Normative values for mandibular mobility in Scandinavian individuals 4-17 years of age.

Assessment of mandibular mobility is an important part of the clinical oro-facial examination of paediatric and adolescent patients. The aims of the present cross-sectional study were to establish age-related normative values for mandibular mobility in a Scandinavian paediatric and adolescent cohort and to assess the validity of universal cut-off values for lower 'normal' mandibular ranges of motion. A total of 1114 Danish individuals between 4-17 years of age were included. Maximal mouth opening capacity and laterotrusion capacity were assessed, in each individual, according to a standardised measurement protocol. The mean maximal mouth opening capacity gradually increased from 38 mm (SD 6·1 mm) at age 4 to 54·5 mm (SD 6·8 mm) at age 17. No inter-gender difference in maximal mouth opening capacity was observed (P > 0·15). The mean maximal laterotrusion capacity gradually increased from 7·4 mm (SD. 1·1 mm) at age four to 10·1 mm (SD 1·9 mm) at age 17. A statistical significant inter-gender difference of 0·8 mm (SD 0·4 mm) was observed in relation to the total laterotrusion capacity; however, the clinical relevance of this significant difference is questionable. Normative values of mandibular function was established in individuals 4-17 years of age. Our findings oppose the use of a single universal cut-off value for 'normal' range of motion in paediatric and adolescent patients. Instead, we recommend to use the age-related normative values of mandibular range of motion as basis for the assessment of the development of oro-facial function.

Cytokines in healthy temporomandibular joint synovial fluid.

Analysis of temporomandibular joint (TMJ) synovial fluid may elucidate the aetiology of temporomandibular disorders and arthritic conditions, as well as the inflammatory mechanisms involved. Knowledge about healthy synovial fluid is necessary to understand TMJ pathologies. We aimed to quantify the proinflammatory cytokines interleukin (IL)-1ß, IL-2, IL-6 and tumour necrosis factor (TNF), and the anti-inflammatory cytokines IL-10 and interferon (IFN)-γ in healthy TMJ synovial fluid to serve as reference values for future studies on TMJ pathologies. Twenty healthy, young adult volunteers without temporomandibular dysfunction were included. Bilateral synovial fluid samples were obtained using the push-pull technique with hydroxocobalamin described by Alstergren in 1999. Cytokines were quantified with Luminex multiplex assays and compared using nonparametric statistical analysis. No serious adverse effects were reported. Of 40 possible samples, 14 fulfilled the strict sampling criteria and were included in the analysis. Cytokine values (reported as medians with interquartile ranges) were as follows: TNF, 23 (13-37) pg mL(-1) ; IL-2, 1·8 (0-22) pg mL(-1) ; and INF-γ, 10 (0-47) pg mL(-1) . IL-1ß, IL-6 and IL-10 were almost undetectable. In addition, TNF and INF-γ cytokine levels correlated. We demonstrated that TNF was consistently detected and IFN-γ and IL-2 sporadically detected in the TMJ synovial fluid of healthy individuals using the hydroxocobalamin method and a multiplex assay. The cytokines IL-10, IL-1ß and IL-6 were barely detectable in this sample of healthy TMJs.

Donor site morbidity after reconstruction of alveolar bone defects with mandibular symphyseal bone grafts in cleft patients--111 consecutive patients.

The aim of this study was to assess the objective and subjective morbidity after reconstruction of alveolar bone defects with mandibular symphyseal bone grafts in patients with cleft lip and palate. One hundred and eleven patients born between 1995 and 1999, who had undergone chin bone harvesting for alveolar cleft reconstruction in the period from 2000 through 2011, were included. A survey of medical records was conducted. Subjective morbidity after reconstruction was assessed using a questionnaire. Medical records revealed few postoperative incidents; 5.6% reported persistent sensory disturbances in the donor area. Postoperative pain averaged 3.6 ± 2.1 (scale 0-10). The overall satisfaction with the surgical result was 8.7 ± 1.7 (scale 0-10). This study revealed that chin bone harvesting for reconstruction of alveolar defects in patients with cleft lip and palate is a safe and predictable procedure, highly appreciated by the patients, and characterized by only minor postoperative incidents. Patients must be informed of the risk of sensory disturbances in the donor area.

Management of temporomandibular joint arthritis-related orofacial symptoms in juvenile idiopathic arthritis by the use of a stabilization splint.

OBJECTIVES: Temporomandibular joint (TMJ) inflammation in patients with juvenile idiopathic arthritis (JIA) may interfere with optimal joint and muscle function. Orofacial symptoms are common findings in relation to TMJ arthritis. Previous research on management of TMJ arthritis-related orofacial symptoms in patients with JIA has focused on pharmacological treatment modalities without involving physical pain management strategies. The aim of this study was to evaluate changes in orofacial pain and TMJ function after stabilization splint treatment. METHOD: Twenty-eight consecutive patients with JIA and arthritis-related orofacial symptoms (mean age 15.5 years, range 8.2-25 years) were included in this prospective observational study. All patients received stabilization splint treatment. A comparable group of 110 healthy children served as controls for the assessments of TMJ mobility. RESULTS: After splint treatment for 8 weeks, a significant reduction in orofacial pain frequency and intensity was reported, and significant improvement in TMJ function was observed. However, TMJ mobility at follow-up remained significantly reduced when compared to the control group. CONCLUSIONS: The stabilization splint is a safe, reversible, low-cost treatment, and familiar to most dental practitioners. Based on our findings, we propose the implementation of stabilization splint therapy for the treatment of JIA patients with TMJ arthritis-related symptoms.

Smallest detectable differences in clinical functional temporomandibular joint examination variables in juvenile idiopathic arthritis.

OBJECTIVE: Temporomandibular joint (TMJ) arthritis in juvenile patients may interfere with optimal joint function and mouth opening patterns. Clinical assessment of maximal mouth opening capacity, laterotrusion and protrusion is critical to TMJ arthritis diagnosis, treatment choice and evaluation of a therapeutic intervention. The aim of the study was to determine the smallest minimal threshold at which differences in maximal mouth opening capacity, laterotrusion, and protrusion between two consecutive observations can be determined. SETTING AND SAMPLE POPULATION: Department of Orthodontics, University of Aarhus, Denmark. Forty-two consecutive patients with juvenile idiopathic arthritis. MATERIAL AND METHODS: Two experienced dentists used a calibrated metallic ruler to measure maximal mouth opening capacity, laterotrusion, and protrusion. Each measurement was carried out thrice by each observer. Intra- and inter-observer variation and the smallest detectable difference were calculated for each variable. RESULTS: The smallest detectable differences were as follows: maximal mouth opening capacity 4.9 mm, laterotrusion 2.4 mm, and protrusion 2.8 mm (one observer and one measurement). These differences declined when measurements were repeated; maximal mouth opening capacity 3.3 mm, laterotrusion 1.4 mm, and protrusion 1.8 mm (two observers with three measurements each). We found no support for a relationship between measurement variation and patient age, measurement variation and TMJ pain, or between measurement variation and previous/current TMJ arthritis. CONCLUSION: The importance of the implementation of a standardized measurement protocol is emphasized including repeated measurements to reduce the smallest detectable difference.

Condylar lesions in relation to mandibular growth in untreated and intra-articular corticosteroid-treated experimental temporomandibular joint arthritis.

OBJECTIVES: To evaluate condylar lesions in relation to mandibular growth in experimental temporomandibular joint (TMJ) arthritis and to assess the outcome of treating this condition with repeated intra-articular corticosteroid injections (IACIs). METHODS: Forty-two 10-week-old rabbits were randomly divided into four groups. Seven animals served as controls. Experimental TMJ arthritis was induced in five animals which received intra-articular TMJ saline injections. Fifteen animals had TMJ arthritis induced and were left untreated and 15 animals had TMJ arthritis induced and were treated with IACIs one week after each TMJ antigen-challenge procedure. Inter-group growth differences were evaluated from head computerised tomography scans taken at the time of arthritis induction and 12 weeks later. The variables assessed were: progression of condylar lesions (erosions/flattening/osteophytes), mandibular bone volume changes, condylar and sagittal ramus growth. RESULTS: No inter-group differences in the progression of condylar lesions were observed despite reduced mandibular growth in all three experimental groups. The most pronounced unfavourable mandibular growth alterations were observed in the corticosteroid-treated arthritis animals. CONCLUSIONS: No evidence was found in support of a relation between reduced mandibular growth and condylar lesions. We propose that: 1) condylar lesions are not the only causative factor of reduced mandibular growth in experimental TMJ arthritis, and 2) repeated IACIs have a very unfavourable impact on mandibular growth in experimental TMJ arthritis - treatment is more detrimental to mandibular growth than the TMJ arthritis itself.

Contrast-enhanced MRI compared to histological findings in the temporomandibular joint of antigen-induced arthritis in young rabbits.

OBJECTIVE: To study the correlation between histological findings and Magnetic Resonance Imaging (MRI) findings in experimentally induced arthritis in the temporomandibular joint (TMJ) of growing rabbits and to study the effect of intraarticular corticosteroid injections. METHODS: Arthritis was induced by ovalbumin in the left TMJ of 44 pre-sensibilized rabbits. Nine animals died during this procedure. Eight of the remaining animals with induced arthritis were treated with intraarticular corticosteroid injections one week after induction of arthritis. Twelve rabbits served as controls. MRI enhanced with Gadolinium-DTPA was performed on all animals 1 to 2 weeks after induction of arthritis and again before sacrifice and the degree of enhancement was calculated. Histology of the condyle was performed and degree of villous hyperplasia, synovial thickness, infiltration of inflammatory cells and pannus was graded. RESULTS: TMJ arthritis was successfully induced in the rabbits and was verified by enhancement of the MRI and by histological changes one week after the induction. Joints treated with intraarticular corticosteroid injections revealed complete inhibition of the inflammation. CONCLUSION: Enhancement of MRI in antigen-induced arthritis in the TMJ associated well with inflammatory changes shown histologically. An intraarticular corticosteroid injection prevents the initial inflammatory response in experimentally induced TMJ arthritis.

Contrast enhanced magnetic resonance imaging as a method to diagnose early inflammatory changes in the temporomandibular joint in children with juvenile chronic arthritis.

OBJECTIVE: Recent studies have stressed early diagnosis of temporomandibular joint (TMJ) involvement in children with juvenile chronic arthritis (JCA) to initiate treatment before destruction of the condylar head and growth alterations take place. TMJ involvement is often asymptomatic, but studies with contrast enhanced magnetic resonance imaging (MRI) in other joints have shown that it is possible to detect the early inflammatory changes. METHODS: Thirty TMJ in 15 children with newly diagnosed JCA (mean age 12.0 years) were examined clinically, with radiographs and with MRI enhanced with gadolinium diethylene thiamine pentaacetic acid (Gd-DTPA). A control group of 10 healthy children (mean age 11.5 yrs) were examined clinically and with MRI. The MRI variables included T1 weighted images before and after administration of Gd-DTPA with and without fat suppression. RESULTS: MRI enhanced with Gd-DTPA indicated inflammatory activity in 87% of the patients. Conventional MRI without contrast medium proved to be insignificant in diagnosing early inflammatory changes. CONCLUSION: Enhanced MRI is very efficient in diagnosing early inflammatory changes of the TMJ and is a more sensitive method than the clinical examination and radiographs.

Approximal plaque pH following topical applications of standard buffers in vivo.

In this study, the null hypothesis was tested that topical application of standard buffer solutions, pH 7.00 and pH 4.01, to 4-day-old plaque deposits accumulated in situ causes the plaque to attain the pH values of the buffer solutions applied. Following a 4-day abstention from all oral hygiene procedures, the plaque pH of four interdental sites in each of 5 volunteers was measured at resting state and following topical applications of buffers pH 7 and pH 4. Later the same day plaque pH was measured following rinses with the buffers. Topical application of buffer pH 7 caused a plaque pH increased from a mean value of 6.40 to 6.59 within 30 s, while buffer pH 4 caused plaque pH to drop to a mean value of 5.11. Rinsing with buffers caused plaque pH to increase to 6.50 (buffer pH 7) and to drop to 4.92 (buffer pH 4). Statistical analysis of the results led to rejection of the null hypothesis. The results thus indicated that the validity of the in situ approach of calibration of plaque-covered indwelling electrodes may be questioned.

Accuracy and precision in vitro of Beetrode microelectrodes used for intraoral pH measurements.

The accuracy and precision of 12 different microelectrodes were assessed through a series of pH recordings of buffer solutions with known pH values. Some electrodes were quite accurate, yielding an average deviation of recordings from true values of about 0.05 pH units, while other electrodes yielded average deviations of up to 0.20 pH units. The precision of the electrodes also varied between electrodes. While all recordings were within 0.15 pH units from the true values for some electrodes, other electrodes showed a marked dispersion with less than 25% of the recordings being within 0.15 pH units from true values. For some electrodes accuracy depended on true pH values, while no such dependency was noted with respect to the precision of the electrodes tested. Both accuracy and precision may be impaired when pH recordings are made on solutions with pH values outside the pH range encompassed by the calibration buffers. Our results demonstrate that the accuracy and precision of these microelectrodes cannot be considered fixed and known parameters. Electrodes should therefore be checked prior to clinical use, and electrodes with low accuracy and precision should be excluded from further use.