The "anchored disc phenomenon": a proposed etiology for sudden-onset, severe, and persistent closed lock of the temporomandibular joint

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.

Biomechanics and Derangements of the Temporomandibular Joint

The human temporomandibular joint, is a ginglymo-arthrodial joint. The articular disk serves as a fibrous, viscoelastic structure that allows force distribution and smooth movement of the joint in its normal arrangement during mandibular movements. Most studies suggest that in the normal disk position the posterior band is located at the 12'o clock position within the glenoid fossa in the closed mouth posture. When the biomechanics of the joint is altered, the disk may be displaced creating an abnormal relationship between the disk, condyle, and the eminence that is often referred to as an internal derangement. This article reviews the various presentations of internal derangements.

Athrocentesis: What, When, and Why?

The introduction of temporomandibular joint (TMJ) arthroscopy by Onishi in 1970 (results published in 1975 and 1980) opened a new modality for TMJ treatment. The efficiency of arthroscopic lavage and lysis led in the 1990s to its simplification: TMJ arthrocentesis. Always associated with load control, physiotherapy, and elimination of any occlusal hazards, arthrocentesis, a simple procedure, entails less expensive and more available tools and is performed under local anesthesia. Although lacking direct visual inspection of the joint structures, it has become quite popular. Arthrocentesis is most efficient in localized joint pain and limited joint movements such as closed lock, anchored disc phenomenon, osteoarthritis, and various inflammatory diseases. In clicking joint, the results are somewhat controversial. The efficiency of arthrocentesis elicited many enquiries that led to the study and a better understanding of joint function and dysfunction and the actual role of disc location. The release of closed lock without disc repositioning was quite surprising; it improved our understanding of the pathogenesis of closed lock and led to the discovery of the anchored disc phenomenon. This was followed by the awareness of the joint-lubrication system and, in turn, alternative suggestions for the pathogenesis of TMJ disc displacement with and without reduction, open lock, and osteoarthritis, and ultimately by the development of an effective bio-lubricant. Awareness of the role of joint overloading led to the development of an interocclusal appliance that reduces intraarticular pressure; it has become a "must" support for arthrocentesis and any surgical intervention. In our view, arthrocentesis is the definitive indication of the need for surgical intervention and, therefore, should be the first in the cascade of interventions in TMJ disorders.

General Characteristics, Biomedical and Dental Application, and Usage of Chitosan in the Treatment of Temporomandibular Joint Disorders: A Narrative Review

The aim of this narrative review was to present research investigating chitosan, including its general characteristics, properties, and medical and dental applications, and finally to present the current state of knowledge regarding the efficacy of chitosan in the treatment of temporomandibular disorders (TMDs) based on the literature. The PICO approach was used for the literature search strategy. The PubMed database was analyzed with the following keywords: (“chitosan”[MeSH Terms] OR “chitosan”[All Fields] OR “chitosans”[All Fields] OR “chitosan s”[All Fields] OR “chitosane”[All Fields]) AND (“temporomandibular joint”[MeSH Terms] OR (“tem-poromandibular”[All Fields] AND “joint”[All Fields]) OR “temporomandibular joint”[All Fields] OR (“temporomandibular”[All Fields] AND “joints”[All Fields]) OR “temporo-mandibular joints”[All Fields]). After screening 8 results, 5 studies were included in this review. Chitosan presents many biological properties and therefore it can be widely used in several branches of medicine and dentistry. Chitosan promotes wound healing, helps to control bleeding, and is used in wound dressings, such as sutures and artificial skin. Apart from its antibacterial property, chitosan has many other properties, such as antifungal, mucoadhesive, anti-inflammatory, analgesic, antioxidant, antihyperglycemic, and antitumoral properties. Further clinical studies assessing the efficacy of chitosan in the treatment of TMD are required. According to only one clinical study, chitosan was effective in the treatment of TMD; however, better clinical results were obtained with platelet-rich plasma.

An International Survey on Temporomandibular Joint Surgeon's Implementation and Management of Discectomy in Treating Temporomandibular Joint Internal Derangement

PURPOSE

To survey temporomandibular joint (TMJ) surgeons to determine current practice trends and perceptions regarding the role of discectomy for the treatment of TMJ internal derangements.

METHODS

An anonymous 5-part web-based survey was sent to TMJ surgeons. The survey was created and distributed, and the data were collected with the University of Michigan Qualtrics platform. Responses were compared based on operative volume, tendency to replace the disc, and likelihood of requiring temporomandibular joint replacement (TJR) after discectomy. Spearman correlations were used to test statistically significant differences. Domain-level analyses were also performed by summarizing items into 3 domain scores. Analyses were performed in SAS V9.4 (SAS Institute Inc., Cary, NC, USA).

RESULTS

Fifty-nine surgeons (33.9%) completed the survey. Discectomy was not considered to be a useful procedure by 85% of respondents, and 74% would not consider discectomy as a first surgical option. Most would consider discectomy (64%) before alloplastic total joint replacement. Discectomy was preferred over discopexy for the management of anterior disc displacement with reduction by high volume surgeons (89%), but most (72%) did not feel that discectomy was beneficial over arthroscopy in the treatment of anterior disc displacement without reduction and concomitant degenerative bony changes. In managing symptomatic disc perforation, 66% agreed that discectomy is the procedure of choice and 49% felt that interpositional tissue is indicated in most cases after discectomy. Respondents who reported fewer re-operations requiring alloplastic TJR after discectomy had, on average, more positive perceptions of discectomy on the benefits domain (P = .03), better than alternatives domain (P = .03), and fewer concerns on the perceived adverse effects domain (P = .03).

CONCLUSIONS

TMJ surgeons do not employ TMJ discectomy in most cases of TMJ internal derangement. However, discectomy is considered useful in cases of disc perforation or for persistent symptomatic disc displacement without reduction, in an attempt to avoid alloplastic TJR. Common adverse effects included joint noises and osteoarthrosis, and the use of interpositional disc replacement tissue did not alter the incidence of adverse effects or complications reported.

Application of auriculotemporal nerve block and dextrose prolotherapy in exercise therapy of TMJ closed lock in adolescents and young adults

Background

Temporomandibular joint (TMJ) ‘closed lock’ is a clinical condition causing TMJ pain and limited mouth opening (painful locking). Recent studies suggest an increasing prevalence of degenerative joint disease associated with the onset of TMJ closed lock in adolescents and young adults. Early interventions are recommended, but the curative effect of standard therapies remains controversial. In this retrospective study, an alternative method of non-surgical treatment of TMJ closed lock is presented, and its long-term efficacy has been observed.

Methods

Forty adolescents and young adults, aged 16 to 30 years old, with distinct combination of symptoms of TMJ closed lock, were enrolled. Patients received anesthetic blockages of the auriculotemporal nerve, then performed mandibular condylar movement exercise for 10 min, and subsequently received hypertonic dextrose prolotherapy in retro-discal area of TMJ. Clinical assessments at baseline and at follow-up (2 weeks, 2 months, 6 months, and 5 years) included intensity and frequency of TMJ pain, mandibular range of motion, TMJ sounds, and impairment of chewing.

Results

Cone beam CT images of the TMJs revealed joint space changes in all patients and degenerative bone changes in 20% (8/40) of the patients. The patients were diagnosed as having disc displacement without reduction with limited opening. Successful reduction of displaced disc had been achieved in the treatment. And pain at rest and pain on mastication had substantially decreased in all patients and mandibular function and mouth opening had significantly improved since 2 weeks’ follow-up. The overall success rate kept at a high level of 97.5% (39/40) at 6 months and 5 years’ follow-up.

Conclusions

The technique combining mandibular condylar movement exercise with auriculotemporal nerve block and dextrose prolotherapy is straightforward to perform, inexpensive and satisfactory to young patients with TMJ closed lock.

Does Repositioning of Temporomandibular Joint Disc With Bone Anchors Provide Better Clinical Outcomes Than Conventional Disc Plication Procedures for Anterior Disc Displacements Without Reduction in Patients Refractory to Nonsurgical Treatments?

PURPOSE

Although open temporomandibular joint arthroplasty with discopexy is a common treatment for patients with anterior disc displacements without reduction (ADDWo) unresponsive to medical management, there are no studies comparing disc repositioning with bone anchors and conventional discopexy procedure. The purpose of the study was to compare the efficacy between disc repositioning with bone anchors and the conventional discopexy procedure for ADDWo of temporomandibular joint refractory to medical management.

PATIENTS AND METHODS

A randomized controlled trial was conducted in patients with ADDWo. The primary objective was to compare the improvement in mouth opening (primary outcome variable) between the 2 treatment (primary predictor variable) groups-disc repositioning with bone anchors versus conventional disc plication. Secondary outcome variables were pain measured by visual analog scale, lateral excursions, and position of the disc evaluated by magnetic resonance imaging (MRI). Other variables of interest were age, gender, and duration of symptoms. The parameters were evaluated at preoperative, postoperative day 1, and 1-, 6-, and 12-month postoperative period. Categorical variables were compared with χ² test and continuous variables with analysis of variance and adjusted for multiple comparisons with Bonferroni test.

RESULTS

The study sample comprised 14 patients (7 in each group) with MRI-proven ADDWo. Statistically significant differences were found in the improvement of mouth opening between the 2 groups, showing better improvement with bone anchors (14.42 ± 5.96 vs 7.57 ± 7.25 mm; P < .05). The reduction in visual analog scale also showed statistically significant difference with better pain reduction achieved with bone anchor (4.57 ± 1.61 vs 3.28 ± 0.75; P < .05). There was no statistically significant difference in lateral excursions and postoperative position of the disc evaluated by MRI between the groups at the 12-month follow-up period.

CONCLUSIONS

Disc repositioning with bone anchors provides better clinical outcomes in terms of maximal mouth opening and pain scores compared with conventional disc plication.

Is the Anchored Disc Phenomenon a Truly Distinct Entity? A Systematic Review

PURPOSE

This review aimed to examine whether the anchored disc phenomenon (ADP) is truly a distinct entity, independent of the closed-lock condition attributed to nonreducible disc displacement.

MATERIALS AND METHODS

Clinical and/or diagnostic imaging studies addressing the anchored disc or ADP were considered. Articles eligible for inclusion were written in English; were conducted in humans; showed, in their titles or abstracts, any of the keywords used in the search method; included some type of disc imaging system; and related disc mobility to disc position. Of 18 potentially relevant articles, 10 were included.

RESULTS

Of the studies, 9 used magnetic resonance imaging and 1 used double-contrast cone-beam computed tomography. In 1,691 joints, 270 discs (16%) were shown to be anchored in a normal (41%) or displaced (59%) position. Of 149 displaced anchored discs, 52 were reducible and 97 were nonreducible. Intra-articular adherences, synovitis, and adhesions were common arthroscopic findings in patients with the ADP.

CONCLUSIONS

The temporomandibular joint anchored disc shown by disc imaging systems is worthy of inclusion in the existing categories of temporomandibular joint internal derangement. Classification of the ADP as a distinct entity still awaits a consensual definition of the problem, validation of the underlying hypothesis, and clarification of the natural history of the phenomenon.

Clinical protocol for occlusal adjustment: Rationale and application

BACKGROUND

Occlusal adjustment can optimize the result of orthodontics, orthognathic surgery, and comprehensive restoration, and resolve adverse forces to the dentition that affect the entire masticatory system. Mounted diagnostic casts and computerized occlusal analysis offer complementary advantages for evaluating occlusal problems. Predictable occlusal adjustment is facilitated by precise, measured documentation of occlusal force by computerized occlusal analysis.

CLINICAL PRESENTATION

A conservative, structural correction of a pronounced, chronic occlusal problem by additive and subtractive occlusal adjustment was performed after a previous failed occlusal adjustment. The patient's chief concerns were significant anterior teeth fremitus in maximum intercuspation and "pain in the teeth and a poor bite" after 30+ adjustments over 2.5 years.

CLINICAL RELEVANCE

Confirmation of specific criteria for a therapeutic occlusion resolved the anterior teeth fremitus and uneven bite. Traumatic occlusal contact on posterior teeth may elicit protective mandibular repositioning affecting anterior teeth relationships and should be considered during comprehensive diagnosis.

Limited mouth opening of unknown cause cured by diagnostic coronoidectomy: a new clinical entity?

Limited mouth opening is a constant annoyance and can be life-threatening should intubation be needed. The causes are numerous and are categorised as intra-articular or extra-articular, which are often difficult to distinguish. We present what we regard as a new clinical entity - long-standing limited mouth opening of unknown cause - and describe our treatment. Four female patients presented with limited mouth opening and lateral and protrusive movements within normal limits, which were typical of restriction of extra-articular origin. However, the radiological findings were within normal limits, with no visible cause of the restriction. All four were treated by bilateral coronoidectomy that resulted in the immediate return of mouth opening to within normal limits that was preserved over subsequent years. Histopathological examination showed atrophy and degenerative changes in the temporalis band that had been attached to the coronoid, which accounts for the stiffness of the temporalis muscle but does not explain the pathogenesis. In the light of this "diagnostic coronoidectomy" further studies are required to document the underlying pathological changes and to develop more accurate imaging that will enable correct diagnosis in future.

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.

Expanding the taxonomy of the diagnostic criteria for temporomandibular disorders

There is a need to expand the current temporomandibular disorders' (TMDs) classification to include less common but clinically important disorders. The immediate aim was to develop a consensus-based classification system and associated diagnostic criteria that have clinical and research utility for less common TMDs. The long-term aim was to establish a foundation, vis-à-vis this classification system, that will stimulate data collection, validity testing and further criteria refinement. A working group [members of the International RDC/TMD Consortium Network of the International Association for Dental Research (IADR), members of the Orofacial Pain Special Interest Group (SIG) of the International Association for the Study of Pain (IASP), and members from other professional societies] reviewed disorders for inclusion based on clinical significance, the availability of plausible diagnostic criteria and the ability to operationalise and study the criteria. The disorders were derived from the literature when possible and based on expert opinion as necessary. The expanded TMDs taxonomy was presented for feedback at international meetings. Of 56 disorders considered, 37 were included in the expanded taxonomy and were placed into the following four categories: temporomandibular joint disorders, masticatory muscle disorders, headache disorders and disorders affecting associated structures. Those excluded were extremely uncommon, lacking operationalised diagnostic criteria, not clearly related to TMDs, or not sufficiently distinct from disorders already included within the taxonomy. The expanded TMDs taxonomy offers an integrated approach to clinical diagnosis and provides a framework for further research to operationalise and test the proposed taxonomy and diagnostic criteria.

Prognostic factor of mandibular condylar movement exercise for patients with internal derangement of the temporomandibular joint on initial presentation: preliminary report

PURPOSE

The aim of this study is to examine the factors, which predict the effect of mandibular condylar movement exercise (MCME).

MATERIAL AND METHODS

We investigated the efficiency of MCME and the significant difference in average age and the mean duration length of closed lock symptoms prior to the initial consultation in both success cases and failure cases in initial visiting. Seventy-four women aged between 19 and 75 (mean: 41.4) years were included in this study.

RESULTS

On the initial visiting day, the success cases were 50 cases (67.6%) and the failures were 24 cases (23.4%). The average age of success cases is 38.0 years, and failure cases are 48.4 years. Duration of the lock in success cases is 35.3 days, and failure cases are 87.6 days.

CONCLUSION

These results suggested that lower improvement rates thus correlated with increasing age with exercise. MCME is effective mouth-opening exercise in patients with a history of short duration of locking. In conclusion, age and duration of locking, it must become the important factor predict an effect MCME.

Total antioxidant capacity and total oxidant status of synovial fluids in patients with temporomandibular joint pain and dysfunction

OBJECTIVES

The objective of this study was to investigate whether a relationship exists between total antioxidant capacity (TAC) and total oxidant status (TOS) of synovial fluids (SFs) of temporomandibular joint (TMJ) pain patients with pain and dysfunction.

MATERIALS AND METHODS

Forty-two patients with TMJ pain were included in this study. TAC and TOS values of SFs were measured with a novel colorimetric method. Independent t test and correlations were used to analyze the data.

RESULTS

TAC of SFs in patients with TMJ pain and limited mouth opening (LMO; n = 21) were significantly lower (P = 0.03) than patients without LMO (n = 21). TOS of SF was negatively correlated with duration of the disease. There was no correlation between TAC, TOS, and VAS scores of the patients as well as age and maximum mouth opening values.

CONCLUSIONS

Antioxidant response to oxidative changes (TAC and TOS) in SF decreased as the stage of dysfunction increased.

CLINICAL RELEVANCE

Local administration of antioxidant agents might be considered in management of TMJ pain and dysfunction to prevent possible increased oxidative stress.

Myositis ossificans traumatica of the temporalis muscle: a case report and diagnostic considerations

BACKGROUND

The present paper reported the case of a trauma-related myositis ossificans, with focus on considerations for a differential diagnosis process.

CASE REPORT

A 50-year-old male with a severe painful limitation (12 mm) of jaw opening referred a trauma to the right temporomandibular joint (TMJ) area occurring about 40 days before. Posttraumatic TMJ ankylosis was ruled out on the basis of negative magnetic resonance and cone-beam computerized tomography findings, and the patient underwent treatment with arthrocentesis, botulinum toxin injections, and physiotherapy on the basis of two diagnostic hypotheses, viz., an anchored disk phenomenon or a myofibrotic contracture of the right masseter muscle due to prolonged myospasm. After 4 months, jaw opening was slightly increased to 23 mm, but limitation and pain persisted. A new CT was performed to investigate for the emerging clinical picture compatible with traumatic myositis ossificans of the right temporalis muscle. Once the diagnosis was confirmed, the patient underwent surgery for coronoidectomy. At the 6-month follow-up, mouth opening was increased to up to 35 mm and pain was absent.

DISCUSSION

It is fundamental that patients suspected of having uncommon clinical pictures leading to mouth opening restriction are promptly referred to specialized centers, where the differential diagnosis process should be based on a comprehensive assessment taking into account for the potential etiologic factors described in the literature.

Inferior or double joint spaces injection versus superior joint space injection for temporomandibular disorders: a systematic review and meta-analysis

PURPOSE

To compare the effect and safety of inferior or double temporomandibular joint spaces drug injection versus superior temporomandibular joint space injection in the treatment of temporomandibular disorders.

MATERIALS AND METHODS

MEDLINE (via Ovid, 1948 to March 2011), CENTRAL (Issue 1, 2011), Embase (1984 to March 2011), CBM (1978 to March 2011), and World Health Organization International Clinical Trials Registry Platform were searched electronically; relevant journals as well as references of included studies were hand-searched for randomized controlled trials comparing effect or safety of inferior or double joint spaces drug injection technique with those of superior space injection technique. Risk of bias assessment with the tool recommended by Cochrane Collaboration, reporting quality assessment with CONSORT and data extraction, were carried out independently by 2 reviewers. Meta-analysis was delivered with RevMan 5.0.23.

RESULTS

Four trials with 349 participants were included. All the included studies had moderate risk of bias. Meta-analysis showed that inferior or double spaces injection technique could significantly increase 2.88 mm more maximal mouth opening (P = .0001) and alleviate pain intensity in the temporomandibular area on average by 9.01 mm visual analog scale scores (P = .0001) compared with superior space injection technique, but could not markedly change synthesized clinical index (P = .05) in the short term; nevertheless, they showed more beneficial maximal mouth opening (P = .002), pain relief (P < .0001), and synthesized clinical variable (P < .0001) in the long term than superior space injection. No serious adverse events were reported.

CONCLUSIONS

Inferior or double temporomandibular joint spaces drug injection technique shows better effect than superior space injection technique, and their safety is affirmative. However, more high-quality studies are still needed to test and verify the evidence.

A biomechanical basis for primary arthroplasty of the temporomandibular joint

Biomechanical principles of temporomandibular joint (TMJ) loading are unique, particularly in an orthopedic system that exhibits curvilinear general plane motion. Certain type-specific derangements can be surgically challenging and may primarily require open arthrotomy techniques rather than arthroscopy. This article discusses the basic biomechanical principles in normal and pathologic function. Three-dimensional preoperative imaging of TMJs is necessary for appropriate assessment of all patients and when open techniques are necessary as the initial surgical procedure.

Anchored disc phenomenon with a normally positioned disc in the temporomandibular joint: Characteristics and behaviour

We aimed to elucidate the pathogenesis and evaluate the therapeutic behaviour of patients with an anchored disc phenomenon but a normally positioned disc of the temporomandibular joint (TMJ). Fourteen patients with internal derangement including closed lock of one TMJ were examined. All had normally positioned discs. Synovial fluid was collected from the TMJ by arthrocentesis. Their symptoms, and the protein concentration in the synovial fluid, were evaluated. Their median duration of illness was 3 months (range 0.5-12), and the median protein concentration was low (343 microg/ml; range 36-791). Arthrocentesis was successful in nine. Arthroscopic findings in the five unsuccessful cases showed severe intra-articular adhesions of the TMJ. The main intra-articular pathological feature was the presence of adhesions, which might be affected by low protein concentrations in the synovial fluid. These findings may provide a new treatment in patients with normally positioned discs, despite the small number studied.

Anterior displacement of the TMJ disk: repositioning of the disk using a Mitek system. A 3D finite element study

In this paper the behaviors of the temporomandibular joint (TMJ) with an anteriorly displaced disk without reduction and with a surgically repositioned one were compared with the response of a healthy disk during jaw opening. The movement of each joint was obtained imposing the same opening path between incisors and assuming that the movement of the condyle is determined by the passive action of the masticatory muscles and the restrictions imposed by the articulating surfaces and the ligaments. A fiber-reinforced porohyperelastic model was used to simulate the behavior of the articular disk. The influence of the friction coefficient in the diseased joint was also analyzed, finding that the final displacement of the complex condyle-disk was smaller as the friction coefficient increased. On the other hand, its displacement in the repositioned joint was different than in the healthy case because the artificial sutures used in the surgery do not fully stabilize the disk posteriorly as the retrodiscal tissue does. The stress response of the disk changed in both pathologic cases: in the displaced joint the highest stresses moved from the intermediate zone (healthy case) to the posterior band, and in the reconstructed one the most loaded zone moved posteriorly at total opening. Besides, local stress concentrations appeared in the neighborhood of the artificial sutures and therefore damage of the disk and releasing of the sutures might be possible postoperatively.

Disc and condyle translation in patients with temporomandibular disorder

OBJECTIVE

The purpose of this study was to elucidate causal relationship between disc and condyle range of movement and clinical signs and symptoms in patients with temporomandibular disorders (TMD), using magnetic resonance imaging (MRI).

STUDY DESIGN

The subjects comprised of a study group of 191 patients with TMD and a control group of 43 asymptomatic patients. The clinical assessment consisted of range of maximum mouth opening (MMO) and preauricular pain during mandibular function. After clinical and radiographic findings assessment, disc and condyle condition were examined by MRI and the range of movement was accordingly classified.

RESULTS

Disc displacement was observed in 156/191 (81.7%) of the study group and 9/43 (20.9%) of the control group. When disc and condyle mobility was presented around the eminence, wider MMO range was maintained, P < .05. Presence of osteoarthrosis (OA) was not correlated with preauricular pain, because OA variables were mild in the study group.

CONCLUSION

Maintenance of disc/condyle translation is an important factor in TMJ function, irrespective of disc displacement or arthritis.

The role of surgery in the management of disorders of the Temporomandibular Joint: a critical review of the literature. Part 1

Despite the controversy surrounding the role of surgery in the management of Temporomandibular Disorders (TMD), studies in peer review journals continue to support the role of surgery as a legitimate means of treating pain and dysfunction in the Temporomandibular Joint (TMJ). To better understand the role of surgery in the management of TMJ disorders, a critical review of the literature will be presented in two parts. Part 1 reviews the evolution of TMJ surgery together with the biological evidence for surgical disease. History teaches us that we are destined to repeat the mistakes of the past if we fail to properly reflect on what has already been achieved and where the failures have occurred. With the help of molecular biology, the future of TMD management may comprise more carefully targeted and less radical treatment modalities.

Motivation, characterization, and strategy for tissue engineering the temporomandibular joint disc

The purpose of this review is to serve as the standard point of reference in guiding researchers investigating the tissue engineering of the temporomandibular joint (TMJ) disc. Tissue engineering of the TMJ disc is in its infancy, and currently there exists a gap between the tissue engineering community and the TMJ characterization community. The primary goal is to help bridge that gap by consolidating the characterization studies here as a reference to researchers attempting to tissue engineer the TMJ disc. A brief review of TMJ anatomy is provided, along with a description of relevant pathology, current treatment, and a rationale for engineering the TMJ disc. The biochemical composition and organization of the disc are reviewed, including glycosaminoglycan (GAG) and collagen content. The collagen of the disc is almost exclusively type I and primarily runs anteroposteriorly through the center and in a ringlike fashion around the periphery. The GAG content is approximately an order of magnitude less than that of hyaline cartilage, and although the distribution is not entirely clear, it seems as though chondroitin and dermatan sulfate are by far the primary GAGs. Cellular characterization and mechanical properties under compression, tension, and shear are reviewed as well. The cells of the disc are not chondrocytes, but rather resemble fibrocytes and fibrochondrocytes and may be of the same lineage. Mechanically, the disc is certainly anisotropic and nonhomogeneous. Finally, a review of efforts in tissue engineering and cell culture studies of the disc is provided and we close with a description of the direction we envision/propose for successful tissue engineering of the TMJ disc.

Closed lock (MRI fixed disc): a comparison of arthrocentesis and arthroscopy

Twenty-six patients with a sudden-onset of persistent limited mouth opening and with MRI signs of articular discs fixed to the glenoid fossa were studied. After unsuccessful non-surgical treatment, arthroscopy with sodium hyaluronate infusion was performed in 16 joints. Follow-up ranged from 24 to 60 months (mean: 30.3 months). All patients were clinically assessed preoperatively, and at 1, 3, 6, 9, 12, 18 and 24 months postoperatively. The clinical variables analysed were: joint pain using a visual analogue scale (VAS) (1-15), joint noises (clicking, crepitus or none), history of locking, duration of the symptoms, maximal interincisal opening (MIO), maximal protrusive movement (MP) and maximal contra-lateral movement (ML). MRI images were obtained preoperatively to analyse the morphological and dynamic characteristics of the temporomandibular joint. Eight of the patients who refused to undergo arthroscopy were treated with arthrocentesis. These patients were studied following the same criteria as stated above. Mean age of the group was 24.3 years (16-35 years). 20 patients were female and 6 male. The preop-MRI examination revealed a normal disc position in 16 joints and an anteriorly displaced disc in 10 cases. All of the discs were fixed to the glenoid fossa preventing an anterior translation of the condylar head. After non-surgical treatment only two patients improved while all the other patients showed a severe decrease in the MIO (mean 23.3 +/- 2.2 mm), LM (3.8 +/- 1.4) and a high pain level (9.7 scale). Sixteen patients underwent arthroscopy. A significant reduction in pain was noted after arthroscopy. Furthermore, a significant increase in MMO and LM was demonstrated postoperatively. Arthroscopic findings included the presence of adherences and synovitis. Eight patients who refused arthroscopy were treated with TMJ arthrocentesis. All such patients improved their symptoms postoperatively. In conclusion both TMJ arthroscopy and arthrocentesis give good results upon treating patients with anchored disc phenomenon (ADP).

'Friction and adhesive forces'--possible underlying causes for temporomandibular joint internal derangement

Since normal temporomandibular joint (TMJ) movements depend primarily on the disc freely sliding down the slope of the eminence, understanding how aberrations in the lubrication system contribute to TMJ dysfunction is clearly critically important. It provides a possible explanation for the genesis of disc displacement and helps make us familiar with the clinical appearance and ways of treating limited mouth opening caused by the anchored disc phenomenon (ADP) versus disc displacement without reduction, TMJ open lock versus dislocation and osteoarthritis. This understanding clarifies the efficiency of procedures such as joint hydraulic pump, arthrocentesis and arthroscopic lavage and lysis particularly in ADP, open lock and osteoarthritis.

Changes in the reducing power of synovial fluid from temporomandibular joints with "anchored disc phenomenon"

PURPOSE

In this study, we examined the hypothesis that uncontrolled oxidative stress causes collapse of the lubrication system, which is considered a major initiator of temporomandibular joint (TMJ) dysfunction. The oxidative stress was evaluated by measuring the overall antioxidant capacity of the low-molecular-weight antioxidants in the TMJ, using cyclic voltammetry (CV), in synovial fluid from normal and anchored disc phenomenon (ADP) TMJs.

MATERIALS AND METHODS

Synovial fluids samples were taken from 13 normally functioning and 33 ADP TMJs. The samples were frozen initially on collection and analyzed in CV to measure their overall reducing power.

RESULTS

CV measurements of the fluids collected from 90% of the healthy joints showed an anodic waves at peak potential [Ep(a)1/2] of 290 +/- 30 mV. Of the samples 56% showed another wave at 650 +/- 100 mV. These waves were generally absent in the fluid collected from ADP TMJs, but 2 new waves at 465 +/- 90 mV and greater than 750 mV were detected in 68% and 87% of the patients, respectively.

CONCLUSIONS

The results show more anodic waves, most of which of higher potentials (greater than 750 mV) in ADP TMJs, indicating that the capacity to cope with oxidative stress is lower in these joints. It is not clear whether this is due to absence of low-molecular-weight antioxidants or their consumption by uncontrolled production of reactive oxygen species, which might be the initial step in the collapse of the lubrication system.

A review of 56 cases of chronic closed lock treated with temporomandibular joint arthroscopy

PURPOSE

The aims of this prospective clinical study were to look at the features that constitute chronic closed lock of the temporomandibular joint (TMJ) and to assess the effectiveness of TMJ arthroscopic lavage and lysis in the management of this condition.

PATIENTS AND MATERIALS

Sixty joints in 56 patients who presented with mandibular hypomobility suggestive of chronic closed lock were prospectively examined and treated with TMJ arthroscopic lavage and lysis during a 3-year period from 1996 to 1999.

RESULTS

Eighty-seven percent (49 of 56) of patients were found to have chronic closed lock of the TMJ. The most common intra-articular findings were fibrillation (76%) and synovitis (54%). TMJ arthroscopic lavage and lysis were found to be effective in the management of chronic closed lock in 84% (47 of 56) of patients, with an average 66% reduction in pain levels and a mean improvement of 9.8 mm in interincisal mouth opening up to 6 weeks after the procedure.

CONCLUSIONS

Chronic mandibular hypomobility is a clinical sign that is often but not always caused by chronic closed lock of the TMJ. The intra-articular findings of this study suggest that cartilage degradation and synovial inflammation are important components of chronic closed lock of the TMJ that respond well to arthroscopic lavage. Patients with mandibular hypomobility not caused by closed lock of the TMJ (ie, myofascial pain and dysfunction, osteoarthrosis, and others) are less likely to derive benefit from arthroscopic lavage and lysis, so other treatment methods should be considered.

Adhesive force: the underlying cause of the disc anchorage to the fossa and/or eminence in the temporomandibular joint--a new concept

The commonly held cause for using the closed lock technique is the prevention of disc sliding by using the non-reducible disc. The purpose of this study was to re-evaluate the pathogenesis of sudden and persistent severely limited mouth opening associated with a total lack of disc sliding in view of the fact that it is promptly released by lavage of the upper compartment of the temporomandibular joint (TMJ). The proposed pathogenesis is based upon earlier clinical and laboratory findings of the first author coupled with pertinent information culled from the literature. It is suggested that sliding of the disc in the TMJ is enabled due to the presence of phospholipids protected by hyaluronic acid (HA) that constitute an efficient lubrication system. Joint overloading may be associated with uncontrolled production of reactive oxygen species (ROS) that causes degradation of the HA, followed by the exposure of the phospholipids to lysis by phospholipase A2 (PLA2). The denuded, smooth and elastic articular surfaces that possess high surface energy become strongly adherent when placed in direct physical contact with each other. The presence of an extremely thin film of fluid (sub-boundary lubrication) between the mating surfaces may cause even higher adhesion. These adhesive forces are probably responsible for the flexible disc anchorage to the fossa and/or eminence. They also explain the immediate release of the disc and rehabilitation of its sliding following arthrocentesis. Since it is uncommon for two opposing surfaces to be stripped bare and to become adherent, the likelihood of anchored disc phenomenon (ADP) occurring and recurring is very low.

Effect of arthrocentesis on TMJ disturbance of mouth closure with loud clicking: a preliminary study

The objective of this study was to evaluate the short-term effect of arthrocentesis on temporomandibular joint disturbance of mouth closure with loud clicking compared to the effect of one-time pumping into the joint space previous to arthrography. Twenty-one consecutive patients (22 joints) with loud clicking during mouth closure were enrolled. All were unable to smoothly close the mouth without effort. Eleven patients (12 joints) were examined using magnetic resonance imaging (MRI) to determine disk position. They then underwent arthrocentesis. Ten patients (10 joints) underwent arthrography alone as controls. Six months later, changes in clicking and temporomandibular joint movement were analyzed and the disk position was re-examined. There was improvement of mouth closing and clicking occurred in nine joints from the arthrocentesis group and two joints from the control group, with a significant difference between the two groups. Arthrocentesis may be indicated for patients with temporomandibular joint dysfunction and loud clicking when mouth closing.

Electron microscope and biochemical observations of the surface active phospholipids on the articular surfaces and in the synovial fluid of the temporomandibular joint: a preliminary investigation

PURPOSE

The goal of this article is to investigate the surface-active phospholipids located on the articular surfaces and in the temporomandibular joint (TMJ) synovial fluid (SF) by means of electron microscopy and biochemical analysis.

MATERIALS AND METHODS

Synovial fluids and articular cartilage samples taken from 6 normally functioning TMJs were studied. The osmiophilic lining of human TMJ articular surfaces has been studied by using special nondestructive fixation procedures. To study the SF, negative staining technique has been used. In addition, thin-layer chromatography has been used to identify the phospholipids extracted from synovial fluid of human TMJs.

RESULTS

In the SF, granular bodies were identified with diameter of between 170 and 280 nm. Their diameter decreased dramatically when exposed to phospholipase-A(2). The amorphous and highly osmophilic material on the articular surface include membrane-bound vesicles (270 nm in diameter) with lamellated pattern surrounding the amorphous-dense core. Biochemical extraction revealed phosphatidylcholine as the major component of the polar lipids.

CONCLUSIONS

This preliminary study presents findings that suggest that phospholipids present in the TMJ may provide an efficient boundary lubrication that enables the disc to slide down the slope of the eminence on joint function.

The use of arthrocentesis for the treatment of osteoarthritic temporomandibular joints

PURPOSE

The purpose of this retrospective study was to determine the efficacy of arthrocentesis in restoring the functional capacity of osteoarthritic temporomandibular joints (TMJ).

PATIENTS AND METHODS

This study involved 36 patients (29 females, 7 males; age range, 16 to 54 years, mean, 37.36 +/- 14.60 years) presenting with 38 dysfunctional joints that had not responded to conservative treatment. The postarthrocentesis status (follow-up period 6 to 62 months, mean 20.7 +/- 20.5 months) of the TMJs was determined by patient self-evaluation using visual analog scales and clinical examination.

RESULTS

Of the 38 TMJs treated with arthrocentesis, 26 joints reacted favorably to the treatment; pain and dysfunction scores were reduced from 9.86 +/- 0.73 to 3.39 +/- 0.76 and from 11.34 +/- 0.66 to 3.4 +/- 0.69, respectively (P <.001). Self-assessed general improvement/deterioration was +4.90 +/- 2.10 (on a scale of -7 to +7). Maximal mouth opening increased from 24.40 +/- 2.70 mm to 43.20 +/- 3.10 mm (P <.001). Lateral and protrusive jaw movements also increased in magnitude. In 14 patients in whom no improvement was noted, arthrocentesis acted as a diagnostic tool before surgical treatment.

CONCLUSIONS

Arthrocentesis is a safe and rapid procedure that in many instances results in the osteoarthritic TMJs returning to a healthy functional state. Failure of arthrocentesis suggests that the painful limitation is most probably caused by changes such as fibrous adhesions or osteophytes that require surgical intervention for their removal.

The role of hyaluronic acid in protecting surface-active phospholipids from lysis by exogenous phospholipase A(2)

BACKGROUND

This in vitro study aimed to elucidate the extent and kind of involvement of hyaluronic acid (HA) in the currently accepted view of synovial joint lubrication, in which surface-active phospholipids (SAPL) constitute the main boundary lubricant. The integrity of SAPL is apparently threatened by the lysing activity of phospholipase A(2) (PLA(2)).

METHODS

The effects of increasing concentrations of HA degraded by free radicals and non-degraded HA on the lysing activity of PLA(2) were examined in vitro. Liposomes (lipid model membrane) containing phosphatidylcholine (PC) were used as the substrate, on the assumption that they are appropriate representatives of SAPL.

RESULTS

HA adhered to the phospholipid membrane (liposomes), inhibiting their lysis by PLA(2). However, in its degraded form, HA not only failed to inhibit PLA(2)-lysing activity, but accelerated it.

CONCLUSIONS

It is reasonable to assume that HA plays an important indirect role in the steady state of the boundary lubrication process of joints by protecting SAPL from being lysed by PLA(2). However, as excessive loading generates free radicals within the joint (among other effects), the HA that is degraded in this way is incapable of protecting SAPL from lysis by PLA(2). When the rate of degradation exceeds that of synthesis, there will be insufficient replacement of HA and/or SAPL, resulting in denudation of the articular surfaces. These are then exposed to increasing friction, and hence increased danger of degenerative joint changes.

Validity of clinical diagnostic criteria for temporomandibular disorders: clinical versus magnetic resonance imaging diagnosis of temporomandibular joint internal derangement and osteoarthrosis

OBJECTIVES

Research is needed to assess the validity of clinical decision criteria for the diagnoses of temporomandibular disorders. The objective of this study was to assess the reliability of clinical diagnoses in predicting magnetic resonance imaging diagnoses of temporomandibular joint internal derangement and osteoarthrosis in a patient pain group with temporomandibular disorders.

METHODS

One clinician used the Clinical Diagnostic Criteria for Temporomandibular Disorders to classify 163 consecutive patients with temporomandibular disorders on physical diagnosis. The radiologist subsequently performed magnetic resonance imaging on 326 temporomandibular joints. Diagnostic agreement was determined for the diagnostic categories of absence of internal derangement, disk displacement with reduction, disk displacement without reduction, and osteoarthrosis.

RESULTS

Use of the Kappa statistic test indicated a poor diagnostic agreement between the clinician and the radiologist.

CONCLUSIONS

The classification system of the Clinical Diagnostic Criteria for Temporomandibular Disorders provides insufficient reliability for determination of the presence of temporomandibular joint internal derangement and osteoarthrosis. It should be supplemented by evidence from cross-sectional and longitudinal investigations to assess decisive differences in the areas of pathogenesis, treatment, and prognosis.

The process of lubrication impairment and its involvement in temporomandibular joint disc displacement: a theoretical concept

PURPOSE

This article re-evaluates the chain of events leading to temporomandibular joint (TMJ) disc displacement. The joint lubrication system and the process of its breakdown are clarified and an attempt is made to evaluate the possible effect of increased friction between the disc and fossa on the anterior displacement of the disc.

MATERIALS AND METHODS

The study is based on the author's accumulated clinical data and results obtained from laboratory investigations regarding TMJ lubrication and its possible breakdown, coupled with pertinent information culled from the literature.

RESULTS

Translation of the disc in the TMJ is enabled due to the presence of phospholipids and hyaluronic acid, which constitute an efficient lubrication system. This system may break down in the presence of uncontrolled free radicals. In the absence of lubricants, the articular surfaces are smooth, elastic in texture, and possess strong surface energy. Such opposing planes, especially in the presence of a thin fluid film (sub-boundary lubrication) tend to generate high friction while the disc is sliding against the fossa. Such friction is probably the prime mover in loosening the disc attachments to the condyle, with subsequent disc displacement.

CONCLUSIONS

Increased friction of the contiguous parts may well be a major causative factor in displacement of the articular disc. This should be taken into account in considering the appropriate treatment approach. It also raises some doubts regarding the validity of using repositioning techniques.

Comparison of the effectiveness of arthrocentesis in acute and chronic closed lock: analysis of clinical and arthroscopic findings

The objective of this study was to investigate the effectiveness of temporomandibular joint arthrocentesis in acute and chronic closed lock patients. Eighteen patients with closed lock of the temporomandibular joint (TMJ) were treated with fine needle fiber arthroscopic observation following arthrocentesis. Maximal mouth opening (MMO) and intensity of pain (VAS) were evaluated at pretreatment and each posttreatment appointment (one week, one month, three months following treatment). The clinical and arthroscopic findings were analyzed categorizing two groups into: good (A) and poor (B) groups. At pretreatment there was no significance relative to age or the mean MMO and VAS between the groups, but the mean of duration of the symptoms in group B was significantly longer than in group A (P < 0.03). Group B showed more severe synovitis, adhesions, and chondromalacia than group A (P < 0.01). Results suggest that arthrocentesis is more effective in closed lock of short duration where there is less severe synovitis, adhesions, and chondromalacia.

Extraoral facial pain

Craniofacial pain is a common chief complaint and is among the most frustrating diagnostic and treatment challenges encountered by emergency physicians. The efficient development of a differential diagnosis, the delivery of appropriate and effective therapies, and the appropriate referral of patients who present with craniofacial pain from extraoral sources are discussed. Disease descriptions, a diagnostic workup format, and acute management protocols are presented for the more common craniofacial pain entities.

Long-term evaluation of arthrocentesis for the treatment of internal derangements of the temporomandibular joint

PURPOSE

Arthrocentesis is being used for treatment of patients with temporomandibular joint disorders, including anterior disc displacement with and without reduction. This study was designed to examine the long-term effects of temporomandibular joint arthrocentesis in such patients and to evaluate their overall satisfaction with this treatment.

PATIENTS AND METHODS

The study was based on the review of patients' records, a written questionnaire (self-evaluation), and clinical examination. Visual analog scales (VAS) were used for evaluation of pain and dysfunction. Twenty-six patients (39 joints) who had been treated at the Medical College of Virginia Hospital, Virginia Commonwealth University, were included in the study. There were 32 joints with anterior disc displacement without reduction (ADsR) and 7 joints with anterior displacement with reduction (ADcR). Patients all had undergone arthrocentesis as outpatients. Follow-up evaluations ranged from 10 to 96 months, with a mean of 48.7 months.

RESULTS

Maximum vertical opening (MVO) prearthrocentesis ranged from 20 to 40 mm, with a mean of 25.3 +/- 5.5 mm. Immediately after arthrocentesis, the MVO ranged from 30 to 55 mm, with a mean of 43.8 +/- 5.6 mm. Maximum vertical opening at long-term follow-up ranged from 15 to 50 mm, with a mean of 37.1 +/- 8.8 mm. There was a significant increase in MVO between prearthrocentesis and postarthrocentesis both short- and long-term (P < .001). The short- and long-term postoperative VAS values for pain and dysfunction showed a significant decrease (P < .001) when compared with the VAS values preoperatively. Fourteen of the 26 patients (54%) no longer experienced pain, and the remaining 9 had less pain than before arthrocentesis as assessed by self-evaluation and clinical examination. Three of 26 patients had improvement for a period, later relapsed, and required subsequent surgery. Twenty-three of the 26 patients (88%) were completely satisfied with their treatment. Overall, an 88% success rate was achieved.

CONCLUSION

Arthrocentesis can reduce pain and dysfunction, both short- and long-term, in patients with anterior disc displacement.