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Randomized clinical trial of primary treatment for temporomandibular joint disk displacement without reduction and without osseous changes: A combination of NSAIDs and mouth-opening exercise versus no treatment
Randomized clinical trial of primary treatment for temporomandibular joint disk displacement without reduction and without osseous changes: A combination of NSAIDs and mouth-opening exercise versus no treatment Hidemichi Yuasa, DDS, PhD, Kenichi Kurita, DDS, PhD, and The Treatment Group on Temporomandibular Disorders,* Nagoya, Japan AICHI-GAKUIN UNIVERSITY
Objective. The effectiveness of nonsteroidal anti-inflammatory drugs (NSAIDs) and physical therapy for disk displacement without reduction is unknown. This study compared this treatment method with nontreatment controls.
Methods. Sixty patients with painful disk displacement without reduction and without osseous changes were randomly divided in 2 groups, consisting of NSAID and physical therapy and a nontreated control group. Both groups were observed at 2 weeks and, for those patients who did not show any improvement, again at 4 weeks. Results. There was 60% improvement in the treatment group compared with 33% in the control group during the entire 4 weeks of the study. The number needed to treat for benefit was 3.75, with a 95% CI 2.103 to 65.935. Conclusions. A combination of NSAID and physical therapy for 4 weeks is effective as a primary treatment of patients with disk displacement without reduction and without osseous changes.
(Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2001;91:671-5)
A multitude of treatment modalities have been applied to patients with temporomandibular disorders (TMD)1,2 but very few studies have systematically evaluated the effect of these treatments.3-6 In our preliminary study, we applied 5 treatment methods to a group of patients: (1) oral administration of nonsteroidal anti-inflammatory drugs (NSAIDs), (2) NSAIDs and physical therapy,7,8 (3) arthrocentesis,9 (4) arthrocentesis and single injection of steroid,10 and (5) occlusal splint. As a result, we found that the combination of NSAIDs and physical therapy was the most effective treatment.11 This earlier study was a randomized study without a control group, and the population was too small for statistical analysis. Thus, in the current randomized clinical study, we used the most effective treatment method from our preliminary study and compared it with a nontreated control group of patients with anterior disk *The Treatment Group on Temporomandibular Disorders from the School of Dentistry at Aichi-Gakuin University includes: Hidemichi Yuasa, DDS, PhD, Nobumi Ogi, DDS, PhD, Masahiko Toyama, DDS, PhD, Izumi Maki, DDS, Echiverre Neil, DDS, and Isamu Katoh, DDS, The Second Department of Oral and Maxillofacial Surgery; Kenichi Kurita, DDS, PhD, The First Department of Oral and Maxillofacial Surgery; Eiichiro Ariji, DDS, PhD, Department of Oral and Maxillofacial Radiology; Akizumi Araki, DDS, PhD, and Yutaka Ito, DDS, PhD, The Third Department of Prosthetic Dentistry. Received for publication Mar 21, 2000; returned for revision May 12, 2000; accepted for publication Dec 14, 2000. Copyright © 2001 by Mosby, Inc. 1079-2104/2001/$35.00 + 0 7/13/114005 doi:10.1067/moe.2001.114005
displacement without reduction and without osseous changes.
METHODS Subjects This study was conducted at our institution during a 15-month period. From a consecutive series of 662 new patients seen during this period with temporomandibular joint (TMJ) disk displacement, 60 patients were selected. We classified the degree of TMJ dysfunction in 4 categories—no dysfunction, slight dysfunction, moderate dysfunction, or severe dysfunction (Table I).12 This classification is a modification of the TMJ criteria established by the American Association of Oral and Maxillofacial Surgeons and the International Association of Oral and Maxillofacial Surgeons.13,14 The inclusion criteria were unilaterally moderate or severe TMJ dysfunction lasting 2 weeks or more and magnetic resonance imaging (MRI) showing disk displacement without reduction and without osseous changes. Patients who had pain other than in the TMJ region were excluded in this study. Therefore, patients with myofascial pain dysfunction were eliminated. Patients who had undergone other treatment for the 4 weeks immediately before enrollment in this study were excluded as were patients who were unable to take NSAIDs. Eighteen patients who were initially selected for the study refused to participate, and 1 patient was not included in the study because of a registration error. On the basis of these criteria, we enrolled 60 patients with moderate or severe TMJ 671
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Table I. Classification of TMJ dysfunction without use of radiographic evaluation
Table II. Baseline characteristics of patients in study
Degree of TMJ dysfunction None Slight Moderate Severe
Maximal mouth opening (mm)
Maximal value of visual analog scales* (0-100)
≥40 35-39 30-34 ≤29
0 1-33 34-66 67-100
Degree of disturbance calculated on the basis of least amount of mouth opening or maximal value on visual analog scales. *Visual analog scales measured pain at rest, pain with mandibular motion, pain on chewing, and interference with daily life.
dysfunction and we randomly divided the patients into a treatment group and nontreatment group. There were no dropouts or cases of adverse reaction to the medication during the entire period of the study. The patients’ ages ranged from 16 to 69 years, with a median age of 28 years. Eighty percent of the patients were female. There was no statistically significant difference regarding age, sex, or period of closed lock when the treatment and control groups were compared (Table II). Informed consent was obtained according to the Helsinki declaration. Our institution’s Committee for Human Research approved the study.
TMJ dysfunction classification and clinical evaluation The degree of TMJ dysfunction was determined by a measurement of maximum mouth opening and selfassessment with the 4 TMJ visual analog scales (pain at rest, pain with mandibular motion, pain on chewing, and interference with daily life [Table I]). The worst rating on any of these 4 scales and the limitation of mouth opening was used to classify the patient’s degree of TMJ dysfunction. If the maximum mouth opening and the visual analogue scales resulted in a different degree of TMJ dysfunction, the most severe rating was noted. The same classification was used at the initial and at the follow-up examinations. The patients remaining in the moderate or severe TMJ dysfunctional group at the follow-up were classified as no improvement. Those who had gone down to slight or no TMJ dysfunction were classified as improved. Imaging Bilateral MRI was obtained on a 1.0 tesla MR imager (SMF Shimadzu Corp, Tokyo, Japan) with bilateral 10 × 10-cm surface coils. Images were obtained in an oblique sagittal plane at the closed and opened mouth position. The degree of angulation of the imaging plane was determined on an axial scout image. Repetition time was 1000 ms, echo time was 20 ms, slice thick-
Demography Median (range) age in years No. of patients <31 y No. of patients ≥31 y Female Male Clinical characteristics Median (range) period of closed lock in days No. of patients ≤30 d No. of patients ≥31 d
Treatment group (n = 30)
Control group (n = 30)
25.5 (17-64)
28 (16-61)
17 (57%) 13 (43%) 22 (73%) 8 (27%)
18 (60%) 12 (40%) 26 (87%) 4 (13%)
70 (16-752)
98 (19-1254)
8 (27%) 22 (73%)
7 (23%) 23 (77%)
ness was 4 mm, and field-of-view was 20 cm. Two excitations were used. The scanning time was 4 minutes and 28 seconds, with a matrix of 256 × 256.
Patient management In the treatment group, an NSAID (Ampiroxicam, 27 mg) was given orally once a day after commencing the study. Subjects were instructed to perform a range of motion exercises 4 times per day (3 times after each meal and once before bedtime). In the mouth-opening exercise, the thumb was placed on the maxillary anterior teeth and the forefinger on the mandibular anterior teeth, creating a forceful opening. The maximal mouth opening was held for 10 seconds for 10 times. Also, lateral and anterior mandibular movements were repeated 10 times. A printed instruction manual was given to all the participants. All patients were followed up on the second week. If the TMJ dysfunction improved after 2 weeks, treatment was stopped for the treatment group according to the instruction of our ethical committee. All of the improved patients, whether they belonged to the treatment or the control group, were informed to visit our clinic if there was a relapse of TMJ symptoms. However, improved patients on the second week did not come back on the fourth week, so we presumed that their condition was stable. On the other hand, if the TMJ dysfunction did not improve by the second week, the patients in the treatment group were given further treatment. All the patients who did not show improvement were followed up on the fourth week. To determine the effect of this combination treatment within a 4-week period, the total improvement rate was based on the second and fourth weeks. Sample size and randomization Kurita et al15 have shown that 48% of the patients with disk displacement without reduction improved after a 6-
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Table III. Changes in TMJ dysfunction in treatment and control groups Treatment group (no. of patients) Initial registration
2nd week
2nd and 4th weeks*
— — 10 (33%) 20 (67%)
1 (3%) 10 (33%) 12 (40%) 7 (23%) 37%
2 (7%) 16 (53%) 6 (20%) 6 (20%) 60%†
None Slight Moderate Severe Improvement rate *Accumulated
Control group (no. of patients) Initial registration — — 9 (30%) 21 (70%)
2nd week
2nd and 4th weeks*
0 7 (23%) 9 (30%) 14 (47%) 23%
0 10 (33%) 8 (27%) 12 (40%) 33%†
results of second- and fourth-week examination. test, P = .019.
†Cochran-Mantel-Haenszel
Table IV. Changes in TMJ dysfunction: Individual median Treatment group
Maximal mouth opening (mm) Joint pain at rest (VAS) Joint pain on opening and closing (VAS) Joint pain on chewing (VAS) Interference with daily life (VAS)
Control group
Entry
2nd and 4th week
P value
Entry
2nd and 4th week
P value
29 0 51.5 53.5 46.5
37.5 0 28 25.5 22
.000 .711 .001 .001 .001
30 0 51.5 57 30
33.5 0 32 22 28.5
.029 .579 .004 .036 .290
P values calculated with Wilcoxon rank sum test. VAS, Visual analog scale.
Table V. Difference in values between entry and outcome of 4-week study Maximal mouth opening (mm) Joint pain at rest (VAS) Joint pain on opening and closing (VAS) Joint pain on chewing (VAS) Interference with daily life (VAS)
Treatment group
Control group
P value
7 0 –26 –20 –20
1.5 0 –13 –6 –1.5
.005 .823 .297 .162 .040
P values calculated with Mann-Whitney U test. Values shown as median. VAS, Visual analog scale.
month period without treatment. Therefore, the estimated rate of improvement for the control group during the first month would be 10% to 20%. The reported improvement rate for combining NSAIDs and motion exercises was 43.5% after a 3-month treatment.11 Therefore, it was assumed that the improvement rate of the treatment and control groups would be 15% and 50%, respectively, given a dropout rate of 10%. Thus, we estimated that 30 patients would be required per group when a 2-sided test was applied to the data (α = 0.05, β = 0.2). Patients were randomized to 1 of the 2 groups. The stratification was made on the basis of the patient’s age (16 to 30 years or 31 to 70 years), closed-lock period (0 to 30 days or more than 31 days), and classification of TMJ dysfunction (moderate or severe dysfunction) by random permuted blocks within strata.16
Statistical and subgroup analysis The improvement rate was calculated by dividing the number of improved cases over the total number of each group. The Cochran-Mantel-Haenszel test adjusted by age, closed-lock period, and TMJ dysfunc-
tion was used for comparing the improvement rates between the 2 groups. P values less than .05 were considered to indicate statistical significance. Subgroup analysis was performed by using the Wilcoxon rank sum test, the Mann-Whitney U test, or the Fisher exact test. Our data were analyzed by using SAS/STAT, version 6.12 (SAS Institute Inc, Cary, NC, 1997).
RESULTS According to the classification of TMJ dysfunction, there was no statistically significant difference between the 2 groups on the second week of follow-up. However, at the end of the 4-week period of the study, the treatment group improved by 60% compared with 33% in the control group (Table III, P < .019). The number needed to treat for benefit was 3.75, with 95% CI 2.103 to 65.935. When values were compared between the entry and the outcome of the 4-week study, significant improvement was found in maximal mouth opening, pain on opening and closing, and pain on chewing in both groups (Table IV). When the difference in values
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Table VI. Changes in TMJ dysfunction: Stratified initial degree
Table VII. Baseline characteristics and improvement rate
Initial degree of TMJ dysfunction Treatment group Moderate
No. of patients 10
Severe
20
Total
30
Control group Moderate
9
Severe
21
Total
30
2nd and 4th week
Improvement rate
Improved 4 Not improved 6 Improved 14 Not improved 6 Improved 18 Not improved 12
40% 60% 70% 30% 60% 40%
Improved 3 Not improved 6 Improved 7 Not improved 14 Improved 10 Not improved 20
33% 67% 33% 67% 33% 67%
between the entry and the outcome of the 4-week study were compared between treatment and control groups, maximal mouth opening and interference with daily life showed significant improvement in the treatment group (Table V). When analyzed according to the degree of TMJ dysfunction, the patients with severe dysfunction responded better to the treatment than the other patients (Table VI). With respect to age, patients older than 31 years responded better than those younger than 30 years (Table VII). When the results were interpreted according to the period of closed lock, patients with a longer period of closed lock improved more after treatment.
DISCUSSION This study proved that a combination of NSAIDs and physical therapy administered for 4 weeks was effective as a primary treatment for patients with disk displacement without reduction and absence of osseous changes. This treatment significantly reduced pain and interference with daily life and improved maximal mouth opening. In a randomized study, it is important to select patients with TMD on the basis of both clinical and MRI findings. According to our previous study,16 clinical examination alone misdiagnosed 27% of the patients. This is because of the absence of typical clinical manifestations of disk displacement without reduction. On the other hand, MRI alone could not show the degrees of TMJ dysfunction.16 Diagnoses of patients included in the study were verified by clinical and MRI findings. Therefore, patient selection for this study satisfied all the criteria needed. Both age and period of locking were influential
Age <30 y ≥31 y Period of closed lock ≤30 d ≥31 d *Fisher
Improvement rate in treatment group
Improvement rate in control group
P value*
59% 62%
44% 17%
.505 .041
75% 55%
71% 22%
1.0 .033
exact test.
factors of disk displacement without reduction in previous studies. Patients younger than 30 years could usually open their mouth wider than patients older than 30 years.16,17 It was also reported that closed lock within the period of 4 weeks was easily reduced by manipulation,18 and patients with a longer duration of locking were less responsive to conservative treatments.19 Therefore, patients in this study were randomly divided according to age and period of locking. This subgrouping was proved to be correct because our results showed 2 significant differences between the control and the treatment group. On the basis of age, patients older than 31 years responded to the treatment better than those younger than 30 years. On the basis of the period of locking, patients with longer period of closed lock responded better to the treatment. We expected that patients with moderate dysfunction should improve more than those with severe dysfunction in both treatment and control groups. However, the results were contrary to our expectation. A significant improvement was noted in the severe dysfunction treatment group. This indicates that combination of NSAIDs and physical therapy is especially effective on patients with severe TMJ dysfunction. It was difficult to decide on the duration of this randomized study. However, it was decided that a period of 4 weeks would be enough for the following reasons: the result of our previous study showed that the average improvement period by NSAIDs and physical therapy was 44.6 days,11 a prolonged administration of NSAIDs might cause adverse reaction, and it is difficult to recruit and follow-up patients without improvement for more than 4 weeks. The results also showed that combination therapy should be used for more than 2 weeks because no significant difference in the improvement rate between the 2 groups occurred until the fourth week. Being the primary referral center for patients with TMD in our institution, our patient population is
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comparable with other TMJ/TMD clinics.5 There were enough patients to satisfy the sample size needed. Sixty of the 79 eligible patients (76%) were recruited for the study. This high percentage means that the results of this study are reliable.
ment with flat occlusal splint versus no treatment. Oral Surg Oral Med Oral Pathol 1992;73:655-8. Kirk WS Jr, DK Calabrese. Clinical evaluation of physical therapy in the management of internal derangement of the temporomandibular joint. J Oral Maxillofac Surg 1989;47: 113-9. Bertolami CN, Gay T, Clark GT, Rendell J, Shetty V, Liu C, et al. Use of sodium hyaluronate in treating temporomandibular joint disorders: a randomized, double-blind, placebo-controlled clinical trial. J Oral Maxillofac Surg 1993;51:232-42. Dimitroulis G, Dolwick MF, Martinez A. Temporomandibular joint arthrocentesis and lavage for the treatment of closed lock: a follow-up study. Br J Oral Maxillofac Surg 1995;33:23-7. Nitzan DW, Dolwick MF, Martinez GA. Temporomandibular joint arthrocentesis: a simplified treatment for severe, limited mouth opening. J Oral Maxillofac Surg 1991;49:1163-7. Yuasa H, Kurita K, Ogi N, Maki I, Toyama M, Ito Y, et al. Comparison of primary treatments for TMJ closed lock without osteoarthritis: ITT analysis. J Jpn Soc TMJ 1997;9:343-55. Kurita K, Westesson PL, Yuasa H, Toyama M, Machida J, Ogi N. Natural course of untreated symptomatic temporomandibular joint disc displacement without reduction. J Dent Res 1998;77: 361-5. Ad hoc study group on TMJ meniscus study: 1984 criteria for TMJ meniscus surgery. American Association of Oral and Maxillofacial Surgeons; 1984 November 15-28; Chicago, Ill. Goss AN. Toward an international consensus on temporomandibular joint surgery. Int J Oral Maxillofac Surg 1993; 22:78-81. Kurita K, Westesson PL, Yuasa H, Toyama M, Ogi N, Narita Y, et al. Clinical findings of closed lock (2) natural history over a 6 or 12 month period. J Jpn Soc TMJ 1993;5:415-26. Yuasa H, Kurita K, Narita Y, Ogi N, Jinno Y, Kawai T, et al. Clinical findings of closed lock 1. Untreated unilateral closed lock on initial visit. J Jpn Soc TMJ 1991;3:345-52. Minagi S, Nozaki S, Sato T, Tsura H. A manipulation technique for treatment of anterior disk displacement without reduction. J Prosthet Dent 1991;65:686-91. Farrar WB. Characteristics of the condylar path in internal derangements of the TMJ. J Prosthet Dent 1978;39:319-44. Totsuka Y, Sawada A, Nakamura T. Clinical assessment for treatment of patients with closed-lock of the TMJ. Jpn J Oral Maxillofac Surg 1988;34:1325-37.
CONCLUSION The combination of NSAIDs and physical therapy administered for 4 weeks proved to be an effective primary treatment for disk displacement without reduction and without osseous changes. The results of this study are applicable to any patient group, because the sex ratio was similar to the incidence of TMD as previously reported. We thank Nobuyuki Hamajima, MD, MPH, of the Aichi Cancer Center Research Institute Laboratory of Epidemiology, and Per-Lennart Westesson, MD, DDS, PhD, of the Department of Radiology, University of Rochester School of Medicine and Dentistry, for their assistance.
7.
8.
9. 10. 11. 12.
13. 14.
REFERENCES 1. Dimitroulis G. Temporomandibular disorders: a clinical update. BMJ 1998;317:190-4. 2. Brazeau GA, Gremillion HA, Widmer CG, Mahan PE, Benson MB, Mauderli AP, et al. The role of pharmacy in the management of patients with temporomandibular disorders and orofacial pain. J Am Pharm Assoc (Wash) 1998;38:354-61; quiz 3623. 3. Linde C, Isacsson G, Jonsson BG. Outcome of 6-week treatment with transcutaneous electric nerve stimulation compared with splint on symptomatic temporomandibular joint disk displacement without reduction. Acta Odontol Scand 1995;53:92-8. 4. Gray RJ, Quayle AA, Hall CA, Schofield MA. Physiotherapy in the treatment of temporomandibular joint disorders: a comparative study of four treatment methods. Br Dent J 1994;176:25761. 5. Schiffman EL. The role of the randomized clinical trial in evaluating management strategies for temporomandibular disorders. In: Fricton JR, Dubner R, editors. Orofacial pain and temporomandibular disorders (advances in pain research and therapy, Vol 21). New York: Raven Press; 1995. p. 415-63. 6. Lundh H, Westesson PL, Eriksson L, Brooks SL. Temporomandibular joint disk displacement without reduction. Treat-
15. 16. 17. 18. 19.
Reprint requests: Hidemichi Yuasa, DDS, PhD The Second Department of Oral and Maxillofacial Surgery Aichi-Gakuin University Suemori-Dori, Chikusa-ku Nagoya 464-8651 Japan [email protected]
Objective. The effectiveness of nonsteroidal anti-inflammatory drugs (NSAIDs) and physical therapy for disk displacement without reduction is unknown. This study compared this treatment method with nontreatment controls.
Methods. Sixty patients with painful disk displacement without reduction and without osseous changes were randomly divided in 2 groups, consisting of NSAID and physical therapy and a nontreated control group. Both groups were observed at 2 weeks and, for those patients who did not show any improvement, again at 4 weeks. Results. There was 60% improvement in the treatment group compared with 33% in the control group during the entire 4 weeks of the study. The number needed to treat for benefit was 3.75, with a 95% CI 2.103 to 65.935. Conclusions. A combination of NSAID and physical therapy for 4 weeks is effective as a primary treatment of patients with disk displacement without reduction and without osseous changes.
(Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2001;91:671-5)
A multitude of treatment modalities have been applied to patients with temporomandibular disorders (TMD)1,2 but very few studies have systematically evaluated the effect of these treatments.3-6 In our preliminary study, we applied 5 treatment methods to a group of patients: (1) oral administration of nonsteroidal anti-inflammatory drugs (NSAIDs), (2) NSAIDs and physical therapy,7,8 (3) arthrocentesis,9 (4) arthrocentesis and single injection of steroid,10 and (5) occlusal splint. As a result, we found that the combination of NSAIDs and physical therapy was the most effective treatment.11 This earlier study was a randomized study without a control group, and the population was too small for statistical analysis. Thus, in the current randomized clinical study, we used the most effective treatment method from our preliminary study and compared it with a nontreated control group of patients with anterior disk *The Treatment Group on Temporomandibular Disorders from the School of Dentistry at Aichi-Gakuin University includes: Hidemichi Yuasa, DDS, PhD, Nobumi Ogi, DDS, PhD, Masahiko Toyama, DDS, PhD, Izumi Maki, DDS, Echiverre Neil, DDS, and Isamu Katoh, DDS, The Second Department of Oral and Maxillofacial Surgery; Kenichi Kurita, DDS, PhD, The First Department of Oral and Maxillofacial Surgery; Eiichiro Ariji, DDS, PhD, Department of Oral and Maxillofacial Radiology; Akizumi Araki, DDS, PhD, and Yutaka Ito, DDS, PhD, The Third Department of Prosthetic Dentistry. Received for publication Mar 21, 2000; returned for revision May 12, 2000; accepted for publication Dec 14, 2000. Copyright © 2001 by Mosby, Inc. 1079-2104/2001/$35.00 + 0 7/13/114005 doi:10.1067/moe.2001.114005
displacement without reduction and without osseous changes.
METHODS Subjects This study was conducted at our institution during a 15-month period. From a consecutive series of 662 new patients seen during this period with temporomandibular joint (TMJ) disk displacement, 60 patients were selected. We classified the degree of TMJ dysfunction in 4 categories—no dysfunction, slight dysfunction, moderate dysfunction, or severe dysfunction (Table I).12 This classification is a modification of the TMJ criteria established by the American Association of Oral and Maxillofacial Surgeons and the International Association of Oral and Maxillofacial Surgeons.13,14 The inclusion criteria were unilaterally moderate or severe TMJ dysfunction lasting 2 weeks or more and magnetic resonance imaging (MRI) showing disk displacement without reduction and without osseous changes. Patients who had pain other than in the TMJ region were excluded in this study. Therefore, patients with myofascial pain dysfunction were eliminated. Patients who had undergone other treatment for the 4 weeks immediately before enrollment in this study were excluded as were patients who were unable to take NSAIDs. Eighteen patients who were initially selected for the study refused to participate, and 1 patient was not included in the study because of a registration error. On the basis of these criteria, we enrolled 60 patients with moderate or severe TMJ 671
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Table I. Classification of TMJ dysfunction without use of radiographic evaluation
Table II. Baseline characteristics of patients in study
Degree of TMJ dysfunction None Slight Moderate Severe
Maximal mouth opening (mm)
Maximal value of visual analog scales* (0-100)
≥40 35-39 30-34 ≤29
0 1-33 34-66 67-100
Degree of disturbance calculated on the basis of least amount of mouth opening or maximal value on visual analog scales. *Visual analog scales measured pain at rest, pain with mandibular motion, pain on chewing, and interference with daily life.
dysfunction and we randomly divided the patients into a treatment group and nontreatment group. There were no dropouts or cases of adverse reaction to the medication during the entire period of the study. The patients’ ages ranged from 16 to 69 years, with a median age of 28 years. Eighty percent of the patients were female. There was no statistically significant difference regarding age, sex, or period of closed lock when the treatment and control groups were compared (Table II). Informed consent was obtained according to the Helsinki declaration. Our institution’s Committee for Human Research approved the study.
TMJ dysfunction classification and clinical evaluation The degree of TMJ dysfunction was determined by a measurement of maximum mouth opening and selfassessment with the 4 TMJ visual analog scales (pain at rest, pain with mandibular motion, pain on chewing, and interference with daily life [Table I]). The worst rating on any of these 4 scales and the limitation of mouth opening was used to classify the patient’s degree of TMJ dysfunction. If the maximum mouth opening and the visual analogue scales resulted in a different degree of TMJ dysfunction, the most severe rating was noted. The same classification was used at the initial and at the follow-up examinations. The patients remaining in the moderate or severe TMJ dysfunctional group at the follow-up were classified as no improvement. Those who had gone down to slight or no TMJ dysfunction were classified as improved. Imaging Bilateral MRI was obtained on a 1.0 tesla MR imager (SMF Shimadzu Corp, Tokyo, Japan) with bilateral 10 × 10-cm surface coils. Images were obtained in an oblique sagittal plane at the closed and opened mouth position. The degree of angulation of the imaging plane was determined on an axial scout image. Repetition time was 1000 ms, echo time was 20 ms, slice thick-
Demography Median (range) age in years No. of patients <31 y No. of patients ≥31 y Female Male Clinical characteristics Median (range) period of closed lock in days No. of patients ≤30 d No. of patients ≥31 d
Treatment group (n = 30)
Control group (n = 30)
25.5 (17-64)
28 (16-61)
17 (57%) 13 (43%) 22 (73%) 8 (27%)
18 (60%) 12 (40%) 26 (87%) 4 (13%)
70 (16-752)
98 (19-1254)
8 (27%) 22 (73%)
7 (23%) 23 (77%)
ness was 4 mm, and field-of-view was 20 cm. Two excitations were used. The scanning time was 4 minutes and 28 seconds, with a matrix of 256 × 256.
Patient management In the treatment group, an NSAID (Ampiroxicam, 27 mg) was given orally once a day after commencing the study. Subjects were instructed to perform a range of motion exercises 4 times per day (3 times after each meal and once before bedtime). In the mouth-opening exercise, the thumb was placed on the maxillary anterior teeth and the forefinger on the mandibular anterior teeth, creating a forceful opening. The maximal mouth opening was held for 10 seconds for 10 times. Also, lateral and anterior mandibular movements were repeated 10 times. A printed instruction manual was given to all the participants. All patients were followed up on the second week. If the TMJ dysfunction improved after 2 weeks, treatment was stopped for the treatment group according to the instruction of our ethical committee. All of the improved patients, whether they belonged to the treatment or the control group, were informed to visit our clinic if there was a relapse of TMJ symptoms. However, improved patients on the second week did not come back on the fourth week, so we presumed that their condition was stable. On the other hand, if the TMJ dysfunction did not improve by the second week, the patients in the treatment group were given further treatment. All the patients who did not show improvement were followed up on the fourth week. To determine the effect of this combination treatment within a 4-week period, the total improvement rate was based on the second and fourth weeks. Sample size and randomization Kurita et al15 have shown that 48% of the patients with disk displacement without reduction improved after a 6-
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Table III. Changes in TMJ dysfunction in treatment and control groups Treatment group (no. of patients) Initial registration
2nd week
2nd and 4th weeks*
— — 10 (33%) 20 (67%)
1 (3%) 10 (33%) 12 (40%) 7 (23%) 37%
2 (7%) 16 (53%) 6 (20%) 6 (20%) 60%†
None Slight Moderate Severe Improvement rate *Accumulated
Control group (no. of patients) Initial registration — — 9 (30%) 21 (70%)
2nd week
2nd and 4th weeks*
0 7 (23%) 9 (30%) 14 (47%) 23%
0 10 (33%) 8 (27%) 12 (40%) 33%†
results of second- and fourth-week examination. test, P = .019.
†Cochran-Mantel-Haenszel
Table IV. Changes in TMJ dysfunction: Individual median Treatment group
Maximal mouth opening (mm) Joint pain at rest (VAS) Joint pain on opening and closing (VAS) Joint pain on chewing (VAS) Interference with daily life (VAS)
Control group
Entry
2nd and 4th week
P value
Entry
2nd and 4th week
P value
29 0 51.5 53.5 46.5
37.5 0 28 25.5 22
.000 .711 .001 .001 .001
30 0 51.5 57 30
33.5 0 32 22 28.5
.029 .579 .004 .036 .290
P values calculated with Wilcoxon rank sum test. VAS, Visual analog scale.
Table V. Difference in values between entry and outcome of 4-week study Maximal mouth opening (mm) Joint pain at rest (VAS) Joint pain on opening and closing (VAS) Joint pain on chewing (VAS) Interference with daily life (VAS)
Treatment group
Control group
P value
7 0 –26 –20 –20
1.5 0 –13 –6 –1.5
.005 .823 .297 .162 .040
P values calculated with Mann-Whitney U test. Values shown as median. VAS, Visual analog scale.
month period without treatment. Therefore, the estimated rate of improvement for the control group during the first month would be 10% to 20%. The reported improvement rate for combining NSAIDs and motion exercises was 43.5% after a 3-month treatment.11 Therefore, it was assumed that the improvement rate of the treatment and control groups would be 15% and 50%, respectively, given a dropout rate of 10%. Thus, we estimated that 30 patients would be required per group when a 2-sided test was applied to the data (α = 0.05, β = 0.2). Patients were randomized to 1 of the 2 groups. The stratification was made on the basis of the patient’s age (16 to 30 years or 31 to 70 years), closed-lock period (0 to 30 days or more than 31 days), and classification of TMJ dysfunction (moderate or severe dysfunction) by random permuted blocks within strata.16
Statistical and subgroup analysis The improvement rate was calculated by dividing the number of improved cases over the total number of each group. The Cochran-Mantel-Haenszel test adjusted by age, closed-lock period, and TMJ dysfunc-
tion was used for comparing the improvement rates between the 2 groups. P values less than .05 were considered to indicate statistical significance. Subgroup analysis was performed by using the Wilcoxon rank sum test, the Mann-Whitney U test, or the Fisher exact test. Our data were analyzed by using SAS/STAT, version 6.12 (SAS Institute Inc, Cary, NC, 1997).
RESULTS According to the classification of TMJ dysfunction, there was no statistically significant difference between the 2 groups on the second week of follow-up. However, at the end of the 4-week period of the study, the treatment group improved by 60% compared with 33% in the control group (Table III, P < .019). The number needed to treat for benefit was 3.75, with 95% CI 2.103 to 65.935. When values were compared between the entry and the outcome of the 4-week study, significant improvement was found in maximal mouth opening, pain on opening and closing, and pain on chewing in both groups (Table IV). When the difference in values
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Table VI. Changes in TMJ dysfunction: Stratified initial degree
Table VII. Baseline characteristics and improvement rate
Initial degree of TMJ dysfunction Treatment group Moderate
No. of patients 10
Severe
20
Total
30
Control group Moderate
9
Severe
21
Total
30
2nd and 4th week
Improvement rate
Improved 4 Not improved 6 Improved 14 Not improved 6 Improved 18 Not improved 12
40% 60% 70% 30% 60% 40%
Improved 3 Not improved 6 Improved 7 Not improved 14 Improved 10 Not improved 20
33% 67% 33% 67% 33% 67%
between the entry and the outcome of the 4-week study were compared between treatment and control groups, maximal mouth opening and interference with daily life showed significant improvement in the treatment group (Table V). When analyzed according to the degree of TMJ dysfunction, the patients with severe dysfunction responded better to the treatment than the other patients (Table VI). With respect to age, patients older than 31 years responded better than those younger than 30 years (Table VII). When the results were interpreted according to the period of closed lock, patients with a longer period of closed lock improved more after treatment.
DISCUSSION This study proved that a combination of NSAIDs and physical therapy administered for 4 weeks was effective as a primary treatment for patients with disk displacement without reduction and absence of osseous changes. This treatment significantly reduced pain and interference with daily life and improved maximal mouth opening. In a randomized study, it is important to select patients with TMD on the basis of both clinical and MRI findings. According to our previous study,16 clinical examination alone misdiagnosed 27% of the patients. This is because of the absence of typical clinical manifestations of disk displacement without reduction. On the other hand, MRI alone could not show the degrees of TMJ dysfunction.16 Diagnoses of patients included in the study were verified by clinical and MRI findings. Therefore, patient selection for this study satisfied all the criteria needed. Both age and period of locking were influential
Age <30 y ≥31 y Period of closed lock ≤30 d ≥31 d *Fisher
Improvement rate in treatment group
Improvement rate in control group
P value*
59% 62%
44% 17%
.505 .041
75% 55%
71% 22%
1.0 .033
exact test.
factors of disk displacement without reduction in previous studies. Patients younger than 30 years could usually open their mouth wider than patients older than 30 years.16,17 It was also reported that closed lock within the period of 4 weeks was easily reduced by manipulation,18 and patients with a longer duration of locking were less responsive to conservative treatments.19 Therefore, patients in this study were randomly divided according to age and period of locking. This subgrouping was proved to be correct because our results showed 2 significant differences between the control and the treatment group. On the basis of age, patients older than 31 years responded to the treatment better than those younger than 30 years. On the basis of the period of locking, patients with longer period of closed lock responded better to the treatment. We expected that patients with moderate dysfunction should improve more than those with severe dysfunction in both treatment and control groups. However, the results were contrary to our expectation. A significant improvement was noted in the severe dysfunction treatment group. This indicates that combination of NSAIDs and physical therapy is especially effective on patients with severe TMJ dysfunction. It was difficult to decide on the duration of this randomized study. However, it was decided that a period of 4 weeks would be enough for the following reasons: the result of our previous study showed that the average improvement period by NSAIDs and physical therapy was 44.6 days,11 a prolonged administration of NSAIDs might cause adverse reaction, and it is difficult to recruit and follow-up patients without improvement for more than 4 weeks. The results also showed that combination therapy should be used for more than 2 weeks because no significant difference in the improvement rate between the 2 groups occurred until the fourth week. Being the primary referral center for patients with TMD in our institution, our patient population is
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Yuasa et al 675
comparable with other TMJ/TMD clinics.5 There were enough patients to satisfy the sample size needed. Sixty of the 79 eligible patients (76%) were recruited for the study. This high percentage means that the results of this study are reliable.
ment with flat occlusal splint versus no treatment. Oral Surg Oral Med Oral Pathol 1992;73:655-8. Kirk WS Jr, DK Calabrese. Clinical evaluation of physical therapy in the management of internal derangement of the temporomandibular joint. J Oral Maxillofac Surg 1989;47: 113-9. Bertolami CN, Gay T, Clark GT, Rendell J, Shetty V, Liu C, et al. Use of sodium hyaluronate in treating temporomandibular joint disorders: a randomized, double-blind, placebo-controlled clinical trial. J Oral Maxillofac Surg 1993;51:232-42. Dimitroulis G, Dolwick MF, Martinez A. Temporomandibular joint arthrocentesis and lavage for the treatment of closed lock: a follow-up study. Br J Oral Maxillofac Surg 1995;33:23-7. Nitzan DW, Dolwick MF, Martinez GA. Temporomandibular joint arthrocentesis: a simplified treatment for severe, limited mouth opening. J Oral Maxillofac Surg 1991;49:1163-7. Yuasa H, Kurita K, Ogi N, Maki I, Toyama M, Ito Y, et al. Comparison of primary treatments for TMJ closed lock without osteoarthritis: ITT analysis. J Jpn Soc TMJ 1997;9:343-55. Kurita K, Westesson PL, Yuasa H, Toyama M, Machida J, Ogi N. Natural course of untreated symptomatic temporomandibular joint disc displacement without reduction. J Dent Res 1998;77: 361-5. Ad hoc study group on TMJ meniscus study: 1984 criteria for TMJ meniscus surgery. American Association of Oral and Maxillofacial Surgeons; 1984 November 15-28; Chicago, Ill. Goss AN. Toward an international consensus on temporomandibular joint surgery. Int J Oral Maxillofac Surg 1993; 22:78-81. Kurita K, Westesson PL, Yuasa H, Toyama M, Ogi N, Narita Y, et al. Clinical findings of closed lock (2) natural history over a 6 or 12 month period. J Jpn Soc TMJ 1993;5:415-26. Yuasa H, Kurita K, Narita Y, Ogi N, Jinno Y, Kawai T, et al. Clinical findings of closed lock 1. Untreated unilateral closed lock on initial visit. J Jpn Soc TMJ 1991;3:345-52. Minagi S, Nozaki S, Sato T, Tsura H. A manipulation technique for treatment of anterior disk displacement without reduction. J Prosthet Dent 1991;65:686-91. Farrar WB. Characteristics of the condylar path in internal derangements of the TMJ. J Prosthet Dent 1978;39:319-44. Totsuka Y, Sawada A, Nakamura T. Clinical assessment for treatment of patients with closed-lock of the TMJ. Jpn J Oral Maxillofac Surg 1988;34:1325-37.
CONCLUSION The combination of NSAIDs and physical therapy administered for 4 weeks proved to be an effective primary treatment for disk displacement without reduction and without osseous changes. The results of this study are applicable to any patient group, because the sex ratio was similar to the incidence of TMD as previously reported. We thank Nobuyuki Hamajima, MD, MPH, of the Aichi Cancer Center Research Institute Laboratory of Epidemiology, and Per-Lennart Westesson, MD, DDS, PhD, of the Department of Radiology, University of Rochester School of Medicine and Dentistry, for their assistance.
7.
8.
9. 10. 11. 12.
13. 14.
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Reprint requests: Hidemichi Yuasa, DDS, PhD The Second Department of Oral and Maxillofacial Surgery Aichi-Gakuin University Suemori-Dori, Chikusa-ku Nagoya 464-8651 Japan [email protected]