Post-imaging temporomandibular joint space analysis

The preliminary study of the effects of individual musculoskeletally stable position in the treatment of temporomandibular disorders

BACKGROUND

Temporomandibular Disorders (TMD) is the dysfunction of group of muscles and bones in the joint area, the main symptoms of TMD are the pain of the chewing muscles and (or) the temporomandibular joints, mandibular movement disorders and joint noise. This study was designed to explore the therapeutic effects following Individual Musculoskeletally Stable (IMS) position stabilization splint therapy for TMD patients using Fricton index, cone beam computed tomography (CBCT) and surface-Electromyogram (sEMG).

METHODS

In this study, we enrolled 31 TMD patients (ranging from 18 to 26 years old, including 7 males and 24 females), first Fricton index was used to evaluate the clinical curative effect of TMD with the treatment of IMS stabilization splint; then CBCT was used to observe the TMJ condylar position changes of TMD before and after the treatment of IMS stabilization splint; finally sEMG was used to observe the changes of electromyography of anterior temporalis (AT) and masseter muscles (MM) of TMD before and after the treatment of IMS stabilization splint.

RESULTS

The course of treatment was 6-8 months, with an average of 7.6 months. After the IMS stabilization splint treatment, TMD symptoms relieved, especially in pain, mandibular movement disorder, but still slightly inferior in the treatment of joint noise. And there was a statistically significant difference in the anterior and inner joint space, the condyle had the tendency of moving forward and outward. AT presented reduction significantly of EMG value at rest position after treatment.

CONCLUSIONS

IMS stabilization splint is a therapeutic reversible treatment for TMD, especially for pain and mandibular movement disorder; it produces effects of forward and outward condylar movement and elimination of the masticatory muscles antagonism.

Changes in condylar position and morphology after mandibular reconstruction by vascularized fibular free flap with condyle preservation

OBJECTS

Changes in condylar position and morphology after mandibular reconstruction are important to aesthetic and functional rehabilitation. We evaluated changes in condylar position and morphology at different stages after mandibular reconstruction using vascularized fibular free flap with condyle preservation.

MATERIALS AND METHODS

A total of 23 patients who underwent mandibular reconstruction with fibular flap were included in this retrospective study. CT data of all patients were recorded before surgery (T0), 7 to 14 days after surgery (T1), and at least 6 months after surgery (T2). Five parameters describing the condylar position and 4 parameters describing the morphology were measured in sagittal and coronal views of CT images. The association between clinical characteristics and changes in condylar position and morphology was analyzed. A finite element model was established to investigate the stress distribution and to predict the spatial movement tendency of the condyle after reconstruction surgery.

RESULTS

The condylar position changed over time after mandibular reconstruction. The ipsilateral condyles moved inferiorly after surgery (T0 to T1) and continually move anteriorly, inferiorly, and laterally during long-term follow-up (T1 to T2). Contrary changes were noted in the contralateral condyles with no statistical significance. No morphological changes were detected. The relationship between clinical characteristics and changes in condylar position and morphology was not statistically significant. A consistent result was observed in the finite element analysis.

CONCLUSION

Condylar positions showed obvious changes over time after mandibular reconstruction with condylar preservation. Nevertheless, further studies should be conducted to evaluate the clinical function outcomes and condylar position.

CLINICAL RELEVANCE

These findings can form the basis for the evaluation of short-term and long-term changes in condylar position and morphology among patients who have previously undergone mandibular reconstruction by FFF with condyle preservation.

Clinical Application of Digital Joint Guide in the Fracture of the Condyle Neck

PURPOSE

The purpose of this study is to use a digital guide plate for joint positioning to assist the reduction of condylar neck fractures and evaluate the accuracy of the reduction after surgery.

MATERIALS AND METHODS

In this study, 20 patients were selected from January 2016 to October 2020, and the reduction of the mandibular condyle neck fracture was designed virtual and digital based on the computed tomography data of the patients, based on the position of the condyle in the articular socket, the height of the ascending mandibular ramus, and the joints. The average value of the anterior space and the posterior space of the joint is these indicators, the position of the condyle is reconstructed, and the fracture reduction finger guide plate is designed. During the operation, the digital guide plate is used to assist the reduction of the condyle neck fracture. The postoperative follow-up was 4 to 12 months to check the accuracy of the reduction.

RESULTS

A total of 20 patients, all fractures achieved complete bone healing, the patients' mouth opening was normal, no obvious complications were found, and none of the patients had facial paralysis. In the postoperative evaluation and preoperative virtual design plan, the chromatographic error was within 2 mm, and the magnetic resonance of the temporomandibular joint showed no displacement of the articular disc.

CONCLUSION

The digital joint guide can reduce the fracture of the condyle neck while ensuring the position of the condyle in the joint socket, which is beneficial to reduce the occurrence of subsequent temporomandibular joint complications.

Can Botulinum Toxin-A Contribute to Reconstructing the Physiological Homeostasis of the Masticatory Complex in Short-Faced Patients during Occlusal Therapy? A Prospective Pilot Study

The physiological homeostasis of the masticatory complex in short-faced patients is too robust to be disintegrated and reconstructed due to the powerful masseter muscle. This study innovatively introduced the botulinum toxin-A (BTX-A) into the field of dental occlusal treatment, providing a novel and minimally invasive therapy perspective for the two major clinical problems in these patients (low treatment efficiency and high rates of complications). In total, 10 adult patients with skeletal low angle seeking occlusal treatment (age: 27.0 ± 6.1 years; 4 males and 6 females) were administered 30−50 U of BTX-A in each masseter muscle and evaluated before and 3 months after injection based on cone-beam computed tomography (CBCT). We found a significant reduction in the thickness of the masseter muscle (MMT) (p < 0.0001). With regards to occlusion, we found a significant increase in the height of the maxillary second molar (U7-PP) (p < 0.05) with significantly flattened occlusal curves (the curve of Spee [COS] (p < 0.01), and the curve of Wilson [COW] (p < 0.05)). Furthermore, the variations in the temporomandibular joint exhibited a significant reduction in the anterior joint space (AJS) (p < 0.05) and superior joint space (SJS) (p < 0.05). In addition, the correlation analysis of the masticatory complex provided the basis for the following multiple regression equation: MMT = 10.08 − 0.11 COW + 2.73 AJS. The findings from our pilot study indicate that BTX-A, as a new adjuvant treatment attempt of occlusal therapy for short-faced patients, can provide a more favorable muscular environment for subsequent occlusal therapy through the adjustment of the biting force and may contribute to the reconstruction of healthier homeostasis of the masticatory complex. However, further research is required to establish the reliability and validity of these findings.

Treatment of the mandibular shift in an adult woman and the diagnostic value of joint space index: a case report

Background

Mandibular deviations are common clinical complaints. The orthodontic or orthognathic treatment of mandibular deviations is tricky because a comprehensive diagnosis, especially a functional one, is difficult to make. A inaccurate diagnosis may lead to a compromised and unstable treatment outcome.

Case presentation

This article describes the diagnosis and treatment of a woman with a mandibular deviation and facial skeletal asymmetry. By eliminating the disharmony of the arch form with elastics and bite turbos, her esthetic and functional outcomes improved. Cone-beam CT (CBCT) and Joint Space Index (JSI) analyses served as the diagnostic approaches and outcome evaluation methods before and after treatment.

Conclusions

A condyle position displacement could be an indication of functional deviation. JSI analysis is a quantitative and convenient choice to compare condyle relative positions.

Changes in Condylar Position After Mandibular Reconstruction With Condylar Head Preservation by Computed Tomography

PURPOSE

Condylar position can change after mandibular reconstruction using the free fibula flap. The present study evaluated changes in condylar position using computed tomography (CT) after mandibular reconstruction with condylar head preservation.

MATERIALS AND METHODS

This retrospective study consisted of 16 patients. CT data of 32 temporomandibular joints (TMJs) were recorded before surgery (T0), 7 to 10 days after surgery (T1), and 16.8 ± 7.4 months after surgery (T2). The anteroposterior condylar position was evaluated using the method of Pullinger and Hollender (Oral Surg Oral Med Oral Pathol 62:719, 1986). Repeated-measures analysis of variance (P = .05) was performed.

RESULTS

Data of 16 patients were obtained for statistical analysis. Condylar position changed over time after mandibular reconstruction. The ipsilateral condyles moved anteroinferiorly after surgery (T0 to T1) and tended to move anterosuperiorly during follow-up (T1 to T2). No major changes were noted in the contralateral condyles.

CONCLUSION

Condylar positions showed obvious changes over time after mandibular reconstruction with condylar preservation. Nevertheless, additional studies are warranted to further evaluate the relation between condylar position and TMJ function.

Condylar response to large mandibular advancement combined with maxillary impaction and counterclockwise rotation: A computed tomographic study

Background

This study aims to analyze the effectiveness of cone-beam computed tomography (CBCT) in the evaluation of the condylar position, angulation and intercondylar distance and assess the changes in these parameters before and after bimaxillary surgery, preformed with the critical movments of Le Fort I osteotomy (for impaction of the maxilla and conterclockwise rotation of the upper occlusal plane) and Bilateral Sagittal Split Osteotomy (BSSO) for mandibular advancement (> 8mm).

Material and Methods

Twenty class II patients successfully treated with BSSO of the mandible, in conjunction with Le Fort I osteotomy, were studied to evaluate the condylar changes before and after surgery. The position of the condyle was classified according to the Pullinger & Hollender’s formula in both phases. A MANOVA analysis followed by post-hoc tests were conducted to ascertain if there were statistically significant differences between pre and post surgical variables under study. The agreement of the condylar position’s classification was evaluated resorting to the Kappa statistics.

Results

There were no statistically significant differences between the values of the position and angulation of the condyles and intercondylar distance before and after surgery. There was an increase of the axial angle of the left condyle and the frontal angle of both condyles, while there was a decrease of the axial angle of the right condyle, the sagittal angle of both condyles and intercondylar distance.

Conclusions

The CBCT is a useful method for assessing variations of condylar position in detail. It was verified that the critical movements of maxillary impaction associated with the mandibular advancement do not produce significant alterations in the mandibular condyles, however, these tend to perform a posterior and inferior movement.

Key words:Cone-Beam computed tomography, orthognathic surgery, mandibular condyle, osteotomy, le fort, temporomandibular joint.

Mandibular condylar morphology for bruxers with different grinding patterns

OBJECTIVES

The purpose of this study was to investigate the mandibular condylar morphology for bruxers with different grinding patterns.

METHOD

Condylar sectional morphology and condylar position of 30 subjects were determined by two viewers using cone beam computed tomography (CBCT) image data sets. The grinding patterns during sleep bruxism (SB) were determined objectively using a Brux-checker device.Chi-square tests were used for statistical analysis for the condylar morphology type between different tooth grinding patterns. Spearman's rank correlation coefficient was used for correlation analysis between condylar position and the canine guidance area during SB.

RESULTS

Theincidence of condylarmorphologicaldivergence from idealwas35%.There isa significant difference in distribution of condylar morphology type between the group grinding (GG) and GG combined with mediotrusive side grinding (MG) (p < 0.05). There was no significant correlation between condylar position and canine guidance area during bruxism.

DISCUSSION

MG during SB is associated with condylar morphology that is considered not to be ideal.

Cone-Beam Computed Tomography Assessment of Lower Facial Asymmetry in Unilateral Cleft Lip and Palate and Non-Cleft Patients with Class III Skeletal Relationship

Introduction

To evaluate, using cone-beam computed tomography (CBCT), both the condylar-fossa relationships and the mandibular and condylar asymmetries between unilateral cleft lip and palate (UCLP) patients and non-cleft patients with class III skeletal relationship, and to investigate the factors of asymmetry contributing to chin deviation.

Methods

The UCLP and non-cleft groups consisted of 30 and 40 subjects, respectively, in mixed dentition with class III skeletal relationships. Condylar-fossa relationships and the dimensional and positional asymmetries of the condyles and mandibles were examined using CBCT. Intra-group differences were compared between two sides in both groups using a paired t-test. Furthermore, correlations between each measurement and chin deviation were assessed.

Results

It was observed that 90% of UCLP and 67.5% of non-cleft subjects had both condyles centered, and no significant asymmetry was found. The axial angle and the condylar center distances to the midsagittal plane were significantly greater on the cleft side than on the non-cleft side (P=0.001 and P=0.028, respectively) and were positively correlated with chin deviation in the UCLP group. Except for a larger gonial angle on the cleft side, the two groups presented with consistent asymmetries showing shorter mandibular bodies and total mandibular lengths on the cleft (deviated) side. The average chin deviation was 1.63 mm to the cleft side, and the average absolute chin deviation was significantly greater in the UCLP group than in the non-cleft group (P=0.037).

Conclusion

Compared with non-cleft subjects with similar class III skeletal relationships, the subjects with UCLP showed more severe lower facial asymmetry. The subjects with UCLP presented with more asymmetrical positions and rotations of the condyles on axial slices, which were positively correlated with chin deviation.

Analysis of the condyle/fossa relationship before and after prosthetic rehabilitation with maxillary complete denture and mandibular removable partial denture

STATEMENT OF PROBLEM

The influence of the loss of posterior teeth on the condylar position and on temporomandibular disorders (TMDs) remains a controversial issue.

PURPOSE

This study investigated whether prosthetic rehabilitation promoted modification of the condylar position in subjects without symptoms of TMDs.

MATERIAL AND METHODS

The temporomandibular joints (TMJs) of 12 women (age 37 to 74), all with existing maxillary complete dentures but no removable partial denture (RPD) restoring the Kennedy class I partially edentulous mandibular arch and no clinical signs of TMDs according to the criteria established by Helkimo, were viewed in maximal intercuspal position with corrected lateral tomography before and after prosthetic rehabilitation with a new maxillary complete denture and a mandibular RPD. Before prosthetic rehabilitation, a mandibular stabilizing base was fabricated to prevent the existing maxillary complete denture from dislodging during tomographic examination. Two methods were used to evaluate tomograms: (1) linear measurements of the subjective narrowest anterior and posterior intra-articular joint spaces made from the tomograms by use of a digital caliper and (2) linear measurements of the anterior and posterior intra-articular joint spaces on the basis of drawings and tracings. Repeated-measures analysis of variance followed by orthogonal contrasts were used to evaluate differences between measurements carried out on the same subject under the different test conditions of the study (before prosthetic rehabilitation, before prosthetic rehabilitation with a mandibular stabilizing base in position, and after prosthetic rehabilitation) (P<.05).

RESULTS

Before prosthetic rehabilitation, a predominance of posterior condylar positions was observed. Before prosthetic rehabilitation with a mandibular stabilizing base in position, a significant decrease was observed in posterior condylar positions (P=.03). This decrease was more marked after prosthetic rehabilitation (P=.02). The subjective evaluation and comparison on the basis of drawings and tracings used to analyze the tomograms produced similar results (P=.70).

CONCLUSION

Within the limitations of this study, significant changes in the condylar position occurred after prosthetic rehabilitation in subjects without symptoms of TMDs.

Effect of Herbst treatment on temporomandibular joint morphology: a systematic literature review

The purpose of this systematic review was to evaluate the effect of Herbst appliance therapy on temporomandibular joint (TMJ) morphology, with special reference to glenoid fossa remodeling, condylar remodeling, condylar position, and articular disc position. Publications of controlled trials of Herbst treatment of Class II patients using magnetic resonance imaging (MRI), computerized tomography scans, or tomography to assess TMJ morphology were identified with Medline (1966-2001), Best Evidence (1991-2001), Cochrane Database of Systematic Reviews (second quarter, 2001), and Embase (1998-2001). Case reports were excluded. Based on our search, only 5 studies met the selection criteria. All studies used internal controls with pretreatment and posttreatment imaging. Four studies used MRI, and 1 used tomograms. The 4 MRI studies used overlapping patient samples and were not considered as independent evidence. The MRI studies did not provide conclusive evidence of osseous remodeling or condyle position change. The tomography study demonstrated minor condyle position change. Methodological deficiencies prevented major conclusions regarding disc position. The reviewed studies highlight the importance of further research. Prospective controlled studies using serial MRI and tomography are required to establish the effect of Herbst treatment on TMJ morphology.

A method for integrating facial cephalometry and corrected lateral tomography of the temporomandibular joint

OBJECTIVES

To test the validity of an indirect method for obtaining the Frankfort horizontal (FH) plane and transferring it from the originating cephalogram to a tomogram.

METHODS

One hundred and fifty-two corrected lateral tomograms from 38 individuals, taken before and after treatment, were used for this study. The tomograms were scanned and digitized. The angle between the FH plane and the long axis of the pterygopalatine fossa was measured on the reciprocal cephalograms. In addition, a tangent was drawn at the uppermost point of the glenoid fossa and parallel to the upper border of the film. Common variables regarding these two planes were measured and compared.

RESULTS

It was found that the tangent to the fossa roof, parallel to the superior border of the film, did not coincide with the transferred cephalometric FH plane. Statistically significant differences were found between all variables for the two groups.

CONCLUSIONS

In cases where integration of cephalometric and tomographic measurements are needed, the drawing of a tangent on the roof of the fossa is not a reliable method.