Condylar Remodeling Research Articles

Condylar resorption after orthognathic surgery: A systematic review

Condylar resorption after orthognathic surgery (CROS) represents a progressive alteration of shape and volume of the mandibular condyle. It is a known factor of surgical relapse. The aim of this systematic review was to discuss the physiopathology, mechanisms, risk factors, diagnosis and treatment of this disease. A systematic review of the literature was performed on the Pubmed database from 1970 to 2014, using following terms: ("orthognathic surgery") AND ("condylar resorption" OR "progressive condylar resorption" OR "idiopathic condylar resorption" OR "condylar atrophy" OR "condylolysis"). Papers were included according inclusion and exclusion criterias. The search leaded to 32 articles. Seventeen were included. CROS was a condylar remodeling secondary to an imbalance between mechanical stress applied to the temporomandibular joints (TMJ) and the host adaptive capacities. It mainly occurred in 14 to 50years old women with pre-existing TMJ dysfunction, estrogen deficiency, class II malocclusion with a high mandibular plane angle, a diminished posterior facial height and a posteriorly inclined condylar neck. Mandibular advancement superior to 10mm, counterclockwise rotation of the mandible and posteriorly condylar repositioning were associated with an increased risk of CROS. Treatment consists in re-operation in case of degradation of the occlusal result after an inactivity period of at least 6 months. Condylectomy with allogenic or autologous reconstruction is an alternative. Prevention is crucial and requires at-risk patient information.

The role of mandibular proximal segment rotations on skeletal relapse and condylar remodelling following bilateral sagittal split advancement osteotomies.

To quantify the postoperative rotation of the proximal segments in 3D and to assess its role on skeletal relapse and condylar remodelling following BSSO advancement surgery. 56 patients with mandibular hypoplasia who underwent BSSO advancement surgery were enrolled into the study. A CBCT scan was acquired preoperatively, at one week postoperatively and at one year postoperatively. After segmentation of the facial skeleton and condyles, 3D cephalometry and condylar volume analysis were performed. A mean mandibular advancement of 4.6 mm was found. 55% of the condyles decreased in volume postoperatively, with a mean reduction of 6.1 volume-percent. Among 11 patients who exhibited a clinically significant relapse of more than 2 mm, 10 patients exhibited a counterclockwise rotation of the proximal segments. The odds of skeletal relapse (>2 mm) was 4.8 times higher in patients whose proximal segments were rotated in a counterclockwise direction. Postoperative flaring (3.3 mm) and torque (0.3°) were, however, not associated with skeletal relapse or condylar remodelling. Gender, preoperative condylar volume, postoperative condylar remodelling, counterclockwise rotation of the proximal segment and the amount of surgical advancement were prognostic factors for skeletal relapse (r(2) = 0.83). The role of the mandibular plane angle in relapse is questionable.

Installing and thereafter removing an aberrant prosthesis elicited opposite remodelling responses in growing mouse temporomandibular joints.

Temporomandibular joint (TMJ) displays a high remodelling capability. The current purpose was to investigate the differences between mandibular condylar remodelling responses of growing mice to installation and removal of unilateral anterior crossbite (UAC) prosthesis. Twenty-four mice were divided into one mock control group and two UAC groups. Unilateral anterior crossbite was created by installing a pair of prosthesis to left-side maxillary and mandibular incisors. Unilateral anterior crossbite was removed in removal group at 3 weeks but remained in UAC group. Temporomandibular joints were sampled at 7 weeks. Changes in condylar cartilage and subchondral bone were assessed by histology and in vivo micro-CT. Real-time PCR and immunohistochemistry were performed to evaluate expression changes in ADAMTS-5, MMP-3, MMP-9, MMP-13, IL-1, TNF-α, OPG and RANKL. Statistical analysis was performed at α = 0.05. Temporomandibular joint cartilage degradation was induced by UAC as previously reported but was reversed by removal of UAC. The dropped cartilage thickness, chondrocyte number and collagen II-positive area, the increased expression levels of Adamts-5, Mmp3, 9, 13, Tnf-α and Il-1β in cartilage, the decreased ratio of OPG/RANKL in both condylar cartilage and subchondral bone, the loss of TMJ subchondral bone and the increase in the TRAP-positive cells in subchondral bone were all reversed in the removal group (P < 0.05). The growing mouse TMJ condyle displays a high remodelling capability which can be degenerative and rehabilitative, respectively, in response to placement and thereafter removal of the aberrant prosthesis. Eliminating aberrant prosthesis is helpful to promote the degraded condyle to recover.

Condylar and occlusal changes after high condylectomy and orthodontic treatment for condylar hyperplasia.

Condylar hyperplasia (CH) of human temporomandibular joint (TMJ) often occurs unilaterally, and causes occlusal disturbance and facial asymmetry. The purpose of this study was to compare the effects of high condylectomy with and without postsurgical orthodontic treatment. Forty patients were diagnosed as having active CH and treated with high condylectomy. Patients in group A (n=24) took the postsurgical orthodontic therapy immediately after surgery, and those in group B (n=16) did not take orthodontic therapy. For both groups, the mandibular ramus height on the affected side was decreased significantly after surgery. Orthodontic treatment promoted maxillary alveolar remodeling significantly by depressing alveolar bone of the affected side and increasing alveolar bone of the nonaffected side. Better improvement for facial midline deviations was observed in group A than in group B. In both groups, the condylar remodeling was observed and manifested by the smoothening of condylar surface and returning of condyle to normal position in glenoid fossa. It was concluded that high condylectomy in the treatment of active CH of TMJ improved the functional occlusion and facial aesthetic. Postsurgical orthodontic therapy could more effectively enhance maxillary alveolar and condylar remodeling, and more rapidly and meticulously establish the stable occlusal and normal position of condyle than the spontaneous remodeling.

3D analysis of condylar remodelling and skeletal relapse following bilateral sagittal split advancement osteotomies

A major concern in mandibular advancement surgery using bilateral sagittal split osteotomies (BSSO) is potential postoperative relapse. Although the role of postoperative changes in condylar morphology on skeletal relapse was reported in previous studies, no study so far has objectified the precise changes of the condylar volume. The aim of the present study was to quantify the postoperative volume changes of condyles and its role on skeletal stability following BSSO mandibular advancement surgery. A total of 56 patients with mandibular hypoplasia who underwent BSSO advancement surgery were prospectively enrolled into the study. A cone beam computed tomography (CBCT) scan was acquired preoperatively, at 1 week postoperatively and at 1 year postoperatively. After the segmentation of the facial skeleton and condyles, three-dimensional cephalometry and condylar volume analysis were performed. The mean mandibular advancement was 4.6 mm, and the mean postoperative relapse was 0.71 mm. Of 112 condyles, 55% showed a postoperative decrease in condylar volume, with a mean reduction of 105 mm3 (6.1% of the original condylar volume). The magnitude of condylar remodelling (CR) was significantly correlated with skeletal relapse (p = 0.003). Patients with a CR greater than 17% of the original condylar volume exhibited relapse as seen in progressive condylar resorption. Female patients with a high mandibular angle who exhibited postoperative CR were particularly at risk for postoperative relapse. Gender, preoperative condylar volume, and downward displacement of pogonion at surgery were prognostic factors for CR (r2 = 21%). It could be concluded that the condylar volume can be applied as a useful 3D radiographic parameter for the diagnosis and follow-up of postoperative skeletal relapse and progressive condylar resorption.

Stomatognathic function and image evaluation for Angle ClassII Division 2 case with marked condylar remodeling

Stomatognathic function and image evaluation for Angle ClassII Division 2 case with marked condylar remodeling

Changes in expression of phospholipase C-gamma1(tyr783) in young rat condylar cartilage during functional mandibular protraction

OBJECTIVE To investigate the changes in the expression of phospholipase C-gamma1tyr783 (PLC-γ1tyr783) in the condylar cartilage of a young rat during functional mandibular protraction. This work also explores the function of PLC-γ1tyr783 in the rat mandibular condylar cartilage bone remodeling, which could provide experimental evidence for clinical bone ortho- pedic work. METHODS A total of 60 four-week-old male Sprague-Dawley (SD) rats were used in this study. The rats were divided equally and randomly into experimental group and control group. The functional appliances that were fitted to the upper incisors of the animals in the experimental group were worn 24 h a day after the rats were fed for 7 d with homemade pellet feed. The animals in the experimental group, along with their matched controls, were sacrificed after 1, 3, 7, 14, 21, and 28 d. The bilateral condylar was fixed, decalcified, dehyded, and then conventional paraffin embedded. Immunohisto- chemistry of PLC-γ1tyr783 was applied to observe its express distribution and variation. RESULTS The expression of PLC-γ1tyr783 decreased gradually in the control group, which showed age-related changes (P > 0.05). On the 14th day, PLC-γ1tyr783 expres- sion in the experimental group was significantly higher than that in the control group. PLC-γ1tyr783 expression began to appear statistically and significantly different between the two groups (P < 0.01). CONCLUSION PLC-γ1tyr783 is involved in the bone remodeling process of the rat condylar cartilage after functional mandibular-protraction.

Osteoarthritic Changes After Superior and Inferior Joint Space Injection of Hyaluronic Acid for the Treatment of Temporomandibular Joint Osteoarthritis With Anterior Disc Displacement Without Reduction: A Cone-Beam Computed Tomographic Evaluation

This study compared the effect of superior and inferior joint space injections of hyaluronic acid (HA) and evaluated osteoarthritic changes in patients diagnosed with temporomandibular joint (TMJ) anterior disc displacement without reduction (ADDw/oR) in association with osteoarthritis (OA) by cone-beam computed tomography (CBCT). One hundred forty-one patients with research diagnostic criteria for ADDw/oR in association with TMJ OA were randomly assigned to 1 of 2 study groups that received superior or inferior joint space injection of HA. CBCT and clinical examination were performed before treatment and at 3 and 9 months after treatment. One hundred twenty-six patients returned for the 3-month evaluations, and 74 returned for the 9-month evaluations. Condylar remodeling and TMJ function showed improvement in most patients after treatment. At 3 months, remodeling scores in the superior and inferior groups were 2.14 ± 3.16 and 4.08 ± 3.82, respectively, and scores were 4.80 ± 3.36 and 7.47 ± 3.90 at 9 months. There were significant differences between the superior and inferior groups at 3 and 9 months after treatment (3-month, P = .002; 9-month, P = .002). The Helkimo index of the inferior group was significantly lower than that of superior group at 3 and 9 months (3-month, P = .008; 9-month, P = .028). There were no significant differences in maximal mouth opening between the 2 groups at 3 and 9 months (3-month, P = .82; 9-month, P = .20). Superior and inferior joint space injections of HA are effective methods for the treatment of ADDw/oR in association with TMJ OA. The injection of HA within the inferior joint space appears to result in better condylar reparative remodeling and improvement in jaw function.

Clinical evaluation of open and close treatment in pediatric condylar fractures

To evaluate the long-term clinical and radiographic outcomes of open and close treatment of condylar fractures of mandible in children. A total of 78 cases (105 mandibular condylar fractures) were included in this study. All patients (younger than 12 years at the time of injury were followed up for at least 3 years. According to the classification of the condylar fractures, open or close treatment was chosen. Clinical outcomes were classified as favorable or unfavorable depending on the mouth opening, pattern of mouth opening, occlusion, facial symmetry. Condylar remodeling was defined as complete, moderate, or poor based on the radiographic findings. Depending on the classification, 14 sides of type I, 48 sides of type II and 43 sides of type III were included in this study. Open treatment was chosen in 51 sides and close treatment was chosen in 54 sides. Most of the patients acquired satisfactory clinical outcomes. Better radiologic remodeling of the condylar process was found in the patients treated by open treatment. Favorable long-term clinical outcomes were obtained in both open and close treatment of mandibular condylar fractures. A better morphological remodeling of condylar process was found in patients with open treatment.

Effect of post–orthognathic surgery condylar axis changes on condylar morphology as determined by 3-dimensional surface reconstruction

To evaluate the effect of postoperative condylar axis changes on mandibular condylar remodeling by comparing the condylar head in three-dimensional (3D) surface reconstructions before and after surgery in skeletal Class III deformities (one-jaw [mandibular setback] or two-jaw surgery), and also to determine the relationship between condylar inward rotation and condylar surface remodeling after orthognathic surgery. A retrospective analysis was conducted of 30 patients with skeletal Class III deformities who had received orthognathic surgery. Group 1 underwent one-jaw surgery (10 men, five women, age 22.4 ± 3.3 years), and group 2 underwent two-jaw surgery (10 men, five women, age 22.3 ± 2.2 years). Sixty condyles were reconstructed and superimposed pre- and postoperatively to compare the changes of condylar surfaces. The relation between the condylar axis change and the surface change using the Pearson correlation were investigated from the 3D image software. Condylar surface changes before and after the surgery were significant. The postoperative inward rotation of the condyles was correlated with the average absolute deviation of the condyles, regardless of the surgery type (one- or 2-jaw surgery; r = .70, P < .05). After orthognathic surgery, condylar surface changes occurred, and condylar inward rotation was closely related to changes of condylar surface.

Validation of a novel semi-automated method for three-dimensional surface rendering of condyles using cone beam computed tomography data

Morphological changes of the condyles are often observed following orthognathic surgery. In addition to clinical assessment, radiographic evaluation of the condyles is required to distinguish the physiological condylar remodelling from pathological condylar resorption. The low contrast resolution and distortion of greyscale values in cone beam computed tomography (CBCT) scans have impeded an accurate three-dimensional (3D) rendering of the condyles. The current study proposes a novel semi-automated method for 3D rendering of condyles using CBCT datasets, and provides a clinical validation of this method. Ten patients were scanned using a standard CBCT scanning protocol. After defining the volume of interest, a greyscale cut-off value was selected to allow an automatic reconstruction of the condylar outline. The condylar contour was further enhanced manually by two independent observers to correct for the under- and over-contoured voxels. Volumetric measurements and surface distance maps of the condyles were computed. The mean within-observer and between-observer differences in condylar volume were 8.62mm3 and 6.13mm3, respectively. The mean discrepancy between intra- and inter-observer distance maps of the condylar surface was 0.22mm and 0.13mm, respectively. This novel method provides a reproducible tool for the 3D rendering of condyles, allowing longitudinal follow-up and quantitative analysis of condylar changes following orthognathic surgery.

Cone-beam computed tomographic evaluation of the condylar remodeling occurring after mandibular set-back by bilateral sagittal split ramus osteotomy and rigid fixation

ObjectiveTo evaluate condylar head remodeling after mandibular set-back sagittal split ramus osteotomy (SSRO) with rigid fixation in skeletal class III deformities. The correlation between condylar head remodeling and condylar axis changes was determined using cone-beam computed tomography (CBCT) superimposition.MethodsThe CBCT data of 22 subjects (9 men and 13 women) who had undergone mandibular set-back SSRO with rigid fixation were analyzed. Changes in the condylar head measurements and the distribution of the signs of condylar head remodeling were evaluated by CBCT superimposition.ResultsThe subjects showed inward rotation of the axial condylar angle; reduced condylar heights on the sagittal and coronal planes; and resorptive remodeling in the anterior and superior areas on the sagittal plane, superior and lateral areas on the coronal plane, and anterior-middle and anterior-lateral areas on the axial plane (p < 0.05).ConclusionsThe CBCT superimposition method showed condylar head remodeling after mandibular set-back SSRO with rigid fixation. In skeletal class III patients, SSRO with rigid fixation resulted in rotation, diminution, and remodeling of the condylar head. However, these changes did not produce clinical signs or symptoms of temporomandibular disorders.

Condylar remodeling accompanying splint therapy: a cone-beam computerized tomography study of patients with temporomandibular joint disk displacement

The aim of this study was to evaluate osseous changes accompanying anterior repositioning splint (ARS) therapy in patients with temporomandibular joint disk displacement. Cone-beam computerized tomography (CBCT) data of 36 patients with intermittent or permanent closed-lock were used; 23 patients with permanent closed-lock had their displaced disks physically reduced by mandibular manipulation before ARS therapy. CBCT was performed before and ≈ 6 months after ARS therapy. The presence and location of "double contour" images suggesting condylar bone remodeling were statistically analyzed. The "double contour" images after ARS therapy were observed in ≈ 80% of patients, more frequently in joints with signs of displaced disks. The "double contour" appeared more often on the posterior bevel as well as the medial and middle part of condyles (P < .01). ARS therapy can facilitate regenerative remodeling of condyles. CBCT is a useful tool for monitoring osseous changes in condyles.

Condyle and mandibular bone change after unilateral condylar neck fracture in growing rats

Unilateral fracture of the condylar neck in immature subjects might lead to mandible asymmetry and condyle remodelling. A rat model was used to investigate mandibular deviation and condylar remodelling associated with condyle fracture. 72 4-week-old male rats were randomly divided into three groups: an experimental group (unilateral transverse condylar fracture induced surgically), a sham operation group (surgical exposure but no fracture), and a non-operative control group (no operation). The rats were killed at intervals up to 9weeks after surgery, and outcomes were assessed using various measures of mandible deviation, histological and X-ray observation, and immunohistochemical measures of expression levels of connective tissue growth factor (CTGF) and type II collagen (Col II). The fracture led to the degeneration of mandibular size, associated with atrophy of fractured condylar process. Progressive remodelling of cartilage and increasing expression levels of CTGF and Col II were found. The authors conclude that condylar fracture can lead to asymmetries in mandible and condyle remodelling and expression of CTGF and Col II in condylar cartilage on both the ipsilateral and the contralateral sides.

Management of paediatric mandibular condylar fractures with screw-based semi-rigid intermaxillary fixation

This study was designed to evaluate the feasibility and safety of screw-based semi-rigid intermaxillary fixation (IMF) combined with a specially designed occlusal splint in the conservative treatment of paediatric mandibular condylar fractures. Thirteen paediatric patients with 20 sides of condylar fractures treated with semi-rigid IMF were analyzed retrospectively. Semi-rigid IMF was achieved by inserting self-drilling IMF screws into the anterior alveolar bone of the maxilla and mandible suspended with elastic bands. An occlusal splint with a molar fulcrum was used for functional repositioning of the condylar fragment. After 4 weeks, the screws and occlusal splint were removed. During a mean period of 28.6 months’ follow-up, the patients’ maximal mouth opening increased to a mean of 37.69 mm. Clinical and radiological examinations revealed satisfactory results in facial symmetry and condylar remodelling. No clinical symptoms or radiographic evidence showed dental injuries associated with screw insertion. This study suggests that this method might be a safe, easy, and effective management of paediatric condylar fractures.

Long-Term Follow-Up of Mandibular Condylar Fractures in Children

The aim of this prospective study was to evaluate the long-term clinical and radiographic outcomes of nonsurgically treated mandibular condylar fractures in children. This study includes 42 children (23 girls and 19 boys) with 54 mandibular condylar fractures. All patients were younger than 18 years at the time of injury and were followed for at least 2 years (mean follow-up 4 years). Treatment was either observation or intermaxillary fixation (rigid and/or guiding elastics). Clinical outcome was categorized as favorable or unfavorable. Condylar remodeling was defined as complete, moderate, or poor on the basis of radiographic findings. Thirty-one patients (74%) presented with favorable and 11 (26%) with unfavorable clinical long-term outcome. Unilateral fractures showed a statistically significant increase of unfavorable clinical outcomes compared with bilateral fractures (P = .018). The radiologic examinations showed complete remodeling in 47 (87%), moderate remodeling in 5 (9%), and poor remodeling in 2 (4%) of the condylar fractures. One patient developed condylar overgrowth. No statistically significant relationship between clinical and radiologic outcome was found. Thirty-five patients (83%) had no subjective symptoms, and 41 (98%) described normal chewing function at the last follow-up examination. Nonsurgical treatment of mandibular condylar fractures leads to acceptable remodeling of the condylar process, good clinical long-term outcome, and minimal subjective symptoms in most children. Unilateral fractures significantly increase the risk for unfavorable clinical outcome.

Longitudinal study on skeletal changes during and after bionator therapy using metallic implants

To demonstrate the magnitude and direction of skeletal changes in the maxilla and mandible during and after the use of bionator, as well as their rotations. Methods: Partial superimposition on the maxilla and mandible on the metallic implants and total superimposition on the cranial base were performed at three periods, T1 before bionator therapy, T2 after bionator therapy, and T3 5.68 years after T2. Results: There was total clockwise maxillary rotation and counterclockwise mandibular rotation, in the North American technique, throughout the study period, as well as extensive remodeling on the condylar region, especially in vertical direction and on the gonial region in horizontal direction. Conclusions: The total maxillary rotation seemed to be significantly affected by therapy than the mandible. There was a clear change in the direction of condylar remodeling compared to the period of bionator therapy and posterior bionator therapy. Considering the entire study period, it was observed that intra-matrix rotation of the maxilla and mandible masked their total rotation, causing minimum changes in the matrix rotation.

Comparison of Distraction Osteogenesis Versus Costochondral Graft in Reconstruction of Temporomandibular Joint Condylectomy With Disc Preservation

This study compared transport distraction with costochondral graft in the reconstruction of temporomandibular joint (TMJ) with disc preservation. Bilateral condylectomies with disc preservation were conducted in 12 adult goats. Transport distraction of the mandibular ramus was performed on 1 side and costochondral graft on the other side. Jaw movements, TMJ healing, and condylar remodeling were assessed by clinical, radiologic, and histologic examinations. Transport distraction and costochondral graft established a new condyle separating from the preserved disc with a joint space. Both techniques showed no significant difference in ankylosis scores up to 24 weeks. Signs of calcification were not noted in the transport distraction or costochondral graft side. No significant change of maximal jaw movements was found at any time point from 2 to 24 weeks. Distraction osteogenesis is an effective reconstruction method for TMJ reconstruction. No significant difference between these 2 techniques in reconstruction of the TMJ was noted.

Proteomic analysis of early‐response to mechanical stress in neonatal rat mandibular condylar chondrocytes

The objectives of this study were to investigate the early response to mechanical stress in neonatal rat mandibular chondrocytes by proteomic analysis. To evaluate its molecular mechanism, chondrocytes were isolated and cultured in vitro, then loaded mechanical stress by four-point bending system on different patterns. Morphological observation, flow cytometric analysis, and MTT assays indicated that 4,000 microstrain loading for 60 min was an appropriate mechanical stimulus for the following proteome analysis, which produced a transient but obvious inhibitory effect on the cell cycle. Therefore, we took a proteomic approach to identify significantly differential expression proteins in chondrocytes under this mechanical stress. Using 2-DE and MALDI-TOF, we identified seven differentially expressed proteins including the MAPK pathway inhibitor RKIP, cytoskeleton proteins, actin and vimentin, and other selected proteins. Some differentially expressed proteins were validated by both Western blot analysis and fluorescent staining of cytoskeleton at different loading times. The vimentin and RKIP responsive expression were also proven in vivo in oral orthopedic treatment rats, which was in line with the result in vitro. The histological changes in cartilage also showed the inhibition effect. Furthermore, the expressional level of phosphorylated ERK was increased, which demonstrates the changes in MAPK activity. Taken together, these data indicate that mechanical stress resulted in vimentin expression changes first and then led to the subsequent changes in actin expression, MAPK pathway regulated by RKIP and heat shock protein GRP75. All those changes contributed to the cytoskeleton remolding and cell cycle inhibition, finally led to condylar remodeling.

Transport distraction versus costochondral graft for reconstruction of temporomandibular joint ankylosis: which is better?

This study compared the methods of transport distraction and costochondral graft in reconstruction of temporomandibular joint (TMJ) ankylosis. Bilateral bony TMJ ankylosis was induced in 12 adult goats. Transport distraction of the mandibular ramus was performed on one side, whereas costochondral graft was performed on the other side. Jaw movements, TMJ healing, condylar remodeling, and recurrence of ankylosis were assessed by clinical, radiological, and histological examinations. Both transport distraction and costochondral graft established a neo-condyle separating from the pseudo-disc with a joint space. The ankylosis scores were higher in the distraction side in the first 12 weeks. Both techniques showed no significant difference in the calcification scores and recurrence of ankylosis in the long term. The maximal jaw movements in 3 directions returned to the pre-ankylosis stage by both methods. Distraction osteogenesis is an effective reconstruction method for TMJ ankylosis, matching the gold standard of costochondral grafting.