Acquired Abnormalities of the Temporomandibular Joint

Pediatric Temporomandibular Joint Pathology

Pediatric temporomandibular joint (TMJ) disorders represent a broad range of congenital and acquired diagnoses. Dentofacial deformities, including facial asymmetry, retrognathism, and malocclusion, commonly develop. Compared with adult TMJ conditions, pain and articular disc pathology are less common. Accurate diagnosis is paramount in planning and prognostication. Several specific considerations apply in preparation for skeletal correction, including timing in relation to disease progression and growth trajectory, expectation for postcorrection stability, reconstructive technique as it applies to expected durability and need for future revision, management of occlusion, and need for ancillary procedures to optimize correction. This article reviews common conditions and treatment considerations.

Accuracy of skeletal scintigraphy for the evaluation of mandibular growth disorders: a systematic review

Bone scans, reflecting blood flow and metabolic activity in a region of interest, are frequently used to evaluate mandibular growth disorders. Increased uptake is a non-specific finding and can occur as a result of multiple causes. The correlation between radioactive tracer uptake and growth activity has not been consistently demonstrated. The aim of this study was to assess the accuracy of planar skeletal scintigraphy (SS), single-photon emission computed tomography (SPECT), and SPECT with computed tomography (CT) images (SPECT/CT) in detecting abnormal mandibular growth activity compared to clinical and radiographic/tomographic methods (reference standard) and histologic findings. A systematic review was conducted following the PRISMA guidelines. Sensitivity, specificity, and accuracy were calculated for planar SS, SPECT, and SPECT/CT. Compared to the reference standard, SPECT/CT had the best diagnostic accuracy (76.5% sensitivity, 90.4% specificity, 83.2% accuracy), followed by planar SS (81.8% sensitivity, 84.5% specificity, 83.0% accuracy) and SPECT (77.7% sensitivity, 72.4% specificity, 74.5% accuracy). The results of this study indicate that SPECT/CT has the best clinical correlation, but the certainty of the evidence is low. The differences in sensitivity and specificity between the three index tests were not clinically significant. The three tests can be useful, with only a small difference in their diagnostic value. Histopathology was found not to be satisfactory as a reference standard.

Imaging Evaluation of the Temporomandibular Joint

This article describes the anatomy and function of the temporomandibular joint (TMJ), provides an overview of the various imaging modalities available for evaluating the TMJ, and discusses a variety of miscellaneous diseases that affect the TMJ.

Mandibular condyle volumes are associated with facial asymmetry in patients with cleft lip and palate: A retrospective cohort study

This study compares condylar volumetric asymmetry and facial asymmetry in patients with cleft lip and/or palate (CLP) and controls. The mandibular condyle is important to facial growth, but its role in facial asymmetry for those with CLP has not been described. Condylar volumes and mandibular asymmetry were retrospectively calculated using Mimics Version 23.0 (Materialise, Leuven, Belgium) from patients with CLP undergoing computed tomography (CT) imaging and a cohort of controls. A total of 101 participants, 60 with CLP and 41 controls, had mean condylar volumetric asymmetry of 16.4 ± 17.4 % (CLP) and 6.0 ± 4.0 % (controls) (p = 0.0002). Patients with CLP who had clinically significant chin deviation (>4 mm) had more asymmetric condyles than those without significant chin deviation (p = 0.003). The chin deviated toward the smaller condyle in patients with facial asymmetry more often than in patients without facial asymmetry (81 % vs. 62 %, p = 0.033). While controls had some degree of condylar asymmetry, it tended to be milder and not associated with facial asymmetry. There is a greater degree of condylar volumetric asymmetry in patients with CLP compared to individuals in the general population. Clinically significant facial asymmetry in CLP is associated with a higher degree of condylar asymmetry, with the facial midline deviating toward the smaller condyle.

A Comparison of the Condyle and Articular Eminence in Asian Juvenile Idiopathic Osteoarthritis Patients with Unilateral and Bilateral TMJ Involvement: A Retrospective Case-Control Study

This study compared the condylar volume, length, and articular eminence (AE) characteristics of normal individuals to those with unilateral and bilateral juvenile idiopathic osteoarthritis (JOA). The 116 patients were divided into four groups: Control (n = 16), affected condyle of unilateral JOA (Aff-Uni) (n = 36), non-affected condyle of JOA (NonAff-uni) (n = 36), and bilateral JOA (Bilateral) (n = 28). The differences in condyle volume and length and AE were analyzed using ANOVA and Bonferroni post-hoc tests. The results showed that Bilateral had a significantly different condylar volume, especially in the condylar head (p < 0.01), specifically the middle, anterior, and medial parts (p < 0.05). Condylar length also differed among the groups, with differences observed between the control group and the other three groups, as well as between the bilateral group and the other three groups (p < 0.01). AE total volume differed between the control group and Aff-Uni. In the detailed comparison, Aff-Uni and NonAff-Uni were smaller than the control group in the posterior, lateral, and medial sections (p < 0.05). In conclusion, depending on the involvement of unilateral or bilateral JOA, there were differences in condylar volume and AE when compared to the normal control group. Therefore, a prognosis should be evaluated by distinguishing between patients with unilateral and bilateral JOA.

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.

Does MRI Distinguish Juvenile Idiopathic Arthritis from Other Causes of Progressive TMJ Destruction?

PURPOSE

Similarities in initial presentations of temporomandibular joint (TMJ) involvement from juvenile idiopathic arthritis (JIA), idiopathic condylar resorption, and other forms of progressive TMJ destruction in children create diagnostic confusion. Treatment pathways, however, depend on determination of etiology. The purpose of this study was to compare TMJ magnetic resonance images (MRIs) of patients with joint degeneration localized to the TMJs to those with JIA and TMJ involvement.

METHODS

This is a retrospective cross-sectional study including subjects younger than 18 years that presented from February 2008 to October 2019 with clinical TMJ degeneration, a gadolinium-enhanced TMJ MRI and a negative pediatric rheumatologic workup ("non-JIA" group), and a series of age and sex-matched subjects with TMJ degeneration on gadolinium-enhanced MRI and JIA ("JIA group"). MRIs were evaluated in a blinded fashion by 1 pediatric radiologist. The primary outcome variable was the radiologist's accuracy in predicting study grouping, assessed in 1 randomly-selected joint per patient. Secondary outcome variables included MRI characteristics of inflammation, osseous damage and articular disc morphology. Independent samples t-tests, sensitivity/specificity, Fisher's exact and Mann-Whitney tests were computed as applicable, and P < .05 was considered significant.

RESULTS

The sample included 34 subjects: 16 non-JIA (75% female, age 13.9 ± 2.8 years) and 18 JIA (77% female, age 13.6 ± 2.8 years) (P ≥ .738). The radiologist correctly classified 64.7% of subjects as non-JIA or JIA (P = .078, sensitivity = 94.4%, specificity = 31.3%). Inflammatory and osseous findings were similar between groups (P ≥ .073). The disc was anteriorly displaced in 9 non-JIA and 0 JIA joints (P < .001, sensitivity = 100%, specificity = 100%) and flattened in 3 non-JIA and 14 JIA joints (P = .006, sensitivity = 38.9%, specificity = 90.6%).

CONCLUSION

Inflammatory and osseous findings on gadolinium-enhanced TMJ MRIs are insufficient to determine the etiology of progressive TMJ destruction. Disc characteristics, however, significantly differ between JIA and non-JIA etiologies and may be important in differentiating these conditions.

Evaluation of effect of single vector mandibular distraction for correction of postankylotic mandibular hypoplasia requiring multiplanar correction: A prospective case series

Introduction

Uniplanar devices have been criticized for being insufficient to correct complex mandibular deformities and associated problems of open bite and cross bite. The use of oblique vector to correct complex multiplanar deformities using uniplanar mandibular distraction devices is the uniqueness of the present case series.

Aim and Objective

The aim of the present case series is to describe the successful use of uniplanar mandibular distraction devices for the correction of complex multiplanar deformities.

Material and Method

The technique of callous molding was employed to overcome any open bite. A total of 40 mandibular distractors in 20 patients (mean age 13 ± 2.67 years) were placed on the mandible for correction of the facial deformity associated with the lower jaw(mandible) in vertical, horizontal and/or sagittal plane, secondary to temporomandibular joint ankylosis. The distraction was done before and after the gap arthroplasty in 15 and 5 patients, respectively. A latency period of 3-5 days was applied, and distraction was performed at a rate of 1 mm/day with the rhythm of 0.5 mm twice daily.

Results

The significant lengthening was observed in both mandibular height (Ar Go) (50.40 ± 1.52 mm from 38.80 ± 4.38mm, P = 0.006) as well as in mandibular corpus length (Go Pg) (79.40 ± 2.28 from 58.80 ± 4.09, P = 0.001). Statistically significant changes in mandibular dimensions, facial proportions, and soft tissue profile were seen, which was assessed with the help of COGS analysis done on lateral cephalogram taken preoperatively and postoperatively.

Conclusion

With intelligent vector planning and callus molding multiplanar complex deformities can be corrected by using semiburieduniplanar devices.

Traumatic temporomandibular joint bony ankylosis in growing rats

BACKGROUND

The pathogenesis of traumatic temporomandibular joint (TMJ) bony ankylosis remains unknown. This study aimed to explore the pathogenesis of traumatic TMJ bony ankylosis in a rat model.

METHODS

Twenty-four 3-week-old male Sprague-Dawley rats were used in this study. Excision of the whole disc, the fibrocartilage damage of the condyle and glenoid fossa, and narrowed joint space were performed in the left TMJ of the operation group to induce TMJ bony ankylosis (experimental side). The right TMJ underwent a sham operation (sham side). The control group did not undergo any operations. At 1, 4, and 8 weeks postoperatively, rats of the operation group were sacrificed and TMJ complexes were evaluated by gross observation, Micro-CT, histological examinations, and immunofluorescence microscopy. Total RNA of TMJ complexes in the operation group were analyzed using RNA-seq.

RESULTS

Gross observations revealed TMJ bony ankylosis on the experimental side. Micro-CT analysis demonstrated that compared to the sham side, the experimental side showed a larger volume of growth, and a considerable calcified bone callus formation in the narrowed joint space and on the rougher articular surfaces. Histological examinations indicated that endochondral ossification was observed on the experimental side, but not on the sham side. RNA-seq analysis and immunofluorescence revealed that Matrix metallopeptidase 13 (MMP13) and Runt-related transcription factor 2 (RUNX2) genes of endochondral ossification were significantly more downregulated on the experimental side than on the sham side. The primary pathways related to endochondral ossification were Parathyroid hormone synthesis, secretion and action, Relaxin signaling pathway, and IL-17 signaling pathway.

CONCLUSIONS

The present study provided an innovative and reliable rat model of TMJ bony ankylosis by compound trauma and narrowed joint space. Furthermore, we demonstrated the downregulation of MMP13 and RUNX2 in the process of endochondral ossification in TMJ bony ankylosis.

Evaluation of Cortical Bone Formation on Mandibular Condyle in Asymptomatic Adolescents and Young Adults Using Cone-Beam Computed Tomography

The aim of this study was to evaluate cortical bone formation on the mandibular condyle using cone-beam computed tomography (CBCT) in asymptomatic adolescents and young adults and to evaluate the relationship between age and sex. CBCT images that can evaluate the shape of the mandibular condyle were selected from asymptomatic patients aged 13−25. The degree of cortication on the mandibular condyle (CMC) was evaluated using CBCT images reconstructed in the axial, sagittal, and coronal planes. CBCT data of 829 patients (413 males, 416 females) were selected and then the left and right images of all patients were acquired; consequently, a total of 1658 temporomandibular joint-related images were evaluated in this study. The degree of CMC was correlated with age in men and women (p < 0.05). The frequency of CMC 0 disappeared in woman aged 20 years and in men aged 21 years. Cortical bone formation of the mandibular condyle was completed at age 22 years in women and 24 years in men. The degrees of cortical bone formation of the mandibular condyle between men and women showed significant differences between the ages of 15−19 and 22 years. This difference can be interpreted as a different mandible growth period between the sexes.

Orthodontic-surgical treatment of an Angle Class II malocclusion patient with mandibular hypoplasia and missing maxillary first molars: A case report

BACKGROUND

Adult patients presenting with Angle Class II division 1 malocclusions that have a strong skeletal etiology can be challenging for clinicians, particularly if accompanied by retrognathia of the mandible and a dolichofacial growth pattern.

CASE SUMMARY

In this case report, we describe the successful orthodontic and surgical management of a 20-year-old woman with an Angle Class II malocclusion with a severe anteroposterior skeletal discrepancy characterized by mandibular deficiency. She had incompetent lips, dental and skeletal Class II malocclusion, high mandibular plane angle, mild mandibular crowding, and two missing maxillary first molars. The treatment plan comprised: (1) Extraction of two mandibular second premolars to decompensate and retract mandibular incisors; (2) pre-surgical alignment, leveling, and space closure of the teeth in both arches, and protraction of the second maxillary molars to close the maxillary space; (3) surgical treatment including a LeFort I osteotomy for maxillary retraction and rotation, a bilateral sagittal split osteotomy for mandibular advancement and rotation, and a genioplasty for correctting the skeletal deformities; and (4) post-surgical correction of the malocclusion.

CONCLUSION

The patient’s facial esthetics was significantly improved and a desirable occlusion was achieved after 16 mo treatment. Follow-up records after 2 years showed stable esthetics and function.

Three-Dimensional Distance Mapping Method to Evaluate Mandibular Symmetry and Morphology of Adults with Unilateral Premolar Scissors Bite

(1) Objective: This study aimed to evaluate the association between unilateral premolar scissors bite and mandibular symmetry of adults via the 3D distance mapping method. (2) Methods: A total of 53 cone-beam computed tomography (CBCT) images of adults with unilateral premolar scissors bite were set as study samples. A total of 53 age- and sex-matched samples without scissors bite were in the control group. Three-dimensional mandibular models and seven mandibular functional units, including condylar process (Co), coronoid process (Cr), mandibular ramus (Ra), mandibular angle (Ma), alveolar process (Ap), mandibular body (Mb), and chin process (Ch) were constructed and mirrored. After superimposition of the original and the mirrored models, 3D distance maps and deviation analysis were performed to evaluate the mandibular symmetry and morphology. (3) Results: In the study group, the matching percentages of the entire mandible (50.79 ± 10.38%), Ap (67.00 ± 12.68%), Mb (66.62 ± 9.44%), Ra (62.52 ± 11.00%), Ch (80.75 ± 9.86%), and Co (62.78 ± 13.56) were lower than that of the entire mandible (58.60 ± 5.52) (p < 0.01), Ap (73.83 ± 8.88%) (p < 0.01), Mb (72.37 ± 8.69%) (p < 0.01), Ra (68.60 ± 7.56%) (p < 0.01), Ch (85.23 ± 6.80%) (p < 0.01), and Co (67.58 ± 10.32%) (p < 0.05) in the control group. However, Cr and Ma showed no significant difference (p > 0.05). (4) Conclusions: The 3D distance mapping method provided a qualitative and quantitative mandibular symmetry and morphology assessment. Mandibular asymmetry was found in adults with unilateral premolar scissors bites. Mandibular functional units, including the alveolar process, mandibular body, mandibular ramus, chin process, and condylar process, showed significant differences, while no significant difference was observed in the coronoid process and mandibular angle.

Correlations Between Mandible Condylar Structures and External Ear Deformities in Hemifacial Microsomia With Three-Dimensional Analysis

ABSTRACT

This study aimed to explore correlations between mandible and ear deformities and quantitative volumetric relations between condylar structures and external ear in hemifacial microsomia. The authors reconstructed three-dimensional craniofacial models from 212 patients with unilateral hemifacial microsomia (the unaffected side as the controls). Patients were evaluated by Pruzansky-Kaban and Marx classification, and divided into 3 age groups (0-6, 7-12, and >12 years old). The mandible condylar structures, including condyle and the condylar skeletal unit, were selected (except the classification of the mandibular or ear deformities (M3)). Along with the external ear (except the classification of the mandibular or ear deformities (E4)), their volumes were measured and analyzed. Spearman correlation coefficient analysis was applied. There was a positive correlation between the mandible and ear deformities (r = 0.301, P < 0.001). Either between the condyle and external ear (P = 0.071-0.493) or between the condylar unit and external ear (P = 0.080-0.488), there were no volumetric relations on the affected side, whereas on the unaffected side were (r = 0.492-0.929 for condyle, r = 0.443-0.929 for the condylar unit, P < 0.05). In most cases, the condylar structures of the classification of the mandibular or ear deformities (M2b) were significantly smaller than the classification of the mandibular or ear deformities (M2a). Results suggested deformities of mandibular condylar structures and ear did not correlate, although deformities of mandible and ear did. The condylar deformity might develop independently from microtia and be more severe within relatively more abnormal temporomandibular joints.

Acquired Facial, Maxillofacial, and Oral Asymmetries—A Review Highlighting Diagnosis and Management

Facial asymmetry refers to the absence of, or the deviation from the regular mirror image of facial structures, relative to a referenced midline axis. It can be attributed to a wide spectrum of deformities, including congenital, developmental, or acquired conditions, which can originate either prenatally or postnatally. Though highly prevalent, asymmetry commonly goes undiagnosed due to its subtle or relative nature. Among the spectrum of conditions, acquired cases are triggered postnatally, in previously normal individuals, thus subjecting them to sudden, eventful psychological and psychosocial disharmony. When detected early, timely management may help intervene progressive growth of these conditions. This, therefore, emphasizes the need for a thorough diagnostic workup including medical/dental history, clinical examinations, study models, photographic and radiographic records for a case-by-case basis to prevent severe functional and aesthetic complications. Recently, advanced diagnostic procedures, such as stereophotogrammetry, 3D stereolithographic models, skeletal scintigraphy (radionucleotide scans), 3D computed tomographic scans, cone-beam computed tomography, and magnetic resonance imaging, have provided innovative diagnostic instruments for numerous craniofacial defects. This descriptive review aims at focusing on the factors leading to frequently encountered conditions of acquired facial asymmetry and highlights their clinical evaluation, conservative and surgical interventions by a multi-disciplinary team of clinicians.

Dental and maxillomandibular incidental findings in panoramic radiography among individuals with mucopolysaccharidosis: a cross-sectional study

Mucopolysaccharidosis (MPS) is a group of rare and inherited metabolic disorders caused by the accumulation of macromolecule glycosaminoglycans inside lysosomes. Affected individuals may have dental and craniofacial tissue alterations, facilitating the development of several oral diseases.

OBJECTIVES

To assess, with panoramic radiographic images, the frequency of dental and maxillomandibular incidental findings among MPS individuals and compare them with non-MPS individuals.

METHODOLOGY

A cross-sectional study evaluating a sample of 14 MPS individuals and 28 non-MPS individuals aged from 5 to 26 years was carried out. They were matched for sex and age on a 2:1 proportion. Panoramic radiographs were assessed for the presence/absence of the following dental and maxillomandibular alterations: dental anomalies of number (hypodontia/dental agenesis, supernumerary teeth); anomalies of form (microdontia, macrodontia, conoid teeth, taurodontism, and root dilaceration); anomalies of position (impacted tooth, inverted tooth, tooth migration, partially bony teeth, complete bony teeth); periapical alterations (furcation lesion, circumscribed bone rarefaction); other alterations (radiolucent bone lesions, radiopaque bone lesions, radiopacity in the maxillary sinus, condylar hypoplasia). Differences between groups were tested by the Fisher's exact test and chi-square test (p<0.05).

RESULTS

For intrarater agreement, Kappa values were 0.76 to 0.85. The presence of supernumerary teeth (p=0.003); conoid teeth (p=0.009); taurodontism (p<0.001); impacted teeth (p<0.001); partial bony teeth (p=0.040); complete bony teeth (p=0.013); and root dilaceration (p=0.047) were statistically more frequent in MPS individuals compared to non-MPS individuals. Bone rarefaction/furcation lesions (p=0.032), condylar hypoplasia (p<0.001), radiolucent bone lesions (p=0.001), and dentigerous cysts (p=0.002) were also more frequent in MPS individuals.

CONCLUSION

The presence of specific oral manifestations is more common in MPS individuals than non-MPS individuals.

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.

A novel three-dimensional morphological analysis of idiopathic condylar resorption following stabilisation splint treatment

Bone modelling evaluation is important for monitoring idiopathic condylar resorption (ICR) progress. To compare condylar modelling in ICR patients treated with or without stabilisation splints (SSs). Eighty-four condyles from 84 ICR patients were studied: 42 received SS therapy (SS group); 42 received conventional therapy (control group). Cone-beam computed tomography images at diagnosis (T0) and after at least 6 months (T1) were used for three-dimensional reconstruction. Volume differences between T0 and T1 (δV) were used to evaluate the amount of modelling. Percentage of growth area (PCT) was used to assess the condylar surface growth tendency. No significant change in condylar volume was found in the SS group, whereas that in the control group was significantly decreased at T1 (P <.0001). The amount of modelling differed among condylar subregions within the SS group: among 6 subregions (P =.0137), between anterior and posterior regions (P =.0336) and between lateral, intermediate and medial regions (P =.0275). Control group condylar subregions showed no significant differences in the amount of modelling. The anabolic modelling tendency of the total condylar surface in the SS group was greater than that in the control group (P =.0251); however, there were no statistical differences in PCTs among condylar subregions in either group. SS therapy effectively reduced further bone destruction and promoted condylar modelling. Three-dimensional morphological analysis is a novel method that can accurately evaluate the amount of bone modelling and growth tendency in ICR patients.

Alloplastic Temporomandibular Joint Reconstruction in Congenital Craniofacial Deformities

ABSTRACT

Temporomandibular joint (TMJ) reconstruction with alloplastic prosthesis is a commonly performed procedure, which can be used as a treatment for improving pathologic conditions affecting the TMJ. Depending of the severity of the condition, the patient's ability to eat can be impaired, which in turn can affect their quality of life. Several syndromes can affect the patient's facial features, and some of those also affect TMJ's. Use of alloplastic prosthesis in TMJ's affecting syndromes, by means of correcting TMJ conditions and mandibular deformities, is still rather uncommon. Purpose of our study is to review the use TMJ total prosthesis as a treatment modality for correcting TMJ conditions and the reconstruction of mandibular deformities in congenital syndromes affecting the facial features. This study consists of a retrospective cohort of patients treated with TMJ reconstruction with alloplastic prosthesis at the Helsinki University Hospital during the past decade. All subjects with congenital syndrome who underwent TMJ reconstruction were included the study. The cohort consisted of seven patients and ten joints treated. Temporomandibular joints affecting syndromes were Goldenhar syndrome, hemifacial macrosomia, Nager syndrome, and Treacher-Collins syndrome. The majority of the patients have had several previous operative treatments on the facial skeleton during their childhood, which in turn probably affected and compromised the TMJ surgery outcome. Mouth opening was sufficiently achieved as average maximal opening was 34 mm (range 24-42 mm) postoperatively. Temporomandibular joint reconstruction with alloplastic prosthesis can offer new tools and approaches for treatment of facial deformities in syndromes with craniofacial abnormalities. Impaired jaw functions and asymmetry can be addressed with the use of alloplastic prostheses, achieving sufficient mouth opening and restoring the symmetry of the lower facial skeleton.

Facial Asymmetry in Unilateral Condylar Hyperplasia: Comparing Treatment for Active versus Burnt-Out Disease

BACKGROUND

Facial asymmetry caused by unilateral condylar hyperplasia requires treatment to address facial and occlusal imbalances. There is no definitive evidence to suggest that a single intervention strategy (during either active condylar overgrowth or the burnt-out phase) results in better/more symmetric correction. This study sought to quantify preoperative and postoperative facial asymmetry in unilateral condylar hyperplasia patients comparing treatment for active versus burnt-out disease.

METHODS

Preoperative and postoperative three-dimensional photographs were obtained. Images were compared to those of unaffected controls as a standard for normal facial symmetry. Facial asymmetry was assessed using root-mean-square deviation. Paired t tests were performed to compare the root-mean-square deviations of preoperative and postoperative images between the unilateral condylar hyperplasia groups and against controls.

RESULTS

Forty patients were included (11 active, nine burnt-out, and 20 controls) and 60 three-dimensional images were evaluated. Preoperatively, patients in the burnt-out group had worse asymmetry than those with active unilateral condylar hyperplasia (p = 0.011). Both groups demonstrated significantly improved symmetry postoperatively (active, p = 0.0069; burnt-out, p = 1.74E-4). However, burnt-out patients remained with some residual asymmetry (p = 4.75E-4), whereas their active counterparts showed no significant difference compared to unaffected controls (p = 0.089).

CONCLUSIONS

Patients with end-stage unilateral condylar hyperplasia have more severe facial asymmetry that is more difficult to normalize compared to earlier intervention during active unilateral condylar hyperplasia. These findings suggest that, if possible, corrective intervention is preferable during active unilateral condylar hyperplasia.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, II.

Evaluation of vertical ramus osteotomy for the surgical correction of unilateral mandibular posterior vertical insufficiency: Long-term follow-up results

PURPOSE

Unilateral posterior vertical insufficiency (PVI) is a growth defect of the mandibular condyle that results in a facial asymmetry. Various surgical procedures can be used to elongate the hypoplastic ramus. The aim of this study was to evaluate long-term aesthetic and architectural outcomes of vertical ramus osteotomy (VRO) in patients with unilateral PVI.

MATERIALS AND METHODS

Patients operated on with unilateral VRO were included in this retrospective study. Aesthetic and architectural parameters were evaluated on frontal photographs as well as on frontal and lateral cephalograms preoperatively, postoperatively, at 1-year and at the end of the follow-up.

RESULTS

A total of 48 patients were analyzed. The aesthetic assessment revealed significant correction of the chin deviation (CD) and of the lip commissural line tilt after VRO (p1 = 0.0038 and p2 = 0.0067, respectively) with stable results. The architectural analysis revealed significant improvement in the maxillary and mandibular occlusal planes, as well as the chin deviation (p < 0.0001). A tendency to relapse was noted for the mandibular canting and the CD during the follow-up. VRO allowed for a mean mandibular lengthening of 8.39 mm (ranging from 2.5 to 14 mm).

CONCLUSION

VRO allows for immediate restoration of the symmetry of the lower third of the face in patients with unilateral PVI. A revisional procedure may be needed due to a tendency for the chin deviation to relapse.

Is Temporomandibular Joint Arthroscopy Effective in Managing Pediatric Temporomandibular Joint Disorders in the Short- and Long-Term?

PURPOSE

Although temporomandibular joint (TMJ) arthroscopy outcomes have been well documented in the adult population, conclusive data are lacking for pediatric patients with TMJ disorders. The aim of the present study was to evaluate the early and late outcomes of TMJ arthroscopy in the pediatric population.

PATIENTS AND METHODS

We performed a retrospective analysis to evaluate the short- (1-month) and long-term (1-year) improvements in the visual analog scale (VAS) scores for pain after pediatric TMJ arthroscopy from 2008 to 2016. The arthroscopic interventions varied according to the diagnostic findings and Wilkes classification. The primary outcome variable was the magnitude of VAS score for pain (0, no pain; 100, worst pain) at 1 year postoperatively. The secondary outcome variables were the short-term for the VAS score for pain and the short- and long-term outcomes for perceived jaw dysfunction (0, normal jaw function; 100, complete jaw dysfunction), mouth opening, joint loading (contralateral joint pain when biting on the canine), joint noise, and muscle pain. Univariate, bivariate, and multivariate statistical analyses were performed with the significance level set at P < .05.

RESULTS

A total of 23 patients (37 joints), with a mean age of 14.1 years (range, 12.8 to 16.7 years) had undergone TMJ arthroscopic surgery with short- and long-term postoperative follow-up data available. The VAS scores for pain showed average improvements of 26% in the short-term (P < .0001) and 25% in the long-term (P < .0008). Perceived jaw dysfunction showed an average improvement of 23.8% in the short-term (P < .0001) and 19.2% in the long-term (P < .0008). The average mouth opening had improved by 5.4 mm in the short-term (P < .0016) and 8.2 mm in the long-term (P < .0001). Controlling for stage and diagnosis, the patients with Wilkes III showed the most benefit with statistically significant improvements in pain, jaw dysfunction, maximum interincisal opening, and joint loading pain.

CONCLUSIONS

TMJ arthroscopy could be an effective and minimally invasive form of surgical intervention for treating Wilkes II, III, and IV TMJ disorders in the pediatric population.