On the Perception of the Preferred Jaw Position in Patients with Symptoms of Temporomandibular Disorders

This paper considers the hypothesis that, in patients with temporomandibular disorders of myogeneous origin, oral muscle hyperactivity originates in deviant motor programs for oral behavior, based on erroneous proprioceptive information. Patients with various forms of TM dysfunction participated in the study; we measured each patient's ability to match jaw separations by referring to a self-generated internal standard, or preferred jaw position (PJP). The PJP establishment and its precision were considered an expression of a patient's propriocepsis. We measured PJP before, during, and after splint therapy in three groups of TMJ patients (a myogeneous, an arthogeneous, and a psychogeneous group) and looked at how values of PJP changed with therapy.

This longitudinal study shows that patients with TMJ disorders behave similarly to symptom-free dentate subjects when matching PJP. More than 80% of our patients are unstable in their jaw position preference, but the precision of determinating is constant. The values of instability and imprecision are of the same order (from 0.2–1.0 mm). We were unable to detect any correlation between matching behavior, the absolute values of PJP and its precision, our clinical TM dysfunction classification, changes in dysfunction index, and changes in clinical symptoms. We were also unable to detect any correlation between a trend in the values of PJP and the progress of therapy. Based on the results of this study, we conclude that propriocepsis of patients with TMJ disorders is not impaired, and our hypothesis is therefore falsified.     

Disk position and the bilaminar zone of the temporomandibular joint in asymptomatic young individuals by magnetic resonance imaging

OBJECTIVE: The purpose was to study the disk position of the temporomandibular joint (TMJ) in young individuals without any clinical signs or symptoms or history of internal derangement or degenerative joint disease and to study the features of the bilaminar zone of the TMJ in sagittal magnetic resonance (MR) images and the behavior of the bilaminar zone during jaw opening. STUDY DESIGN: MR imaging examinations of 80 TMJs of 40 symptom-free healthy subjects (20 women and 20 men) with a mean age of 26.9 years formed the basis of this study. RESULTS: In 33 of the 40 symptom-free subjects (82.5%), there was a normal relationship between disk and condyle at occlusion, whereas 5 individuals had unilateral disk displacement and 2 had bilateral disk displacement. The superior part of the bilaminar zone could be identified in all of the 40 symptom-free subjects. The inferior band of the bilaminar zone was identified bilaterally in 57.5% of individuals and unilaterally in 20%. In 9 subjects, the inferior band of the bilaminar zone could not be identified in any of the TMJs. CONCLUSIONS: Disk displacement of the TMJ occurred in approximately 20% of the young individuals in this sample. The use of both sagittal and oblique coronal MR images is of importance for classification of the position of the disk in that the oblique coronal imaging plane rendered significant complementary information to that of the sagittal images. The identification of both the superior and the posterior band of the bilaminar zone must be considered new information. The superior band remained consistently in contact with the fossa at the open-mouth position.     

Prevalence of clinical signs and pain symptoms of temporomandibular disorders and associated factors in adult Finns

Abstract

Objective: To assess the prevalence of clinical signs and pain symptoms of temporomandibular disorders (TMD) and associated factors in the Finnish adult population, as well as the association between self-reported TMD pain symptoms and clinical signs.

Material and methods: The sample consisted of 1577 Finnish adults who participated in the Health 2011 Survey (BRIF8901). Signs of TMD were assessed using clinical examination, and TMD pain symptoms were inquired using validated questions.

Results: Of the study subjects, 35% showed at least one sign of TMD, 8% reported weekly facial pain and 6% weekly pain when biting or jaw opening. According to logistic regression, female gender, poor general health and low level of education increased the risk for most TMD signs and TMD pain symptoms. Muscle or TMJ pain on palpation associated significantly with self-reported weekly facial pain or pain when biting or jaw opening.

Conclusion: Over a third of the population showed clinical signs of TMD and less than one-tenth reported TMD pain symptoms. An assessment of a patient’s general health needs to be a part of TMD diagnosis and treatment. The Finnish versions of the validated questions are applicable for screening of TMD pain.     

On the self-perception of jaw positions in man

A longitudinal study shows that, in the short-term, dentate subjects are able to match fairly well the magnitude of jaw separations to any of three types of memorized standards (imagined, verbally imposed and physically imposed) of various dimensions. All subjects showed instability of the comparison mechanism or long-term changes in the engram. About 66 per cent of the matches were performed with the same precision. The relative precision of the matches is almost independent of the size of the standard. The absolute precision of matching of dentate subjects is similar to that of edentulous subjects. In half of the experiments, the subjects showed a match that equals the magnitude of the verbal standard or the real standard. The subjects tend to give more accurate matches when they refer to a verbal standard than when they refer to a real standard, but the long-term instability of matching is much greater when the subjects refer to a verbal standard than when the subjects refer to a real standard.     

Factors influencing jaw position sense in man

The relative contribution of muscle sensors, joint sensors and trigeminal exterosensors to the position sense of the mandible was investigated. Subjects compared the sizes of gauges placed between the teeth with the size of a previously explored standard gauge of 4.75 mm. The experimental conditions were either anaesthesia of both mandibular joints and the oral exterosensors, or load on the jaw-closing muscles, or adaptation to an extreme jaw position. The results were compared with control experiments under normal conditions. (1) All subjects marched to standard fairly well in control conditions, the imprecision of the match being ~ 0.5 mm. Under anaesthesia, the matches were 1–1.5 mm greater than the controls, the imprecision being almost unaffected. Anaesthetizing the joints and oral exterosensors before or after exploring the standard gauge did not affect the match. Imposing various loads ($\text{}\text{?}$ 3.4kg) did not change the match to the standard. Adaptation to a wide open position introduced a considerable mismatch of the standard, leaving the imprecision of the match unaffected. (2) The experiments provide evidence that muscle afferents are important sources in sensing jaw position and fulfil the criteria for an independent position servo in the trigeminal system. It is suggested that the engram of the standard is built up mainly from muscle sensor information.     

Morphological and positional assessments of TMJ components and lateral pterygoid muscle in relation to symptoms and occlusion of patients with temporomandibular disorders

Disc displacement is accepted as one of major findings in temporomandibular disorders (TMD). However, the associations of disc positions with morphological and positional changes of temporomandibular joint (TMJ) components and lateral pterygoid (LP), TMD clinical symptoms, and occlusion have rarely been discussed quantitatively. In this study, the morphological and positional changes of TMJ components and LP were assessed by means of magnetic resonance imaging (MRI) and tomography of the TMJ in 41 TMD and nine control (CN) subjects. Disc positions in TMD subjects were divided into normal position (NP) and anterior displacement with and without reduction (ADR+ and ADR-, respectively). From MRI scans and tomograms, the morphological and positional changes of TMJ components and LP were measured and compared among CN, NP, ADR+ and ADR- groups. Correlations between these measurements and the scored clinical symptoms and occlusal factors were analysed in TMD subjects. The results indicated that: (1) TMJ osseous structures and LP showed no significant difference among CN and the three TMD groups, except for a posterior seat of condyle and shorter/steeper condylar movement during jaw opening; (2) disc length and inclination were significantly shorter and steeper, respectively, in ADR+ and ADR-; (3) disc positions were not specified by clinical symptoms and occlusal factors, except for the dominant TMJ sounds in ADR+; (4) an uncoordinated movement of the condyle/disc complex was found in ADR+ and/or ADR-; (5) TMJ osseous structures and the disc were weakly associated with clinical symptoms and occlusal factors. However, the LP showed negative associations with palpable pain for both the TMJ and jaw muscles and the static occlusal factors. These findings suggest that TMJ internal derangements are more related to the positional changes or spatial relationships of TMJ components but less to the individual morphologies of TMJ osseous structures, disc and LP, as well as specific clinical symptoms and occlusal factors, which might be in disagreement with a large body of previous statements.     

Relationship Between Habitual Occlusal Position and Flat Bite Plane Induced Occlusal Position in Volunteers With and Without Temporomandibular Joint Sounds

Abstract

The aim of this study was to assess whether temporomandibular joint (TMJ) sounds are associated with the difference between the habitual occlusal position (HOP) and the bite plane induced occlusal position (BPOP). Fifteen dental technician school students who had complete natural dentition, normal occlusion and who exhibited TMJ sounds were compared with fifteen healthy control subjects. HOP was recorded by voluntary jaw closing while in an upright position, and BPOP was recorded after wearing an anterior bite plane for a short period of time. Three interocclusal records were obtained in both positions with a vinyl polysiloxane material, and the recorded maxillomandibular relations were analyzed three-dimensionally and compared. Subjects with TMJ sounds had statistically larger differences between HOP and BPOP than controls (p<.05). Within this study population, an association was found between TMJ sounds and the difference between HOP and BPOP.     

Development of temporomandibular disorder symptoms: a 3-year cohort study of university students

The aims of this study were to examine the incidence of temporomandibular disorders (TMDs) over a 3-year period and to evaluate the risk of self-reported TMDs among university students in Japan. The study population comprised 2374 university students examined at the start of their undergraduate course and 492 students re-examined after 3 years using questionnaires on symptoms of TMD and experiences of jaw injury, stress, orthodontic treatment and parafunctional habits. Cumulative incidence (%) and relative risks were calculated overall. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to determine the degree of risks of these variables for symptoms of TMDs using logistic regression. Results of logistic regression analysis showed that male subjects with experience of jaw injury had a 3·54 (CI=1·45-8·68, P<0·01)-fold higher risk of temporomandibular joint (TMJ) pain than that for those who did not. Female subjects who reported experiencing stress and bruxism had 10·56 (CI=1·28-87·54, P<0·05)- and 5·00 (CI=1·21-20·71, P<0·05)-fold higher risks of TMJ sound, respectively, than the risk for female subjects who had not experienced stress or bruxism. The results indicated that experiences of jaw injury, stress and bruxism were significantly associated with increased risks of development of TMJ disorders in a 3-year cohort.     

Influence of oral stabilization appliances in intra-articular pressure of the temporomandibular joint

Aims:

This study analyzed the intra-articular pressure in the upper compartment of the temporomandibular joint (TMJ) under different functional conditions. The influence of stabilization appliances on intra-articular pressure was studied.

Methodology:

Seventy-four joints from 64 patients (55 women and 9 men; mean age: 43·2±11·86 years; range: 19–61 years) with TMJ disorders were examined. Only 50 joints passed the inclusion criteria. Intra-articular pressure was measured using a 21G needle inserted into the joint and connected to a pressure transducer. Pressure was measured with the jaw in the following positions: at rest, maximal mouth opening, clenching in maximal intercuspal position, and clenching with an oral interoclusal appliance.

Results:

Fifty joints were included in the study (without blood reflux), mean pressure at rest was negative (–6·06±4·55 mmHg); when the mouth was opened to its maximal position the pressure was lower (?26·09±6·42 mmHg). Mean intra-articular pressure was higher in the maximal intercuspal position (58·56±24·90 mmHg). When an interoclusal appliance device was fitted, mean intra-articular pressure reduced its value by 31·24%, which reached a mean value of 40·56±18·84 mmHg (P<0·001). There were no significant differences in sex. The group over 45 years old had higher pressure values in maximal open mouth position than the group of patients under 45 years old (P<0·02).

Conclusions:

Interoclusal appliances can reduce pressure in the upper compartment of the TMJ and improve functional status of the joint.     

TMJ symptoms and referred pain patterns

The purpose of this study was to determine the relationship between TMJ symptoms, (muscle tenderness, joint noise, deviant jaw opening and closing patterns, and limited jaw opening), and a history of referred pain patterns (earaches, headaches, neck pain, and sinus problems). A questionnaire was completed by 100 subjects regarding histories of the previously mentioned problems. The researcher then examined the subject's TMJs, and their symptoms were recorded as being present or absent. The following relationships were found to be significant: Headaches and lateral pterygoid muscle tenderness, Earache and medial pterygoid muscle tenderness, Neck pain and one or more tender muscles, Sinus problems and one or more tender muscles, Sinus problems and temporal muscle tenderness, Sinus problems and medial pterygoid muscle tenderness. However, r values for the above relationships were between 0.22 and 0.3 indicating that the relationships were not strong. It appears that some normal patients already have patterns of masticatory muscle tenderness and associated referred pain patterns prior to seeking treatment for acute TMJ symptoms.     

Clinical Indications for Simultaneous TMJ and Orthognathic Surgery

Abstract

There are many temporomandibular joint (TMJ) conditions that can cause pain, TMJ and jaw dysfunction, and disability. The most common of these conditions include: 1. articular disk dislocation; 2. reactive arthritis; 3. adolescent internal condylar resorption; 4. condylar hyperplasia; 5. osteochondroma or osteoma; and 6. end-stage TMJ pathology. These conditions are often associated with dentofacial deformities, malocclusion, TMJ pain, headaches, myofascial pain, TMJ and jaw functional impairment, ear symptoms, etc. Patients with these conditions may benefit from corrective surgical intervention. Open joint surgery provides direct access to the TMJ allowing manipulation, repair, removal and/or reconstruction of the anatomical structures that cannot be accomplished by other treatment methods. TMJ surgery and orthognathic surgery can be predictably performed during one operation with high success rates. This paper discusses the most common TMJ pathologies and presents the surgical management considerations to correct the specific TMJ conditions and associated jaw deformities.     

Craniomandibular function in juvenile chronic arthritis. A clinical and radiographic study

Craniomandibular function was studied in 70 subjects with juvenile chronic arthritis (JCA). The subjects represented the total group of children and adolescents with the diagnosis JCA in a Swedish county. At examination, the median age of the subjects was 11.9 years and the median duration of the disease was 2.6 years. The most important finding of the study was the high prevalence (41%) of radiographic signs of temporomandibular joint (TMJ) pathology. Few subjects showed the typical craniofacial abnormalities associated with JCA, like mandibular micrognathia, facial asymmetries and open bite. Subjective symptoms of dysfunction were almost absent in subjects younger than seven years but were reported by 56% of the older subjects. TMJ sounds and pain on jaw movements were the most frequent symptoms reported. At the clinical examination, TMJ crepitations and restricted horizontal jaw movements were noted in 26% and 32% respectively. The high prevalence of TMJ involvement found in this study underlines the importance that dentists become part of the medical team responsible for the treatment of children and adolescents with JCA.     

Orthodontic treatment and temporomandibular joint disorders.

The overall objective of this project was to study the relationship between orthodontic treatment and temporomandibular joint (TMJ) disorders. This relationship has been and remains an important and complex issue in orthodontics. The objectives of the study were to determine the incidence of TMJ pain and dysfunction in a group of orthodontic patients who were symptom-free on entering treatment, and to assess and characterize the level of pain and dysfunction in patients with symptoms, and track changes in these parameters during the course of orthodontic treatment. Standardized functional indices and physical measurements were used to describe and assess TMJ pain and dysfunction. The results of this study showed that of 451 patients without symptoms undergoing treatment at our university clinic during the 18-month project, no patient developed signs and symptoms of TMJ disorders during that time. In addition, for the 11 patients who presented with signs and symptoms of TMJ disorders at the time of their entry into the treatment program, no clear or consistent changes in levels of pain and dysfunction occurred longitudinally during the treatment period followed in this study. On the basis of these findings, a relationship between either the onset of TMJ pain and dysfunction and the course of orthodontic treatment or the change in TMJ pain and dysfunction and the course of orthodontic treatment could not be established in this particular patient population.     

The craniocervical connection: a retrospective analysis of 300 whiplash patients with cervical and temporomandibular disorders

Because the concept of whiplash as a causative factor for temporomandibular disorders (TMD) is highly controversial, we decided to do a retrospective analysis of patients treated in our office who had sustained whiplash injuries and were treated for cervical and temporomandibular disorders. The records of 300 patients with TMD preceded by a motor vehicle accident were examined retrospectively. The most common presenting symptoms, in order, were: jaw pain, neck pain, post-traumatic headache, jaw fatigue, and severe temporomandibular joint (TMJ) clicking. The most common TMD diagnoses were: masseter trigger points, closing jaw muscle hyperactivity, TMJ synovitis, opening jaw muscle hyperactivity, and advanced TMJ disk derangement. Based primarily on the physical examination, we concluded that the TMJ and surrounding musculature should be examined similarly to other joints, with no preconceived notion that TMD pathology after whiplash is unlikely.     

The silent period in the masseter muscle of patients with TMJ dysfunction.

The silent period (SP) following a jaw jerk elicited during sustained contraction in the masseter muscles has been studied in two groups of subjects, one with and one without, acute and distinct symptoms of TMJ dysfunction. The subjects with acute TMJ dysfunction symptoms showed significantly shorter latency and longer duration of the silent period and the period of their depressed activity (DA) was also significantly longer than in the group without TMJ dysfunction. The duration of the SP of both muscles was symmetrical in about 60% of subjects in each group. This study validates that the duration of the silent period may be a useful diagnostic tool of clinical interest.     

Centers of rotation during jaw movements

Anatomists consider the articulation of movable joints to be complex, involving movable instantaneous centers of rotation (ICR). However, prosthodontists often treat the temporomandibular joint (TMJ) as a model of a simple hinge. The aim of this study was to examine the case for a movable ICR during habitual opening and closing jaw movements. Young, dentate subjects were examined with a kinesiograph. Jaw movements were performed and recorded. The center of rotation of each movement pattern was identified, and its location related to the position of the TMJ. The results showed that opening and closing jaw movements were predominantly non-coincident, with a movable ICR located at a variable distance and direction from the TMJ. There was no evidence to suggest that the TMJ functioned as a simple hinge during jaw movements.     

Orofacial pain, jaw function, and temporomandibular disorders in women with a history of juvenile chronic arthritis or persistent juvenile chronic arthritis

OBJECTIVES: We sought to study the long-term outcome of juvenile chronic arthritis (JCA) in the temporomandibular joint (TMJ). STUDY DESIGN: Temporomandibular disorders, including TMJ involvement, were assessed in 42 women with pauciarticular or polyarticular JCA--on average 25.8 years from disease onset--and compared with those found in matched control subjects. Disease-related parameters associated with temporomandibular disorders were identified. RESULTS: The TMJ was involved in 66.7% of the patients, most severely in extended pauciarticular JCA. Temporomandibular disorders were more frequent in the patients than in the control subjects, especially in those with persistent disease. The TMJ involvement was positively correlated with disease duration and negatively correlated with jaw opening and occlusal support. Duration of active JCA and history of functional pain were identified as predictors of present TMJ involvement. CONCLUSION: In a long-term follow-up, TMJ involvement proved frequent in the studied patients and was associated with long disease duration and previous pain on jaw opening. The findings suggest that patients with JCA should undergo orofacial evaluation on a regular basis.     

Jaw closing movement and sex differences in temporomandibular joint energy densities

Energy densities (ED, mJ/mm³) quantify mechanical work imposed on articular cartilages during function. This cross‐sectional study examined differences in temporomandibular joint (TMJ) ED during asymmetric versus symmetric jaw closing in healthy females versus males. ED component variables were tested for differences between and within sexes for two types of jaw closing. Seventeen female and 17 male subjects gave informed consent to participate. Diagnostic criteria for temporomandibular disorders and images (magnetic resonance (MR), computed tomography) were used to confirm healthy TMJ status. Numerical modelling predicted TMJ loads (F_normal) consequent to unilateral canine biting. Dynamic stereometry combined MR imaging and jaw‐tracking data to measure ED component variables during 10 trials of each type of jaw closing in each subject's TMJs. These data were then used to calculate TMJ ED during jaw closing asymmetrically and symmetrically. Paired and Student's t tests assessed ED between jaw closing movements and sexes, respectively. Multivariate data analyses assessed ED component variable differences between jaw closing movements and sexes (α = 0.05). Contralateral TMJ ED were 3.6‐fold and significantly larger (P < .0001) during asymmetric versus symmetric jaw closing, due to significantly larger (P ≤ .001) distances of TMJ stress‐field translation in asymmetric versus symmetric movement. During asymmetric jaw closing, contralateral TMJ ED were twofold and significantly larger (P = .036) in females versus males, due to 1.5‐fold and significantly smaller (P ≤ .010) TMJ disc cartilage volumes under stress fields in females versus males. These results suggest that in healthy individuals, asymmetric compared to symmetric jaw closure in females compared to males has higher TMJ mechanical fatigue liabilities.     

Changes in signs and symptoms following temporomandibular joint disc repositioning surgery.

Fifty-one subjects with documented intra-articular pathology refractory to non-surgical therapy underwent temporomandibular joint (TMJ) disc repositioning surgery. Following surgery, subjects were evaluated for 6 months to 6 years by clinical examinations and questionnaires at designated times, and by postsurgical joint imaging. Significant decreases were noted in pain (headache, TMJ pain, ear pain, and neck/shoulder pain), the incidence of joint sounds and locking, and the presence of dietary restrictions. However, 35% of the subjects continued to have residual TMJ pain, and a similar percentage continued to need periodic nonsteroidal anti-inflammatory drugs for analgesia. Some degree of dietary restriction remained in approximately 50% of the subjects, and joint sounds persisted in a similar percentage following surgery. Mean mouth opening was improved by 8 mm, although lateral movements were increased by less than 0.5 mm. Surgery did not decrease the occurrence of jaw deviation, and disc position was unchanged in 86% of the joints imaged at an average of 2 years following surgery. Although TMJ disc repositioning surgery significantly improved pain and dysfunction in TMJ surgery patients, the improvement in disc position was not maintained in most subjects following surgery.     

Destructive psoriatic arthritis of the temporomandibular joint: a clinical case,an overview of the pathophysiology and its differential diagnoses

Abstract

Background Clinical assessments and uniplanar images in temporomandibular disorders are not always entirely reliable. This predicament is especially important when clinicians need to determine the nature of temporomandibular joint disease, particularly when clinical features are not helpful in determining the diagnosis.

Clinical presentation A 63-year-old female patient presented with mild pain in her right TMJ. During routine imaging exams, a destructive monoarticular arthritis was noticed, producing multiple erosions of the mandibular and temporal condyles. In addition, attrition of the ceiling of the glenoid fossa was observed, generating a communication with the endocranium. Only the presumptive biological behavior revealed on TMJ imaging and the appearance of the psoriatic plaques later during follow-up helped the authors to narrow the differential diagnosis.

Conclusion The clinical case presented illustrates the difficulties in diagnosing an erosive, seronegative TMJ destruction, suggestive of a systemic arthritis.