Scand J Rheumatol 2014;43:137–145
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Management of temporomandibular joint arthritis-related orofacial symptoms in juvenile idiopathic arthritis by the use of a stabilization splint P Stoustrup1, KD Kristensen1, A Küseler1,3, C Verna1, T Herlin2, TK Pedersen1,3
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1 Section of Orthodontics, Aarhus University, 2Department of Paediatrics, Aarhus University Hospital, and 3Department of Maxillofacial Surgery, Aarhus University Hospital, Aarhus, Denmark
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.
Temporomandibular joint (TMJ) inflammation and degenerative joint alterations in patients with juvenile idiopathic arthritis (JIA) may interfere with optimal joint and muscular function and lead to mandibular growth disturbances (1–5). The presence of orofacial symptoms and functional impairments of the TMJ and the surrounding soft tissue are seen in 26–74% of JIA patients with TMJ arthritis, and disease duration correlates with craniofacial symptoms and dysfunction (3, 6). The main complaints associated with TMJ arthritis are reduced maximal opening capacity and transient pain during maximal mouth opening and mastication, in addition to TMJ morning stiffness (3, 4, 6–8). The symptoms most often involve both the TMJ and the masseter muscle areas; self-reported symptoms solely from the TMJ region are more rare (7). Therefore, TMJ arthritis must be recognized as involving more than the TMJ itself. Management is important because TMJ arthritis-induced orofacial symptoms may be disabling and interfere with daily life activities (3, 6, 9) and because optimal TMJ and muscular function are crucial to normal craniofacial development in children and adolescents (10).
Peter Stoustrup, Section of Orthodontics, Aarhus University, Vennelyst Boulevard 9-11, 8000 Aarhus, Denmark. E-mail: [email protected]
TMJ arthritis is a subdiagnosis of the more general umbrella term temporomandibular disorders (TMDs), and TMJ arthritis symptoms are comparable to those of other conditions covered by the general term (11, 12). The flat, acrylic stabilization splint has been important in the management of TMDs and orofacial symptoms for decades (13, 14), even though its mode of action while positioned on the teeth in the upper or lower jaw remains incompletely understood. Suggested mechanisms include repositioning of the condylar head in the TMJ, preventing high pressure on the joint surfaces, transient decrease in masticatory muscle activity, reduced bruxism, balanced occlusion, awareness of the cognitive-behavioral aspect of orofacial pain, and a placebo effect (15, 16). The stabilization splint in TMD treatment is controversial, with insufficient evidence for or against its use when compared to other active treatment modalities. However, some data suggest that stabilization splint therapy can alleviate TMD-related orofacial pain in adults and adolescents when compared to no active intervention (13–16). The effect of this therapy has not previously been evaluated in patients with JIA and TMJ arthritis-related orofacial symptoms. Because these symptoms are comparable to those of other TMDs described in the literature as possibly amenable to splint therapy, we hypothesized that stabilization splint therapy could alleviate TMJ
Accepted 25 July 2013 © 2014 Informa Healthcare on license from Scandinavian Rheumatology Research Foundation DOI: 10.3109/03009742.2013.830146
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arthritis-related orofacial pain and improve orofacial function despite not targeting inflammation. The present prospective observational study involved a consecutive cohort of patients with JIA and TMJ arthritisrelated orofacial symptoms undergoing stabilization splint therapy. The aims were to evaluate changes in sensory-discriminative components of self-reported orofacial symptoms (pain frequency, intensity, and localization, and main complaints) and changes in orofacial function when compared to a control group of age- and sex-matched healthy individuals.
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Participants A group of 33 consecutive patients with JIA and TMJ arthritis-related orofacial symptoms were identified as candidates for study inclusion (Table 1). All patients received examination and treatment of their TMJ conditions at the Section of Orthodontics, Aarhus University, Denmark, between September 2010 and July 2012. The initial TMJ arthritis diagnosis was based on a general assessment of the radiological findings obtained by cone beam computed tomography (CBCT) radiological evaluation in
Table 1. Cohort characteristics. TMJ arthritis group Control group (n ¼ 28) (n ¼ 110) Females, n (%) Mean age, years (range) TMJ involvement, individuals Unilateral Bilateral JIA diagnosis, individuals Oligoarticular extended Oligoarticular persistent Polyarticular RF negative Polyarticular RF positive Systemic Psoriatic Enthesitis related Unclassified Medication NSAID Methotrexate IACI * Systemic steroid Biologics No medication Combination of two drugs Combination of three drugs Combination of four drugs
26 (93) 15.5 (8.2–25)
100 (91) 14.9 (8.4–18)
12 16
– –
6 6 4 4 1 2 1 4
– – – – – –
10 13 2 0 10 6 8 1 1
– – – – – – – – –
TMJ, Temporomandibular joint; JIA, juvenile idiopathic arthritis; RF, rheumatoid factor; NSAID, non-steroidal anti-inflammatory drug; IACI, intra-articular corticosteroid. * Intra-articular TMJ steroid injection within the past year (not within the 4 months prior to inclusion in this study).
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combination with clinical findings obtained from our standardized orthodontic clinical examination protocol, described previously (7, 17). Radiological pathological findings were defined as conditions deviating from the normal TMJ outline on two-dimensional CBCT cuts (e.g. flattening, erosive changes, sclerosis, and osteophytes). The initial TMJ arthritis diagnosis was made based on a clinical impression; however, the diagnosis was independent of the presence of radiological pathological findings and/or orofacial symptoms. However, in this study, the presence of orofacial symptoms was a specific inclusion criterion. No contrast-enhanced magnetic resonance imaging (MRI) procedures were used for diagnosis of TMJ arthritis in the patients in this study because TMJ arthritisrelated orofacial pain, and not inflammation, was the target of the intervention.
Inclusion and exclusion criteria Inclusion and exclusion criteria were defined prior to study initiation. Inclusion criteria were: (i) JIA diagnosis according to the criteria of the International League of Associations for Rheumatology (18); (ii) the presence of TMJ arthritis-related orofacial symptoms based on our regular standardized clinical examination and radiological evaluation; and (iii) age 8 years and cognitively capable of understanding the standardized questionnaire and the concept of the visual analogue scale (VAS). Exclusion criteria were: (i) failure to comply with the instruction given on the use of the splint; (ii) ongoing treatment with functional orthopaedic appliances; (iii) treatment with intra-articular TMJ steroid injection or change in systemic medication within 4 months prior to the study; (iv) TMJ hypermobility based on a general clinical assessment; and (v) failure to attend the follow-up outcome evaluation less than 180 days after splint therapy initiation. The stabilization splint therapy complies with the rules of the Danish Board of Health for clinical paediatric dental treatment. The Danish Data Protection Agency approved handling of the confidential data, and the Danish Ministry of Health approved the use of the patient files.
Control group A control group of 110 individuals comparable for age and sex was included in the study to enable a comparison in function between patients with TMJ arthritis-related orofacial pain and healthy individuals. Data concerning mandibular function were obtained from the patient files of 110 healthy age- and sex-matched individuals from the public dental clinics in the council of Syddjurs, Denmark. These functional variables were assessed using a standardized measurement protocol identical to the one used in this study. None of the patients in the control group received splint treatment or were diagnosed with any orofacial symptoms.
Splint against orofacial pain
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Stabilization splint fabrication The stabilization splint used in this study was fabricated from impressions of the upper and lower dental arches and a recording of the centric position. From a clinical assessment, the centric position was defined as the optimal position of the mandible relative to the skull where the masticatory muscles are in their most relaxed and least strained position. A stabilization splint was fabricated and positioned in the mandible on the mandibular dentition. The splint was fabricated as a ‘flat’ splint with no impressions for occluding guidance. Occlusal and articular adjustments were made to the splint after fabrication to obtain a stable occlusal relationship with uniform contacts between the splint and the maxillary teeth throughout the range of the splint (Figure 1). Patients were instructed to use the splint during sleeping hours, at a minimum; further use was recommended in some patients based on individual clinical assessment. The use of the splint was individualized and based on the nature of their pain complaints. Additionally, participants received brief information about TMJ pathology and instruction in the correct use of the stabilization splint. Splint treatment was planned to continue until noticeable reduction or resolution of the orofacial pain was seen; at this point the use of the splint was gradually reduced based on individual recommendations. Patients were also advised to save the splint and use it for potential future episodes of TMJ arthritis-related pain. The start time of splint therapy was defined as T1. A follow-up visit was arranged 8 weeks after splint therapy began, referred to as T2.
Pain variables At T1 and T2, all patients completed a standardized questionnaire concerning orofacial pain assessment within the past 7 days, covering orofacial pain frequency, average pain intensity, pain-eliciting factors (‘In which situations do you feel the pain?’), and localization of pain on a schematic drawing illustrating the head and the neck. Pain frequency. Patients were asked to report the frequency of their orofacial symptoms on a five-point Likert scale: (i) pain less than once a week; (ii) pain 1–3 times a week; (iii) pain 4–6 times a week; (iv) pain several times a day; and (v) pain all the time.
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Pain intensity. The patients were asked to assess the average pain intensity on a non-verbal VAS of 100 mm, where the left extreme represents ‘no pain’ and the right extreme represents the ‘worst imaginable pain’. Pain index. To combine the aspects of orofacial frequency and intensity, this composite variable was created, calculated as the pain frequency multiplied by the pain intensity, with a score range between 0 and 500.
Clinical examination of functional variables At T1 and T2, all patients underwent a clinical examination. A standardized measurement protocol was used for the assessment of the maximal mouth opening capacity and laterotrusion capacity. The laterotrusion capacity was defined as the total amount of mandibular excursion from the leftmost side to the rightmost side (the sum of the right and the left laterotrusion movement capacities). All patients were carefully instructed in the correct performance of the specific manoeuvres before the measurements were made. Maximal mouth opening capacity and maximal laterotrusion capacity were measured with a calibrated regular 150mm metallic ruler. The patients were instructed to execute the maximal laterotrusion with a consistent contact between teeth in the upper and lower jaws. The horizontal overjet, vertical overbite, and any midline deviation were assessed before the measurements and accounted for in the measurement result. Additionally, pain on palpation of the masticatory muscles and the TMJs was recorded together with the assessment of clinical signs of internal derangement (e.g. crepitus, anterior discus displacement with or without reduction).
Statistics Pre- and post-treatment functional outcome variables were compared to the values in a control group of ageand sex-matched healthy individuals. Intra-group differences in pain variables and functional variables between T1 and T2 were assessed by paired Student’s t-tests after the data were tested for normal distribution. Changes in the categorical data concerning pain frequency were analysed statistically using a Wilcoxon matched-paired rank test for the evaluation of intra-group differences between
Figure 1. Frontal and occlusal view of a stabilization splint positioned in the lower jaw. The splint presented here is without incisal acrylic coverage.
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T1 and T2. The values of the functional variables at T1 and T2 were compared to the values of the age-matched healthy individuals by the use of student’s independent t-tests. Fisher’s two-tailed exact test was used to assess the changes in pain on palpation and clinical findings between T1 and T2. A p-value < 0.05 was considered significant. Correlation between maximal mouth opening capacity and the pain index was assessed by calculation of Pearson’s correlation coefficient.
Results
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Patients and control group Of the 33 identified candidates, 28 patients complied with the inclusion criteria (mean age 15.5 years; range 8.2–25 years; girls n ¼ 26; boys n ¼ 2). The five patients who did not comply with the inclusion criteria were excluded from the study for the following reasons: failure to comply with the instruction given on the use of the splint (n ¼ 2), a T2 follow-up evaluation more than 180 days after the splint therapy was initiated (n ¼ 2), and a change in general medication between T1 and T2 (n ¼ 1). Of the 28 included patients, arthritis-related orofacial symptoms were seen in relation to 44 TMJs. The majority of patients were diagnosed with either oligoarticular or polyarticular JIA subtypes. Further cohort characteristics are described in Table 1. The mean follow-up time between T1 and T2 was 56 days (SD ¼ 34.2). The functional outcome variables of the included patients were compared to 110 age- and sexmatched healthy controls with a mean age of 14.9 years (range 8.4–18 years, 100 girls and 10 boys).
statistically significantly reduced to a pain frequency score of 2.5 (median 2), a VAS pain intensity of 40.5 mm, and a pain index of 106. Further information is listed in Table 2 and intra-individual changes are illustrated in Figure 2A–D. At T2, four patients reported a substantial increase in their pain index scores, and four reported a minor increase in pain index scores between T1 and T2 (Figure 2C); the rest of the cohort (n ¼ 20) experienced minor to substantial reduction in pain index scores during this period (Figure 2D). The three patients with the highest T1 pain index scores all reported a significant reduction in this outcome variable at the follow-up evaluation (Figure 2C). The relative changes in pain index scores revealed that 15 of the group of 28 patients reported at least a 50% reduction in this primary pain outcome variable between T1 and T2 (Figure 2D). At T1, the majority of patients experienced selfreported orofacial symptoms: TMJ symptoms in 75% and 57% (right and left sides, respectively) and masseter muscle symptoms in 50% and 54% (right and left sides, respectively) during mastication (n ¼ 14) and maximal mouth opening procedures (n ¼ 6), in addition to TMJ morning stiffness (n ¼ 5) (Figure 3). At T2, a reduction in the number of patients experiencing symptoms from the TMJ (60% and 54%, right and left sides, respectively) and masseter muscle (35% and 39%, right and left sides, respectively) was seen (Figure 3). No change in the number of patients reporting symptoms during mastication (n ¼ 13), maximal mouth opening (n ¼ 7), TMJ loading (n ¼ 4), or morning stiffness (n ¼ 5) was seen between T1 and T2. However, in contrast to T1, no patient reported ‘pain all day long’ at T2. Figure 3 illustrates the total number of complaints at T1 and T2.
Pain variables and main complaints Before initiating the splint treatment (T1), the included patients reported the following values for pain: a pain frequency mean score of 3.1 (median score 3 equivalent to pain 4–6 times a week), a VAS pain mean intensity of 55.2 mm, and a pain index mean score of 178.6 (Table 2). At the T2 follow-up examination, all of these variables were
Clinical examination Figure 4 presents the results of the clinical examination at T1 and T2. A tendency towards a statistically significant reduction in the number of patients without pain on palpation and clinical findings at T2 (p ¼ 0.051) was observed; however, no statistical significant changes were observed in any of the categories between T1 and
Table 2. Pain and functional measures in JIA patients with TMJ arthritis receiving stabilization splint therapy.
Pain Pain frequency* Pain intensity (mm) Pain index Function Mouth opening (mm) Laterotrusion (mm)
Before treatment (T1)
After treatment (T2)
Difference (SD)
95% CI
p value
3.1 55.2 178.6
2.5 40.5 106.9
NA –14.8 (17.6) –71.7 (109.2)
NA –21.6 to –7.9 –11.4 to –29.4
0.0423 0.0001 0.0017
41.4 14.8
45.3 16.6
3.9 (5.2) 1.8 (3.8)
1.9–5.9 0.3–3.3
0.0005 0.0234
JIA, Juvenile idiopathic arthritis; TMJ, temporomandibular joint; SD, standard deviation; CI, confidence interval; NA, not applicable * Categorical data where patients have graded the frequency of orofacial pain from 1 to 5 and the mean scores at T1 and T2 are shown.
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Splint against orofacial pain
A 100
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Pain intensity p < 0.05
Pain frequency p < 0.05
B All the time
VAS score (mm)
80 Several times daily 60 4-6 times weekly 40 1-3 times weekly 20 < Week Pre treatment T1
Post treatment T2
Pre treatment T1
Pain Index p < 0.05
C
D
500
Post treatment T2
Relative change in Pain-index score T1 to T2
Relative change from T1 to T2/%
100
400 Pain Index
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0
300 200 100 0 Pre treatment T1
Post treatment T2
75 50 25 0 –25 –50 –75 –100
Figure 2. Outcome measures of pain. Horizontal dotted lines illustrate the 95% confidence intervals, and descending dotted line illustrates the mean decrease in pain intensity between T1 and T2. (A) Pain intensity on a visual analogue scale (VAS). (B) Pain frequency. (C) Pain index; composite pain variable combining the aspects of pain intensity and pain frequency (intensity frequency). (D) Relative reduction in pain index score between T1 and T2. The ‘zero’ on the y axis indicates ‘no relative change’. Note that more than half of the group receiving stabilization splint treatment experienced a reduction of more than 50%.
T2. Pain on palpation of both the TMJ and the masticatory muscles was the most frequent finding at T1 (n ¼ 10). In addition to TMJ and masticatory muscle pain on palpation, seven patients were diagnosed with at least one additional TMJ clinical finding: click (n ¼ 7), obviously reduced TMJ translation (n ¼ 4), anterior disc displacement without reduction and locking (n ¼ 1), and crepitation (n ¼ 3). At T1, pain on palpation either solely from the TMJ (n ¼ 2) or the masticatory muscles (n ¼ 1) was rare. At T2, seven patients (25%) had no pain on palpation or clinical findings, compared to one patient at T1 (4%). The number of patients with pain solely from the masticatory muscles increased from one to four patients between T1 and T2; however, this could be explained by the fact that six out of the 10 patients with ‘TMJ and muscle pain’ on palpation at T1 changed groups. At T2, three of these patients switched to the group with only masticatory muscle pain, and three had no pain on palpation or other clinical findings (Figure 4).
Functional variables Table 2 presents the changes in mean values of maximal mouth opening capacity and laterotrusion capacity between T1 and T2. Both maximal mouth opening capacity and maximal laterotrusion capacity significantly improved between T1 and T2. The mean follow-up changes were maximal mouth opening capacity of 3.9 5.2 mm and laterotrusion capacity of 1.8 3.8 mm. Table 3 presents the functional variables when compared to healthy and age-matched controls. Despite significant positive changes in TMJ function between T1 and T2 among treated patients, the TMJ function remained significantly reduced when compared to age- and sexmatched controls.
Correlation between function and pain At T1, no correlation between maximal mouth opening capacity and pain index score was observed (r ¼ –0.14).
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P Stoustrup et al Figure 3. (A) Main complaints before (T1) and after (T2) stabilization splint treatment. Grey bars illustrate T1 complaints, and black bars T2 complaints. The term ‘loading of the joint’ represents situations in which external load has been applied to the joint (e.g. when the head is placed on a pillow). (B) Face maps illustrating the relative localization of orofacial symptoms before (T1) and after (T2) treatment. The areas of the temporal muscle, the temporomandibular joint (TMJ), and the masseter muscle have been labelled.
Self-reported Orofacial Pain
A
T1 T2
TMJ morning stiffness Mastication Loading of the joint Max. mouth opening All day long When I am tired Headache Talking No pain No reported symptoms
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0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Number of patients T1 right
B
T1 left
11%
Temporalis area Temporomandibular joint
0%
11%
75%
57%
Masseter area
50%
54% 0%
0%
14%
0%
0%
4%
4%
11%
60%
0%
0%
0%
35%
39%
0%
0%
T2 left
T2 right
case of TMJ arthritis and TMDs in general, these goals have proved elusive. The main findings of this study are that, after splint therapy for TMJ arthritis-related orofacial symptoms in patients with JIA, a significant symptomatic relief was reported in terms of reduced orofacial pain frequency and intensity without substantially changing the pain locations or the nature of the self-reported complaints. Total resolution of orofacial pain was rare and the majority of patients had sustained self-reported
There also was no correlation between increased maximal mouth opening capacity and improvement in pain index score between T1 and T2 (r ¼ –0.023). Discussion The principal treatment goals for patients with TMJ arthritis are to achieve resolution of pain if present and normalize TMJ function and growth. However, in the
Pain on palpation and clinical findings T1 (F = 1.00) T2 (F = 0.25)
only TMJ pain only maslcalory muscle pain
(F = 1.00)
only clinical findings*
(F = 0.12)
TMJ and muscle pain (F = 1.00)
TMJ and muscle pain and clinical findings (F = 1.00)
Muscle pain and clinical findings TMJ pain and clinical findings
(F = 1.00) (F = 0.051)
None 0
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1 2 3 4 5 6 7 8 Number of patients
9 10 11
Figure 4. Pain on palpation and clinical findings. Grey bars illustrate T1 complaints, and black bars T2 complaints. Clinical findings represent, for example, temporomandibular joint (TMJ) click, obviously reduced TMJ translation, anterior discus displacement without reduction, locking, or crepitation. p-values are from Fisher’s exact test, twotailed.
Splint against orofacial pain
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Table 3. Functional outcome measures in JIA patients with TMJ arthritis receiving stabilization splint therapy in comparison to age- and sex-matched controls.
Before treatment (T1) Mouth opening (mm) Translation (mm) After treatment (T2) Mouth opening (mm) Laterotrusion (mm)
JIA group
HC
Difference (SD)
95% CI
p value
41.4 14.8
52 19.4
10.6 (10.9) 4.5 (6.2)
6.4–14.9 2.2–6.9
> 0.0000 0.0006
45.3 16.6
52 19.4
6.7 (10.1) 2.8 (4.7)
2.8–10.6 1–4.6
0.0015 0.0040
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JIA, Juvenile idiopathic arthritis; TMJ, temporomandibular joint; HC, healthy controls; SD, standard deviation; CI, confidence interval.
complaints and clinical findings at T2; however, more than half of the patients in the study group experienced at least a 50% reduction in pain index scores, pointing to a beneficial reduction in intensity and/or frequency. In this context it is important to note that the changes in pain scores revealed a sustained amount of actual pain after splint treatment had been conducted, indicating a large variation in the inter-patient response to this treatment. Based on our findings, it is our general impression that orofacial symptoms fluctuate over time and that the stabilization splint has a palliative (not curative) effect on the orofacial symptoms. In addition, even though patients had significant improvement in TMJ function at follow-up, this was still significantly reduced compared to that of healthy age- and sex-matched controls. We observed no correlation between the maximal mouth opening capacity and the level of orofacial symptoms, indicating that high pain scores are not directly reflected in reduced TMJ function in these patients. Previous research in this area has focused on a pharmacological approach using intra-articular TMJ steroid injections for MRI-verified inflammation (19–23). The splint therapy described here involves a functional physiotherapeutic management strategy against TMJ arthritis-related orofacial symptoms independent of TMJ inflammation status. A direct comparison between previous and current findings would be interesting but potentially misleading because of differences in management strategy (physical vs. pharmacological), baseline cohort characteristics, and treatment indications. It is noteworthy, however, that the functional improvements identified here are comparable to, and even exceed, the level of functional improvement described in studies reporting the effect of intra-articular TMJ steroid intervention (19, 21–23). The pain localizations and main complaints identified in the current work are comparable to previous descriptive studies on TMJ arthritis symptoms in patients with JIA (3, 6, 7). The orofacial pain may not be caused directly by the arthritic condition but rather as a secondary phenomenon caused by chronic joint alterations that follow the TMJ arthritis. In this context it is therefore important to emphasize that stabilization splint therapy is not a treatment against TMJ inflammation but a treatment aimed at the related orofacial pain issues that are seen in some patients with JIA and TMJ arthritis.
Because of the fluctuation of TMJ arthritis-related symptoms in patients with JIA and the limited number of patients in this study, it is difficult to draw general conclusions based on our clinical findings; however, we can hypothesize that stabilization splint therapy may reduce the intensity and frequency of TMJ arthritis-related symptoms without changing the number of other complaints (TMJ morning stiffness, pain on mastication, loading of the joint, pain on maximal mouth opening) in the group of treated patients. We note that more than half of the patients reported a 50% reduction in pain at post-treatment followup and that a quarter of the patients experienced no pain on palpation or other clinical findings at T2. Previous studies dealing with TMJ arthritis interventions in patients with JIA did not quantify pain, using VAS for example, and comparisons between our related findings and studies on pain management in this patient population are not possible. However, the mean 15-mm improvement we identified in VAS score for pain intensity at follow-up exceeded both the smallest detectable difference within this assessment technique and values for minimal clinically relevant differences in self-reported pain assessment in children (7, 24). By contrast, the functional improvements we identified did not exceed the smallest detectable difference (i.e. the variation within the measurement technique) despite significant differences in maximal mouth opening capacity and laterotrusion capacity between T1 and T2 (25). This result agrees with previous findings in patients receiving pharmacological intervention against TMJ arthritis-related symptoms, in which improvements in mandibular function were not large enough to exceed the smallest detectable difference within the measurement technique (23, 25). The splint therapy has a different aim of action than intraarticular TMJ steroid intervention. The physiological and placebo effects of the stabilization splint are unknown but are unlikely to be anti-inflammatory (14, 15, 26). In terms of TMJ arthritis, only a limited association exists between clinical signs and symptoms and MRI-verified signs of TMJ inflammation in patients with JIA (19, 27, 28). We have therefore previously suggested a dual approach to TMJ arthritis-related orofacial symptoms that combines antiinflammatory therapies with other pain management strategies such as a stabilization splint treatment (7).
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Stabilization splint intervention is reversible, conservative, safe, familiar, and low cost, with manufacture requiring only limited specialized dental education, and many general dental practitioners are familiar with this treatment modality (13, 14). This therapy is the primary intervention in our department when patients are diagnosed with TMJ arthritis-related orofacial symptoms. An advantage is that it can serve as a singletreatment modality or can be used in combination with other management strategies such as intra-articular TMJ steroid injection, physiotherapy, and/or systemic antiinflammatory intervention. Our study had some limitations. Neither patients nor assessors were blinded to treatment or outcome variables, the patient numbers were limited, and we had no placebo group with TMJ arthritis-related symptoms because of the observational design. Without a placebo group, we cannot show a cause–effect relationship between the use of the stabilization splint and the symptomatic relief and functional improvements identified. Therefore, we cannot exclude the possibility that increased awareness focusing on the orofacial symptoms of the patients could have elicited a placebo effect in combination with the natural fluctuating course of the orofacial symptoms and contributed to the improvements (26). However, despite the lack of a placebo group, our preliminary findings suggest a beneficial effect of the splint therapy. A potential source of bias was the design chosen for the study; because we wanted to assess the efficacy of the stabilization splint in patients who were compliant to the predefined treatment protocol, we applied a ‘per-protocol’ design and not an ‘intention-to-treat’ design. We acknowledge the possibility that excluding the patients violating the treatment protocol from the final analysis could maximize the described effect. This is because treatment compliance may be compromised if the initial pain reduction effect is not in agreement with the self-perceived ‘burden’ of the treatment. Future studies in accordance with evidence-based standards including a placebo-treated group of patients and with ‘intention-to-treat’ analysis designs are needed to evaluate the true cause-and-effect relationship of splint therapy in patients with JIA and TMJ arthritis. The study’s strengths include its standardized and specific treatment protocol, prespecified outcome variable evaluation protocol, and the inclusion of an age- and sex-matched control group. Additionally, in contrast to previous literature on TMJ arthritis management in patients with JIA, the current work involved a more comprehensive evaluation of various aspects of orofacial symptoms (e.g. intensity, frequency, localization, and main complaints) in accordance with contemporary clinical consensus guidelines on pain assessment in paediatric patients (29, 30). However, not all of these clinical variables (e.g. pain index) have yet been validated in this group of patients, which is a potential weakness in the standardized examination carried out.
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Conclusions The current results provide evidence to support the hypothesis that stabilization splint therapy may reduce the intensity and frequency of TMJ arthritis-related symptoms and improve mandibular function. The stabilization splint involves a different management aspect from previous studies dealing with pharmacological approaches to TMJ arthritis-related orofacial symptoms and is reversible, conservative, safe, familiar to most dentists, and low cost. Based on our findings, we propose the implementation of stabilization splint therapy in the treatment of JIA patients with TMJ arthritis-related symptoms. Acknowledgements We thank the entire staff of the rheumatic team at the Section of Orthodontics, Aarhus University, Denmark, and the employees of Syddjurs Council Dental Service for their collaboration in this project. We also thank graphic designer Nikolai Lander for assistance with the illustrations.
References 1. Arvidsson LZ, Flato B, Larheim TA. Radiographic TMJ abnormalities in patients with juvenile idiopathic arthritis followed for 27 years. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2009;108:114–23. 2. Arvidsson LZ, Fjeld MG, Smith HJ, Flato B, Ogaard B, Larheim TA. Craniofacial growth disturbance is related to temporomandibular joint abnormality in patients with juvenile idiopathic arthritis, but normal facial profile was also found at the 27-year follow-up. Scand J Rheumatol 2010;39:373–9. 3. Bakke M, Zak M, Jensen BL, Pedersen FK, Kreiborg S. Orofacial pain, jaw function, and temporomandibular disorders in women with a history of juvenile chronic arthritis or persistent juvenile chronic arthritis. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2001;92:406–14. 4. Pedersen TK, Kuseler A, Gelineck J, Herlin T. A prospective study of magnetic resonance and radiographic imaging in relation to symptoms and clinical findings of the temporomandibular joint in children with juvenile idiopathic arthritis. J Rheumatol 2008;35: 1668–75. 5. Twilt M, Schulten AJ, Nicolaas P, Dulger A, Suijlekom-Smit LW. Facioskeletal changes in children with juvenile idiopathic arthritis. Ann Rheum Dis 2006;65:823–5. 6. Engstrom AL, Wanman A, Johansson A, Keshishian P, Forsberg M. Juvenile arthritis and development of symptoms of temporomandibular disorders: a 15-year prospective cohort study. J Orofac Pain 2007; 21:120–6. 7. Stoustrup P, Kristensen KD, Verna C, Kuseler A, Herlin T, Pedersen TK. Orofacial symptoms related to temporomandibular joint arthritis in juvenile idiopathic arthritis: smallest detectable difference in selfreported pain intensity. J Rheumatol 2012;39:2352–8. 8. Muller L, Kellenberger CJ, Cannizzaro E, Ettlin D, Schraner T, Bolt IB, et al. Early diagnosis of temporomandibular joint involvement in juvenile idiopathic arthritis: a pilot study comparing clinical examination and ultrasound to magnetic resonance imaging. Rheumatology (Oxford) 2009;48:680–5. 9. Leksell E, Ernberg M, Magnusson B, Hedenberg-Magnusson B. Orofacial pain and dysfunction in children with juvenile idiopathic arthritis: a case-control study. Scand J Rheumatol 2012;41:375–8.
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Splint against orofacial pain 10. Pedersen TK, Norholt SE. Early orthopedic treatment and mandiblar growth of children with temporomandibular joint abnormalities. Semin Orthod 2011;17:235–45. 11. Cairns BE. Pathophysiology of TMD pain – basic mechanisms and their implications for pharmacotherapy. J Oral Rehabil 2010;37:391–410. 12. List T, Wahlund K, Wenneberg B, Dworkin SF. TMD in children and adolescents: prevalence of pain, gender differences, and perceived treatment need. J Orofac Pain 1999;13:9–20. 13. Al-Ani MZ, Davies SJ, Gray RJ, Sloan P, Glenny AM. Stabilisation splint therapy for temporomandibular pain dysfunction syndrome. Cochrane Database Syst Rev 2004;(1):CD002778. 14. Al-Ani Z, Gray RJ, Davies SJ, Sloan P, Glenny AM. Stabilization splint therapy for the treatment of temporomandibular myofascial pain: a systematic review. J Dent Educ 2005;69:1242–50. 15. List T, Axelsson S. Management of TMD: evidence from systematic reviews and meta-analyses. J Oral Rehabil 2010;37:430–51. 16. Wahlund K. Temporomandibular disorders in adolescents. Epidemiological and methodological studies and a randomized controlled trial. Swed Dent J Suppl 2003;(164):2–64. 17. Stoustrup P, Kuseler A, Kristensen KD, Herlin T, Pedersen TK. Orthopaedic splint treatment can reduce mandibular asymmetry caused by unilateral temporomandibular involvement in juvenile idiopathic arthritis. Eur J Orthod 2013;35:191–8. 18. Petty RE, Southwood TR, Manners P, Baum J, Glass DN, Goldenberg J, et al. International League of Associations for Rheumatology classification of juvenile idiopathic arthritis: second revision, Edmonton, 2001. J Rheumatol 2004;31:390–2. 19. Arabshahi B, Dewitt EM, Cahill AM, Kaye RD, Baskin KM, Towbin RB, et al. Utility of corticosteroid injections for temporomandibular arthritis in children with juvenile idiopathic arthritis. Arthritis Rheum 2005;52:3563–9. 20. Cahill AM, Baskin KM, Kaye RD, Arabshahi B, Cron RQ, Dewitt EM, et al. CT-guided percutaneous steroid injection for management of inflammatory arthropathy of the temporomandibular joint in children. AJR Am J Roentgenol 2007;188:182–6. 21. Ringold S, Torgerson TR, Egbert MA, Wallace CA. Intraarticular corticosteroid injections of the temporomandibular joint in juvenile idiopathic arthritis. J Rheumatol 2008;35:1157–64.
145 22. Stoll ML, Good J, Sharpe T, Beukelman T, Young D, Waite PD, et al. Intra-articular corticosteroid injections to the temporomandibular joints are safe and appear to be effective therapy in children with juvenile idiopathic arthritis. J Oral Maxillofac Surg 2012;70:1802–7. 23. Stoustrup P, Kristensen KD, Verna C, Kuseler A, Pedersen TK, Herlin T. Intra-articular steroid injection for temporomandibular joint arthritis in juvenile idiopathic arthritis: a systematic review on efficacy and safety. Semin Arthritis Rheum 2013;43:63–70. 24. Powell CV, Kelly AM, Williams A. Determining the minimum clinically significant difference in visual analog pain score for children. Ann Emerg Med 2001;37:28–31. 25. Stoustrup P, Verna C, Kristensen KD, Kuseler A, Herlin T, Pedersen TK. Smallest detectable differences in clinical functional temporomandibular joint examination variables in juvenile idiopathic arthritis. Orthod Craniofac Res 2013;16:137–45. 26. Svensson P, Sessle BJ. Orofacial pain. In: Miles TS, Nauntofte B, Svensson P, editors. Clinical oral physiology.Copenhagen, Quintessence Publishing, 2004:93–139. 27. Mussler A, Allozy B, Landau H, Kallinich T, Trauzeddel R, Schroder RJ. [Comparison of magnetic resonance imaging signs and clinical findings in follow-up examinations in children and juveniles with temporomandibular joint involvement in juvenile idiopathic arthritis], in German. Rofo 2010;182:36–44. 28. Weiss PF, Arabshahi B, Johnson A, Bilaniuk LT, Zarnow D, Cahill AM, et al. High prevalence of temporomandibular joint arthritis at disease onset in children with juvenile idiopathic arthritis, as detected by magnetic resonance imaging but not by ultrasound. Arthritis Rheum 2008;58:1189–96. 29. McGrath PJ, Walco GA, Turk DC, Dworkin RH, Brown MT, Davidson K, et al. Core outcome domains and measures for pediatric acute and chronic/recurrent pain clinical trials: PedIMMPACT recommendations. J Pain 2008;9:771–83. 30. Stinson JN, Connelly M, Jibb LA, Schanberg LE, Walco G, Spiegel LR, et al. Developing a standardized approach to the assessment of pain in children and youth presenting to pediatric rheumatology providers: a Delphi survey and consensus conference process followed by feasibility testing. Pediatr Rheumatol Online J 2012;10:7.
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Management of temporomandibular joint arthritis-related orofacial symptoms in juvenile idiopathic arthritis by the use of a stabilization splint P Stoustrup1, KD Kristensen1, A Küseler1,3, C Verna1, T Herlin2, TK Pedersen1,3
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1 Section of Orthodontics, Aarhus University, 2Department of Paediatrics, Aarhus University Hospital, and 3Department of Maxillofacial Surgery, Aarhus University Hospital, Aarhus, Denmark
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.
Temporomandibular joint (TMJ) inflammation and degenerative joint alterations in patients with juvenile idiopathic arthritis (JIA) may interfere with optimal joint and muscular function and lead to mandibular growth disturbances (1–5). The presence of orofacial symptoms and functional impairments of the TMJ and the surrounding soft tissue are seen in 26–74% of JIA patients with TMJ arthritis, and disease duration correlates with craniofacial symptoms and dysfunction (3, 6). The main complaints associated with TMJ arthritis are reduced maximal opening capacity and transient pain during maximal mouth opening and mastication, in addition to TMJ morning stiffness (3, 4, 6–8). The symptoms most often involve both the TMJ and the masseter muscle areas; self-reported symptoms solely from the TMJ region are more rare (7). Therefore, TMJ arthritis must be recognized as involving more than the TMJ itself. Management is important because TMJ arthritis-induced orofacial symptoms may be disabling and interfere with daily life activities (3, 6, 9) and because optimal TMJ and muscular function are crucial to normal craniofacial development in children and adolescents (10).
Peter Stoustrup, Section of Orthodontics, Aarhus University, Vennelyst Boulevard 9-11, 8000 Aarhus, Denmark. E-mail: [email protected]
TMJ arthritis is a subdiagnosis of the more general umbrella term temporomandibular disorders (TMDs), and TMJ arthritis symptoms are comparable to those of other conditions covered by the general term (11, 12). The flat, acrylic stabilization splint has been important in the management of TMDs and orofacial symptoms for decades (13, 14), even though its mode of action while positioned on the teeth in the upper or lower jaw remains incompletely understood. Suggested mechanisms include repositioning of the condylar head in the TMJ, preventing high pressure on the joint surfaces, transient decrease in masticatory muscle activity, reduced bruxism, balanced occlusion, awareness of the cognitive-behavioral aspect of orofacial pain, and a placebo effect (15, 16). The stabilization splint in TMD treatment is controversial, with insufficient evidence for or against its use when compared to other active treatment modalities. However, some data suggest that stabilization splint therapy can alleviate TMD-related orofacial pain in adults and adolescents when compared to no active intervention (13–16). The effect of this therapy has not previously been evaluated in patients with JIA and TMJ arthritis-related orofacial symptoms. Because these symptoms are comparable to those of other TMDs described in the literature as possibly amenable to splint therapy, we hypothesized that stabilization splint therapy could alleviate TMJ
Accepted 25 July 2013 © 2014 Informa Healthcare on license from Scandinavian Rheumatology Research Foundation DOI: 10.3109/03009742.2013.830146
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arthritis-related orofacial pain and improve orofacial function despite not targeting inflammation. The present prospective observational study involved a consecutive cohort of patients with JIA and TMJ arthritisrelated orofacial symptoms undergoing stabilization splint therapy. The aims were to evaluate changes in sensory-discriminative components of self-reported orofacial symptoms (pain frequency, intensity, and localization, and main complaints) and changes in orofacial function when compared to a control group of age- and sex-matched healthy individuals.
Method Scand J Rheumatol Downloaded from informahealthcare.com by Nyu Medical Center on 04/24/15 For personal use only.
Participants A group of 33 consecutive patients with JIA and TMJ arthritis-related orofacial symptoms were identified as candidates for study inclusion (Table 1). All patients received examination and treatment of their TMJ conditions at the Section of Orthodontics, Aarhus University, Denmark, between September 2010 and July 2012. The initial TMJ arthritis diagnosis was based on a general assessment of the radiological findings obtained by cone beam computed tomography (CBCT) radiological evaluation in
Table 1. Cohort characteristics. TMJ arthritis group Control group (n ¼ 28) (n ¼ 110) Females, n (%) Mean age, years (range) TMJ involvement, individuals Unilateral Bilateral JIA diagnosis, individuals Oligoarticular extended Oligoarticular persistent Polyarticular RF negative Polyarticular RF positive Systemic Psoriatic Enthesitis related Unclassified Medication NSAID Methotrexate IACI * Systemic steroid Biologics No medication Combination of two drugs Combination of three drugs Combination of four drugs
26 (93) 15.5 (8.2–25)
100 (91) 14.9 (8.4–18)
12 16
– –
6 6 4 4 1 2 1 4
– – – – – –
10 13 2 0 10 6 8 1 1
– – – – – – – – –
TMJ, Temporomandibular joint; JIA, juvenile idiopathic arthritis; RF, rheumatoid factor; NSAID, non-steroidal anti-inflammatory drug; IACI, intra-articular corticosteroid. * Intra-articular TMJ steroid injection within the past year (not within the 4 months prior to inclusion in this study).
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combination with clinical findings obtained from our standardized orthodontic clinical examination protocol, described previously (7, 17). Radiological pathological findings were defined as conditions deviating from the normal TMJ outline on two-dimensional CBCT cuts (e.g. flattening, erosive changes, sclerosis, and osteophytes). The initial TMJ arthritis diagnosis was made based on a clinical impression; however, the diagnosis was independent of the presence of radiological pathological findings and/or orofacial symptoms. However, in this study, the presence of orofacial symptoms was a specific inclusion criterion. No contrast-enhanced magnetic resonance imaging (MRI) procedures were used for diagnosis of TMJ arthritis in the patients in this study because TMJ arthritisrelated orofacial pain, and not inflammation, was the target of the intervention.
Inclusion and exclusion criteria Inclusion and exclusion criteria were defined prior to study initiation. Inclusion criteria were: (i) JIA diagnosis according to the criteria of the International League of Associations for Rheumatology (18); (ii) the presence of TMJ arthritis-related orofacial symptoms based on our regular standardized clinical examination and radiological evaluation; and (iii) age 8 years and cognitively capable of understanding the standardized questionnaire and the concept of the visual analogue scale (VAS). Exclusion criteria were: (i) failure to comply with the instruction given on the use of the splint; (ii) ongoing treatment with functional orthopaedic appliances; (iii) treatment with intra-articular TMJ steroid injection or change in systemic medication within 4 months prior to the study; (iv) TMJ hypermobility based on a general clinical assessment; and (v) failure to attend the follow-up outcome evaluation less than 180 days after splint therapy initiation. The stabilization splint therapy complies with the rules of the Danish Board of Health for clinical paediatric dental treatment. The Danish Data Protection Agency approved handling of the confidential data, and the Danish Ministry of Health approved the use of the patient files.
Control group A control group of 110 individuals comparable for age and sex was included in the study to enable a comparison in function between patients with TMJ arthritis-related orofacial pain and healthy individuals. Data concerning mandibular function were obtained from the patient files of 110 healthy age- and sex-matched individuals from the public dental clinics in the council of Syddjurs, Denmark. These functional variables were assessed using a standardized measurement protocol identical to the one used in this study. None of the patients in the control group received splint treatment or were diagnosed with any orofacial symptoms.
Splint against orofacial pain
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Stabilization splint fabrication The stabilization splint used in this study was fabricated from impressions of the upper and lower dental arches and a recording of the centric position. From a clinical assessment, the centric position was defined as the optimal position of the mandible relative to the skull where the masticatory muscles are in their most relaxed and least strained position. A stabilization splint was fabricated and positioned in the mandible on the mandibular dentition. The splint was fabricated as a ‘flat’ splint with no impressions for occluding guidance. Occlusal and articular adjustments were made to the splint after fabrication to obtain a stable occlusal relationship with uniform contacts between the splint and the maxillary teeth throughout the range of the splint (Figure 1). Patients were instructed to use the splint during sleeping hours, at a minimum; further use was recommended in some patients based on individual clinical assessment. The use of the splint was individualized and based on the nature of their pain complaints. Additionally, participants received brief information about TMJ pathology and instruction in the correct use of the stabilization splint. Splint treatment was planned to continue until noticeable reduction or resolution of the orofacial pain was seen; at this point the use of the splint was gradually reduced based on individual recommendations. Patients were also advised to save the splint and use it for potential future episodes of TMJ arthritis-related pain. The start time of splint therapy was defined as T1. A follow-up visit was arranged 8 weeks after splint therapy began, referred to as T2.
Pain variables At T1 and T2, all patients completed a standardized questionnaire concerning orofacial pain assessment within the past 7 days, covering orofacial pain frequency, average pain intensity, pain-eliciting factors (‘In which situations do you feel the pain?’), and localization of pain on a schematic drawing illustrating the head and the neck. Pain frequency. Patients were asked to report the frequency of their orofacial symptoms on a five-point Likert scale: (i) pain less than once a week; (ii) pain 1–3 times a week; (iii) pain 4–6 times a week; (iv) pain several times a day; and (v) pain all the time.
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Pain intensity. The patients were asked to assess the average pain intensity on a non-verbal VAS of 100 mm, where the left extreme represents ‘no pain’ and the right extreme represents the ‘worst imaginable pain’. Pain index. To combine the aspects of orofacial frequency and intensity, this composite variable was created, calculated as the pain frequency multiplied by the pain intensity, with a score range between 0 and 500.
Clinical examination of functional variables At T1 and T2, all patients underwent a clinical examination. A standardized measurement protocol was used for the assessment of the maximal mouth opening capacity and laterotrusion capacity. The laterotrusion capacity was defined as the total amount of mandibular excursion from the leftmost side to the rightmost side (the sum of the right and the left laterotrusion movement capacities). All patients were carefully instructed in the correct performance of the specific manoeuvres before the measurements were made. Maximal mouth opening capacity and maximal laterotrusion capacity were measured with a calibrated regular 150mm metallic ruler. The patients were instructed to execute the maximal laterotrusion with a consistent contact between teeth in the upper and lower jaws. The horizontal overjet, vertical overbite, and any midline deviation were assessed before the measurements and accounted for in the measurement result. Additionally, pain on palpation of the masticatory muscles and the TMJs was recorded together with the assessment of clinical signs of internal derangement (e.g. crepitus, anterior discus displacement with or without reduction).
Statistics Pre- and post-treatment functional outcome variables were compared to the values in a control group of ageand sex-matched healthy individuals. Intra-group differences in pain variables and functional variables between T1 and T2 were assessed by paired Student’s t-tests after the data were tested for normal distribution. Changes in the categorical data concerning pain frequency were analysed statistically using a Wilcoxon matched-paired rank test for the evaluation of intra-group differences between
Figure 1. Frontal and occlusal view of a stabilization splint positioned in the lower jaw. The splint presented here is without incisal acrylic coverage.
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T1 and T2. The values of the functional variables at T1 and T2 were compared to the values of the age-matched healthy individuals by the use of student’s independent t-tests. Fisher’s two-tailed exact test was used to assess the changes in pain on palpation and clinical findings between T1 and T2. A p-value < 0.05 was considered significant. Correlation between maximal mouth opening capacity and the pain index was assessed by calculation of Pearson’s correlation coefficient.
Results
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Patients and control group Of the 33 identified candidates, 28 patients complied with the inclusion criteria (mean age 15.5 years; range 8.2–25 years; girls n ¼ 26; boys n ¼ 2). The five patients who did not comply with the inclusion criteria were excluded from the study for the following reasons: failure to comply with the instruction given on the use of the splint (n ¼ 2), a T2 follow-up evaluation more than 180 days after the splint therapy was initiated (n ¼ 2), and a change in general medication between T1 and T2 (n ¼ 1). Of the 28 included patients, arthritis-related orofacial symptoms were seen in relation to 44 TMJs. The majority of patients were diagnosed with either oligoarticular or polyarticular JIA subtypes. Further cohort characteristics are described in Table 1. The mean follow-up time between T1 and T2 was 56 days (SD ¼ 34.2). The functional outcome variables of the included patients were compared to 110 age- and sexmatched healthy controls with a mean age of 14.9 years (range 8.4–18 years, 100 girls and 10 boys).
statistically significantly reduced to a pain frequency score of 2.5 (median 2), a VAS pain intensity of 40.5 mm, and a pain index of 106. Further information is listed in Table 2 and intra-individual changes are illustrated in Figure 2A–D. At T2, four patients reported a substantial increase in their pain index scores, and four reported a minor increase in pain index scores between T1 and T2 (Figure 2C); the rest of the cohort (n ¼ 20) experienced minor to substantial reduction in pain index scores during this period (Figure 2D). The three patients with the highest T1 pain index scores all reported a significant reduction in this outcome variable at the follow-up evaluation (Figure 2C). The relative changes in pain index scores revealed that 15 of the group of 28 patients reported at least a 50% reduction in this primary pain outcome variable between T1 and T2 (Figure 2D). At T1, the majority of patients experienced selfreported orofacial symptoms: TMJ symptoms in 75% and 57% (right and left sides, respectively) and masseter muscle symptoms in 50% and 54% (right and left sides, respectively) during mastication (n ¼ 14) and maximal mouth opening procedures (n ¼ 6), in addition to TMJ morning stiffness (n ¼ 5) (Figure 3). At T2, a reduction in the number of patients experiencing symptoms from the TMJ (60% and 54%, right and left sides, respectively) and masseter muscle (35% and 39%, right and left sides, respectively) was seen (Figure 3). No change in the number of patients reporting symptoms during mastication (n ¼ 13), maximal mouth opening (n ¼ 7), TMJ loading (n ¼ 4), or morning stiffness (n ¼ 5) was seen between T1 and T2. However, in contrast to T1, no patient reported ‘pain all day long’ at T2. Figure 3 illustrates the total number of complaints at T1 and T2.
Pain variables and main complaints Before initiating the splint treatment (T1), the included patients reported the following values for pain: a pain frequency mean score of 3.1 (median score 3 equivalent to pain 4–6 times a week), a VAS pain mean intensity of 55.2 mm, and a pain index mean score of 178.6 (Table 2). At the T2 follow-up examination, all of these variables were
Clinical examination Figure 4 presents the results of the clinical examination at T1 and T2. A tendency towards a statistically significant reduction in the number of patients without pain on palpation and clinical findings at T2 (p ¼ 0.051) was observed; however, no statistical significant changes were observed in any of the categories between T1 and
Table 2. Pain and functional measures in JIA patients with TMJ arthritis receiving stabilization splint therapy.
Pain Pain frequency* Pain intensity (mm) Pain index Function Mouth opening (mm) Laterotrusion (mm)
Before treatment (T1)
After treatment (T2)
Difference (SD)
95% CI
p value
3.1 55.2 178.6
2.5 40.5 106.9
NA –14.8 (17.6) –71.7 (109.2)
NA –21.6 to –7.9 –11.4 to –29.4
0.0423 0.0001 0.0017
41.4 14.8
45.3 16.6
3.9 (5.2) 1.8 (3.8)
1.9–5.9 0.3–3.3
0.0005 0.0234
JIA, Juvenile idiopathic arthritis; TMJ, temporomandibular joint; SD, standard deviation; CI, confidence interval; NA, not applicable * Categorical data where patients have graded the frequency of orofacial pain from 1 to 5 and the mean scores at T1 and T2 are shown.
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Splint against orofacial pain
A 100
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Pain intensity p < 0.05
Pain frequency p < 0.05
B All the time
VAS score (mm)
80 Several times daily 60 4-6 times weekly 40 1-3 times weekly 20 < Week Pre treatment T1
Post treatment T2
Pre treatment T1
Pain Index p < 0.05
C
D
500
Post treatment T2
Relative change in Pain-index score T1 to T2
Relative change from T1 to T2/%
100
400 Pain Index
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0
300 200 100 0 Pre treatment T1
Post treatment T2
75 50 25 0 –25 –50 –75 –100
Figure 2. Outcome measures of pain. Horizontal dotted lines illustrate the 95% confidence intervals, and descending dotted line illustrates the mean decrease in pain intensity between T1 and T2. (A) Pain intensity on a visual analogue scale (VAS). (B) Pain frequency. (C) Pain index; composite pain variable combining the aspects of pain intensity and pain frequency (intensity frequency). (D) Relative reduction in pain index score between T1 and T2. The ‘zero’ on the y axis indicates ‘no relative change’. Note that more than half of the group receiving stabilization splint treatment experienced a reduction of more than 50%.
T2. Pain on palpation of both the TMJ and the masticatory muscles was the most frequent finding at T1 (n ¼ 10). In addition to TMJ and masticatory muscle pain on palpation, seven patients were diagnosed with at least one additional TMJ clinical finding: click (n ¼ 7), obviously reduced TMJ translation (n ¼ 4), anterior disc displacement without reduction and locking (n ¼ 1), and crepitation (n ¼ 3). At T1, pain on palpation either solely from the TMJ (n ¼ 2) or the masticatory muscles (n ¼ 1) was rare. At T2, seven patients (25%) had no pain on palpation or clinical findings, compared to one patient at T1 (4%). The number of patients with pain solely from the masticatory muscles increased from one to four patients between T1 and T2; however, this could be explained by the fact that six out of the 10 patients with ‘TMJ and muscle pain’ on palpation at T1 changed groups. At T2, three of these patients switched to the group with only masticatory muscle pain, and three had no pain on palpation or other clinical findings (Figure 4).
Functional variables Table 2 presents the changes in mean values of maximal mouth opening capacity and laterotrusion capacity between T1 and T2. Both maximal mouth opening capacity and maximal laterotrusion capacity significantly improved between T1 and T2. The mean follow-up changes were maximal mouth opening capacity of 3.9 5.2 mm and laterotrusion capacity of 1.8 3.8 mm. Table 3 presents the functional variables when compared to healthy and age-matched controls. Despite significant positive changes in TMJ function between T1 and T2 among treated patients, the TMJ function remained significantly reduced when compared to age- and sexmatched controls.
Correlation between function and pain At T1, no correlation between maximal mouth opening capacity and pain index score was observed (r ¼ –0.14).
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P Stoustrup et al Figure 3. (A) Main complaints before (T1) and after (T2) stabilization splint treatment. Grey bars illustrate T1 complaints, and black bars T2 complaints. The term ‘loading of the joint’ represents situations in which external load has been applied to the joint (e.g. when the head is placed on a pillow). (B) Face maps illustrating the relative localization of orofacial symptoms before (T1) and after (T2) treatment. The areas of the temporal muscle, the temporomandibular joint (TMJ), and the masseter muscle have been labelled.
Self-reported Orofacial Pain
A
T1 T2
TMJ morning stiffness Mastication Loading of the joint Max. mouth opening All day long When I am tired Headache Talking No pain No reported symptoms
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0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Number of patients T1 right
B
T1 left
11%
Temporalis area Temporomandibular joint
0%
11%
75%
57%
Masseter area
50%
54% 0%
0%
14%
0%
0%
4%
4%
11%
60%
0%
0%
0%
35%
39%
0%
0%
T2 left
T2 right
case of TMJ arthritis and TMDs in general, these goals have proved elusive. The main findings of this study are that, after splint therapy for TMJ arthritis-related orofacial symptoms in patients with JIA, a significant symptomatic relief was reported in terms of reduced orofacial pain frequency and intensity without substantially changing the pain locations or the nature of the self-reported complaints. Total resolution of orofacial pain was rare and the majority of patients had sustained self-reported
There also was no correlation between increased maximal mouth opening capacity and improvement in pain index score between T1 and T2 (r ¼ –0.023). Discussion The principal treatment goals for patients with TMJ arthritis are to achieve resolution of pain if present and normalize TMJ function and growth. However, in the
Pain on palpation and clinical findings T1 (F = 1.00) T2 (F = 0.25)
only TMJ pain only maslcalory muscle pain
(F = 1.00)
only clinical findings*
(F = 0.12)
TMJ and muscle pain (F = 1.00)
TMJ and muscle pain and clinical findings (F = 1.00)
Muscle pain and clinical findings TMJ pain and clinical findings
(F = 1.00) (F = 0.051)
None 0
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1 2 3 4 5 6 7 8 Number of patients
9 10 11
Figure 4. Pain on palpation and clinical findings. Grey bars illustrate T1 complaints, and black bars T2 complaints. Clinical findings represent, for example, temporomandibular joint (TMJ) click, obviously reduced TMJ translation, anterior discus displacement without reduction, locking, or crepitation. p-values are from Fisher’s exact test, twotailed.
Splint against orofacial pain
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Table 3. Functional outcome measures in JIA patients with TMJ arthritis receiving stabilization splint therapy in comparison to age- and sex-matched controls.
Before treatment (T1) Mouth opening (mm) Translation (mm) After treatment (T2) Mouth opening (mm) Laterotrusion (mm)
JIA group
HC
Difference (SD)
95% CI
p value
41.4 14.8
52 19.4
10.6 (10.9) 4.5 (6.2)
6.4–14.9 2.2–6.9
> 0.0000 0.0006
45.3 16.6
52 19.4
6.7 (10.1) 2.8 (4.7)
2.8–10.6 1–4.6
0.0015 0.0040
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JIA, Juvenile idiopathic arthritis; TMJ, temporomandibular joint; HC, healthy controls; SD, standard deviation; CI, confidence interval.
complaints and clinical findings at T2; however, more than half of the patients in the study group experienced at least a 50% reduction in pain index scores, pointing to a beneficial reduction in intensity and/or frequency. In this context it is important to note that the changes in pain scores revealed a sustained amount of actual pain after splint treatment had been conducted, indicating a large variation in the inter-patient response to this treatment. Based on our findings, it is our general impression that orofacial symptoms fluctuate over time and that the stabilization splint has a palliative (not curative) effect on the orofacial symptoms. In addition, even though patients had significant improvement in TMJ function at follow-up, this was still significantly reduced compared to that of healthy age- and sex-matched controls. We observed no correlation between the maximal mouth opening capacity and the level of orofacial symptoms, indicating that high pain scores are not directly reflected in reduced TMJ function in these patients. Previous research in this area has focused on a pharmacological approach using intra-articular TMJ steroid injections for MRI-verified inflammation (19–23). The splint therapy described here involves a functional physiotherapeutic management strategy against TMJ arthritis-related orofacial symptoms independent of TMJ inflammation status. A direct comparison between previous and current findings would be interesting but potentially misleading because of differences in management strategy (physical vs. pharmacological), baseline cohort characteristics, and treatment indications. It is noteworthy, however, that the functional improvements identified here are comparable to, and even exceed, the level of functional improvement described in studies reporting the effect of intra-articular TMJ steroid intervention (19, 21–23). The pain localizations and main complaints identified in the current work are comparable to previous descriptive studies on TMJ arthritis symptoms in patients with JIA (3, 6, 7). The orofacial pain may not be caused directly by the arthritic condition but rather as a secondary phenomenon caused by chronic joint alterations that follow the TMJ arthritis. In this context it is therefore important to emphasize that stabilization splint therapy is not a treatment against TMJ inflammation but a treatment aimed at the related orofacial pain issues that are seen in some patients with JIA and TMJ arthritis.
Because of the fluctuation of TMJ arthritis-related symptoms in patients with JIA and the limited number of patients in this study, it is difficult to draw general conclusions based on our clinical findings; however, we can hypothesize that stabilization splint therapy may reduce the intensity and frequency of TMJ arthritis-related symptoms without changing the number of other complaints (TMJ morning stiffness, pain on mastication, loading of the joint, pain on maximal mouth opening) in the group of treated patients. We note that more than half of the patients reported a 50% reduction in pain at post-treatment followup and that a quarter of the patients experienced no pain on palpation or other clinical findings at T2. Previous studies dealing with TMJ arthritis interventions in patients with JIA did not quantify pain, using VAS for example, and comparisons between our related findings and studies on pain management in this patient population are not possible. However, the mean 15-mm improvement we identified in VAS score for pain intensity at follow-up exceeded both the smallest detectable difference within this assessment technique and values for minimal clinically relevant differences in self-reported pain assessment in children (7, 24). By contrast, the functional improvements we identified did not exceed the smallest detectable difference (i.e. the variation within the measurement technique) despite significant differences in maximal mouth opening capacity and laterotrusion capacity between T1 and T2 (25). This result agrees with previous findings in patients receiving pharmacological intervention against TMJ arthritis-related symptoms, in which improvements in mandibular function were not large enough to exceed the smallest detectable difference within the measurement technique (23, 25). The splint therapy has a different aim of action than intraarticular TMJ steroid intervention. The physiological and placebo effects of the stabilization splint are unknown but are unlikely to be anti-inflammatory (14, 15, 26). In terms of TMJ arthritis, only a limited association exists between clinical signs and symptoms and MRI-verified signs of TMJ inflammation in patients with JIA (19, 27, 28). We have therefore previously suggested a dual approach to TMJ arthritis-related orofacial symptoms that combines antiinflammatory therapies with other pain management strategies such as a stabilization splint treatment (7).
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Stabilization splint intervention is reversible, conservative, safe, familiar, and low cost, with manufacture requiring only limited specialized dental education, and many general dental practitioners are familiar with this treatment modality (13, 14). This therapy is the primary intervention in our department when patients are diagnosed with TMJ arthritis-related orofacial symptoms. An advantage is that it can serve as a singletreatment modality or can be used in combination with other management strategies such as intra-articular TMJ steroid injection, physiotherapy, and/or systemic antiinflammatory intervention. Our study had some limitations. Neither patients nor assessors were blinded to treatment or outcome variables, the patient numbers were limited, and we had no placebo group with TMJ arthritis-related symptoms because of the observational design. Without a placebo group, we cannot show a cause–effect relationship between the use of the stabilization splint and the symptomatic relief and functional improvements identified. Therefore, we cannot exclude the possibility that increased awareness focusing on the orofacial symptoms of the patients could have elicited a placebo effect in combination with the natural fluctuating course of the orofacial symptoms and contributed to the improvements (26). However, despite the lack of a placebo group, our preliminary findings suggest a beneficial effect of the splint therapy. A potential source of bias was the design chosen for the study; because we wanted to assess the efficacy of the stabilization splint in patients who were compliant to the predefined treatment protocol, we applied a ‘per-protocol’ design and not an ‘intention-to-treat’ design. We acknowledge the possibility that excluding the patients violating the treatment protocol from the final analysis could maximize the described effect. This is because treatment compliance may be compromised if the initial pain reduction effect is not in agreement with the self-perceived ‘burden’ of the treatment. Future studies in accordance with evidence-based standards including a placebo-treated group of patients and with ‘intention-to-treat’ analysis designs are needed to evaluate the true cause-and-effect relationship of splint therapy in patients with JIA and TMJ arthritis. The study’s strengths include its standardized and specific treatment protocol, prespecified outcome variable evaluation protocol, and the inclusion of an age- and sex-matched control group. Additionally, in contrast to previous literature on TMJ arthritis management in patients with JIA, the current work involved a more comprehensive evaluation of various aspects of orofacial symptoms (e.g. intensity, frequency, localization, and main complaints) in accordance with contemporary clinical consensus guidelines on pain assessment in paediatric patients (29, 30). However, not all of these clinical variables (e.g. pain index) have yet been validated in this group of patients, which is a potential weakness in the standardized examination carried out.
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P Stoustrup et al
Conclusions The current results provide evidence to support the hypothesis that stabilization splint therapy may reduce the intensity and frequency of TMJ arthritis-related symptoms and improve mandibular function. The stabilization splint involves a different management aspect from previous studies dealing with pharmacological approaches to TMJ arthritis-related orofacial symptoms and is reversible, conservative, safe, familiar to most dentists, and low cost. Based on our findings, we propose the implementation of stabilization splint therapy in the treatment of JIA patients with TMJ arthritis-related symptoms. Acknowledgements We thank the entire staff of the rheumatic team at the Section of Orthodontics, Aarhus University, Denmark, and the employees of Syddjurs Council Dental Service for their collaboration in this project. We also thank graphic designer Nikolai Lander for assistance with the illustrations.
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