a combined orthodontic and surgical approach. The AHI decreased to 1, and the patient felt fitter after treatment. No medication-induced osteonecrosis nor inhibition of tooth movement was seen. A combined orthodontic and surgical treatment of a patient with severe obstructive sleep apnea was a good treatment choice. With a history of antiresorptive medication, the risks related to these medications have to be weighed up against the consequences of not treating obstructive sleep apnea syndrome. With a drug holiday, successful surgical treatment can be achieved.

Overexpression of MMPs, cytokines, and RANKL/OPG in temporomandibular joint osteoarthritis and their association with joint pain, mouth opening, and bone degeneration: A preliminary report

OBJECTIVE

This study aimed to determine the expression of distinct matrix metalloproteinases, cytokines, and bone resorptive factors in temporomandibular joint osteoarthritis (TMJ-OA) patients and their association with joint pain, mouth opening, and subchondral bone degeneration.

MATERIALS AND METHODS

Twelve patients affected with TMJ-OA (n = 5), disk displacement without reduction (DDWoR) (n = 3), or disk displacement with reduction (DDWR) (n = 4) were selected. Joint pain was quantified by using visual analog scale, mouth opening was quantified at the maximum pain-free aperture, and bone degeneration was quantified using joint imaging. Synovial fluid samples were collected and immediately processed for cell and synovial fluid recovering. From cells, the MMP-1, MMP-2, MMP-8, MMP-13, IL-6, IL-23, and TNF-α expression was quantified by qPCR. From synovial fluid, the RANKL and OPG levels were quantified by ELISA.

RESULTS

Higher levels of MMP-1, MMP-8, MMP-13, IL-6, IL-23, TNF-α, and RANKL/OPG ratio were detected in TMJ-OA compared with DDWoR and DDWR patients (p < .05). Joint pain significantly correlated with TNF-α levels (r = .975, p = .029). Besides, imaging signs of bone degeneration significantly correlated with RANKL/OPG ratio (r = .949, p = .042). Conversely, mouth opening did not correlate with any of the analyzed mediators.

CONCLUSION

During TMJ-OA, a pathological response characterized by the overexpression of TNF-α and RANKL/OPG could be involved in joint pain and subchondral bone degeneration.

Influence of oestrogen deficiency and excessive mechanical stress on condylar head of mandible

OBJECTIVE

We assessed the aetiology of idiopathic condylar resorption by examining the effects of oestrogen and compressive mechanical stress under a low systemic oestrogen condition in temporomandibular joints (TMJ) caused by an ovariectomy.

MATERIALS AND METHODS

Female rabbits were divided into non-ovariectomy (non-OVX) and ovariectomy (OVX) groups. A cortical osteotomy was performed with a custom device that was increased in length by 0.25 mm every 12 hr for 1 week after the operation, during which the TMJs in the rabbits received compressive mechanical stress. Samples from both groups were examined with micro-computed tomography and histological staining.

RESULTS

Area and depth of bone resorption were both greater in the OVX group. Furthermore, a significantly earlier and greater prevalence of sub-condylar bone resorption was noted in that group, while cells positive for tartrate-resistant acid phosphatase were increased in the OVX group.

CONCLUSIONS

The present findings suggest that oestrogen induced a much greater amount of bone resorption on the anterior surface of the condylar head at an earlier stage in the TMJs of the present model rabbits. Thereafter, restoration of TMJ function appeared to occur in a normal manner.

Knockdown of long non‑coding RNA AK094629 attenuates the interleukin‑1β induced expression of interleukin‑6 in synovium‑derived mesenchymal stem cells from the temporomandibular joint

Interleukin (IL)‑1β is a key promotor in the pathogenesis of temporomandibular joint osteoarthritis. Differentiation of stem cells to cartilage is a crucial repair mechanism of articular cartilage damage, and IL‑1β has been reported to impede the differentiation by upregulating the secretion of IL‑6, an important inflammatory factor. Long non‑coding RNAs (lncRNAs) regulate a number of physiological and pathological processes, but whether lncRNA AK094629 contributes to the IL‑1β mediated induction of inflammation remains unclear. Therefore, the aim of the present study was to investigate the effect of AK094629 on IL‑1β‑induced IL‑6 expression in synovial‑derived mesenchymal stem cells (SMSCs) of the temporomandibular joints. The results of the present study demonstrated that the expression of AK094629 in the synovial tissue of patients with osteoarthritis was positively correlated with IL‑1β. In addition, IL‑1β upregulated the expression of AK094629 in the SMSCs in vitro, and AK094629 knockdown inhibited the IL‑1β mediated upregulation of IL‑6. The present study also demonstrated that AK094629 knockdown downregulated the expression of the mitogen‑activated protein kinase kinase kinase 4 (MAP3K4), which is upregulated by IL‑1β, whereas knockdown of MAP3K4 did not affect the expression of AK094629, but reversed the upregulation of IL‑6 in SMSCs. In conclusion, AK094629 knockdown attenuated the expression of IL‑1β‑regulated IL‑6 in the SMSCs of the temporomandibular joint by inhibiting MAP3K4. Therefore, AK094629 may be a potential novel therapeutic target for the treatment of temporomandibular joint osteoarthritis.

Ahmad WMA, Ahmed Asif J, Khoo SP, Husein A, Ab-Ghani Z, Kassim NK. Biomarkers for Temporomandibular Disorders: Current Status and Future Directions

Numerous studies have been conducted in the previous years with an objective to determine the ideal biomarker or set of biomarkers in temporomandibular disorders (TMDs). It was recorded that tumour necrosis factor (TNF), interleukin 8 (IL-8), IL-6, and IL-1 were the most common biomarkers of TMDs. As of recently, although the research on TMDs biomarkers still aims to find more diagnostic agents, no recent study employs the biomarker as a targeting point of pharmacotherapy to suppress the inflammatory responses. This article represents an explicit review on the biomarkers of TMDs that have been discovered so far and provides possible future directions towards further research on these biomarkers. The potential implementation of the interactions of TNF with its receptor 2 (TNFR2) in the inflammatory process has been interpreted, and thus, this review presents a new hypothesis towards suppression of the inflammatory response using TNFR2-agonist. Subsequently, this hypothesis could be explored as a potential pain elimination approach in patients with TMDs.

Mouth breathing impairs the development of temporomandibular joint at a very early stage

OBJECTIVES

The study aimed to explore the effects of mouth breathing and hypoxia on the condyle of temporomandibular joint (TMJ) via two animal models.

METHODS

24 four-week-old rats were randomly separated into three groups, consisting of eight control rats, eight intermittent hypoxia (IH) rats, and eight intermittent nasal obstruction (INO) rats. We use the IH model and the INO model to simulate children suffering from hypoxia and mouth breathing. After 16 days, the condyle of TMJ and surrounding white adipose tissue (WAT) and skeletal muscle tissue were obtained for further staining and qRT-PCR. Finally, RNA-seq was used to verify the results.

RESULTS

The intermittent hypoxia cannot significantly change the overall structure in the cause of short-term hypoxia stimulation, but the intermittent nasal obstruction can alter the condyle, WAT, and muscle, while also introducing noticeable structural changes in tissue hypoxia and macrophage infiltration. Sequencing data verified these findings and also suggested that this process might involve the Hif-1α/Vegf axis.

CONCLUSIONS

Our findings reveal the very early structural impact of mouth breathing on condyle reconstruction in rat models, and hypoxia does not induce evident alteration on condyle. However, since these results are mainly focused on rats, further studies are needed to understand its effects on humans.

Do Patients With Different Mandibular Plane Angles Have Different Time to Relapse After Bilateral Sagittal Osteotomy With Mandibular Advancement?

PURPOSE

This study sought to answer the following question: Do patients with different mandibular plane angles (MPAs) have a different time to relapse after mandibular advancement with bilateral sagittal split osteotomy?

MATERIALS AND METHODS

We performed a retrospective cohort study of patients who underwent bilateral sagittal split osteotomy advancement at Massachusetts General Hospital between 2005 and 2017. The primary predictor variable was MPA, categorized as low (<25°), medium (between 25° and 35°), or high (>35°). The outcome variable was time to relapse (≥2-mm posterior change at the B point). Other covariates included gender, age, temporomandibular joint symptoms, bimaxillary surgery, direction of mandibular rotation, magnitude of advancement, genioplasty, and fixation method. Time to relapse was estimated using the Kaplan-Meier method. Cox and parametric regressions for interval-censored data were performed. P < .05 was considered statistically significant.

RESULTS

The sample was composed of 58 patients (40 female patients), with a mean age of 26.1 ± 4.9 years, grouped as follows: low MPA, n = 15; medium MPA, n = 26; and high MPA, n = 17. Clinically significant relapse was found in 18 patients (31%). Age, temporomandibular joint symptoms, counterclockwise rotation, and magnitude of advancement were statistically significantly different among the 3 groups. When we assessed time to relapse, the Kaplan-Meier method showed that high-MPA patients had a longer mean time at risk and higher estimated probabilities of relapse at different time points compared with low- and medium-MPA patients (P < .05). However, this association was not significant in Cox and parametric regressions.

CONCLUSIONS

Our results suggest that clinically significant relapse was found during the first postoperative year in low-MPA patients and from 2 to 5 years postoperatively in high-MPA patients. Multivariate regression analyses did not show a significant association between MPA and time to relapse, suggesting that other covariates may play a role in the observed time to relapse.

The Biomechanical Effect of the Sagittal Split Ramus Osteotomy on the Temporomandibular Joint: Current Perspectives on the Remodeling Spectrum

The sagittal split ramus osteotomy is a key approach for treating dentofacial deformities. Although it delivers excellent results, the sagittal split ramus osteotomy is believed to induce stress to the temporomandibular joint. Potential stress inducers could be classified as intra- and postoperative factors resulting in an inflammatory response and molecular cascades, which initiate physiological remodeling. Occasionally, this process exceeds its capacity and causes pathological remodeling, through either degenerative joint disease or condylar resorption. Hard evidence on how orthognathic surgery causes inflammation and how this inflammation is linked to the spectrum of remodeling remains scarce. Current concepts on this matter are mainly based on clinical observations and molecular mechanisms are extrapolated from fundamental research in other body parts or joints. This perspective study provides an overview of current knowledge on molecular pathways and biomechanical effects in temporomandibular joint remodeling. It provides research directions that could lead to acquiring fundamental evidence of the relation of orthognathic surgery and inflammation and its role in remodeling. Performing osteotomies in animal models and identifying inflammatory mediators as well as their effect on the joint seem promising. Patients affected by pathological remodeling can also provide samples for histological as well as molecular analysis. Individual susceptibility analysis by linking certain suspect phenotypes to genetic variation could identify the cause and molecular pathway responsible for degenerative joint disease and condylar resorption, ultimately leading to clinically applicable treatment and prevention strategies.

Condylar dysfunctional remodeling and recortication: a case-control study

BACKGROUND

Temporo-mandibular disorders (TMD) is a collective term comprehending different clinical issues involving masticatory muscles, temporo-mandibular joint (TMJ) and other associated structures. TMD diagnosis is not made for its pathogenesis or etiology, but mainly on clinical symptoms. Primary dysfunction develops mostly on four factors: individual predisposition, high psychomotor activity (due to stress or parafunction), occlusal instability and low or absent tissue adaptation capability. On the other hand, secondary disorders can be caused by hereditary or congenital diseases, rheumatic inflammatory diseases, autoimmune and tumoral diseases. During their function, the condyles undergo a structural adaptive and physiological remodeling, but when mechanical stress exceeds adaptive capability, dysfunctional remodeling phenomena may occur. It is characterized by significant condylar morphological modifications at the level of the head of the condyle (smaller condyle), break of cortical integrity and reduced mandibular ramus height with subsequent mandibular retrusion and articular function alteration. The aim of this study is to compare condylar recortication amount, and pain reduction after two different therapeutic protocols.

METHODS

This is a case-control study. Twenty TMD patients were chosen and each of them underwent a documentation protocol including extraoral and intraoral photographs, dental casts, casts mounting on the articulator to evaluate CPI (CO-CR discrepancy index) and cone beam computed tomography (CBCT) of the mandibular condyles taken in closed mouth position. For the radiographic evaluation, a Planmeca ProMax 3D Mid system was utilized with an acquiring volume of 80×80 mm dimension, exposition 90 kV, 10.0 mA, 12 seconds with a DAP (Dose Area Product) of 1094 mGy·cm2 for each condyle. The acquired volume was elaborated by the Planmeca Romexis software v. 3.2.0.R and TMJ module. Seven coronal cuts and 10 sagittal cuts were performed on the head of the condyle to highlight the amount of cortication, before and after the application of two different therapeutic protocols. Protocol number 1 (N.=10 patients) included the exclusive use of a splint, while protocol number 2 (N.=10 patients) included the use of a splint associated with pharmacological therapy (NSAIDs, antioxidant, omega 3). The revaluation was performed on asymptomatic patient after a period of 6-8 months. The pain for each patient was assessed by a Visual Analogue Scale (VAS) from 0 to 10, 0 meaning no pain and 10 the worst pain ever felt. The VAS was evaluated after 10 days from the beginning of the treatment, after 3 months and after 8 months at the end of the treatment. Statistical analyses were carried using a χ2 test (P value <0.05).

RESULTS

No significant differences in the amount of cortication were found in the radiographic revaluation between the two different therapeutic protocols, even though it was noticed that the use of medicaments brought to a resolution of the symptoms in a shorter period of time (P=0.00001 after 10 days; P=0.0251 after 3 months).

CONCLUSIONS

According to this study, pharmacological protocol in the therapy of TMD does not seem to affect condylar cortication. Medicaments although seem to accelerate the disappearance of clinic symptomatology, but more researches are needed to valid these findings.