Condylar Remodeling Research Articles

Recent evaluation and analysis of the clinical effect of two closed treatment methods in children with intracapsular condyle fracture

Objective: To summarize and analyze clinical characteristics of pediatric mandibular condylar fractures and the long-term therapeutic effects of closed treatment. Methods: A retrospective study was conducted for pediatric condylar fracture in the Department of Oral and Maxillofacial Surgery of Peking University School and Hospital of Stomatology from October 2015 to October 2019, including 33 males (67.3%) and 16 females (32.7%), with an average age of (8.3±2.1) years old. According to the treatment methods, the children were divided into two groups: group A was a removable occlusal splint accompanied with functional exercise, group B was a pure functional exercise. Forty-nine cases (76 sides) children with intracapsular condylar fracture were included in this study. Twenty-three cases in group A and 26 cases in group B. The maximum month opening increased from (20.0±6.2) mm to (46.0±5.3) mm 6 months after closed treatment. Subjective evaluation, special examination, qualitative analysis and quantitative analysis of imaging were used to evaluate the condylar remodeling and functional recovery of temporomandibular joint in two groups of children after closed treatment of intracapsular condyle fracture. Results: There was no significant difference in subjective evaluation, maximum opening examination, mouth open-type, mandibular protrusion, lateral movement and qualitative analysis of imaging at the six-month follow-up after injury. Quantitative imaging measurements showed that the condylar anteroposterior diameter and condylar height in Group B were significantly higher than those in Group A after 1 year of injury. Conclusions: Closed treatment for pediatric condylar fractures can achieve satisfactory results. After 6 months of injury, the children in the two groups could recover the temporomandibular joint function and promote the condylar adaptative remodeling.

Condylar Remodeling and Skeletal Changes Following Occlusal Splint and Manual Therapy: A Cone Beam Computed Tomography Study in Temporomandibular Disorders.

Background: Temporomandibular disorders (TMD) may be associated with degenerative disease of temporomandibular joint (TMJ), such as condyle erosion and subchondral cysts. Occlusal splint and cranio-mandibular manual therapy, or combined therapy, is recommended as a conservative treatment to alleviate pain-related signs and symptoms in TMD. This study aimed to assess osseous condylar changes and skeletal changes following occlusal splint and cranio-mandibular manual therapy in TMD using cone beam computed tomography (CBCT). Methods: A retrospective cohort study included 24 patients diagnosed with TMD. Combined therapy was performed until pain-related signs and symptoms disappeared. CBCT scans were performed before and after therapy. Osseous structure of condyles and their subsequent modifications were analyzed on CBCT images: flattening, erosion, and subchondral cyst. Sella-Nasion-A point (SNA), Sella-Nasion-B point (SNB), A point-Nasion-B point (ANB), Sella-Articulare-Gonion (Condylar angle), and anterior and posterior facial height (AFH, PFH) were measured on CBCT-generated lateral cephalograms. A paired t-test, Wilcoxon rank-sum test, McNemar test, and Stuart-Maxwell test were used for the statistical analyses. Results: The treatment period with combined therapy was 7.42 ± 3.27 months, and 21 out of 33 TMJ presenting degenerative disease (63.6%) had significant complete remodeling (p < 0.05). Following therapy, SNB significantly decreased from 75.61 ±3.47° to 74.82 ± 3.41° (p = 0.02), ANB significantly increased from 4.05° (3.35-4.9°) to 4.8° (3.3-6.12°) (p < 0.001), AFH significantly increased from 112.85 mm (109.28-118.72) to 115.3 mm (112.58-118.88) (p < 0.001), PFH/AFH significantly decreased from 64.17 (61.39-66.1) to 63 (59.68-64.51) (p = 0.012), and condylar angle significantly increased from 140.84 ± 8.18° to 144.42 ± 8.87° (p = 0.007). Conclusion: Combined therapy promoted significant condylar remodeling in TMJ degenerative disease, along with skeletal changes (mandibular retrusion and increase in facial height). Therapeutic strategies should consider condylar remodeling in TMD. Skeletal and dental parameters should be evaluated prior to occlusal splint therapy.

A study on the precision of voxel- and surface-based mandibular superimposition.

To apply the more accurate technique for mandibular superimposition and provide a valuable reference for the assessment of mandibular tooth movement and condylar remodeling before and after orthodontic treatment. This retrospective study involved 38 adult patients who underwent two cone beam computer tomography (CBCT) scans at different stages of treatment at Fujian Provincial People's Hospital between September, 2020 and December, 2022. The software Dolphin was used for mandible segmentation, enabling voxel-based mandibular superimposition with the mandibular ramus as the reference region. The Geomagic Wrap software was employed to process surface-based mandibular superimposition with the mandibular ramus as a reference. Additionally, the voxel and surface-based methods were compared for precision, with the mandibular ramus being the reference. After voxel-based mandibular superimposition using the mandibular ramus as a reference, with all measurement errors (< 0.20 mm). In contrast, the results of surface-based mandibular superimposition with the same reference, and the measurement errors were all less than 0.10 mm. The Wilcoxon signed-rank test revealed statistically significant differences between AS1 and BS1, AS2 and BS2, AS3 and BS3, and AS4 and BS4 (all r< 0.05). Moreover, the absolute mean distances of AS1-AS4 were all greater than those of BS1-BS4. All mandibular superimposition procedures, including the voxel- and surface-based ones using the mandibular ramus as a reference, have acceptable surface errors (< 0.20 mm), indicating the good reliability of these techniques. Under the specified conditions, surface-based mandibular superimposition appears to yield a higher degree of precision compared with the voxel-based technique.

A New Method in Dealing With Children's Condylar Fracture by Botulinum Toxin A Injection in Lateral Pterygoid Muscle.

Condylar is one of the most vulnerable sites to be traumatized in pediatric mandible fracture, while temporomandibular joint ankylosis might be the most severe complication of condylar fracture in children. There exists a long-time controversy on the treatment of condylar fractures in children. Considering the risk of facial nerve injury and a certain probability of absorption or even ankylosis after open reduction and internal fixation (ORIF) of condylar fractures, a series of nonsurgical approaches are preferred in cases without severe malocclusion or shortening of the ramus. Our treatment plan was carried out through combining procedures of Botulinum toxin A injection in lateral pterygoid muscle with ORIF of para symphyseal fracture; subsequently, a conservative way of the occlusal splint with elastic traction was performed. Three patients of bilateral or unilateral condylar fractures, aged between 2y and 6y, were involved in this treatment. After more than 1 year's follow-up, the occlusion was satisfactory in all patients. Condylar remodeling was approximately complete in 3 months, and no unwanted complications were observed. We may expect this method to offer a new idea when dealing with children's condylar fracture.

The Role of Orthodontics in the Management of Maxillofacial Fractures in Children: A Review on Contemporary Approaches.

Maxillofacial fractures present complex challenges requiring effective orthodontic management to restore function and aesthetics. This review explores various orthodontic techniques, including fixed braces, maxillomandibular fixation (MMF), functional orthodontic therapy (FOT), and acrylic splints, emphasizing their roles in stabilizing fractures and promoting healing. The management of condylar fractures is discussed, highlighting the benefits of early intervention with functional appliances to facilitate condylar remodeling in children and adolescents. Additionally, the review covers splinting methods for dental and dentoalveolar fractures and the use of open reduction internal fixation (ORIF) for maxillary fractures. It addresses the complications and challenges of fracture management, the need for a multidisciplinary approach, and the limitations of current studies. Future directions include the use of advanced technologies such as virtual surgical planning (VSP) and 3D printing to enhance treatment precision and outcomes. This review provides a comprehensive overview of orthodontic strategies for maxillofacial fractures, offering insights into clinical applications and future advancements.

Quantitative Assessment of Condylar Remodeling After Open Reduction and Internal Fixation in Mandibular Condylar Head Fractures.

Open reduction and internal fixation (OR/IF) and closed treatments are viable options, with OR/IF gaining popularity in mandibular condylar head fracture (CHF). Sufficient research is lacking on long-term condylar morphologic changes. This study quantitatively evaluated the morphologic changes in the condylar head in patients who underwent OR/IF for CHF without the removal of osteosynthesis material. A retrospective study analyzed patients who underwent OR/IF for CHF between November 2010 and August 2022. The transverse/lateral condyle width and condyle height were radiologically analyzed using panoramic and reverse Towne view x-ray images at immediate (T0), short-term (T1), and long-term (T2) postoperative periods. The study involved 29 patients with 32 surgically treated CHF. Long-term condyle height decreased significantly from 18.9±0.8mm at T0 to 18.1±0.8mm at T1 (P=0.042), and further to 17.3±0.7mm at T2 (P=0.034). Transverse width slightly reduced from 18.7±0.7mm at T0 to 17.9±0.8mm at T1 (P=0.001) but remained stable from T1 to T2 (17.6±1.0mm, P=0.756). Following surgery, maximal mouth opening averaged 39.5±6.1mm, with one case of chin deviation and three cases of joint pain. The condyle undergoes long-term shortening without altering its width. Nevertheless, patients experience favorable functional outcomes, including satisfactory mouth opening and occlusion. In addition, it is advisable not to remove the osteosynthesis material, as the remaining material causes minimal functional impairment and bone resorption.

TMJ Symptoms Resolve With Orthognathic Surgery and Are Associated With Condylar Remodeling

TMJ Symptoms Resolve With Orthognathic Surgery and Are Associated With Condylar Remodeling

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

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

Mouth breathing induces condylar remodelling and chondrocyte apoptosis via both the extrinsic and mitochondrial pathways in male adolescent rats

The prevalence of mouth breathing is high in children and adolescents. It causes various changes to the respiratory tract and, consequently, craniofacial growth deformities. However, the underlying mechanisms contributing to these effects are obscure. Herein, we aimed to study the effects of mouth breathing on chondrocyte proliferation and death in the condylar cartilage and morphological changes in the mandible and condyle. Additionally, we aimed to elucidate the mechanisms underlying chondrocyte apoptosis and investigate any variations in the related pathways. Subchondral bone resorption and decreased condylar cartilage thickness were observed in mouth-breathing rats; further, mRNA expression levels of Collagen II, Aggrecan, and Sox 9 were lower in the mouth breathing group, while those of matrix metalloproteinase 9 increased. TdT-mediated dUTP nick end labelling staining and immunohistochemistry analyses showed that apoptosis occurred in the proliferative and hypertrophic layers of cartilage in the mouth breathing group. TNF, BAX, cytochrome c, and cleaved-caspase-3 were highly expressed in the condylar cartilage of the mouth-breathing rats. These results suggest that mouth breathing leads to subchondral bone resorption, cartilage layer thinning, and cartilage matrix destruction, inducing chondrocyte apoptosis via both the extrinsic and mitochondrial apoptosis pathways.

Three-dimensional quantitative changes of condyle in patients with skeletal class III malocclusion after bimaxillary orthognathic surgery with 5-year follow-up.

The present study aimed to characterize three-dimensional (3D) long-term quantitative condyle change including positional, surface, and volumetric alterations in patients with skeletal class III malocclusion treated with bimaxillary orthognathic surgery. Twenty-three eligible patients (9 males, 14 females, mean age: 28.28years old) treated from Jan. 2013 to Dec. 2016 with postoperative follow-up over 5years were retrospectively enrolled. Cone-beam computed tomography scan for each patient was conducted at 4 stages: 1week preoperatively (T0), immediately after surgery (T1), 12months postoperatively (T2), and 5-year postoperatively (T3). Positional changes, surface, and volumetric remodeling of condyle were measured in segmented visual 3D models and statistically compared between stages. Our 3D quantitative calibrations revealed that the condylar center shifted in anterior (0.23 ± 1.50mm), medial (0.34 ± 0.99), and superior (1.11 ± 1.10mm) directions and rotated outward (1.58 ± 3.11°), superior (1.83 ± 5.08°), and backward (4.79 ± 13.75°) from T1 to T3. With regard to condylar surface remodeling, bone formation was frequently observed in the anteromedial areas, while bone resorption was commonly detected in the anterolateral area. Moreover, condylar volume remained largely stable with a minimal reduction during the follow-up. Collectively, although condyle undergoes positional changes and bone remodeling after bimaxillary surgery in patients with mandibular prognathism, these changes largely fall in the range of physical adaptations in the long run. These findings advance the current understanding of long-term condylar remodeling after bimaxillary orthognathic surgery in skeletal class III patients.

Investigating the relationship between the remodeling of TMJ bony structures and condylar rest position following orthognathic surgery in class II and class III skeletal malocclusions

ObjectivesWe investigated the bone remodeling in the condyle and glenoid fossa after surgically corrected class II and class III dentoskeletal malocclusion patients and the relationship between these changes and the condylar rest position. MethodsA retrospective study was conducted based on the pre-operative and 1-year postoperative computed tomography (CT) scans of class II and class III skeletal malocclusion patients. Condylar remodeling was assessed by total volume change and surface distance between corresponding points in the regions of interest (ROI). Glenoid fossa remodeling was measured by the surface distance between the closest points in the ROI. The association between the remodeling of TMJ bony structures and the condylar position was tested by Spearman’s correlation. ResultsTwenty-one subjects with class II (17 females, 4 males) and twenty subjects with class III (13 females, 7 males) were recruited.The condylar volumes significantly decreased after surgery in class II malocclusion patients and significantly increased in class III malocclusion patients (p < 0.01). The condyle and glenoid fossa experienced remodeling of less than 1.5 mm and 1 mm respectively. Positional change of condyle at the jaw rest position had a weak correlation with condylar remodeling (p < 0.05, 0.2 ≤ |r| ≤0.4), but no association with the glenoid fossa remodeling (p > 0.05). ConclusionsThe volume of condyles changed significantly after orthognathic surgery in both groups. Both condyle and glenoid fossa experienced remodeling in class II and Class III patients. Those changes did not considerably influence the change of the condylar rest position.

Effects of food hardness on temporomandibular joint osteoarthritis: Qualitative and quantitative micro-CT analysis of rats in vivo

BackgroundTemporomandibular joint osteoarthritis (TMJ-OA) is a degenerative joint disease in which quantitative analysis based on magnetic resonance image (MRI) or cone-beam computed tomography (CBCT) remains limited. Moreover, the long-term effects of soft food on the adaptive condylar remodeling process in TMJ-OA remain unclear. This study aimed to assess the effects of food hardness on adaptive condylar remodeling in a healthy TMJ, TMJ-OA, and controlled TMJ-OA. MethodsComplete Freund’s adjuvant (CFA) was used for TMJ-OA induction and Link-N (LN) for TMJ repair. Eighteen mature rats were randomly divided into six groups: (1) control/normal diet (Ctrl-N); (2) control/soft diet (Ctrl-S); (3) TMJ-OA/normal diet (CFA-N); (4) TMJ-OA/soft diet (CFA-S); (5) Link-N-controlled TMJ-OA/normal diet (LN-N); and (6) Link-N-controlled TMJ-OA/soft diet (LN-S). Micro-CT was performed 14, 21, and 28 days after CFA injection to analyze the bone volume, bone volume fraction (BVF), bone mineral density (BMD), and trabecular bone number and thickness (Tb.N, Tb.Th). MRI and histological imaging were performed to support the analysis. ResultsUnder CFA treatment, the BVF and BMD decreased significantly (p < 0.01) and later recovered to normal. However, more significant improvements occurred in normal-diet groups than soft-diet groups. Additionally, bone volume changes were more predictable in the normal-diet groups than in the soft-diet groups. The normal-diet groups presented a significant decrease and increase in the Tb.N and Tb.Th, respectively (p < 0.05), while the Tb.N and Tb.Th in the soft-diet groups remained largely unchanged. Furthermore, a significantly higher frequency of irregularities on the condylar articular surface was found in the soft-diet groups. ConclusionsCompared with a soft diet, a normal diet may be beneficial for preserving condyle articular surface and directing bone remodeling in TMJ-OA rats.

Changes in the condylar head after orthognathic surgery in Class III patients: a retrospective three-dimensional study.

To evaluate the axial and dimensional changes of the condylar head after orthognathic surgery, including Le Fort I and bilateral sagittal split ramus osteotomies, and to assess condylar remodeling through three-dimensional (3D) surface superimposition. Twenty-four patients (15 females, 9 males; mean age: 32.22 ± 6.92 years) with skeletal Class III deformity were included in the study. Cone-beam computed tomography data obtained in the preoperative (T0) and postoperative (T1) periods were examined using Mimics and 3-Matic software. The height, depth, and width of the condylar head and its angular changes were measured. The volumes of the 3D reconstructed models were calculated, and remodeling amounts were evaluated through regional surface superimposition. Statistical significance was set at P < .05. Following the surgery, there was a significant decrease in the size of condyles (P < .05). An inward rotation of the condyles was found in the axial plane (T0: 79.60 ± 6.01°, T1: 76.6 ± 6.48°, P < .05). The maximum resorption, maximum apposition, mean remodeling, and mean absolute remodeling were -2.63 ± 1.23 mm, 1.15 ± 0.4 mm, -0.30 ± 0.34 mm, and 0.73 ± 0.43 mm, respectively. No correlation was found between the angular changes and remodeling parameters or linear and volumetric changes of the condylar head (P > .05). Condyles undergo a remodeling process with a resorptive character following orthognathic surgery, without clinically significant effects in the present study.

Condylar morphology and position changes after miniscrew-assisted rapid palatal expansion in skeletal Class III malocclusion adult patients with mandibular deviation and unilateral posterior crossbite

BackgroundTo evaluate the morphological and positional changes of mandibular condyle after miniscrew-assisted rapid palatal expansion (MARPE) in skeletal Class III malocclusion adult patients with horizontal mandibular deviation (MD).MethodsThe sample consisted of 15 patients with MD (6 males and 9 females, mean age 21.58 ± 3.12 years). The CBCT scans were taken before and after MARPE immediately. The pre- and post-registered images of the cranial base and mandible were measured, respectively, by Mimics.ResultsAfter expansion, the distance between superior condylar point and the Frankfort horizontal plane on the deviated side and the non-deviated side increased by 0.96 ± 0.60 mm (P = 0.011) and 0.70 ± 0.65 mm (P = 0.046); coronal condylar angle of the deviated side increased by 0.39° ± 0.34 (P = 0.028) and 0.06° ± 0.49 (P = 0.917) on the non-deviated side. No statistically significant differences were found when comparing the condylar position on both sides before and after treatment. The degree of mandibular deviation decreased 0.43 mm (P = 0.270).ConclusionsThis study suggested that for skeletal Class III malocclusion adult patients with horizontal MD, the condyle on the deviated side rotated toward the non-deviated side in the coronal direction; the condylar remodeling occurred mainly on the deviated side after MARPE in the vertical direction.

Decellularized small intestine submucosa device for temporomandibular joint meniscus repair: Acute timepoint safety study.

Temporomandibular joint (TMJ) Meniscus removal is an option for the patient to regain full range of motion if the disc is irreversibly damaged or unable to be reduced. However, this procedure leaves the joint vulnerable to condylar remodeling and degeneration. We have shown that extracellular matrix (ECM) scaffolds remodel into a tissue with near native TMJ meniscus in previous studies. The next step towards clinical translation is to manufacture the ECM scaffold as a device under good manufacturing practices (GMP) and test it in a pre-clinical animal study under good laboratory practices (GLP). The primary objective of this study was to evaluate the in-vivo histopathological response to a Prototype GMP manufactured device made of decellularized porcine small intestinal submucosa (SIS), by observing for signs of surrounding tissue reaction to the device that are indicative of an adverse host response in comparison to an empty control at 21 days post-surgical implantation in a canine TMJ meniscus removal and implant model in a GLP setting. The conclusive findings were that the ECM device is safe for placement in the TMJ. After 21 days post implantation, histology of tissue surrounding the device and draining lymph nodes showed that the Prototype GMP device had no negative effects compared to the empty site (as evaluated by the board-certified veterinary pathologist). Furthermore, there was a lack of negative findings for clinical pathology (hematology and clinical chemistry), mortality, and body weight/weight change. Future studies will go to one year after implantation to show that the remodel device remains as a viable tissue with near native mechanical properties.

Long-term three-dimensional condylar remodeling during presurgical orthodontics and after orthognathic surgery of mandibular retrognathia with high mandibular plane angle.

Patients with high mandibular plane facial morphology are the most dominant facial type who experience TMJ abnormalities with resultant condylar resorption, affecting the orthodontic and orthognathic treatment outcomes. The study aimed to quantitatively assess the three-dimensional condylar remodeling during the presurgical orthodontics and after orthognathic surgery of the retrognathic mandible with a high mandibular plane angle. The study also investigated the correlation between the resultant remodeling based on the hypothesis that condylar resorption following orthognathic surgery is a part of a progressive presurgical resorption process. The study included adults with mandibular retrognathism and high mandibular plane angle who have computed tomography scans (CT) obtained before any treatment (T0), after completion of presurgical treatment before surgery (T1), and at long-term follow-up after surgery (T2). DICOM of CT scan was gathered and processed using ITK-SNAP and 3D Slicer software. The interval between T0 and T1 was represented as a presurgical phase, while between T1 and T2 was defined as a postsurgical phase (T1-T2). Twenty-five patients (50 condyles) were included with a mean age of 23 ± 3.2years. The mean of the follow-up during the presurgical phase was 19.8 ± 7.1months and 15.5 ± 5.5months during the postsurgical phase. The condylar volume during the presurgical phase (T0-T1) was relatively stable (- 3.3 ± 37.2mm3). However, during the postsurgical phase (T1-T2), the volume was significantly reduced - 113.8 ± 98.3mm3 (P < 0.001). Localized condylar surface resorption during the postsurgical phase was significantly higher than during the presurgical phase (P < 0.05). No correlation was found between the localized condylar surface remodeling during the presurgical and postsurgical phases. However, a negative statistically significant correlation existed between the overall condylar volume changes during the presurgical and postsurgical phases (r = 0.502, P < 0.001). Significant condylar resorption following orthognathic surgery of the retrognathic mandible with a high mandibular plane angle might occur regardless of the presurgical status of the condyle. The study provided anevidence to be discussed with the patients and considered throughout the treatment of mandibular retrognathia with high mandibular plane angle.

Natural course of severe temporomandibular joint osteoarthrosis evaluated by a novel condylar remodelling scoring system and quantitative volumetric analysis

Temporomandibular joint osteoarthrosis (TMJ-OA) frequently causes mild, moderate, or severe condylar morphological changes. A novel condylar remodelling scoring system (CRSS) based on three-dimensional cone beam computed tomography images is proposed, which is used to grade condylar morphological changes. In the CRSS, the condyle is divided into 10 regions by 11 reference points. For each increase in the number of regions involved in TMJ-OA, one point is subtracted from the full score of 10. The intra-class correlation coefficients for intra- and inter-observer agreement (range 0.656–0.898 and 0.841–0.906, respectively) indicated that the CRSS had good reliability. Cephalometric analysis showed that the condyles with severe morphological changes were prone to present with a retrognathic and clockwise rotating mandible, shorter ramus height, reduced mandibular length, larger mandibular angle, and maxillary retrusion. Qualitative CRSS evaluation and quantitative volumetric analysis were performed to evaluate the stability of severe TMJ-OA in its natural course (343 condyles). The continuous cortex group showed no remarkable changes with an average follow-up of 2 years. In the discontinuous cortex group, most (74.4%) converted into a continuous cortex during follow-up (mean 2 years).

Three-Dimensional Quantitative Assessment of Condylar Displacement and Adaptive Remodeling in Asymmetrical Mandibular Prognathism Patients After Sagittal Split Ramus Osteotomy.

This study was performed to evaluate the condylar displacement and associated condylar remodeling in class III patients following mandibular setback surgery via sagittal split ramus osteotomy (SSRO). The sample comprised of 26 condyles of 13 subjects (mean age of 21.2±2.6y). We evaluated patients with mandibular prognathism and facial asymmetry who had undergone SSRO for mandibular setback at Korea University Hospital between January 2016 and December 2018. Three-dimensional segmentation of the mandibular condyles was done using the initial cone-beam computed tomography scan and scan taken 12 months postoperatively or later. Quantitative assessments of the 3-dimensional condylar displacement from T0 to T1 and bony remodeling of 8 regions of the condylar head were performed. The correlation between the condylar displacement and condylar head remodeling on the deviated (D) and nondeviated (ND) sides was analyzed. Significant correlations between condylar displacement and surface remodeling were observed in both D and ND condyles. The anteroposterior condylar displacement was significantly different between the D and ND sides (P=0.007). There was no significant difference in condylar remodeling between the 2 sides. Condylar displacement and adaptive remodeling after SSRO varied greatly among individuals. Compared with displacement in the ND condyle, displacement in the D condyle has a greater association with condylar remodeling in both D and ND condyles. There is no significant difference in condylar head remodeling between D and ND condyles.

Inductive Remodeling of Extracellular Matrix Scaffolds in the Temporomandibular Joint of Pigs.

The temporomandibular joint (TMJ) disc is a fibrocartilaginous tissue located between the condyle of the mandible and glenoid fossa and articular eminence of the temporal bone. Damage or derangement of the TMJ disc can require surgical removal (discectomy) to restore function. Removal of the TMJ disc, however, leaves the joint space vulnerable to condylar remodeling and degradation, potentially leading to long-term complications. No consistently effective clinical option exists for repair or replacement of the disc following discectomy. This study investigates the use of an acellular scaffold composed of extracellular matrix (ECM) derived from small intestinal submucosa (SIS) as a regenerative template for the TMJ disc in a porcine model. Acellular SIS ECM scaffolds were implanted following discectomy and allowed to remodel for 2, 4, 12, and 24 weeks postimplantation. Remodeling of the implanted device was assessed by longitudinal magnetic resonance imaging (MRI) over the course of 6 months, as well as gross morphologic, histologic, biochemical, and biomechanical analysis (tension and compression) of explanted tissues (disc and condyle) at the time of sacrifice. When the scaffold remained in the joint space, longitudinal MRI demonstrated that the scaffolds promoted new tissue formation within the joint space throughout the study period. The scaffolds were rapidly populated with host-derived cells and remodeled with formation of new, dense, aligned fibrocartilage resembling native tissue as early as 1 month postimplantation. De-novo formation of peripheral muscular and tendinous attachments resembling those in native tissue was also observed. The remodeled scaffolds approached native disc biochemical composition and compressive modulus, and possessed 50% of the tensile modulus within 3 months postimplantation. No degradation of the condylar surface was observed. These results suggest that this acellular bioscaffold fills a medical need for which there is currently no effective treatment and may represent a clinically relevant "off-the-shelf" implant for reconstruction of the TMJ disc.

Condylar resorption following mandibular advancement or bimaxillary osteotomies: A systematic review of systematic reviews

Several systematic reviews have been published on the effects of mandibular surgery on condylar remodeling without reaching a consensus. The purpose of this systematic review of systematic reviews was to assess the impact of mandibular advancement or bimaxillary surgeries on condylar resorption.A literature search, using several electronic databases, was carried out by two reviewers independently. Article preselection was based on titles and abstracts, and final article selection based on full-text analysis of preselected studies. After final study selection, the quality of studies was assessed using the AMSTAR 2 tool. A decision algorithm was subsequently established to choose the best body of evidence.From an initial yield of 1′848 articles, 23 systematic reviews were identified for further analysis, with ten studies being included in the final selection. Despite the generally low quality of the reviews, certain associations could be made: young patients, female patients, and those with a high mandibular plane angle are more prone to condylar resorption following mandibular advancement osteotomies, especially if anterior rotation of the mandible is performed during surgery. Patients undergoing bimaxillary surgery also appear to have a higher risk of developing condylar resorption.In conclusion, these results confirm the multi-factorial nature of condylar resorption, stressing the need for well-controlled prospective studies with long-term follow-up to clearly identify potential risk factors associated with orthognathic surgery.