Michel H. Steenks

Osteochondroma of the mandibular condyle: A case report

Osteochondroma of the mandibular condyle is extremely rare and may cause signs and symptoms like those seen in patients with temporomandibular joint dysfunction. Differentiation between osteochondroma and condylar hyperplasia is not possible on histologic grounds alone, but the radiographic and intraoperative findings together are usually sufficient to establish a definite diagnosis.

Temporomandibular Joint Involvement is Associated with Quality of Life, Disability and High Disease Activity in Juvenile Idiopathic Arthritis

To evaluate the demographic, disease activity, disability, and health‐related quality of life (HRQOL) differences between children with juvenile idiopathic arthritis (JIA) and their healthy peers, and between children with JIA with and without clinical temporomandibular joint (TMJ) involvement and its determinants.

Fighting Against Disuse of the Masticatory System in Duchenne Muscular Dystrophy: A Pilot Study Using Chewing Gum

Duchenne muscular dystrophy patients report masticatory problems. The aim was to determine the efficacy of mastication training in Duchenne muscular dystrophy using chewing gum for 4 weeks. In all, 17 patients and 17 healthy age-matched males participated. The masticatory performance was assessed using a mixing ability test and measuring anterior bite force before, shortly after and 1 month after the training. In the patient group the masticatory performance improved and remained after 1-month follow-up, no significant changes in anterior maximum bite force was observed after mastication training. In the healthy subject the bite force increased and remained at the 1-month follow-up; no significant differences in masticatory performance were observed. Mastication training by using sugar-free chewing gum in Duchenne muscular dystrophy patients improved their masticatory performance. Since bite force did not improve, the working mechanism of the improvement in chewing may relate to changes of the neuromuscular function and coordination, resulting in improvement of skills in performing mastication.

Predictive factors for masticatory performance in Duchenne muscular dystrophy

Patients with Duchenne muscular dystrophy (DMD) report masticatory and swallowing problems. Such problems may cause complications such as choking, and feeling of food sticking in the throat. We investigated whether masticatory performance in DMD is objectively impaired, and explored predictive factors for compromised mastication. Twenty-three patients and 23 controls filled out two questionnaires about mandibular function, and underwent a clinical examination of the masticatory system and measurements of anterior bite force and masticatory performance. In the patients, moreover, quantitative ultrasound of the tongue and motor function measurement was performed. The patients were categorized into ambulatory stage (early or late), early non-ambulatory stage, or late non-ambulatory stage. Masticatory performance, anterior bite force and occlusal contacts were all reduced in the patient group compared to the controls (all p < 0.001). Mastication abnormalities were present early in the disease process prior to a reduction of motor function measurement. The early non-ambulatory and late non-ambulatory stage groups showed less masticatory performance compared to the ambulatory stage group (p < 0.028 and p < 0.010, respectively). Multiple linear regression analysis revealed that stage of the disease was the strongest independent risk factor for the masticatory performance (R(2) = 0.52). Anterior bite force, occlusal contacts and masticatory performance in DMD are severely reduced.

Bulbar muscle MRI changes in patients with SMA with reduced mouth opening and dysphagia

Objective: We performed a study in patients with proximal spinal muscular atrophy (SMA) to determine the prevalence of reduced maximal mouth opening (MMO) and its association with dysphagia as a reflection of bulbar dysfunction and visualized the underlying mechanisms using MRI. Methods: We performed a cross-sectional study of MMO in 145 patients with SMA types 1–4 and 119 healthy controls and used MRI in 12 patients to visualize mandibular condylar shape and sliding and the anatomy of muscle groups relevant for mouth opening and closing. We analyzed associations of reduced MMO with SMA severity and complaints of dysphagia. Results: Reduced MMO was defined as an interincisal distance ≤35 mm and was found in none of the healthy controls and in 100%, 79%, 50%, and 7% of patients with SMA types 1, 2, 3a, and 3b/4, respectively. MRI showed severe fatty degeneration of the lateral pterygoid muscles that mediate mouth opening by allowing mandibular condylar sliding but relatively mild involvement of the mouth closing muscles in patients with reduced MMO. Reduced MMO was associated with SMA type, age, muscle weakness, and dysphagia (p < 0.05). Conclusions: Reduced MMO is common in SMA types 1–3a and is mainly caused by fatty degeneration of specific mouth opening muscles. Reduced MMO is a sign of bulbar dysfunction in SMA.

Orthopedic diagnostic tests for temporomandibular and cervical spine disorders.

The interexaminer reliability of six orthopedic tests, applied to the masticatory system, was determined in a group of 79 patients with signs and/or symptoms of TMD. Multitest Scores were composed for each test and combinations of tests for the three main symptoms of TMD, namely, pain, joint sounds, and restriction of movement. Although the tests showed different reliability scores, the reliability of detecting these three main symptoms of TMD was satisfactory. All the tests contributed to the diagnostic process, with active movements being the most powerful test. The combination of active movements, passive movements, and palpation provided valuable diagnostic information. Other tests could be used for specific diagnostic problems. The scores of the orthopedic tests applied to the neck show that extension and flexion can be evaluated most reliably with active movements and by assessing end feel. The interexaminer agreement for recording pain was also satisfactory for flexion and extension. The interexaminer reliability of the tests recording pain and end feel in the shoulder girdle was moderate for anteflexion.

Mandibular dysfunction as a reflection of bulbar involvement in SMA type 2 and 3

Objective: In a cross-sectional study, we aimed to determine (1) the effect of spinal muscular atrophy (SMA) type 2 and 3 on mandibular function reflected as masticatory performance, mandibular range of motion, and bite force and (2) the predictors of mandibular dysfunction. Methods: Sixty patients with SMA type 2 and 3 (mean age 32.3 years, SD 17.4 years) and 60 age-matched controls filled out questionnaires about impairments of mandibular function. All participants underwent detailed clinical examination to document the mandibular range of motion including maximal mouth opening, bite force, and masticatory function. Results: All mandibular movements, including mouth opening, lateral range of motion, and protrusion of the mandible, were reduced in patients with SMA type 2 and 3 compared to healthy controls (p < 0.001). Maximal bite force was 19% lower in patients than controls, and more in patients with SMA type 2 than type 3. The strongest predictive factor was SMA type for impairment of mandibular range of motion (R2 = 0.82) and weakness of neck muscles for bite force (R2 = 0.47). Conclusions: Reduced mandibular mobility and bite force are common complications in SMA. SMA type and neck muscle strength are important correlates of these complications. We provide further evidence for clinically relevant bulbar involvement in patients with SMA.

Temporomandibular joint involvement in Juvenile Idiopathic Arthritis: reliability and validity of a screening protocol for the rheumatologist

BackgroundIn Juvenile Idiopathic Arthritis (JIA) the temporomandibular joint (TMJ) can be involved leading to pain, dysfunction and growth disturbances of the mandible and associated structures. There may be value to a three minute screening protocol allowing the rheumatologist to detect TMJ involvement systematically. Reliability and validity of the TMJ protocol for detecting TMJ co-morbidity were determined in 74 consecutive JIA patients.MethodsThe assessments of the rheumatologist and of a reference examiner (RE) were compared and validity of the TMJ protocol was established using the disease activity (JADAS-27) as an external reference.ResultsThe internal consistency of the protocol was 0.73 (Cronbach’s alpha). The inter-examiner agreement between the rheumatologist and the RE varied between 0.25 and 0.87 (Cohen’s Kappa). Sensitivity and specificity, with the JADAS “3.8” indicating minimal disease activity, were 0.57 and 0.77 respectively. The area under the curve (AUC) was 0.70. A cut-off value of two positive items was found to be an optimal threshold to select the patients with likely TMJ involvement.ConclusionsThe use of the protocol is feasible in everyday clinical practice. Reliability and validity aspects were satisfactory. The screening protocol for TMJ involvement provides the rheumatologist with systematic and focused TMJ information which relates to the JIA disease activity (JADAS-27).

Painful Arthrogenous Temporomandibular Disorders

Painful temporomandibular joint (TMJ) conditions can be specific and nonspecific. In the diagnostic process, the clinician has first to rule out specific conditions and conditions not related to the