Boudewijn Stegenga

TISSUE RESPONSES TO DEGENERATIVE CHANGES IN THE TEMPOROMANDIBULAR-JOINT - A REVIEW

The articular cartilage covering of the mandibular condyle and the articular eminence, as well as the tissue of the articular disc, may be affected by degenerative changes associated with osteoarthrosis. Degenerative changes of cartilage alter its physical properties and, as a result, affect its ability to withstand compressive and shearing stresses. Increased friction between the articular surfaces may impair joint movement and may elicit compensatory or pathologic responses of the cartilage and the adjacent tissues, such as capsule and ligaments, synovial membrane, subchondral bone, and associated musculature. In this review, these structural changes are described and related to common signs and symptoms of craniomandibular dysfunction, such as clicking, locking and instability, pain and tenderness, restricted ranges of mandibular motion, crepitation, deformity, muscle wasting, and changes of occlusion.

OSTEOARTHROSIS AS THE CAUSE OF CRANIOMANDIBULAR PAIN AND DYSFUNCTION - A UNIFYING CONCEPT

It has been demonstrated that osteoarthrotic changes in the temporomandibular joint (TMJ) and in other synovial joints show a similar course, both clinically and (ultra)microscopically. Initially, cartilage changes and possibly also changes in the synovial membrane set up a vicious cycle of cartilage breakdown accompanied by attempts at repair. When the degradative process exceeds the response of repair, the osteoarthrotic disorder progresses into clinically detectable stages. Frequently, the gliding capacity of the articular disc is also impaired, giving rise to an internal derangement. In this article, a concept is presented in which it is suggested that in many cases of craniomandibular pain and dysfunction TMJ osteoarthrosis is the basic disorder.

Efficacy and co-morbidity of oral appliances in the treatment of obstructive sleep apnea-hypopnea: A systematic review

The Obstructive Sleep Apnea-Hypopnea Syndrome (OSAHS) is a common sleep-related breathing disorder characterized by repetitive obstructions of the upper airway during sleep. Modification of pharyngeal patency by Oral Appliance (OA) therapy has been suggested as an alternative to various treatment modalities for OSAHS. To determine the evidence base with respect to the efficacy and co-morbidity of OA therapy in OSAHS, we conducted a systematic review of the available literature. Primary outcome measures were the reduction in number of upper-airway obstructions and co-morbidity related to the craniomandibular or craniofacial complex, respectively. Eligible studies regarding efficacy were independently assessed by two assessors using a quality assessment scale. Effect sizes of methodologically sound studies were calculated. In identical interventions, effect sizes were pooled with the use of a random-effects model. Given the scarcity of controlled studies related to co-morbidity, appraisal was confined to a description of eligible studies. Sixteen controlled trials related to efficacy were identified. With respect to the primary outcome measure, OA therapy was clearly more effective than control therapy (pooled effect size, -0.96; 95% confidence interval [CI], -1.49 to -0.42) and possibly more effective than uvulopalatopharyngoplasty. Although patients generally preferred OA therapy, improvement of respiratory variables, such as the number of upper-airway obstructions, was usually better in Continuous Positive Airway Pressure (CPAP) therapy (pooled effect size, 0.83; 95% CI, 0.59 to 1.06). Moreover, specific aspects related to OA design may influence patient-perceived efficacy and preference. Twelve patient-series and one controlled trial related to co-morbidity were identified. Analysis of the data suggests that OA therapy may have adverse effects on the craniomandibular and craniofacial complex. Although CPAP is apparently more effective and adverse effects of OA treatment have been described, it can be concluded that OA therapy is a viable treatment for, especially, mild to moderate OSAHS. Controlled studies addressing the specific indication and co-morbidity of OA therapy are warranted.

Pathology of temporomandibular joint internal derangement and osteoarthrosis

Temporomandibular joint (TMJ) osteoarthrosis and disk displacement seem to be strongly related, but they may also represent mutually independent temporomandibular disorders. This paper presents relevant aspects of normal physiology and degeneration of synovial joints, aspects of normal temporomandibular articular disk physiology and of displacement of the disk, the relationship between TMJ osteoarthrosis and disk displacement, and a general classification of temporomandibular disorders.

Long-term results of nonsurgical management of condylar fractures in children

Twenty-five patients with 28 condylar or subcondylar fractures, sustained during their growth period and treated nonsurgically, have been followed for an average period of 15 years. The fractures were classified as intracapsular, high condylar neck and low condylar neck fractures. In 5 patients, two weeks of intermaxillary fixation, followed by elastic traction in order to achieve a proper occlusion, was applied. All the other patients were treated by instruction, exercises and observation. In 4 patients, subsequent orthodontic treatment was provided. It is not advocated to perform orthodontic aftercare as a routine action in all patients. Satisfaction with the treatment results, as measured on a visual analogue scale (VAS), was very high. The masticatory function of all patients at last follow-up was good to excellent. From this study, it appears that especially the commonly occurring high condylar fractures (64%) show good regeneration tendency as observed on radiographs. Low condylar and intracapsular fractures may give rise to some asymmetry. In 4 cases this asymmetry was clearly visible to the experienced observer, but did not concern the patient. One patient (low condylar neck fracture) showed obvious malocclusion and facial asymmetry, which needed to be corrected by orthognathic surgery. Unfortunately, it is impossible to predict which type of fracture is at risk of facial asymmetry. It is concluded that nonsurgical management of condylar fractures of the mandible in children is still the method of choice.

Radiographic signs of temporomandibular joint osteoarthrosis and internal derangement 30 years after nonsurgical treatment

The aim of this study was to evaluate with radiographs the long-term status of temporomandibular joints that were treated nonsurgically for reducing disk displacement (group 1) or permanent disk displacement (group 2) 30 years ago. Transcranial and transpharyngeal radiographs were made before (T1), 2 to 4 years after (T2), and 30 years after (T3) nonsurgical treatment in 65 former patients with temporomandibular joint osteoarthrosis. To control the results for aging 35 matched subjects (group 3) underwent the same radiographic examination. The number and severity of radiographically visible degenerative changes increased significantly from T1 through T2 to T3 in group 1 and in group 2. The increase in these changes was not simply caused by aging, because in approximately three quarters of the temporomandibular joints in group 3, no radiographically visible degenerative changes were found. At all occasions group 2 showed significantly more severe changes than group 1. At T3 in 64% of the temporomandibular joints in group 1, no or only slight radiographically visible degenerative changes were observed, whereas in 86% of the temporomandibular joints in group 2, moderate to severe changes were observed. A persisting reducing disk displacement in part of the temporomandibular joints in group 1 might explain this significant difference. In 79% of the temporomandibular joints with moderate to severe radiographically visible degenerative changes at T1, no or only slight progression in the extent of these changes was seen between T2 and T3. Apparently a radiographically stable end stage may be reached within a few years after permanent displacement in most cases. It was concluded that in temporomandibular joints with reducing disk displacement, no or only slight radiographically visible degenerative changes develop, even if this condition persists for several decades. On the other hand, in temporomandibular joints with permanent disk displacement, radiographically visible degenerative changes are extensive in the vast majority of cases.

Epidemiology and natural progression of articular temporomandibular disorders

The reported prevalence of temporomandibular disorders (TMDs) differs from study to study, probably because of methodologic errors and lack of standardized definitions of TMDs and their characteristics. Classification of TMDs should be in accordance with classification of synovial joint disorders as generally used by rheumatologists and orthopedic surgeons, in which articular disorders are distinguished from nonarticular disorders. Articular temporomandibular disorders appear to be self-limiting in a very high percentage of cases. Because of this nonprogressive nature, the outcome of nonsurgical management will be highly successful.

Obstructive Sleep apnea Therapy

In clinical practice, oral appliances are used primarily for obstructive sleep apnea patients who do not respond to continuous positive airway pressure (CPAP) therapy. We hypothesized that an oral appliance is not inferior to CPAP in treating obstructive sleep apnea effectively. We randomly assigned 103 individuals to oral-appliance or CPAP therapy. Polysomnography after 8–12 weeks indicated that treatment was effective for 39 of 51 persons using the oral appliance (76.5%) and for 43 of 52 persons using CPAP (82.7%). For the difference in effectiveness, a 95% two-sided confidence interval was calculated. Non-inferiority of oral-appliance therapy was considered to be established when the lower boundary of this interval exceeded −25%. The lower boundary of the confidence interval was −21.7%, indicating that oral-appliance therapy was not inferior to CPAP for effective treatment of obstructive sleep apnea. However, subgroup analysis revealed that oral-appliance therapy was less effective in individuals with severe disease (apnea-hypopnea index > 30). Since these people could be at particular cardiovascular risk, primary oral-appliance therapy appears to be supported only for those with non-severe apnea.

Hard and soft tissue imaging of the temporomandibular joint 30 years after diagnosis of osteoarthrosis and internal derangement

PURPOSE This article describes the clinical and imaging findings in the temporomandibular joints (TMJs) of patients 30 years after the initial diagnosis of osteoarthrosis and internal derangement. PATIENTS AND METHODS Fifty-five TMJs with a history of osteoarthrosis and internal derangement and 37 contralateral TMJs that were asymptomatic 30 years ago were examined in 46 former patients. To visualize degenerative changes of the bony parts of the TMJ, transpharyngeal and transcranial radiographs were made; to visualize disc position, sagittal T1-weighted magnetic resonance (MR) images were made. For comparison, 22 TMJs of an age-matched control group without complaints related to the masticatory system were similarly examined. RESULTS Thirty years after the initial diagnosis of osteoarthrosis and internal derangement, clinical signs in former patients hardly differed from those of control subjects. radiographic signs were significantly more common and more severe in former patients. A high percentage of osteoarthrosis and internal derangement was seen on MRI in both TMJs with a history of osteoarthrosis and internal derangement and in the contralateral TMJs. It appeared that osteoarthrosis and internal derangement in the contralateral TMJs had developed asymptomatically in most cases. None of the patients had required treatment for the contralateral TMJ; only one fourth of the patients had noticed symptoms. In the control subjects, osteoarthrosis and internal derangement were infrequently seen. A significant correlation was found between disc position and the severity of radiographically detectable degenerative changes of the TMJ. CONCLUSIONS It was concluded that 30 years after initial diagnosis there were few clinical signs of osteoarthrosis and internal derangement, although radiographic signs were extensive. Bilateral osteoarthrosis and internal derangement, with one symptomatic and one asymptomatic TMJ, is a common phenomenon. Moderate to severe radiographically detectable degenerative changes may be the only sign of an underlying internal derangement.

Smallest Detectable Difference in Outcome Variables Related to Painful Restriction of the Temporomandibular Joint

The smallest detectable difference is the smallest statistically significant change in measurement results. In the field of temporomandibular disorders, the smallest detectable difference is not a commonly used concept. Most outcome studies are based on comparisons of group means, although this does not provide information about individual changes or about the clinical relevance thereof. The smallest detectable difference for maximal mouth opening was calculated from previously published reliability coefficients and the standard deviations of different samples of healthy subjects and patients with complaints of the temporomandibular joint. The smallest detectable difference of pain intensity measured with different visual analogue scales was calculated from the reliability coefficients and standard deviations of a heterogeneous group of pain patients. The smallest detectable difference of function impairment was calculated for a group of patients with complaints of the temporomandibular joint. For maximal mouth opening in healthy subjects, the smallest detectable difference was 5 mm. Repeated measurements improved it to 3 mm. The smallest detectable difference on a visual analogue scale was 28 mm for actual pain intensity and 22 mm for minimal pain as well as for maximal pain intensity. For total function impairment of patients with complaints of the temporomandibular joint, the smallest detectable difference was 8 units on a 0 to 68 scale.