Pediatric internal derangements of the temporomandibular joint: effect on facial development

Influence of feeding a soft diet on proteoglycan expression in rat temporomandibular joint discs

OBJECTIVES

Extracellular matrix components play a significant role in maintaining tissue integrity and pathological processes of the temporomandibular joint (TMJ). This study aimed to evaluate the influence of a soft diet on the mRNA expression of proteoglycans and glycosaminoglycans (GAGs) linked to proteoglycan core proteins in rat TMJ discs.

METHODS

Thirty 4-week-old male Wistar rats were assigned to one of two groups: a control group fed a regular pellet diet and a soft diet group fed a powdered diet for 4 weeks. The mRNA expression levels of 12 proteoglycans in TMJ discs were evaluated using real-time polymerase chain reaction (PCR). In addition, histomorphometric and biochemical analyses were performed to evaluate the thickness and deoxyribonucleic acid (DNA), GAG, and water content of the TMJ discs.

RESULTS

The TMJ disc thickness in the anterior, intermediate, and posterior bands decreased significantly in the soft diet group. The GAG content decreased significantly in the soft-diet group, whereas no significant differences in DNA content or water content ratio were observed between the groups. Real-time PCR indicated that the expression levels of aggrecan, versican, biglycan, decorin, fibromodulin, lumican, and chondroadherin decreased in the soft diet group. The expression levels of all versican isoforms decreased in the soft diet group.

CONCLUSIONS

These results indicate that the biomechanical environment of the TMJ caused by a soft diet is closely related to the expression of proteoglycans in TMJ discs, which may eventually increase the fragility of the TMJ discs.

Effect of arthroscopic discopexy on condylar growth in adolescents with temporomandibular joint disc displacement without reduction: A retrospective self-controlled case series study

This study was a retrospective self-controlled study that aimed to evaluate the effect of arthroscopic discopexy on condylar height and mandibular position in adolescents with temporomandibular joint (TMJ) anterior disc displacement without reduction (ADDwoR). Patients between 10 and 20 years of age and diagnosed with bilateral TMJ ADDwoR by magnetic resonance image (MRI) were included in this study. All patients underwent a period of natural course before arthroscopic surgery and then a follow-up period postoperatively. Changes in condylar height and mandibular position were measured by MRI and X-ray radiographs. Data were analyzed by paired t-test, Pearson correlation analysis, and generalized estimating equations. This study comprised a total of 40 patients with a mean age of 14.80 years. Pearson correlation analysis showed correlations between condylar height and mandibular position changes. The condylar height change during the post-operative period was significantly higher than that during natural course period (3.57 mm, p < 0.001). The changes in mandibular position (including ANB angle, SNB angle, and Pog-Np) were significant different (all p < 0.05) between the two periods. This study found that arthroscopic discopexy can promote condylar growth and correct dentofacial deformity in adolescents with bilateral TMJ ADDwoR.

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

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

Temporomandibular joint disc repositioning and occlusal splint for adolescents with skeletal class II malocclusion: a single-center, randomized, open-label trial

BACKGROUND

Temporomandibular joint (TMJ) disc repositioning through open suturing (OSu) is a new disc repositioning method. Its result for adolescents with condylar resorption and dentofacial deformities combined with and without postoperative occlusal splints (POS) has not been well studied.

OBJECTIVE

This study was to evaluate and compare the effects of OSu with and without POS in the treatment of TMJ anterior disc displacement without reduction (ADDwoR) in adolescent skeletal Class II malocclusion.

METHODS

A total of 60 adolescents with bilateral ADDwoR were enrolled in this study. They were randomly allocated into two groups: OSu with and without POS. Magnetic resonance imaging (MRI) and lateral cephalometric radiographs were used to measure changes in condylar height and the degree of skeletal Class II malocclusion from before operation and at 12 months postoperatively. Changes in these indicators were compared within and between the two groups.

RESULTS

After OSu, both groups exhibited significant improvements in condylar height and occlusion at the end of 12 months follow-up (P < 0.05). The group of OSu with POS had significantly more new bone formation (2.83 ± 0.75 mm vs. 1.42 ± 0.81 mm, P < 0.001) and improvement in dentofacial deformity than the group of OSu only (P < 0.05). The new bone height was significantly correlated with POS (P < 0.001), the changes of SNB (P = 0.018), overjet (P = 0.012), and Wits appraisal (P < 0.001).

CONCLUSION

These findings indicated that OSu can effectively stimulate condylar regeneration and improve skeletal Class II malocclusion in adolescents with bilateral ADDwoR. The results are better when combined with POS.

TRIAL REGISTRATION

This trial was prospectively registered on the chictr.org.cn registry with ID: ChiCTR1900021821 on 11/03/2019.

Review of the studies on the relationship and treatment of anterior disc displacement and dentofacial deformity in adolescents

Anterior disk displacement (ADD) is a common type of temporomandibular joint (TMJ) internal derangement. In adolescents, the relationship between ADD and dentofacial deformities are brought into focus. Whether treatment is needed, or what kind of treatment are effective are still without a consensus. From the literature review, the consequences of ADD without treatment and the effect on disk repositioning were summarized. The results showed that after ADD, condylar height was prone to reduce that may lead to or aggravate dentofacial deformities in adolescents. Disk repositioning could promote the regeneration of condylar bone, thus improving the development of dentofacial deformities.

Evaluation of Mandibular Growth and Symmetry in Child with Congenital Zygomatic-Coronoid Ankylosis

Ankyloses in the area of the temporomandibular joint (TMJ) are mentioned as a potential etiological factor of mandibular growth disorders and facial asymmetry. The aim of this case study was to evaluate the changes in the mandible of a child with zygomatic-coronoid ankylosis during the first five years of life, in which two adhesion release procedures were performed. The adopted symmetrical approach is based on the assumption of symmetry of the structure of the stomatognathic system in relation to the sagittal median plane. However, the assessment of pathological changes in the structure of the skeletal system was performed using an asymmetrical approach. Computed tomography techniques and a system of computer-aided diagnosis (CAD) were used in the case study. During the child’s growth, linear and angular measurements were made thrice (at the age of 16, 25 and 54 months). The degree of asymmetry was estimated in the measurements made on the right and left sides of the three-dimensional mandible. Unilateral congenital hypoplasia of the articular process and zygomatic-coronoid adhesion caused asymmetrical growth of the mandible in the child along with shortening of the mandibular branch and body on the damaged side and a visible difference in the size of the mandibular angles. Removal of the adhesions during surgical procedures made it possible to reduce the asymmetry of the mandible and catch-up growth, although at the age of five, the mandible was still smaller than the mandible in healthy peers. It was shown that the early adhesion release procedures supported by the CAD analysis enabled the restoration of mandibular symmetry.

Relationship between rotational disc displacement of the temporomandibular joint and the dentoskeletal morphology

Objective

The purpose of this study was to evaluate the relationship between rotational disk displacement (DD) of the temporomandibular joint (TMJ) and the dentoskeletal morphology.

Methods

Women aged > 17 years were included in this study. Each subject had a primary complaint of malocclusion and underwent routine cephalometric examinations. They were divided into five groups according to the findings on sagittal and coronal magnetic resonance images of their TMJs bilateral normal disk position, bilateral anterior DD with reduction (ADDR), bilateral rotational DD with reduction (RDDR), bilateral anterior DD without reduction (ADDNR), and bilateral rotational DD without reduction (RDDNR). Twenty-three cephalometric variables were analyzed, and the Kruskal–Wallis test was used to evaluate differences in the dentoskeletal morphology among the five groups.

Results

Patients with TMJ DD exhibited a hyperdivergent pattern with a retrognathic mandible, unlike those with a normal disk position. These specific skeletal characteristics were more severe in patients exhibiting DD without reduction than in those with reduction, regardless of the presence of rotational DD. Rotational DD significantly influenced horizontal and vertical skeletal patterns only in the stage of DD with reduction, and the mandible exhibited a more backward position and rotation in patients with RDDR than in those with ADDR. However, there were no significant dentoskeletal differences between ADDNR and RDDNR.

Conclusions

The results of this study suggest that rotational DD of TMJ plays an important role in the dentoskeletal morphology, particularly in patients showing DD with reduction.

The Effect of Condylar Regeneration After Different Disc Repositioning Surgeries in Adolescents with Skeletal Class II Malocclusion

PURPOSE

To evaluate the effect of different temporomandibular joint (TMJ) disc repositioning surgeries for the treatment of anterior disc displacement (ADD) in juvenile patients with skeletal Class II malocclusion.

PATIENTS AND METHODS

Patients (< 20 years, cervical vertebral maturation stage, IV-V) who had bilateral TMJ ADD with skeletal Class II malocclusion were treated by disc repositioning surgery (mini-screw anchor, [MsA]; or opening suturing, [OSu]). Magnetic resonance imaging (MRI) and lateral cephalometric films before and more than 12 months after surgery were collected from all patients. Changes of SNA, SNB, ANB, incisor overjet, pogonion position (pg'-G'), and condylar height were measured before and after surgery in different disc reposition surgeries and compared by statistical analysis.

RESULTS

Eighty-four patients with an average age of 16.44 years and follow-up time of 14.60 months (12 to 33 months) were included in the study. Among them, 16 patients had a mean follow-up of 14.8 months without treatment before disc repositioning. Their condylar height was significantly decreased (P = .004) by MRI measurement. Six patients who had cephalometric films showed significantly decreased SNB (P = .042) and increased overjet (P = .037). After disc repositioning by either OSu (54 cases) or MsA (30 cases), condylar height, SNB were significantly increased and overjet, Pg'-G', ANB were decreased in both groups (P < 0.001). There was more new bone height in OSu than MsA (P = .004), but no significant differences in SNB, ANB, overjet and Pg'-G' between the 2 groups (P > .05). The new bone height was significantly correlated with the surgical method (P = .029), age (P = .015), SNB (P = .008), overjet (P = .048) and pg'-G' (P = .001).

CONCLUSIONS

Both types of disc repositioning method can effectively promote condylar regeneration and improve skeletal Class II malocclusion in adolescents with ADD. Disc repositioning by OSu obtained more new bone height than MsA.

The effect of TMJ disk repositioning by suturing through open incision on adolescent mandibular asymmetry with and without a functional orthodontic appliance

OBJECTIVE

The objective of this study was to evaluate the effect of combined temporomandibular joint (TMJ) disk repositioning by suturing through open incision and orthodontic functional appliance (OFA) treatment for adolescents with mandibular asymmetry.

STUDY DESIGN

Adolescent patients (12-20 years old) with mandibular asymmetry combined with unilateral TMJ disk displacement without reduction were treated with disk repositioning by suturing through open incision with and without postoperative OFA. Magnetic resonance imaging and posteroanterior cephalometric radiographs (PA) were used to measure and compare the changes in condylar height, joint space, and menton deviation pre- and postoperatively.

RESULTS

Twenty-six patients were included in the study. Joint space was significantly increased postoperatively and new bone mostly formed at the superior or posterior superior part of the condyle after 6 to 18 months in all surgically treated joints. Fourteen patients with OFA had a significant increase in condylar height and menton deviation compared to 12 patients without OFA (2.29 ± 0.91 mm vs 1.22 ± 0.69 mm, P = .003; 4.56 ± 1.48 mm vs 2.01 ± 0.74 mm, P = .000).

CONCLUSIONS

Combined treatment with TMJ disk repositioning by suturing through open incision and OFA can promote condylar growth and correct mandibular deviation in adolescent patients. Postoperative OFA can maintain the increased joint space created by disk repositioning and promote new bone formation at the superior and posterior parts of the condyle.

Diagnosing mandibular asymmetry using posteroanterior cephalograms in patients with unilateral and bilateral degenerative joint disease

Objectives:

The purpose of this study was to evaluate the possible differences in facial asymmetry between bilateral degenerative joint disease (BDJD) and unilateral degenerative joint disease (UDJD) when compared to asymptomatic controls.

Materials and Methods:

Posteroanterior cephalograms of 61 pre-orthodontic treatment patients (21 BDJD, 20 UDJD, and 20 controls) were evaluated (young adults, between 12 and 25 years of age) to investigate the inclination of the frontal occlusal plane (FOP) and frontal mandibular plane (FMP) to determine vertical asymmetry. Mandibular dental midline shift (DMS) and mandibular midline shift (MMS) were studied to determine transverse asymmetry. FOP, FMP, MMS, and DMS were compared pairwise between study groups, with multiple comparisons justified by Tukey–Kramer procedure. Correlation analyses were performed to evaluate the relationship between the measures. Mantel–Haenszel Chi-square test was used to evaluate the association between groups and symptom severity.

Results:

The findings suggest that severity of the vertical mandibular displacement was associated with significant differences between BDJD and control patients, and between UDJD groups and control patients. However, they were no significant differences found between UDJD and BDJD patients, and this may be attributable to a different pattern of load on the ipsilateral and contralateral sides of the TMJ when they were compared to the controls. Moreover, the higher values of FOP and FMP correlated with the mandibular displacement being notably greater when the asymmetry was >3°. A similar tendency of a higher prevalence of mandibular displacement with a higher value of DMS and MMS was observed.

Conclusion:

Clinical implications of this study apply to patients with asymmetry in vertical and transverse dimensions. These patients should be evaluated for dental, skeletal (condylar changes), and soft-tissue changes before orthodontic and/or orthognathic treatment planning.

Relations between anterior disc displacement and maxillomandibular morphology in skeletal anterior open bite with changes to the mandibular condyle

In this study we investigated the relation between anterior disc displacement (ADD) and maxillomandibular morphology in skeletal anterior open bite with changes to the mandibular condyle. Thirty female patients (60 joints) with both conditions were evaluated. Magnetic resonance imaging of the temporomandibular joint (TMJ) was used to diagnose both ADD and changes to the mandibular condyle (erosion, osteophyte, and deformity). The relations among ADD, changes to the mandibular condyle, and maxillomandibular morphology were examined statistically. Changes to the mandibular condyle had a higher score than sym anterior open bite, the deviated side in asymmetric anterior open bite, and the non-deviated side. The score for disc displacement on the non-deviated side was lower than both the sym side and the deviated side. Unilateral changes to the mandibular condyle and unilateral disc displacement were not apparent in sym anterior open bite, but a unilateral non-displaced disc was seen only on the asymmetric side. Mandibular condylar changes were significantly more common on the deviated, than on the non-deviated, side. The SNB angle was significantly smaller, and the ANB, GZN, and SN-mandibular plane angles were significantly larger in sym anterior open bite. Overjet, ANB angle, GZN angle, and SN-MP angle were significantly larger, and the SNB angle was significantly smaller, in the presence of ADD without reduction and mandibular condylar deformity. We conclude that the prevalence of ADD without reduction and changes to the mandibular condyle were related to mandibular asymmetry and mandibular morphology in anterior open bite. This retrospective study suggests that ADD without reduction and mandibular condylar bone changes may be related to the progression of skeletal class II open bite and mandibular asymmetry in cases of skeletal open bite.

Stability of Orthognathic Surgery in the Treatment of Condylar Osteochondroma Combined With Jaw Deformity by CT Measurements

PURPOSE

We evaluated the stability of orthognathic surgery in the treatment of unilateral condylar osteochondroma combined with jaw deformity.

PATIENTS AND METHODS

Patients with unilateral condylar osteochondroma and jaw deviation deformity who had undergone surgery at the Ninth People's Hospital of Shanghai Jiaotong University School of Medicine from July 2014 to March 2017 were enrolled. The operation included a low condylectomy and both Le Fort I osteotomy and bilateral mandibular sagittal split osteotomies. ProPlan CMF, version 1.4, software (Materialise, Leuven, Belgium) was used to reconstruct and measure the preoperative, immediately postoperative, and follow-up (>6 months) maxillofacial computed tomography images. The position of the jaw and contralateral condyle and remodeling of the affected side were compared during follow-up.

RESULTS

Eight patients were included in the present study. The canting of the maxilla was significantly decreased postoperatively, and the contralateral condyle had rotated inward. The position of the maxillary and contralateral condyles was stable during follow-up, and the posterior aspect of the affected condyle demonstrated significant resorption.

CONCLUSIONS

The results of single-stage surgery combined with orthognathic surgery and condylar osteochondroma resection were stable, and the affected condyle stump had adaptively reconstructed.

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.

Assessment of Occlusal Appliance for the Reposition of Temporomandibular Joint Anterior Disc Displacement With Reduction

The aim of our study was to evaluate the success rates and prognoses of patients treated with occlusal appliances used to reposition the temporomandibular joint anterior disc displacement with reduction (ADDWR). A sample of 144 consecutive patients (210 joints) diagnosed with ADDWR based on MRI were included in our study. Disc recapture was confirmed in a mandible-anterior position to eliminate joint clicking based on magnetic resonance imaging (MRI). Anterior repositioning appliance (ARS) was applied to keep the mandible in this position. The occlusal surface of the ARS was ground down by 1 mm approximately every 4 weeks for bite reconstruction. MRI was carried out before treatment, 6 months after the start of treatment, at the end of the treatment, and at their last follow-up visit. A Cox regression model was used to estimate the risk of failure of the treatment. The mean treatment duration was 9.5±2.6 months. A total of 177 joints (84.3%) were successfully repositioned at the end of splint treatment according to MRI. Regular follow-up indicated that almost 53% of the patients had normal disc-condyle relationships after 2 years. Sex, age, treatment duration, and orthodontics used were included in the final Cox regression model, with hazard ratios of 1.375, 1.141, 0.396, and 0.364, respectively. ARS is inferior for recapturing ADDWR in the long-term. It is thus better to explore other more effective methods to reposition the displaced disc in patients with ADDWR.

Yang's Classification of Juvenile TMJ Anterior Disc Displacement Contributing to Treatment protocols

This study aims to establish a new staging system of temporomandibular joint (TMJ) anterior disc displacement (ADD) and evaluate its role in guiding the treatment plan. A consecutive sample of 522 juvenile patients (780 joints) diagnosed as ADD based on magnetic resonance imaging (MRI) was included and analyzed. 674 joints received TMJ treatments according to our staging system, while 106 joints rejected any treatment; only for follow-up. The outcomes were judged according to our success criteria. The prognosis of our staging system was also evaluated in comparison to Wilkes classification. Kaplan–Meier survival analysis showed that significant stratifications of the ameliorative rate were found at all subgroups within any two stages in our staging system, except for subgroups between stages 0 and 1, stages 2 and 3, and stages 3 and 4. After analyzing the interactions between different candidate prognostic factors in a Cox model, the relative risks of deterioration of ADD included treatment methods (HR = 42.94, P < 0.0001), disease course (HR = 0.98, P = 0.0019), stages of ADD (HR = 3.81, 9.62, 12.14, P = 0.016, 0.000,0.000 respectively for stage 2, stage 3 and stage 4) and the interaction between ADD stages and treatment methods. The C index of this model was 0.87. The new staging system of TMJ ADD appears reliable, and benefits to making treatment planning and predicting the prognosis.

Changes of temporomandibular joint position after surgery first orthognathic treatment concept

Orthognathic surgery treatment (OGS) after orthodontic treatment of dentofacial deformities is a widely performed procedure, often accompanied by a bilateral sagittal split osteotomy (BSSO). Positioning of the condyle during this procedure is a crucial step for achieving optimal functional and anatomical results. Intraoperatively poorly positioned condyles can have a negative effect on the postoperative result and the patient’s well-being. Changes of the condylar position during OGS Procedures and its effects on the temporomandibular joint in orthognathic surgical interventions (OGS) are subject of scientific discussions. However, up to date, no study has investigated the role of condyle position in the surgery first treatment concept. The aim of this study was to investigate the influence of OGS on the three-dimensional position of the condyle in the joint in a surgery first treatment concept without positioning device and to record the change in position quantitatively and qualitatively. Analysis of our data indicated that OGS in surgery first treatment concept has no significant effect on the position of the condyle and the anatomy of the temporomandibular joint.

Adaptive change in temporomandibular joint tissue and mandibular morphology following surgically induced anterior disc displacement by bFGF injection in a rabbit model

PURPOSE

The purpose of this study was to examine the effect of injecting basic fibroblast growth factor following surgical induced anterior disc displacement in temporomandibular joints (TMJ).

MATERIALS AND METHODS

Adult male Japanese white rabbits (n = 16; 2.0-2.5 kg; 10 weeks old) were assigned to experimental and control groups. In the experimental group, anterior disc displacement was induced in the bilateral TMJ. Recombinant human basic fibroblast growth factor (rh bFGF) 0.1 μg/1 μL aqueous solution was injected into the left retro-discal connective tissue close to the disc (ADL group), and saline alone was injected into the same site on the right (ADR group). In the control group, a sham operation without disc position change was performed in the bilateral TMJ (CR group and CL group). Four animals from the experimental (ADR and ADL) and control (CR and CL) groups were sacrificed at 1 and 12 weeks postoperatively to evaluate the mandibular morphology and computed tomographic (CT) value of the condylar head, using 3 dimensional computed tomography. Furthermore, cartilage layers and disc tissue were examined histologically.

RESULTS

Regarding CT value at the 0° site of the condylar surface, ADR showed the lowest value after 1 week (P = 0.0325). However, there were no significant differences among the 4 groups regarding CT values at the other degree sites after 1 and 12 weeks. Regarding mandibular length, ADR showed the lowest value after 12 weeks (P = 0.0079). In condylar width, ADR showed the lowest value after 1 week (P = 0.0097).

CONCLUSION

This study suggested that surgically induced anterior disc displacement could affect condylar morphology in the early stage, and could decrease mandibular length in the late stage. However, bFGF injection into the TMJ might prevent the degenerative change derived from anterior disc displacement and inhibition of sequential mandibular growth.

Incidence of anterior disc displacement without reduction of the temporomandibular joint in patients with dentofacial deformity

The aim of this study was to investigate the incidence of anterior disc displacement without reduction (ADDwoR) of the temporomandibular joint (TMJ) in patients with dentofacial deformity. Eighty-eight female patients (176 joints) with skeletal class III malocclusion and 33 female patients (66 joints) with skeletal class II malocclusion, with or without anterior open bite and asymmetry, were evaluated. Magnetic resonance imaging (MRI) of the TMJ was used to diagnose ADDwoR. A statistical analysis was performed to examine the relationship between ADDwoR and skeletal structure. ADDwoR was present in 37 of the 66 joints (56.1%) in class II compared to 34 of the 176 joints (19.3%) in class III (P<0.05). In class III, ADDwoR was significantly more common in joints with mandibular asymmetry (24/74; 32.4%) than in joints with open bite (9/62; 14.5%) and joints with open bite and without mandibular asymmetry (1/38; 2.6%). In class II, ADDwoR was significantly less common in joints with mandibular asymmetry and without open bite (1/8; 12.5%). ADDwoR was only observed on the deviated side in both class III and class II with mandibular asymmetry. The prevalence of ADDwoR differed according to the dentofacial morphology.

Impact of Temporomandibular Joint Discectomy on Condyle Morphology: An Animal Study

PURPOSE

Temporomandibular disorders lead to parafunctional activity that may alter bone remodeling of mandibular components. This animal study aimed to assess the impact of temporomandibular joint discectomy on condylar bone microarchitecture.

MATERIALS AND METHODS

A total of 30 one-month-old Wistar rats were assessed and divided into 3 equal groups (2 test groups and 1 control group) of 10. The first test group underwent disc removal, the second test group underwent disc and condylar cartilage removal, and the 10 remaining rats were analyzed as sham-operated controls, following a split-mouth design. The rats were killed humanely 2 months after surgery, and the respective mandibles were scanned with micro-computed tomography for quantitative morphometric analysis.

RESULTS

There were significant differences among the 3 groups analyzed (disc removal, disc and condylar cartilage removal, and sham-operated control) for bone volume fraction (ratio of bone volume to total volume, P = .044), structure model index (P < .001), fractal dimension (P = .024), and porosity (P = .023). In addition, operated and contralateral nonoperated sides significantly differed for all variables in at least 1 of the test groups (P < .05) but not in the control group (P > .05).

CONCLUSIONS

Within the limitations of this study, our results suggest that discectomy may lead to alterations of the mandibular condylar morphology.

Complications associated with orthognathic surgery

While most patients undergo orthognathic surgery for aesthetic purposes, aesthetic improvements are most often followed by postoperative functional complications. Therefore, patients must carefully decide whether their purpose of undergoing orthognathic surgery lies on the aesthetic side or the functional side. There is a wide variety of complications associated with orthognathic surgery. There should be a clear distinction between malpractice and complications. Complications can be resolved without any serious problems if the cause is detected early and adequate treatment provided. Oral and maxillofacial surgeons must have a full understanding of the types, causes, and treatment of complications, and should deliver this information to patients who develop these complications.

Role of articular disc in cartilaginous growth of the mandible in rats

Displacement of the temporomandibular joint (TMJ) disc causes a lateral shift of the mandible and less-developed and/or distally located mandible unilaterally and bilaterally, respectively, if occurred in growing individuals. The purpose of this study was to evaluate mandibular condylar growth in growing rats after TMJ discectomy and to explore a certain significant role of articular disc in the TMJ in mandibular or cartilaginous growth. Eighteen 4-week-old Wistar strain male rats were divided into two groups with nine in each group, i.e., rats with TMJ discectomy (discectomy group) and only sham operation (control group). Four weeks after initiating the experiment, morphometric analyses of the mandible were performed using a rat and mouse cephalometer and micro-computed tomography. Then, the mandibular condyles were subjected to histomorphometric analyses. Condylar and mandibular growth was reduced significantly in the discectomy group than in the control group. In the discectomy group, the condyle also became flatter and smaller. In addition, the 4-layer structure of condylar cartilage was unclear with thicker fibrous and thinner lower hypertrophic layers in the discectomy group when compared to the controls. It is shown that resection of the articular disc substantially affects condylar and mandibular growth in terms of the cartilaginous growth, suggesting that TMJ disc is indispensable for maintaining normal growth of the condyle and mandible, leading to optimal development of the TMJ and the entire mandible.

Bilateral TMJ Disk Displacement Induces Mandibular Retrognathia

Unilateral non-reducing TMJ disk displacement has been shown to retard mandibular growth on the ipsilateral side, with facial asymmetry a sequela. We hypothesized that bilateral affliction would impair mandibular growth bilaterally, generating mandibular retrognathia. Non-reducing TMJ disk displacement was surgically created in 10 growing New Zealand White rabbits. Ten additional rabbits served as a sham-operated control group. Facial growth was followed in serial cephalograms, with tantalum implants, during a period corresponding to childhood and adolescence in man. The results verified that bilateral non-reducing TMJ disk displacement retarded mandibular growth bilaterally, the extent corresponding to mandibular retrognathia in man. Maxillary growth was also retarded, but to a lesser degree. Growth impairment fluctuated over time, the most striking retardation occurring during periods of general growth acceleration. This should be taken into consideration when orthodontic treatment, aimed at stimulating mandibular growth, is initiated in adolescent individuals with non-reducing TMJ disk displacement.

The Relationship Between Retruded Contact Position and Intercuspal Position in Patients with TMJ Osteoarthritis

This study was conducted to investigate the relationship between posterior mandibular excursion movement and temporomandibular joint osteoarthntis (TMJ OA) in 25 orthodontic patients with Angle Class I and Class II, using a six degrees-of-freedom measuring device and helical computed tomography. There were significant differences found in three-dimensional length, antero-posterior, absolute latero-medial and supero-inferior incisal, and condylar intercuspal position (IP)-retruded contact position (RCP) slides between bilateral, unilateral, and no condylar bone change groups. With respect to the types of condylar bone change, there were significant differences found in three-dimensional length, antero-postenor, and absolute latero-medial condylar IP-RCP slides between flattening, erosion and osteophyte groups. These results suggest that large three-dimensional, not only incisal but also condylar, IP-RCP slides might be related to the uni-/bilaterality and kind of TMJ pathosis, which might make such slides useful as clinical indices of TMJ OA.

TMD and chronic pain: a current view

This review aims at presenting a current view on the physiopathologic mechanisms associated with temporomandibular disorders (TMDs). While joint pain is characterized by a well-defined inflammatory process mediated by tumor necrosis factor-α and interleukin, chronic muscle pain presents with enigmatic physiopathologic mechanisms, being considered a functional pain syndrome similar to fibromyalgia, irritable bowel syndrome, interstitial cystitis and chronic fatigue syndrome. Central sensitization is the common factor unifying these conditions, and may be influenced by the autonomic nervous system and genetic polymorphisms. Thus, TMDs symptoms should be understood as a complex response which might get worse or improve depending on an individual's adaptation.

Features in subjects with the frontal occlusal plane inclined toward the contralateral side of the mandibular deviation

INTRODUCTION

The frontal occlusal plane of the maxilla generally inclines toward the ipsilateral side of the mandibular deviation in subjects with facial asymmetry; however, a few patients with facial asymmetry have their frontal occlusal planes inclined toward the contralateral side. We aimed to investigate the morphologic and functional features of such patients.

METHODS

The subjects were 40 patients with facial asymmetry divided into 2 groups based on the inclination of the frontal occlusal plane toward the ipsilateral or the contralateral side. We analyzed lateral and posteroanterior cephalometric radiographs and occlusal variables and evaluated temporomandibular joint symptoms. Statistical comparisons were performed between the 2 groups (P <0.05).

RESULTS

The posteroanterior cephalometry significantly differed between the ipsilateral and contralateral groups. Occlusal force and occlusal contact area were significantly larger, and temporomandibular joint symptoms were more frequently found on the side of the upward-inclined frontal occlusal plane than on the opposite side in both groups.

CONCLUSIONS

The features in the contralateral group in terms of occlusal force and temporomandibular disorders were clinically significant. Clinicians should note that the conditions associated with the contralateral group require less presurgical decompensation.

Surgical treatment of adolescent internal condylar resorption (AICR) with articular disc repositioning and orthognathic surgery in the growing patient--a pilot study

Background

The aim of this study was to better understand how surgical repositioning and stabilization of anteriorly displaced articular discs using the Mitek mini-anchor technique affects condylar growth in growing patients with adolescent internal condylar resorption (AICR).

Methods

Twenty-two adolescent patients diagnosed with AICR and anterior temporomandibular disc displacement were compared to untreated control subjects without AICR matched for age, sex, and Angle classification. Pre-surgical (T1 and T2) and post-surgical (T3 and T4) mandibular tracings were superimposed on natural stable structures to evaluate the horizontal, vertical, and total changes in the position of condylion.

Results

The treated group showed an overall decrease in condylar height pre-surgically and statistically significant changes in condylar growth direction between the pre- and post-surgical observation periods. Pre-surgically, the treated group showed significantly more posterior condylar growth than the control group; they also showed inferior condylar growth, while the controls showed superior growth. Controls and patients in the treated group showed no significant differences in condylar growth post-surgically.

Conclusions

Adolescent patients diagnosed with AICR and anterior disc displacement treated with mandibular ramus and maxillary osteotomies, along with Mitek anchors to reposition internally deranged discs, showed post-surgical normalization of condylar growth.

[Association between craniofacial structures adolescents and temporomandibular disorders]

Objective To determine the association between craniofacial structures and the presence of TMD in adolescents. Material and Methods Cases-control study. 46 patients aged 10 to 16 years old were evaluated with their respective lateral cephalometric X-rays (23 cases and 23 controls matched for age and sex). The TTM was evaluated with the research diagnostic criteria for temporomandibular disorders (RDC/TMD). Results The comparison between cases and controls of the craniofacial structures did not show significant differences, however the lower facial height, facial axis and the mandibular plane were slightly higher in the group of cases. In the two-way analysis of ANOVA (diagnosis and age), facial convexity presented differences between the adolescent with and without temporomandibular disorders (p=0,002). Conclusion Craniofacial structures are not associated with the diagnosis of TMD in adolescents. However, changes occur in relation to the former location of the jaw, resulting in a skeletal pattern class II and an elongated shape of the face.

Orthognathic surgery and temporomandibular joint symptoms

The aim of this article is to review temporomandibular joint symptoms as well as the effects of orthognathic surgery(OGS) on temporomandibular joint(TMJ). The causes of temporomandibular joint disease(TMD) are multifactorial, and the symptoms of TMD manifest as a limited range of motion of mandible, pain in masticatory muscles and TMJ, Joint noise (clicking, popping, or crepitus), myofascial pain, and other functional limitations. Treatment must be started based on the proper diagnosis, and almost symptoms could be subsided by reversible options. Minimally invasive options and open arthroplasty are also available following reversible treatment when indicated.

TMD manifesting in a variety of symptoms, also can apply abnormal stress to mandibular condyles and affect its growth pattern of mandible. Thus, adaptive developmental changes on mandibular condyles and post-developmental degenerative changes of mandibular condyles can create alteration on facial skeleton and occlusion. The changes of facial skeleton in DFD patients following OGS have an impact on TMJ, masticatory musculature, and surrounding soft tissues, and the changes of TMJ symptoms. Maxillofacial surgeons must remind that any surgical procedures involving mandibular osteotomy can directly affect TMJ symptoms, thus pre-existing TMJ symptoms and diagnoses should be considered prior to treatment planning and OGS.

Severe retrognathia as a risk factor for recent onset painful TMJ disorders among adult females

OBJECTIVE

To evaluate the importance of severe retrognathia as a risk factor for the development of recent onset painful TMJ disorders among adult females.

DESIGN

Case-control study.

SETTING

This study was conducted in a large health maintenance organization between 1998 and 1999 [Kaiser Permanente Northwest (KPNW), Portland, OR, USA].

PARTICIPANTS

Adult females with recent onset painful TMJ disorders (n=29) and normal controls (n=104).

METHODS

Cases were recruited from the TMD clinic at Kaiser Permanente Northwest (KPNW). Controls were recruited from a dental clinic at KPNW. Case status was determined using a questionnaire; mandibular sagittal position was determined by measuring a research angle on facial photographs. The mean research angle for cases was compared to the mean for controls. Multivariable exact conditional logistic regression analysis was used to examine the demographic characteristics of cases and controls, and to determine the strength of association between recent onset painful TMJ disorders and severe retrognathia. The population attributable risk percentage (PAR%) and the attributable risk percentage (AR%) were calculated to further evaluate severe retrognathia as a risk factor.

RESULTS

The mean research angle among cases (67.7 degrees; 95% CI=66.0-69.4) was smaller than among controls (71.6 degrees; 95% CI=70.7-72.5, P<0.001). The odds ratio for the association between case status and the presence or absence of severe retrognathia was elevated (OR=6.3; 95% CI=1.1-47.5, P=0.039). The PAR% and AR%, associated with severe retrognathia, were 13.3 and 84.1%, respectively.

CONCLUSIONS

Severe retrognathia is strongly associated with recent onset painful TMJ disorders (OR=6.3). Only a small proportion of these disorders are attributable to severe retrognathia among the total population of adult females (PAR%=13.3%). However, a large proportion of these TMJ disorders are potentially attributable to severe retrognathia among adult females with severe retrognathia (AR%=84.1%).

Role of articular disc in condylar regeneration of the mandible

The articular disc in the temporomandibular joint plays an important role in mandibular growth. Functional appliances induce regeneration of the condyle even after condylectomy. The aim of this study was to examine the role of the articular disc in regeneration of the condyle after unilateral condylectomy with use of a functional appliance in growing rats. Fifty growing rats were subjected to unilateral condylectomy and then half of them underwent discectomy. The functional appliance was applied to half of the rats in each group to induce regeneration of the condyle. Four and eight weeks later, morphometric and histologic analyses of the mandible were performed. Regeneration of the condyle was demonstrated in the two condylectomy groups. In the condylectomy+appliance group, the shape and cartilage of the condyle were equivalent to a normal condyle. However, regeneration of the condyle was not observed in the two discectomy groups even with the use of the functional appliance. The articular disc appears to be crucial in the regeneration of a damaged condyle, suggesting that defects or damage to the articular disc may influence mandibular growth and regeneration or repair of the condyle.

Prevalence of disc displacement of various severities among young preorthodontic population: a magnetic resonance imaging study

PURPOSE

There has been no study on the prevalence of disc displacement (DD) of different levels in children and adolescents with adequate sample size using magnetic resonance images (MRIs). This retrospective cross-sectional study was designed to investigate the relationship between increasing age and the prevalence of DD of various severities in a young preorthodontic population.

MATERIALS AND METHODS

Of 199 preorthodontic patients aged 6 to 15 years visiting a private orthodontic office for initial examination, 153 patients with signs and symptoms of temporomandibular joint (TMJ) disorders had MRIs of their TMJs taken for further evaluation. Of those, 302 TMJs from 151 patients' MRIs of diagnostic quality were divided into three age groups (I: 6 to 9, II: 10 to 12, and III: 13 to 15 years). DD of each patient was categorized based on its severity from stage 0 (normal) to stage 4 (total DD without reduction). The distribution of DD stages in each age group was plotted on a line graph and statistically analyzed for intergroup comparison.

RESULTS

A graphical representation of the results clearly demonstrated a trend for higher occurrence of more advanced DD with an increase in age. No gender difference was observed. Statistical analysis showed that DD was significantly more advanced in group II than group I (p < 0.01) and group III than group I (p < 0.01).

CONCLUSIONS

The study revealed a high prevalence of DD in the young preorthodontic population and significant increase in the proportion of patients with more advanced stages of DD in older patients.

Timing interventions in relation to temporomandibular joint closed lock duration: a systematic review of 'locking duration'

Temporomandibular joint (TMJ) 'closed lock' (CL) is a clinical condition causing TMJ pain and limited mouth opening (painful locking) that is mostly attributed to disc displacement without reduction (DDwoR), or less commonly to anchored disc phenomenon (ADP). Both conditions are described clinically as CL that can be 'acute' or 'chronic' depending on the duration of locking. There is, however, no consensus about the duration of locking that defines the acute state and its effect on the success of interventions. This review paper, therefore, aims to provide: (i) a narrative review of the pathophysiological need for early intervention in DDwoR and the clinical implications of acute/chronic CL stages on the management pathway; (ii) a systematic review investigating the effects of locking duration on the success of interventions for CL management. Electronic and manual searches until mid-August 2013 were conducted for English-language studies of any design investigating the effects of non-surgical and surgical interventions for acute or chronic CL (DDwoR or ADP). A total of 626 records were identified, and 113 studies were included. Data extraction and quality assessment were completed for all included studies. Included studies were, however, heterogeneous and mostly of poor-quality leading to contradictory and inconsistent evidence on the effect of the duration of locking on treatment outcomes. Future high-quality trials investigating the effect of CL duration on treatment outcome are needed. At present, early intervention by 'unlock' mandibular manipulation seems to be the most practical and realistic approach that can be attempted first in every CL patient as an initial diagnostic/therapeutic approach.

Regional 3D superimposition to assess temporomandibular joint condylar morphology

OBJECTIVES

To investigate the reliability of regional three-dimensional registration and superimposition methods for assessment of temporomandibular joint condylar morphology across subjects and longitudinally.

METHODS

The sample consisted of cone beam CT scans of 36 patients. The across-subject comparisons included 12 controls, mean age 41.3 ± 12.0 years, and 12 patients with temporomandibular joint osteoarthritis, mean age 41.3 ± 14.7 years. The individual longitudinal assessments included 12 patients with temporomandibular joint osteoarthritis, mean age 37.8 ± 16.7 years, followed up at pre-operative jaw surgery, immediately after and one-year post-operative. Surface models of all condyles were constructed from the cone beam CT scans. Two previously calibrated observers independently performed all registration methods. A landmark-based approach was used for the registration of across-subject condylar models, and temporomandibular joint osteoarthritis vs control group differences were computed with shape analysis. A voxel-based approach was used for registration of longitudinal scans calculated x, y, z degrees of freedom for translation and rotation. Two-way random intraclass correlation coefficients tested the interobserver reliability.

RESULTS

Statistically significant differences between the control group and the osteoarthritis group were consistently located on the lateral and medial poles for both observers. The interobserver differences were ≤0.2 mm. For individual longitudinal comparisons, the mean interobserver differences were ≤0.6 mm in translation errors and 1.2° in rotation errors, with excellent reliability (intraclass correlation coefficient >0.75).

CONCLUSIONS

Condylar registration for across-subjects and longitudinal assessments is reliable and can be used to quantify subtle bony differences in the three-dimensional condylar morphology.