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

Physical therapy and non-surgical manual disc reduction combined with anterior repositioning splint for acute disc displacement without reduction of the temporomandibular joint in adolescents

OBJECTIVES

Current studies on the treatment of adolescent patients with disc displacement without reduction (DDWOR) are limited by short follow-up periods and small sample sizes, and there are few comparative studies on the efficacy of conservative treatment with and without disc reduction for acute DDWOR. This study compared the therapeutic effects of two conservative treatment methods: physical therapy alone and physical therapy combined with non-surgical manual disc reduction and anterior repositioning splints (ARS), in adolescent patients with acute DDWOR.

MATERIALS AND METHODS

This retrospective study included adolescent patients with DDWOR who underwent physical therapy at the Temporomandibular Joint Rehabilitation Department of the Shanghai Ninth People's Hospital from January 2018 to December 2021. Patient assessment data were collected before and after treatment. Patients were followed up through telephone and online questionnaires from March to August 2023.

RESULTS

The results indicate that compared to physical therapy alone, the combination of physical therapy and non-surgical manual disc reduction with ARS showed better short-term efficacy, improved mouth opening, and better long-term pain control. Also, it may be effective in preventing degenerative joint disease.

CONCLUSIONS

This combination therapy is recommended for clinical application in adolescent patients with acute DDWOR.

CLINICAL RELEVANCE

The present research demonstrates the superior efficacy of physical therapy and non-surgical manual disc reduction combined with anterior repositioning splint in adolescent patients with acute DDWOR.

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.

Observational study investigating the relationship between maxillomandibular characteristics and temporomandibular disc conditions in female patients with a skeletal class III pattern

OBJECTIVES

The objective of this study was to analyze the relationship between maxillomandibular characteristics and the severity of temporomandibular disc displacement in female patients with a skeletal class III (SKIII) pattern.

METHODS

Fifty-seven samples were included in the study. The evaluation of articular disc conditions was conducted using magnetic resonance imaging, while 25 cephalometric variables from lateral and postero-anterior (P-A) cephalograms were measured to determine their maxillomandibular characteristics. The samples were categorized into three groups based on the articular disc conditions: (1) normal disc position (NDP), (2) disc displacement with reduction (DDwR), and (3) disc displacement without reduction (DDwoR). The relationship between the maxillomandibular characteristics and disc conditions was examined through both basic statistical analysis and multivariate analysis using principal component analysis (PCA).

RESULTS

The Kruskal-Wallis and Dunn-Bonferroni tests revealed a significant difference between the groups in terms of the deviation of mandibular characteristics observed on the P-A cephalogram. The DDwoR group exhibited significantly larger menton deviation, ramal height asymmetry index, and total mandibular length asymmetry index compared to the NDP and DDwR groups. Moreover, the PCA successfully extracted all cephalometric variables into eight principal components. Among them, only the principal component related to mandibular asymmetry was able to differentiate the SKIII samples with DDwoR from the other groups.

CONCLUSIONS

The findings of this study highlight a significant relationship between mandibular asymmetry and the severity of disc displacement, particularly DDwoR, in female patients with a SKIII pattern.

Divergent chondro/osteogenic transduction laws of fibrocartilage stem cell drive temporomandibular joint osteoarthritis in growing mice

The anterior disc displacement (ADD) leads to temporomandibular joint osteoarthritis (TMJOA) and mandibular growth retardation in adolescents. To investigate the potential functional role of fibrocartilage stem cells (FCSCs) during the process, a surgical ADD-TMJOA mouse model was established. From 1 week after model generation, ADD mice exhibited aggravated mandibular growth retardation with osteoarthritis (OA)-like joint cartilage degeneration, manifesting with impaired chondrogenic differentiation and loss of subchondral bone homeostasis. Lineage tracing using Gli1-CreER+; Tmfl/-mice and Sox9-CreER+;Tmfl/-mice showed that ADD interfered with the chondrogenic capacity of Gli1+ FCSCs as well as osteogenic differentiation of Sox9+ lineage, mainly in the middle zone of TMJ cartilage. Then, a surgically induced disc reposition (DR) mouse model was generated. The inhibited FCSCs capacity was significantly alleviated by DR treatment in ADD mice. And both the ADD mice and adolescent ADD patients had significantly relieved OA phenotype and improved condylar growth after DR treatment. In conclusion, ADD-TMJOA leads to impaired chondrogenic progenitor capacity and osteogenesis differentiation of FCSCs lineage, resulting in cartilage degeneration and loss of subchondral bone homeostasis, finally causing TMJ growth retardation. DR at an early stage could significantly alleviate cartilage degeneration and restore TMJ cartilage growth potential.

Malocclusion Complexity in Patients with Disc Displacement Disorders: A Case-Control Study

This study aimed to determine the possible association between disc displacement (DD) disorders and malocclusion complexity. This cross-sectional study was carried out using a case-control design. The Research Diagnosis Criteria for Temporomandibular Disorders were used to identify cases and controls. The Index of Complexity, Outcome, and Need (ICON) was used to quantify malocclusion complexity as easy, mild, moderate, difficult, or very difficult. A total of 310 subjects were included: 130 cases and 180 controls. A binary logistic regression (p < 0.05) was used to identify associations. The odds ratio (OR) was also calculated. DD was associated with sex, age, and malocclusion complexity (p < 0.05). The malocclusion complexity comparison showed that 89.3% of the controls fell within the easy-moderate levels of the ICON, whereas 85.4% of the cases were in the moderate-very difficult levels (p ≤ 0.001). Difficult and very difficult malocclusions had high ORs (9.801 and 9.689, respectively) compared to the easy cases. In conclusion, patients with malocclusion complexity levels classified as difficult or very difficult have greater odds of presenting DD.

Concomitant Temporomandibular Joint Replacement and Orthognathic Surgery

The treatment of patients with severe temporomandibular joint (TMJ) disorders and associated skeletal discrepancies presents a complex challenge for oral and maxillofacial surgeons. It is widely recognized that TMDs can impact the stability and outcomes of surgical treatments for dentofacial deformities. Consequently, addressing TMDs prior to or in conjunction with orthodontic or surgical interventions may be necessary to achieve optimal and long-lasting results. Alloplastic temporomandibular joint replacement (TMJR) and orthognathic surgery have emerged as the standard approach due to their predictability, long-term stability and excellent outcomes when addressing end-stage TMJ disease in conjunction with DFDs as it provides a comprehensive solution to address both functional and aesthetic aspects of these patients' conditions. Understanding the appropriate utilization of TMJR in conjunction with orthognathic surgery can lead to improved treatment planning and successful outcomes for patients with complex TMJ disorders and associated dentofacial deformities. This review aims to discuss the indications, preoperative evaluation, staging, sequencing, and surgical considerations involved in utilizing alloplastic TMJ replacement in the presence of dentofacial deformities.

Treatment of severe open bite and mandibular condyle anterior displacement by mini-screws and four second molars extraction: A case report

BACKGROUND

Temporomandibular joint (TMJ) disorders are closely related to high-angle and skeletal Class II malocclusion. Sometimes pathological changes in the mandibular condyle can cause open bite to occur after growth is complete.

CASE SUMMARY

This article is about the treatment of an adult male patient with a severe hyperdivergent skeletal Class II base, an unusual and gradually occurring open bite and an abnormal mandibular condyle anterior displacement. Because the patient refused surgery, four second molars with cavities and root canal therapy were extracted, and four mini-screws were used for intrusion of the posterior teeth. The treatment duration was 22 mo, and after the treatment, the open bite was corrected and the displaced mandibular condyles were seated back to the articular fossa as shown by cone-beam computed tomography (CBCT). Based on the patient’s open bite history, the result of clinical examinations and CBCT comparisons, we believe it is possible that the occlusion interference was eliminated after the four second molars were extracted and the posterior teeth were intruded, and the patient's condyle spontaneously returned to its physiologic position. Finally, a normal overbite was established, and stable occlusion was achieved.

CONCLUSION

This case report suggested that identifying the cause of open bite is essential, and the TMJ factors for hyperdivergent skeletal Class II cases should be particularly examined. For these cases, intruding posterior teeth may place the condyle in a more appropriate position and provide an environment suitable for TMJ recovery.

Changes in the condylar volume and skeletal relapse following orthognathic surgery in patients with dentofacial deformity: A retrospective study

OBJECTIVE

To evaluate the relationship between the changes in condylar volume and maxillofacial skeletal morphology according to sex as well as the relationship between condylar volume reduction and skeletal relapse in patients who underwent orthognathic surgery.

METHODS

Ninety-five patients were categorized into skeletal Class III, Class II, and facial asymmetry groups. Computed tomography scans taken preoperatively and at 1 year postoperatively were used for quantitative measurement.

RESULTS

Postoperative condylar volume was reduced in both the Class II group and the deviated side of the asymmetry group. Both female and Class II deformity were significant predictors of postoperative reduction in the condylar volume. There was a significant correlation between skeletal relapse and postoperative change in condylar volume in the Class II group.

CONCLUSION

Postoperative condylar resorption may be associated with preoperative maxillofacial skeletal morphology and sex and also with skeletal relapse in the Class II group.

Mandibular asymmetry as a possible etiopathologic factor in temporomandibular disorder: a prospective cohort of 134 patients

OBJECTIVES

The present study aimed to investigate mandibular asymmetry as a possible etiopathologic factor in temporomandibular disorder (TMD).

MATERIALS AND METHODS

A prospective cross-sectional study of patients with dentofacial deformities seeking corrective orthognathic surgery was conducted. The pre-operative prevalence of TMD in patients with mandibular asymmetry and other dentofacial deformities was assessed using the Diagnostic Criteria for TMD (DC/TMD) Axis I protocol.

RESULTS

A total of 134 patients were recruited - 82 with mandibular asymmetry and 52 without. There was a significantly higher prevalence of TMD in those with mandibular asymmetry (67.1%; 95% CI 59 to 75%) compared to those without (40.4%; 95% CI 32 to 49%, p = 0.002). The overall pre-operative prevalence of TMD in this population of patients was 56.7% (95% CI 48 to 65%). Pain disorder only was present in 9.7%, TMJ disorder only in 29.9%, and both pain and TMJ disorders in 17.2%. The most prevalent type of TMD is disc displacement with reduction (77.6%), followed by myalgia (35.5%) and arthralgia (21.1%).

CONCLUSION

The prevalence of TMD in those with mandibular asymmetry was significantly higher than those without, suggesting that mandibular asymmetry could be a possible etiopathologic factor in TMD.

CLINICAL RELEVANCE

The significantly higher prevalence of temporomandibular disorder in those with mandibular asymmetry suggests that we need to be especially cognizant of this condition in our pre-operative, surgical, and post-operative management of this group of orthognathic patients.

An Overview of the Post-Traumatic Mandibular Bifid Condyle

Objectives: To review the main clinical, radiological and treatment aspects of patients with post-traumatic bifid mandibular condyles (BMC), to report a new case of BMC in a patient with history of trauma and to discuss the long term adaptive changes of the opposite condylar head. Methods: An electronic search in major medical databases was accomplished. Case series and case reports, prospective or retrospective cohort studies of patients with characteristics of traumatic BMC were included. Extracted data included demographic variables, clinical aspects, imagining examinations and treatment methods performed. Results: The systematic review included 60 patients with 72 post-traumatic BMC. The unilateral involvement (73.3%) and mediolateral condylar orientation (75%) were the most common types of post-traumatic BMC described. Most of the patients were symptomatic, with ankylosis (60%), limitation in mandibular movements (55%) and facial asymmetry (41.6%) being the most common clinical signs. Conclusion: The presence of the post-traumatic BMC is accompanied by important clinical signs, a correct and an early evaluation being essential for an optimal treatment.

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.

The Mandible is Further Retruded Under General Anesthesia: The Latent Concept for a Favorable Outcome in Sagittal Split Ramus Osteotomy

Introduction

In orthognathic surgery, we often experience that model mounting by the occlusal bite record taken at centric relation under the conscious condition in the sitting position does not always correctly replicate the actual maxilla-mandibular relationship under general anesthesia. Mandible often moves backward further in the latter condition. The present study was carried out to investigate the degree of extra retrusion of the mandible under general anesthesia and to determine the characteristics in each of the three original skeletal class patterns in a Japanese population.

Patients and methods

Fifty patients with jaw deformities (14 males and 36 females) were enrolled in this prospective study, their ages ranging from 16 to 49 years. The occlusal bite record at the incisor region obtained from a mounted articulator was compared with the records from the oral cavity of the patient under general anesthesia before surgery.

Results

Retrusion in the supine position under general anesthesia was observed in all skeletal classes, and it was significantly greater in skeletal Class II, compared to skeletal Class I and Class III.

Conclusion

This study clearly revealed the difference among three different skeletal classes, and the mandible in the skeletal Class II moved backward significantly compared to other classes.